PRELIMINARY TECHNICAL SUPPORT 

DOCUMENT: 

ENERGY EFFICIENCY PROGRAM FOR 

CONSUMER PRODUCTS AND COMMERCIAL 

AND INDUSTRIAL EQUIPMENT: 

BATTERY CHARGERS AND EXTERNAL POWER SUPPLIES 

September 2010 

U.S. Department of Energy 

Assistant Secretary 

Office of Energy Efficiency and Renewable Energy 

Building Technologies Program 

Appliances and Commercial Equipment Standards 

Washington, DC 20585 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

This Document was prepared for the Department of Energy
 

and by staff members of Navigant Consulting, Inc.,
 

D&R International, Ltd.,
 

and Ernest Orlando Lawrence Berkeley National Laboratory
 

EERE-2008-BT-STD-0005 COMMENT 31
TECHNICAL SUPPORT DOCUMENT: 

BATTERY CHARGERS AND EXTERNAL POWER SUPPLIES 

Table of Contents 

CHAPTERS

Executive Summary 

Chapter 1 Introduction 

Chapter 2 Analytical Framework, Comments from Interested Parties, and 

DOE Responses 

Chapter 3 Market and Technology Assessment 

Chapter 4 Screening Analysis 

Chapter 5 Engineering Analysis 

Chapter 6 Product Price Determination 

Chapter 7 Energy Use Analysis 

Chapter 8 Life-Cycle Cost and Payback Period Analyses 

Chapter 9 Shipments Analysis 

Chapter 10 National Impact Analysis 

Chapter 11 Life-Cycle Cost Subgroup Analysis 

Chapter 12 Preliminary Manufacturer Impact Analysis 

Chapter 13 Utility Impact Analysis 

Chapter 14 Employment Impact Analysis 

REPORTS

Report Environmental Assessment for Battery Chargers and External 

Power Supplies 

Report Regulatory Impact Analysis for Battery Chargers and External 

Power Supplies 

EERE-2008-BT-STD-0005 COMMENT 31
APPENDICES

Appendix 3A Battery Charger and External Power Supply Applications 

Appendix 3B Battery Charger and External Power Supply Efficiency 

Programs 

Appendix 3C Evaluation Methods for Differentiating Wall Adapters with 

Charge Control 

Appendix 5A External Power Supply Test Data 

Appendix 5B Battery Charger Test Data 

Appendix 5C Manufacturer Interview Guide 

Appendix 7A Battery Charger and External Power Supply Usage Profiles, 

Application States, and Loading Points 

Appendix 7B Battery Charger and External Power Supply Application-Level 

Unit Energy Consumption Values 

Appendix 8A User Instructions for LCC and PBP Spreadsheets

Appendix 8B Supplementary LCC and PBP Results 

Appendix 8C End-Use Application Inputs for the LCC 

Appendix 8D Residential Discount Rate Distributions 

Appendix 10A Net Present Value under Alternative Electricity Price Scenarios 

Appendix 12A Preliminary MIA Manufacturer Interview Guide 

Appendix 15A Interagency Report on the Social Cost of Carbon 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

EXECUTIVE SUMMARY
 

TABLE OF CONTENTS
 

ES.1 OVERVIEW OF PRELIMINARY ACTIVITIES.............................................................. 1
 

ES.2 OVERVIEW OF THE PRELIMINARY ANALYSES AND THE PRELIMINARY 

TECHNICAL SUPPORT DOCUMENT............................................................................ 3
 

ES.3 KEY RESULTS OF THE ANALYSIS .............................................................................. 4
 

ES.3.1 Determination of Scope ....................................................................................... 4
 

ES.3.2 Market and Technology Assessment ................................................................... 5
 

ES.3.3 Screening Analysis............................................................................................. 12
 

ES.3.4 Engineering Analysis ......................................................................................... 12
 

ES.3.5 Product Price Determination.............................................................................. 18
 

ES.3.6 Energy Use Analysis.......................................................................................... 21
 

ES.3.7 Life-Cycle Cost and Payback Period Analyses ................................................. 23
 

ES.3.8 Shipments Analysis............................................................................................ 31
 

ES.3.9 National Impact Analysis................................................................................... 31
 

ES.3.9.1 National Energy Savings Analysis......................................................... 33
 

ES.3.9.2 Net Present Value Analysis ................................................................... 36
 

ES.3.10 Preliminary Manufacturer Impact Analysis....................................................... 41
 

ES.3.11 Other Analyses................................................................................................... 41
 

ES.4 ISSUES ON WHICH DOE SEEKS PUBLIC COMMENT............................................. 41
 

ES.4.1 Criteria for Identifying Charge Control in Wall Adapters................................. 42
 

ES.4.2 Design Options for Battery Chargers and External Power Supplies ................. 42
 

ES.4.3 Product Classes for Battery Chargers ................................................................ 42
 

ES.4.4 Dissimilarities Between Low Energy, High Voltage Battery Chargers ............ 42
 

ES.4.5 Scaling Within Battery Charger Product Classes .............................................. 42
 

ES.4.6 Medium Energy, Low Voltage Representative Unit for BCs ............................ 42
 

ES.4.7 EPS Representative Units .................................................................................. 43
 

ES.4.8 EPS Max-Tech Value for 2.5-Watt Representative Unit................................... 43
 

ES.4.9 Efficiency Metrics for Multiple-Voltage EPSs.................................................. 43
 

ES.4.10 Representative Product Classes and Units for MADB EPSs............................. 43
 

ES.4.11 Baseline Candidate Standard Level of Efficiency for Medical and MADB EPSs
 

............................................................................................................................ 44
 

ES.4.12 Scaling for EPS Representative Units and CSLs............................................... 44
 

ES.4.13 Cost Estimates for Product Classes not Fully Analyzed.................................... 45
 

ES.4.14 Market Data ....................................................................................................... 45
 

ES.4.15 Product Lifetimes............................................................................................... 45
 

ES.4.16 Estimated Markups and Incremental Markup Assumptions.............................. 45
 

ES.4.17 Sensitivity Analysis Methodology and Results ................................................. 45
 

ES.4.18 Use in the Commercial Sector ........................................................................... 46
 

ES.4.19 Prospects for Substitution in Response to Standards......................................... 46
 

ES.4.20 Usage Profiles .................................................................................................... 46
 

ES.4.21 Selecting Battery Charger Usage Profiles for Use in Determining Compliance
 

with Standards.................................................................................................... 46
 

ES.4.22 Shipment Trends ................................................................................................ 47
 

ES.4.23 Base Case Efficiency Distributions ................................................................... 47
 

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ES.4.24 Quantifying Non-Consumer Benefits ................................................................ 47
 

ES.4.25 Impact on Manufacturers ................................................................................... 47
 

ES.4.26 Cumulative Regulatory Burdens........................................................................ 47
 

ES.4.27 Valuing Airborne Emission Reductions ............................................................ 47
 

LIST OF TABLES
 

TABLE ES.3.1 EXTERNAL POWER SUPPLY PRODUCT CLASSES ..................................... 5
 

TABLE ES.3.2 BATTERY CHARGER PRODUCT CLASSES................................................... 6
 

TABLE ES.3.3 SUMMARY OF EPS SHIPMENTS ..................................................................... 7
 

TABLE ES.3.4 CLASS A EXTERNAL POWER SUPPLY SHIPMENTS BY PRODUCT 

CLASS AND SEGMENT................................................................................................... 7
 

TABLE ES.3.5 NON-CLASS A EXTERNAL POWER SUPPLY SHIPMENTS BY PRODUCT 

CLASS ................................................................................................................................ 8
 

TABLE ES.3.6 SUMMARY OF BATTERY CHARGER SHIPMENTS ................................... 10
 

TABLE ES.3.7 BATTERY CHARGER SHIPMENTS BY PRODUCT CLASS........................ 10
 

TABLE ES.3.8 COST AND EFFICIENCY RELATIONSHIP FOR 2.5W EPS
 

(MANUFACTURER INTERVIEWS) ............................................................................. 13
 

TABLE ES.3.9 COST AND EFFICIENCY RELATIONSHIP FOR 18W EPS
 

TABLE ES.3.10 COST AND EFFICIENCY RELATIONSHIP FOR 60W EPS
 

TABLE ES.3.11 COST AND EFFICIENCY RELATIONSHIP FOR 120W EPS
 

TABLE ES.3.12 COST AND EFFICIENCY RELATIONSHIP FOR BC PRODUCT CLASS 1: 

TABLE ES.3.13 COST AND EFFICIENCY RELATIONSHIP FOR BC PRODUCT CLASS 2: 

TABLE ES.3.14 COST AND EFFICIENCY RELATIONSHIP FOR BC PRODUCT CLASS 3: 

TABLE ES.3.15 COST AND EFFICIENCY RELATIONSHIP FOR BC PRODUCT CLASS 4: 

TABLE ES.3.16 COST AND EFFICIENCY RELATIONSHIP FOR BC PRODUCT CLASS 5: 

TABLE ES.3.17 COST AND EFFICIENCY RELATIONSHIP FOR BC PRODUCT CLASS 6: 

TABLE ES.3.18 COST AND EFFICIENCY RELATIONSHIP FOR BC PRODUCT CLASS 7: 

TABLE ES.3.19 COST AND EFFICIENCY RELATIONSHIP FOR BC PRODUCT CLASS 8: 

TABLE ES.3.20 COST AND EFFICIENCY RELATIONSHIP FOR BC PRODUCT CLASS 9: 

TABLE ES.3.21 COST AND EFFICIENCY RELATIONSHIP FOR BC PRODUCT CLASS 10: 

(MANUFACTURER INTERVIEWS) ............................................................................. 13
 

(MANUFACTURER INTERVIEWS) ............................................................................. 14
 

(MANUFACTURER INTERVIEWS) ............................................................................. 14
 

LOW ENERGY, INDUCTIVE ........................................................................................ 15
 

LOW ENERGY, LOW VOLTAGE ................................................................................. 15
 

LOW ENERGY, MEDIUM VOLTAGE.......................................................................... 15
 

LOW ENERGY, HIGH VOLTAGE ................................................................................ 16
 

MED. ENERGY, LOW VOLTAGE ................................................................................ 16
 

MED. ENERGY, HIGH VOLTAGE................................................................................ 16
 

HIGH ENERGY ............................................................................................................... 17
 

LOW ENERGY, LOW VOLTAGE DC INPUT.............................................................. 17
 

LOW ENERGY, HIGH VOLTAGE DC INPUT............................................................. 17
 

LOW ENERGY, AC OUTPUT........................................................................................ 18
 

TABLE ES.3.22 EXTERNAL POWER SUPPLY MARKUPS BY PRODUCT CLASS........... 20
 

TABLE ES.3.23 BATTERY CHARGER MARKUPS BY PRODUCT CLASS ........................ 21
 

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TABLE ES.3.24 CLASS A EXTERNAL POWER SUPPLY UNIT ENERGY CONSUMPTION 

(KWH/YR)........................................................................................................................ 21
 

TABLE ES.3.25 BATTERY CHARGER USAGE PROFILES * ................................................. 22
 

TABLE ES.3.26 BATTERY CHARGER UNIT ENERGY CONSUMPTION BASED ON 

MANUFACTURER-SUPPLIED DATA (KWH/YR) ..................................................... 22
 

TABLE ES.3.27 BATTERY CHARGER UNIT ENERGY CONSUMPTION BASED ON TEST
 

TABLE ES.3.28 LCC AND PBP RESULTS FOR 2.5W REGULAR AC/DC EXTERNAL
 

TABLE ES.3.29 LCC AND PBP RESULTS FOR 18W REGULAR AC/DC EXTERNAL
 

TABLE ES.3.30 LCC AND PBP RESULTS FOR 60W REGULAR AC/DC EXTERNAL
 

TABLE ES.3.31 LCC AND PBP RESULTS FOR 120W REGULAR AC/DC EXTERNAL
 

TABLE ES.3.42 EPS WEIGHTED-AVERAGE LCC SAVINGS SENSITIVITY ANALYSIS
 

AND TEARDOWN DATA (KWH/YR).......................................................................... 23
 

POWER SUPPLIES (MANUFACTURER DATA)......................................................... 24
 

POWER SUPPLIES (MANUFACTURER DATA)......................................................... 25
 

POWER SUPPLIES (MANUFACTURER DATA)......................................................... 25
 

POWER SUPPLIES (MANUFACTURER DATA)......................................................... 25
 

TABLE ES.3.32 LCC AND PBP RESULTS FOR PRODUCT CLASS 1: LOW ENERGY, 

INDUCTIVE BATTERY CHARGERS (MANUFACTURER DATA) .......................... 26
 

TABLE ES.3.33 LCC AND PBP RESULTS FOR PRODUCT CLASS 2: LOW ENERGY, LOW
 

VOLTAGE BATTERY CHARGERS (MANUFACTURER DATA)............................. 26
 

TABLE ES.3.34 LCC AND PBP RESULTS FOR PRODUCT CLASS 2: LOW ENERGY, LOW
 

VOLTAGE BATTERY CHARGERS (TEST/TEARDOWN DATA)............................. 26
 

TABLE ES.3.35 LCC AND PBP RESULTS FOR PRODUCT CLASS 4: LOW ENERGY, 

HIGH VOLTAGE BATTERY CHARGERS (MANUFACTURER DATA).................. 26
 

TABLE ES.3.36 LCC AND PBP RESULTS FOR PRODUCT CLASS 4: LOW ENERGY, 

HIGH VOLTAGE BATTERY CHARGERS (TEST/TEARDOWN).............................. 27
 

TABLE ES.3.37 LCC AND PBP RESULTS FOR PRODUCT CLASS 5: MEDIUM ENERGY, 

LOW VOLTAGE BATTERY CHARGERS (MANUFACTURER DATA)................... 27
 

TABLE ES.3.38 LCC AND PBP RESULTS FOR PRODUCT CLASS 5: MEDIUM ENERGY, 

LOW VOLTAGE BATTERY CHARGERS (TEST/TEARDOWN DATA) .................. 27
 

TABLE ES.3.39 LCC AND PBP RESULTS FOR PRODUCT CLASS 7: HIGH ENERGY 

BATTERY CHARGERS (MANUFACTURER DATA)................................................. 27
 

TABLE ES.3.40 LCC AND PBP RESULTS FOR PRODUCT CLASS 10: LOW ENERGY, AC 

OUT BATTERY CHARGERS (MANUFACTURER DATA)........................................ 28
 

TABLE ES.3.41 LCC AND PBP RESULTS FOR PRODUCT CLASS 10: LOW ENERGY, AC 

OUT BATTERY CHARGERS (TEST/TEARDOWN DATA) ....................................... 28
 

SUMMARY...................................................................................................................... 29
 

TABLE ES.3.43 EPS WEIGHTED-AVERAGE LCC SAVINGS BY CSL................................ 29
 

TABLE ES.3.44 BC WEIGHTED-AVERAGE LCC SAVINGS SENSITIVITY ANALYSIS
 

SUMMARY...................................................................................................................... 30
 

TABLE ES.3.45 BC WEIGHTED-AVERAGE LCC SAVINGS BY PRODUCT CLASS ........ 31
 

TABLE ES.3.46 ESTIMATED NATIONAL ANNUAL ENERGY CONSUMPTION OF
 

EXTERNAL POWER SUPPLIES SHIPPED IN 2008.................................................... 32
 

TABLE ES.3.47 ESTIMATED NATIONAL ANNUAL ENERGY CONSUMPTION OF
 

BATTERY CHARGERS SHIPPED IN 2008 .................................................................. 33
 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

TABLE ES.3.48 NATIONAL ENERGY SAVINGS POTENTIAL FROM AMENDED
 

STANDARDS FOR CLASS A EXTERNAL POWER SUPPLIES (TRILLION BTU) . 34
 

TABLE ES.3.49 NATIONAL ENERGY SAVINGS POTENTIAL FROM NEW STANDARDS 

FOR BATTERY CHARGERS (TRILLION BTU), MANUFACTURER DATA........... 35
 

TABLE ES.3.50 NATIONAL ENERGY SAVINGS POTENTIAL FROM NEW STANDARDS 

FOR BATTERY CHARGERS (TRILLION BTU), TEST AND TEARDOWN DATA. 36
 

TABLE ES.3.51 NET PRESENT VALUE OF AMENDED STANDARDS FOR CLASS A 

EXTERNAL POWER SUPPLIES AT A 3 PERCENT DISCOUNT RATE (2009$ 

MILLIONS) ...................................................................................................................... 37
 

TABLE ES.3.52 NET PRESENT VALUE OF AMENDED STANDARDS FOR EXTERNAL
 

POWER SUPPLIES AT A 7 PERCENT DISCOUNT RATE (2009$ MILLIONS) ....... 37
 

TABLE ES.3.53 NET PRESENT VALUE OF NEW STANDARDS FOR BATTERY 

CHARGERS AT A 3 PERCENT DISCOUNT RATE (2009$ MILLIONS), 

MANUFACTURER DATA ............................................................................................. 38
 

TABLE ES.3.54 NET PRESENT VALUE OF NEW STANDARDS FOR BATTERY 

CHARGERS AT A 7 PERCENT DISCOUNT RATE (2009$ MILLIONS), 

MANUFACTURER DATA ............................................................................................. 39
 

TABLE ES.3.55 NET PRESENT VALUE OF NEW STANDARDS FOR BATTERY
 

CHARGERS AT A 3 PERCENT DISCOUNT RATE (2009$ MILLIONS), TEST AND 

TEARDOWN DATA........................................................................................................ 40
 

TABLE ES.3.56 NET PRESENT VALUE OF NEW STANDARDS FOR BATTERY
 

CHARGERS AT A 7 PERCENT DISCOUNT RATE (2009$ MILLIONS), TEST AND 

TEARDOWN DATA........................................................................................................ 40
 

LIST OF FIGURES
 

FIGURE ES.1.1 FLOW DIAGRAM OF ANALYSES FOR THE BATTERY CHARGER AND
 

EXTERNAL POWER SUPPLY RULEMAKING PROCESS .......................................... 2
 

FIGURE ES.3.1 DISTRIBUTION CHANNELS FOR BATTERY CHARGERS AND
 

EXTERNAL POWER SUPPLIES ................................................................................... 19
 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

EXECUTIVE SUMMARY
 

ES.1 OVERVIEW OF PRELIMINARY ACTIVITIES
 

By statute, the U.S. Department of Energy (DOE) must establish energy conservation 

standards that are technologically feasible and economically justified, and would achieve the 

maximum improvement in energy efficiency. 42 U.S.C. § 6295(o)(2)(B). This executive 

summary describes the preliminary activities that DOE conducted in consideration of energy 

conservation standards for battery chargers (BCs) and external power supplies (EPSs) and 

summarizes key results from DOE’s preliminary analyses. Additionally, the executive summary 

identifies specific issues about which DOE seeks comments from interested parties. These issues 

are listed in section 4 of the executive summary, which are highlighted in the public meeting 

presentation, and discussed further in the relevant sections of the preliminary technical support 

document (TSD). 

Figure ES.1.1 presents a summary of the analytical components of the standards-setting 

process and illustrates how key results are generated. The focal point of the figure is the center 

column, labeled “Analyses.” The columns labeled “Key Inputs” and “Key Outputs” show how 

the analyses fit into the process and how they relate to each other. Key inputs are the types of 

data and other information that the analyses require. Some key information is obtained from 

public sources but others may be collected from interested parties or persons having special 

knowledge and expertise. Key outputs are analytical results that feed directly into the standards 

setting process. The issues on which DOE seeks comment from interested parties derive from the 

key results that are generated by the preliminary analyses. Arrows connecting analyses show the 

types of information that feed from one analysis into another. 

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EERE-2008-BT-STD-0005 COMMENT 31
 

Utility Impact

Analysis

Notice of Proposed Rulemaking (NO))

Final Rule

Approaches Key Inputs Analyses Key Outputs

Market and Technology

Assessment

Screening Analysis

Engineering Analysis

Product Price

Determination Life-Cycle Cost and 

Payback Period 

Analyses

National Impact

Analysis

Energy Use

Revise Preliminary

Analyses

Life-Cycle Cost 

Sub-Group Analysis

Manufacturer Impact 

Analysis

Shipments

Analysis

Employment Impact

Analysis

Revise Analyses

• Product Classes

• Technology Options

• Industry Cash Flow

• Sub-Group Cash-Flow

• Direct Employment Impacts

• Competitive Impacts

• Cumulative Regulatory Burden

• Product Designs

• Life-Cycle Costs

• Payback Periods

• National Energy Savings

• Net Present Values

• National Employment Impacts

• Revised Results

• Characterize Industry

• Market Segmentation

• Non-Regulatory Programs

Framework Document

• Efficiency-Level Approach

• Design Option Approach

• Energy Prices

• Installation Costs

• Maintenance & Repair Costs

• Accounting Approach

• Backcast and Forecast

• Market Saturation

• Stakeholder Comments

• Demographics

• Manufacturer Interviews

• GRIM Analysis

• Emission Rates

• National Energy Savings

• Stakeholder Comments

• Identify Firms/Products

• Historical Shipments

•Retail Price Collection and

Analysis

• Manufacturer Prices

• Average Costs

• Manufacturer Financial Data

Design Options

Product Classes

Retail 

Prices

Design Energy/ Use

Advance Notice of Proposed Rulemaking (ANO)

• Efficiency/Performance

• Commercial Products

Candidate

Standard 

Levels

• Analysis of Energy Use 

Data

Environmental

Assessment

Regulatory Impact

Analysis

Technology Options

• Emission Estimates

• Utility Load Factors

• National Energy Savings

• Non-Regulatory

Alternatives

• NEMS-BT

• ImSET

• NEMS-BT

• Design Options

• Energy Price Forecasts

• Site-to-Source Factors

• Energy-Efficiency Levels

Direct Employment 

Impacts

• National Energy Savings

• National Product Costs

• National Operating Costs

• Utility Impacts

• Analysis of Market Data

• Analysis of Product Data

• Life-Cycle Costs

• Payback Periods

• Installation

Costs

• Maint Costs

• Repair Costs

• UEC

• Energy Prices

Annual Energy Use (UEC)

Preliminary 

Manufacturer Impact 

Analysis

• Manufacturer Prices

• Average Costs

• Conversion Capital Expenditures

• Direct Employment Impacts

• National Energy Savings

• Net Present Values

• Trial Standard Levels (TSLs)

TSLs

• Product Prototypes

Energy-Efficiency 

Levels

• Department of Justice Review

Product Designs

Utility Impact

Analysis

Publish Notice of Proposed Rulemaking (NOPR)

Final Rule

Approaches Key Inputs Analyses Key Outputs

Market and Technology

Assessment

Screening Analysis

Engineering Analysis

Product Price

Determination Life-Cycle Cost and 

Payback Period 

Analyses

National Impact

Analysis

Energy Use

Analyses

Life-Cycle Cost 

Sub-Group Analysis

Manufacturer Impact 

Analysis

Shipments

Analysis

Employment Impact

Analysis

Revise Analyses

• Product Classes

• Technology Options

• Industry Cash Flow

• Sub-Group Cash-Flow

• Direct Employment Impacts

• Competitive Impacts

• Cumulative Regulatory Burden

• Product Designs

• Life-Cycle Costs

• Payback Periods

• National Energy Savings

• Net Present Values

• National Employment Impacts

• Revised Results

• Characterize Industry

• Market Segmentation

• Non-Regulatory Programs

Publish Framework Document

• Efficiency-Level Approach

• Design Option Approach

• Energy Prices

• Installation Costs

• Maintenance & Repair Costs

• Accounting Approach

• Backcast and Forecast

• Market Saturation

• Stakeholder Comments

• Demographics

• Manufacturer Interviews

• GRIM Analysis

• Emission Rates

• National Energy Savings

• Stakeholder Comments

• Identify Firms/Products 

• Historical Shipments

•Retail Price Collection and

Analysis

• Manufacturer Prices

• Average Costs

• Manufacturer Financial Data

Design Options

Product Classes

Retail 

Prices

Design Energy/ Use

Publish Preliminary Analyses

• Efficiency/Performance

• Commercial Products

Candidate

Standard 

Levels

• Analysis of Energy Use 

Data

Environmental

Assessment

Regulatory Impact

Analysis

Technology Options

• Emission Estimates

• Utility Load Factors

• National Energy Savings

• Non-Regulatory

Alternatives

• NEMS-BT

• ImSET

• NEMS-BT

• Design Options

• Energy Price Forecasts

• Site-to-Source Factors

• Energy-Efficiency Levels

Direct Employment 

Impacts

• National Energy Savings

• National Product Costs

• National Operating Costs

• Utility Impacts

• Analysis of Market Data

• Analysis of Product Data

• Life-Cycle Costs

• Payback Periods

• Installation

Costs

• Maint Costs

• Repair Costs

• UEC

• Energy Prices

Annual Energy Use (UEC)

Preliminary 

Manufacturer Impact 

Analysis

• Manufacturer Prices

• Average Costs

• Conversion Capital Expenditures

• Direct Employment Impacts

• National Energy Savings

• Net Present Values

• Trial Standard Levels (TSLs)

TSLs

• Product Prototypes

Energy-Efficiency 

Levels

• Department of Justice Review

Product Designs

Figure ES.1.1 Flow Diagram of Analyses for the Battery Charger and External Power 

Supply Rulemaking Process 

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EERE-2008-BT-STD-0005 COMMENT 31
 

ES.2 OVERVIEW OF THE PRELIMINARY ANALYSES AND THE PRELIMINARY 

TECHNICAL SUPPORT DOCUMENT 

For the preliminary stage, DOE publishes a notice of public meeting (NOPM) in the 

Federal Register, which announces the availability of the preliminary technical support 

document, the date and place of the public meeting, and presentation materials interested parties 

may review before the public meeting. In addition, the NOPM summarizes the major analyses 

DOE developed in the preliminary stage of the rulemaking. The preliminary TSD describes each 

preliminary analysis in detail, providing detailed descriptions of inputs, sources, methodologies, 

and results. 

Chapter 2 provides an overview of each preliminary analysis, the comments received on 

the analytical approaches DOE described in the framework document, and DOE’s responses to 

those comments. The following chapters of the preliminary TSD address the analyses performed 

for the preliminary stage of the rulemaking. 

A market and technology assessment characterizes the relevant product markets and 

technology options, including prototype designs (chapter 3). 

A screening analysis reviews each technology option to determine whether it is 

technologically feasible; is practicable to manufacture, install, and service; would adversely 

affect product utility or product availability; or would have adverse impacts on health and safety 

(chapter 4). 

An engineering analysis develops cost-efficiency relationships that show a 

manufacturer’s cost of achieving increased efficiency. DOE uses manufacturer markups to 

convert bill of materials (BOM) cost and manufacturer production cost (MPC) to manufacturer 

selling price (MSP) (chapter 5). 

A markups analysis converts the manufacturer costs derived in the engineering analysis 

to final product prices (chapter 6). 

An energy use analysis determines the annual energy use in the field of the considered 

products (chapter 7). 

Life-cycle cost (LCC) and payback period (PBP) analyses calculate, at the consumer 

level, the discounted savings in operating costs throughout the estimated average life of the 

covered products, compared to any increase in the products’ installed cost likely to result directly 

from the imposition of a given standard. DOE calculated three sets of LCC results to determine 

potential savings based on a “reference case” and to characterize possible variations in a highsavings case and a low-savings case (chapter 8). 

A shipments analysis forecasts product shipments. That forecast is then used to calculate 

the impacts of standards on national energy consumption, the net present value (NPV) of 

consumer costs and savings, and future manufacturer cash flows (chapter 9). 

3 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

A national impact analysis (NIA) assesses the cumulative national energy savings (NES) 

from standards and the NPV of consumer costs and savings associated with standards at different 

efficiency levels (chapter 10). 

A preliminary manufacturer impact analysis (MIA) assesses the potential impacts of 

energy conservation standards on manufacturers, such as effects on expenditures for capital 

conversion, marketing costs, shipments, and research and development costs (chapter 12). 

The remaining chapters of the preliminary TSD address the analyses to be performed at 

the NOPR stage: 

An LCC consumer subgroup analysis evaluates the effects of energy conservation standards 

on various national subgroups of the population (chapter 11). 

A utility impact analysis examines impacts of energy conservation standards on the 

generation capacity of electric utilities (chapter 13). 

An employment impact analysis examines the effects of energy conservation standards on 

national employment (chapter 14). 

An environmental assessment examines the effects of energy conservation standards on 

various airborne emissions (chapter 15). 

A regulatory impact analysis examines the national impacts of non-regulatory alternatives to 

mandatory energy conservation standards (chapter 16). 

ES.3 KEY RESULTS OF THE ANALYSIS 

The following sections describe in detail the key analyses DOE has performed to date. 

ES.3.1 Determination of Scope 

This standards rulemaking concerns all BCs and EPSs, which are defined as follows: 

The term battery charger means a device that charges batteries for consumer 

products, including battery chargers embedded in other consumer products. (42 

U.S.C. 6291(32)) 

The term external power supply means an external power supply circuit that is used 

to convert household electric current into DC current or lower-voltage AC current to 

operate a consumer product. (42 U.S.C. 6291(36)(A)) 

Non-Class A EPSs were not initially within the scope of this standards rulemaking. 

However, DOE recently determined that standards are warranted for these products in a final 

determination published on May 14, 2010. 75 FR 27170. As a result, non-Class A EPSs are 

included in the preliminary market and technology assessment, markup analysis, and shipments 

analysis. The preliminary engineering analysis for non-Class A EPSs includes representative 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

product classes, representative units, and CSLs, but does not include non-Class A EPS costefficiency outputs. Hence, non-Class A EPSs are not included in those analyses that make use of 

engineering outputs, i.e., the LCC and NIA. DOE intends to conduct a comprehensive analysis of 

potential standards for these products in the NOPR stage of the rulemaking. See chapter 2 for 

further discussion of scope. 

ES.3.2 Market and Technology Assessment 

A market and technology assessment characterizes the relevant product markets and 

technology options, including prototype designs. See chapter 3 for details. 

DOE generally divides covered products into product classes by the type of energy used 

or by capacity or other performance-related features that affect efficiency. Different energy 

conservation standards may apply to different product classes. (42 U.S.C. 6295(q)) 

DOE is considering amending standards for Class A EPSs and creating new standards for 

non-Class A EPSs. DOE is considering classifying EPSs by output type, output voltage, output 

power, and (in the case of certain non-Class A EPSs) application, as shown in Table ES.3.1. 

Table ES.3.1 External Power Supply Product Classes 

Product Class ID 

Class A 

DC Output Basic Voltage A1 

Low Voltage A2 

AC Output Basic Voltage A3 

Low Voltage A4 

Non-Class A 

Multiple-Voltage 

100 W X1 

≥100 W X2 

High Power >250 W H1 

For Medical Devices 

DC Output Basic Voltage M1 

Low Voltage M2 

AC Output Basic Voltage M3 

Low Voltage M4 

For Motor-Operated 

BC Applications and 

Detachable Batteries 

(MADB) 

DC Output Basic Voltage B1 

Low Voltage B2 

AC Output Basic Voltage B3 

Low Voltage B4 

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DOE is also considering new standards for BCs. DOE is considering classifying BCs by 

input and output type, battery energy, battery voltage, and input voltage, as shown in Table 

ES.3.2. 

Table ES.3.2 Battery Charger Product Classes 

Input-Output Battery Energy Battery Voltage Product Class 

ID 

Inductive Connection 1 

<100 Wh <4 V 2 

AC-DC 

4–10 V 3 

>10 V 4 

<20 V 5 

100–3000 Wh 

≥20 V 6 

>3000 Wh 7 

DC-DC <9 V Input 8 

≥9 V Input 9 

AC-AC AC Output from Battery 10 

The assessment addresses (1) manufacturer market share and characteristics, (2) existing 

regulatory and non-regulatory initiatives for improving product efficiency, and (3) trends in 

product characteristics and retail markets. This information yielded supporting data and resource 

material on which DOE relied throughout the analysis. 

DOE reviews published literature and interviewed manufacturers to develop an overall 

understanding of the BC and EPS industries. Industry publications, including trade journals, 

literature from manufacturers, government agencies, and trade organizations provided the bulk of 

the information, including: (1) manufacturers and their market shares, (2) shipments by 

application, (3) product characteristics, and (4) industry trends. DOE estimates that just over 300 

million EPSs and just over 400 million BCs shipped in 2008. A summary of EPS shipments is 

presented in Table ES.3.3. A detailed list of shipments by product class for Class A EPSs and 

non-Class A EPSs is displayed in Table ES.3.4 and Table ES.3.5, respectively. A summary of 

BC shipments is presented in Table ES.3.6. A detailed list of shipments by product class for BCs 

is displayed in Table ES.3.7. 

6 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

Table ES.3.3 Summary of EPS Shipments 

EPS Product Class 2008 EPS Shipments 

(thousands) 

Class A1 (DC Output, Basic Voltage) 206,176 

Class A2 (DC Output, Low Voltage) 72,195 

Class A3 (AC Output, Basic Voltage) 7,994 

Class A4 (AC Output, Low Voltage) 2,250 

Non-Class A 12,405 

All EPSs 301,021 

Table ES.3.4 Class A External Power Supply Shipments by Product Class and Segment 

Top Applications by Shipments 

2008 EPS 

Shipments 

(thousands) 

Percent of 

Shipments 

Product Class A1 (DC Output, Basic Voltage): 0-10.25 W 

1 Answering Machines 20,175 26.5% 

2 Cordless Phones 19,151 25.1% 

3 Mobile Phones 13,140 17.2% 

4 Portable Video Game Systems 10,884 14.3% 

5 In-Vehicle GPS 7,660 10.0% 

Other 5,217 6.8% 

Total 76,227 100.0% 

Product Class A1 (DC Output, Basic Voltage): 10.25-39 W 

1 LAN Equipment 27,581 41.3% 

2 VoIP Adapters 8,845 13.3% 

3 Digital Picture Frames 7,472 11.2% 

4 Portable DVD Players 7,140 10.7% 

5 MP3 Speaker Docks 7,012 10.5% 

Other 8,671 13.0% 

Total 66,721 100.0% 

Product Class A1 (DC Output, Basic Voltage): 39-90 W 

1 Notebooks 30,225 57.0% 

2 Video Game Consoles 13,512 25.5% 

3 Ink Jet Imaging Equipment 5,557 10.5% 

4 Netbooks 3,700 7.0% 

Total 56,776 100.0% 

Product Class A1 (DC Output, Basic Voltage): 90-250 W 

1 Notebooks 10,075 98.4% 

2 LED Monitors 160 1.6% 

Total 10,235 100.0% 

7 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

Top Applications by Shipments 

2008 EPS 

Shipments 

(thousands) 

Percent of 

Shipments 

Product Class A2 (DC Output, Low Voltage) 

1 Mobile Phones 52,560 72.8% 

2 In-Vehicle GPS 7,660 10.6% 

3 MP3 Players 4,373 6.1% 

4 Portable Video Game Systems 2,893 4.0% 

5 Personal Digital Assistants 1,582 2.2% 

Other 3,127 4.3% 

Total 72,195 100.0% 

Product Class A3 (AC Output, Basic Voltage) 

1 Home Security Systems 4,219 52.8% 

2 Aquarium Accessories 1,750 21.9% 

3 Water Softeners/Purifiers 1,150 14.4% 

4 Indoor Fountains 500 6.3% 

5 Irrigation Timers 375 4.7% 

Total 7,994 100.0% 

Product Class A4 (AC Output, Low Voltage) 

1 Aquarium Accessories 1,750 77.8% 

2 Indoor Fountains 500 22.2% 

Total 2,250 100.0% 

Table ES.3.5 Non-Class A External Power Supply Shipments by Product Class 

Top Applications by Shipments 

2008 EPS 

Shipments 

(thousands) 

Percent of 

Shipments 

Product Class X1(Multiple-Voltage) 

1 Ink Jet Imaging Equipment 3,782 100.0% 

Total 3,782 100.0% 

Product Class X2 (Multiple Voltage) 

1 Gaming System (multi-voltage EPS) 4,901 100.0% 

Total 4,901 100.0% 

Product Class H1(High Power) 

1 Amateur Radios 3 100.0% 

Total 3 100.0% 

Product Class M1(Medical Devices) 

1 Sleep Apnea Machines 1,000 65.2% 

2 Medical Nebulizers 450 29.3% 

3 Portable O2 Concentrators - Others 50 3.3% 

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Top Applications by Shipments 

2008 EPS 

Shipments 

(thousands) 

Percent of 

Shipments 

4 Blood Pressure Monitors 25 1.6% 

5 Portable O2 Concentrators - Higher Output 9 0.6% 

Total 1,534 

Product Class M2 (Medical Devices) 

1 Blood Pressure Monitors 25 100.0% 

Total 25 100.0% 

Product Class M3 (Medical Devices) 

[no products identified] 

Total 0 

Product Class M4 (Medical Devices) 

[no products identified] 

Total 0 

Product Class B1(MADB) 

1 Toy Ride-On Vehicles 355 18.8% 

2 RC Toys 350 18.6% 

3 DIY Power Tools (External) 281 14.9% 

4 DIY Power Tools (Integral) 234 12.4% 

5 Handheld Vacuums 209 11.1% 

Other 457 24.2% 

Total 1,884 100.0% 

Product Class B2 (MADB) 

1 Shavers 164 59.7% 

2 Beard and Mustache Trimmers 59 21.3% 

3 Hair Clippers 38 13.8% 

4 Can Openers 14 5.2% 

Total 275 100.0% 

Product Class B3 (MADB) 

[no products identified] 

Total 0 

Product Class B4 (MADB) 

[no products identified] 

Total 0 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

Table ES.3.6 Summary of Battery Charger Shipments 

BC Product Class 2008 BC Shipments 

(thousands) 

Class 1 (Low Energy, Inductive) 5,354 

Class 2 (Low Energy, Low Voltage) 206,221 

Class 3 (Low Energy, Medium Voltage) 23,116 

Class 4 (Low Energy, High Voltage) 69,758 

Class 5 (Medium Energy, Low Voltage) 2,333 

Class 6 (Medium Energy, High Voltage) 940 

Class 7 (High Energy) 214 

Class 8 (Low Energy, <9 V Input) 71,825 

Class 9 (Low Energy, ≥9 V Input) 15,519 

Class 10 (Low Energy, AC Output from Battery) 6,900 

Total 402,180 

Table ES.3.7 Battery Charger Shipments by Product Class 

Top Applications by Shipments 

2008 BC 

Shipments 

(thousands) 

Percent of 

Shipments 

Product Class 1 (Low Energy, Inductive) 

1 Rechargeable Toothbrushes 4,868 90.9% 

2 Rechargeable water Jets 487 9.1% 

Total 5,354 100.0% 

Product Class 2 (Low Energy, Low Voltage) 

1 Mobile Phones 105,120 51.0% 

2 Answering Machines 20,175 9.8% 

3 Cordless Phones 19,151 9.3% 

4 Portable Video Game Systems 13,777 6.7% 

5 Digital Cameras 10,879 5.3% 

Other 37,119 18.0% 

Total 206,221 100.0% 

Product Class 3 (Low Energy, Medium Voltage) 

1 Portable DVD Players 7,140 30.9% 

2 Camcorders 4,206 18.2% 

3 Toy Ride-On Vehicles 3,548 15.3% 

4 RC Toys 2,100 9.1% 

5 DIY Power Tools (External) 1,753 7.6% 

Other 4,369 18.9% 

Total 23,116 100.0% 

10 

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Top Applications by Shipments 

2008 BC 

Shipments 

(thousands) 

Percent of 

Shipments 

Product Class 4 (Low Energy, High Voltage) 

1 Notebooks 40,300 57.8% 

2 Professional Power Tools 11,688 16.8% 

3 DIY Power Tools (External) 5,259 7.5% 

4 Netbooks 3,700 5.3% 

5 Handheld Vacuums 2,797 4.0% 

Other 6,014 8.6% 

Total 69,758 100.0% 

Product Class 5 (Medium Energy, Low Voltage) 

1 Toy Ride-On Vehicles 1,774 76.0% 

2 Marine/Automotive/RV Chargers 500 21.4% 

3 Portable O2 concentrator - Others 50 2.1% 

4 Portable O2 concentrator - Higher output 9 0.4% 

Total 2,333 100.0% 

Product Class 6 (Medium Energy, High Voltage) 

1 Electric Scooters 250 26.6% 

2 Mobility Scooters 192 20.4% 

3 Lawn Mowers 182 19.4% 

4 Wheelchairs 166 17.7% 

5 Motorized Bicycles 150 15.9% 

Total 940 100.0% 

Product Class 7 (High Energy) 

1 Golf Carts 214 100.0% 

Total 214 100.0% 

Product Class 8 (Low Energy, <9 V Input) 

1 MP3 Players 39,358 54.8% 

2 Mobile Phones 26,280 36.6% 

3 Digital Cameras 2,720 3.8% 

4 Personal Digital Assistants 1,779 2.5% 

5 Camcorders 1,402 2.0% 

Other 286 0.4% 

Total 71,825 100.0% 

Product Class 9 (Low Energy, ≥9 V Input) 

1 In-Vehicle GPS 15,320 98.7% 

2 Medical Nebulizer 90 0.6% 

3 Portable O2 concentrator – Others 50 0.3% 

4 Flashlights/Lanterns 50 0.3% 

11 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

Top Applications by Shipments 

2008 BC 

Shipments 

(thousands) 

Percent of 

Shipments 

5 Portable O2 concentrator - Higher 

output 9 0.1% 

Total 15,519 100.0% 

Product Class 10 (Low Energy, AC Output from Battery) 

1 Uninterruptible Power Supplies 6,900 100.0% 

Total 6,900 100.0% 

DOE typically uses information about existing and past technology options and prototype 

designs to determine which technologies and combinations of technologies manufacturers use to 

attain higher performance levels. In consultation with interested parties, DOE develops a list of 

technologies to be considered. The identified technologies initially include all those DOE 

believes are technologically feasible. 

ES.3.3 Screening Analysis 

DOE also develops an initial list of options for enhancing efficiency from the 

technologies that the technology assessment identified as feasible. In consultation with interested 

parties, DOE reviews the list to assess whether the technologies are practicable to manufacture, 

install, and service; would adversely affect product utility or availability; or would have adverse 

impacts on health and safety. In the subsequent engineering analysis, DOE further examines the 

technology options that it did not remove from consideration in the screening analysis. See 

chapter 4 of the preliminary TSD for details. 

ES.3.4 Engineering Analysis 

The engineering analysis develops cost-efficiency relationships that show a 

manufacturer’s cost of achieving increased efficiency. DOE uses manufacturer markups to 

convert manufacturer production cost (MPC) to manufacturer selling price (MSP) (chapter 5). 

DOE structured its engineering analysis around two methodologies: (1) test and teardown 

method, which involves testing products for efficiency and determining cost from a detailed bill 

of materials derived from tear-downs and (2) the efficiency-level approach, whereby 

manufacturers provide and explain their costs of achieving increases in energy efficiency at 

discrete levels of efficiency. 

For the Class A external power supplies engineering analysis, DOE analyzed the four 

representative units in product class A1. For each representative unit, DOE chose a baseline level 

(CSL 0), and identified four more efficient replacements: ENERGY STAR 2.0, intermediate, 

best-in-market, and max-tech (CSL 1, CSL 2, CSL 3, CSL 4). For each CSL, DOE calculated the 

manufacturer selling price, measured the average active-mode efficiency and the no-load power, 

and used the values to generate cost-efficiency curves for each representative unit. DOE only 

calculated CSL 4 values from the manufacturer interview method and not the test and teardown 

method, as a max-tech unit is inherently not commercially available. 

12 

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DOE developed two sets of cost-efficiency curves for EPSs: one based on manufacturer data and 

another based on test and teardown data. In summary, for each representative unit, the 

manufacturer data for cost versus efficiency and cost versus no-load power data showed a trend 

of increasing MSPs with higher CSLs, meaning that it costs more to manufacture more efficient 

EPSs. On the other hand, the test and teardown curves’ cost-efficiency relationship was 

inconclusive. In many cases for the test and teardown data, the CSL 3 best-in-market unit was 

the cheapest, and the CSL 0 unit was the most expensive. For all four test and teardown curves, 

representative units’ cost decreased from CSL 1 to CSL 3. 

DOE believes that the results from the test and teardown method are inconclusive 

because they do not show a clear relationship. One reason for this may be that DOE did not 

sufficiently control for all factors affecting cost and efficiency, as explained further in chapter 5. 

Therefore, DOE chose to use only the manufacturer data in its UEC, LCC, and NIA analysis for 

Class A EPSs. For the three representative units’ test and teardown curves where CSL 3 is the 

least expensive, the LCC savings are inherently positive at CSL 3. Table ES.3.8, Table ES.3.9, 

Table ES.3.10, and Table ES.3.11 present the efficiency, no-load power, and MSP difference 

identified for each CSL in the engineering analysis for manufacturer data. The tables present 

both manufacturer data and CSL data in parentheses. All manufacturer data points qualify for the 

CSLs by either meeting or exceeding the CSL efficiency requirements. The MSP difference is 

the incremental price of the EPS above the baseline model. 

Table ES.3.8 Cost and Efficiency Relationship for 2.5W EPS (Manufacturer Interviews) 

CSL 0 CSL 1 CSL 2 CSL 3 CSL 4 

Mfr Data Efficiency [%]: 58.3% 67.9% 71.0% 73.5% 74.0% 

Mfr Data No Load Power [W]: 0.500 0.300 0.130 0.100 0.053 

CSL Description: EISA E. STAR 2.0 Intermediate Best in Market Max Tech 

CSL Eff. [%], (58.3%) (67.9%) (70.9%) (73.2%) (73.9%) 

No-Load Power [W] (0.500) (0.300) (0.200) (0.100) (0.062) 

MSP Difference[$]: $0.00 $0.04 $0.23 $0.31 $0.42 

Table ES.3.9 Cost and Efficiency Relationship for 18W EPS (Manufacturer Interviews) 

CSL 0 CSL 1 CSL 2 CSL 3 CSL 4 

Mfr Data Efficiency [%]: 76.0% 80.3% 83.0% 85.4% 87.5% 

Mfr Data No Load Power [W]: 0.500 0.300 0.200 0.100 0.062 

CSL Description: EISA E. STAR 2.0 Intermediate Best in Market Max Tech 

CSL Eff. [%], (76.0%) (80.3%) (83.0%) (85.0%) (87.3%) 

No-Load Power [W] (0.500) (0.300) (0.200) (0.100) (0.062) 

MSP Difference[$]: $0.00 $0.32 $0.42 $0.79 $1.23 

13 

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Table ES.3.10 Cost and Efficiency Relationship for 60W EPS (Manufacturer Interviews) 

CSL 0 CSL 1 CSL 2 CSL 3 CSL 4 

Mfr Data Efficiency [%]: 85.0% 87.0% 87.0% 88.0% 91.0% 

Mfr Data No Load Power [W]: 0.500 0.500 0.200 0.073 0.073 

CSL Description: EISA E. STAR 2.0 Intermediate Best in Market Max Tech 

CSL Eff. [%], (85.0%) (87.0%) (87.0%) (88.0%) (91.0%) 

No-Load Power [W] (0.500) (0.500) (0.230) (0.210) (0.165) 

MSP Difference[$]: $0.00 $0.24 $0.71 $1.58 $2.90 

Table ES.3.11 Cost and Efficiency Relationship for 120W EPS (Manufacturer Interviews) 

CSL 0 CSL 1 CSL 2 CSL 3 CSL 4 

Mfr Data Efficiency [%]: 85.0% 87.0% 88.0% 88.4% 91.7% 

Mfr Data No Load Power [W]: 0.500 0.500 0.230 0.210 0.165 

CSL Description: EISA E. STAR 2.0 Intermediate Best in Market Max Tech 

CSL Eff. [%], (85.0%) (87.0%) (87.0%) (88.0%) (91.0%) 

No-Load Power [W] (0.500) (0.500) (0.230) (0.210) (0.165) 

MSP Difference[$]: $0.00 $0.66 $1.23 $1.41 $5.03 

For the battery charger engineering analysis, DOE analyzed 10 product classes that cover 

the entire range of consumer BCs available in the market. For each product class, DOE chose 

baseline battery chargers (CSL 0) representative of the least efficient in the market and identified 

more efficient replacements: improved, best-in-market, and max-tech (CSL 1, CSL 2, CSL 3). 

For each CSL, DOE calculated the manufacturer selling price and shipment-weighted average 

annual energy consumption, and used the values to generate cost-efficiency curves. DOE only 

calculated CSL 3 values from the manufacturer interview method and not the test and teardown 

method, as a max-tech unit is inherently not commercially available. 

DOE collected data for 6 of the 10 BC product classes. For the four product classes for 

which DOE did not collect data directly, DOE developed a scaling method to estimate MSP and 

energy consumption values from the results for the other product classes. See chapter 5 of the 

preliminary TSD for details. 

DOE developed cost-efficiency curves for BCs based on test and teardown data as well as 

manufacturer data. For each representative product class, DOE used either test and teardown 

data, manufacturer data, or both to characterize the cost-efficiency relationship for the 

representative unit. Table ES.3.12, Table ES.3.13, Table ES.3.14, Table ES.3.15, Table ES.3.16, 

Table ES.3.17, Table ES.3.18, Table ES.3.19, Table ES.3.20, and Table ES.3.21 present the 

energy consumption and MSP identified for each CSL in the engineering analysis. 

14 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

Table ES.3.12 Cost and Efficiency Relationship for BC Product Class 1: Low Energy, 

Inductive 

MSP from MSP from 

UEC Interviews Teardowns 

CSL kWh/yr 2009$ 2009$ 

0 10.0 $2.05 -

1 7.0 $2.22 -

2 3.5 $2.45 -

3 1.5 $2.60 -

Table ES.3.13 Cost and Efficiency Relationship for BC Product Class 2: Low Energy, Low 

Voltage 

MSP from MSP from 

UEC Interviews Teardowns 

CSL kWh/yr 2009$ 2009$ 

0 10.0 $0.62 -

1 6.0 $1.09 $0.62 

2 1.2 $11.71 $2.62 

3 - - -

Table ES.3.14 Cost and Efficiency Relationship for BC Product Class 3: Low Energy, 

Medium Voltage 

MSP from MSP from 

UEC Interviews Teardowns 

CSL kWh/yr 2009$ 2009$ 

0 10.0 $3.16 -

1 5.4 $4.96 -

2 1.0 $12.99 -

3 - - -

15 

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Table ES.3.15 Cost and Efficiency Relationship for BC Product Class 4: Low Energy, High 

Voltage 

MSP from MSP from 

UEC Interviews Teardowns 

CSL kWh/yr 2009$ 2009$ 

0 39.4 $3.79 $3.79 

1 10.5 $9.52 $6.76 

2 6.1 $12.68 $7.44 

3 - - -

Table ES.3.16 Cost and Efficiency Relationship for BC Product Class 5: Med. Energy, Low 

Voltage 

MSP from MSP from 

UEC Interviews Teardowns 

CSL kWh/yr 2009$ 2009$ 

0 202.7 $18.48 $18.48 

1 159.6 $27.46 $21.71 

2 100.0 $64.14 -

3 75.0 $127.00 -

Table ES.3.17 Cost and Efficiency Relationship for BC Product Class 6: Med. Energy, 

High Voltage 

MSP from MSP from 

UEC Interviews Teardowns 

CSL kWh/yr 2009$ 2009$ 

0 69.3 $18.48 -

1 41.9 $35.87 -

2 25.0 $76.83 -

3 18.0 $139.95 -

16 

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Table ES.3.18 Cost and Efficiency Relationship for BC Product Class 7: High Energy 

MSP from MSP from 

UEC Interviews Teardowns 

CSL kWh/yr 2009$ 2009$ 

0 290.0 $79.01 -

1 250.0 $94.94 -

2 200.0 $127.05 -

3 150.0 $192.32 -

Table ES.3.19 Cost and Efficiency Relationship for BC Product Class 8: Low Energy, Low 

Voltage DC Input 

MSP from MSP from 

UEC Interviews Teardowns 

CSL kWh/yr 2009$ 2009$ 

0 1.5 $0.62 -

1 0.9 $1.42 -

2 0.8 $2.17 -

3 - - -

Table ES.3.20 Cost and Efficiency Relationship for BC Product Class 9: Low Energy, High 

Voltage DC Input 

MSP from MSP from 

UEC Interviews Teardowns 

CSL kWh/yr 2009$ 2009$ 

0 1.3 $0.62 -

1 0.8 $1.11 -

2 0.5 $2.76 -

3 - - -

17 

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Table ES.3.21 Cost and Efficiency Relationship for BC Product Class 10: Low Energy, AC 

Output 

MSP from MSP from 

UEC Interviews Teardowns 

CSL kWh/yr 2009$ 2009$ 

0 19.6 $2.76 $2.76 

1 6.4 $3.93 $2.11 

2 4.0 $4.25 -

3 1.5 $4.64 -

ES.3.5 Product Price Determination 

The product price determination, documented in chapter 6, develops markups at the enduse product manufacturer (referred to as the OEM) and retail stages of the distribution chain to 

convert the estimates of the BC/EPS manufacturer selling prices (derived in the engineering 

analysis) to consumer prices. In developing markups, DOE determined the distribution channels 

for BCs and EPSs and the markup associated with each party in the distribution channel. 

Figure ES.3.1 displays the distribution channels for BCs and EPSs. The gray arrows show the 

most common path to market. 

18 

EERE-2008-BT-STD-0005 COMMENT 31
Figure ES.3.1 Distribution Channels for Battery Chargers and External Power Supplies 

Because the majority of these products pass through an OEM, where they are integrated 

into or packaged with an end-use consumer product, and are later sold through retailers, DOE 

assumes that the markups applied at these stages set the final product price. Composite baseline 

and incremental markups for each EPS and BC product class are shown in Table ES.3.22 and 

Table ES.3.23, respectively. To obtain the final product price, the MSP is multiplied by the 

appropriate composite markups and sales tax rate. DOE used a national average sales tax rate of 

7.23 percent in its analysis. 

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Table ES.3.22 External Power Supply Markups by Product Class 

Output Class ID 

Composite 

Baseline 

Markup 

Composite 

Incremental 

Markup 

Class A 

AC-DC Basic Voltage 

A1: 0-10.25 W 2.16 1.40 

A1: 10.25-39 W 2.00 1.31 

A1: 39-90 W 2.00 1.34 

A1: 120-250 W 1.89 1.31 

Low Voltage A2 2.19 1.47 

AC-AC Basic Voltage A3 2.07 1.31 

Low Voltage A4 2.17 1.33 

Non-Class A 

Multiple-Voltage 

100 W X1 1.99 1.31 

≥100 W X2 2.27 1.45 

High Power >250 W H1 1.69 1.16 

For Medical 

Devices 

AC-DC Basic Voltage M1 2.53 1.48 

Low Voltage M2 2.53 1.48 

AC-AC Basic Voltage M3 * – – 

Low Voltage M4 * – – 

For MotorOperated BC 

Applications 

and Detachable 

Batteries 

(MADB) 

AC-DC Basic Voltage B1 2.16 1.35 

Low Voltage B2 2.01 1.23 

AC-AC 

Basic Voltage B3 * – – 

Low Voltage B4 * – – 

* DOE did not identify products in product classes M3, M4, B3, and B4. 

20 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

Table ES.3.23 Battery Charger Markups by Product Class 

InputOutput Battery 

Energy Voltage Class ID 

Composite 

Baseline 

Markup 

Composite 

Incremental 

Markup 

AC-DC 

<100 Wh 

Inductive Connection 1 2.00 1.23 

<4 V 2 2.13 1.40 

4–10 V 3 2.17 1.33 

>10 V 4 1.98 1.32 

100–3000 Wh 

<20 V 5 2.32 1.37 

≥20 V 6 2.28 1.36 

>3000 Wh 7 2.31 1.37 

DC-DC <9 V Input 8 2.12 1.38 

≥9 V Input 9 2.60 1.69 

AC-AC AC Output from Battery 10 2.01 1.35 

ES.3.6 Energy Use Analysis 

The energy use analysis assesses the potential energy use of higher efficiency products 

and provides the basis for estimating the energy savings used in the LCC and subsequent 

analyses. The DOE BC and EPS test procedures provide standardized results for each mode of 

operation and can serve as the basis for comparing the performance of different appliances under 

the same conditions. However, the way a given BC or EPS is used is also an important 

determinant of its overall energy consumption. 

To determine the variation in field energy use by products that would meet possible 

energy efficiency standards, DOE assigned usage profiles to each BC and EPS application. DOE 

derived these application-specific usage profiles based on comments by interested parties, 

publications, and its own estimates. 

To estimate EPS energy use DOE multiplied annual usage in each application state and 

operating mode (in hours per year) by the power estimates (in watts). These power estimates are 

a function of EPS efficiency and loading. Table ES.3.24 shows DOE’s estimates of the annual 

unit energy consumption of each representative unit at each CSL. 

Table ES.3.24 Class A External Power Supply Unit Energy Consumption (kWh/yr) 

Representative 

Unit CSL 0 CSL 1 CSL 2 CSL 3 CSL 4 

2.5 W 3.6 2.5 1.9 1.7 1.6 

18 W 15.5 11.8 9.7 7.9 6.6 

60 W 11.7 10.3 8.7 7.3 5.4 

120 W 19.4 16.8 14.2 13.6 9.4 

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To determine BC energy usage in the field, DOE multiplied annual usage in each 

operating mode (in hours per day or charges per day) by the power estimates (in watts) or energy 

per charge (in watt hours) from the engineering analysis. The usage profiles DOE developed for 

each product class are shown in Table ES.3.25. 

Table ES.3.25 Battery Charger Usage Profiles 

Product 

Class ID 

Active + 

Maintenance 

No Battery 

(Standby) Unplugged Off Charges 

Hours per Day No. per Day 

1 23.9 0.1 0 0 0.26 

2 9.7 5.0 9.4 0 0.56 

3 5.6 0.2 18.1 0.1 0.22 

4 19.8 0.3 6.9 0.1 0.88 

5 7.7 0.5 15.8 0 0.55 

6 15.4 8.6 0 0 0.46 

7 7.7 8.1 8.1 0 0.36 

8 6.5 7.5 10.1 0 0.43 

9 1.1 0.1 22.8 0 0.15 

10 24.0 0 0 0 0 

Note: Usage times may not sum to 24 hours due to rounding. 

DOE estimated the annual unit energy consumption of BCs in each product class at each 

CSL. Results are displayed in Table ES.3.26 and Table ES.3.27. These values are used in the 

NIA and are the shipment-weighted averages of the application-specific UEC values used in the 

LCC analysis. Chapter 7 provides more details on the methods, data, and assumptions employed 

in the energy use analysis. 

Table ES.3.26 Battery Charger Unit Energy Consumption Based on ManufacturerSupplied Data (kWh/yr) 

Class ID CSL 0 CSL 1 CSL 2 CSL 3 

1 10.0 7.0 3.5 1.5 

2 10.0 6.0 1.2 -

3 10.0 5.4 1.0 -

4 39.4 10.5 6.1 -

5 202.3 158.4 100.0 75.0 

6 69.3 41.9 25.0 18.0 

7 290.0 250.0 200.0 150.0 

8 1.5 0.9 0.6 -

9 1.3 0.8 0.5 -

10 19.6 6.4 4.0 1.5 

22 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

Table ES.3.27 Battery Charger Unit Energy Consumption based on Test and Teardown 

Data (kWh/yr) 

Class ID CSL 0 CSL 1 CSL 2 CSL 3 

1 - - - -

2 - 7.4 1.2 -

3 - - - -

4 39.4 10.5 6.1 -

5 232.7 179.3 - -

6 - - - -

7 - - - -

8 - - - -

9 - - - -

10 19.6 6.4 - -

ES.3.7 Life-Cycle Cost and Payback Period Analyses 

The LCC and PBP analysis is used to determine the economic impact of potential 

standards on end users. The effects of standards on individual end users include changes in 

operating expenses (usually lower) and changes in total installed cost (usually higher). 

DOE analyzed the net effect of these changes for BCs and EPSs, first by calculating the 

changes in end users’ LCCs likely to result from various candidate standard levels compared to a 

base case (no new standards). The LCC calculation considers total installed cost (which includes 

manufacturer selling price, sales taxes, and distribution chain markups), operating expenses 

(energy expenses), product lifetime, and discount rate. Because DOE found no evidence that 

installation, repair, or maintenance costs apply to BCs or EPSs, it excluded those costs from its 

analysis. DOE performed the LCC analysis from the perspective of users of BCs and EPSs. 

The PBP is the amount of time it takes the customer to recover the assumed additional 

installed cost of more efficient products through energy cost savings. Payback analysis is a 

common technique used to evaluate investment decisions. This calculation is known as a simple 

payback period because it does not account for changes in operating expense over time or the 

time value of money. 

The inputs to the PBP calculation are the total installed cost of the product to the end user 

for each efficiency level and the first year’s operating expenditures for each efficiency level. The 

PBP calculation uses the same inputs as the LCC analysis, except that energy price trends and 

discount rates are not needed. The calculation uses energy prices only for the year of the 

compliance date, in this case 2013. 

To accurately estimate the share of consumers that would be affected by a standard at a 

particular efficiency level, DOE’s LCC analysis considered the projected distribution of product 

efficiencies that consumers purchase under the base case (i.e., the case without new energy 

efficiency standards). DOE refers to this distribution of product efficiencies as a base-case 

efficiency distribution. DOE developed base-case efficiency distributions for each of the 

23 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

representative product classes as projected for the year that new standards are assumed to 

become effective (2013). Using the projected distribution of product efficiencies for each 

representative unit, DOE determined the impact of each standard level by sampling consumers 

assigned to each efficiency level in the base case. If a consumer was assigned a product 

efficiency that was greater than or equal to the efficiency of the standard level under 

consideration, the LCC calculation would show that the consumer was not impacted by that 

standard level. 

Table ES.3.28 through Table ES.3.41 show the results of the LCC and PBP analyses for 

the representative units and representative product classes at each considered energy efficiency 

level. Table ES.3.28, Table ES.3.29, Table ES.3.30, and Table ES.3.31 present the EPS results. 

Table ES.3.32, Table ES.3.33, Table ES.3.34, Table ES.3.35, Table ES.3.36, Table 

ES.3.37, Table ES.3.38, Table ES.3.39, Table ES.3.40, and Table ES.3.41 present the BC results. 

Consumers are said to have “no impact” if the base case forecast product assigned to them has a 

greater efficiency than the level indicated by a standard. In the case of the PBP, a very small 

change in operating cost can result in a few extremely large payback periods, which will skew 

the mean payback. In these cases, the median is a better indicator of payback period because it is 

the value at the center of the distribution of results, which is unaffected by results that would be 

considered outliers. 

Figures presented in Chapter 8 show the range of LCC savings and PBPs for all of the 

efficiency levels considered for each representative unit. Chapter 8 provides more details on the 

methods, data, and assumptions used for the LCC and PBP analyses. 

Table ES.3.28 LCC and PBP Results for 2.5W Regular AC/DC External Power Supplies 

(Manufacturer Data) 

CSL Eff.* 

% 

No 

Load 

Power 

W 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Price† 

2009$ 

Avg. 

Operating 

Cost 

2009$ 

Avg. 

LCC† 

2009$ 

Wtd. 

Avg. 

Savings 

2009$ 

Consumers with 

Median 

yrs. 

Mean 

yrs. 

Net 

Cost 

% 

No 

Impact 

% 

Net 

Benefit 

% 

0 58.3 0.500 0.00 1.73 1.73 - - - - - -

1 67.9 0.300 0.06 1.12 1.19 0.19 3.1 66.0 30.9 0.4 1.3 

2 71.0 0.130 0.35 0.90 1.24 0.14 40.5 15.3 44.2 3.6 12.7 

3 73.5 0.100 0.47 0.78 1.25 0.13 44.2 3.2 52.6 3.7 12.7 

4 74.0 0.053 0.63 0.74 1.36 0.02 64.3 0.0 35.7 4.8 17.2 

* “Eff.” stands for “efficiency level.” 

† Based on an incremental MSP over the baseline. 

24 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

Table ES.3.29 LCC and PBP Results for 18W Regular AC/DC External Power Supplies 

(Manufacturer Data) 

CSL Eff.* 

% 

No 

Load 

Power 

W 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Price† 

2009$ 

Avg. 

Operating 

Cost 

2009$ 

Avg. 

LCC† 

2009$ 

Wtd. 

Avg. 

Savings 

2009$ 

Consumers with 

Median 

yrs. 

Mean 

yrs. 

Net 

Cost 

% 

No 

Impact 

% 

Net 

Benefit 

% 

0 76.0 0.500 0.00 6.54 6.54 - - - - - -

1 80.3 0.300 0.44 4.99 5.43 0.33 6.2 65.9 27.9 1.1 4.9 

2 83.0 0.200 0.59 4.11 4.70 0.96 11.5 15.3 73.2 0.8 2.8 

3 85.4 0.100 1.11 3.35 4.45 1.20 18.2 3.3 78.5 1.5 5.5 

4 87.5 0.062 1.73 2.79 4.52 1.13 33.5 0.0 66.5 2.1 8.0 

* “Eff.” stands for “efficiency level.” 

† Based on an incremental MSP over the baseline. 

Table ES.3.30 LCC and PBP Results for 60W Regular AC/DC External Power Supplies 

(Manufacturer Data) 

CSL Eff.* 

% 

No 

Load 

Power 

W 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Price† 

2009$ 

Avg. 

Operating 

Cost 

2009$ 

Avg. 

LCC† 

2009$ 

Wtd. 

Avg. 

Savings 

2009$ 

Consumers with 

Median 

yrs. 

Mean 

yrs. 

Net 

Cost 

% 

No 

Impact 

% 

Net 

Benefit 

% 

0 85.0 0.500 0.00 4.63 4.63 - - - - - -

1 87.0 0.500 0.34 4.08 4.43 0.07 4.8 66.0 29.2 2.4 2.4 

2 87.0 0.200 1.02 3.43 4.46 0.05 50.0 15.3 34.7 3.6 3.6 

3 88.0 0.073 2.28 2.90 5.18 -0.65 88.5 3.3 8.2 5.8 6.0 

4 91.0 0.073 4.18 2.13 6.31 -1.78 96.7 0.0 3.3 7.2 7.2 

* “Eff.” stands for “efficiency level.” 

† Based on an incremental MSP over the baseline. 

Table ES.3.31 LCC and PBP Results for 120W Regular AC/DC External Power Supplies 

(Manufacturer Data) 

CSL Eff.* 

% 

No 

Load 

Power 

W 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Price† 

2009$ 

Avg. 

Operating 

Cost 

2009$ 

Avg. 

LCC† 

2009$ 

Wtd. 

Avg. 

Savings 

2009$ 

Consumers with 

Median 

yrs. 

Mean 

yrs. 

Net 

Cost 

% 

No 

Impact 

% 

Net 

Benefit 

% 

0 85.0 0.500 0.00 6.48 6.48 - - - - - -

1 87.0 0.500 0.92 5.62 6.54 -0.02 24.7 66.1 9.2 3.6 3.4 

2 88.0 0.230 1.72 4.73 6.45 0.05 44.7 15.2 40.1 3.0 2.9 

3 88.4 0.210 1.97 4.53 6.50 0.01 63.1 3.2 33.7 3.3 3.2 

4 91.7 0.165 7.05 3.15 10.20 -3.69 99.8 0.0 0.2 7.6 7.8 

* “Eff.” stands for “efficiency level.” 

† Based on an incremental MSP over the baseline. 

25 

EERE-2008-BT-STD-0005 COMMENT 31
Table ES.3.32 LCC and PBP Results for Product Class 1: Low Energy, Inductive Battery 

Chargers (Manufacturer Data) 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Avg. 

Operating Avg. 

Wtd. 

Avg. 

Consumers with 

Net No Net 

CSL UEC Price Cost LCC Savings Cost Impact Benefit Median Mean 

kWh 2009$ 2009$ 2009$ 2009$ % % % yrs. yrs. 

0 10.0 4.39 4.81 9.20 - - - - - -

1 7.0 4.61 3.37 7.97 0.93 0.0 24.9 75.1 0.7 0.7 

2 3.5 4.91 1.68 6.59 2.14 0.0 12.4 87.6 0.8 0.8 

3 1.5 5.12 0.72 5.84 2.90 0.0 0.0 100.0 0.9 0.8 

Table ES.3.33 LCC and PBP Results for Product Class 2: Low Energy, Low Voltage 

Battery Chargers (Manufacturer Data) 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Avg. 

Operating Avg. 

Wtd. 

Avg. 

Consumers with 

Net No Net 

CSL UEC Price Cost LCC Savings Cost Impact Benefit Median Mean 

kWh 2009$ 2009$ 2009$ 2009$ % % % yrs. yrs. 

0 10.0 1.42 3.30 4.72 - - - - - -

1 6.0 2.13 2.08 4.20 0.20 6.6 60.8 32.6 1.5 2.2 

2 1.2 18.09 0.46 18.54 -13.74 97.2 2.8 0.0 25.4 38.9 

Table ES.3.34 LCC and PBP Results for Product Class 2: Low Energy, Low Voltage 

Battery Chargers (Test/Teardown Data) 

CSL UEC 

kWh 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Price 

2009$ 

Avg. 

Operating 

Cost 

2009$ 

Avg. 

LCC 

2009$ 

Wtd. 

Avg. 

Savings 

2009$ 

Consumers with 

Median 

yrs. 

Mean 

yrs. 

Net 

Cost 

% 

No 

Impact 

% 

Net 

Benefit 

% 

0 10.0 N/A N/A N/A N/A N/A N/A N/A N/A N/A 

1 6.0 1.42 2.48 3.90 - - - - - -

2 1.2 4.43 0.38 4.82 -0.90 73.7 2.8 23.5 4.7 6.7 

Table ES.3.35 LCC and PBP Results for Product Class 4: Low Energy, High Voltage 

Battery Chargers (Manufacturer Data) 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Avg. 

Operating Avg. 

Wtd. 

Avg. 

Consumers with 

Net No Net 

CSL UEC Price Cost LCC Savings Cost Impact Benefit Median Mean 

kWh 2009$ 2009$ 2009$ 2009$ % % % yrs. yrs. 

0 39.4 8.04 16.65 24.69 - - - - - -

1 10.5 16.13 4.31 20.44 0.97 9.0 81.3 9.7 3.4 3.1 

2 6.1 20.60 2.48 23.08 -0.65 53.8 38.3 7.9 9.3 9.1 

26 

EERE-2008-BT-STD-0005 COMMENT 31
Table ES.3.36 LCC and PBP Results for Product Class 4: Low Energy, High Voltage 

Battery Chargers (Test/Teardown) 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Avg. 

Operating Avg. 

Wtd. 

Avg. 

Consumers with 

Net No Net 

CSL UEC Price Cost LCC Savings Cost Impact Benefit Median Mean 

kWh 2009$ 2009$ 2009$ 2009$ % % % yrs. yrs. 

0 39.4 8.04 15.38 23.42 - - - - - -

1 10.5 12.23 4.14 16.38 1.33 0.4 81.5 18.1 1.3 1.6 

2 6.1 13.20 2.52 15.72 1.74 11.1 38.2 50.7 1.5 2.5 

Table ES.3.37 LCC and PBP Results for Product Class 5: Medium Energy, Low Voltage 

Battery Chargers (Manufacturer Data) 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Avg. 

Operating Avg. 

Wtd. 

Avg. 

Consumers with 

Net No Net 

CSL UEC Price Cost LCC Savings Cost Impact Benefit Median Mean 

kWh 2009$ 2009$ 2009$ 2009$ % % % yrs. yrs. 

0 202.7 45.91 90.58 136.49 - - - - - -

1 159.6 59.09 72.76 131.85 2.08 10.0 56.9 33.1 2.4 8.1 

2 100.0 112.93 40.69 153.62 -11.07 48.4 40.5 11.1 6.4 7.7 

3 75.0 205.20 30.43 235.63 -93.07 99.9 0.0 0.1 17.2 42.2 

Table ES.3.38 LCC and PBP Results for Product Class 5: Medium Energy, Low Voltage 

Battery Chargers (Test/Teardown Data) 

CSL UEC 

kWh 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Price 

2009$ 

Avg. 

Operating 

Cost 

2009$ 

Avg. 

LCC 

2009$ 

Wtd. 

Avg. 

Savings 

2009$ 

Consumers with 

Median 

yrs. 

Mean 

yrs. 

Net 

Cost 

% 

No 

Impact 

% 

Net 

Benefit 

% 

0 202.7 45.91 112.90 158.81 - - - - - -

1 159.6 50.64 83.11 133.75 11.20 0.0 56.2 43.8 0.9 0.9 

Table ES.3.39 LCC and PBP Results for Product Class 7: High Energy Battery Chargers 

(Manufacturer Data) 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Avg. 

Operating Avg. 

Wtd. 

Avg. 

Consumers with 

Net No Net 

CSL UEC Price Cost LCC Savings Cost Impact Benefit Median Mean 

kWh 2009$ 2009$ 2009$ 2009$ % % % yrs. yrs. 

0 290.0 195.80 171.85 367.65 - - - - - -

1 250.0 219.13 148.15 367.28 0.10 29.7 50.0 20.3 5.8 5.4 

2 200.0 266.16 118.52 384.68 -12.07 64.2 30.1 5.7 7.8 7.7 

3 150.0 361.77 88.89 450.66 -78.04 100.0 0.0 0.0 12.6 13.6 

27 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

Table ES.3.40 LCC and PBP Results for Product Class 10: Low Energy, AC Out Battery 

Chargers (Manufacturer Data) 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Avg. 

Operating Avg. 

Wtd. 

Avg. 

Consumers with 

Net No Net 

CSL UEC Price Cost LCC Savings Cost Impact Benefit Median Mean 

kWh 2009$ 2009$ 2009$ 2009$ % % % yrs. yrs. 

0 19.6 5.93 11.07 17.00 - - - - - -

1 6.4 7.62 3.60 11.22 5.16 0.0 11.0 89.0 1.3 1.2 

2 4.0 8.08 2.26 10.34 6.04 0.0 0.0 100.0 1.4 1.3 

3 1.5 8.65 0.85 9.50 6.88 0.0 0.0 100.0 1.5 1.5 

Table ES.3.41 LCC and PBP Results for Product Class 10: Low Energy, AC Out Battery 

Chargers (Test/Teardown Data) 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Avg. 

Operating Avg. 

Wtd. 

Avg. 

Consumers with 

Net No Net 

CSL UEC Price Cost LCC Savings Cost Impact Benefit Median Mean 

kWh 2009$ 2009$ 2009$ 2009$ % % % yrs. yrs. 

0 19.6 5.93 11.07 17.00 - - - - - -

1 6.4 4.54 3.60 8.14 7.88 0.0 11.1 88.9 0.0 0.0 

DOE conducted sensitivity analyses to quantify the relationship between certain critical 

inputs to the life-cycle cost (LCC) analysis and the resultant weighted-average LCC savings for 

EPSs. These critical inputs were MSPs, product lifetimes, usage profiles, and loading points. By 

varying the critical inputs simultaneously, DOE calculated a low-savings case and a high-savings 

case for weighted-average LCC savings to compare with the reference case previously presented. 

The sensitivity analysis demonstrates that in the high-savings case all analyzed EPSs have at 

least one CSL with positive LCC savings. Table ES.3.42 presents a summary of the EPS LCC 

sensitivity analysis results, indicating whether LCC savings are positive or negative in 

comparison to the reference case. Table ES.3.43 presents the detailed results of the EPS LCC 

sensitivity analysis by CSL. 

28 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

 

Table ES.3.42 EPS Weighted-Average LCC Savings Sensitivity Analysis Summary 

Reference Case High Savings Case Low Savings Case 

2.5 W 

CSL 1 Positive 

No changes in sign 

(All CSLs are positive) 

CSL 4 is now negative 

No other changes in sign 

CSL 2 Positive 

CSL 3 Positive 

CSL 4 Positive 

18 W 

CSL 1 Positive 

No changes in sign 

(All CSLs are positive) 

CSL 4 is now negative 

No other changes in sign 

CSL 2 Positive 

CSL 3 Positive 

CSL 4 Positive 

60 W 

CSL 1 Positive 

No changes in sign CSL 2 is now negative 

No other changes in sign 

CSL 2 Positive 

CSL 3 Negative 

CSL 4 Negative 

120 W 

CSL 1 Negative CSL 1 is now positive 

No other changes in sign All CSLs are negative CSL 2 Positive 

CSL 3 Positive 

CSL 4 Negative 

Table ES.3.43 EPS Weighted-Average LCC Savings by CSL 

Reference 

Case 

2009$ 

High Savings 

Case 

2009$ 

Low Savings 

Case 

2009$ 

2.5 W 

CSL 1 0.19 0.19 015 

CSL 2 0.14 0.23 0.08 

CSL 3 0.13 0.25 0.06 

CSL 4 0.02 0.17 (0.06) 

18 W 

CSL 1 0.33 0.51 0.21 

CSL 2 0.96 1.27 0.65 

CSL 3 1.20 1.79 0.42 

CSL 4 1.13 2.04 (0.19) 

60 W 

CSL 1 0.07 0.12 0.00 

CSL 2 0.05 0.27 (0.26) 

CSL 3 (0.65) (0.13) (1.42) 

CSL 4 (1.78) (0.78) (3.30) 

120 W 

CSL 1 (0.02) 0.16 (0.15) 

CSL 2 0.05 0.63 (0.37) 

CSL 3 0.01 0.72 (0.51) 

CSL 4 (3.69) (1.39) (5.72) 

DOE also conducted sensitivity analyses in a manner similar to that it used for EPSs to 

quantify the relationship between certain critical inputs to the LCC analysis and the resultant 

weighted-average LCC savings for BCs. These critical inputs were MSPs, product lifetimes, and 

usage profiles. As explained earlier, DOE analyzed LCC results for both manufacturer data and 

test and teardown data. DOE adjusted MSPs, product lifetimes, and usage profiles for the 

manufacturer data. For the teardown results, DOE varied all the inputs except for the MSP, 

29 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

 

 

because the MSP was based on iSupplia teardowns of physical units, which did not have an 

associated uncertainty. By varying the critical inputs simultaneously, DOE calculated a lowsavings case and a high-savings case for weighted-average LCC savings to compare with the 

reference case presented above. Table ES.3.44 presents a summary of the BC LCC sensitivity 

analysis results, indicating whether LCC savings are positive or negative in comparison to the 

reference case. Table ES.3.45 presents the detailed results of the BC LCC sensitivity analysis by 

product class. 

Table ES.3.44 BC Weighted-Average LCC Savings Sensitivity Analysis Summary 

Manufacturer Data Test and Teardown Data 

Reference 

Case 

High Savings 

Case 

Low Savings 

Case 

Reference 

Case 

High Savings 

Case 

Low Savings 

Case 

PC 1 

CSL 1 Positive No changes in 

sign 

(All CSLs are 

positive) 

No changes in 

sign 

(All CSLs are 

positive) 

CSL 2 Positive No Data 

CSL 3 Positive 

PC 2 

CSL 1 Positive 

No changes in 

sign 

No changes in 

sign 

N/A 

Negative 

N/A 

No changes in 

sign 

(All CSLs are 

negative) 

No changes 

in sign 

(All CSLs are 

negative) 

CSL 2 Negative 

CSL 3 N/A 

PC 4 

CSL 1 Positive 

All CSLs are 

positive 

All CSLs are 

negative 

Positive 

Positive 

N/A 

No changes in 

sign 

(All CSLs are 

positive) 

No changes 

in sign 

(All CSLs are 

positive) 

CSL 2 Negative 

CSL 3 N/A 

PC 5 

CSL 1 Positive 

No changes in 

sign 

All CSLs are 

negative 

Positive 

N/A 

N/A 

No changes in 

sign 

(All CSLs are 

positive) 

No changes 

in sign 

(All CSLs are 

positive) 

CSL 2 Negative 

CSL 3 Negative 

PC 7 

CSL 1 Positive CSL 1 and 

CSL 2 are 

positive 

All CSLs are 

negative CSL 2 Negative No Data 

CSL 3 Negative 

PC 10 

CSL 1 Positive No changes in 

sign 

(All CSLs are 

positive) 

No changes in 

sign 

(All CSLs are 

positive) 

Positive 

N/A 

N/A 

No changes in 

sign 

(All CSLs are 

positive) 

No changes 

in sign 

(All CSLs are 

positive) 

CSL 2 Positive 

CSL 3 Positive 

a iSuppli is a DOE subcontractor tasked with disassembling various battery chargers and external power supplies and 

developing a high volume cost for the individual circuit elements. 

30 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

Table ES.3.45 BC Weighted-Average LCC Savings by Product Class 

Manufacturer Data (2009$) Test and Teardown Data (2009$) 

Reference 

Case 

High 

Case 

Low 

Case 

Reference 

Case 

High 

Case 

Low 

Case 

PC 1: Low E, 

Inductive 

CSL 1 0.93 0.94 0.89 

CSL 2 2.14 2.19 2.05 No Data 

CSL 3 2.90 2.98 2.78 

PC 2: Low E, 

Low V 

CSL 1 0.20 0.31 0.08 N/A N/A N/A 

CSL 2 (13.74) (11.47) (17.74) (0.90) (0.61) (1.21) 

CSL 3 N/A N/A N/A N/A N/A N/A 

PC 4: Low E, 

High V 

CSL 1 0.97 1.86 (0.23) 1.33 1.95 1.03 

CSL 2 (0.65) 1.07 (2.83) 1.74 2.64 1.35 

CSL 3 N/A N/A N/A N/A N/A N/A 

PC 5: Medium E, 

Low V 

CSL 1 2.08 2.99 (4.82) 11.20 N/A * 7.58 

CSL 2 (11.07) (6.49) (29.68) N/A N/A N/A 

CSL 3 (93.07) (77.74) (136.75) N/A N/A N/A 

PC 7: High E CSL 1 0.10 5.93 (6.83) 

CSL 2 No Data (12.07) 5.03 (32.69) 

CSL 3 (78.04) (41.27) (122.34) 

PC 10: Low E, 

AC Out 

CSL 1 5.16 5.34 4.93 7.88 N/A * N/A * 

CSL 2 6.04 6.28 5.74 N/A N/A N/A 

CSL 3 6.88 7.19 6.48 N/A N/A N/A * Inputs did not change from the reference case. See reference case data. 

Appendix 8B provides more details on the sensitivity analyses methodology and results. 

ES.3.8 Shipments Analysis 

The shipments analysis generates shipment forecasts and base case efficiency 

distributions for each of the product classes being considered in this preliminary analysis of 

standards for battery chargers and external power supplies. These outputs allow DOE to assess 

the scale of savings potential, in terms of the number of units that could be affected by potential 

standards. Outputs from the shipments analysis are inputs to the life-cycle cost analysis, national 

impact analysis, and manufacturer impact analysis. 

Chapter 9 provides more details on the methods, data, and assumptions used for the 

shipments analysis. 

ES.3.9 National Impact Analysis 

The national impact analysis (NIA) assesses the following impacts from potential energy 

efficiency standards: 

31 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

(1) the national energy savings (NES) attributable to each possible standard, calculated 

by combining unit energy savings (from the energy use analysis) with the number of units 

affected by a potential standard, which is itself a combination of the product’s estimated lifetime 

(from the market assessment), shipments and efficiency distributions (from the shipments 

analysis). Initial savings are calculated in site kWh, and then converted to source Btu. 

(2) the monetary value of those energy savings to consumers of the considered products, 

calculated by combining NES with forecast electricity prices. 

(3) the increased cost of the products because of standards, calculated by combining the 

unit improvement costs with the number of units affected by a standard, and 

(4) net present value (NPV) of total consumer costs and savings, calculated as the 

difference between the value of energy savings less increased product costs, discounted to the 

present. 

In order to determine the influence of inputs on the NIA, DOE conducted an NIA 

sensitivity analysis that mirrored the LCC sensitivity analysis. The results of the NIA sensitivity 

analysis are presented below and in chapter 10. 

To give some sense for the relative significance of various types of BCs and EPSs, DOE 

estimated the national aggregate annual energy consumption of products in several market 

segments. These estimates are shown in Table ES.3.46 for EPSs and Table ES.3.47 for BCs. 

When evaluated in the reference savings case, the EPSs and BCs that shipped in 2008 consume 

an estimated 2.2 billion kWh/yr and 3.4 billion kWh/yr of electricity, respectively. 

Table ES.3.46 Estimated National Annual Energy Consumption of External Power 

Supplies Shipped in 2008 

Product Class 

Annual Energy Consumption 

Site Energy 

(Million kWh) 

Primary Energy 

(Trillion Btu) 

Percent of 

Total 

A1: 0-10.25 W 251 3 11% 

A1: 10.25-39 W 930 10 42% 

A1: 39-90 W 582 6 26% 

A1: 90-250 W 186 2 8% 

A2 (DC Output, Low Voltage) 144 2 6% 

A3 (AC Output, Basic Voltage) 113 1 5% 

A4 (AC Output, Low Voltage) 17 0 1% 

All Class A EPSs 2,222 24 100% 

Note: Figures calculated using DOE’s estimates of the efficiency of products in the market in 2009. 

Individual values may not sum to totals due to rounding. 

32 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

Table ES.3.47 Estimated National Annual Energy Consumption of Battery Chargers 

Shipped in 2008 

Conversion 

Type 

Battery 

Energy Battery 

Voltage 

Class 

ID 

Annual Energy Consumption 

Site Energy 

(Million 

kWh) 

Primary 

Energy 

(Trillion Btu) 

Percent 

of Total 

AC-DC 

<100 Wh 

Inductive 

Connection 1 

47 1 1% 

<4 V 2 1,539 17 45% 

4<10 V 3 148 2 4% 

≥10 V 4 991 11 29% 

100-

3,000 Wh <20 V 5 

359 4 11% 

≥20 V 6 48 1 1% 

>3,000 Wh 7 55 1 2% 

DC-DC <9 V Input 8 80 1 2% 

≥9 V Input 9 15 0.2 <1% 

AC-AC 

AC Output 

from 

Battery 

10 

125 1 4% 

All Battery Chargers 3,408 37 100% 

Note: Figures calculated using DOE’s estimates of the efficiency of products in the market in 2009. 

Individual values may not sum to totals due to rounding. 

Chapter 10 provides more details on the methods, data, and assumptions used for the 

national impact analysis. 

ES.3.9.1 National Energy Savings Analysis 

DOE’s preliminary analysis finds that new standards for BCs and amended standards for 

EPSs could produce cumulative energy savings over the period of analysis of as much as 

3.5 quadrillion Btu (quads) and 1.5 quads, respectively, in the case where energy savings are 

maximized. In the case where consumer benefits are maximized, new standards for BCs and 

amended standards for EPSs could produce cumulative energy savings over the period of 

analysis of 1.4 quads and 1.0 quads, respectively. These totals assume reference case input 

values and manufacturer-derived cost data. 

Table ES.3.48, Table ES.3.49 and Table ES.3.50 show DOE’s estimates of national 

energy savings potential at each CSL for EPS and BC product classes. In each cell, results from 

the reference case are shown in the top of the cell, with results from the low and high cases 

shown in parentheses in the bottom of the cell. Savings in the low and high savings cases were 

only calculated for the representative product classes: EPS product class A1 and BC product 

33 

EERE-2008-BT-STD-0005 COMMENT 31
 

classes 2, 4, 5, 7, and 10. Because of the unavailability of data regarding the other classes, DOE 

took this more limited approach in its analysis. 

Table ES.3.48 National Energy Savings Potential from Amended Standards for Class A 

External Power Supplies (Trillion Btu) 

Product Class 

Standard Level Selected 

CSL 1 CSL 2 CSL 3 CSL 4 

A1: 0-10.25 W 57 

(46 to 58) 

114 

(99 to 142) 

144 

(127 to 180) 

158 

(140 to 202) 

A1: 10.25-39 W 132 

(119 to 145) 

319 

(287 to 352) 

504 

(453 to 555) 

643 

(578 to 710) 

A1: 39-90 W 34 

(31 to 43) 

137 

(128 to 167) 

232 

(217 to 286) 

374 

(345 to 466) 

A1: 90-250 W 10 

(9 to 15) 

35 

(32 to 54) 

42 

(38 to 64) 

88 

(78 to 137) 

A2 (DC Output, Low Voltage) 32 81 96 111 

A3 (AC Output, Basic Voltage) 26 64 101 128 

A4 (AC Output, Low Voltage) 4 7 9 10 

All Class A EPSs 296 

(267 to 325) 

756 

(697 to 866) 

1128 

(1041 to 

1291) 

1512 

(1389 to 

1763) 

Note: Individual values may not sum to totals due to rounding. 

34 

EERE-2008-BT-STD-0005 COMMENT 31
Table ES.3.49 National Energy Savings Potential from New Standards for Battery 

Chargers (Trillion Btu), Manufacturer Data 

Conversion 

Type 

Battery 

Energy Battery 

Voltage 

Class 

ID 

Standard Level Selected 

CSL 1 CSL 2 CSL 3 

AC-DC 

<100 

Wh 

Inductive 

Connection 1 22 52 71 

<4 V 2 395 

(337 to 421) 

1591 

(1271 to 1785) N/A 

4<10 V 3 59 206 N/A 

≥10 V 4 541 

(465 to 764) 

810 

(692 to 1144) N/A 

100-

3000 Wh <20 V 5 88 

(19 to 88) 

248 

(109 to 248) 

364 

(135 to 364) 

≥20 V 6 41 76 97 

>3000 

Wh 7 9 

(4 to 15) 

26 

(12 to 42) 

49 

(24 to 81) 

DC-DC <9 V Input 8 21 50 N/A 

≥9 V Input 9 5 14 N/A 

AC-AC 

AC Output 

from 

Battery 

10 176 212 249 

35 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

Table ES.3.50 National Energy Savings Potential from New Standards for Battery 

Chargers (Trillion Btu), Test and Teardown Data 

Conversion 

Type 

Battery 

Energy Battery 

Voltage 

Class 

ID 

Standard Level Selected 

CSL 1 CSL 2 CSL 3 

AC-DC 

<100 

Wh 

Inductive 

Connection 1 No Data 

<4 V 2 N/A 1536 

(1268 to 1727) N/A 

4<10 V 3 No Data 

≥10 V 4 542 

(476 to 770) 

812 

(720 to 1159) N/A 

100– 

3000 

Wh 

<20 V 5 107 

(63 to 107) N/A N/A 

≥20 V 6 No Data 

>3000 

Wh 7 No Data 

DC-DC <9 V Input 8 No Data 

≥9 V Input 9 No Data 

AC-AC 

AC Output 

from 

Battery 

10 825 

(715 to 1053) N/A N/A 

ES.3.9.2 Net Present Value Analysis 

DOE’s preliminary analysis finds that new standards for BCs and amended standards for 

EPSs would yield net consumer savings over the period of analysis of $4.5 billion and 

$3.4 billion, respectively, in the case where a CSL is selected for each product class to maximize 

consumer benefits. In the case where energy savings are maximized, standards would yield net 

consumer savings over the period of analysis of -$70 billion and $0.25 billion for BCs and EPSs, 

respectively. These totals assume reference case input values and manufacturer-derived cost 

data. 

Table ES.3.51, Table ES.3.52, Table ES.3.53, Table ES.3.54, Table ES.3.55 and Table 

ES.3.56 show the NPV results for the EPS and BC product classes at each CSL. In each cell, 

results from the reference case are shown in the top of the cell, with results from the low and 

high cases shown in parentheses in the bottom of the cell. Savings in the low and high savings 

cases were only calculated for the representative product classes: EPS product class A1 and BC 

product classes 1, 2, 4, 5, 7, and 10. As indicated earlier, data limitations restricted DOE’s ability 

to calculate parallel savings from other classes. 

36 

EERE-2008-BT-STD-0005 COMMENT 31
Table ES.3.51 Net Present Value of Amended Standards for Class A External Power 

Supplies at a 3 Percent Discount Rate (2009$ millions) 

Product Class Standard Level Selected 

CSL 1 CSL 2 CSL 3 CSL 4 

A1: 0-10.25 W 

332 

(261 to 

335) 

315 

(212 to 

496) 

322 

(202 to 

562) 

160 

(29 to 457) 

A1: 10.25-39 W 

637 

(391 to 

807) 

1663 

(1164 to 

2027) 

2155 

(1007 to 

2921) 

2186 

(281 to 

3402) 

A1: 39-90 W 90 

(24 to 172) 

117 

(-199 to 

442) 

-606 

(-1426 to 

96) 

-1785 

(-3415 to -

476) 

A1: 90-250 W -2 

(-27 to 47) 

18 

(-56 to 178) 

10 

(-81 to 205) 

-768 

(-1157 to -

183) 

A2 (DC Output, Low 

Voltage) 174 106 22 -136 

A3 (AC Output, Basic 

Voltage) 138 348 492 560 

A4 (AC Output, Low 

Voltage) 26 32 42 38 

Table ES.3.52 Net Present Value of Amended Standards for External Power Supplies at a 

7 Percent Discount Rate (2009$ millions) 

Product Class Standard Level Selected 

CSL 1 CSL 2 CSL 3 CSL 4 

A1: 0-10.25 W 

165 

(130 to 

164) 

138 

(88 to 224) 

133 

(75 to 247) 

40 

(-24 to 183) 

A1: 10.25-39 W 

311 

(180 to 

400) 

819 

(556 to 

1008) 

1035 

(422 to 

1439) 

1012 

(-10 to 

1658) 

A1: 39-90 W 41 

(6 to 82) 

29 

(-142 to 

195) 

-392 

(-836 to -

29) 

-1074 

(-1957 to -

393) 

A1: 90-250 W -3 

(-16 to 22) 

3 

(-37 to 84) 

-3 

(-52 to 96) 

-438 

(-649 to -

136) 

A2 (DC Output, Low 

Voltage) 86 37 -14 -104 

A3 (AC Output, Basic 

Voltage) 63 161 223 248 

A4 (AC Output, Low 

Voltage) 13 16 20 18 

37 

EERE-2008-BT-STD-0005 COMMENT 31
Table ES.3.53 Net Present Value of New Standards for Battery Chargers at a 3 Percent 

Discount Rate (2009$ millions), Manufacturer Data 

Conversion 

Type 

Battery 

Energy 

Battery 

Voltage 

Class 

ID 

Standard Level Selected 

CSL 1 CSL 2 CSL 3 

AC-DC 

<100 

Wh 

Inductive 

Connection 1 121 

(118 to 123) 

281 

(272 to 287) 

382 

(369 to 391) 

<4 V 2 1360 

(718 to 1654) 

-57441 

(-74744 to 

-48000) 

N/A 

4<10 V 3 -39 -3957 N/A 

≥10 V 4 1291 

(265 to 2988) 

-980 

(-3283 to 2023) N/A 

100– 

3000 

Wh 

<20 V 5 274 

(-213 to 306) 

-277 

(-1503 to -64) 

-4026 

(-6658 to 

-3293) 

≥20 V 6 0.05 -603 -2277 

>3000 Wh 7 7 

(-27 to 45) 

-37 

(-135 to 72) 

-315 

(-525 to -90) 

DC-DC <9 V Input 8 -552 -1970 N/A 

≥9 V Input 9 -80 -958 N/A 

AC-AC 

AC Output 

from 

Battery 

10 898 

(857 to 923) 

1056 

(1003 to 1089) 

1211 

(1142 to 

1253) 

38 

EERE-2008-BT-STD-0005 COMMENT 31
Table ES.3.54 Net Present Value of New Standards for Battery Chargers at a 7 Percent 

Discount Rate (2009$ millions), Manufacturer Data 

Conversion 

Type 

Battery 

Energy 

Battery 

Voltage 

Class 

ID 

Standard Level Selected 

CSL 1 CSL 2 CSL 3 

AC-DC 

<100 

Wh 

Inductive 

Connection 1 59 

(57 to 60) 

137 

(132 to 140) 

187 

(179 to 191) 

<4 V 2 641 

(310 to 783) 

-31855 

(-41224 to -

26790) 

N/A 

4<10 V 3 -40 -2,229 N/A 

≥10 V 4 555 

(31 to 1361) 

-762 

(-1967 to 696) N/A 

100– 

3000 

Wh 

<20 V 5 115 

(-124 to 132) 

-251 

(-866 to -134) 

-2349 

(-3699 to -

1948) 

≥20 V 6 -21 -370 -1,298 

>3000 Wh 7 0.2 

(-16 to 16) 

-30 

(-76 to 15) 

-191 

(-292 to -96) 

DC-DC <9 V Input 8 -308 -1,090 N/A 

≥9 V Input 9 -45 -529 N/A 

AC-AC 

AC Output 

from 

Battery 

10 425 

(402 to 438) 

498 

(469 to 516) 

569 

(531 to 592) 

39 

EERE-2008-BT-STD-0005 COMMENT 31
Table ES.3.55 Net Present Value of New Standards for Battery Chargers at a 3 Percent 

Discount Rate (2009$ millions), Test and Teardown Data 

Conversion 

Type 

Battery 

Energy 

Battery 

Voltage 

Class 

ID 

Standard Level Selected 

CSL 1 CSL 2 CSL 3 

AC-DC 

<100 

Wh 

Inductive 

Connection 1 No Data 

<4 V 2 N/A -2638 

(-4342 to -1467) N/A 

4<10 V 3 No Data 

≥10 V 4 

2351 

(1949 to 

3744) 

3225 

(2661 to 5345) N/A 

100– 

3000 

Wh 

<20 V 5 570 

(293 to 570) N/A N/A 

≥20 V 6 No Data 

>3000 Wh 7 No Data 

DC-DC <9 V Input 8 No Data 

≥9 V Input 9 No Data 

AC-AC 

AC Output 

from 

Battery 

10 1232 N/A N/A 

Table ES.3.56 Net Present Value of New Standards for Battery Chargers at a 7 Percent 

Discount Rate (2009$ millions), Test and Teardown Data 

Conversion 

Type 

Battery 

Energy 

Battery 

Voltage 

Class 

ID 

Standard Level Selected 

CSL 1 CSL 2 CSL 3 

AC-DC 

<100 

Wh 

Inductive 

Connection 1 No Data 

<4 V 2 N/A -1845 

(-2689 to -1304) N/A 

4<10 V 3 No Data 

≥10 V 4 1136 

(950 to 1773) 

1539 

(1280 to 2509) N/A 

100– 

3000 

Wh 

<20 V 5 269 

(135 to 269) N/A N/A 

≥20 V 6 No Data 

>3000 Wh 7 No Data 

DC-DC <9 V Input 8 No Data 

≥9 V Input 9 No Data 

40 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

AC-AC 

AC Output 

from 

Battery 

10 608 N/A N/A 

ES.3.10 Preliminary Manufacturer Impact Analysis 

A preliminary manufacturer impact analysis (MIA) assesses the potential impacts of 

energy conservation standards on manufacturers, such as effects on expenditures for capital 

conversion, marketing costs, shipments, and research and development costs. Potential impacts 

might lead to changes in manufacturing practices for battery chargers and external power 

supplies. DOE identified potential impacts through interviews with manufacturers and other 

interested parties. 

Manufacturers and other parties identified eight general areas of concern for external 

power supplies and battery chargers. Relating to standards for external power supplies, 

manufacturers and other parties identified four general areas of concern: (1) impacts on 

shipments, (2) timing of standards, (3) efficiency levels, and (4) regulatory approval. 

Relating to standards for battery chargers, manufacturers and other parties identified four 

general areas of concern: (1) conversion costs, (2) efficiency as a selling point, (3) profit 

margins, and (4) regulatory burden. See chapter 12 of the preliminary TSD for details. 

ES.3.11 Other Analyses 

The remaining chapters of the preliminary TSD address the analyses to be performed for the 

notice of proposed rulemaking (NOPR): 

The life-cycle cost analysis for subgroups evaluates the effects of energy conservation 

standards on various national subgroups (chapter 11). 

The utility impact analysis examines impacts of energy conservation standards on the 

generation capacity of electric utilities (chapter 13). 

The employment impact analysis examines the effects of energy conservation standards 

on national employment (chapter 14). 

The environmental assessment examines the effects of energy conservation standards on 

various airborne emissions. 

The regulatory impact analysis examines the national impacts of non-regulatory 

alternatives to mandatory energy conservation standards. 

ES.4 ISSUES ON WHICH DOE SEEKS PUBLIC COMMENT 

DOE is interested in receiving comments on all aspects of this preliminary analysis. DOE 

especially invites comments and data to improve this preliminary analysis, including data or 

information that will respond to the following questions or concerns that were raised in response 

to the framework document and in preparation of the preliminary TSD. 

41 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

ES.4.1 Criteria for Identifying Charge Control in Wall Adapters 

DOE is considering adopting the EPA criteria for establishing the presence of charge 

control in a wall adapter, which are: (1) not having batteries or battery packs that physically 

attach directly (including those that are removable) to the power supply unit or (2) not having a 

battery chemistry or type selector switch AND an indicator light or state of charge meter (e.g., a 

product with a type selector switch AND a state of charge meter is excluded from this 

specification; a product with only an indicator light is still covered by this specification). DOE 

welcomes comment on the appropriateness of these criteria. This issue is discussed in chapter 3 

of the preliminary TSD. 

ES.4.2 Design Options for Battery Chargers and External Power Supplies 

DOE requests comment and data regarding additional design options or variants of the 

considered design options that can increase the range of considered efficiency improvements for 

either BCs or EPSs, including design options that may not yet be found in the market. 

ES.4.3 Product Classes for Battery Chargers 

DOE seeks comment on its battery charger product classes. In particular DOE seeks 

comment on its decision to group BCs for both power tools and notebook computer into the same 

low energy, high voltage product class. 

ES.4.4 Dissimilarities Between Low Energy, High Voltage Battery Chargers 

The low energy, high voltage product class includes both power tools and notebook 

computers. Although these two products are shifting from nickel to lithium-ion batteries and 

using more similar charge rates, DOE is still aware that differences between BCs for the two 

products may exist. DOE welcomes comment on any dissimilarities between BCs for these two 

types of low energy, high voltage products, and how best to address them in the analysis, e.g., 

through the creation of additional product classes. 

ES.4.5 Scaling Within Battery Charger Product Classes 

During interviews, some manufacturers suggested using the EPS ENERGY STAR 

specification equations to relate output power to efficiency. Both BCs and EPSs are power 

conversion circuits with the same general designs and components, and this method is already 

being used in the EPS engineering analysis. DOE seeks comments on using the EPS ENERGY 

STAR curve to scale the active-mode efficiency of BCs. 

ES.4.6 Medium Energy, Low Voltage Representative Unit for BCs 

DOE seeks comment on whether the marine charger is the most appropriate application 

to focus its representative-unit analysis for the medium energy, low voltage product class. 

42 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

 

ES.4.7 EPS Representative Units 

DOE selected EPS representative units by focusing on popular units in the market, which 

was straightforward for most representative units, except the low-power representative unit. 

Although DOE considered a 5-watt representative unit because of its prevalence, DOE instead 

selected a 2.5-watt representative unit because it belonged to the representative product class A1 

whereas the 5-watt EPS was in the non-analyzed product class A2. DOE invites comment on this 

approach in general and on whether to perform a detailed analysis for 5-watt, 5-volt EPSs in 

particular. See chapter 5 of the preliminary TSD for more detail. 

ES.4.8 EPS Max-Tech Value for 2.5-Watt Representative Unit 

DOE verified the reasonableness of the aggregated manufacturer max-tech data which it 

used to create curve fit equations for CSL 4 (max-tech). To that end, DOE’s subject matter 

experts (SMEs) reviewed the data and confirmed that the data fell within the expected ranges of 

efficiencies based on their extensive experience with EPSs, other than the max-tech value for the 

2.5W EPSs. The SMEs believe that 2.5W EPSs may be able to achieve a max tech efficiency of 

80 percent rather than the 74.0 percent efficiency derived from manufacturers. DOE seeks 

comment on the 2.5W max tech efficiency value used. DOE also seeks comment on the cost of 

an 80 percent-efficient EPS, which it would need in order to use that as the max-tech efficiency 

level for 2.5W EPSs in the NOPR. 

ES.4.9 Efficiency Metrics for Multiple-Voltage EPSs 

On April 2, 2010, DOE proposed a test procedure for multiple-voltage EPSs that would 

yield five values: no-load power consumption as well as efficiency at 25 percent, 50 percent, 75 

percent, and 100 percent of maximum load. 75 FR 16958. If DOE finalizes that proposal, DOE 

would then propose to integrate the four efficiency values into an average efficiency metric in 

the standard. Specifically, DOE proposes to use the no-load power consumption and an average 

of the four efficiency values as metrics to set candidate standard levels for multiple-voltage 

EPSs, similar to those set for single-voltage EPSs. Alternatively, DOE is also considering 

approaches to integrate the four active mode measurements in a way that may better indicate the 

typical efficiency of multiple-voltage EPSs during typical use. For instance, DOE could average 

only the efficiency values at 50 percent and 75 percent, since those values are closest to the 

operating conditions described by a stakeholder (Microsoft, EERE‐2008‐BT‐TP‐0004 No.8 at p. 

1-2). Overall, DOE faces the same challenge with multiple-voltage EPSs as it does with singlevoltage EPSs: products change continuously, so the test metric should be robust enough to be 

valid for all applicable products. DOE is seeking stakeholder comment on alternative methods 

for using the five metrics to set candidate standard levels for EPSs. 

ES.4.10 Representative Product Classes and Units for MADB EPSs 

DOE chose to treat only MADB EPS product class B1 as representative because there are 

significant similarities between the MADB product classes. Specifically, the MADB EPS 

product classes have the same product class structure as the Class A EPS product classes, as 

explained in chapter 3. To that end, DOE applied the same structure as Class A EPS for the 

MADB EPS representative product classes and representative units. Since DOE can apply all 

43 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

 

 

 

 

Class A EPS analysis to MADB EPSs, it intends also to include a 120-watt representative unit. 

However, DOE has not identified an associated application for that unit. DOE is seeking 

stakeholder comment on any applications that use a 120-watt MADB EPS and whether to 

analyze that unit if it cannot identify any associated applications. 

ES.4.11 Baseline Candidate Standard Level of Efficiency for Medical and MADB EPSs 

In the determination analysis DOE defined the efficiency values for each CSL based on 

existing efficiency levels in the market, test data and manufacturer data. For the NOPR, DOE is 

considering gathering more data for medical and MADB EPSs with which to develop specific 

efficiency values for the baseline CSL 0. This would allow DOE to characterize the benefits of 

higher standards to consumers purchasing EPSs with efficiencies below EISA requirements. 

However, DOE believes that consumers of medical and MADB EPSs with efficiencies below 

EISA constitute a small and shrinking part of the market, based on information from 

manufacturer interviews. Therefore, DOE is also considering accounting for the lowest part of 

the market in the “EISA qualified” CSL as a simplifying alternative. Under this alternate 

approach, there would be no difference between CSL 0 for Class A EPSs and CSL 0 for medical 

and MADB EPSs in the engineering analysis. DOE is seeking stakeholder comment on which 

approach to pursue or whether standard levels for medical EPSs should continue to be considered 

in light of their critical lifesaving role. 

ES.4.12 Scaling for EPS Representative Units and CSLs 

DOE developed scaling relationships that it used both to analyze EPS representative unit 

data as well as to scale CSLs from product class A1 to other product classes. In general, the 

scaling methods for representative unit data were detailed whereas the scaling methods for CSLs 

were simpler. For the representative unit data, DOE adopted the more detailed approach because 

the detailed methods provide enhanced accuracy, which was paramount as it was the basis for 

later analyses, including the LCC and NIA. For the CSL equations, DOE adopted the simpler 

approach so that stakeholders could more easily evaluate the CSLs. DOE is seeking comment on 

these approaches in general and whether to develop more detailed CSL equations in particular. 

To analyze representative unit data, DOE developed and applied the following scaling 

relationships: 

Efficiency by nameplate output power 

Efficiency by nameplate output voltage 

Efficiency by output cord length 

Cost by nameplate output power 

Cost by output cord length 

Markups to MSP 

DOE did not develop scaling relationships related to no-load mode power consumption or 

cost by production volume. DOE is seeking comment on the scaling relationships in general and 

its decision on which scaling relationships to develop. 

44 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

ES.4.13 Cost Estimates for Product Classes not Fully Analyzed 

DOE developed estimates of incremental costs for BC product classes not fully analyzed 

using the extrapolation methods described in chapter 5. For EPS product classes not fully 

analyzed, DOE used the cost estimates it developed for the representative units as follows: for 

product classes A2 and A4 DOE used engineering results for the 2.5 W representative unit, 

and for product class A3 DOE used engineering results for the 18 W representative unit. The 

underlying assumption is that the incremental costs associated with improving the efficiency of 

products in a non-analyzed product class are equal to those associated with improving the 

corresponding representative unit. DOE invites comment on these approaches. 

ES.4.14 Market Data 

DOE based its estimates of BC and EPS shipments on the estimated shipments of the 

applications they power. DOE relied on published reports, comments from stakeholders, and its 

own estimates to estimate shipments for each application. DOE also conducted a market survey 

of over 50 common applications to determine the prevalence of BCs and EPSs and their 

characteristics. DOE used these characteristics to estimate BC and EPS shipments for each 

product class and representative unit. DOE seeks comments on its estimates of BC and EPS 

shipments for each application and also the shipments in each product class and for each 

representative unit. 

ES.4.15 Product Lifetimes 

DOE developed estimates of the average lifetime of each BC and EPS application 

examined in the preliminary analysis. DOE welcomes comment on these estimates and on the 

use of individual application lifetimes to generate LCC results. In particular, DOE seeks 

comment on the accuracy of using the distribution of lifetimes from various applications as 

opposed to sampling from a continuous distribution of lifetime values for a given representative 

unit. 

ES.4.16 Estimated Markups and Incremental Markup Assumptions 

The confidential nature of the markups applied to BCs and EPSs necessitated that DOE 

estimate markups using data from publicly available corporate financial filings. DOE seeks 

comment on the accuracy of its estimated markups and specifically seeks comment on the 

assumptions and methods used to calculate markups applied to baseline product costs (baseline 

markups) and markups applied to cost increases resulting from standards (incremental markups). 

ES.4.17 Sensitivity Analysis Methodology and Results 

DOE conducted sensitivity analyses to quantify the relationship between certain critical 

inputs to the life-cycle cost (LCC) analysis and the resultant weighted-average LCC savings for 

BCs and EPSs. DOE conducted a similar analysis as part of the national impact analysis. DOE 

seeks comment on the sensitivity analysis results and methodology. 

45 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

ES.4.18 Use in the Commercial Sector 

DOE recognizes that some BC and EPS applications under consideration in this 

rulemaking, notably notebook computers, are also used extensively in the commercial sector. 

The preliminary analysis does not differentiate between applications used in the commercial and 

residential sectors. DOE intends to examine the extent to which applications are used in the 

commercial sector during the NOPR stage of the analysis. DOE requests comments on the nature 

of the commercial share of application shipments, and the BC and EPS shipments that are made 

for those applications in the commercial sector. DOE also seeks comment on how usage profiles 

differ between residential and commercial users. DOE also recognizes that many portable BC 

applications, such as MP3 players and mobile phones, may be sold to residential users but 

charged in the commercial sector and thus incur costs associated with commercial utility rates. 

DOE proposes to ignore usage of residential products in the commercial sector in its energy cost 

savings estimations. DOE seeks comments on this proposal. 

ES.4.19 Prospects for Substitution in Response to Standards 

DOE assumed that prescribing a standard for BCs and EPSs will not result in competing 

technologies being substituted for them. Competing technologies include fuel cells, internal 

power supplies (IPS), primary batteries, Universal Serial Bus (USB) systems, and others. DOE 

believes that because application and device portability is important to consumers they will 

generally not substitute competing technologies for BCs. DOE addresses the use of USB power 

for BC applications, but requests comments on the degree to which an amended EPS standard 

might cause USB power to be substituted for EPS power. DOE also seeks comment on its 

assumption that substitution to other technologies will not occur in response to BC and EPS 

standards. 

ES.4.20 Usage Profiles 

DOE developed usage profiles to help estimate the energy consumption of BCs and EPSs 

and the energy savings potential of standards for those products. EPS usage profiles consist of 

time spent in active and no-load mode. Because an application can demand different levels of 

power, time in active mode was further divided by application state. Each application state was 

associated with a loading point, expressed as a percentage of nameplate output power. In 

chapter 7 of the preliminary TSD, DOE identified five loading points to apply to applications if 

test data were not available. DOE seeks comments on the usage profiles and loading points used 

for each EPS application. BC usage profiles consist of time spent in active, maintenance, nobattery, and off mode and the number of complete charge cycles completed over 24 hours. 

Application-specific BC usage profiles were developed for each application. DOE welcomes 

comment on all of these usage profiles. 

ES.4.21 Selecting Battery Charger Usage Profiles for Use in Determining Compliance 

with Standards 

To create an integrated energy performance metric for BCs requires that DOE identify a 

single usage profile for each product class. DOE seeks comment on how these usage profiles 

should be determined. 

46 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

ES.4.22 Shipment Trends 

In forecasting future shipments of BCs and EPSs, DOE assumed that current per-capita 

consumption of BCs and EPSs would remain constant. In other words, shipment growth is set 

equal to expected population growth during the next 33 years. DOE seeks comment on this 

assumption. 

ES.4.23 Base Case Efficiency Distributions 

To estimate what proportion of the BC and EPS markets would be affected by a standard 

at a particular level, DOE developed a base case efficiency forecast. Based on a consideration of 

several factors discussed in chapter 9, DOE forecasts modest improvement in the efficiency of 

Class A EPSs between now and 2013 and no improvement thereafter (in the absence of amended 

Federal standards). DOE forecasts no improvement in BC efficiency between now and 2013 

because it identified no significant drivers of efficiency. DOE welcomes comment on this 

forecast for use in calculating NES and NPV. 

ES.4.24 Quantifying Non-Consumer Benefits 

DOE acknowledges that there may be certain benefits resulting from the improved 

efficiency of BCs and EPSs that are not captured directly by the products' users. These include 

both environmental and energy security-related externalities that are not reflected in energy 

prices, such as reduced emissions of greenhouse gases and reduced use of fossil fuels for 

electricity generation. DOE invites comments on the nature and magnitude of such benefits. 

ES.4.25 Impact on Manufacturers 

DOE requests comment on its identification of key issues and requests data and 

information from interested parties that can assist in evaluating the potential impact of standards 

on manufacturers presented in chapter 12. 

ES.4.26 Cumulative Regulatory Burdens 

DOE recognizes and seeks to mitigate the overlapping effects on manufacturers of new or 

amended DOE standards and other regulatory actions affecting the same equipment. DOE will 

analyze and consider the impact on manufacturers of multiple, product-specific regulatory 

actions in the NOPR. DOE invites comment on how regulations applicable to BCs and EPSs may 

contribute to manufacturers’ cumulative regulatory burden. DOE also requests information on 

the cost of low- and high-efficiency BCs and EPSs that are expected to be compliant with these 

regulations so that DOE can assess how these requirements may affect payback calculations. 

ES.4.27 Valuing Airborne Emission Reductions 

DOE will conduct an environmental assessment as part of the next phase of the standards 

rulemaking, the NOPR. The primary environmental effects of energy conservation standards for 

BCs and EPSs are to reduce power plant emissions resulting from reduced consumption of 

electricity. DOE will assess these environmental effects by using NEMS-BT to provide key 

inputs to its analysis. The portion of the environmental assessment that will be produced by 

47 

EERE-2008-BT-STD-0005 COMMENT 31
NEMS-BT considers carbon dioxide (CO2), sulfur dioxide (SO2), nitrogen oxides (NOX), and 

mercury (Hg). DOE also plans to monetize the emission reductions due to standards consistent 

with methods used in recent DOE standards rulemakings pertaining to commercial clothes 

washers and other consumer products and commercial equipment. For example, in the case of 

CO2, the most recent interagency estimates of the potential global benefits resulting from 

reduced CO2 emissions in 2010 were $4.7, $21.4, $35.1, and $64.9 per metric ton in 2007 

dollars. DOE invites comment on possible approaches to monetizing the emission reductions 

expected to result from energy conservation standards. 

48 

EERE-2008-BT-STD-0005 COMMENT 31
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CHAPTER 1 INTRODUCTION 

TABLE OF CONTENTS 

1.1 Document Purpose .......................................................................................... 1-1

1.2 History of Battery Charger and External Power Supply Rulemakings ........... 1-1

1.3 Process for Setting Energy Conservation Standards ....................................... 1-3

1.4 Structure of the Document .............................................................................. 1-6

LIST OF TABLES 

TABLE 1-1 ANALYSES BY RULEMAKING STAGE ............................................................ 1-5

EERE-2008-BT-STD-0005 COMMENT 31
1-1

CHAPTER 1 INTRODUCTION 

1.1 DOCUMENT PURPOSE 

This preliminary technical support document (TSD) is a stand-alone report that presents 

the technical analyses that the U.S. Department of Energy (DOE) has conducted in preparation 

for setting energy conservation standards for battery chargers (BCs) and external power supplies 

(EPSs). The public is invited to comment on these analyses, either in writing or orally at a public 

meeting on October 13, 2010. Details about the public meeting and instructions for submitting 

written comments are contained in the notice of public meeting (NOPM) published in the 

Federal Register on September 15, 2010. DOE will review the comments it receives and revise 

and update these analyses prior to publishing a notice of proposed rulemaking (NOPR) in the 

Federal Register. 

1.2 HISTORY OF BATTERY CHARGER AND EXTERNAL POWER SUPPLY 

RULEMAKINGS 

Title III of the Energy Policy and Conservation Act (EPCA) (42 U.S.C. 6291, et seq.) sets 

forth a variety of provisions designed to improve energy efficiency. Part A of Title III (42 U.S.C. 

6291–6309) establishes the “Energy Conservation Program for Consumer Products Other Than 

Automobiles.” The consumer products subject to this program (referred to as “covered 

products”) include BCs and EPSs. Section 135 of the Energy Policy Act of 2005 (EPACT 2005), 

Pub. L. 109-58, amended sections 321 and 325 of EPCA by inserting definitions for BCs and 

EPSs and directing the Secretary of Energy to carry out three activities: (1) establish test 

procedures, (2) hold a scoping workshop to discuss plans for developing energy conservation 

standards, and (3) conduct a determination analysis for energy conservation standards for BCs 

and EPSs. (42 U.S.C. 6295(u)) 

DOE complied with the first of these requirements by publishing the test procedure final 

rule on December 8, 2006. 71 FR 71340. This rule included definitions and test procedures for 

BCs and EPSs. DOE codified a test procedure for BCs in Title 10 of the Code of Federal 

Regulations (CFR), Part 430, Subpart B, Appendix Y (“Uniform Test Method for Measuring the 

Energy Consumption of Battery Chargers”) and a test procedure for EPSs in 10 CFR Part 430, 

Subpart B, Appendix Z (“Uniform Test Method for Measuring the Energy Consumption of 

External Power Supplies”). 

Complying with the second requirement, DOE then published a NOPM and availability 

of documentation for public review on December 29, 2006. 71 FR 78389. DOE made two 

documents available on its website: “Plans for Developing Energy Conservation Standards for 

Battery Chargers and External Power Supplies” and “The Current and Future Market for Battery 

Chargers and External Power Supplies.” The public meeting, called a “Scoping Workshop,” was 

held at DOE’s Forrestal Building in Washington, DC, on January 24, 2007. As EPACT 2005 

required, the workshop focused on DOE’s plans for developing energy conservation standards 

for BCs and EPSs. Information pertaining to the scoping workshop is available on DOE’s 

website at: 

www.eere.energy.gov/buildings/appliance_standards/residential/battery_external_det_2006.html.

EERE-2008-BT-STD-0005 COMMENT 31
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Regarding the third requirement, the President signed into law the Energy Independence 

and Security Act of 2007 (EISA 2007), Pub. L. 110-140, on December 19, 2007, amending 

sections 321, 323, and 325 of EPCA. These amendments required significant changes to the 

determination analysis DOE had been conducting. Sections 301, 309, and 310 of EISA 2007 

made several changes to EPCA related to BCs and EPSs. 

Section 301 of EISA 2007 amended section 321 of EPCA by modifying definitions 

concerning EPSs. EPACT 2005 had amended EPCA to define an EPS as “an external power 

supply circuit that is used to convert household electric current into DC current or lower-voltage 

AC current to operate a consumer product.”a(42 U.S.C. 6291(36)(A)) Section 301 of EISA 2007 

further amended this definition by creating a subset of EPSs called Class A EPSs. EISA 2007 

defined this subset as those EPSs that, in addition to meeting several other requirements common 

to all EPSs, are “able to convert to only 1 AC or DC output voltage at a time” and have 

“nameplate output power that is less than or equal to 250 watts.”b

(42 U.S.C. 6291(36)(C)(i)) 

Section 301 also amended EPCA to establish minimum standards for Class A EPSs, 

which became effective on July 1, 2008 (42 U.S.C. 6295(u)(3)(A)), and directed DOE to publish 

a final rule by July 1, 2011, to determine whether to amend these standards. (42 U.S.C. 

6295(u)(3)(D)) Section 301 further directed DOE to issue a final rule that prescribes energy 

conservation standards for BCs or determine that no “standard is technically feasible or 

economically justified.” (42 U.S.C. 6295(u)(1)(E)(i)(II)) 

In satisfaction of this requirement, DOE is bundling BCs and Class A EPSs together in a 

single rulemaking proceeding to consider appropriate energy conservation standards for these 

products. DOE published the “Notice of Public Meeting and Availability of Framework 

Document for Battery Chargers and External Power Supplies” on June 4, 2009. 74 FR 26816. 

DOE then held a public meeting to receive comment on the framework documentc

on July 16, 

2009 (hereafter referred to as the framework document public meeting). The present preliminary 

analysis represents the next stage in the rulemaking process. 

Section 309 of EISA 2007 further amended section 325(u)(1)(E) of EPCA, instructing 

DOE to issue no later than two years after EISA 2007's enactment a final rule “that determines 

whether energy conservation standards shall be issued for external power supplies or classes of 

external power supplies.” (42 U.S.C. 6295(u)(1)(E)(i)(I)) However, as section 301 of EISA 

simultaneously set standards for Class A EPSs, DOE interprets sections 301 and 309 jointly as a 

requirement to determine, no later than December 19, 2009, whether additional energy 

conservation standards shall be issued for EPSs that are outside the scope of the current Class A 

standards, e.g., multiple-voltage EPSs. DOE determined that standards are warranted for non-

 

a The terms “AC” and “DC” refer to the polarity (i.e., direction) and amplitude of current and voltage associated 

with electrical power. For example, a household wall socket supplies alternating current (AC), which varies in 

amplitude and reverses polarity. In contrast, a battery or solar cell supplies direct current (DC), which is constant in 

both amplitude and polarity. 

b

 EISA 2007 defines a Class A EPS as an EPS that converts AC line voltage to only 1 lower AC or DC output, is 

intended to be used with a separate end-use product, is in a different enclosure from the end-use product, is wired to 

the end-use product, and has rated output power that is less than 250 watts. (42 U.S.C. 6291(36)(C)(i)) 

c

“Energy Conservation Standards Rulemaking for Battery Chargers and External Power Supplies.” May 2009. 

Available at: 

http://www1.eere.energy.gov/buildings/appliance_standards/residential/pdfs/bceps_frameworkdocument.pdf

EERE-2008-BT-STD-0005 COMMENT 31
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Class A EPSs in a final rule published on May 14, 2010. 75 FR 27170. Standards for non-Class 

A EPSs are thus being considered within the present rulemaking process. 

Finally, section 310 of EISA 2007 amended section 325 of EPCA to establish definitions 

for active mode, standby mode, and off mode. (42 U.S.C. 6295(gg)(1)(A)) This section also 

directed DOE to amend its existing test procedures by December 31, 2008, to measure the 

energy consumed in standby mode and off mode for both BCs and EPSs. (42 U.S.C. 

6295(gg)(2)(B)(i)) Further, it authorized DOE to amend, by rule, any of the definitions for 

active, standby, and off mode. (42 U.S.C. 6295(gg)(2)(A)) The Department presented its 

amendments during a public meeting on September 12, 2008 (hereafter referred to as the standby 

and off mode test procedure public meeting) and published them in the Test Procedures for 

Battery Chargers and External Power Supplies (Standby Mode and Off Mode) Final Rule on 

March 27, 2009. 74 FR 13318. 

1.3 PROCESS FOR SETTING ENERGY CONSERVATION STANDARDS 

Under EPCA, when DOE studies new or amended standards, it must consider, to the 

greatest extent practicable, the following seven factors: 

(1) the economic impact of the standard on the manufacturers and consumers of the 

products subject to the standard; 

(2) the savings in operating costs throughout the estimated average life of the products 

compared to any increase in the prices, initial costs, or maintenance expenses for the 

products that are likely to result from the imposition of the standard; 

(3) the total projected amount of energy savings likely to result directly from the 

imposition of the standard; 

(4) any lessening of the utility or the performance of the covered products likely to result 

from the imposition of the standard; 

(5) the impact of any lessening of competition, as determined in writing by the Attorney 

General, that is likely to result from the imposition of the standard; 

(6) the need for national energy conservation; and 

(7) other factors the secretary considers relevant. (42 U.S.C. 6295(o)(2)(B)(i)) 

Other statutory requirements are set forth in 42 U.S.C. 6295(o)(1)–(2)(A), (2)(B)(ii)–(iii), 

and (3)–(4). 

 

DOE considers the participation of interested parties a very important part of the process 

for setting energy conservation standards. Through formal public notifications (i.e., Federal 

Register notices), DOE encourages the participation of all interested parties during the comment 

period in each stage of the rulemaking. Beginning with the framework document and during 

EERE-2008-BT-STD-0005 COMMENT 31
1-4

subsequent comment periods, interactions among interested parties provide a balanced 

discussion of the information that is required for the standards rulemaking.

Before DOE determines whether to adopt a proposed energy conservation standard, it 

must first solicit comments on the proposed standard. (42 U.S.C. 6313(a)(6)(B)(i)) Any new or 

amended standard must be designed to achieve significant additional conservation of energy and 

be technologically feasible and economically justified. (42 U.S.C. 6313(a)(6)(A)) To determine 

whether economic justification exists, DOE must review comments on the proposal and 

determine that the benefits of the proposed standard exceed its burdens to the greatest extent 

practicable, weighing the seven factors listed above. (42 U.S.C. 6295 (o)(2)(B)(i)) 

After the publication of the framework document, the energy conservation standards 

rulemaking process involves three additional public notices that DOE publishes in the Federal 

Register. The first of the rulemaking notices is a NOPM, which is designed to publicly vet the 

models and tools used in the preliminary rulemaking and to facilitate public participation before 

the NOPR stage. The second notice is the NOPR, which presents a discussion of comments 

received in response to the NOPM and the preliminary analyses and analytical tools; analyses of 

the impacts of potential new or amended energy conservation standards on consumers, 

manufacturers, and the Nation; DOE’s weighting of these impacts; and the proposed energy 

conservation standards for each product. The third notice is the final rule, which presents a 

discussion of the comments received in response to the NOPR, the revised analyses, DOE’s 

weighting of these impacts, the amended energy conservation standards DOE is adopting for 

each product, and the effective dates of the amended energy conservation standards. 

DOE published the “Notice of Public Meeting and Availability of the Framework 

Document” on June 4, 2009. 74 FR 26816. The framework document, Energy Conservation 

Standards Rulemaking Framework Document for Battery Chargers and External Power Supplies, 

describes the procedural and analytical approaches DOE anticipated using to evaluate the 

establishment of new or amended energy conservation standards for these products. This 

document is available at: 

www.eere.energy.gov/buildings/appliance_standards/residential/pdfs/bceps_frameworkdocumen

t.pdf.

Subsequently, DOE held a public meeting on July 16, 2009 to discuss procedural and 

analytical approaches to the rulemaking. In addition, DOE used the public meeting to inform and 

facilitate the involvement of interested parties in the rulemaking process. The analytical 

framework presented at the public meeting described the different analyses, such as the 

engineering analysis and the consumer economic analyses (i.e., the life-cycle cost (LCC) and 

payback period (PBP) analyses), the methods proposed for conducting them, and the 

relationships among the various analyses. 

EERE-2008-BT-STD-0005 COMMENT 31
1-5

Table 1-1 Analyses by Rulemaking Stage 

Preliminary NOPR Final Rule

Market and technology assessment   

Screening analysis   

Engineering analysis   

Energy use characterization   

Product price determination   

Life-cycle cost and payback period analyses   

Life-cycle cost subgroup analysis  

Shipments analysis   

National impact analysis   

Preliminary manufacturer impact analysis 

Manufacturer impact analysis  

Utility impact analysis  

Employment impact analysis  

Environmental assessment  

Regulatory impact analysis  

During the July 2009 public meeting, interested parties commented about numerous 

issues relating to the analyses listed in Table 1-1. Comments from interested parties submitted 

during the framework document comment period elaborated on the issues raised during the 

public meeting. DOE attempted to address these issues as part of its preliminary analyses and 

summarized the comments and DOE’s responses in chapter 2 of the TSD.

As part of the information gathering and sharing process, DOE interviewed BC and EPS 

manufacturers and those who make associated end-use consumer products. DOE selected 

companies that represented production of all types of products, ranging from small to large 

manufacturers. DOE had four objectives for these interviews: (1) solicit manufacturer feedback 

on the draft inputs to the engineering analysis; (2) solicit feedback on topics related to the 

preliminary manufacturer impact analysis; (3) provide an opportunity, early in the rulemaking 

process, for manufacturers to express their concerns to DOE; and (4) foster cooperation between 

manufacturers and DOE. 

DOE incorporated the information gathered during these interviews into its engineering 

analysis (chapter 5) and its preliminary manufacturer impact analysis (chapter 12). Following the 

publication of the preliminary analyses and the associated public meeting, DOE intends to hold 

additional meetings with manufacturers as part of the consultative process for the manufacturer 

impact analysis conducted during the NOPR phase of the rulemaking. 

DOE developed spreadsheets for the engineering, LCC, PBP, and national impact 

analyses (NIA) for each product class, as well as spreadsheets for the market assessment, product 

price determination, and energy use and end-use load characterization. The LCC workbook 

calculates the LCC and PBP at various energy efficiency levels. The NIA workbook does the 

same for national energy savings (NES) and national net present values (NPVs). All of these 

spreadsheets are available on the DOE website for battery chargers and external power supplies: 

http://www.eere.energy.gov/buildings/appliance_standards/residential/battery_external_std_2008

EERE-2008-BT-STD-0005 COMMENT 31
1-6

.html. DOE can also provide various quantitative outputs from its analyses in machine-readable 

format upon request. For example, trial runs from the LCC Monte Carlo simulations could be 

provided in such a format. 

1.4 STRUCTURE OF THE DOCUMENT 

The preliminary TSD describes the analytical approaches used in the preliminary analysis 

and presents preliminary results. The TSD consists of 14 chapters, an executive summary, two 

reports, and several appendices. 

Executive Summary: Describes the rulemaking process, identifies the key 

results of the preliminary analyses, and identifies the key issues for which 

DOE seeks public comment that resulted from the preliminary analyses. 

Chapter 1 Introduction: provides an overview of the appliance standards program 

and how it applies to the battery charger and external power supply 

rulemaking, and outlines the structure of the document. 

Chapter 2 Analytical Framework: describes the methodology, the analytical tools, 

and relationships among the various analyses, summarizes comments 

DOE received on the framework document, and explains DOE’s responses 

to those comments. 

Chapter 3 Market and Technology Assessment: characterizes the market for the 

considered products and the technologies available for increasing energy 

efficiency. 

Chapter 4 Screening Analysis: identifies all the design options that improve 

efficiency of the considered products, and determines which technology 

options are viable for consideration in the engineering analysis. 

Chapter 5 Engineering Analysis: discusses the methods used for developing the 

relationship between increased manufacturer price and increased 

efficiency. 

Chapter 6 Product Price Determination: discusses the methods used for establishing 

markups for converting manufacturer prices to final product prices. 

Chapter 7 Energy Use Analysis: discusses the process used for generating energyuse estimates for the considered products as a function of standard levels. 

Chapter 8 Life-Cycle Cost and Payback Period Analyses: discusses the effects of 

standards on individual customers and users of the products and compares 

the LCC and PBP of products with and without higher energy 

conservation standards. 

EERE-2008-BT-STD-0005 COMMENT 31
1-7

Chapter 9 Shipments Analysis: discusses the methods used for forecasting the total 

number of products that would be affected by standards. 

Chapter 10 National Impact Analysis: discusses the methods used for forecasting 

national energy consumption and national consumer economic impacts in 

the absence and presence of standards. 

Chapter 11 Life-Cycle Cost Subgroup Analysis: discusses the effects of standards on 

different subgroups of consumers and compares the LCC and PBP of 

products with and without higher energy conservation standards for these 

consumers. 

Chapter 12 Preliminary Manufacturer Impact Analysis: discusses the effects of 

standards on the finances and profitability of product manufacturers. 

Chapter 13 Utility Impact Analysis: discusses the effects of standards on electric and 

gas utilities. 

Chapter 14 Employment Impact Analysis: discusses the effects of standards on 

national employment. 

Report Environmental Assessment for Battery Chargers and External Power 

Supplies: discusses the effects of standards on three pollutants – sulfur 

dioxide (SO2), nitrogen oxides (NOX), and mercury – as well as carbon 

emissions. 

Report Regulatory Impact Analysis for Battery Chargers and External Power 

Supplies: discusses the impact of non-regulatory alternatives to efficiency 

standards. 

Appendices: 

3A Battery Charger and External Power Supply Applications 

3B Battery Charger and External Power Supply Efficiency Programs 

3C Evaluation Methods for Differentiating Wall Adapters with Charge 

Control 

5A External Power Supply Test Data 

5B Battery Charger Test Data 

5C Manufacturer Interview Guides 

EERE-2008-BT-STD-0005 COMMENT 31
1-8

7A Battery Charger and External Power Supply Usage Profiles, Application 

States, and Loading Points 

7B Battery Charger and External Power Supply Application-Level Unit 

Energy Consumption Values 

8A User Instructions for LCC and PBP Spreadsheets

8B Supplementary LCC and PBP Results 

8C End-Use Application Inputs for the LCC 

8D Residential Discount Rate Distributions 

10A Net Present Value under Alternative Electricity Price Scenarios 

12A MIA Manufacturer Interview Guide 

15A Interagency Report on the Social Cost of Carbon 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

CHAPTER 2. ANALYTICAL FRAMEWORK, COMMENTS FROM
 

INTERESTED PARTIES, AND DOE RESPONSES
 

TABLE OF CONTENTS 

CHAPTER 2. ANALYTICAL FRAMEWORK, COMMENTS FROM INTERESTED
 

PARTIES, AND DOE RESPONSES .............................................................................. 2-1
 

2.1 Introduction.......................................................................................................... 2-1
 

2.1.1 Overview of Analyses.............................................................................. 2-1
 

2.1.2 Test Procedures........................................................................................ 2-3
 

2.2 Scope of Coverage ............................................................................................... 2-5
 

2.2.1 What Is an External Power Supply? ........................................................ 2-5
 

2.2.2 What Is a Battery Charger?...................................................................... 2-9
 

2.2.3 What Is a Consumer Product?................................................................ 2-10
 

2.3 Market and Technology Assessment ................................................................. 2-12
 

2.3.1 Market Assessment ................................................................................ 2-12
 

2.3.2 Product Classes ...................................................................................... 2-14
 

2.3.3 Technology Assessment......................................................................... 2-29
 

2.4 Screening Analysis............................................................................................. 2-34
 

2.4.1 Technology Options Screened Out ........................................................ 2-35
 

2.5 Engineering Analysis ......................................................................................... 2-36
 

2.5.1 Approaches to Conducting the Engineering Analysis ........................... 2-36
 

2.5.2 Engineering Analysis for Class A External Power Supplies ................. 2-37
 

2.5.3 Engineering Analysis for Non-Class A EPSs ........................................ 2-48
 

2.5.4 Engineering Analysis for Battery Chargers ........................................... 2-55
 

2.6 Markups to Determine Product Price................................................................. 2-63
 

2.7 Energy Use Analysis.......................................................................................... 2-63
 

2.7.1 External Power Supply Usage and Energy Consumption...................... 2-64
 

2.7.2 Battery Charger Usage and Energy Consumption ................................. 2-65
 

2.8 Life-Cycle Cost and Payback Period Analysis .................................................. 2-65
 

2.8.1 Approach................................................................................................ 2-66
 

2.8.2 Life-Cycle Cost Inputs........................................................................... 2-67
 

2.8.3 Payback Period....................................................................................... 2-72
 

2.8.4 Sensitivity Analysis ............................................................................... 2-73
 

2.9 Shipments Analysis............................................................................................ 2-73
 

2.9.1 Shipments Forecast ................................................................................ 2-74
 

2.9.2 Efficiency Forecast ................................................................................ 2-74
 

2.10 National Impact Analysis................................................................................... 2-76
 

2.10.1 Approach................................................................................................ 2-76
 

2.10.2 NIA Inputs ............................................................................................. 2-77
 

2.10.3 National Energy Savings Analysis......................................................... 2-77
 

2.10.4 Net Present Value Analysis ................................................................... 2-78
 

2.11 Life-Cycle Cost Subgroup Analysis .................................................................. 2-78
 

2.12 Preliminary Manufacturer Impact Analysis....................................................... 2-79
 

2.12.1 Sources of Information for the MIA ...................................................... 2-79
 

2.12.2 Industry Cash-Flow Analysis................................................................. 2-80
 

2-i 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

2.12.3 Manufacturer Subgroup Analysis .......................................................... 2-80
 

2.12.4 Competitive Impacts Assessment .......................................................... 2-81
 

2.12.5 Cumulative Regulatory Burden ............................................................. 2-81
 

2.12.6 Preliminary Results for the Manufacturer Impact Analysis .................. 2-81
 

2.12.7 Impacts on Shipments............................................................................ 2-81
 

2.12.8 Timing.................................................................................................... 2-81
 

2.12.9 Efficiency Levels ................................................................................... 2-82
 

2.12.10 Regulatory Approval........................................................................... 2-82
 

2.12.11 Conversion Costs ................................................................................ 2-82
 

2.12.12 Efficiency as a Selling Point............................................................... 2-82
 

2.12.13 Profit Margins ..................................................................................... 2-82
 

2.13 Utility Impact Analysis ...................................................................................... 2-82
 

2.14 Employment Impact Analysis............................................................................ 2-83
 

2.15 Environmental Assessment................................................................................ 2-83
 

2.15.1 Carbon Dioxide...................................................................................... 2-83
 

2.15.2 Sulfur Dioxide........................................................................................ 2-84
 

2.15.3 Nitrogen Oxides..................................................................................... 2-84
 

2.15.4 Mercury.................................................................................................. 2-84
 

2.15.5 Particulate Matter................................................................................... 2-85
 

2.15.6 Monetization of Emissions Reduction Benefits..................................... 2-85
 

2.16 Regulatory Impact Analysis............................................................................... 2-86
 

2.17 Additional Comments from Interested Parties................................................... 2-87
 

2.17.1 Temporary Exemptions from Standards for Replacement Parts............ 2-87
 

2.17.2 Labeling Requirements and Marking Protocol ...................................... 2-87
 

2.17.3 Standards Compliance and Enforcement ............................................... 2-88
 

2.17.4 Publishing Public Comments on the Internet......................................... 2-88
 

2.17.5 Public Meeting Webcast ........................................................................ 2-88
 

LIST OF TABLES 

TABLE 2.1 CLASS-SETTING CHARACTERISTICS CONSIDERED ................................. 2-15
 

TABLE 2.2 CLASS A EPS PRODUCT CLASSES.................................................................. 2-27
 

TABLE 2.3 MULTIPLE VOLTAGE EPS PRODUCT CLASSES .......................................... 2-27
 

TABLE 2.4 HIGH POWER EPS PRODUCT CLASSES......................................................... 2-27
 

TABLE 2.5 MEDICAL EPS PRODUCT CLASSES................................................................ 2-27
 

TABLE 2.6 MADB EPS PRODUCT CLASSES...................................................................... 2-27
 

TABLE 2.7 BC PRODUCT CLASSES USED IN THE PRELIMINARY ANALYSIS. ......... 2-29
 

TABLE 2.8 CLASS A EPS REPRESENTATIVE PRODUCT CLASS AND SCALED 

PRODUCT CLASSES................................................................................................... 2-37
 

TABLE 2.9 CLASS A EPS REPRESENTATIVE UNITS ....................................................... 2-38
 

TABLE 2.10 SUMMARY OF CLASS A EPS CANDIDATE STANDARD LEVELS OF
 

EFFICIENCY ................................................................................................................ 2-38
 

TABLE 2.11 BASELINE (CSL 0) EISA 2007 ACTIVE-MODE EFFICIENCY FOR PRODUCT 

CLASS A1 ..................................................................................................................... 2-39
 

2-ii 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

TABLE 2.12 EISA 2007 STANDARD EQUATION FOR MAXIMUM NO-LOAD MODE 

POWER CONSUMPTION............................................................................................ 2-39
 

TABLE 2.13 ENERGY STAR 2.0 EQUATION FOR MINIMUM ACTIVE-MODE 

TABLE 2.14 ENERGY STAR 2.0 STANDARD EQUATION FOR NO-LOAD MODE POWER 

TABLE 2.15 CSL 2 INTERMEDIATE ACTIVE-MODE EFFICIENCY FOR PRODUCT 

TABLE 2.16 CSL 2 INTERMEDIATE NO-LOAD MODE POWER CONSUMPTION FOR 

TABLE 2.17 CSL 3 BEST IN MARKET ACTIVE-MODE EFFICIENCY FOR PRODUCT 

TABLE 2.18 CSL 3 BEST IN MARKET NO-LOAD MODE POWER CONSUMPTION FOR 

TABLE 2.19 CSL 4 MAX TECH ACTIVE-MODE EFFICIENCY FOR PRODUCT CLASS A1
 

TABLE 2.20 CSL 4 MAX TECH NO-LOAD MODE POWER CONSUMPTION FOR 

TABLE 2.21 ACTIVE-MODE EFFICIENCY CSLS FOR LOW-VOLTAGE EPSS (PRODUCT 

TABLE 2.22 NO-LOAD POWER CSLS FOR AC/AC EPSS (PRODUCT CLASSES A3 AND 

TABLE 2.31 MULTIPLE-VOLTAGE EPS CANDIDATE STANDARD LEVELS OF
 

TABLE 2.32 HIGH-POWER EPS CANDIDATE STANDARD LEVELS OF EFFICIENCY2-51
 

TABLE 2.36 THE BC REPRESENTATIVE UNITS FOR EACH REPRESENTATIVE 

TABLE 2.37 CANDIDATE STANDARD LEVELS FOR THE BC REPRESENTATIVE UNITS
 

TABLE 2.38 THE BC REPRESENTATIVE UNITS FOR EACH REPRESENTATIVE AND 

TABLE 2.39 CANDIDATE STANDARD LEVELS FOR THE SCALED BC
 

EFFICIENCY FOR BASIC OUTPUT VOLTAGE EPSS ............................................ 2-39
 

CONSUMPTION........................................................................................................... 2-40
 

CLASS A1 ..................................................................................................................... 2-40
 

PRODUCT CLASS A1.................................................................................................. 2-40
 

CLASS A1 ..................................................................................................................... 2-41
 

PRODUCT CLASS A1.................................................................................................. 2-41
 

........................................................................................................................................ 2-42
 

PRODUCT CLASS A1.................................................................................................. 2-42
 

CLASSES A2 AND A4)................................................................................................ 2-47
 

A4) ................................................................................................................................. 2-47
 

TABLE 2.23 MULTIPLE VOLTAGE EPS REPRESENTATIVE PRODUCT CLASSES..... 2-48
 

TABLE 2.24 MULTIPLE-VOLTAGE EPS REPRESENTATIVE UNITS.............................. 2-48
 

TABLE 2.25 HIGH POWER EPS REPRESENTATIVE PRODUCT CLASSES ................... 2-49
 

TABLE 2.26 HIGH-POWER EPS REPRESENTATIVE UNITS ............................................ 2-49
 

TABLE 2.27 PROPOSED MEDICAL EPS REPRESENTATIVE PRODUCT CLASSES..... 2-49
 

TABLE 2.28 POSSIBLE MEDICAL EPS REPRESENTATIVE UNITS................................ 2-49
 

TABLE 2.29 PROPOSED MADB EPS REPRESENTATIVE PRODUCT CLASSES ........... 2-50
 

TABLE 2.30 POSSIBLE MADB EPS REPRESENTATIVE UNITS ...................................... 2-50
 

EFFICIENCY ................................................................................................................ 2-51
 

TABLE 2.33 MEDICAL EPS CANDIDATE STANDARD LEVELS OF EFFICIENCY ...... 2-52
 

TABLE 2.34 MADB EPS CANDIDATE STANDARD LEVELS OF EFFICIENCY............. 2-53
 

TABLE 2.35 BC REPRESENTATIVE PRODUCT CLASSES ............................................... 2-56
 

PRODUCT CLASS ....................................................................................................... 2-57
 

........................................................................................................................................ 2-59
 

SCALED PRODUCT CLASS....................................................................................... 2-62
 

REPRESENTATIVE UNITS. ....................................................................................... 2-62
 

TABLE 2.40 SUMMARY OF INPUTS USED IN THE LIFE-CYCLE COST ANALYSIS .. 2-67
 

TABLE 2.41 MARKET-WEIGHTED LIFETIMES FOR REPRESENTATIVE UNITS........ 2-70
 

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TABLE 2.42 INPUT VARIATIONS FOR THE SENSITIVITY ANALYSIS......................... 2-73
 

TABLE 2.43 SUMMARY OF INPUTS USED IN THE NATIONAL IMPACT ANALYSIS.......
 

.................................................................................................................................................... 2-77
 

LIST OF FIGURES 

FIGURE 2.1 FULL COST OF PRODUCT: BREAKDOWN OF PRODUCTION AND NONPRODUCTION COSTS ................................................................................................ 2-43
 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

CHAPTER 2. ANALYTICAL FRAMEWORK, COMMENTS FROM
 

INTERESTED PARTIES, AND DOE RESPONSES
 

2.1 INTRODUCTION
 

The Energy Policy and Conservation Act of 1975, as amended (EPCA) requires the U.S. 

Department of Energy (DOE) to promulgate energy conservation standards for consumer 

products that achieve the maximum improvement in energy efficiency that the Department 

determines is both technologically feasible and economically justified. 42 U.S.C. § 

6295(o)(2)(A). This chapter provides a description of the general analytical framework that DOE 

is using to develop such standards for battery chargers (BCs) and external power supplies 

(EPSs). The analytical framework is a description of the methodology, the analytical tools, and 

relationships among the various analyses that are part of this rulemaking. 

DOE developed this analytical framework and documented its findings in the Energy 

Conservation Standards Rulemaking Framework Document for BCs and Class A EPSs (June 4, 

2009). DOE announced the availability of the framework document in a Notice of Public 

Meeting and Availability of a Framework Document published in the Federal Register on June 4, 

2009. 74 FR 26816. DOE presented the analytical approach to interested parties during a public 

meeting held on July 16, 2009. In addition to describing the analytical framework, this chapter 

summarizes written and oral comments DOE received from interested parties on the framework 

document and explains DOE’s responses to those comments. The framework document is 

available at 

www1.eere.energy.gov/buildings/appliance_standards/residential/battery_external_std_2008.htm 

l 

DOE published a Notice of Proposed Determination (NOPD) for non-Class A EPSs on 

November 3, 2009, followed by a final determination for non-Class A EPSs that was published 

on May 14, 2010. This final determination, which was issued as a rule consistent with the 

particular requirements set out in EPCA, indicated that energy conservation standards for nonClass A EPSs appear to be technologically feasible and economically justified, and are likely to 

result in significant energy savings. 74 FR 56928 and 75 FR 27170, respectively. Consequently, 

the Department is including non-Class A EPSs in the energy conservation standards for BCs and 

EPSs. In its determination, DOE also indicated that it would address certain comments raised by 

interested parties in the forthcoming preliminary analysis since they raised general issues related 

to BCEPS. 

Significant changes in analytical approach from what was described in the framework 

document and determination analysis are also noted in this chapter. Lastly, note that the 

executive summary of the preliminary TSD contains a list of issues for which DOE seeks public 

comment. Those issues are explained in detail in the relevant sections below. 

2.1.1 Overview of Analyses 

The analyses performed as part of this rulemaking stage and reported in this preliminary 

technical support document (preliminary TSD) are listed below. 

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A market and technology assessment to characterize the relevant product markets and 

existing technology options, including prototype designs. 

A screening analysis to review each technology option and determine if it: is 

technologically feasible; is practical to manufacture, install, and service; would adversely 

affect product utility or product availability; or would have adverse impacts on health and 

safety. 

An engineering analysis to develop cost-efficiency relationships that show the 

manufacturer’s cost of achieving increased efficiency. DOE determines the increased cost 

to the consumer through an analysis of engineering markups, which convert manufacturer 

production cost (MPC) for EPSs and efficiency-related manufacturing cost (ERMC) for 

BCs to manufacturer selling price (MSP). DOE uses different price structures for EPSs 

and BCs because EPSs are contained within a single enclosure that has a single MSP 

whereas BCs often share an enclosure with other non-BC related components. Thus, 

DOE uses ERMC to address the prices of components pertinent to BCs only. 

A markup analysis to develop distribution channel markups that relate the MSP to the 

cost to the consumer. 

An energy use analysis to determine the annual energy use in the field of the considered 

products. 

Life-cycle cost (LCC) and payback period (PBP) analyses to calculate, at the consumer 

level, the discounted savings in operating costs throughout the estimated average life of 

the covered products, compared to any increase in the installed cost for the products 

likely to result directly from imposition of the standard. A sensitivity analysis to 

determine LCC results in a high-savings case and a low-savings case. 

A shipments analysis to forecast product shipments, which are then used to calculate the 

national impacts of standards on energy, net present value (NPV), and future 

manufacturer cash flows. 

A national impact analysis (NIA) to assess the aggregate impacts at the national level of 

the NPV of total consumer LCC and national energy savings (NES). 

A preliminary manufacturer impact analysis to assess the potential impacts of energy 

conservation standards on manufacturers, such as impacts on capital conversion 

expenditures, marketing costs, shipments, and research and development costs. 

The analyses DOE will perform in the subsequent Notice of Proposed Rulemaking 

(NOPR) stage include those listed below. In addition, DOE will revise the analyses it performed 

in the preliminary stage based on comments and new information received. 

An LCC subgroup analysis to evaluate variations in customer characteristics that might 

cause a standard to affect particular consumer sub-populations, such as low-income 

households, differently than the overall population. 

A manufacturer impact analysis to estimate the financial impact of standards on 

manufacturers and to calculate impacts on competition, employment, and manufacturing 

capacity. 

A utility impact analysis to estimate the effects of proposed standards on electric, gas, or 

oil utilities. 

An employment impact analysis to assess the aggregate impacts on national employment. 

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An environmental impact analysis to provide estimates of the effects of amended energy 

conservation standards on three pollutants—sulfur dioxide (SO2), nitrogen oxides (NOX), 

and mercury (Hg)—as well as carbon emissions. 

A regulatory impact analysis to present major alternatives to proposed amended energy 

conservation standards that could achieve substantially the same regulatory goal at a 

lower cost. 

Note that non-Class A EPSs (discussed in section 2.2.1.1) are included in the preliminary 

market and technology assessment, markup analysis, and shipments analysis, but are not 

included in the preliminary engineering analysis or in those analyses that make use of 

engineering outputs, i.e., the LCC and NIA. DOE intends to conduct a comprehensive analysis of 

potential standards for these products in the NOPR stage of the rulemaking. 

2.1.2 Test Procedures 

Section 323 of EPCA (42 U.S.C. § 6293) sets forth generally applicable criteria and 

procedures for DOE’s adoption and amendment of test procedures, which manufacturers of 

covered products must use to certify to the DOE that their products comply with EPCA energy 

conservation standards and to quantify the efficiency of their products. Also, these test 

procedures must be used whenever testing is required in an enforcement action to determine 

whether covered products comply with EPCA standards. 

DOE has adopted test procedures for both BCs and EPSs. These are described in the 

sections below. Further discussion of testing and efficiency metrics and their application to the 

analysis of achievable performance can be found in sections 2.3.3.1 for EPSs and 2.3.3.3 for 

BCs. 

2.1.2.1 EPS Test Procedures 

On December 8, 2006, DOE codified a test procedure final rule for EPSs in appendix Z to 

subpart B of 10 CFR Part 430 (―Uniform Test Method for Measuring the Energy Consumption 

of External Power Supplies‖). 71 FR 71340, 71368. DOE’s test procedure, based on the 

ENERGY STAR EPS test procedure, measures active-mode efficiency and no-load mode 

(standby mode) power consumption. In the standby and off mode test procedure NOPR for BCs 

and EPSs, 73 FR 48054, 48063 (August 15, 2008), DOE proposed to amend the EPS test 

procedure to add a measurement of power consumption in off mode, where, if the EPS has an 

on-off switch, the EPS is connected only to mains and the switch is turned off. The NOPR also 

included a proposed test procedure for multiple-voltage EPSs. The amendments for standby and 

off mode were included in the final rule, published March 27, 2009. 74 FR 13318, 13335. In the 

final rule DOE also reserved a section of the test procedure for multiple-voltage EPSs. DOE is 

considering amending the EPS test procedure as part of its revision to the BC test procedure 

NOPR published on April 2, 2010. 75 FR 16958. 

Active mode conversion efficiency is the ratio of output power to input power. DOE 

averages the efficiency at four loading conditions—25, 50, 75, and 100 percent of maximum 

rated output current—to assess the performance of a single-voltage EPS. For multiple-voltage 

EPSs, the test procedure NOPR proposed that the test procedure yield the efficiency 

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measurement at the same four loading conditions without averaging them. 75 FR 16958, 16974. 

For single-voltage EPSs, DOE measures the power consumption of the EPS when disconnected 

from the consumer product, which is termed no-load power consumption. If the EPS has an onoff switch, the switch is on when conducting the measurement. DOE proposed to treat no-load 

and off modes similarly for multiple-voltage EPSs in the NOPR. 

2.1.2.2 BC Test Procedures 

On December 8, 2006, DOE adopted a test method to measure the efficiency of battery 

chargers. 71 FR 71340, 71368. This test method, based on the U.S. Environmental Protection 

Agency’s (EPA) ENERGY STAR ―Test Methodology for Determining the Energy Performance 

of Battery Charging Systems,‖ measures the power consumed by BCs in maintenance and nobattery, as well as the energy recovered from the battery during discharge, by calculating an 

energy ratio. 

In the December 8, 2006, Test Procedure Final Rule, DOE stated that it intended to study 

further BC active mode energy consumption and reserved a section in the test procedure (section 

4(b) of appendix Y to subpart B of 10 CFR Part 430). 71 FR 71340, 71360. During the 

framework document public meeting, DOE presented several potential approaches to measuring 

battery charger energy consumption in active mode. Numerous interested parties submitted 

comments on active mode measurement in general but noted several specific issues: 

Harmonization of DOE’s BC active mode test procedure with the BC test procedure 

adopted by the California Energy Commission (CEC) 

Limiting testing to U.S. line-voltage AC input (115 volts at 60 hertz) 

Shortening the charge and maintenance mode testing period to less than 24 hours 

Incorporating usage profiles into the test procedure 

Measuring charger output energy instead of battery output energy 

Measurements at alternative depths-of-discharge to better reflect consumer use 

Test procedure rulemaking schedule 

Appropriate voltage for testing multiple-voltage BCs 

Power factor measurement 

DOE took the comments on the above topics under advisement as it developed 

amendments to its existing BC test procedure to accommodate energy consumption in active 

mode. Comments relevant to the proposal, as well as the proposed amendments themselves, are 

discussed in depth in the BC active mode test procedure NOPR, published on April 2, 2010. 75 

FR 16958, 16963-76. 

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If adopted, these proposed amendments to the BC test procedure would discontinue use 

of the non-active energy ratio in favor of metrics related to energy consumption in each of the 

energy-consuming modes of operation of a BC. As described above, these include active, 

maintenance, standby, and off modes; thus, the test procedure would return four separate values. 

How these four mode-specific metrics would be combined for the purpose of an energy 

conservation standard is discussed further in section 2.3.3.3. 

2.2 SCOPE OF COVERAGE 

This standards rulemaking concerns all BCs and EPSs, which are defined as follows: 

The term battery charger means a device that charges batteries for consumer 

products, including battery chargers embedded in other consumer products. (42 

U.S.C. 6291(32)) 

The term external power supply means an external power supply circuit that is used 

to convert household electric current into DC current or lower-voltage AC current to 

operate a consumer product. (42 U.S.C. 6291(36)(A)) 

DOE has received numerous comments on scope in connection with this rulemaking and 

the related test procedure and determination rulemakings. For example, Vivitar requested clear 

interpretations of statutory definitions to ease uncertainty among manufacturers. (Vivatar, Pub. 

Mtg. Tr., No. 14 at pp. 115, 375) PG&E commented that there is a tradeoff between simplicity 

and maximum energy savings. (PG&E, Pub. Mtg. Tr., No. 14 at p. 118) AHAM similarly 

commented on the impossibility of covering every possible EPS or BC product and encouraged 

DOE to maintain simplicity when deciding issues of scope. (AHAM, Pub. Mtg. Tr., No. 14 at 

p. 95) 

Ambiguities inherent in the statutory definitions have left interested parties with 

questions about which products are EPSs and which are BCs. The following subsections are 

intended to answer these questions. 

2.2.1 What Is an External Power Supply? 

As noted above, an EPS is ―an external power supply circuit that is used to convert 

household electric current into DC current or lower-voltage AC current to operate a consumer 

product.‖ Thus, DOE understands an EPS to have four key attributes: 

1. An EPS is outside (external to) the product it operates, 

2. An EPS attaches to and obtains power from mains (household electric power), 

3.	 An EPS performs power conversion but does not contain additional charge control 

functions, and 

4. An EPS powers a consumer product (discussed in section 2.2.3 below). 

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Of these four attributes, the third has generated the most discussion because of the 

difficulty of clearly establishing the presence of charge control. DOE recognizes that some wall 

adaptersa do more than simply ―convert household electric current into DC current or lowervoltage AC current.‖ They also perform charge control functionsb as part of a battery charging 

system. As proposed in the framework document, DOE has decided to exclude these wall 

adapters from the universe of EPSs with the understanding that their energy performance will be 

addressed by BC standards. 

2.2.1.1 Class A Versus Non-Class A EPSs 

EPCA provides definitions for EPS and Class A EPS. Non-Class A EPSs, then, are those 

devices that fit the definition of an EPS but do not fit the definition of a Class A EPS. 

In general, a Class A EPS is a device that: 

1.	 is designed to convert line voltage AC input into lower voltage AC or DC output; 

2.	 is able to convert to only one AC or DC output voltage at a time; 

3.	 is sold with, or intended to be used with, a separate end-use product that 

constitutes the primary load; 

4.	 is contained in a separate physical enclosure from the end-use product; 

5.	 is connected to the end-use product via a removable or hard-wired male/female 

electrical connection, cable, cord, or other wiring; and 

6.	 has nameplate output power that is less than or equal to 250 watts. 

However, the term Class A EPS does not include any device that: 

I.	 requires Federal Food and Drug Administration listing and approval as a medical 

device in accordance with section 513 of the Federal Food, Drug, and Cosmetic 

Act (21 U.S.C. 360c); or 

II.	 powers the charger of a detachable battery pack or charges the battery of a 

product that is fully or primarily motor operated. (42 U.S.C. § 6291(36)(C)) 

Using this framework, DOE has identified four types of non-Class A EPSs: 

1.	 Multiple-Voltage EPSs: These devices are able to convert to more than one AC or DC 

output voltage at a time. 

2.	 High-Power EPSs: These devices have a nameplate output power greater than 250 

watts. 

3.	 Medical EPSs: These devices are used to power medical devices regulated by the 

Food and Drug Administration. 

4.	 MADB EPSs: These devices provide power to the battery chargers of motorized 

applications and detachable battery (MADB) packs. 

a The term ―wall adapter‖ refers to the device between mains and an application, that may or may not fit the 

statutory definition of ―external power supply‖ in that it may, in some cases, provide charge control in addition to 

power conversion. 

b Charge control functions include current and temperature sensing, timing, and current limiting, all of which are 

included in battery charging systems for safety reasons. 

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Medical EPSs include EPSs that power medical devices and EPSs that are themselves 

medical devices. A literal reading of EPCA would exclude from Class A only those EPSs that 

are themselves medical devices. The term ‖class A external power supply‖ excludes any device 

that requires Federal Food and Drug Administration listing and approval as a medical device in 

accordance with section 513 of the Federal Food, Drug, and Cosmetic Act (21 U.S.C. 360c).‖ 42 

U.S.C. 6291(36)(C)(ii)(I) However, a search of FDA’s product classification database for 

―power supply‖ reveals only one EPS that is a medical device—auxiliary power supply 

(alternating current (AC) or direct current (DC)) for external transcutaneous cardiac pacemakers. 

Furthermore, all EPSs used with medical devices must meet the special requirements of UL 

60601 (Underwriters Laboratories standard for power supplies for medical devices). 

Accordingly, because the exclusion applies to ―any device‖ covered by the FDA's listing and 

approval requirements, DOE interprets EPCA to also exclude from Class A those EPSs that 

power medical devices. 

MADB EPSs provide power to the chargers of motorized applications and/or detachable 

battery packs. A detachable battery is one that is contained in a separate enclosure from the 

product and intended to be removed or disconnected from the product for recharging. See 42 

U.S.C. 6291(52). MADB EPSs are employed by certain household appliances such as handheld 

vacuums, personal care products such as shavers, and DIY power tools. MADB EPSs were 

referred to as ―EPSs for BCs‖ in the determination analysis of non-Class A EPSs. DOE now uses 

the term ―MADB‖ to highlight the two unique aspects that EPCA specifies: motorized 

applications (MA) and detachable batteries (DB). 

DOE received two comments on what should be considered a detachable battery. Vivitar 

commented that batteries that are either physically or electrically disconnected for recharging 

should be considered detachable. (Vivitar, Pub. Mtg. Tr., No. 14 at p. 80) PG&E commented that 

the term should include AA batteries for flashlights. (PG&E, Pub. Mtg. Tr., No. 14 at p. 88) 

Vivitar’s comment regarded camera batteries recharged inside the camera by a wall 

adapter. Because the battery is electrically disconnected from the functional part of the camera 

during charging, and a user cannot operate the camera while the battery is charging, the battery 

can be considered detachable. The wall adapter could therefore be considered a MADB nonClass A EPS, pending the results of other DOE tests seeking to determine the presence of charge 

control, described in section 2.2.1.3. 

The flashlight batteries PG&E referred to are not detachable for purposes of the present 

discussion. Universal rechargeable batteries (AA, AAA, etc.) that are removed from the product 

they power and inserted into a separate ―universal‖ BC for charging may be detachable, but are 

not battery packs. Thus, the EPS that powers such a universal BC is not excluded from Class A. 

2.2.1.2 Wall Adapters Without Charge Control 

Wall adapters without charge control are EPSs, even when they are part of a battery 

charging system. This is true of both Class A and non-Class A EPSs. This decision is consistent 

with Approach A, for which DOE received widespread support from interested parties. Under 

this approach, described in detail in the framework document, only wall adapters without charge 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

control would be subject to EPS standards. Methods for identifying the presence of charge 

control in wall adapters are discussed in section 2.2.1.3 and chapter 3 of the TSD. 

FRIWO, Motorola, and PG&E were generally unified in their support for Approach A. 

Commenters agreed that it is appropriate to subject wall adapters without charge control to EPS 

standards because they can be used for other applications besides battery charging. (FRIWO, No. 

21 at p. 1; PG&E, Pub. Mtg. Tr., No. 14 at p. 62; Motorola, No. 25 at p. 1; PG&E, No. 20 at p. 3) 

PG&E commented that a significant percentage of wall adapters used with battery chargers lack 

charge control and thus would be considered EPSs under Approach A, including those for 

cellular telephones, cordless telephones, notebook computers, portable media players, and other 

digital electronics. (PG&E, No. 20 at p. 3) PG&E added that due to EPS efficiency standards in 

California, which covered all wall adapters without regard for the presence of charge control, 

―nearly all wall adapters considered in the framework document should already be compliant to 

EISA 2007 levels (Roman number IV) at least in California, which is a significant portion of the 

U.S. economy.‖ (PG&E, No. 20 at p. 6) 

AHAM and Wahl Clipper asked DOE to consider an alternative approach for wall 

adapters that are used with motorized applications and/or detachable batteries. Specifically, these 

commenters requested that DOE not consider these devices EPSs at all, irrespective of the 

presence of charge control. (AHAM, No. 16 at p. 2-3; Wahl Clipper, No. 23 at p. 1) Under this 

approach there would be no MADB EPSs. PTI implied in a comment submitted in response to 

the NOPD that it would also support such an approach when it stated its preference for an 

approach that excludes from coverage under EPS standards any wall adapter that is incorporated 

as part of a BC. (PTI, EERE-2009-BT-DET-0005 No. 5 at pp. 1-2) As noted in the determination 

published on May 14, 2010, under the approach recommended by AHAM and Wahl Clipper, 

wall adapters that power the chargers of detachable battery packs or charge the batteries of 

products that are fully or primarily motor-operated would not be subject to EPS standards while 

those wall adapters (without charge control) that power other battery-charged applications would 

be subject to Class A EPS standards. 75 FR 27170. DOE is concerned that this would create two 

distinct definitions of an EPS that would prevent one from readily identifying a particular wall 

adapter as being an EPS until it is known whether it powers the charger of a detachable battery 

pack or charges the battery of a product that is fully or primarily motor operated. In the absence 

of information that would alleviate this concern, DOE continues to consider wall adapters 

without charge control to be EPSs, whether they are Class A or non-Class A. 

2.2.1.3 Identification of Charge Control in Wall Adapters 

In the framework document, DOE sought stakeholder comment on four possible criteria 

for identifying charge control in a wall adapter: short-circuit operation, voltage regulation, noload voltage, and no-battery operation. DOE received comments on these criteria and alternative 

methods for identifying charge control. 

Commenters challenged the criteria that DOE proposed to identify ―charge control‖ by 

claiming that the criteria presented by DOE are impractical. PG&E commented that the electrical 

tests proposed by DOE for identifying a wall adapter with charge control function are ineffective 

and recommended that DOE rely on physical characteristics to determine which wall adapters 

should be excluded from treatment as EPSs. PG&E noted that these physical characteristics 

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EERE-2008-BT-STD-0005 COMMENT 31
2-9

could include actual charge control circuitry or a state-of-charge indicator. (PG&E, No. 20 at 

pp. 3-4; PG&E, Pub. Mtg. Tr., No. 14 at p. 61) In response to the notice of proposed 

determination, PG&E also identified a chemistry-type selector switch as a physical characteristic 

the presence of which could be used to determine whether charge control is present in a wall 

adapter. (PG&E, EERE-2009-BT-DET-0005 No. 7 at p. 7) Similarly, FRIWO commented that 

DOE should consider the presence of LED charge indicator lights and temperature sensors. 

(FRIWO, No. 21 at p. 1) Finally, PG&E commented that it is possible to have no charge control 

at all in the battery charging system—neither in the wall adapter nor in subsequent enclosures. 

(PG&E, Pub. Mtg. Tr., No. 14 at p. 130) 

Although some battery charging systems may not have components explicitly devoted to 

charge control, all require this function, and DOE intends to define it. Specifically, DOE is 

considering adopting the EPA criteria for establishing the presence of charge control in a wall 

adapter. DOE would consider a wall adapter with charge control to have ―batteries or battery 

packs that physically attach directly‖ or a ―battery chemistry or type selector switch AND an 

indicator light or state of charge meter.‖ These criteria are modeled after those contained in the 

BC standards proposal developed by PG&E.1 Nonetheless, DOE is also evaluating other criteria 

that might be more appropriate to determine whether charge control is present in a wall adapter. 

Details of these other criteria can be found in chapter 3 of the preliminary TSD and appendix 3C.

2.2.2 What Is a Battery Charger? 

As noted above, a BC is ―a device that charges batteries for consumer products, including 

battery chargers embedded in other consumer products.‖ Like EPSs, BCs are used with 

consumer products. However, unlike EPSs, the statutory definition of BCs also includes products 

not powered from mains. Further, BCs may be wholly embedded in another consumer product, 

wholly separate from another consumer product, or partially inside and partially outside another 

consumer product. 

2.2.2.1 Battery Chargers with Wall Adapters 

When a wall adapter is present, it is considered part of the BC. This approach is 

consistent with the statutory definition of a BC and has received broad support from interested 

parties. Including the wall adapter in the BC is a key part of Approach A, which, as indicated 

above, received support from a number of stakeholders. Further, AHAM and PG&E commented 

that DOE should not separate components of a battery charging system when testing its 

efficiency. (AHAM, No. 16 at p. 1; PG&E, Pub. Mtg. Tr., No. 14 at p. 60) PG&E commented 

that the efficiency of a wall adapter is not indicative of the energy consumption of the entire 

battery charging system. (PG&E, No. 20 at p. 13) 

DOE received two comments requesting alternative approaches. Vivitar requested that 

DOE set separate standards for wall adapters for battery charging applications, rather than 

including them within the scope of either BC or EPS standards. Delta-Q commented that DOE's 

scope of analysis should be limited to power conversion functions (e.g., only the wall adapter) 

and should not include charge control. (Vivitar, Pub. Mtg. Tr., No. 14 at p. 112; Delta-Q, No. 15 

at p. 1) 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

 

 

 

After examining these alternative approaches proposed by interested parties, DOE 

determined that they would be inconsistent with the statutory framework set by Congress. 

Regarding Vivitar’s request, DOE is considering new and amended standards for BCs and EPSs. 

Regarding Delta-Q’s request, DOE cannot limit the scope of its BC analysis only to power 

conversion functions because a BC’s power-consuming functions extend beyond power 

conversion to include charge control. Often, charge control is included not in the wall adapter, 

but in the end-use consumer products, and the statute clearly specifies that DOE is to include 

within its scope BCs ―embedded in other consumer products.‖ 

2.2.2.2 DC-Powered Battery Charging Systems 

While many BCs are powered from AC mains, others have DC inputs, including those 

that obtain power from a computer’s universal serial bus (USB) port and those that connect to an 

automobile’s cigarette lighter receptacle. 

DOE received several comments from interested parties regarding DC-powered BCs. 

FRIWO asked that DC-powered battery chargers be included within the scope of the BC 

rulemaking (FRIWO, No. 21 at p. 1), whereas AHAM disagreed, asking that DOE exclude 

cigarette-lighter and USB adapters. (AHAM, No. 16 at p. 5) PG&E. commented that wall 

adapters sold as an after-market accessory for a USB BC should be considered part of a BC 

when sold by the same manufacturer. (PG&E, No. 20 at p. 3) Motorola commented that mobile 

phones are often charged from DC sources such as computers. (Motorola, Pub. Mtg. Tr., No. 14 

at p. 99) 

DOE is including all DC-powered BCs within the scope of this rulemaking. The BC 

definition, unlike the EPS definition, does not specify that the input power to the device must be 

AC. Many battery-charged consumer electronics can obtain power from a USB port, which 

provides power at 5 V DC (nominal). USB power sources include notebook and desktop 

computers, USB hubs, standalone USB wall adapters, and even the chairs in some airport 

lounges. Because USB power sources are becoming more varied and widespread, DOE is 

focusing its BC analysis on that which is between the USB port and the battery, without regard 

for the USB port’s power source. Standalone wall adapters with USB outputs are EPSs and, as 

such, are addressed as part of the EPS standards analysis. 

2.2.3 What Is a Consumer Product? 

An EPS operates a consumer product, and a BC charges batteries for consumer products. 

What, then, is a consumer product? The statutory definition of a consumer product is any article 

other than an automobile, as defined in section 32901(a)(3) of title 49, that consumes energy or 

water and which, to any significant extent, is distributed in commerce for personal use or 

consumption by individuals. (42 U.S.C. 6291(1)) 

The definition of automobile cited above states that except as provided in 49 U.S.C. § 

32908, the term ―automobile‖ means a 4-wheeled vehicle that is propelled by fuel, or by 

alternative fuel, manufactured primarily for use on public streets, roads, and highways and rated 

at less than 10,000 pounds gross vehicle weight, except (A) a vehicle operated only on a rail line; 

(B) a vehicle manufactured in different stages by 2 or more manufacturers, if no intermediate or 

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final-stage manufacturer of that vehicle manufactures more than 10,000 multi-stage vehicles per 

year; or (C) a work truck.‖ (49 U.S.C. 32901(a)(3)) The term ―alternative fuel‖ includes 

electricity. (49 U.S.C. 32901(a)(1)(J)) Given this definition, DOE will not examine BCs for 

electric automobiles, nor will it examine those for ―low-speed vehicles‖, which are similar to 

golf cars but are manufactured with additional safety features for on-road use. These vehicles are 

covered as automobiles under Federal Motor Vehicle Standard No. 500: Low-Speed Vehicles. 49 

CFR 571.500. 

DOE received a number of comments from interested parties related to the definition of 

consumer product and the scope of BC and EPS analyses and standards. Delta-Q asked whether 

high-power battery chargers would be covered by BC standards, (Delta-Q, No. 15 at p. 1) while 

Wahl requested that DOE exempt BCs with output power greater than 250 watts until an 

appropriate test procedure is developed. Wahl further requested that DOE exclude medical 

device BCs. (Wahl, No. 23 at p. 1) Motorola asked whether industrial products such as 

emergency/first-responder radios would be covered by standards, (Motorola, Pub. Mtg. Tr., No. 

14 at p. 349) and Schumacher requested that DOE include within its scope BCs used for 

automotive and other conveyance applications. (Schumacher, No. 27 at p. 2) 

High-power BCs and BCs for medical devices are indeed within the scope of this 

standards rulemaking, provided that the BCs charge batteries for consumer products as defined 

above. The BCs used to charge golf car batteries, for example, are covered products because golf 

cars are distributed in commerce for personal use or consumption by individuals and are not 

automobiles, as defined above; that is, they are not manufactured primarily for use on public 

streets, roads, and highways. DOE recognizes that many golf cars are in fact sold to businesses 

for use in golf course fleets. However, those sold to businesses are indistinguishable from those 

sold to individuals and, thus, all of the associated BCs are included within DOE’s scope. BCs for 

emergency/first-responder radios, in contrast, are not covered products because emergency/firstresponder radios and other products intended only for commercial, industrial, and institutional 

use are not consumer products. 

ASAP and PG&E recommended that DOE incorporate a wide variety of BCs in its 

standards analysis. (ASAP, Pub. Mtg. Tr., No. 14 at p. 39; PG&E, Pub. Mtg. Tr., No. 14 at p. 

49, 57) PG&E further recommended that DOE include in its analysis a variety of end-use 

applications, charger designs, and battery energy capacities and all common battery chemistries. 

PG&E provided a list of at least 30 consumer charger types in 14 different product categories for 

DOE to consider. (PG&E, Pub. Mtg. Tr., No. 14 at p. 57; PG&E, No. 20 at p. 8) Finally, 

Motorola commented that there are currently no provisions for testing the efficiency of ―systems 

with backup batteries for data retention‖ and indicated it feels a ―wide range of products‖ should 

be evaluated (Motorola, No. 25 at p. 2) AHAM warned DOE not to stray from the consumer 

products definition in NAECA. (AHAM, Pub. Mtg. Tr., No. 14 at p. 352) 

In its preliminary analysis, DOE characterized a variety of BCs and EPSs for a wide 

range of consumer products, including many that it had not examined previously. DOE expanded 

the scope of its analysis to cover over 50 applications for BCs and over 70 for EPSs. DOE tested 

and examined many charger designs ranging from inductively-coupled chargers to golf car 

chargers. DOE also examined the most common battery chemistries including lithium ion, nickel 

metal hydride, and sealed lead acid. DOE characterized BCs for batteries with energy capacities 

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ranging from 0.5 watt-hours to over 3 kilowatt-hours. While DOE analyzed uninterruptible 

power supplies that provide emergency backup power, it did not examine ―systems with backup 

batteries for data retention‖ such as those embedded in desktop computers. 

2.3 MARKET AND TECHNOLOGY ASSESSMENT 

2.3.1 Market Assessment 

DOE developed a qualitative and quantitative characterization of BC and EPS markets 

and industry structure. DOE based this market assessment, presented in full detail in chapter 3, 

on publicly available information, including purchased market research reports, as well as data 

and information submitted by interested parties. Where specific data was not available, DOE 

developed estimates based on industry studies, and data from similar products or associated 

applications. Issues addressed include market characteristics and trends, existing regulatory and 

non-regulatory efficiency improvement initiatives both in the United States and abroad, product 

distribution, manufacturer market share, and other manufacturer and industry characteristics. 

BCs and EPSs are typically sold to consumers as components of other end-use products 

(applications). DOE identified more than 80 BC and EPS applications and focused the market 

assessment on the markets for these products for two reasons: 

The demand for applications drives the demand for BCs and EPSs, because BCs and 

EPSs are nearly always integrated into, bundled with, or otherwise intended to be 

used with a given application. 

Because most BCs and EPSs are not stand-alone products, their usage profiles, energy 

consumption, and power requirements are all determined by the associated 

application. 

After identifying the products that use BCs and EPSs, DOE collected data on product 

lifetimes, BC/EPS characteristics, and the number of units shipped annually for sale in the 

United States for these applications. DOE then translated these application-level data to the 

shipments, lifetimes, and performance characteristics of BCs and EPSs themselves. 

2.3.1.1 Bar Code Scanners, Mobile Computers, and Wireless Headphones 

CEA submitted comments on the NOPD regarding standards for non-Class A EPSs in 

which it asked DOE to examine the possibility that EPSs for bar code scanners, ―mobile 

computers,‖ and wireless headphones are MADB EPSs. (CEA, EERE-2009-BT-DET-0005 No. 9 

at p. 2) Upon investigation it appears that bar code scanners and mobile computers with batteries 

intended to be removed for charging are used in the commercial sector and are not consumer 

products. Batteries for wireless headphones do not appear to fit the definition of ―detachable 

battery‖ and, therefore, EPSs used with these products are in Class A. Both the BCs and EPSs 

used with wireless headphones are included in the preliminary analysis. 

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2.3.1.2 Shipments and Lifetimes Estimates 

DOE received several comments related to the product lifetime and shipment estimates 

contained in the draft technical report that accompanied the framework document. PG&E 

commented that DOE, ―significantly underestimated the 2007 sales of EPSs and consumer 

battery chargers in the U.S.‖ (PG&E, No. 20 at p. 11) In a follow-up comment, CEC provided 

DOE with U.S. shipments for several product applications and provided estimates for BC and 

EPS shipments and installed bases. (CEC et al., No. 19 at p. 1) Responding to these comments, 

DOE has expanded the scope of BCs covered and examined more EPS applications since the 

draft technical report was published. DOE also received additional data from PG&E and 

incorporated it into its analysis. DOE estimates that a total of 402 million BCs and 301 million 

EPSs were shipped in 2008 for final sale in the United States. 

DOE received two comments in response to the NOPD on the prevalence of high power 

EPSs. PG&E and CEC both commented that the number of high power EPSs (those with 

nameplate output power greater than 250 watts) is likely to increase in the future as applications 

such as game consoles, fast chargers, and other home electronics demand increasing amounts of 

power. (PG&E, EERE-2009-BT-DET-0005 No. 7 at p. 2; CEC et al., EERE-2009-BT-DET-0005 

No. 8 at p. 1) To date, DOE has identified only one application for high power EPSs, amateur 

radio equipment, but has noted the existence of an LED monitor that uses an EPS with nameplate 

output power of exactly 250 watts. DOE will continue to monitor the market for high power 

EPSs and update its analysis in the NOPR stage. 

BCs and EPSs are designed to outlast their respective applications, and because users 

replace the BC or EPS when they replace an application, DOE assumes BC/EPS lifetimes are 

typically equivalent to the lifetimes of their applications. DOE received support for this 

assumption from interested parties. (PG&E, No. 20 at p. 10) One notable exception to this 

assumption may apply to mobile phones. Several mobile phone manufacturers have agreed to 

adopt the ―GSMA Universal Charging Solution‖ by 2012, which will allow the same EPS to be 

used with multiple phones. This voluntary standard is anticipated to eliminate the need to 

package an EPS with each mobile phone and would result in a longer lifetime for those EPSs. 

More information about the GSMA standard can be found in section 3.2.3 of the TSD. 

2.3.1.3 Properly Representing BCs’ and EPSs’ Paths to Market 

Given the wide array of applications that use BCs and EPSs, the paths to market are 

varied and complex, but typically consist of: (1) component manufacturers, (2) BC/EPS 

manufacturers (sometimes referred to as original device manufacturers or ODMs), (3) end-use 

product manufacturers (sometimes referred to as original equipment manufacturers or OEMs), 

and (4) end-use product retailers/distributors. Not all BCs or EPSs are distributed in the same 

manner. Some follow a less direct path to market, such as those distributed by electrical 

component distributors. Others follow a more direct path to market , such as those BCs 

manufactured in-house by OEMs, which distribute them along with an application. 

DOE presented its models for the distribution channels of BCs and EPSs at the 

framework public meeting in July 2009 and received useful stakeholder comments. AHAM 

explained that the distribution channels for BCs and EPSs are complicated but similar in 

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structure. Differences arise in what share of the market takes which distribution path. Further, 

there are manufacturers of BC applications that sell products both to other manufacturers as well 

as directly to consumers. (AHAM, Pub. Mtg. Tr., No. 14 at p. 231) PTI explained that many enduse product manufacturers (OEMs) do not manufacture the EPS or BC portions of the products 

that they sell, although they may maintain engineering control over the BCs and EPSs. (PTI, 

Pub. Mtg. Tr., No. 14 at p. 240) DOE recognizes the similarities between BC and EPS paths to 

market as well as the complexity of these paths and made changes to its model to better reflect 

the nature of the BC and EPS markets and industries. 

2.3.1.4 Updates to BC and EPS Efficiency Distributions 

In the draft technical report that accompanied the framework document, DOE presented 

its understanding of the efficiency of BCs and EPSs on the market prior to 2008. PG&E 

commented that DOE should update its efficiency distributions to represent the current state of 

the market (PG&E, No. 20 at p. 12) and provided DOE with data from BC tests it conducted. To 

characterize the distribution of BC and EPS shipments by efficiency level in 2009, DOE 

examined data provided by PG&E and from tests DOE performed (see chapter 5). DOE then 

weighted the test data by application shipments to arrive at BC and EPS efficiency distributions. 

The efficiency distributions DOE derived from the bases for the base case efficiency forecasts 

discussed in chapter 9. 

2.3.2 Product Classes 

When necessary, DOE divides covered products into classes by the type of energy used, 

the capacity of the product, and any other performance-related feature that justifies different 

standard levels, such as features affecting consumer utility. (42 U.S.C. 6295(q)) DOE then 

conducts its analysis and considers establishing or amending standards to provide separate 

standard levels for each product class. 

In the framework document, DOE summarized the various product classes used by EISA 

2007, ENERGY STAR, and the draft analysis prepared by DOE for the 2007 determination on 

BCs and EPSs. DOE invited comment from interested parties on the product classes presented 

and also sought suggestions regarding other possible product class-setting criteria that should be 

used in establishing BC and EPS energy conservation standards. 

Although the comments of interested parties concerned only BCs, the criteria proposed 

are in some cases also applicable to EPSs. Therefore, the discussion of the characteristics is 

organized by whether the characteristics can be used to set product classes for both BCs and 

EPSs, BCs only, or EPSs only. These characteristics are listed in Table 2.1. 

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Table 2.1 Class-Setting Characteristics Considered 

Characteristics 

Common to EPSs 

and BCs 

Characteristics Not 

Considered Due to 

Statutory 

Limitations 

Characteristics 

Unique to EPSs 

Characteristics 

Unique to BCs 

Output power Usage Type of power Battery voltage 

Output voltage Topology conversion Battery capacity 

Output cord Price Medical use Battery energy 

length Used with battery 

chargers of 

motorized 

applications and 

detachable 

batteries 

Charge rate 

Battery chemistry 

Inductive coupling 

Cord-cordless 

operation 

Additional 

functionality 

2.3.2.1 Potential Product Class Criteria Applicable to Both BCs and EPSs 

In general, PG&E. commented that DOE should develop a standard that is a continuous 

function (as opposed to discrete steps in standard levels), similar to the EISA 2007 standards for 

EPSs. According to PG&E, standards based on a continuous function would remove the 

incentive to redesign a product that falls near a product class boundary, such that it falls in a 

different product class and is subject to a more lenient standard. (PG&E, No. 20 at p. 7) 

DOE acknowledges this potential for circumvention at the boundary between two product 

classes. Therefore, DOE has sought to minimize the opportunities for circumvention by (1) 

attempting to set the smallest number of product classes while complying with the requirements 

of 42 U.S.C. § 6295(q), and (2) proposing standard levels that—where feasible—are continuous 

across product class boundaries. 

Maximum Output Power. The primary function of both BCs and EPSs is providing 

power; therefore, the main capacity-related characteristic that could be used for setting product 

classes is maximum output power. This parameter determines the sizes of the power-handling 

components of a power converter, and ultimately the size of the converter itself. 

For EPSs, maximum output power is listed on the nameplate. EPSs with greater 

nameplate output power offer the consumer greater capacity and tend to have higher active mode 

average efficiency. EPSs with lower nameplate output power tend to have lower no-load power 

consumption. 

DOE acknowledges that nameplate output power significantly affects utility and 

efficiency and therefore different nameplate output powers may warrant unique product classes. 

However, rather than create distinct product classes by nameplate output power, DOE proposes 

to follow the precedent set by EISA 2007 and ENERGY STAR 2.0 and intends to set an 

efficiency standard level that is a continuous function of nameplate output power for Class A 

EPSs. 

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P C V r MAX BATT BATT

 

 

 

 

 

 

 

PMAX CBATT VBATT r

One of the conditions by which EPCA defines a Class A EPS is that it has ―nameplate 

output power that is less than or equal to 250 watts,‖ hence DOE considers high power EPSs 

with nameplate output power greater than 250 watts to be non-class A EPSs. 

(42 U.S.C. 6291(36)(C)(i)(VI)) The ability to provide power at high wattages is unique to high 

power EPSs. Currently, the most common use of high power EPSs is to power amateur radio 

equipment. Similar to Class A EPSs, DOE intends to set a standard level that is a continuous 

function of nameplate output power for high-power EPSs. 

For BCs, maximum output power limits how quickly a BC can charge a given battery as 

described by the following inequality: 

Eq. 2.1 

Where: 

= the maximum output power, in watts, 

= the battery capacity, in ampere-hours, 

= the battery voltage, in volts, and 

= the charge rate, in units of C or 1/hour. 

AHAM, PTI, and Delta-Q commented that output power should be used as a criterion for 

setting product classes. (AHAM, No. 16 at p. 3; Delta-Q, No. 15 at p. 1; PTI, Pub. Mtg. Tr., No. 

14 at p. 287) AHAM and Delta-Q elaborated by specifying that DOE should place BCs with 

output power greater than 250 watts (AHAM, No. 16 at p. 3) and 1000 watts (Delta-Q, No. 15 at 

p. 1) in separate product classes. 

As mentioned above, output power is a measure of BC capacity; furthermore, BCs with 

different output powers may not be able to meet the same standard in maintenance and nobattery modes. Because output power is a capacity-related characteristic that tends to affect 

efficiency, it meets the requirements of 42 U.S.C 6295(q), and DOE considered it in the 

development of its BC product classes, presented in chapter 3. 

Output Voltage. Many consumer products cannot function on power from mains, which 

is at 115 volts; instead, they rely on power converters to convert mains power to a lower voltage. 

In general, power converters with a higher output voltage will be more efficient. Many of the 

losses that occur in a power converter are functions of current since the current increases as 

voltage decreases for a given output power, as shown in: power (P) = current (I) × voltage (V). 

For EPSs, the output voltage is listed on the device nameplate, and is determined by the 

characteristics of the application. For instance, certain applications such as monitors and printers 

are designed to draw power from an EPS. Their components, such as the LCD screen and print 

engines, have specific voltage requirements that the EPS helps to satisfy by providing power at 

the required voltage. 

ENERGY STAR 2.0 acknowledged that EPSs with lower output voltage are inherently 

less efficient by setting a less stringent level of active mode average efficiency for EPSs with low 

voltage and high current outputs. ENERGY STAR 2.0 defined ―low voltage‖ models as EPSs 

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with nameplate output voltage less than 6 volts and nameplate output current greater than or 

equal to 550 milliamps. ENERGY STAR publishes test results for qualifying EPSs that confirm 

that many low-voltage EPSs would not have qualified at the standard-voltage level.2 In the 

preliminary analysis, DOE set product classes for EPSs with standard voltage output and low 

voltage output. DOE proposes to use the ENERGY STAR criteria to define low voltage EPSs 

because the criteria adequately capture many low-voltage EPSs in the market. 

Nameplate output voltage does not affect EPS no-load mode power consumption because 

there is no output current in no-load mode. Therefore, DOE did not consider the effect of output 

voltage on no-load mode power consumption in setting product classes. 

Most EPSs can only output one voltage at a time, which is a requirement to be considered 

Class A EPSs; however, some multiple-voltage EPSs output power at two or more voltages 

simultaneously. Applications often contain different types of circuits that require different 

voltages. OEMs choose whether to create different voltages within the application or to purchase 

an EPS that provides multiple voltages. Typically, it is more cost-effective to create different 

voltages within the application; however, in some instances manufacturers prefer to use multiplevoltage EPSs. DOE intends to create a separate product class for non-Class A multiple-voltage 

EPSs because of their unique utility. 

For BCs, the power converter output voltage is determined by the voltage of the battery, 

as the BC must output a high enough voltage to fully charge the battery. However, because the 

motors or electronics of the associated end-use product is powered by the rechargeable battery 

have been designed given a particular battery voltage, changing the voltage could severely 

impact consumer utility, forcing the redesign of a product and substitution of motors and 

electronics for perhaps less desirable ones. 

Numerous commenters, including Delta-Q, Wahl, FRIWO, and PTI recommended 

classifying BCs by voltage. (Delta-Q, No. 15 at p. 1; Wahl, No. 23 at p. 2; FRIWO, No. 21 at 

p. 2; PTI, Pub. Mtg. Tr., No. 14 at p. 287) FRIWO further specified divisions between the 

voltage-based product classes based on the cell voltage of the ―currently used rechargeable 

battery chemistry,‖ namely lithium-ion and lithium-polymer. According to FRIWO, batteries 

with voltages at 3.7, 7.4, 11.1, 18.5, 25.9, and greater than 25.9 volts should each be placed in a 

separate product class. (FRIWO, No. 21 at p. 2) On the other hand, PG&E noted that if a BC 

standard allows low voltage products to be less efficient, it will encourage design of less 

efficient, low voltage products, and vice-versa. (PG&E, No. 20 at p. 7; PG&E, Pub. Mtg. Tr., 

No. 14 at p. 302) 

Although PG&E is correct in noting that voltage-based product classes may result in less 

stringent standards and potentially lower the efficiency for low-voltage BCs, such a result may 

be required to ensure consumer utility. In particular, while a stringent standard on (less efficient) 

low-voltage BCs may lead to substitution of higher-voltage BCs for lower-voltage BCs and 

higher BC energy savings, it would also require the redesign of the end-use applications served 

by those BCs. Those end-use applications lie outside of the current scope of this rulemaking. 

Furthermore, in certain applications, the internal voltage of the product will not change 

regardless of the battery voltage. In a notebook computer, for example, the processor voltage 

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must be 1.1 volts. Increasing the BC voltage would only increase the difference between the 

battery voltage and the final processor voltage, which would increase the step-down conversion 

losses inside the computer. Increasing the output voltage would, therefore, decrease the BC 

losses, but may increase the losses in the system as a whole. 

Because battery voltage impacts both the efficiency and utility of a BC, DOE will 

consider it as a criterion for setting product classes. Furthermore, DOE agrees with FRIWO that 

any divisions between voltage-based product classes should take into account the voltages of the 

most common batteries, though whether these divisions should fall every 3.7 volts or more or 

less frequently (e.g., every 1.2 volts to accommodate nickel-based chemistries) is discussed 

further in section 2.3.2.3. 

Output Cord Length. The length of the output cord affects both utility and efficiency: 

longer output cords offer consumers more utility, so that they have more reach between the wall 

adapter and the application. However, increasing cord length increases power loss and lowers 

efficiency. In its comments, Wahl noted the length and stranding of the cord has an impact on the 

BC efficiency (Wahl, No. 23 at p. 1), and should therefore be considered as a possible criterion 

for setting product classes. 

The output cord of an EPS can have an appreciable impact on its measured efficiency due 

to resistive losses in the conductors. For example, DOE tests indicate that an output cord can 

cause a 120-watt EPS’s average efficiency to drop 0.8 percentage points, up to a maximum of 

1.97 percentage points. This amount is significant in the EPS analysis, where a few percentage 

points separate the most and least efficient units in the market at a given output power level. 

The losses in the cord, and hence the efficiency of the EPS, are also affected by its crosssectional area. Specifically, the resistance of the output cord is proportionally related to the 

inverse of its cross-sectional area: R ∝ 1 / A (where R is resistance, ∝ is the proportionality 

symbol, and A is area). Although a thicker cord may be heavier, bulkier, and less flexible in 

theory, no significant variations have been encountered in practice. DOE does not expect the 

small variations to affect consumer utility. 

DOE accounted for differences in output cord length through scaling when analyzing 

EPS test data, teardown data and manufacturer data. However, DOE did not account for output 

cord length when setting CSL efficiency equations for EPSs because the wide variety of output 

cord lengths render it impractical to do that. DOE proposes not to include output cord length as a 

factor in determining CSL equations. 

In the BC analysis, output cord length and thickness were not taken into account because 

even a 1.97 percentage point decrease in efficiency stemming from output cord losses is not 

significant when compared to the active-mode efficiency, which can vary by 30 percentage 

points or more across units of a single product class, and the annual energy consumption 

(including energy consumption in all modes), which can vary by a factor of more than10. 

Usage, Topology, and Price. Unlike some of the other products regulated by DOE 

through energy conservation standards, BCs and EPSs are rarely the end-use application. This 

fact is reflected, in part, by the statutory definition for BCs, which includes ―battery chargers 

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embedded in other consumer products‖ in the BC definition. (42 U.S.C. § 6291(32)) Similarly 

the EPS definition specifies that an EPS ―is used . . . to operate a consumer product.‖ (42 U.S.C. 

§ 6291(36)) As a result, the type of application that the BC or EPS serves, and in particular how 

that application is used may also differentially impact the energy consumption of BCs and EPSs 

in addition to the capacity- and utility-related characteristics described above. Both Wahl and 

AHAM emphasized this fact by urging DOE to consider usage patterns when setting product 

classes. AHAM also requested that DOE only consider minimal no-battery and maintenance 

time when analyzing infrequently-used BCs. (Wahl, No. 23 at p. 2; AHAM, No. 16 at p. 4) 

During the framework document public meeting, interested parties also commented on 

the role BC topology should play in the preliminary analysis. Topology is a term used to describe 

the general architecture of the power conversion stage of a BC. The choice of topology is 

affected by considerations such as output voltage, output power, reliability, and even the 

experience of the designer. While the topologies do not constrain the efficiency of a power 

converter and its associated BC, they influence the choice of technology options for increasing 

efficiency and affect the cost of efficiency improvement from the baseline. Because of the wide 

variety of applications and limited time for analysis, PG&E recommended that DOE focus on 

analyzing unique topologies and associated technology options instead. (PG&E, Pub. Mtg. Tr., 

No. 14 at p. 58) PTI, however, commented that since topology is transparent to consumers and 

consumers do not buy products based on topology, it may not be a good criterion to consider for 

product classes. (PTI, Pub. Mtg. Tr., No. 14 at p. 286) 

Finally, Wahl commented that DOE should also consider the retail price of a BC when 

creating product classes. (Wahl, No. 23 at p. 2) 

Unlike the characteristics discussed previously, usage, topology, and price do not meet 

the statutory criteria for setting separate standard levels for product classes under 42 U.S.C. 

6295(q). In particular, although these characteristics may differentially impact the efficiency of 

BCs and EPSs, they do not impact their capacity or utility; instead, price and topology are 

impacted by the capacity- and utility-related features of a BC or EPS. By setting product classes 

based directly on those features, as suggested above, DOE will also be taking into account the 

effects of topology and price, while complying with the requirements of 42 U.S.C. 6291(q). 

Finally, usage is not a characteristic of a BC or an EPS, but rather the end-use application 

it serves. Therefore, even if a BC or EPS consumes more energy due to pairing with a heavily 

used application, nothing prevents it from being paired with a lightly used application, and viceversa, as long as the two power converters have the same utility. 

2.3.2.2 Potential Product Class Criteria Applicable Only to EPSs 

Type of Power Conversion (AC/AC versus AC/DC). All EPSs receive input power from 

mains in the form of alternating current (AC) and provide output power in the form of either AC 

power or direct current (DC) power. This is another key functionality of an EPS, along with 

providing power at a specific voltage. Again, the type of power conversion the EPS provides is 

governed by its application. Applications such as mobile phones and laptops require DC power 

to match the type of power provided by the battery. Applications that tend to use EPSs that 

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provide AC power, such as cordless phones, often have conversion circuitry within the 

application for AC-DC conversion. 

The type of power conversion is indicative of an EPS’s internal circuitry, therefore its 

capability to conserve energy. EPSs that provide AC output power typically contain only a 

transformer. The no-load power losses of those EPSs are dominated by transformer core losses. 

Alternatively, EPSs that provide DC power output typically contain a transformer as well as 

overhead circuitry that control the flow of power through the EPS. Overhead circuitry provides 

EPSs that function using DC-output power with the ability to reduce power consumption in noload mode in contrast to AC-output EPSs that typically cannot. Technically, it is possible to add 

overhead circuitry to an EPS with AC output power to reduce EPS power consumption in noload mode; however, the overhead power consumption of that circuit would most probably 

outweigh potential energy savings from the rest of the EPS. ENERGY STAR 2.0 acknowledges 

this relationship by setting a less stringent level of no-load mode power consumption for EPSs 

with AC output power. Although DOE did not receive comments from interested parties related 

to EPS conversion type, DOE set different product classes for EPSs with AC output power and 

DC output power in the preliminary analysis. 

Use with Medical Equipment. Another condition by which EPCA defines a Class A EPS 

is that it does not include any device that ―requires Federal Food and Drug Administration listing 

and approval as a medical device in accordance with section 513 of the Federal Food, Drug, and 

Cosmetic Act (21 U.S.C. § 360c).‖ (42 U.S.C. § 6291(36)(C)(ii)(I)) Thus, all EPSs used with 

medical devices must meet the special requirements of UL standard 60601, such that they are 

approved by the Federal Food and Drug Administration (FDA)c

. Use with medical devices is a 

utility that is unique to medical EPSs, which are exempted from EISA 2007 efficiency standards. 

Consequently, there may be medical EPSs in the market with efficiencies lower than required by 

EISA 2007 for Class A EPSs. In the non-Class A EPS determination analysis, DOE tested two 

medical EPSs as well as four Class A EPSs that DOE tentatively identified as being 

electronically equivalent to medical EPSs. Of those six EPSs, only one of the Class A EPSs had 

an efficiency level lower than that required by EISA 2007. DOE is considering testing more 

medical EPSs for the NOPR analysis to further characterize the distribution of efficiency levels 

in the medical EPS market. 

Use with Battery Chargers of Motorized Applications and Detachable Batteries. EPCA 

also excludes from the Class A EPS definition any device that powers the charger of a detachable 

battery pack or charges the battery of a product that is fully or primarily motor operated.‖ 

(42 U.S.C. 6291(36)(C)(ii)(II)) By extension, these devices are exempted from having to meet 

the efficiency standards for Class A EPSs set by EISA 2007. Examples of products that are fully 

or primarily motor operated include portable rechargeable household appliances such as 

handheld vacuums, personal care products such as shavers, and power tools. DOE considers 

EPSs for ―battery chargers of motorized applications and detachable batteries" (MADB EPSs) to 

have a unique utility from Class A EPSs because EISA 2007 excluded them from Class A EPS 

coverage. 42 U.S.C. § 6291(36)(C)(ii). Because there are no required efficiency levels for these 

c Underwriters Laboratories standard for power supplies for medical devices. More information on UL 60601 and 

how it applies to medical EPSs is presented in section B. Scope of the Notice of Proposed Determination (NOPD) 

for non-Class A EPSs published on May 14, 2010. 74 FR 56928. 

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EBATT CBATT VBATT

 

 

 

 

types of EPSs, DOE believes at this time that MADB EPSs have efficiencies lower than those 

established for Class A EPSs. In the non-Class A EPS determination analysis, DOE tested 12 

Class A EPSs that it believed were electronically equivalent to MADB EPSs. Of those 12 EPSs, 

only two of the Class A EPSs had efficiency levels lower than that required by EISA 2007. DOE 

is considering testing MADB EPSs for the NOPR to further characterize the distribution of 

efficiency levels in the MADB EPS market. 

2.3.2.3 Potential Product Class Criteria Applicable Only to BCs 

Battery Capacity. Similar to battery voltage, battery capacity impacts utility as well as 

BC output power, the primary capacity-related characteristic of the BC. A battery with half the 

capacity of another will power the same consumer product half as long. Wahl and PTI both 

recommended that battery capacity could be used for setting product classes. (PTI, Pub. Mtg. Tr., 

No. 14 at p. 287; Wahl, No. 23 at p. 1) However, Wahl also commented that any variations in 

efficiency due to battery capacity could also be addressed in the test procedure. (Wahl, No. 23 at 

p. 1) Although the commenter did not specify how, one possible method could involve 

normalizing the energy consumption result by the battery capacity. 

Neither the current nor proposed DOE test procedure for battery chargers normalizes the 

energy consumption of the battery charger by battery capacity. Therefore, any capacity-related 

differences in energy consumption would have to be addressed through different standard levels 

for each capacity-related product class. Because battery capacity impacts both the efficiency of 

the BC and its utility, it can be used to establish product classes, and is discussed further in 

chapter 3. 

Battery Energy. Battery energy is the product of battery capacity and battery voltage as 

described below: 

Eq. 2.2 

Where: 

EBATT CBATT VBATT

= the battery energy in watt-hours, 

= the battery capacity, in ampere-hours, and 

= the battery voltage, in volts. 

Battery energy combines the effects of both battery capacity and voltage; PG&E. 

suggested that this characteristic is most indicative of a battery charging system's actual utility. 

(PG&E, No. 20 at p. 7) PTI joined PG&E. in recommending that battery energy be used to set 

product classes. (PTI, Pub. Mtg. Tr., No. 14 at p. 287) 

As with both battery voltage and battery capacity, battery energy is an important battery 

charger characteristic that impacts not only BC efficiency but also BC utility and capacity (e.g., a 

charger redesigned to charge a higher-energy battery in the same amount of time would see an 

increase in output power). It merits further consideration because, as noted by PG&E, it 

determines the amount of work that an end-use consumer product can perform, regardless of the 

specifics of BC or application design. As described later in chapter 3, DOE used battery energy 

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as a proxy for the other potential product-class-setting characteristics, such as maximum output 

power and battery capacity. 

Charge Rate. Charge rate is equal to the charge current (in amperes) normalized by the 

battery capacity (in ampere-hours), and reflects the speed at which a battery is being charged. 

Under ideal conditions (i.e., ignoring cell inefficiency and cell equalization or other additional 

charging steps), the charge time would be the inverse of the charge rate, which is expressed in 

units of C or 1/hours. 

Comments from interested parties diverged on whether to set product classes based on 

charge rate. PG&E argued against a separate product class for slow (i.e., low-charge-rate) 

chargers out of concern that a separate class would permit less efficient BCs despite the 

availability of the technology improvement options for fast chargers that DOE listed in the 

framework document could also be cost-effectively implemented in slow chargers. (PG&E, No. 

20 at pp. 6 and 8) Wahl also commented that charge rate should not be used to create product 

classes, despite its important role in BC design. (Wahl, No. 23 at pp. 1–2) Conversely, PTI and 

AHAM spoke in favor of product classes based on charge rate, because it is more costly to 

increase the efficiency of slow chargers than that of fast chargers. (AHAM, Pub. Mtg. Tr., No. 

14 at pp. 309; PTI, Pub. Mtg. Tr., No. 14 287) 

Charge rate affects the output power of the charger. For a given battery voltage and 

capacity, a faster charger has a higher charge rate, and therefore a higher output power. This 

relationship corresponds to a higher capacity for the purposes of this discussion, as the charger 

can transfer more energy to the battery per unit time. 

However, as mentioned above, output power also depends on the voltage, capacity, 

and/or energy of the battery. Furthermore, the variation in output power due to the battery 

parameters is much greater than that due to charge rate, as charge rates rarely fall outside the 

range of 0.1 C to 1 C, while battery energies can span over five orders of magnitude from less 

than 1 watt-hour to over 10,000 watt-hours. Because of its more limited effect on output power, 

it is more accurate to consider charge rate as a utility characteristic. A BC with a higher charge 

rate will charge the battery in less time, providing greater utility to the user. 

Fast chargers, which have higher capacities and provide greater consumer utility, also 

tend to be more efficient than slow chargers. Fast chargers typically use switched-mode power 

supplies that have lower transformer core losses than slow chargers incorporating line-frequency 

transformers followed by a rectifier. Additionally, slow chargers generally do not have 

monitoring and cutoff circuitry. The lack of this circuitry means that once a battery is fully 

charged, slow chargers tend to deliver excess current to the battery, which causes maintenance 

mode power consumption to increase and further decreases efficiency. 

Furthermore, with respect to the comments regarding technology options—i.e., whether 

technology options exist to make slow chargers as efficient as fast chargers—the information 

available to DOE indicate that slow chargers do not provide any appreciable benefits when 

compared to fast chargers. This observation, when coupled with the fact that slow chargers can 

be readily replaced with fast chargers for the same applications, tends to support the view that 

there is insufficient justification to support the creation of a separate product class based on 

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charge rate. As the name suggests, slow chargers tend to take longer to charge the same battery 

as a fast charger and thus provide less utility to the consumer. DOE notes that replacement costs 

are factored in its engineering analysis described later in chapter 5. Accordingly, in developing 

its product class discussion found in Chapter 3, DOE did not consider classes based on charge 

rates. Finally, because slow chargers do not provide any unique utility to consumers relative to 

fast chargers, DOE cannot set less stringent standards for slow chargers under 42 U.S.C. 

6295(q). 

Battery Chemistry. Battery chemistry is another term for the battery composition—i.e., 

the materials that serve as the electrodes and electrolyte of the electrochemical cell. The 

properties of these materials determine the cell voltage, cell efficiency, self-discharge rate, and 

other properties of the battery. They also affect the design of the BC, including the detection of 

charge completion, the need for termination (i.e., significantly decreasing the charging current 

following full charge), and the extent of safety circuitry. Despite the impacts of battery chemistry 

on the design of the battery charging system, Wahl commented that battery chemistry should not 

be used to create product classes. (Wahl, No. 23 at p. 3) PTI disagreed, stating that lithium-based 

chemistries should be differentiated from older chemistries. (PTI, Pub. Mtg. Tr., No. 14 at 

p. 287) 

Battery chemistries differ in, for example, energy density and maximum discharge 

current, which can result in differences in consumer utility such as the length of time that a 

battery can be stored between recharges, the weight of the battery, or the maximum mechanical 

power output from a mechanical appliance, respectively. Nonetheless, the actual impact on users 

of consumer products is minor. For example, power tools, shavers, and electric toothbrushes can 

use both lithium- and nickel-based battery chemistries with some redesign. Nonetheless, there 

are applications that rely on only one type of battery chemistry, e.g., golf cars (which use leadacid), cordless telephones (nickel-metal hydride), and cellular telephones (lithium ion). 

In the case of golf cars, the lead-acid chemistry is used because it is the only chemistry 

that satisfies the requirements of the application, such as battery voltage and energy 

requirements. In that case, those primary capacity and utility characteristics can serve as a proxy 

for battery chemistry, and as long as DOE accounts for those other characteristics, it will also 

take into account any further effects of battery chemistry. In the case of cordless and cellular 

telephones, where the two applications have similar battery voltage and energy requirements, 

among others, it appears that the difference in battery chemistry is primarily a function of cost 

and historical preference. Cellular telephones tend to be costlier, so manufacturers can better 

afford the cost of a more expensive lithium-ion battery. This cost can be accounted for in the 

engineering analysis, which examines the cost differences associated with energy efficiency. 

Additional differences between nickel- and lithium-based chemistries can be treated 

similarly to the differences between slow and fast chargers. Because lithium-based batteries tend 

to be more energy-dense and have lower self-discharge, they provide additional consumer utility, 

similar to fast chargers. However, like fast chargers, lithium-based BCs also tend to be more 

efficient than nickel-based BCs. As a result, even if stringent DOE standards were to limit the 

number of nickel-based BCs in the market, doing so would not reduce consumer utility. For the 

reasons described above, differences in battery chemistry do not warrant the establishment of 

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separate standards under 42 U.S.C. § 6295(q), and have therefore not been considered in the 

establishment of BC product classes detailed in chapter 3. 

Inductive Coupling. Inductively coupled BCs do not use a galvanic (i.e., currentcarrying) connection to transfer power from the DC or AC-line input to the battery; rather, a coil 

in the charging cradle transmits power via a magnetic field to a similar coil embedded in the 

enclosure containing the remainder of the charger, the integral battery, and the end-use 

application. These types of chargers have been typically used for electric toothbrushes, but have 

also recently been introduced for use with notebook computers. 

AHAM, Philips, and Wahl all commented that DOE should establish a separate product 

class for inductively-coupled chargers. (AHAM, No. 16 at p. 4; AHAM, Pub. Mtg. Tr., No. 14 at 

p. 124; Philips, No. 22 at p. 2; Wahl, No. 23 at p. 2) They stated consumer benefits of inductive 

chargers include safety and cleanliness. By separating the cradle from the rest of the system with 

two layers of plastic, and transferring power to the battery through magnetic induction, designers 

ensure isolation from wall current. This can be important in a wet environment where most 

inductive chargers are used; however, it is worth noting that most BCs provide galvanic isolation 

through a transformer enclosed inside a wall adapter. This design decreases the likelihood of 

shock by distancing non-isolated line-voltage AC from the user and the wet environment. This 

design can be found in BCs for a number of other applications used in wet environments 

including shavers, trimmers, and even dental irrigators, which are subject to the same usage 

conditions as toothbrushes. 

Nonetheless, the commenters imply that metal contacts tend to corrode in a wet 

environment (which would potentially cause loss of contact between parts of the system and 

require frequent cleaning). Because these events may impact consumer utility, DOE considered 

inductive charging for applications used in wet environments when developing product classes in 

chapter 3. DOE did not consider separate product classes for inductive chargers used with other 

applications (such as notebook computers), since they confer no safety or cleanliness advantages. 

Cord-Cordless Operation. Cord-cordless products (e.g., shavers or laptop computers) are 

―dual-function‖ BC products that can use the wall adapter to both recharge the battery as well as 

power the product directly in case the battery is discharged. For example, a user typically 

recharges the battery of a shaver through a wall adapter, disconnects the wall adapter, and then 

powers the shaver from the battery. However, if the shaver is cord-cordless, the user need not 

wait for the battery to recharge and can alternatively power the shaver directly from the wall 

adapter. 

Because the wall adapter must be able to supply power to the application directly, the 

power conversion circuitry has a higher capacity (i.e., output power) than that required to 

recharge a similar-sized battery in the absence of cord-cordless operation. Nonetheless, because 

this capacity is unrelated to battery charging, DOE views cord-cordless operation as a 

characteristic that impacts utility. Both AHAM and Wahl commented that DOE should consider 

cord-cordless operation when setting product classes. (AHAM, No. 16 at p. 4; Wahl, No. 23 at 

p. 1–2; Wahl, Pub. Mtg. Tr., No. 14 at p. 291) 

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The additional power converter capacity necessary to support cord-cordless operation 

will result in higher fixed losses (e.g., higher hysteresis losses for larger transformers). 

Specifically, the efficiency of a dual-function system operating far below its design capacity in 

battery charging mode will never be as high as that of an optimally scaled single-function 

system. This can be seen in the typical relationship between output power and efficiency for an 

EPS. When an EPS outputs power above 25 percent of maximum rated output power its 

efficiency tends to be much higher than when it outputs power below 25 percent of maximum 

rated output power. The reason for this is that at low load (less than 25 percent of maximum 

rated output power) an EPS’s fixed losses from overhead circuitry are a significant portion of 

total losses. 

Nonetheless, manufacturers can employ a variety of techniques to improve the efficiency 

of a BC designed for cord-cordless operation. This is evident from other BC systems that tend to 

operate far below their maximum rated output power. For example, notebook-computer BCs tend 

to outperform BCs for other applications such as power tools, despite the fact that notebookcomputer BCs tend to operate at a far lower level of their maximum capacity than do power tool 

BCs. Therefore, because there is no systematic efficiency penalty to using a cord-cordless 

system, there is no need to set different standards to protect the utility offered by these BCs. 

Hence, DOE did not consider cord-cordless operation in the development of BC product classes 

presented in chapter 3. 

Additional Functionality. Besides cord-cordless operation, manufacturers may include 

in the BC product additional features unrelated to battery charging. These features result in 

higher energy consumption when compared to similar BCs, leading Wahl to comment that DOE 

should consider establishing separate product classes for BCs with additional functionality such 

as an embedded radio, etc. (Wahl, No. 23 at p. 2) PG&E commented that standards should 

encourage manufacturers to include an off switch for additional functionality, rather than a free 

pass to consume excess energy. (PG&E, Pub. Mtg. Tr., No. 14 at p. 294) Similarly, PG&E 

suggested that DOE should not allow battery chargers to consume energy for additional 

functions. (PG&E, No. 20 at p. 17) 

It is possible to categorize BCs with additional functionality into two non-exclusive 

groups based on whether the additional functionality is due to connections with other systems 

(e.g., cordless telephone base) or due to user interaction (e.g., power tool charger radio). 

The first type of additional functionality is exemplified by cordless telephone bases that 

monitor the state of the telephone line and/or store voicemail messages. These types of devices 

provide an added utility through connection with other systems, e.g., the telephone line. Because 

the additional functionality relies on the connection to other parts of the system, manufacturers 

can use disconnection (required by the proposed BC active mode test procedure) as a signal to 

turn off the additional functionality and reduce power consumption to the level of BCs without 

the additional functionality. 

The second type of additional functionality is exemplified by a power tool charger radio 

that provides an interface for operation by the user. Because this type of device already relies on 

users to operate it, a manufacturer should be able to add or repurpose one of the interface 

elements to allow a user (and tester) to turn off the additional functionality of the device, 

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reducing its power consumption to a level comparable with BCs and EPSs without the additional 

functionality. 

In either case, the energy consumption of the additional functionality can be substantially 

reduced through design features that disable the additional functionality when not needed, 

reducing the energy consumption of the BC to the level of similar BCs without additional 

functionality. DOE is addressing this issue through its BC active mode test procedure 

rulemaking, where it is currently proposing to require that all BC efficiency tests to be conducted 

with auxiliary cables disconnected and user switches turned off. Because these test conditions 

can be easily detected by the microcontroller operating the BC, designers should be able to 

power down the additional functionality. As a result, such BCs likely do not have a higher level 

of energy consumption and DOE did not consider additional functionality as a factor in setting 

product classes. 

DC Input Voltage Type. While not explicitly mentioned in the comments of interested 

parties, another potential characteristic that can be used for setting product classes is the input 

voltage to the BC. Whereas many BCs receive power from AC mains, DOE has identified 

numerous BCs for applications such as portable media players, personal data assistants (PDAs), 

and in-car satellite navigation units that draw power from a low-voltage DC source rather than 

the high-voltage AC line. In particular, manufacturers of these products do not typically package 

a wall adapter, instead expecting users to recharge them using a personal computer’s USB port or 

a car’s cigarette lighter receptacle. 

Because a rechargeable battery requires direct current (DC) to charge, BCs with linevoltage AC input must include AC-DC conversion; in contrast, BCs with low-voltage DC input 

can forgo this step, potentially attaining higher efficiencies. Because input voltage can have a 

differential impact on BC efficiency and, furthermore, because input voltage determines where 

the BC can be used, which would impact the product’s utility, DOE is considering using this 

characteristic to set product classes. 

AC Output. While most BC applications draw direct current (DC) directly from the 

battery or through a DC-DC converter, uninterruptible power supplies (UPSs) differ in that they 

use an DC-AC converter to provide an AC output from the battery. This difference in design is 

required by the end-use applications that are connected to the UPS-devices, such as desktop 

computers, monitors, and network equipment. All of these devices typically require line-voltage 

AC output. 

The additional circuitry required to perform this AC-DC conversion consumes additional 

energy even when no applications are connected. Therefore, DOE is considering placing these 

BCs in a separate product class. 

2.3.2.4 EPS Product Classes under Consideration 

For all the reasons discussed above, DOE is considering the EPS product classes listed in 

Table 2.2, Table 2.3, Table 2.4, Table 2.5, and Table 2.6. Under these product classes, an EPS’s 

product class is first determined by whether it is Class A or non-Class A and then by its type of 

power conversion, its output voltage(s), and/or its output power. For Class A, medical, and 

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MADB EPSs DOE proposes using the same criteria as ENERGY STAR 2.0 to distinguish low 

voltage EPSs from basic voltage EPSs. Within each product class, the efficiency standard level 

will vary with nameplate output power but not output cord length. Chapter 3 of this preliminary 

TSD provides additional detail on the selection product classes. 

Table 2.2 Class A EPS Product Classes 

Basic Voltage Output Low Voltage Output * 

AC-DC Conversion 

AC-AC Conversion 

A1 

A3 

A2 

A4 * Low voltage output EPSs have nameplate output voltage less than 6 volts and nameplate output current greater than 

or equal to 550 milliamps. All other EPSs are basic voltage output. 

Table 2.3 Multiple Voltage EPS Product Classes 

# 

Nameplate Output Power < 100 watts 

Nameplate Output Power ≥ 100 watts 

X1 

X2 

Table 2.4 High Power EPS Product Classes 

# 

Nameplate Output Power > 250 watts H1 

Table 2.5 Medical EPS Product Classes 

Basic Voltage Output Low Voltage Output * 

AC-DC Conversion 

AC-AC Conversion 

M1 

M3 

M2 

M4 * Low voltage output EPSs have nameplate output voltage less than 6 volts and nameplate output current greater than 

or equal to 550 milliamps. All other EPSs are basic voltage output. 

Table 2.6 MADB EPS Product Classes 

Basic Voltage Output Low Voltage Output * 

AC-DC Conversion 

AC-AC Conversion 

B1 

B3 

B2 

B4 * Low voltage output EPSs have nameplate output voltage less than six volts and nameplate output current greater 

than or equal to 550 milliamps. All other EPSs are basic voltage output. 

2.3.2.5 BC Product Classes Under Consideration 

Based on the above discussion of potential product class criteria for BCs, DOE took into 

account the following capacity- and utility-related characteristics when setting product classes: 

output power;
 

battery voltage;
 

battery capacity;
 

battery energy;
 

inductive charging;
 

input voltage (line AC or low-voltage DC); and
 

AC output.
 

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Following additional analysis, detailed in chapter 3 and summarized below, DOE decided 

to base its product classes for the preliminary analysis on battery energy and battery voltage, as 

well as input voltage (line AC versus DC) and additional functionality (inductive charging and 

AC output). 

Although output power is the BC characteristic most indicative of BC capacity, battery 

voltage, capacity, and energy all impact output power and all relate to BC utility. Of these, 

battery energy has both the biggest impact on output power and is also the most meaningful 

indicator of utility, measuring the total useful work that can be performed by a charged battery. 

Consequently, DOE selected this characteristic to help establish product classes in the 

preliminary analysis. 

However, as mentioned in section 2.3.2.1 above, the battery voltage provides an 

additional measure of utility by constraining the end-user applications that a particular battery 

can power. Because of its importance to consumers and impact on BC efficiency, DOE selected 

battery voltage for setting product classes in the preliminary analysis. Additional characteristics 

selected for setting product classes included inductive charging, input voltage, and AC output. 

Because there are many possible combinations of battery voltage and energy, DOE 

decided to group BCs into several product classes based on their underlying topology, or design. 

BCs for low-energy batteries typically use line-frequency or flyback topologies; BCs for 

medium-energy batteries typically use forward or half-bridge topologies; while BCs for highenergy batteries typically use full-bridge or ferro-resonant topologies. These underlying 

topologies impact the technology options that can be used for improving the energy efficiency of 

the BC, such that an analysis on a BC of a particular topology can be reliably applied to others of 

that same topology to the entire product class. 

While battery voltage also impacts the choice of technology options, its impact is not as 

great as battery energy. To address this impact, DOE further divided some BCs into high-, low-, 

and where applicable, medium-voltage product classes. The product classes appear in Table 2.7. 

DOE did not separate certain classes by voltage for which only a single application exists on the 

market because those classes each have only one voltage. 

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Table 2.7 BC Product Classes Used in the Preliminary Analysis. 

Product Class 

# Description Example Applications 

AC 

In, 

DC 

Out 

< 100 

Wh 

Inductive 

Connection 1 Low Energy, Inductive Toothbrushes 

<4 V 2 Low Energy, 

Low Voltage Telephones 

4–10 V 3 Low Energy, 

Med. Voltage 

Cameras and Small 

Tools 

>10 V 4 Low Energy, 

High Voltage 

Laptops and Large 

Tools 

100– 

3000 Wh 

<20 V 5 Med. Energy, 

Low Voltage 

Marine Chargers, 

Wheelchairs 

≥20 V 6 Med. Energy, 

High Voltage 

Electric Bikes, 

Lawnmowers 

> 3000 Wh 7 High Energy Golf Cars 

DC In, 

DC Out 

<9 V Input 8 

Low Energy, 

Low Voltage DC 

Input 

USB Chargers 

≥9 V Input 9 

Low Energy, 

High Voltage DC 

Input 

Car Chargers 

AC In, 

AC Out 

AC Output from 

Battery 10 Low Energy, AC Output 

Uninterruptible Power 

Supplies 

2.3.3 Technology Assessment 

In the technology assessment, DOE identifies technology options that appear to be a 

feasible means of improving product efficiency. This assessment provides the technical 

background and structure on which DOE bases its screening and engineering analyses. The 

following discussion provides an overview of the salient aspects of the technology assessment, 

including issues on which DOE seeks public comment. Chapter 3 of the preliminary TSD 

provides detailed descriptions of the basic construction and operation of BCs and EPSs, followed 

by a discussion of technology options to improve their efficiency and power consumption in 

various modes. 

2.3.3.1 EPS Efficiency Metrics 

On December 8, 2006, DOE codified a test procedure final rule for EPSs in Appendix Z 

to Subpart B of 10 CFR Part 430 (―Uniform Test Method for Measuring the Energy 

Consumption of External Power Supplies.‖) 71 FR 71340. DOE’s test procedure, based on the 

California Energy Commission (CEC) EPS test procedure, yields two measurements: activemode efficiency and no-load-mode (standby-mode) power consumption. 

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Active mode conversion efficiency is the ratio of output power to input power. The DOE 

test procedure averages the efficiency at four loading conditions—25, 50, 75, and 100 percent of 

maximum rated output current—to assess the performance of an EPS when powering diverse 

loads. The test procedure also measures the power consumption of the EPS when disconnected 

from the consumer product, which is termed no-load power consumption. Because both the 

average efficiency and no-load power consumption affect the energy consumption of the EPS, 

DOE developed CSLs for the engineering analysis that are ―matched pairs‖ of limits on both 

metrics simultaneously. 

To develop the analysis and ultimately to set standards for EPSs, DOE can either 

combine the test values into a single metric, such as annual energy consumption, or it can 

maintain two separate metrics. For this preliminary analysis DOE has chosen to evaluate EPSs 

using the two metrics separately. DOE believes this approach is the most appropriate way to 

characterize EPSs because these products have a wide variety of usage profiles that would affect 

any weighting of average efficiency and no-load power. Adopting an integrated approach would 

depart from the precedent established by EISA 2007, possibly allowing for ―backsliding‖ 

because a combined metric would limit the overall energy consumption of the EPS, which could 

allow for one metric to be below EISA standards if the other metric sufficiently exceeded 

standards. Further, this approach is important because the cost estimates in the engineering 

analysis apply to the EPS as a whole. . DOE created ―matched pairs‖ of efficiency to evaluate 

CSLs, test data, and manufacturer data. In the matched pairs approach EPS power consumption 

improves either through higher active-mode efficiency, lower no-load mode power consumption, 

or both. 

On April 2, 2010, DOE proposed a test procedure for multiple-voltage EPSs that would 

yield five values: no-load power consumption as well as efficiency at 25, 50, 75, and 100percent 

of maximum load. 75 FR 16958, 16974. DOE proposes to integrate these four efficiency values 

into an average efficiency metric in the standard. Specifically, DOE proposes to use the no-load 

power consumption and an average of the four efficiency values as metrics to set candidate 

standard levels for multiple-voltage EPSs, similar to single-voltage EPSs. Alternatively, DOE is 

also considering approaches to integrate the four active mode measurements in a way to help 

better indicate the efficiency of multiple-voltage EPSs during typical use. For instance, DOE 

could average only the efficiency values at 50 percent and 75 percent. See Microsoft, 

EERE‐2008‐BT‐TP‐0004 No.8 at p. 1-2. Overall, DOE faces the same challenge with multiplevoltage EPSs as it does with single-voltage EPSs: products change continuously, which means 

the test metric should be robust enough to be valid to all applicable products. As noted in the 

executive summary, DOE is seeking stakeholder comment on alternative methods for using the 

five metrics to set candidate standard levels for EPSs. 

2.3.3.2 EPS Technology Options 

In the framework document, DOE requested comments on a list of preliminary 

technology options that DOE intended to study further. For EPSs, these technology options 

included: 

Improved Cores 

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Switched-Mode Power Supply 

Low-Power Integrated Circuits 

Schottky Diodes and Synchronous Rectification 

Low-Loss Transistors 

Low-Loss Snubbers 

Interested parties did not provide comment on the technology options proposed in the 

framework document nor suggest additional technology options for DOE to consider. Additional 

information on these technology options is available in chapter 3. 

2.3.3.3 BC Efficiency Metrics 

As described in section 2.1.2.2, DOE has adopted a test procedure for BCs in appendix Z 

to subpart B of 10 CFR part 430. In a related rulemaking, DOE is currently updating this test 

procedure to accommodate measurement of active mode energy consumption, and the proposed 

test procedure will return four metrics, related to each mode of operation of a BC: active, 

maintenance, standby, and off. 

At the framework document public meeting, DOE expressed its intention of weighting 

these mode-specific metrics using a product-class average usage profiled to calculate the annual 

energy consumption of a BC. These weights would be calculated during the standard-setting 

stage of the rulemaking. 

PTI and AHAM commented that a BC standard should incorporate a usage profile. (PTI, 

Public Meeting Transcript, No. 14 at p. 249; AHAM, Public Meeting Transcript, No. 14 at 

p. 251) PG&E disagreed, noting that while duty cycle estimates are needed to calculate energy 

use and savings, they should not be used to create a standard metric. (PG&E, No. 20 at p. 9) 

Furthermore, standards expressed in terms of separate metrics would ensure that all operational 

modes are efficient. (PG&E, No. 20 at p. 6) Finally, PG&E believed that it would be difficult to 

develop appropriate usage profiles as there is insufficient data to arrive at a ―realistic and 

creditable understanding.‖ (PG&E, Pub. Mtg. Tr., No. 14 at pp. 161,and 159; PG&E, No. 20 at 

p. 15). PG&E stated that DOE should rather defer the creation of appropriate usage profiles to 

future rulemakings once more data have been obtained. (PG&E, Pub. Mtg. Tr., No. 14 at p. 178) 

DOE is obligated to create an integrated measurement of overall energy consumption, if 

possible. Section 325 of EPCA, as modified by EISA 2007, requires the results of a standby 

measurement to be: 

d The calculation of product-class-average usage profiles and the calculation of typical energy consumption is 

described in detail in the energy use and end-use load characterization (chapter 7). 

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integrated into the overall energy efficiency, energy consumption, or other energy descriptor 

for each covered product unless the Secretary determines that— 

(i)	 the current test procedures for a covered product already fully account for and 

incorporate the standby mode and off mode energy consumption of the covered product; 

or 

(ii) such an integrated test procedure is technically infeasible for a particular covered 

product, in which case the Secretary shall prescribe a separate standby mode and off 

mode energy use test procedure for the covered product, if technically feasible. (42 

U.S.C. 6295(gg)(2)(A)) 

Combining the energy consumption of BCs in each mode—including standby—into a 

single energy consumption metric through usage profiles, as described above, may allow DOE to 

establish such an integrated metric. 

Furthermore, DOE acknowledges that, in contrast to other consumer products 

rulemakings, where the number of distinct usage profiles is small, there are many BC end-use 

products with many different usage profiles. Thus, determining usage profiles representative of 

the wide variety of applications, as well as any future applications, could be difficult because of 

this wide variation. Nonetheless, usage profiles must be used—as PG&E agrees— to calculate 

the energy consumption associated with a potential standard in order to evaluate its impacts on 

energy savings. Therefore, regardless of their limitations, their incorporation in the standards 

analysis is unavoidable. 

Finally, AHAM commented that an integrated metric would allow manufacturers to 

adjust energy consumption in each mode to accommodate customer usage, citing previous DOE 

precedent in the case of clothes washers. (AHAM, No. 16 at p. 4) DOE agrees that such an 

integrated metric would give manufacturers some flexibility to improve the efficiency of their 

products in a cost-effective fashion by enabling them to focus on decreasing energy 

consumption in the modes where they will achieve the most efficiency gains. 

However, to best reflect actual usage would require setting separate standards for each 

application that uses BCs. Because of the complexity associated with the large number of 

applications, DOE has elected to group the usage profiles according to the product classes 

described earlier in section 2.3.2. While these aggregate usage profiles may not be an exact 

match for every application in the product class, they incorporate some of the features of each, 

and are more representative than PG&E’s proposal not to use usage profiles at all. 

The test procedure that DOE ultimately adopts would likely require energy consumption 

measurements in each mode as presented in the agency’s test procedure proposal. See 75 FR 

16958. These modal metrics would then be multiplied by the time spent in each mode, as 

specified by the above-described average usage profiles. These metrics would be contained in the 

standards section of the Code of Federal Regulations (CFR), similar to those that apply to 

dishwashers. See 10 CFR 430.23(c). 

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2.3.3.4 BC Technology Options 

Since most consumer BCs contain an AC/DC power conversion stage, similar to that 

found in an external power supply, all of the technology options discussed above in section 

2.3.3.2 also apply to BCs. The technology options used to decrease EPS no-load power will 

impact energy consumption of BCs in no-battery and maintenance modes (and off mode, if 

applicable), while those used to increase EPS conversion efficiency will impact energy 

consumption in active and maintenance modes. 

Additional technology options specific to BCs that DOE presented in the framework 

document included: 

Termination 

Elimination/Limitation of Maintenance Current 

Elimination of No-Battery Current 

Phase Control to Limit Input Power 

Several interested parties commented on these technology options. Micro Power 

Electronics noted the difficulty of implementing an AC power disconnect in a multi-bay or 

multi-port BC (i.e., one that charges several batteries independently). Such a disconnect—a 

potential way to eliminate no-battery current—would be difficult to implement because the 

charge controller must remain powered to detect when a battery is inserted into the charge bay. 

(MPE, No. 5 at p. 1) While DOE agrees that disconnecting the BC from the AC line may be 

more complicated in a multi-port charger, it is still a viable technology option, and is including it 

in the technology assessment. 

PG&E noted that the ability of the BC to detect a full battery and subsequently reduce 

current is a key way to reduce BC energy consumption. (PG&E, No. 13 at p. 10; PG&E, Pub. 

Mtg. Tr., No. 14 at p. 53 and 303) Whereas in the previous comment disconnection of the 

charger from the AC line is a technology option that decreases no-battery power, this comment 

pertains to maintenance mode. When the battery is fully charged, and the BC enters maintenance 

mode, BCs that terminate reduce the output current to the battery and thereby the input power to 

the charger. Without termination, this excess power is given off as heat in the battery. 

Termination is still a viable technology option, and DOE will evaluate it in the technology 

assessment. 

PG&E suggested that DOE consider a capacitive reactance circuit as a replacement for 

line-frequency transformers in slow chargers. (PG&E, No. 20 at p. 6; Pub. PG&E, Mtg. Tr., No. 

14 at p. 304) All BCs that connect to mains must convert higher-voltage AC mains power to 

lower-voltage DC power, because batteries only accept DC power. Whereas conventional power 

converters use a transformer to lower the voltage, a capacitive reactance circuit is another, 

potentially more efficient way to convert to a lower voltage. 

However, capacitive reactance circuits cannot be used in all applications because they are 

typically low-current and take multiple hours to charge a battery. Test results of a highly efficient 

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capacitive reactance charger submitted by PG&E reveal maintenance mode power of 0.1 watts 

and no-battery mode power of 0 watts. However, the initial charge mode power for a 7.1 watthour battery was 0.3 watts. Even if the battery charging system were 100 percent efficient, it 

would take approximately 24 hours to charge the battery, and in reality the test was run for 

96 hours (i.e., 4 days) to ensure a full charge. 

Furthermore, because it does not use a transformer, the capacitive reactance circuit does 

not provide galvanic isolation between input and output, meaning that the output of the circuit 

and any other electrical components connected to the output (e.g., battery terminals) must be out 

of reach of the user to prevent shock. Use of this circuit would also require adequate fireproofing 

of the end-use product if the battery is integral, as in the case of cordless telephones or handheld 

vacuum cleaners. 

Because the longer charging times and requirements to fireproof the end-use product 

enclosure, capacitive reactance circuits may have ―adverse impacts on product utility,‖ which is 

one of the criteria used in the screening analysis. Detailed discussion of this technology option 

and its applicability to each product class can therefore be found in chapter 4. 

PG&E presented a further list of technology options for decreasing the energy 

consumption of battery chargers: 

Improve power supply efficiency 

Reduce power supply no-load power 

Maintenance by periodic topping-off charge 

Switched-mode charge controller 

Automatic battery-connected on-off switch 

Improved electronic/magnetic components beyond the power supply 

Lower charging current or higher voltage (PG&E, No. 13 at p. 10) 

DOE included the above technology options in the technology assessment (see chapter 3). The 

final option suggested by PG&E—lowering charging current or increasing voltage—was 

screened out on the grounds that it would negatively impact consumer utility as it would require 

product redesign, with potentially detrimental results (see chapter 4). 

2.4 SCREENING ANALYSIS 

This section of the preliminary TSD focuses on comments from interested parties 

pertaining to the screening analysis as well as technology options that were screened out due to 

their failure to comply with one or more of the four screening criteria. Those technology options 

that were not screened out are discussed in chapter 4. After DOE identified the technologies in 

the technology assessment that could potentially improve the energy efficiency of BCs and EPSs, 

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DOE conducted the screening analysis. The purpose of the screening analysis is to evaluate the 

technology options that improve the efficiency of equipment to determine which options to 

consider further and which options to screen out. DOE consults with industry, technical experts, 

and other interested parties in developing a list of design options. DOE then applies the 

following set of screening criteria to determine which design options are unsuitable for further 

consideration in the rulemaking (10 CFR Part 430, subpart C, appendix A at 4(a)(4) and 5(b)): 

Technological Feasibility - DOE will consider technologies incorporated in commercial 

equipment or in working prototypes to be technologically feasible. 

Practicability to Manufacture, Install, and Service - If mass production of a technology 

in commercial equipment and reliable installation and servicing of the technology could 

be achieved on the scale necessary to serve the relevant market at the time of the 

compliance date of the standard, then DOE will consider that technology practicable to 

manufacture, install, and service. 

Adverse Impacts on Equipment Utility or Equipment Availability - If DOE determines a 

technology to have a significant adverse impact on the utility of the equipment to 

significant subgroups of consumers, or to result in the unavailability of any covered 

equipment type with performance characteristics (including reliability), features, sizes, 

capacities, and volumes that are substantially the same as equipment generally available 

in the United States at the time, it will not further consider this technology. 

Adverse Impacts on Health or Safety - If DOE determines that a technology will have 

significant adverse impacts on health or safety, it will not further consider this 

technology. 

For a complete discussion of the screening analysis, refer to chapter 4. 

2.4.1 Technology Options Screened Out 

PG&E commented that switched mode power supplies can power all non-medical 

consumer applications and should not be screened out. (PG&E, No. 20 at p. 8) In its comment, 

PG&E was alluding to the concern that switched-mode power supplies can have more electrical 

noise than linear-regulated power supplies. This noise can be transmitted to nearby circuits either 

through direct connections (through data lines, for example) or transmitted through the air (with 

power cables acting as antennas). However, technology advances for switched-mode power 

supplies have greatly reduced electrical noise issues, which would enable switched-mode power 

supplies to replace linear-regulated power supplies. At this time, DOE is unaware of cases 

where linear-regulated power supplies are the only technology option. In light of these advances, 

DOE did not screen out switched-mode power supplies or any other EPS technology option. 

AHAM stated that an energy conservation standard should not impact the safety of a 

product, particularly those products used in wet environments. (AHAM, Pub. Mtg. Tr., No. 14 at 

p. 43) DOE agrees that energy conservation standards should not impact the safety of a consumer 

product, which is one of the criteria DOE uses when evaluating technology options in its 

screening analysis. However, as mentioned earlier, any power conversion technology that 

providing galvanic isolation should be able to meet the safety requirements of BCs used in wet 

environments. Additionally, cleanliness, another concern is addressed in the screening analysis in 

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chapter 4 through the application of the ―adverse impacts on product utility‖ criterion. See supra, 

section 2.3.2.3. 

Similarly, the safety criterion was also used to screen out the capacitive reactance 

technology option, which involves the use of a capacitor to provide voltage transformation 

without galvanic isolation. 

In summary, DOE screened out the following BC technology options: 

Non-inductive chargers for use in wet environments 

Capacitive reactance 

Lowering charging current or increasing battery voltage 

2.5 ENGINEERING ANALYSIS 

In the engineering analysis (detailed in chapter 5), DOE develops a relationship between 

the manufacturer selling price (MSP) and increases in BC and EPS efficiency. The efficiency 

values range from that of a typical BC or EPS sold today (i.e., the baseline) to the maximum 

technologically feasible efficiency level. At each efficiency level examined, DOE determines the 

consequent MSP, a relationship referred to as a cost-efficiency curve. 

Below, DOE presents cost-efficiency curves for BCs and Class A EPSs. For non-Class A 

EPSs, DOE explains how it will develop cost efficiency curves based on the Class A EPS 

analysis and the non-Class A determination analysis. 

2.5.1 Approaches to Conducting the Engineering Analysis 

DOE structured its engineering analysis around two methodologies: (1) test and 

teardowns, which involves testing products for efficiency and determining cost from a detailed 

bill of materials derived from tear-downs and (2) the efficiency-level approach, whereby 

manufacturers provide and explain their costs of achieving increases in energy efficiency at 

discrete levels of efficiency. 

Interested parties expressed concern with the validity of the BC data obtained from 

manufacturer interviews in the efficiency-level approach. PG&E. commented that manufacturer 

interviews may provide incorrect costs as many manufacturers of battery-powered products 

subcontract the manufacturing of the BC and may not be familiar with the design details and 

costs. (PG&E, No. 20 at p. 12) PG&E. are correct in noting that BCs are typically purchased by 

the end-use product manufacturer or original equipment manufacturer (OEM) from an external 

supplier as a completed subassembly. Nonetheless, these manufacturers exercise strict control 

over the specification and design of the BCs, and are knowledgeable regarding their cost and 

achievable efficiencies. Furthermore, DOE supplemented the efficiency information obtained 

from manufacturers with teardowns conducted on BCs currently in the market. 

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PG&E noted that there are inexpensive products with very efficient BCs and expressed 

its belief that BC technology must, in turn, be inexpensive. (PG&E, Pub. Mtg. Tr., No. 14 at 

p. 58) DOE acknowledges PG&E’s comment that some applications with BCs are inexpensive 

and that their components are likely to be similarly inexpensive. Nonetheless, DOE is using the 

testing and teardown method to calculate costs for all BCs, which will more directly demonstrate 

the BCs’ costs. When analyzing the cost of each CSL—whether based on existing or theoretical 

designs—DOE differentiates the cost of the BC or EPS from the cost of the associated end-use 

product. 

2.5.2 Engineering Analysis for Class A External Power Supplies 

2.5.2.1 Class A EPS Representative Product Classes and Representative Units 

As discussed earlier in section 2.3.2.4, DOE divided Class A EPSs into four product 

classes for the preliminary analysis, following an examination of EPS technologies in the market 

and approaches used in other energy-efficiency programs. There were no comments from 

interested parties regarding Class A EPS product classes. 

Further examination of EPS units in the market led to the selection of one of the four 

product classes for further analysis as the representative product class. This class collectively 

constitutes the majority of EPS shipments and national energy consumption. DOE analyzed this 

class through testing, teardowns, and interviews with manufacturers. By focusing the analysis on 

the representative product class, DOE can provide the most accurate standards analysis for the 

applications that have the largest impact on users (due to high shipments, high per-unit energy 

consumption, or both) or that have the largest impact on the nation (due to high shipmentweighted energy consumption). Table 2.8 presents representative product class A1 in the context 

of the EPS product classes presented in Table 2.2. 

Table 2.8 Class A EPS Representative Product Class and Scaled Product Classes 

Basic Voltage Output Low Voltage Output * 

AC-DC Conversion A1 (representative) A2 (scaled) 

AC-AC Conversion A3 (scaled) A4 (scaled) 

* Low voltage output EPSs have nameplate output voltage less than six volts and nameplate output current greater 

than or equal to 550 milliamps. All other EPSs are basic voltage output. 

DOE subsequently focused its analysis on four representative units within the 

representative product class (A1), presented in Table 2.9. Because results from the analysis of 

these representative units would later be extended to additional EPSs, they were selected from 

high-volume and/or high-energy-consumption applications that use EPSs that are typical across 

EPSs in product class A1. Interested parties did not comment on the selection of representative 

units for analysis. Chapter 5 presents the test results used by DOE in its analysis. 

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Table 2.9 Class A EPS Representative Units 

Representative 

Unit 

Nameplate Output Power 

[watts] 

Nameplate Output Voltage 

[volts] 

Example 

Application 

1 2.5 5 Mobile phone 

2 18 12 Modem 

3 60 15 Laptop Computer 

4 120 19 Laptop Computer 

2.5.2.2 Class A EPS Candidate Standard Levels Analyzed for Product Class A1 

In its engineering analysis for Class A EPSs, DOE examined the impacts on cost of 

improving the efficiency of each of the representative units to evaluate the impact of potential 

energy efficiency standards. DOE performed this analysis by evaluating test results and 

manufacturer data, indicating possible steps to increase the efficiency of currently-available 

EPSs. To reflect these general steps in improving efficiency, DOE created several candidate 

standard levels (CSLs), as sets of equations, which represent increasingly stringent standards 

with higher-numbered CSLs. These CSLs are summarized for each representative unit in Table 

2.10, expressed in terms of average efficiency in active mode and power consumption in no-load 

mode. 

Table 2.10 Summary of Class A EPS Candidate Standard Levels of Efficiency 

Number Reference Basis 

CSL 0 EISA 2007 EISA 2007 equations for efficiency and no-load power 

CSL 1 

ENERGY STAR 

2.0 

ENERGY STAR 2.0 equations for efficiency and no-load 

power 

CSL 2 Intermediate Curve fit to data points 

CSL 3 Best in Market Curve fit to data points 

CSL 4 Max Tech Curve fit to data points 

CSLs are generally based on (1) other voluntary specifications or mandatory standards 

that cause manufacturers to develop products at particular efficiency levels; (2) the most efficient 

products available in the market; and (3) the maximum technologically feasible (―max tech‖) 

level.e 

DOE considered the current DOE standard level as the baseline CSL. EPCA, as amended 

by EISA 2007, determines EPS minimum efficiency and maximum no-load power consumption 

as a function of nameplate output power, shown in Table 2.11 and Table 2.12 , respectively. For 

this analysis, the baseline efficiency level, CSL 0, for each representative unit is the EISA level 

at the corresponding nameplate output power. 

e The ―max-tech‖ level represents the most efficient design that is commercialized or has been demonstrated in a 

prototype with materials or technologies available today. ―Max tech‖ is not constrained by economic justification 

apart from the requirement that there be more than one unique way to achieve it, per the discussion in 2.5.2.2. It is 

typically the most expensive design option considered in the engineering analysis. 

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Table 2.11 Baseline (CSL 0) EISA 2007 Active-Mode Efficiency for Product Class A1 

Nameplate Output Active Mode Required Efficiency 

(decimal equivalent of a percentage) 

<1 Watt 0.5 times the nameplate output 

1 to not more than 51 Watts The sum of 0.09 times the natural logarithm 

of the nameplate output and 0.5 

>51 Watts 0.85 

Table 2.12 EISA 2007 Standard Equation for Maximum No-Load Mode Power 

Consumption 

Nameplate Output Maximum Consumption 

Not more than 250 Watts 0.500 watts 

ASAP and PG&E asked DOE to include the ENERGY STAR EPS Version 2.0 as a CSL. 

(ASAP, Pub. Mtg. Tr., No. 14 at p. 40; PG&E, Pub. Mtg. Tr., No. 14 at p. 63) To that end when 

creating CSL 1, DOE considered the ENERGY STAR 2.0 specification. Similar to EISA, the 

ENERGY STAR 2.0 level is a function of nameplate output power, shown in 

Table 2.13 and Table 2.14. In addition to output power, ENERGY STAR 2.0 also considers the 

type of output power (DC or AC) and the output voltage. DOE chose CSL 1 to be the same as 

the ENERGY STAR 2.0 level for AC-DC basic output voltage EPSsf. DOE chose the divisions 

in the CSL 1 equations to be consistent with the divisions between the ENERGY STAR 2.0 

equations. The two sets of equations do not correspond exactly, however. Specifically, the 

divisions between the EISA equations are at 1 watt and 51 watts (shown in Table 2.11), but the 

divisions between the ENERGY STAR equations are at 1 watt, 49 watts, and 50 watts (shown in 

Table 2.13 and Table 2.14). 

Table 2.13 ENERGY STAR 2.0 Equation for Minimum Active-Mode Efficiency for Basic 

Output Voltage EPSs 

Nameplate Output Power (Pno) Minimum Average Efficiency in Active Mode 

(expressed as a decimal) 

0 to ≤ 1 watt ≥ 0.480 * Pno + 0.140 

> 1 to ≤ 49 watts ≥ [0.0626 * ln (Pno)] + 0.622 

> 49 watts ≥ 0.870 

f ENERGY STAR documents use the term ―standard voltage.‖ Because the word ―standard‖ is a term of art within 

DOE documents, DOE instead uses the term ―basic voltage‖ to reduce possible confusion. 

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Table 2.14 ENERGY STAR 2.0 Standard Equation for No-Load Mode Power 

Consumption 

Nameplate Output Power (Pno) Maximum Power in No-Load 

Ac-Dc EPS 

0 to ≤ 50 watt ≤ 0.300 watts 

> 50 watts ≤ 0.500 watts 

DOE created CSL 2 to be an intermediate level between the Energy Star (CSL 1) and best 

in market (CSL 3) levels. The specific combination of no-load power consumption and average 

efficiency for CSL 2 was chosen to optimize the tradeoff between cost and efficiency between 

CSL 1 and CSL 3. DOE evaluated each representative unit individually and developed sets of 

efficiency and no-load power pairings between CSL 1 and CSL 3. Using these data, DOE 

estimated their resultant unit energy consumptions (UECs) (see chapter 7 for details on 

calculating UECs) and compared the UECs against their associated MSPs, which were calculated 

from the aggregation of manufacturer MSP data (see chapter 5 for details on MSP aggregation). 

Subsequently, the final efficiency and no-load pairing used to characterize CSL 2 was selected 

by examining which of the prospective pairings had the highest weighted-average savings in the 

LCC analysis. 

DOE then used the CSL 2 pairings for the four representative units to create equations for 

average efficiency and no-load power by curve-fitting the efficiency characteristics for CSL 2 

(see chapter 5 for details on curve fits). For both the average efficiency and no-load power CSL 

equations, DOE used equations similar to those for CSL 1, involving linear and logarithmic 

terms in the nameplate output power. DOE chose the divisions at 1 watt, 49 watts, and 50 watts 

in the CSL 2 equations to ensure consistency with the nameplate output power divisions between 

the equations for CSL 1. 

Table 2.15 CSL 2 Intermediate Active-Mode Efficiency for Product Class A1 

Nameplate Output Power Minimum Average Efficiency in Active Mode 

(expressed as a decimal) 

0 to ≤ 1 watt 0.49 * Pout + 0.15 

> 1 to ≤ 49 watts 0.0701 * ln(Pout) - 0.0011 * Pout +0.647 

> 49 watts 0.870 

Table 2.16 CSL 2 Intermediate No-Load Mode Power Consumption for Product Class A1 

Nameplate Output Power Maximum Power in No-Load 

0 to ≤ 50watt ≤ 0.200 watts 

> 50 watts ≤ 0.230 watts 

CSL 3 reflects the most efficient product in the market (―best in market‖ or BIM), which 

DOE identified using test results of popular products identified in a market survey, models 

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identified in the ENERGY STAR 2.0 databaseg, and units available through EPS distributor 

websites. CSL 3 corresponds to the combination of average efficiency and no-load power 

consumption of the most efficient EPS units that DOE tested. For those units, DOE created the 

equations for average efficiency and no-load power using curve fits of the test results data among 

the four representative units (see chapter 5 for details on curve fits). For both the average 

efficiency and no-load power CSL equations, DOE used equations similar to those for CSL 1, 

involving linear and logarithmic terms in the nameplate output power. DOE chose the divisions 

at 1 watt, 49 watts, and 50 watts in the CSL 3 equations so that they were consistent with the 

nameplate output power divisions between the equations for CSL 1. 

Table 2.17 CSL 3 Best in Market Active-Mode Efficiency for Product Class A1 

Nameplate Output Power Minimum Average Efficiency in Active Mode 

(expressed as a decimal) 

0 to ≤ 1 watt 0.5 * Pout + 0.16 

> 1 to ≤ 49 watts 0.071 * ln(Pout) - 0.0014 * Pout +0.67 

> 49 watts 0.880 

Table 2.18 CSL 3 Best in Market No-Load Mode Power Consumption for Product Class A1 

Nameplate Output Power Maximum Power in No-Load 

0 to ≤ 50watt 0.100 

> 50 watts 0.210 

Finally, DOE determined CSL 4, the maximum technologically feasible (―max-tech‖) 

efficiency level, as required by section 325(o) of EPCA. (42 U.S.C. § 6295(o)). Earthjustice 

commented that DOE cannot legally ignore the evaluation of BC or EPS technologies considered 

to be proprietary or prototypes when developing the max tech CSL. (Earthjustice, No. 18, at p. 1) 

The agency notes that in determining whether standards would meet the statutorily-mandated 

criteria of being economically feasible, the agency must examine the competitive impacts of its 

choice of standards. By selecting a path that would force regulated entities to adopt a single, 

proprietary technology as the only feasible means of satisfying the standard, DOE would run 

afoul of its obligations under 42 U.S.C. § 6295(o) to consider the potential for lessened 

competition. The selection of such a path would not be likely to withstand the required scrutiny 

from the U.S. Department of Justice provided under the statute. (See 42 U.S.C. 

6295(o)(2)(B)(i)(I) through (VII)) 

To determine the max tech CSL, DOE interviewed manufacturers of EPSs, manufacturers 

of integrated circuits for EPSs, and manufacturer of applications that use EPSs. All of the 

manufacturers interviewed indicated how EPSs could achieve efficiencies higher than currently 

exist in the market and at what cost, Chapter 5 details this information. The accuracy of this 

information was independently verified by subject matter experts (SMEs) consulted by DOE. 

The SMEs believed that the data was reasonable, except for the max-tech value for the 2.5W 

g Taken in September 2009 from the ENERGY STAR 2.0 database at 

http://www.energystar.gov/index.cfm?fuseaction=find_a_product.showProductGroup&pgw_code=ACD 

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EPSs. The SMEs believe that those EPSs may be able to achieve a max tech efficiency of 80% 

rather than the 74.0% efficiency derived from manufacturers. The aggregated responses from 

manufacturers to that assertion are discussed in chapter 5. Because the 80% efficiency figure 

from SMEs had no corresponding cost data, DOE used a max-tech efficiency value of 74.0% to 

characterize CSL 4, because DOE had corresponding cost data at that efficiency level. 

DOE created the CSL 4 equations for average efficiency and no-load power using curvefits of the aggregated manufacturer data (see chapter 5 for details on curve fits). DOE created the 

equation for no-load power based on a curve fit of the no-load power among the four 

representative units. For both the average efficiency and no-load power CSL equations, DOE 

used equations similar to those for CSL 1, involving linear and logarithmic terms in the 

nameplate output power. DOE chose the divisions at 1 watt, 49 watts, and 50 watts in the CSL 4 

equations so that they were consistent with the nameplate output power divisions between the 

equations for CSL 1. 

Table 2.19 CSL 4 Max Tech Active-Mode Efficiency for Product Class A1 

Nameplate Output Power Minimum Average Efficiency in Active Mode 

(expressed as a decimal) 

0 to ≤ 1 watt 0.52* Pout + 0.17 

> 1 to ≤ 49 watts 0.079 * ln(Pout) - 0.0014 * Pout +0.67 

> 49 watts 0.910 

Table 2.20 CSL 4 Max Tech No-Load Mode Power Consumption for Product Class A1 

Nameplate Output Power Maximum Power in No-Load 

0 to ≤ 50watt 0.062 

> 50 watts 0.165 

2.5.2.3 Class A EPS Teardown Analysis 

For each representative unit, DOE analyzed the cost and efficiency of three EPS units 

that it purchased to characterize the baseline efficiency (CSL 0), Energy Star (CSL 1), and best 

in market (CSL 3) (except for the 120-watt representative unit; for that, DOE purchased two test 

units). To ensure that the results were comparable between units, DOE defined specific criteria 

for the representative unit for nameplate output power, nameplate output voltage, and output 

cord length. All of the EPS test units were chosen so that their specifications were close to or the 

same as the representative unit specifications. For the EPSs that differed slightly, DOE scaled 

their test results as specified in chapter 5. DOE then obtained an estimate of the costs for each of 

these EPS test units. 

Because detailed EPS component costs at large volumes are unavailable on the 

commercial market, DOE contracted iSuppli Corp., an industry expert in costs of consumer 

electronics, to tear down and estimate the materials cost for select units. iSuppli provided DOE 

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Production Cost Non-Production Cost

Direct

Labor

Direct

Materials Overhead Selling General &Administrative R&D Interest Profit

Full Cost of Product [$]

with the cost for all parts listed in the bill of materials (BOM cost). DOE used that information, 

together with the labor costs of assembly, the factory overhead costs, and markup costs to 

determine the manufacturer’s selling price (MSP), as shown in Figure 2.1. These cost estimates 

also account for the typical number of units produced by the manufacturer as well as the 

manufacturer’s location. 

Figure 2.1 Full Cost of Product: Breakdown of Production and Non-Production Costs 

2.5.2.4 Class A EPS Manufacturer Interviews 

In 2009 and 2010, on behalf of DOE, Navigant Consulting, Inc. (Navigant Consulting) 

interviewed manufacturers of EPSs, integrated circuits for EPSs, and applications that use EPSs 

to obtain data on EPS efficiencies and the costs associated with achieving those efficiencies. At 

the request of some manufacturers, Navigant Consulting entered into non-disclosure agreements 

whereby it can present to DOE general information about the EPS market and technology, but no 

confidential data specific to any individual manufacturer. These interviews enabled Navigant 

Consulting to obtain general information about the EPS market and technology to conduct the 

analysis without attributing any particular data to an individual manufacturer. DOE continues to 

seek input from interested parties regarding all aspects of the rulemaking, in particular cost and 

efficiency data. 

2.5.2.5 Class A EPS Scaling Relationships 

DOE developed scaling relationships that it used both to analyze representative unit data 

and to scale CSLs from product class A1 to other product classes. In general, the scaling methods 

for representative unit data were detailed whereas the scaling methods for CSLs were simpler. 

For the representative unit data DOE adopted the more detailed approach because the detailed 

methods provide enhanced accuracy, which was paramount, as it was the basis for later analyses, 

including the LCC and NIA. For the CSL equations, DOE adopted the simpler approach so that 

stakeholders could more easily evaluate the CSLs. As noted in the executive summary, DOE is 

seeking stakeholder comment on these approaches and may develop more detailed CSL 

equations in response to stakeholder comment. 

For the purposes of the preliminary analysis, DOE developed CSL equations that have 

the general form Y=a×ln(Pout) + b×Pout+c, for each of the nameplate output power segments, 

where Y indicates the efficiency or no load-power requirement; Pout indicates the nameplate 

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output power; and a, b, and c indicate the specific parameters defined in the respective CSLs. As 

explained in chapter 5, DOE has determined that output cord length and output voltage also have 

an effect on efficiency. Thus, DOE could have included terms in the CSL equations for output 

cord length and output voltage but doing so would have resulted in much more complicated 

equations that would have minimally enhanced accuracy. DOE accounts for differences in output 

voltage through different product classes, but does not account for differences in output cord 

length. For the NOPR, DOE intends to maintain the equations in this form, which is based on 

output power exclusively, unless interested parties prompt DOE to change this approach. 

Wherever possible, DOE selected test units that had the same characteristics as the 

representative units. Similarly, it sought data from manufacturers at the representative unit 

values. However, in some cases, test units and manufacturers’ data were slightly different from 

the representative unit specifications. In addition, the teardown and manufacturer cost data had to 

be normalized such that the costs included the same assumptions. For those cases DOE 

developed detailed scaling relationships so that the data would be most applicable to the 

representative unit analysis. 

Specifically, the Class A EPS engineering analysis characterizes the cost-efficiency 

relationship using average efficiency in active mode, power consumption in no-load mode and 

MSP. DOE did not develop scaling relationships for no-load mode power consumption because 

it is minimally affected by EPS representative unit characteristics. DOE considered developing a 

scaling relationship for cost by production volume. Specifically, for the representative units, 

DOE and iSuppli developed estimate production volumes that were on the order of 

approximately 1,000,000 units shipped per year. iSuppli indicated that prices did not change 

appreciably over that range; thus. scaling by production volume is not necessary. 

For the efficiency and MSP characteristics, DOE developed the following scaling 

relationships, detailed in chapter 5: 

Efficiency by nameplate output power. DOE scaled efficiency by output power 

using the EISA 2007 standard and ENERGY STAR 2.0 specification, which 

follow the market trend of increasing efficiency with increasing output power. 

Efficiency by nameplate output voltage. For EPSs of a given nameplate output 

power, lower nameplate output voltage results in higher current-associated losses 

and lower efficiency. DOE analyzed units with the same nameplate output power 

and different nameplate output voltages to characterize this relationship. DOE 

also evaluated a voltage scaling approach based on ENERGY STAR 2.0, for lowvoltage units. 

Efficiency by output cord length. Longer output cords provide consumers with the 

added utility of being able to operate the product farther from mains. Longer 

output cords also have higher losses and are more expensive. DOE analyzed 

output cords to characterize this relationship. 

Cost by nameplate output power. EPSs with higher nameplate output powers 

provide consumers with the added utility of being able to provide power to more 

power-demanding products. EPSs with higher nameplate output power also have 

more and larger components and, consequently, cost more. 

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Cost by output cord length. Longer output cords are more expensive. DOE 

analyzed output cords to characterize this scaling relationship. 

Markups. Test and manufacturer data costs at different points in the value chain 

represent different stages in the sale of an EPS. DOE characterized these markups 

in order to compare costs at the same stage in the value chain, namely MSP. 

Though in many cases the data did not require applying all of the scaling steps, all the 

scaling steps are nonetheless illustrated in the scaling section of chapter 5, in the order that they 

would be applied. 

2.5.2.6 Class A EPS Relationships Between Cost and Efficiency 

Because DOE used two methods to conduct the engineering analysis (the test and 

teardown data and aggregated manufacturer data methods), it generated two distinct outputs— 

one from each method—for each representative unit. 

For the test and teardowns analysis, DOE combined the scaled efficiency test results with 

the MSP for the three EPS test units used to characterize the baseline efficiency level, CSL 1, 

and CSL 3. The test and teardown analysis method does not include values for CSL 4 because, 

by definition, maximum technologically feasible units are typically not available for purchase. 

For the manufacturer interview analysis, DOE presented manufacturers with CSL 0, 

CSL 1, and CSL 3 as developed in the testing and teardown analysis. DOE asked manufacturers 

to develop their own estimate for CSL 4, max tech. For each of these CSLs, the manufacturers 

detailed the changes they would make to the EPS’ design and the associated costs. To maintain 

confidentiality, the manufacturers’ data was aggregated. 

In summary, for each representative unit, the manufacturer data for cost versus efficiency 

and cost versus no-load power data showed a trend of increasing MSPs with higher CSLs, 

meaning that it costs more to manufacture more efficient EPSs. On the other hand, the testing 

and teardown curves did not show a clear cost-efficiency relationship. In fact, in many cases, the 

CSL 3, best in market unit was the cheapest, and the CSL 0 unit was the most expensive. For all 

four representative units, the cost decreased from CSL 1 to CSL 3. 

DOE believes that, although it rigorously normalized the test unit data, there may be 

factors that affect cost which were not normalized. For example, as detailed in chapter 5, 

manufacturers indicate that reliability is another factor that greatly impacts EPS cost and that it is 

difficult to determine an EPS’s reliability without access to its specification sheet. Consequently, 

DOE believes the testing and teardown results to be inconclusive. Therefore, DOE plans to 

evaluate only the manufacturer data in its UEC, LCC, and NIA analyses for Class A EPSs. For 

the three representative units whose testing- and teardown-based cost-efficiency curves have 

CSL 3 as the least expensive CSL, the LCC for CSL 3 would be positive. For the NOPR, DOE 

intends to conduct another round of testing and teardowns for Class A EPSs that attempts to 

control for additional factors. In particular, DOE intends to attempt to control the data for 

reliability by selecting EPSs with similar end-use applications of similar quality. 

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2.5.2.7 CSLs for Class A EPS Product Classes Not Directly Analyzed (A2, A3, and 

A4) 

DOE identified and selected basic voltage AC/DC EPSs as the representative product 

class on which to concentrate its analytical effort. DOE chose this representative product class 

primarily due to its high market volumes and its ability to characterize the EPS market. DOE 

followed a two-step process to scale the CSLs from the representative units to product classes. 

First, DOE scaled from the four representative units with specific nameplate output power values 

to create a function that addresses all nameplate output power values in the AC-DC basic voltage 

EPS product class. DOE based this extrapolation on existing relationships defined by the EISA 

2007 standard for EPSs and the ENERGY STAR 2.0 specification for EPSs. Both the standard 

and specification use an equation to establish a correlation between an EPS’s nameplate output 

power and its efficiency. 

Next, DOE used the representative unit data and the CSL equations from product class 

A1 to create equations for the other three Class A EPS product classes. Because of similarities 

between Class A EPSs, DOE only needed to create two sets of additional equations to apply to 

the three non-analyzed product classes: a set of low-voltage efficiency equations and a set of 

AC/AC no-load power equations. Low-voltage EPSs (product classes A2 and A4) tend to have 

lower efficiencies than basic voltage EPSs (product classes A1 and A3), as explained in detail in 

chapter 5. In addition, DOE believes that AC/AC EPSs (product classes A3 and A4) tend to have 

higher no-load power consumption than AC/DC EPSs (product classes A1 and A2) because the 

ENERGY STAR 2.0 specification for no-load power is less stringent for AC/AC EPSs and 

because AC/AC EPSs do not have overhead circuitry to allow them to reduce power 

consumption in no-load mode, as discussed in section 2.3.2.2. Therefore, DOE applied the new 

equations to product classes A2, A3, and A4 according to how they related to A1, as shown in 

Table 2.8. 

Table 2.21 presents the low-voltage efficiency CSLs (VLOW), and Table 2.22 presents the 

AC/AC no-load power CSLs (PNL_AC). Both the low-voltage efficiency and AC/AC no-load 

power CSLs were created by scaling based on the CSLs from product class A1 and ENERGY 

STAR 2.0, which has the corresponding four-product class structure. See chapter 5 for more 

details on how DOE created the low-voltage efficiency and AC/AC no-load power CSLs. 

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Table 2.21 Active-Mode Efficiency CSLs for Low-Voltage EPSs (Product Classes A2 and 

A4) 

CSL Nameplate Output Power (Pno) Minimum Average Efficiency in Active Mode 

(expressed as a decimal) 

CSL 0 Identical to Basic Voltage CSL 0 Identical to Basic Voltage CSL 0 

CSL 1 

0 to ≤ 1 watt ≥ 0.497 × Pout + 0.067 

> 1 to ≤ 49 watts ≥ 0.075 × ln (Pout) + 0.561 

> 49 watts ≥ 0.860 

CSL 2 

0 to ≤ 1 watt ≥ 0.507 × Pout + 0.077 

> 1 to ≤ 49 watts ≥ 0.0825 × ln (Pout) - 0.0011 × Pout + 0.586 

> 49 watts ≥ 0.860 

CSL 3 

0 to ≤ 1 watt ≥ 0.517 × Pout + 0.087 

> 1 to ≤ 49 watts ≥ 0.0834 × ln (Pout) - 0.0014 × Pout + 0.609 

> 49 watts ≥ 0.870 

CSL 4 

0 to ≤ 1 watt ≥ 0.537 × Pout + 0.097 

> 1 to ≤ 49 watts ≥ 0.0914 × ln (Pout) - 0.0014 × Pout + 0.609 

> 49 watts ≥ 0.900 

Table 2.22 No-load Power CSLs for AC/AC EPSs (Product Classes A3 and A4) 

CSL Nameplate Output Power (Pno) Maximum Power in No-Load 

Ac-Ac EPS 

CSL 0 0 to ≤ 250watt ≤ 0.500 watts 

CSL 1 0 to ≤ 250watt ≤ 0.500 watts 

CSL 2 0 to ≤ 250watt ≤ 0.230 watts 

CSL 3 0 to ≤ 250watt ≤ 0.210 watts 

CSL 4 0 to ≤ 250watt ≤ 0.165 watts 

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2.5.3 Engineering Analysis for Non-Class A EPSs 

DOE developed its non-Class A EPS engineering analysis using a combination of 

approaches. In particular, DOE used the approach from its non-Class A EPS determination 

analysis and the Class A EPS analysis developed for this preliminary analysis. DOE used this 

approach for multiple-voltage and high-power EPSs because DOE developed the analysis using 

the same methods of testing and teardowns and manufacturer interviews as used for Class A 

EPSs in this preliminary analysis so the determination analysis is consistent with the current 

analytical approach. DOE notes that interested parties did not question this approach when 

commenting on the draft determination analysis that DOE had prepared. Similarly, DOE based 

its analysis for medical and MADB EPSs on the approach contained in the preliminary analysis 

for Class A EPSs because DOE is currently unaware of any technical limitations for medical and 

MADB EPSs to achieve the same efficiencies at the same costs as Class A EPSs. DOE also notes 

that interested parties raised no questions regarding this approach, except in the context of 

MADB wall adapters equipped with charge control. However, the presence of charge control 

indicates that an MADB wall adapter is not an EPS and, therefore, would not be within the scope 

of this rulemaking. 

2.5.3.1 Non-Class A EPS Representative Product Classes and Representative Units 

In this section DOE presents its selection of non-Class A EPS representative product 

classes and representative units based on the non-Class A EPS product classes presented in 

chapter 3. As noted previously, DOE based the non-Class A EPS product classes on the product 

classes from the non-Class A EPS determination analysis as well as the product classes 

developed in this preliminary analysis for Class A EPSs. 

Representative Product Classes and Units for Multiple-Voltage EPSs. DOE chose to 

treat both multiple-voltage EPS product classes as representative because there are significant 

differences between the two classes as shown in Table 2.23. As explained in detail in the 

determination analysis, representative product class X1 consists mainly of EPSs for imaging 

equipment. These multiple-voltage EPS have similar nameplate output power ratings for each 

output voltage. In contrast, EPSs in product class X2 are for video game applications and 

typically have one output that provides the majority of the output power. Because a single 

application constitutes the majority of shipments in each representative product class, DOE 

decided to use those applications as representative units as shown in Table 2.24. 

Table 2.23 Multiple Voltage EPS Representative Product Classes 

Nameplate Output Power Product Class 

< 100 watts 

≥ 100 watts 

X1 (representative 

X2 (representative) 

Table 2.24 Multiple-Voltage EPS Representative Units 

Nameplate Output 

Power [W] 

Nameplate Output 

Voltage [V] 

Second Nameplate 

Output Voltage [V] 

Example Application 

40 

203 

16 

5 

32 

12 

Multi-Function Device 

Video Game 

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Representative Product Classes and Units for High-Power EPSs. DOE chose to treat 

the high-power EPS product class as representative because it is the only product class (shown in 

Table 2.25). As explained in detail in the determination analysis, representative product class H1 

consists mainly of EPSs for ham radios. Because a single application constitutes the majority of 

shipments in the representative product class, DOE decided to use that application to define the 

attributes of the representative unit shown in Table 2.26. 

Table 2.25 High Power EPS Representative Product Classes 

Nameplate Output Power Product Class 

> 250 watts H1 (representative) 

Table 2.26 High-Power EPS Representative Units 

Nameplate Output Power [W] Nameplate Output Voltage [V] Example Application 

345 13.8 Amateur Radio 

Representative Product Classes and Units for Medical EPSs. DOE chose to treat only 

medical EPS product class M1 as representative because there are significant similarities 

between the product classes shown in Table 2.27. Specifically, the medical EPS product classes 

have the same product class structure as the Class A EPS product classes, as explained in chapter 

3. To that end, DOE applied the same structure for the medical EPS representative product 

classes and representative units (shown in Table 2.28). 

DOE took this approach because it is consistent with the approach for medical EPSs in 

the determination analysis. Specifically, the determination analysis presented representative 

product classes and units for medical EPSs based on Class A EPSs. Interested parties did not 

question the validity of this approach in the determination analysis. Since publishing the 

determination analysis, DOE has enhanced its understanding of Class A EPSs through additional 

testing, teardowns, and manufacturer interviews. Consequently, the representative product 

classes and units presented in Table 2.27 and Table 2.28 are consistent with the Class A EPS 

analysis in chapter 5. 

Table 2.27 Proposed Medical EPS Representative Product Classes 

Basic Voltage Output Low Voltage Output* 

AC-DC Conversion 

AC-AC Conversion 

M1 (representative) 

M3 (scaled) 

M2 (scaled) 

M4 (scaled) 

* Low voltage output EPSs have nameplate output voltage less than six volts and nameplate output current greater 

than or equal to 550 milliamps. All other EPSs are basic voltage output. 

Table 2.28 Possible Medical EPS Representative Units 

Representative 

Unit 

Nameplate Output 

Power 

[watts] 

Nameplate Output 

Voltage 

[volts] 

Example 

Application 

1 

2 

3 

4 

2.5 

18 

60 

120 

5 

12 

15 

19 

Blood Pressure Monitor 

Medical Nebulizer 

Sleep Apnea Machine 

Portable Oxygen Concentrator 

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Representative Product Classes and Units for MADB EPSs. DOE chose to treat only 

MADB EPS product class B1 as representative because there are significant similarities between 

the product classes as shown in Table 2.29. Specifically, the MADB EPS product classes have 

the same product class structure as the Class A EPS product classes, as explained in chapter 3. 

To that end, DOE applied the same structure for the MADB EPS representative product classes 

and representative units (shown in Table 2.30). Since DOE can apply all Class A EPS analysis to 

MADB EPSs, it intends to include a 120-watt representative unit, if necessary. However, Table 

2.30 reflects that DOE has not identified an associated application for this unit. As noted in the 

executive summary, DOE is seeking stakeholder comment on any applications that use a 120­

watt MADB EPS and whether to analyze this unit if it cannot identify any associated 

applications. 

DOE took this approach because it is consistent with the approach for MADB EPSs in 

the determination analysis. Specifically, in the determination analysis DOE created 

representative product classes and units for MADB EPSs based on Class A EPSs. Interested 

parties did not question the validity of this approach in the determination analysis. As with 

medical EPSs, since publishing the determination analysis, DOE has further enhanced its 

understanding of Class A EPSs through additional testing, teardowns, and manufacturer 

interviews. Consequently, the representative product classes and units presented in Table 2.29 

and Table 2.30 are consistent with the Class A EPS analysis in chapter 5. 

Table 2.29 Proposed MADB EPS Representative Product Classes 

Basic Voltage Output Low Voltage Output* 

AC-DC Conversion 

AC-AC Conversion 

B1 (representative) 

B3 (scaled) 

B2 (scaled) 

B4 (scaled) 

* Low voltage output EPSs have nameplate output voltage less than six volts and nameplate output current greater 

than or equal to 550 milliamps. All other EPSs are basic voltage output. 

Table 2.30 Possible MADB EPS Representative Units 

Representative 

Unit 

Nameplate Output 

Power 

[watts] 

Nameplate Output Voltage 

[volts] 

Example 

Application 

1 

2 

3 

4 

2.5 

18 

60 

120 

5 

12 

15 

19 

RC Toy 

DIY Power Tool 

Motorized Bicycle 

[none identified] 

2.5.3.2 Non-Class A EPS Candidate Standard Levels of Efficiency 

In this section, DOE presents its selection of CSLs for non-Class A EPSs and explains 

how it will develop the CSL equations in the NOPR. DOE based these levels using the CSLs 

from the determination analysis and the preliminary analysis for Class A EPSs. 

Candidate Standard Levels of Efficiency for Multiple-Voltage EPSs. As indicated 

earlier, DOE based its development of CSLs for multiple-voltage EPSs on those presented in the 

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non-Class A EPS determination analysis. DOE took this approach primarily because multiplevoltage EPSs are distinct from single-voltage EPSs in two ways. First, they share different 

underlying technologies, particularly, different overhead circuitry to control power flow to each 

output. This factor is significant because these circuit differences may result in a different range 

of efficiency levels, and possibly a max tech level that is lower than the single-voltage EPS level, 

for the same output power. Second, there are currently no established standard levels in the 

multiple-voltage EPS market. Consequently, DOE structured the CSLs for multiple-voltage EPSs 

based on products available in the market and the theoretical maximum technologically feasible 

level described by manufacturers as shown in Table 2.31. 

Table 2.31 Multiple-Voltage EPS Candidate Standard Levels of Efficiency 

Number Reference Basis 

CSL 0 

CSL 1 

CSL 2 

CSL 3 

Market Bottom 

Mid Market 

Best in Market 

Max Tech 

Least efficient units in the market 

Efficiency in the middle of the market 

Curve fit to most efficient test unit data points 

Curve fit to manufacturer max tech data points 

In the determination analysis, DOE based its efficiency values for each CSL on test and 

manufacturer data. For the NOPR, DOE may gather more data for multiple-voltage EPSs with 

which to develop specific efficiency values for each CSL. In contrast to Class A EPSs whose 

minimum average efficiency and maximum no-load power consumption requirements are 

functions of nameplate output power, DOE plans to use a single efficiency metric for each CSL. 

DOE considers this approach to be appropriate because although product classes X1 and X2 span 

a range of nameplate output powers, DOE is aware of only one significant application in each 

product class, requiring only one efficiency value. Further, because DOE is currently unaware of 

other significant applications, DOE is unable to characterize other products in the market to 

develop an equation similar to the CSL equation used for single-voltage EPSs. 

Candidate Standard Levels of Efficiency for High-Power EPSs. DOE based its 

development of CSLs for high-power EPSs on those presented in the non-Class A EPS 

determination analysis. Specifically, high-power EPSs are distinct from other types of EPSs for 

two reasons: their underlying technology is different and there are no established standard levels 

in the high-power EPS market. Consequently, DOE structured the CSLs for high-power EPSs 

based on products available in the market and the theoretical maximum technologically feasible 

level described by manufacturers, as shown in Table 2.32. 

Table 2.32 High-Power EPS Candidate Standard Levels of Efficiency 

Number Reference Basis 

CSL 0 

CSL 1 

CSL 2 

CSL 3 

Market Bottom 

Mid Market 

Best in Market 

Max Tech 

Least efficient units in the market 

Efficiency in the middle of the market 

Curve fit to most efficient test unit data points 

Curve fit to manufacturer max tech data points 

The determination analysis used efficiency values for each CSL on test data and 

manufacturer data. For the NOPR, DOE may gather more data for high-power EPSs with which 

to develop specific efficiency values for each CSL. In contrast to Class A EPSs whose minimum 

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average efficiency and maximum no-load power consumption requirements are functions of 

nameplate output power, DOE intends to have a single efficiency metric for each CSL. DOE 

believes this approach is appropriate because although product class H1 spans a range of 

nameplate output powers, it has only one significant application and therefore only needs one 

value. 

Candidate Standard Levels of Efficiency for Medical EPSs. DOE based its CSLs for 

medical EPSs using the levels developed for Class A EPSs (product class A1). DOE adopted 

this approach because medical EPSs share two key similarities. First, their underlying 

technology is similar, which indicates that they can achieve the same efficiencies. Second, 

because medical EPSs and Class A EPSs similar technologies, the established standards for Class 

A EPSs can be applied to medical EPSs as well. 

In spite of these similarities, however, there are also two key differences between medical 

EPSs and Class A EPSs. First, medical EPSs are exempt from the Class A energy efficiency 

requirements set out by EISA 2007. In light of the fact that medical EPSs are not covered by the 

Class A standards, DOE currently believes that medical EPSs may be less efficient than their 

Class A EPS-counterparts, although DOE did not find any medical EPSs with efficiency levels 

less than the EISA level in the determination analysis. This possibility led DOE to the tentative 

view that there may be medical EPSs less efficient than EISA standards and ultimately 

influenced the agency’s range of potential CSLs from which to choose. Second, as noted in 

chapter 3, medical EPSs conform to additional safety requirements. These requirements make the 

absolute price of medical EPSs higher than Class A EPSs, but do not affect medical EPS 

efficiency or incremental cost. Consequently, DOE structured the CSLs for medical EPSs based 

on the Class A EPS CSLs and set the baseline CSL 0 to the least efficient Class A EPS unit used 

to characterize the medical EPS market as shown in Table 2.33. All other CSL equations come 

directly from the Class A EPS analysis. For example, the baseline CSL 0 for Class A EPSs is 

CSL 1 for medical EPSs. 

Table 2.33 Medical EPS Candidate Standard Levels of Efficiency 

Number Reference Basis 

CSL 0 

CSL 1 

CSL 2 

CSL 3 

CSL 4 

CSL 5 

Market Bottom 

EISA 2007 

ENERGY STAR 2.0 

Intermediate 

Best in Market 

Max Tech 

Least efficient units in the market 

EISA 2007 equations for efficiency and no-load power 

ENERGY STAR 2.0 equations for efficiency and no-load 

power 

Curve fit to data points 

Curve fit to most efficient test unit data points 

Curve fit to manufacturer max tech data points 

In the determination analysis DOE based its efficiency values for each CSL on existing 

levels of efficiency in the market, test data, and manufacturer data. For the NOPR, DOE is 

considering gathering more data for medical EPSs with which to develop specific efficiency 

values for the baseline CSL 0. This approach would enable DOE to characterize the benefits of 

higher standards to consumers purchasing EPSs with efficiencies below EISA requirements. 

However, DOE believes that those consumers constitute a small and shrinking part of the market, 

based on information from manufacturer interviews. Therefore, DOE is also considering 

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accounting for the lowest part of the market in the ―EISA qualified‖ CSL as a simplifying 

alternative. Under this alternate approach, there would be no difference in treatment between 

Class A EPSs and medical EPSs in the engineering analysis. As noted in the executive summary, 

DOE is seeking stakeholder comment on which approach to use. 

Regardless of how DOE treats EPSs that are not covered by the EISA 2007-prescribed 

standards, DOE intends to apply data from Class A EPSs directly to medical EPSs for those 

CSLs that are common between the two products. For each CSL, DOE intends to have equations 

that are functions of nameplate output power similar to Class A EPSs. In particular, DOE intends 

to apply the Class A EPS equations directly to the corresponding medical EPS CSLs. In addition, 

to scale medical EPS CSL equations from product class M1 to the other product classes, DOE 

intends to use the Class A EPS methodology and results. DOE believes this approach is 

appropriate because of the similarity between medical EPSs and Class A EPSs. 

Candidate Standard Levels of Efficiency for MADB EPSs. DOE developed its CSLs for 

MADB EPSs using the CSLs for Class A EPSs (product class A1) presented in chapter 5. 

Specifically, MADB EPSs are similar to Class A EPSs in two ways: their underlying technology 

is similar, and there are established standard levels that can be applied to the MADB EPS 

market. However, there is one difference between MADB EPSs and Class A EPSs, which 

affected DOE’s choice of CSLs. Namely, MADB EPSs are not covered by the EISA 2007 

standards, which led DOE to believe that some MADB EPSs may be less efficient than Class A 

EPSs because they are not required to meet EISA standards. In contrast to medical EPSs, DOE 

believes that MADB EPSs do not conform to additional requirements, safety or otherwise. 

Consequently, DOE structured the CSLs for MADB EPSs based on the Class A EPS CSLs and 

set the baseline CSL 0 to the least efficient MADB EPS units in the market as shown in Table 

2.34. All other CSL equations come directly from the Class A EPS analysis. For example, the 

baseline CSL 0 for Class A EPSs is CSL 1 for MADB EPSs. 

Table 2.34 MADB EPS Candidate Standard Levels of Efficiency 

Number Reference Basis 

CSL 0 

CSL 1 

CSL 2 

CSL 3 

CSL 4 

CSL 5 

Market Bottom 

EISA 2007 

ENERGY STAR 2.0 

Intermediate 

Best in Market 

Max Tech 

Least efficient units in the market 

EISA 2007 equations for efficiency and no-load power 

ENERGY STAR 2.0 equations for efficiency and noload power 

Curve fit to data points 

Curve fit to most efficient test unit data points 

Curve fit to manufacturer max tech data points 

In the determination analysis DOE based its definitions of the efficiency values for each 

CSL on existing levels of efficiency in the market, test data and manufacturer data. For the 

NOPR, DOE is considering gathering more data for MADB EPSs with which to develop specific 

efficiency values for the baseline CSL 0. This would enable DOE to characterize the benefits of 

higher standards to consumers purchasing EPSs with efficiencies below EISA requirements. 

However, DOE believes that those consumers constitute a small and shrinking part of the market, 

based on information from manufacturer interviews. Therefore, DOE is also considering 

accounting for the lowest part of the market in the ―EISA qualified‖ CSL as a simplifying 

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alternative. Under this alternate approach, there would be no difference between Class A EPSs 

and MADB EPSs in the engineering analysis. As noted in the executive summary, DOE is 

seeking stakeholder comment on which approach to pursue. 

Regardless of how DOE treats EPSs that are not covered by the EISA 2007 standards, 

DOE intends to apply data from Class A EPSs directly to MADB EPSs for those CSLs that are 

common between the two products. For each CSL, DOE intends to have equations that are 

functions of nameplate output power similar to Class A EPSs. In particular, DOE intends to 

apply the Class A EPS equations directly to the corresponding MADB EPS CSLs. In addition, to 

scale MADB EPS CSL equations from product class M1 to the other product classes DOE 

intends to use the Class A EPS methodology and results. DOE believes this approach is 

appropriate because of the similarity between MADB EPSs and Class A EPSs. 

2.5.3.3 Developing Cost-Efficiency Results for non-Class A EPSs 

In this section DOE presents its methodology to develop cost-efficiency curves for nonClass A EPSs. DOE intends to develop cost-efficiency curves based on the data used to generate 

cost-efficiency curves in the determination analysis as well as the data used to generate costefficiency curves for Class A EPSs in this preliminary analysis. 

To develop the NOPR, DOE intends to use the same scaling and analysis techniques for 

both Class A EPSs and non-Class A EPSs. Thus, DOE intends to revise the data from the nonClass A EPS determination analysis for the NOPR. Specifically, in developing the Class A EPS 

engineering analysis in this preliminary analysis, DOE refined the scaling methodologies it used 

in the non-Class A EPS engineering analysis in the determination analysis. In addition, DOE 

evaluated EPSs based on the full costs of all materials, as opposed to the determination analysis, 

which evaluated EPSs based on the efficiency-related materials cost. DOE believes that its 

refined scaling methods have enhanced the robustness of the analysis, and that the full cost of an 

EPS is a more appropriate basis for evaluation because EPS components are interrelated. The 

following subsections explain how DOE plans to use data from the determination analysis; in all 

cases, DOE would apply the updated scaling and analysis techniques to the data. 

Cost-Efficiency Curves for Multiple-Voltage EPSs. DOE developed its cost-efficiency 

curves for multiple-voltage EPSs using data obtained by testing and tearing down EPSs and from 

manufacturer interviews. DOE intends to use a similar approach in the NOPR and believes that 

the cost-efficiency curves for multiple-voltage EPSs that it presented in the determination 

analysis are reasonably accurate because it used the same analytical methods as were used for 

Class A EPSs in this preliminary analysis. DOE also notes that it received no comments from 

interested parties pointing to flaws in its approach. Therefore, DOE intends to use that data (with 

updated scaling and analysis techniques) to develop the cost-efficiency curves in the NOPR for 

product classes X1 and X2. 

Cost-Efficiency Curves for High-Power EPSs. The determination analysis also 

presented cost-efficiency curves for high-power EPSs that relied on data obtained by testing and 

tearing down EPSs, as well as interviewing manufacturers. DOE intends to use a similar 

approach in the NOPR. Specifically, DOE believes that the cost-efficiency curves for high-power 

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EPSs that it presented are reasonably accurate because it used the same analytical methods as 

were used for Class A EPSs in this preliminary analysis. . DOE also received no comments 

pointing to flaws with the use of this approach. Therefore, DOE intends to use that data (with 

updated scaling and analysis techniques) to develop the cost-efficiency curves in the NOPR for 

product class B1. 

Cost-Efficiency Curves for Medical EPSs. To develop cost-efficiency curves for product 

class M1 for medical EPSs in the NOPR, DOE intends to apply the cost-efficiency curves for 

Class A EPSs because it believes medical EPSs to be technically equivalent to Class A EPSs 

other than that they conform to more stringent safety standards, which does not affect their 

incremental cost and therefore does not affect their cost-efficiency relationship. . In addition, 

DOE may conduct testing, teardowns, and manufacturer interviews to gather data on EPSs that 

are not covered by the EISA 2007-prescribed standards. 

Cost-Efficiency Curves for MADB EPSs. To develop cost-efficiency curves for product 

class B1 for MADB EPSs in the NOPR DOE intends to apply the cost-efficiency curves for 

Class A EPSs because it believes MADB EPSs to be technically equivalent to Class A EPSs such 

that they share the same cost-efficiency relationship. In addition, DOE will conduct testing, 

teardowns, and manufacturer interviews to gather data on EPSs with efficiencies less than the 

EISA standard. 

2.5.4 Engineering Analysis for Battery Chargers 

2.5.4.1 BC Representative Product Classes and Representative Units 

As discussed earlier in section 2.3.2, the preliminary analysis divides BCs into 10 product 

classes. DOE adopted this approach after analyzing comments from interested parties and 

examining market-available BC technologies. 

Further examination of BC units in the market led to a subset of the 10 product classes 

being selected for further analysis as the representative product classes. These classes were 

analyzed through testing, teardowns, and interviews with manufacturers. Collectively, the classes 

constitute the majority of BC shipments and national energy consumption. By focusing its 

analysis on the representative product classes, DOE can provide the most accurate standards 

analysis for the applications that have the largest impact on users (due to high shipments or high 

per-unit energy consumption) or that have the largest impact on the nation (due to high 

shipment-weighted energy consumption). Table 2.35 presents the representative product classes 

in the context of the BC product classes developed in chapter 3. 

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Table 2.35 BC Representative Product Classes 

Product 

Class 

Number Product Class 

Representative or Scaled Product 

Class 

AC 

In, 

DC 

Out 

< 

100 

Wh 

Inductive 

Connection 1 Low Energy, Inductive Representative 

<4 V 2 Low Energy, 

Low Voltage Representative 

4–10 V 3 Low Energy, 

Med. Voltage Scaled 

>10 V 4 Low Energy, 

High Voltage Representative 

100– 

3000 

Wh 

<20 V 5 Med. Energy, 

Low Voltage Representative 

≥20 V 6 Med. Energy, 

High Voltage Scaled 

> 3000 Wh 7 High Energy Representative 

DC In, 

DC Out 

<9 V Input 8 

Low Energy, 

Low Voltage 

DC Input 

Scaled 

≥9 V Input 9 

Low Energy, 

High Voltage 

DC Input 

Scaled 

AC In, 

AC Out 

AC Output 

from 

Battery 

10 Low Energy, 

AC Output Representative 

DOE subsequently focused its analysis on one representative unit, an idealized BC 

typical of those used for high-volume applications in a given representative product class. 

Because results from the analysis of these representative units would later be extended to 

additional BCs, they were selected from high-volume and/or high-energy-consumption 

applications that use batteries that are typical across BCs in the product class. 

For each representative product class, DOE then identified the most common battery 

voltage and energy combinations from a survey of popular battery-operated products in the 

market, taking into account the distribution of those BC characteristics by application. DOE then 

selected the BC characteristics of the representative units to correspond to the densest clusters of 

BC models. Interested parties did not comment on the selection of representative units for 

analysis, except for Delta-Q, which commented that DOE should consider testing its QuiQ 

charger because it is representative of the 1000 watt class of BCs. (Delta-Q, No. 15 at p. 1) 

DOE purchased and tested several BCs for golf cars with output power between 850 and 

1000 watts, intended for charging a 48 volt, 3750 watt-hour flooded lead-acid battery. This 

representative unit, and the other representative units, are presented in Table 2.36. 

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Table 2.36 The BC Representative Units for each Representative Product Class 

Product 

Class 

Number 

Rep. Unit 

Voltage 

V 

Rep. Unit 

Energy 

Wh 

Avg. Annual 

Production 

Volume 

K units 

AC 

In, 

DC 

Out 

< 100 

Wh 

Inductive 

Connection 1 3.6 1.5 500 

<4 V 2 3.6 3 480 

4–10 V 3 Scaled Product Class 

>10 V 4 10.8 20 640 

100– 

3000 

Wh 

<20 V 5 12 800 50 

≥20 V 6 Scaled Product Class 

> 3000 Wh 7 48 3,750 150 

DC In, 

DC Out 

<9 V Input 8 Scaled Product Class 

≥9 V Input 9 Scaled Product Class 

AC In, 

AC Out 

AC Output 

from Battery 10 12 70 1000 

2.5.4.2 BC Candidate Standard Levels Analyzed 

In its engineering analysis of BCs, DOE examined the cost impacts of improving the 

efficiency of each of the representative units presented in Table 2.36 to evaluate potential energy 

efficiency standards. DOE performed this analysis by evaluating the design options and 

corresponding costs necessary to increase the efficiency of currently-available BCs to each 

candidate standard level (CSL). 

CSLs are generally based on (1) design options associated with the specific units being 

analyzed; (2) other voluntary specifications or mandatory standards that cause manufacturers to 

develop products at particular efficiency levels; and (3) the maximum technologically feasible 

level.h For example, in the EPS case, DOE considered the current DOE standard level as the 

baseline CSL and the ENERGY STAR level as another, higher CSL (see section 2.5.2.2). 

Several interested parties commented on the CSLs that DOE should use for the BC 

preliminary analysis. PG&E commented that DOE should include CSLs that encompass design 

options that are not currently common in the marketplace. (PG&E, No. 20 at p. 12) Similarly, 

PG&E recommended that DOE look at a wide variety of efficiencies across different BCs. 

(PG&E, Pub. Mtg. Tr., No. 14 at p. 58) 

h The ―max-tech‖ level represents the most efficient design that is commercialized or has been demonstrated in a 

prototype with materials or technologies available today. ―Max tech‖ is not constrained by economic justification 

apart from the requirement that there be more than one unique way to achieve it, per the discussion in 2.5.2.2. It is 

typically the most expensive design option considered in the engineering analysis. 

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The max-tech CSL mentioned above is based on technologies that are typically only 

available in prototype form and not commercially available. Furthermore, DOE also intends to 

analyze the best-in-market level for the preliminary analysis. Because this level will be based on 

annual energy consumption of the most efficient commercially available BCs, DOE does not 

expect their design options to be common, as the majority of the market will have lower 

efficiency. DOE also intends to analyze these lower efficiency levels, including the least efficient 

BCs for each representative unit battery voltage and energy, satisfying PG&E’s request to 

evaluate a wide variety of BCs. 

CEC et al. requested that DOE analyze the efficiency standard for BCs that PG&E 

proposed to the State of California to adopt as part of its efficiency standards -- PG&E, in turn, 

asked that DOE adopt that proposed standard. (CEC et al., No. 19 at p. 1; PG&E, Pub. Mtg. Tr., 

No. 14 at p. 54) That standard, if adopted, would specify a specific 24-hour energy efficiency 

that is only dependent upon a battery charger’s rated battery energy. As explained above, the 

evaluation of BCs currently in the market underlies DOE’s engineering analysis except for the 

max-tech CSL, which cannot be met by any commercially available BCs and must be derived 

and evaluated through modeling and interviews with manufacturers. According to PG&E’s data, 

which were presented to DOE at the framework document public meeting, there are few BCs for 

batteries with energies above 10 watt-hours that can meet PG&E’s proposed standard. (PG&E 

No. 13 at pp. 7–9) 

Although DOE’s testing identified additional BCs in the market that could meet the 

proposed PG&E standards (including ones with battery energies greater than 10 watt-hours), the 

BCs’ energy consumption in each mode does not always fall near the PG&E proposed standards 

level, sometimes exceeding the standard by a wide margin. Therefore, a direct evaluation of the 

PG&E standards proposal may not always be possible, even though some of the best-in-market 

and all the max-tech units analyzed would meet the proposed standard. 

However, DOE intends to examine a variety of applications in the market. In addition to 

the baseline, best-in-market, and max-tech levels, DOE also analyzed BC units at an ―improved‖ 

level, where available. This level is not associated with any standard or guideline, but rather 

reflects the energy consumption achievable by units in the market through the application of 

some of the energy efficiency design options presented earlier (see section 2.3.3.4). 

These CSLs are summarized for each representative unit in Table 2.37 below, expressed 

in terms of annual energy consumption, calculated by summing the BC energy consumption in 

each mode, assuming a class-average usage profile. 

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Table 2.37 Candidate Standard Levels for the BC Representative Units 

# Efficiency Level 

Annual Energy Consumption by Representative Unit 

kWh 

Low 

Energy, 

Inductive 

Low 

Energy, 

Low 

Voltage 

Low 

Energy, 

High 

Voltage 

Med. 

Energy, 

Low 

Voltage 

High 

Energy 

Low 

Energy, 

AC 

Output 

1.5 Wh, 

3.6 V 

3 Wh, 

3.6 V 

20 Wh, 

10.8 V 

800 Wh, 

12 V 

3750 Wh, 

48 V 

70 Wh 

12 V 

0 Baseline 10.0 10.0 39.4 202.7 290.0 19.6 

1 Improved 7.0 6.0 10.5 159.6 250.0 6.4 

2 Best-in-Market 

Maximum 

3.5 1.2 6.1 100.0 200.0 4.0 

3 Technologically 

Feasible 

1.5 - - 75.0 150.0 1.5 

2.5.4.3 BC Teardown Analysis 

As mentioned in the discussion above, the CSLs used in the BC engineering analysis 

were based on the efficiencies of BCs available in the market. Following testing, the units 

corresponding to each commercially available CSL were disassembled to (1) evaluate the 

presence of energy efficient design options and (2) torn down to estimate material costs. The 

disassemblies were performed by one of DOE’s subject-matter experts and included an 

examination of the general design of the BC and an evaluation of the presence of any of the 

technology options discussed in chapter 3. 

After the BC units corresponding to the CSLs were evaluated, they were torn down by 

iSuppli, another DOE contractor. These teardowns were comparable to those conducted for EPSs 

and described in section 2.5.2.3, with the exception of BCs embedded inside complex consumer 

electronic applications such as camcorders and notebook computers. 

Because the BC constitutes a small portion of the circuitry of these products, DOE, 

through iSuppli (a firm specializing in consumer electronics costs), identified the subset of 

components in each product enclosure responsible for battery charging, including the battery, 

charge regulator, and any related power converters and voltage regulators. The function of the 

latter two subcircuits was split between the battery charger and other aspects of the application 

(e.g., powering the notebook computer in addition to charging its battery). Nonetheless, because 

of the crucial role played by these subcircuits in the battery charging process, their full cost was 

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included in the BC manufacturing cost estimate. Details regarding BC teardowns for the 

representative units are in chapter 5. 

2.5.4.4 BC Manufacturer Interviews 

Navigant Consulting, a DOE contractor, entered into non-disclosure agreements and 

interviewed representatives of several firms that manufacture battery-powered products or BCs 

for those products. Navigant Consulting aggregated the responses from these interviews and 

presented DOE with generalized responses free of any proprietary data for use in the analysis. 

During the course of each interview, interviewers asked the representatives to provide 

information about technology options for increasing the energy efficiency of BCs that ship with 

their products. Prior to each interview, each manufacturer received a Cost-Efficiency Estimation 

Survey (included as appendix 5C) to guide their responses. To ensure consistency between 

manufacturers, the survey specified the parameters of each BC representative unit under 

consideration. See Table 2.36. 

For each representative unit, the interviewers asked manufacturers to describe the 

technological improvements and associated costs necessary to meet each of the CSLs presented 

in section Table 2.37. These CSLs were presented in a disaggregated form (i.e., energy 

consumption by mode, rather than combined into a weighted annual energy consumption) to help 

the respondents. Finally, manufacturers were also encouraged to present data on BCs they were 

most familiar with, even if those did not perfectly match with the CSLs listed in Table 2.35. An 

aggregated summary of their responses, divided by representative unit, is presented in chapter 5. 

2.5.4.5 BC Cost Model 

Similar to EPSs, DOE gathered inputs on markups for BCs from manufacturer 

interviews. In particular, manufacturers were asked to provide typical markups (due to 

production and non-production costs, as well as profits) of BC suppliers, OEMs, and distributors 

and retailers. These markups were subsequently used to adjust the price of a BC at any point in 

the supply chain, whether that point was identified through manufacturer interviews or 

teardowns, to the manufacturer selling price (MSP), charged by the BC supplier to the OEM. 

In either case, the analysis focused on the cost of BC components directly related to 

efficiency—i.e., the electronics. The analysis excluded the cost of the packaging, output cord, 

and cosmetic touches. These may vary from product to product, and their costs depend greatly on 

the application and the degree of integration of the BC with the end-use product. The markups 

for each product class are presented in detail in chapter 5. 

2.5.4.6 BC Relationships between Cost and Efficiency 

DOE integrated the results of the BC teardown analysis with the information obtained 

during manufacturer interviews, including markups, to arrive at the relationship between cost and 

efficiency for the BC representative units. This cost of meeting each candidate standard level of 

efficiency is the main result of the engineering analysis and is used in both the life-cycle cost 

(LCC) and payback period (PBP) analysis and the national impacts analysis (NIA). 

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Following the publication of the framework document, Micro Power Electronics (MPE) 

noted that setting an efficiency standard above 80% could exclude the single-ended primary 

inductor converter (SEPIC) architecture, which is low cost. (MPE, No. 5 at p. 1) This comment 

highlights some of the issues considered during the engineering analysis, and one of its expected 

outcomes—that the cost of BCs is likely to increase for higher CSLs. The full engineering results 

for each representative unit, including the designs necessary to meet each CSL, are presented in 

chapter 5. 

2.5.4.7 BC Scaling from Representative Units to Product Classes 

Following the development of engineering results for the representative units, DOE must 

extend this analysis to all BCs that were not analyzed but covered by the standard. This task is 

twofold: (1) scaling the representative unit results to BCs that are also in the representative 

product class, but which differ in battery voltage and energy; and (2) scaling the representative 

unit results to BCs in product classes not explicitly analyzed. 

As mentioned in section 2.3.2.1, PG&E suggested that DOE mitigate boundary issues by 

using a continuous function when setting the standard. (PG&E, No. 20 at p. 7) Such a function 

would also be used to scale the engineering results from the representative units to other BCs not 

explicitly analyzed. 

However, developing the correct scaling relationships presents a challenge because of the 

wide variety of BC designs, each of which responds differently to changes in battery voltage and 

energy. For example, PG&E commented that DOE cannot use scaling relationships for AC-AC 

power supplies when developing scaling relationships for BCs that use switched-mode AC-DC 

power supplies. (PG&E, No. 20 at p. 13) Similarly, Delta-Q commented that DOE should not 

scale BC engineering analysis findings across large differences in output power, and should 

consider the applicability of new technologies on a case-by-case basis. (Delta-Q, No. 15 at p. 1) 

However, neither commenter provided a basis for their recommendations. 

In response to these comments, DOE used a hybrid approach to scaling in the preliminary 

analysis. When possible, DOE first attempted to use engineering relationships to scale the 

performance of BC designs at each CSL, dividing the problem by operational mode and BC 

stage (i.e., power supply, charge controller), such that the final energy consumption of a scaled 

unit was a function of the expected performance of each stage in each mode, weighted by the 

average time spent in each mode. 

In cases where this was not possible, DOE scaled the results based on test results of 

actual BCs available in the market. Overall, DOE attempted to minimize the effects of scaling 

BC performance by directly analyzing a number of representative units across a broad range of 

BC output power. 

For the preliminary analysis, DOE used the engineering-based method to obtain costefficiency results for the scaled product classes. By modeling the energy consumption of the 

representative units in situations typical of BCs in other classes (summarized in Table 2.38), 

DOE was able to estimate the cost and efficiency of meeting the CSLs as shown in Table 2.39. 

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DOE has not yet scaled the CSLs for each representative unit (and the scaled units in Table 2.38) 

to all the remaining BCs within each product class. 

Table 2.38 The BC Representative Units for each Representative and Scaled Product Class. 

Product 

Class 

Number 

Rep. Unit 

Voltage 

V 

Rep. Unit 

Energy 

Wh 

Avg. Annual 

Production 

Volume 

K units* 

AC 

In, 

DC 

Out 

< 100 

Wh 

Inductive 

Connection 1 3.6 1.5 500 

<4 V 2 3.6 3 480 

4–10 V 3 7.2 10 480 

>10 V 4 10.8 20 640 

100– 

3000 

Wh 

<20 V 5 12 800 50 

≥20 V 6 36 384 50 

> 3000 Wh 7 48 3,750 150 

DC In, 

DC Out 

<9 V Input 8 3.6 2 480 

≥9 V Input 9 3.6 5 480 

AC In, 

AC Out 

AC Output 

from Battery 10 12 70 1000 

* Note: The production volume for product classes 3, 8, 9 uses product class 2 data, and the production volume for 

product class 6 uses product class 5 data. 

Table 2.39 Candidate Standard Levels for the Scaled BC Representative Units. 

# Efficiency Level 

Annual Energy Consumption by Representative Unit 

kWh 

Low Energy, 

Medium 

Voltage 

10Wh, 7.2V 

Medium 

Energy, High 

Voltage 

384Wh, 36V 

Low Energy, 

Low Voltage 

DC Input 

2Wh, 3.6V 

Low Energy, 

High Voltage 

DC Input 

5Wh, 3.6V 

0 

1 

2 

3 

Baseline 

Improved 

Best-in-Market 

Maximum 

Technologically 

Feasible 

10.0 69.3 1.5 1.3 

5.4 41.9 0.9 0.8 

1.0 25.0 0.8 0.5 

- 18.0 - -

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2.6 MARKUPS TO DETERMINE PRODUCT PRICE 

DOE used markups to convert the manufacturer selling prices (MSPs) of BCs and EPSs, 

which were calculated in the engineering analysis, to consumer prices, which then were used in 

the life-cycle cost (LCC) and payback period (PBP) and national impact analyses. DOE 

calculates markups for baseline products (baseline markups) and for more efficient products 

(incremental markups). The incremental markup relates the change in the MSP of higherefficiency models (the incremental cost increase) to the change in the retailer or distributor sales 

price. 

DOE made the following key assumptions in calculating markups: 

The dominant path to market establishes the retail price and, thus, the composite markup 

for a product. 

The markups applied to end-use products that use BCs and EPSs are approximations of 

BC and EPS markups. 

The baseline markups that manufacturers and retailers apply to end-use products that use 

BCs and EPSs are equal to those companies’ average markups across their entire product 

lines. 

Expenses like labor and administrative costs remain fixed and need not be recovered in 

the incremental markup. Profits and other operating costs are assumed to be variable and 

to scale with the MSP. 

Markups can be derived from inspection of companies’ public financial filings. 

To determine which markups are applied to the MSP, DOE first modeled the distribution 

channels for BCs and EPSs. Research indicated that the most common path begins with BC/EPS 

manufacturers, progresses through end-use product manufacturers (OEMs), and ends with 

consumer product retailers or distributors (retailers), at which point a sales tax is applied and the 

BC or EPS is sold to consumers. DOE relied on publicly available corporate financial data to 

estimate individual product markups. 

Vivitar and Earthjustice commented that the increase in manufacturing costs from 

producing more efficient units is not always passed directly to consumers. Rather, some 

manufacturers may reduce markups to offset these increased costs. (Vivitar, Pub. Mtg. Tr., No. 

14 at p. 242; Earthjustice, No. 18 at p. 2) DOE recognizes that competition between 

manufacturers may pressure some to lower markups and absorb higher input costs. Thus, DOE 

maintained the practice employed in previous rulemakings of applying a lower markup to the 

incremental costs associated with more efficient products. 

2.7 ENERGY USE ANALYSIS 

The energy use analysis provides estimates of annual energy use for BCs and EPSs. To 

estimate EPS energy use DOE multiplied annual usage in each application state and operating 

mode (in hours per year) by the power estimates (in watts). For BCs, DOE multiplied annual 

usage in each operating mode (in hours per year or charges per year) by the power estimates (in 

watts) or energy per charge (in watt hours). DOE developed its power and energy estimates in 

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the engineering analysis. To determine annual usage, DOE examined how end users operate BCs 

and EPSs with the consumer products they power. 

DOE made the following key assumptions in calculating BC and EPS energy 

consumption: 

Energy consumption of an EPS or BC is defined as energy drawn from the source (e.g., 

mains) but not provided to the application (if an EPS) or battery (if a BC). 

Usage and power requirements of the BC or EPS depend on usage and power 

requirements of the application. 

The power requirements of applications (and, in the case of BCs, batteries) do not change 

over the period of analysis. 

Only one usage profile is assigned to each application, although DOE considered 

multiple user types in developing this profile for certain common applications. 

While the mix of applications may change over time, the usage profile for the BCs or 

EPSs in a product class as a whole remains fixed over time. 

These assumptions are explained below and in chapter 7. 

2.7.1 External Power Supply Usage and Energy Consumption 

For most electrical appliances, power consumption is determined by measuring the power 

an application draws from mains while performing its intended function(s). However, BCs and 

EPSs are power conversion devices, and their intended function is to deliver a portion of the 

power drawn from mains in one form to another application in another form. Therefore, the 

traditional method for calculating energy consumption is not appropriate for BCs and EPSs. 

Instead, energy consumption is determined by calculating the energy dissipated by the BC or 

EPS. 

An EPS’s active mode power requirements depend on how much power the application 

requires. Because the application has different operating states, the amount of power required 

from the EPS varies by state. In order to examine EPS power consumption in active mode, DOE 

determined the different operating states of the application and how much power (expressed as a 

percentage of nameplate output power) each ―application state‖ requires from the EPS. 

During the framework document public meeting, DOE requested comment on its 

assumption that most applications require 80 percent of the EPS’s nameplate output power when 

in the highest energy consuming application state. PTI commented that this assumption is a 

reasonable estimate. (PTI, Pub. Mtg. Tr., No. 14 at p. 273) Subsequently, DOE tested four of the 

most common EPS applications and determined that a lower default value may be more accurate. 

DOE uses in its preliminary analysis a value of 60 percent of nameplate output power for those 

applications for which data are lacking. DOE plans to test additional applications in the future 

and may adjust this assumed value as appropriate. 

EPS active mode power can easily be estimated for application states that demand 25 

percent of nameplate output power or greater by using the average active-mode efficiency from 

the test procedure to calculate the difference between the power drawn from mains and the 

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power provided to the application. However, EPSs are not as efficient when providing less than 

25 percent of nameplate output power. Thus, DOE interpolated between EPS power at 25 percent 

of nameplate output power and EPS power in no-load mode to more accurately estimate EPS 

power at low loads. PG&E voiced support for this methodology, with PG&E noting that 

―Interpolation of a line between no load and 25% may not be accurate for all switch mode power 

supplies.‖ PG&E added that it believed that interpolation of the input power through this load 

range is probably satisfactory. (PG&E, Pub. Mtg. Tr., No. 14 at p. 272; PG&E, No. 20 at p. 10) 

DOE combined time and power estimates in active mode with time and power estimates 

in no-load (standby) mode to calculate unit energy consumption in all EPS modes. Only EPSs 

with on/off switches can operate in off mode. Because DOE did not identify any EPSs with 

on/off switches, DOE did not attribute any time to this mode. 

PTI commented in response to the NOPD that it agreed with the EPS usage profile DOE 

used in its determination analysis for wall adapters involved in charging detachable batteries for 

power tools. (PTI, EERE-2009-BT-DET-0005 No. 5 at p. 2) DOE carried forward that same EPS 

usage profile into the preliminary analysis. 

2.7.2 Battery Charger Usage and Energy Consumption 

During the framework document public meeting, DOE suggested that it would create 

usage profiles based on 24-hour charge cycles and use the 24-hour energy consumption 

measurement from the test procedure to represent active mode energy consumption. DOE 

received support from PG&E for basing usage profiles on 24-hour charge cycles. (PG&E, No. 20 

at p. 9; PG&E, Pub. Mtg. Tr., No. 14 at p. 257) However, DOE determined that building usage 

profiles around 24-hour charge cycles is unrealistic for frequently used applications such as MP3 

players that are not left to charge for an entire day. Therefore, based on a suggestion by PG&E, 

DOE isolated charge energy over the 24-hour charge cycle and examined BC usage in terms of 

the number of complete charge equivalents and time spent in each mode annually. (PG&E, Pub. 

Mtg. Tr., No. 14 at p. 257) DOE combined charges and charge energy with time and power 

estimates for maintenance, no-battery (standby), and off modes to calculate unit energy 

consumption in all BC modes. 

DOE received input from three parties on BC usage profiles. PG&E provided usage 

profiles for fourteen BC applications during the framework document comment period and later 

submitted usage profiles with charge frequency for additional applications. (PG&E, No. 20 at p. 

13) Philips described how usage profiles for personal care products differ, which allowed DOE 

to develop separate usage profiles for beard trimmers and electric toothbrushes. (Philips, No. 22 

at p. 3) PTI commented that BC usage profiles should account for multiple user types. (PTI, Pub. 

Mtg. Tr., No. 14 at p. 259) Where data were available, DOE examined usage profiles for 

different user types and developed a single usage profile to best represent overall usage for each 

BC application. 

2.8 LIFE-CYCLE COST AND PAYBACK PERIOD ANALYSIS 

The LCC and PBP analysis is used to determine the economic impact of potential 

standards on end users. The effects of standards on individual end users include changes in 

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operating expenses (usually lower) and changes in total installed cost (usually higher). DOE 

analyzed the net effect of these changes for battery chargers (BC) and external power supplies 

(EPS). DOE first calculated the changes in end-users’ LCCs likely to result from various 

candidate standard levels compared to a base case (no new standards). The LCC calculation 

considers total installed cost (which includes manufacturer selling price, sales taxes, distribution 

chain markups, and installation cost), operating expenses (energy, repair, and maintenance 

costs), product lifetime, and discount rate. DOE performed the LCC analysis from the 

perspective of users of BCs and EPSs. 

DOE also analyzed the effect of changes in operating expenses and installed costs by 

calculating the PBP of potential standards relative to a base case. The PBP estimates the amount 

of time it would take the end user to recover the higher purchase expense of more energy 

efficient products through lower operating costs. Similar to the LCC, the PBP is based on the 

total installed cost and operating expenses. However, unlike the LCC, only the first year's 

operating expenses are considered in the PBP calculation. Because the PBP does not account for 

changes in operating expense over time or the time value of money, it is also referred to as a 

simple payback period. For more detail on the LCC and PBP analyses, see chapter 8 of the 

preliminary TSD. 

2.8.1 Approach 

DOE conducted the LCC and PBP analysis by modeling both the uncertainty and 

variability in the inputs using Monte Carlo simulation methods and probability distributions. 

(See appendix 8B of the preliminary TSD for a detailed explanation of Monte Carlo simulation 

and the use of probability distributions). DOE implemented Monte Carlo simulation and 

probability distributions by using Microsoft Excel spreadsheets combined with Crystal Ball®, a 

commercially available add-in program. 

DOE defined the use characteristics of BCs and EPSs by characterizing a set of end-use 

applications (―applications‖) for each representative unit and representative product class 

(―representative unit‖). These applications determine the profiles of the BCs and EPSs, such as 

energy usage, product lifetime, and pricing markups. 

DOE used data from the Energy Information Administration (EIA) on electricity prices 

for different customer classes and electrical utilities to establish the variability in energy pricing. 

Due to the large range of applications and product use characteristics considered in the LCC and 

PBP analysis, the range of annual energy use is broad. Although the annual energy use and/or 

energy pricing are known for any particular application, the variability across all applications 

contributes to the range of LCCs and PBPs calculated for any particular standard level. 

In each Monte Carlo simulation, a typical energy use profile is selected from a 

distribution of energy consumption profiles for the different applications associated with each 

representative unit. The selected profile for the representative unit is used to estimate the BC or 

EPS energy use. Further information on these application profiles can be found in appendix 8C 

of this preliminary analysis. 

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2.8.2 Life-Cycle Cost Inputs 

For each efficiency level analyzed, the LCC analysis requires input data for the total 

installed cost of the BC or EPS, the operating cost, and the discount rate. Table 2.40 summarizes 

the inputs DOE used to calculate the total installed cost and operating cost of various energy 

efficiency levels for BCs and EPSs. A more detailed discussion of the inputs follows. For more 

information on data sources and assumptions used, see chapter 8 of the preliminary TSD. 

Table 2.40 Summary of Inputs Used in the Life-Cycle Cost Analysis 

Input Characterization 

Manufacturer Selling Price Varies with BC and EPS 

Markups Varies with BC and EPS 

Sales Tax Varies by census region 

Installation Cost No installation cost associated with BCs or EPSs 

Unit Energy Consumption Varies with BC and EPS by efficiency level 

Energy Prices Vary by sector and census region 

Energy Price Trends Vary with price forecast scenario 

Repair and Maintenance Costs No repair or maintenance costs associated with BCs or EPSs 

Lifetime Mean lifetime for a BC or EPS varies with application 

Discount Rate Varies with sector 

2.8.2.1 End-User Product Price 

BCs and EPSs are unique appliances because they are always used in conjunction with 

other products of interest. Since most BCs and EPSs are packaged with particular products, 

consumers usually do not buy the BC or EPS directly. Instead, consumers typically obtain an 

EPS for a video game system when buying the video game system itself. Although the LCC and 

PBP analysis uses the consumer purchase prices of BCs and EPSs, in reality those prices are 

most often a ―hidden‖ portion of the prices that consumers pay for the products of interest. 

DOE determined the baseline and incremental markups for each point in the BC and EPS 

supply chain, as well as the sales tax, in the markups analysis (chapter 6 of the preliminary TSD). 

The types and amounts of markups differ between applications categorized by the representative 

units. For this reason, DOE calculated markups independently for each application considered. A 

listing of total markups by application as used in the LCC and PBP analyses can be found in 

appendix 8C to this preliminary analysis. 

2.8.2.2 Distribution Markups and Sales Taxes 

DOE determined the baseline and incremental markups for each point in the BC and EPS 

supply chain, as well as the sales tax, in the markups analysis (chapter 6 of the preliminary TSD). 

The types and amounts of markups differ between applications categorized by the representative 

units. For this reason, DOE calculated markups independently for each application considered. A 

listing of total markups by application as used in the LCC and PBP analyses can be found in 

appendix 8C to this preliminary analysis. 

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2.8.2.3 Installation Costs 

DOE found no relevant installation costs associated with BCs or EPSs. This is because 

installation typically entails a consumer simply unpacking the BC or EPS from the box it was 

sold in and connecting the device to mains power and its associated product or battery. Because 

the cost of this ―installation‖ (which may be considered temporary, as intermittently used devices 

might be unplugged for storage) is not quantifiable in dollar terms, DOE considers the 

installation cost to be zero. For this reason, DOE categorizes the total installed cost of BCs and 

EPSs as the final product price for these units. 

2.8.2.4 Energy Prices and Energy Price Trend 

DOE developed nationally representative distributions of electricity prices for different 

customer categories (residential and commercial) from 2008 EIA Form 861 data. At the 

framework document public meeting, Vivitar commented that a recent news article noted that 

many users charge their products while at work, and suggested that DOE consider sectors other 

than the residential sector for its electricity price analyses. (Vivitar, Pub. Mtg. Tr., No. 14 at p. 

349) DOE agrees with this comment, and has expanded its sector analysis to include the 

commercial sector for the life-cycle cost analyses. At this time, DOE does not have sufficient 

data to analyze how residential consumers use their BC or EPS in a commercial setting, or vice 

versa. The average electricity prices for each sector (in 2009$) are 11.5 cents for the residential 

sector, and 10.1 cents for the commercial sector. 

PG&E commented that DOE should use marginal electricity prices rather than average 

prices because they most closely represent the actual changes on a consumers’ energy bill. 

(PG&E, Pub. Mtg. Tr., No. 14 at pp. 358, 356, 374; PG&E, No. 20 at p. 10) DOE notes that 

average electricity prices are typically used for rulemakings on products that do not contain a 

great degree of seasonality or time sensitivity, whereas marginal electricity prices are typically 

used for rulemakings on products that do. This is because the marginal energy prices can help 

capture insight into energy prices during peak loading hours for products that are used differently 

at different periods of time. DOE has found no evidence that this is the case for BCs and EPSs, 

which operate without much seasonality or time sensitivity. In cases such as these, the energy 

costs from marginal electricity rates are oftentimes close to that of average prices. In light of this 

fact and the complexity of incorporating marginal electricity rates, DOE decided to use average 

electricity prices for its BC and EPS analyses. However, DOE may consider a consumer 

subgroup with steeply inclined block rates during the NOPR stage of the rulemaking, as 

described in section 2.11. 

Similarly, PG&E commented that DOE should factor time of use into its electricity prices 

because California is moving toward critical-peak pricing, and other parts of the country are 

looking into a time-of-use system as well. (PG&E, Pub. Mtg. Tr., No. 14 at p. 360) DOE has not 

found any data to suggest that time-of-use factors have a significant impact on BCs or EPSs. 

Additionally, DOE notes that only a portion of the nation’s utilities charge customers based on a 

time-of-use plan. Due to the fragmented nature of the utilities industry, it would be difficult to 

draw conclusions based on the limited time-of-use data available. As a result, DOE did not 

consider time-of-use when calculating electricity prices. 

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During the public meeting, PG&E inquired if DOE planned to use energy prices from a 

nationally weighted average by population or a simple average. (PG&E, Pub. Mtg. Tr., No. 14 at 

p. 357) Consistent with other rulemakings, DOE utilized a national utility-consumer weighted 

average for determining energy prices. Additionally, DOE examined consumer-weighted 

electricity prices broken out at different regional levels for its Monte Carlo simulation analysis. 

DOE used recent price forecasts by EIA to estimate future trends in electricity prices in 

each sector. To arrive at prices in future years, DOE multiplied the average prices described in 

the preceding section by the forecast of annual average price changes in EIA’s ―Annual Energy 

Outlook (AEO) 2010 Early Release.‖ To estimate the trend after 2035, DOE followed past 

guidelines provided to the Federal Energy Management Program (FEMP) by EIA and used the 

average rate of change from 2025 to 2035 for electricity. 

During the public meeting, PG&E asked if DOE planned to conduct interviews with 

utilities to try to get information about future rate increases. (PG&E, Pub. Mtg. Tr., No. 14 at p. 

361) PG&E also commented that DOE should account for Renewable Energy Portfolio 

Standards (RPS) when calculating future energy prices. (PG&E, Pub. Mtg. Tr., No. 14 at p. 373) 

DOE decided to utilize the AEO for projecting energy price trends, as is the standard procedure, 

and the AEO already takes these two suggestions into account. The projections in the AEO 

consider a comprehensive review of utilities, and also consider the ramifications of the statelevel RPSs. 

DOE calculated the LCC and PBP using three separate projections from ―AEO 2010: 

Reference, Low Economic Growth, and High Economic Growth.‖ The AEO2010 Early Release 

was the most recent AEO available at the time of this preliminary analysis. This AEO2010 

contained only the reference-case economic growth projection, however. In order to develop 

high-economic-growth and low-economic-growth cases for the LCC and PBP analysis, DOE 

obtained the differences between the reference case and the high- and low-economic-growth 

cases in the March 2009 AEO2009, which includes all three cases. DOE then utilized these 

differences as scaling factors to generate high- and low-economic-growth cases based on the 

AEO2010 Early Release reference case. 

At the public meeting, PG&E commented that DOE should consider environmental 

impacts, such as cap and trade emissions limitations. (PG&E, Pub. Mtg. Tr., No. 14 at p. 358) In 

response to this comment, DOE also considered an electricity price projection sensitivity using a 

carbon cap and trade scenario developed in response to the Lieberman-Warner Climate Security 

Act of 2007. This sensitivity illustrates an elevated electricity price projection based on 

emissions regulations as outlined in the EIA’s S.2191 report accompanying the Act. 

2.8.2.5 Repair and Maintenance Costs 

BCs and EPSs are not usually repaired because they typically outlast the applications that 

they power, and the cost of repair would generally exceed the cost of a new replacement. DOE 

found no evidence that repair or maintenance costs would increase with higher BC or EPS 

energy efficiency. Thus, DOE did not include changes in repair and maintenance costs for BCs 

or EPSs that are more efficient than baseline products. 

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2.8.2.6 Lifetime 

DOE considers the lifetime of a BC or EPS to be from the moment it is purchased for end 

use up until the time when it is permanently retired from service. Because the typical BC or EPS 

is purchased for use with a single associated application, DOE assumes that it will remain in 

service for as long as the application does. Therefore, the lifetime of a given BC or EPS is 

directly tied to the useful life of the application it is associated with, and will not vary with 

increases in energy efficiency. In instances where the lifetime of the BC or EPS is not tied to the 

application, DOE will apply the lifetime of the BC or EPS rather than the application lifetime. A 

possible example may be the lifetime of a cell phone charger, as manufacturers move towards 

implementing a universal charger for cell phones. 

Each representative unit for BCs and EPSs contains several applications, and each 

application has its own, unique lifetime. In light of this, DOE sampled lifetimes from among the 

applications associated with each representative unit using their shipments for weighting. 

Accordingly, the lifetime distribution for each representative unit is based on the importance of 

each application to the representative unit, as determined by shipments. The lifetimes for these 

applications were taken from market data and industry interviews for the relevant applications, 

and are outlined in chapter 3 of the preliminary analysis. DOE’s application sampling 

methodology is covered in more detail in appendix 8C of this preliminary analysis. The 

summarized lifetime estimates for each representative unit are outlined in Table 2.41. 

Table 2.41 Market-Weighted Lifetimes for Representative Units 

Representative Unit Lifetime 

Yrs 

Class A External Power Supplies 

2.5 Watt Regular AC/DC 4.6 

18 Watt Regular AC/DC 4.4 

60 Watt Regular AC/DC 4.0 

120 Watt Regular AC/DC 3.3 

Battery Chargers 

Low Energy, Inductive 5.0 

Low Energy, Low Voltage 3.4 

Low Energy, High Voltage 4.2 

Medium Energy, Low Voltage 5.5 

High Energy 6.4 

Low Energy, AC Out 6.0 

2.8.2.7 Discount Rate 

The discount rate is the rate at which future expenditures are discounted to estimate their 

present value. DOE derived the discount rates separately for residential and commercial 

consumers. For residential consumers, DOE estimated the discount rate by looking across all 

possible debt or asset classes that might be used to purchase or operate BCs or EPSs. For the 

commercial consumers, DOE estimated the cost of capital for commercial companies by 

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examining both debt and equity capital and developing an appropriately weighted average of the 

cost to the company of equity and debt financing. For each end-use sector, DOE developed a 

distribution of discount rates from which the Monte Carlo simulations sample. Further detail on 

the discount rate calculations can be found in chapter 8 of the preliminary TSD. 

For the residential sector, DOE assembled a distribution of interest or return rates on all 

possible debt or asset classes that might be used to purchase BCs or EPSs. DOE estimated the 

average shares of the various debt and asset classes in the average U.S. household portfolio using 

the Federal Reserve Board’s ―Survey of Consumer Finances‖ (SCF) data for 1989, 1992, 1995, 

1998, 2001, 2004, and 2007. DOE used the mean share of each class across the seven survey 

years (18 years) as the basis for estimating household financing of BCs and EPSs. The weightedaverage discount rate for residential product owners is 5.6 percent. Further detail on the 

residential discount rate calculations can be found in appendix 8D of the preliminary TSD. 

For the commercial sector, DOE used a weighted average of the cost to the firm of equity 

and debt financing. DOE estimated the cost of equity financing using the Capital Asset Pricing 

Model (CAPM). The CAPM, among the most widely used models to estimate the cost of equity 

financing, assumes that the cost of equity is proportional to the amount of systematic risk 

associated with a firm. DOE estimated the cost of debt financing by adding a risk adjustment 

factor to the current yield on long-term corporate bonds (the risk-free rate). This procedure is 

used to estimate current and future company costs to obtain debt financing. 

By calculating interest rates for equity and debt financing, DOE was able to determine a 

distribution of discount rates for each class of potential owners using data from the Damodaran 

online investment survey.

i Each class of potential owners was then weighted by the number of 

total employees in that class, using comparative statistics from the U.S. Census Bureau. The 

weighted-average discount rate for commercial product owners is 7.0 percent. 

At the July 16, 2009, public meeting, PG&E asked if the low interest rates present in the 

current economy would artificially skew the discount rate for the consumer, and how DOE 

accounts for the value of money to a consumer in a recession. (PG&E, Pub. Mtg. Tr., No. 14 at 

p. 354) DOE does not believe that its discount rates are artificially skewed based on the current 

economic conditions because the rates are based on data spanning 20 to 30 years. Consistent with 

other rulemakings, DOE calculates the discount rate by analyzing multiple forms of debt and 

equity financing from 1989 through 2007 (the most current data), in addition to the opportunity 

cost of multiple asset classes and their returns over the time period of 1979 to 2009. This method 

of calculating a discount rate ensures that temporary disruptions in interest rates will not have a 

significant impact on the discount rate used during the analysis. 

2.8.2.8 Compliance Date of Standard 

The compliance date is the future date when a new standard becomes operative. DOE’s 

publication of a final rule in this standards rulemaking is scheduled for completion by July 2011. 

The compliance date for amended EPS standards is July 1, 2013. (42 U.S.C. 

6295(u)(3)(D)(i)(II)(bb)) The compliance date for BC standards is also July 1, 2013. DOE 

i The survey is available at http://pages.stern.nyu.edu/~adamodar. 

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calculated the LCCs for all consumers as if each would purchase a new product in the year of the 

compliance date (January 1, 2013). However, DOE based the cost of the product on the most 

recent available data. All dollar values are expressed in 2009 dollars. 

2.8.2.9 Product Energy Efficiency in the Base Case 

For the purpose of conducting the LCC analysis, DOE analyzed candidate standard levels 

relative to a base case (i.e., a case without new energy conservation standards). This required 

estimating the distribution of product efficiencies in the base case (i.e., what consumers would 

have purchased in 2013 in the absence of new standards). Rather than assuming that all 

consumers will purchase products at the baseline efficiency level when it analyzed the impacts of 

a particular standard level, DOE conducted the analysis to account for the wide range of product 

energy efficiencies that consumers are expected to purchase under the base case. 

DOE’s approach for conducting the LCC analysis for BCs and EPSs relied on developing 

samples of consumers that use each of the products and using a Monte Carlo simulation 

technique to perform the LCC calculations on the consumers in the sample. DOE assigned each 

consumer in the sample a unique product energy efficiency level taken from the estimated base 

case distribution of product energy efficiencies in the compliance year. The energy efficiency 

distributions used for each application and each representative unit are presented in chapter 3 of 

the TSD. The applications assigned to each representative unit and their respective energy 

efficiency distribution are explained in further detail in Appendix 8C. 

DOE calculated the efficiency distributions by evaluating tested efficiency data for each 

representative unit. The tested efficiencies were then binned into the appropriate standards level 

and weighted by the shipments of the application tested. DOE assumed that the current averages 

for BCs are reasonable to use as a base case for 2013, but assumed a modest improvement in 

EPS efficiency from 2009 to 2013. This is because efficiency standards requiring EPSs to meet 

an ENERGY STAR level (CSL 1) will take effect in year 2010 in Europe. DOE assumes this 

will impact the American market by shifting EPS efficiencies higher by year 2013. Further detail 

on this analysis can be found in chapter 9 of the TSD. 

2.8.3 Payback Period 

As described above, the PBP is the amount of time it takes the customer to recover the 

assumed additional installed cost of more efficient products through energy cost savings. 

Payback analysis is a common technique used to evaluate investment decisions. This calculation 

is known as a simple payback period because it does not account for changes in operating 

expense over time or the time value of money. 

The inputs to the PBP calculation are the total installed costs of the product to the end 

user for each efficiency level and the annual (first-year) operating expenditures for each 

efficiency level. The PBP calculation uses the same inputs as the LCC analysis, except that 

energy price trends and discount rates are not needed. The calculation uses energy prices only for 

the year in which a new standard is expected to take effect, in this case 2013. 

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2.8.4 Sensitivity Analysis 

In addition to the Monte Carlo simulations used to characterize uncertainty and variation 

among the input values, DOE also considered two alternate sensitivity scenarios in the LCC and 

PBP analysis. The two sensitivities considered a positive or negative shift in the mean value 

associated with several key inputs, including: MSPs, lifetimes, usage profiles, and loading points 

(for EPSs only). DOE believes these sensitivities characterize the diversity of available data, and 

presents the results to highlight the impacts this diversity can have on the LCC and PBP. 

For the two sensitivity cases shown in Table 2.42, DOE simultaneously varied the inputs 

to obtain the highest and lowest possible LCC savings that could be reasonably expected based 

on the diversity seen in the data. While the reference case LCC results (explained previously) 

examine variability around a mean value for several inputs, the high-savings and low-savings 

sensitivities consider variability around a reasonably higher or lower mean input value. 

Appendix 8B presents the input values and resulting LCC and PBP projections for the highsavings and low-savings sensitivities. 

Table 2.42 Input Variations for the Sensitivity Analysis 

Input Reference Case Low Savings Case High Savings Case 

MSPs Original values Higher costs 

(MSP + average 

percentage error) 

Lower costs 

(MSP − average 

percentage error) 

Lifetimes Original values Shorter lifetimes Longer lifetimes 

Usage Profiles Original values Less time in use More time in use 

Loading Points 

(for EPSs only) 

Original values 

(60 percent for highest 

active mode state where 

no test data available) 

Lower values 

(40 percent for highest 

active mode state where 

no test data available) 

Higher values 

(80 percent from nonClass A EPS 

determination for highest 

active mode state where 

no test data available) 

2.9 SHIPMENTS ANALYSIS 

The shipments analysis generates shipment forecasts and efficiency forecasts for each of 

the BC and EPS product classes being considered for standards. The shipment forecasts are used 

in the NIA (chapter 10) and the MIA (chapter 12). The efficiency forecasts are used in the LCC 

(chapter 8), and the NIA. 

DOE made the following key assumptions in conducting the shipments analysis:
 

The market for BCs and EPSs will grow at the same rate as the resident population 

over the next 33 years.
 

Half of the Class A EPS market at CSL 0 in 2009 will have transitioned to CSL 1 by
 

2013.
 

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BCs will not become more efficient between 2009 and 2013. 

Products would not become more efficient after 2013 in the absence of new or
 

amended Federal standards.
 

Standards would have no impact on BC and EPS shipment volumes.
 

Manufacturers would respond to standards by improving those products that do not
 

meet the standards, while the products that were already as or more efficient than the 

standard would remain unaffected.
 

These assumptions are explained below and in chapter 9. 

2.9.1 Shipments Forecast 

The shipments forecast gives the total number of BCs and EPSs shipped each year. To 

create this forecast, DOE combined current year shipments, discussed in the market assessment 

(chapter 3), with a compound annual growth rate for BCs and EPSs and generated unit shipment 

values through the analysis period. 

2.9.1.1 Compound Annual Growth Rate 

DOE faces several challenges in calculating a compound annual growth rate. First, DOE 

must conduct its shipments forecast to account for 30 years of shipments. In addition, DOE must 

consider the entire potential market for BCs and EPSs, which could both include products that do 

not yet exist and exclude current products that may be discontinued before or during the analysis 

period. In addition, DOE found that many existing forecasts project out for only a few years, and 

most cover only a small number of BC and EPS applications. 

In light of these challenges, DOE concluded that the best methodology for approximating 

future market growth in the preliminary analysis would be to hold constant the current (2008) 

application mix and per-capita purchase rates for BCs and EPSs and account only for population 

growth. These assumptions are explained further in chapter 9. 

2.9.1.2 Impact of Standards on Shipments Forecast 

DOE considered the impact of standards on shipments in the MIA (chapter 12). In that 

analysis, manufacturers predicted that standards would have no negative impact on consumer 

consumption of EPSs due to cost increases. In addition, DOE has determined that the utility and 

functionality of an EPS minimizes the potential for substitution of alternative power sources. 

Therefore, DOE assumed that standards would have no impact on the volume of EPS shipments. 

DOE extended this assumption to hold true for BCs as well. 

2.9.2 Efficiency Forecast 

The efficiency forecast gives the distribution of EPS and BC shipments by CSL in the 

absence of standards (the base case). To develop its efficiency forecast, DOE first assessed 

present-day (2009) efficiency and then considered how the efficiency of new units might change 

by the first year of the analysis period (2013) and throughout the analysis period in the absence 

of new or amended Federal standards. 

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2.9.2.1 Base Year Efficiency Distribution 

DOE estimated the efficiency distribution in 2009 for each product class using currently 

available market and test data, as discussed in chapter 3. 

2.9.2.2 Effects from Outside EPS and BC Standards 

DOE considered the impact of outside standards for BCs and EPSs on the efficiency 

distribution in 2013 and beyond. 

For BCs, DOE found that, with the exception of Canada, there were no BC standards 

slated to take effect by 2013, and minimal participation by BC manufacturers in voluntary 

programs such as ENERGY STAR. In light of this, DOE could find no compelling evidence that 

battery charging systems will improve in efficiency in the short term and, consistent with these 

facts, assumed that the current efficiency distributions for BCs would be reasonable to use as a 

base case forecast for the entire analysis period. 

For EPSs, however, DOE found some programs, both voluntary and mandatory, that are 

likely to influence EPS efficiency in the short term. These programs, such as ENERGY STAR in 

the United States (voluntary) and the ecodesign requirements for external power supplies (EC 

No. 278/20093

) in Europe (mandatory), specify that Class A EPSs meet or beat CSL 1. With this 

in mind, and given the global nature of the EPS manufacturing industry, DOE estimated that in 

the United States approximately half of the Class A EPS market at CSL 0 in 2009 would 

transition to CSL 1 by 2013. DOE will update and refine this estimate in advance of publishing 

the NOPR. 

2.9.2.3 Effects from Current Class A EPS Standards 

In the framework document, DOE presented its preliminary assessment of the potential 

for current Federal standards for Class A EPSs to affect non-Class A EPS efficiency. DOE noted 

that the construction of certain non-Class A EPSs (specifically EPSs for medical devices and 

certain battery-charged products) was similar to that of Class A EPSs and that these similarities 

made it likely that efficiency improvements for Class A EPSs would transfer to these other EPSs. 

Therefore, in the present analysis DOE assumes that by the first year of the analysis period 

(2013) EPSs for medical devices and certain battery charged products will be just as efficient as 

Class A EPSs were in 2009. 

During the framework document public meeting, Micro Power Electronics, which 

primarily serves the commercial, medical, and military markets, commented that ―EPS efficiency 

standards that started in the household-use area (like ENERGY STAR and CEC) have migrated 

into our market areas.‖ (MPE, No. 5 at p. 1) DOE believes that this comment provides support 

for its assumption that the standards currently in effect for Class A EPSs will lead to efficiency 

improvements in certain non-Class A EPSs as well. 

2.9.2.4 Market Response to Standards 

DOE considered how the mix of product efficiencies might change due to new or 

amended Federal standards. In its preliminary analysis, DOE assumed that manufacturers would 

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respond to standards by improving those products that do not meet the standards to meet the 

standard level, but not higher, while the products that were already as or more efficient than the 

standard would remain unaffected. 

2.10 NATIONAL IMPACT ANALYSIS 

The national impact analysis estimates energy savings and assesses the NPV of consumer 

LCC savings at the national scale. The results can be used to identify the CSL that, for a given 

product class, yields the greatest energy savings while remaining cost effective from a consumer 

perspective. DOE estimated both NES and NPV for all candidate standard levels for each BC 

and EPS product class. To make the analysis more accessible and transparent to all interested 

parties, it is documented in a Microsoft Excel spreadsheet model that can be downloaded from 

the EERE website. 

The NIA considers total installed cost (which includes manufacturer selling prices, 

distribution chain markups, sales taxes, and installation costs), operating expenses (energy, 

repair, and maintenance costs), product lifetime, and discount rate. However, where the LCC 

considers the savings and costs associated with standards for a set of representative units, the 

NIA considers the savings and costs associated with all units affected by standards during the 

entire analysis period. Chapter 10 provides additional details regarding the NIA. 

DOE made the following key assumptions in conducting the NIA: 

Products remain in the installed base for an integral number of years (no fractional 

years)
 

All energy cost savings accrue at residential electricity prices.
 

These assumptions are explained below and in chapter 10.
 

DOE’s estimates of NES and NPV for BCs and EPSs should not be added to one another 

because many BCs incorporate an EPS. One way to improve the efficiency of these BCs is to 

improve the efficiency of the EPS part. The resulting savings are counted in both the BC analysis 

and in the separate EPS analysis. Thus, due to this overlap, combining BC and EPS NES (or 

NPV) estimates would overstate savings resulting from improving BCs and EPSs. 

2.10.1 Approach 

DOE conducted the NIA by combining unit costs and unit energy consumption with 

efficiency distributions and shipments over a shipment forecast period of 30 years and an 

analysis period extending until all units shipped during the shipment forecast period are retired 

from use. Energy savings were compared between a base case and multiple standards cases, 

yielding NES estimates. Unit improvement costs and energy cost savings were then discounted 

to the present day (2010) and compared to one another, yielding NPV estimates. 

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DOE conducted an NIA sensitivity analysis that mirrored the LCC sensitivity analysis, 

which is explained briefly in section 2.8.4. For additional explanation of how inputs varied 

between the low-savings, reference, and high-savings scenarios see appendix 8B. 

2.10.2 NIA Inputs 

The NIA requires a number of inputs, summarized in Table 2.43. Many are the same as 

those required for the LCC. These shared inputs are detailed in Section 2.8.2. Variations from the 

LCC include the use of different discount rates and the extension of shipments and efficiency 

forecasts beyond 2013. 

Table 2.43 Summary of Inputs Used in the National Impact Analysis 

Input Characterization 

Manufacturers Selling Price Varies with BC and EPS product class, from chapter 5. 

Markups Varies with BC and EPS product class, from chapter 6. 

Sales Tax U.S. National Average, from chapter 6. 

Installation Cost No installation cost associated with BCs or EPSs. 

Unit Energy Consumption Varies with BC and EPS product class and by efficiency level, from chapter 7. 

Electricity Prices and Trends U.S. National Average Residential, varied with forecast scenario, from chapter 8. 

Site-to-Source Conversion U.S. National Average Rate. 

Repair and Maintenance Costs No repair or maintenance costs associated with BCs or EPSs. 

Shipments Varies with BC and EPS product class, from chapter 9. 

Lifetime Varies with BC and EPS product class, from chapter 3. 

Discount Rate 3% and 7%, as specified by the Office of Management and Budget. 

Efficiency Distribution in 

2013 

Varies with BC and EPS product class, from chapter 9. 

As noted above, while the LCC analysis weighs the costs and savings associated with 

standards for a set of representative units, the NIA considers the costs and savings associated 

with standards for all products, including those in the ―scaled‖ product classes. For these scaled 

product classes, most inputs to the NIA could be obtained in the same manner as for the 

representative product classes. However, cost data were not available for the scaled product 

classes, as they were not directly analyzed in the engineering analysis. Therefore, as is done in 

other rulemakings, DOE extrapolated from its knowledge of costs for the representative product 

classes to the scaled product classes. Costs from the 2.5 W EPS representative unit were applied 

to product classes A2 and A4, and costs from the 18 W EPS representative unit were applied to 

product class A3. Costs for BC product classes 3, 6, 8, and 9 were derived from cost data for the 

representative product classes as described in chapter 5. 

2.10.3 National Energy Savings Analysis 

The major inputs for determining the NES for each product analyzed are annual unit 

energy consumption, shipments, lifetimes, and site-to-source conversion factors. DOE calculated 

national energy consumption for each year by multiplying unit energy consumption by the 

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number of units in the installed base in that year. NES for a given year, then, is the difference in 

national energy consumption between the base case (without new efficiency standards) and each 

standards case. DOE estimated energy consumption and savings first in terms of site energy and 

then converted the savings into source energy. Cumulative energy savings are the sum of the 

NES estimates for each year. 

2.10.4 Net Present Value Analysis 

The major inputs for determining NPV are installed costs, annual operating cost savings, 

and discount rates. For each standards case, DOE calculated net savings each year as the 

operating cost savings less any increase in installed costs due to the standard. DOE calculated 

operating cost savings over the life of each product, accounting for changes in electricity prices 

over time. DOE calculated NPV as the present value of operating cost savings less the present 

value of increased installed costs. DOE used discount rates of 3 percent and 7 percent to discount 

future costs and savings to present values to reflect the time value of money. 

In the preliminary analysis, DOE assumed that all energy cost savings will accrue at 

residential electricity prices. Since commercial electricity prices are lower, the national energy 

cost savings estimates are slightly overestimated to the extent that some BCs and EPSs are used 

in the commercial sector. The NIA workbook contains both residential and commercial price 

forecasts and a control for choosing a sector split, should sensitivity analysis be necessary in the 

NOPR stage. 

2.11 LIFE-CYCLE COST SUBGROUP ANALYSIS 

The LCC subgroup analysis will evaluate consumer impacts by identifying consumer 

subgroups and accounting for variations in key inputs to the LCC analysis. A consumer subgroup 

comprises a subset of the population that is likely, for one reason or another, to be impacted 

disproportionately by new or revised energy conservation standards. The purpose of a subgroup 

analysis is to determine the extent of this disproportional impact. During the NOPR stage, DOE 

intends to evaluate the impacts of particular subgroups of customers in part by analyzing the 

LCC for these particular customers. 

DOE intends to evaluate variations in usage profiles and regional electricity prices, such 

as customers with steeply inclined marginal block rates (resulting in electricity prices higher than 

the average price), to see what type of effect an energy efficiency standard would have on the 

NPV for these customer subgroups. Additionally, DOE may consider evaluating LCC impacts on 

a subgroup of applications within a representative unit. To the extent possible, DOE plans to 

determine estimates of the variability of each input parameter and consider this variability in its 

calculation of customer impacts. DOE intends to perform sensitivity analyses to consider how 

differences in energy use will affect various subgroups of customers. 

DOE will determine the effect on customer subgroups using the LCC spreadsheet model. 

The spreadsheet model used for the LCC analysis can be used with different data inputs. The 

standard LCC analysis includes various customer types that use BCs and EPSs. DOE can analyze 

the LCC for any subgroup by using the LCC spreadsheet model and sampling only that 

subgroup. The model is explained in chapter 8 of the preliminary TSD, which describes the LCC 

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and PBP analyses. DOE will be especially sensitive to potential negative economic impacts on 

identifiable population groups such as small businesses (i.e., those with low annual revenues), 

which may not be able to afford a substantial increase in the price of BCs or EPSs. 

PG&E commented that DOE should especially consider the effect of standards on low 

income users and small businesses. (PG&E, Pub. Mtg. Tr., No. 14 at pp. 46, 351) PG&E also 

commented that DOE should consider consumers with electricity prices that are higher than the 

average rate of electricity, which it suggests may be more likely for BC and EPS users. (PG&E, 

Pub. Mtg. Tr., No. 14 at p. 363) One way that PG&E suggested doing this would be to perform 

regional sensitivity using top-tier residential electricity prices rather than average electricity 

rates. (PG&E, No. 20 at pp. 10, 358) DOE acknowledges these comments, and will revisit them 

in the NOPR. 

2.12 PRELIMINARY MANUFACTURER IMPACT ANALYSIS 

The purpose of the MIA is to identify the likely impacts of higher energy conservation 

standards on manufacturers. DOE will identify and discuss a wide range of quantitative and 

qualitative industry impacts in interviews with manufacturers and other interested parties during 

the NOPR stage of the analysis. DOE will use the manufacturer interviews as well as the 

methodology described below in its evaluation of standards for BCs and EPSs. 

DOE will conduct the MIA in three phases, and will further tailor the analytical 

framework based on the comments it receives. In Phase I, DOE creates an industry profile to 

characterize the industry and identify important issues that require consideration. In Phase II, 

DOE prepares an industry cash-flow model and an interview questionnaire to guide subsequent 

discussions. In Phase III, DOE interviews manufacturers and assesses the impacts of standards 

both quantitatively and qualitatively. DOE assesses industry and subgroup cash flow and NPV 

using the Government Regulatory Impact Model (GRIM). DOE then assesses impacts on 

competition, manufacturing capacity, employment, and regulatory burden based on manufacturer 

interview feedback and discussions. 

Until recently, DOE reported MIA results in its standards rulemakings only in the NOPR 

stage of the rulemaking. However, DOE is now evaluating and reporting preliminary MIA 

information at this preliminary analytical stage. DOE gathered the information for the analysis 

during the manufacturer interviews conducted after the engineering analysis. See chapter 12 of 

the preliminary TSD for more detail on the MIA. 

2.12.1 Sources of Information for the MIA 

Many of the analyses described above provide important information applicable to the 

MIA. Such information includes manufacturing costs and prices from the engineering analysis, 

as well as retail price and shipment forecasts. DOE will supplement this information with 

company financial data and other information gathered during interviews with manufacturers. 

The interview process plays a key role in the MIA because it allows interested parties to 

privately express their views on important issues. DOE’s contractor has a non-disclosure 

agreement in place with interviewees to allow consideration of confidential or sensitive 

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information in the decision-making process. Confidential information will not be made available 

in the public record. To preserve confidentiality, DOE’s contractor aggregates these perspectives 

across manufacturers, creating a combined opinion or estimate for DOE to use in analyzing the 

impacts standards will have on manufacturers. This process enables DOE to account for sensitive 

information shared by manufacturers during the rulemaking process. 

The process also includes detailed interviews with manufacturers to gain insight into the 

range of potential impacts of standards. Typically, the interviews solicit both quantitative and 

qualitative information on the potential impacts of efficiency levels on sales, direct employment, 

capital assets, and industry competitiveness. An interactive interview process, rather than a 

written response to a questionnaire, is used because it helps clarify responses and identify 

additional issues. Before the interviews, a draft document showing estimates of the financial 

parameters based on publicly available information will be circulated. Comments on these 

estimates will also be solicited during the interviews. See chapter 12 of the preliminary TSD for 

more detail on the methodology used in the MIA. 

2.12.2 Industry Cash-Flow Analysis 

The industry cash-flow analysis relies primarily on the GRIM. DOE uses the GRIM to 

analyze the financial impacts of more stringent energy conservation standards on the industry. 

The GRIM analysis uses several factors to determine annual cash flows from an amended 

energy conservation standard: annual expected revenues; manufacturer costs, including cost of 

goods sold, depreciation, research and development, selling, and general and administrative 

expenses; taxes; and conversion capital expenditures. DOE compares the results against base 

case projections that involve no amended energy conservation standards. The financial impact of 

amended energy conservation standards is the difference between the two sets of discounted 

annual cash flows. Other performance metrics, such as return on invested capital, also are 

available from the GRIM. See chapter 12 of the preliminary TSD for more information on the 

industry cash-flow analysis. 

2.12.3 Manufacturer Subgroup Analysis 

Industry cost estimates are inadequate to assess differential impacts among subgroups of 

manufacturers because these subgroups may have different cost structures or regulatory 

frameworks that affect their respective business models. For example, small and niche 

manufacturers, or manufacturers whose cost structure differs significantly from the industry 

average, could experience a more negative impact. While considering impacts on an individual 

firm basis would be ideal, such an approach is typically impractical given the number of firms 

involved. In place of this approach, DOE typically groups manufacturers exhibiting similar 

characteristics together to characterize the industry. 

During the interview process, DOE will discuss the potential subgroups and subgroup 

members it has identified for the analysis. DOE will encourage manufacturers to recommend 

subgroups or characteristics that are appropriate for the subgroup analysis. See chapter 12 of the 

preliminary TSD for more detail on the manufacturer subgroup analysis. 

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2.12.4 Competitive Impacts Assessment 

Section 325(o)(2)(B)(i)(V) of EPCA (codified at 42 U.S.C. § 6295(o)(2)(B)(i)(V)) directs 

DOE to consider any lessening of competition likely to result from imposition of standards. DOE 

will consider whether an amended energy conservation standard is likely to reduce industry 

competition and will ask the Attorney General to determine the impacts, if any. The assessment 

will be based on manufacturing cost data and information collected from manufacturer 

interviews. DOE will make a determined effort to gather and report firm-specific financial 

information and impacts. 

2.12.5 Cumulative Regulatory Burden 

DOE recognizes and seeks to mitigate the overlapping effects on manufacturers of new or 

amended DOE standards and other regulatory actions affecting the same equipment. DOE will 

analyze and consider the impact on manufacturers of multiple, equipment-specific regulatory 

actions. 

During the public meeting, the American Council for an Energy-Efficient Economy 

commented that there is current legislation in Congress intended to help manufacturers offset 

conversion costs. DOE should take this legislation into account if it is passed. (ACEEE, Pub. 

Mtg. Tr., No. 14 at p. 343) 

In its response to these comments, DOE stated that although it continues to track 

upcoming legislation, it cannot incorporate legislative proposals into its analysis until the 

proposals become law. 

2.12.6 Preliminary Results for the Manufacturer Impact Analysis 

DOE conducted a series of preliminary interviews with manufacturers to discuss impacts 

that may result from regulatory standards for battery chargers and external power supplies. 

Related to standards for external power supplies, manufacturers and other parties identified four 

general areas of concern: (a) impacts on shipments and (b) timing, (c) efficiency levels, and (d) 

regulatory approval. These concerns are described briefly in the following paragraphs; please 

see TSD chapter 12 for a more complete description of these concerns. 

2.12.7 Impacts on Shipments 

Manufacturers stated that if exceptionally stringent standards caused costs and prices to 

rise, shipments could be affected. 

2.12.8 Timing 

Some manufacturers commented that if standards were to be implemented in a period of 

less than six months to a year, manufacturers would be forced to write off old inventory that they 

could no longer sell. 

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2.12.9 Efficiency Levels 

One manufacturer was concerned that if the rulemaking process took too much time to 

complete, new standards could be lower than efficiency levels the industry had already reached. 

2.12.10 Regulatory Approval 

Some manufacturers mentioned that regulatory approval for new products can come at a 

significant cost while also requiring a substantial amount of time. 

Related to standards for battery chargers, manufacturers and other parties identified three 

general areas of concern: (a) conversion costs, (b) efficiency as a selling point, and (c) profit 

margins. 

2.12.11 Conversion Costs 

Manufacturers stated that significant cost and time is required for testing and obtaining 

safety approval for new products. Especially stringent standards would require significant capital 

conversion costs. 

2.12.12 Efficiency as a Selling Point 

Some manufacturers commented that energy efficiency is not an important consideration 

for buyers of battery chargers. The important factors to consumers are price and quality. 

2.12.13 Profit Margins 

Multiple manufacturers stated that new standards could raise product costs and hurt 

manufacturer’s profit margins. These manufacturers asserted that they have been unable to pass 

on increases in product costs to consumers in the past. 

2.13 UTILITY IMPACT ANALYSIS 

The utility impact analysis includes an analysis of the effects of new energy conservation 

standards on the electric utility industry. For this analysis, DOE adapted NEMS, which is a large, 

multi-sectoral, partial-equilibrium model of the U.S. energy sector that the EIA has developed 

throughout the past decade, primarily for preparing EIA’s Annual Energy Outlook (AEO). In 

previous rulemakings, a variant of NEMS (currently termed NEMS-BT, BT referring to DOE’s 

Building Technologies Program), was developed to better address the specific impacts of an 

energy conservation standard. NEMS, which is available in the public domain, produces a widely 

recognized baseline energy forecast for the United States through the year 2035. The typical 

NEMS outputs include forecasts of electricity sales, prices, and electric generating capacity. 

DOE typically conducts the utility impact analysis as a scenario that departs from the 

latest AEO reference case. In other words, the energy savings impacts from amended energy 

conservation standards are modeled using NEMS-BT to generate forecasts that deviate from the 

AEO reference case. 

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2.14 EMPLOYMENT IMPACT ANALYSIS 

The imposition of standards can affect employment both directly and indirectly. Direct 

employment impacts are changes, produced by new standards, in the number of employees at 

plants that produce the covered products and at the affiliated distribution and service companies. 

DOE evaluated direct employment impacts in the manufacturer impact analysis. Indirect 

employment impacts that occur because of the imposition of standards may result from 

consumers shifting expenditures between goods (the substitution effect) and from changes in 

income and overall expenditure levels (the income effect). 

DOE plans to utilize Pacific Northwest National Laboratory’s impact of sector energy 

technologies (ImSET) model to investigate the combined direct and indirect employment 

impacts. The ImSET model, which was developed for DOE’s Office of Planning, Budget, and 

Analysis, estimates the employment and income effects energy-saving technologies produced in 

buildings, industry, and transportation. In comparison with simple economic multiplier 

approaches, ImSET allows for more complete and automated analysis of the economic impacts 

of energy conservation investments. 

2.15 ENVIRONMENTAL ASSESSMENT 

Pursuant to the National Environmental Policy Act of 1969 (NEPA) (42 U.S.C. 4321 et 

seq.) 42 U.S.C. 6295(o)(2)(B)(i)(VI), DOE intends to prepare a assessment (EA) of the potential 

impacts that will quantify and consider the environmental effects of new or amended energy 

conservation standards for battery chargers and external power supplies. The primary 

environmental effects of these standards would be reduced power plant emissions resulting from 

reduced consumption of electricity. DOE will assess these environmental effects by using 

NEMS-BT to provide key inputs to its analysis. The portion of the environmental assessment 

that will be produced by NEMS-BT considers carbon dioxide (CO2), nitrogen oxides (NOX), and 

mercury (Hg). The environmental assessment also considers impacts on SO2 emissions. After a 

brief discussion of general methodology, this section will address each of the relevant emissions. 

This section then explains how DOE plans to monetize the benefits associated with emissions 

reductions. 

2.15.1 Carbon Dioxide 

In the absence of any Federal emissions control regulation of power plant emissions of 

CO2, a DOE standard is likely to result in reductions of these emissions. The CO2 emission 

reductions likely to result from a standard will be estimated using NEMS-BT and national energy 

savings estimates drawn from the NIA spreadsheet model. The net benefit of the standard is the 

difference between emissions estimated by NEMS-BT at each standard level considered and the 

AEO Reference Case. NEMS-BT tracks CO2 emissions using a detailed module that provides 

results with broad coverage of all sectors and inclusion of interactive effects. 

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2.15.2 Sulfur Dioxide 

DOE has determined that SO2 emissions from affected Electric Generating Units (EGUs) 

are subject to nationwide and regional emissions cap and trading programs that create 

uncertainty about the standards’ impact on SO2 emissions. The costs of meeting such emission 

cap requirements are reflected in the electricity prices and forecasts used in DOE’s analysis of 

the standards. Title IV of the Clean Air Act sets an annual emissions cap on SO2 for all affected 

EGUs. SO2 emissions from 28 eastern States and the District of Columbia (DC) are also limited 

under the Clean Air Interstate Rule (CAIR, published in the Federal Register on May 12, 2005. 

70 FR 25162 (May 12, 2005)), which creates an allowance-based trading program that will 

gradually replace the Title IV program in those States and DC. (The recent legal history 

surrounding CAIR is discussed below.) The attainment of the emissions caps is flexible among 

EGUs and is enforced through the use of emissions allowances and tradable permits. Under 

existing EPA regulations, any excess SO2 emission allowances resulting from the lower 

electricity demand caused by the imposition of an efficiency standard could be used to permit 

offsetting increases in SO2 emissions by any regulated EGU. However, if the standard resulted in 

a permanent increase in the quantity of unused emission allowances, there would be an overall 

reduction in SO2 emissions from the standards. While there remains some uncertainty about the 

ultimate effects of efficiency standards on SO2 emissions covered by the existing cap and trade 

system, the NEMS-BT modeling system that DOE plans to use to forecast emissions reductions 

currently indicates that no physical reductions in power sector emissions would occur for SO2. 

2.15.3 Nitrogen Oxides 

NEMS-BT also has an algorithm for estimating NOX emissions from power generation. 

The impact of these emissions, however, will be affected by the CAIR, which the Environmental 

Protection Agency (EPA) issued on May 12, 2005. CAIR will permanently cap emissions of 

NOX in 28 eastern states and the District of Columbia. 70 FR 25162 (May 12, 2005). 

Much like SO2 emissions, a cap on NOX emissions means that battery charger and 

external power supply standards may have little or no physical effect on these emissions in the 

region covered by CAIR. Although CAIR has been remanded to the EPA by the DC Circuit, it 

will remain in effect until it is replaced by a rule consistent with the Court’s July 11, 2008, 

opinion in North Carolina v. EPA. 531 F.3d 896 (DC Cir. 2008); see also North Carolina v. 

EPA, 550 F.3d 1176 (DC Cir. 2008). Because all States covered by CAIR opted to reduce NOX 

emissions through participation in cap-and-trade programs for electric generating units, 

emissions from these sources are capped across the CAIR region. 

DOE plans to use NEMS-BT to estimate the emissions reductions from possible 

standards in the 22 States where emissions are not capped. 

2.15.4 Mercury 

Similar to emissions of SO2 and NOX, future emissions of Hg would have been subject to 

emissions caps. In May 2005, EPA issued the Clean Air Mercury Rule (CAMR). 70 FR 28606 

(May 18, 2005). CAMR would have permanently capped emissions of mercury for new and 

existing coal-fired power plants in all States by 2010. However, on February 8, 2008, the DC 

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Circuit issued its decision in New Jersey v. Environmental Protection Agency, in which the DC 

Circuit, among other actions, vacated the CAMR. 517 F.3d 574 (DC Cir. 2008). EPA has 

decided to develop emissions standards for power plants under the Clean Air Act (Section 112), 

consistent with the DC Circuit’s opinion on the CAMR. See 

http://www.epa.gov/air/mercuryrule/pdfs/certpetition_withdrawal.pdf. Pending EPA's 

forthcoming revisions to the rule, DOE is excluding the CAMR from its environmental analysis. 

In the absence of CAMR, a DOE standard would likely reduce Hg emissions and DOE plans to 

use NEMS-BT to estimate these emission reductions. However, DOE continues to review the 

impact of rules that reduce energy consumption on Hg emissions and may revise its assessment 

of Hg emissions reductions in future rulemakings. 

2.15.5 Particulate Matter 

Earthjustice commented that ―the significant contribution of power plants to [particulate 

matter (PM)] pollution requires DOE to evaluate the impact of efficiency standards on PM 

emissions.‖ To support this statement, Earthjustice elaborated that power plants emit ―7.2% of all 

anthropogenic PM10 and 20.4% of all anthropogenic PM2.5.‖ (Earthjustice, No. 18 at p. 3) 

DOE acknowledges that particulate matter (PM) impacts are of concern due to human 

exposures that can impact health. However, impacts of PM emissions reduction are much more 

difficult to estimate than other emissions reductions due to the complex interactions between 

PM, other power plant emissions, meteorology, and atmospheric chemistry that affect human 

exposure to particulates. Human exposure to PM usually occurs at a significant distance from the 

power plants that are emitting particulates and particulate precursors. When power plant 

emissions travel this distance, they undergo highly complex atmospheric chemical reactions. 

Although the EPA does keep inventories of direct PM emissions of power plants, in its source 

attribution reviews the EPA does not separate direct PM emissions from power plants from the 

sulfate particulates indirectly produced through complex atmospheric chemical reactions. The 

great majority of PM emissions from power plants are of these secondary particles (secondary 

sulfates). Thus, it is not useful to examine how new or amended standards impact direct PM 

emissions independent of indirect PM production and atmospheric dynamics. Therefore, DOE is 

not planning to assess the impact of these standards on particulate emissions. Further, even the 

cumulative impact of PM emissions from power plants and indirect emissions of pollutants from 

other sources is unlikely to be significant. 

2.15.6 Monetization of Emissions Reduction Benefits 

For those emissions for which real national emission reductions are anticipated (CO2, Hg, 

and NOX for 22 states), only ranges of estimated economic values based on environmental 

damage studies of varying quality and applicability are available. Therefore, DOE intends to 

report estimates of monetary benefits derived using these values and consider these benefits in 

weighing the costs and benefits of each of the standard levels considered. 

In order to estimate the monetary value of benefits resulting from reduced emissions of 

CO2 emissions, it is DOE’s intent to use in its analysis the most current Social Cost of Carbon 

(SCC) values developed and/or agreed to by interagency reviews. The SCC is intended to be a 

monetary measure of the incremental damage resulting from greenhouse gas (GHG) emissions, 

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including, but not limited to, net agricultural productivity loss, human health effects, property 

damage from sea level rise, and changes in ecosystem services. Any effort to quantify and to 

monetize the harms associated with climate change will raise serious questions of science, 

economics, and ethics. But with full regard for the limits of both quantification and monetization, 

the SCC can be used to provide estimates of the social benefits of reductions in GHG emissions. 

At the time of this notice, the most recent interagency estimates of the potential global 

benefits resulting from reduced CO2 emissions in 2010 were $4.70, $21.40, $35.10, and $64.90 

per metric ton in 2007 dollars. These values are then adjusted to 2009 dollars using the standard 

GDP deflator value for 2008 and 2009. For emissions (or emission reductions) that occur in later 

years, these values grow in real terms over time. Additionally, the interagency group determined 

that a range of values from 7 percent to 23 percent should be used to adjust the global SCC to 

calculate domestic effects, although preference will be given to consideration of the global 

benefits of reducing CO2 emissions. See appendix 15A of the TSD preliminary analysis for the 

full range of annual SCC estimates from 2010 to 2050. To calculate a present value of the stream 

of monetary values, DOE will discount the values in each of the four cases using the discount 

rates that had been used to obtain the SCC values in each case. 

DOE recognizes that scientific and economic knowledge continues to evolve rapidly as to 

the contribution of CO2 and other GHG to changes in the future global climate and the potential 

resulting damages to the world economy. Thus, these values are subject to change. 

DOE also intends to estimate the potential monetary benefit of reduced NOX emissions 

resulting from the standard levels it considers. For NOX emissions, available estimates suggest a 

very wide range of monetary values, ranging from $370 per ton to $3,800 per ton of NOX from 

stationary sources, measured in 2001$ (equivalent to a range of $447 to $4,591 per ton in 

2009$). Refer to the OMB, Office of Information and Regulatory Affairs, ―2006 Report to 

Congress on the Costs and Benefits of Federal Regulations and Unfunded Mandates on State, 

Local, and Tribal Entities,‖ for additional information. In accordance with U.S. Office of 

Management and Budget (OMB) guidance, DOE will conduct two calculations of the monetary 

benefits derived using each of the economic values used for NOX, one using a real discount rate 

of 3 percent and another using a real discount rate of 7 percent.j 

DOE does not plan to monetize estimates of Hg in this rulemaking. DOE is aware of 

multiple agency efforts to determine the appropriate range of values used in evaluating the 

potential economic benefits of reduced Hg emissions. DOE has decided to await further guidance 

regarding consistent valuation and reporting of Hg emissions before it once again monetizes Hg 

in its rulemakings. 

2.16 REGULATORY IMPACT ANALYSIS 

In the NOPR stage, DOE will prepare a regulatory impact analysis (RIA) pursuant to 

Executive Order 12866, Regulatory Planning and Review, 58 FR 51735, October 4, 1993, which 

is subject to review under the Executive Order by the Office of Information and Regulatory 

Affairs at the Office of Management and Budget. The RIA addresses the potential for nonj OMB, Circular A-4: Regulatory Analysis (Sept. 17, 2003). 

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regulatory approaches to supplant or augment energy conservation standards in order to improve 

the energy efficiency or reduce the energy consumption of the products covered under this 

rulemaking. 

DOE recognizes that voluntary or other non-regulatory efforts by manufacturers, utilities, 

and other interested parties can substantially affect energy efficiency or reduce energy 

consumption. DOE plans to base its assessment on the actual impacts of any such initiatives to 

date, but also will also consider, to the extent possible, information presented by interested 

parties regarding the impacts existing initiatives might have in the future. 

2.17 ADDITIONAL COMMENTS FROM INTERESTED PARTIES 

DOE received several additional comments it wishes to acknowledge here that do not 

pertain directly to the preliminary analyses. 

2.17.1 Temporary Exemptions from Standards for Replacement Parts 

An ITI member company requested that DOE ―include an exemption from test and 

regulation for service parts (battery packs & external power supplies) intended for systems 

manufactured prior to any regulatory effective date.‖ (ITI member, No. 17 at p. 1) 

According to section 325 of EPCA, as modified by EISA 2007, a Class A EPS is 

excluded from standards if it is: 

(i) manufactured during the period beginning on July 1, 2008, and ending on June 30, 

2015; and 

(ii) made available by the manufacturer as a service part or a spare part for an end-use 

product— 

(I) that constitutes the primary load; and 

(II) was manufactured before July 1, 2008 (42 U.S.C. § 6295(u)(3)(B)). 

The statutory language supports the ITI member’s request by excluding any EPS service 

part for an end-use product manufactured before July 2008. This exclusion allows manufacturers 

to make EPS spare parts until 2015 for end-use products manufactured prior to the compliance 

date of the Class A standard. There are no similar exclusions for non-Class A EPSs or BCs. 

2.17.2 Labeling Requirements and Marking Protocol 

An ITI member company requested that DOE not require any international efficiency 

markings, e.g., IV or V, on battery charger systems. (ITI member, No. 17 at p. 1) DOE may 

prescribe labeling requirements for any covered product for which a test procedure has been 

prescribed. (42 U.S.C. § 6294(a)(5)) While DOE has not prescribed labeling requirements for 

BCs or non-Class A EPSs, it reserves the right to do so at a later date, particularly if labeling 

would aid in the identification of compliant products. 

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2.17.3 Standards Compliance and Enforcement 

Vivitar pointed out that Federal government agencies regulating the toy, leather, and 

textile industries have sought the assistance of test laboratories in their efforts to boost regulatory 

compliance and suggested that DOE do the same. (Vivitar, Pub. Mtg. Tr., No. 14 at p. 377) DOE 

appreciates this comment and will consider educating test laboratories on how to facilitate 

compliance with BC and EPS standards as part of its broader compliance and enforcement 

efforts. 

2.17.4 Publishing Public Comments on the Internet 

ASAP and Earthjustice both requested that public comments be made available online. 

(ASAP, Pub. Mtg. Tr., No. 14 at p. 39; Earthjustice, Pub. Mtg. Tr., No. 14 at p. 47) DOE is 

exploring options for doing so. 

2.17.5 Public Meeting Webcast 

ASAP expressed support for DOE’s webcasting of the framework public meeting, noting 

that this type of effort improves public accessibility to the rulemaking process accessible to the 

public. (ASAP, Pub. Mtg. Tr., No. 14 at p. 39) DOE will continue to make efforts to ensure 

public participation in its rulemaking process. 

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REFERENCES 

1 Pacific Gas and Electric Company, ―Proposal Information Template for: Battery Charger Systems‖, submitted to 

the California Energy Commission, 2008 Rulemaking Proceeding on Appliance Efficiency Regulations, Docket 

Number 07-AAER-3, 2008 

2 Taken in September 2009 from the ENERGY STAR 2.0 database at 

http://www.energystar.gov/index.cfm?fuseaction=find_a_product.showProductGroup&pgw_code=ACD 

3 Commission Regulation (EC) No. 278/2009 of April 6, 2009 implementing Directive 2005/32/EC of the European 

Parliament and of the Council with regard to ecodesign requirements for no-load condition electric power 

consumption and average active efficiency of external power supplies. 

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EERE-2008-BT-STD-0005 COMMENT 31
CHAPTER 3. MARKET AND TECHNOLOGY ASSESSMENT
 

TABLE OF CONTENTS 

3.1 INTRODUCTION ........................................................................................................... 3-1
 

3.1.1 Definitions and Nomenclature ............................................................................. 3-1
 

3.1.1.1 Current Statutory Definitions................................................................... 3-1
 

3.1.1.2 Additional Definitions ............................................................................. 3-1
 

Wall Adapter............................................................................................ 3-2
 

Battery3-3
 

Battery Charging System ......................................................................... 3-3
 

3.1.2 Test Procedures.................................................................................................... 3-3
 

3.2 MARKET ASSESSMENT .............................................................................................. 3-6
 

3.2.1 Applications that Use BCs and EPSs................................................................... 3-6
 

3.2.1.1 Audio 3-7
 

MP3 Players............................................................................................. 3-8
 

MP3 Speaker Docks and Clock Radios ................................................... 3-8
 

Wireless Speakers .................................................................................... 3-8
 

3.2.1.2 Computers and Peripherals ...................................................................... 3-9
 

Computers................................................................................................ 3-9
 

Desktop Accessories .............................................................................. 3-10
 

Document Manipulation ........................................................................ 3-10
 

Document Readers................................................................................. 3-11
 

Networking ............................................................................................ 3-11
 

3.2.1.3 Geospatial Equipment............................................................................ 3-11
 

3.2.1.4 Telephony .............................................................................................. 3-12
 

Mobile Telephony.................................................................................. 3-13
 

GSMA Universal Charging Solution. .................................................... 3-13
 

Stationary Telephony............................................................................. 3-14
 

3.2.1.5 Household .............................................................................................. 3-15
 

Photo/Video ........................................................................................... 3-16
 

Floor Care .............................................................................................. 3-18
 

Kitchen Appliances................................................................................ 3-18
 

Childcare ................................................................................................ 3-19
 

Entertainment......................................................................................... 3-19
 

Home Systems ....................................................................................... 3-20
 

Other Household .................................................................................... 3-21
 

3.2.1.6 Outdoor Appliances ............................................................................... 3-21
 

3.2.1.7 Personal Care ......................................................................................... 3-22
 

3.2.1.8 Power Tools ........................................................................................... 3-24
 

3.2.1.9 Transport................................................................................................ 3-25
 

Electric Vehicles .................................................................................... 3-26
 

Mobility Devices.................................................................................... 3-27
 

3.2.2 Shipments, Lifetimes, and Energy Performance................................................ 3-27
 

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3.2.2.1 External Power Supply Shipments, Lifetimes and Energy Performance .. 3­

28
 

3.2.2.2 Battery Charger Shipments, Lifetimes and Energy Performance .......... 3-36
 

3.2.3 Other Energy Efficiency Programs.................................................................... 3-40
 

3.2.4 Production and Distribution............................................................................... 3-43
 

3.2.5 Small Businesses................................................................................................ 3-45
 

3.2.6 Manufacturers and Market Shares ..................................................................... 3-45
 

3.2.7 Trade Associations and Other Interested Parties ............................................... 3-46
 

3.3 PRODUCT CLASSES................................................................................................... 3-49
 

3.3.1 EPS Product Classes .......................................................................................... 3-49
 

3.3.1.1 Nameplate Output Power....................................................................... 3-49
 

3.3.1.2 Nameplate Output Voltage .................................................................... 3-51
 

3.3.1.3 Type of Power Conversion (AC/AC versus AC/DC) ............................ 3-52
 

3.3.1.4 Use with Medical Equipment................................................................. 3-52
 

3.3.1.5 Use with Battery Chargers of Motorized Applications and Detachable 

Batteries ................................................................................................. 3-53
 

3.3.1.6 EPS Product Classes Under Consideration............................................ 3-53
 

3.3.2 BC Product Classes............................................................................................ 3-54
 

3.3.2.1 BC Product Class Criteria Considered for the Preliminary Analysis .... 3-54
 

3.3.2.2 Impacts of Topology on Product Class Selection .................................. 3-56
 

3.3.2.3 Resultant BC Product Classes................................................................ 3-57
 

3.4 TECHNOLOGY ASSESSMENT.................................................................................. 3-58
 

3.4.1 Introduction........................................................................................................ 3-58
 

3.4.2 EPS Modes of Operation ................................................................................... 3-58
 

3.4.2.1 EPS Active Mode................................................................................... 3-58
 

3.4.2.2 EPS No-Load Mode............................................................................... 3-60
 

3.4.3 EPS Efficiency Metrics...................................................................................... 3-60
 

3.4.4 Energy Efficiency Metrics for External Power Supplies................................... 3-60
 

3.4.5 EPS Designs....................................................................................................... 3-60
 

3.4.5.1 AC/AC External Power Supplies........................................................... 3-61
 

3.4.5.2 Unregulated Line-Frequency AC/DC External Power Supplies ........... 3-62
 

3.4.5.3 Linear-Regulated Line-Frequency AC/DC External Power Supplies ... 3-62
 

3.4.5.4 Switching-Regulated Line-Frequency AC/DC External Power Supplies . 3­

65
 

3.4.5.5 Switched-Mode AC/DC External Power Supplies ................................ 3-66
 

3.4.6 EPS Technology Options................................................................................... 3-69
 

3.4.7 BC Modes of Operation..................................................................................... 3-70
 

3.4.7.1 Active or Charge Mode.......................................................................... 3-70
 

3.4.7.2 Maintenance Mode................................................................................. 3-70
 

3.4.7.3 Standby or No-Battery Mode................................................................. 3-70
 

3.4.7.4 Other Modes and Applicability.............................................................. 3-71
 

3.4.8 BC Efficiency Metrics ....................................................................................... 3-71
 

3.4.9 Battery Charger Design...................................................................................... 3-72
 

3.4.10 Battery Charger Technology Options ................................................................ 3-74
 

REFERENCES .......................................................................................................................... 3-77
 

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LIST OF TABLES
 

TABLE 3.1 SHIPMENTS BY APPLICATION, THOUSANDS ............................................... 3-9
 

TABLE 3.2 ANNUAL TELEPHONE UNIT SHIPMENTS (THOUSANDS) AND CAGR ... 3-15
 

TABLE 3.3 EXTERNAL POWER SUPPLY LIFETIMES AND SHIPMENTS BY PRODUCT 

CLASS ........................................................................................................................... 3-29
 

TABLE 3.4 EPS PRODUCT CLASS A1A: TOP APPLICATIONS, SHIPMENTS, AND 

TABLE 3.5 EPS PRODUCT CLASS A1B: TOP APPLICATIONS, SHIPMENTS, AND 

TABLE 3.6 EPS PRODUCT CLASS A1C: TOP APPLICATIONS, SHIPMENTS, AND 

TABLE 3.7 EPS PRODUCT CLASS A1D: TOP APPLICATIONS, SHIPMENTS, AND 

TABLE 3.8 EPS PRODUCT CLASS A2: TOP APPLICATIONS, SHIPMENTS, AND 

TABLE 3.9 EPS PRODUCT CLASS A3: TOP APPLICATIONS, SHIPMENTS, AND 

TABLE 3.10 EPS PRODUCT CLASS A4: TOP APPLICATIONS, SHIPMENTS, AND
 

TABLE 3.11 EPS PRODUCT CLASS X1: TOP APPLICATIONS, SHIPMENTS, AND 

TABLE 3.12 EPS PRODUCT CLASS X2: TOP APPLICATIONS, SHIPMENTS, AND 

TABLE 3.13 EPS PRODUCT CLASS H1: TOP APPLICATIONS, SHIPMENTS, AND 

TABLE 3.14 EPS PRODUCT CLASS M1: TOP APPLICATIONS, SHIPMENTS, AND 

TABLE 3.15 EPS PRODUCT CLASS M2: TOP APPLICATIONS, SHIPMENTS, AND 

TABLE 3.16 EPS PRODUCT CLASS M3: TOP APPLICATIONS, SHIPMENTS, AND 

TABLE 3.17 EPS PRODUCT CLASS M4: TOP APPLICATIONS, SHIPMENTS, AND 

TABLE 3.18 EPS PRODUCT CLASS B1: TOP APPLICATIONS, SHIPMENTS, AND 

TABLE 3.19 EPS PRODUCT CLASS B2: TOP APPLICATIONS, SHIPMENTS, AND 

TABLE 3.20 EPS PRODUCT CLASS B3: TOP APPLICATIONS, SHIPMENTS, AND 

TABLE 3.21 EPS PRODUCT CLASS B4: TOP APPLICATIONS, SHIPMENTS, AND 

LIFETIMES ................................................................................................................... 3-30
 

LIFETIMES ................................................................................................................... 3-30
 

LIFETIMES ................................................................................................................... 3-31
 

LIFETIMES ................................................................................................................... 3-31
 

LIFETIMES ................................................................................................................... 3-31
 

LIFETIMES ................................................................................................................... 3-32
 

LIFETIMES ................................................................................................................... 3-32
 

LIFETIMES ................................................................................................................... 3-32
 

LIFETIMES ................................................................................................................... 3-32
 

LIFETIMES ................................................................................................................... 3-32
 

LIFETIMES ................................................................................................................... 3-33
 

LIFETIMES ................................................................................................................... 3-33
 

LIFETIMES ................................................................................................................... 3-33
 

LIFETIMES ................................................................................................................... 3-33
 

LIFETIMES ................................................................................................................... 3-34
 

LIFETIMES ................................................................................................................... 3-34
 

LIFETIMES ................................................................................................................... 3-34
 

LIFETIMES ................................................................................................................... 3-34
 

TABLE 3.22 ENERGY PERFORMANCE OF NEW EXTERNAL POWER SUPPLIES IN 2009
 

........................................................................................................................................ 3-35
 

TABLE 3.23 ENERGY PERFORMANCE OF EXTERNAL POWER SUPPLIES IN 2007 .. 3-36
 

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TABLE 3.24 BATTERY CHARGER LIFETIMES AND SHIPMENTS BY PRODUCT CLASS
 

........................................................................................................................................ 3-36
 

TABLE 3.25 BC PRODUCT CLASS 1: TOP APPLICATIONS, SHIPMENTS, AND 

LIFETIMES ................................................................................................................... 3-37
 

TABLE 3.26 BC PRODUCT CLASS 2: TOP APPLICATIONS, SHIPMENTS, AND 

LIFETIMES ................................................................................................................... 3-37
 

TABLE 3.27 BC PRODUCT CLASS 3: TOP APPLICATIONS, SHIPMENTS, AND 

LIFETIMES ................................................................................................................... 3-37
 

TABLE 3.28 BC PRODUCT CLASS 4: TOP APPLICATIONS, SHIPMENTS, AND 

LIFETIMES ................................................................................................................... 3-38
 

TABLE 3.29 BC PRODUCT CLASS 5: TOP APPLICATIONS, SHIPMENTS, AND 

LIFETIMES ................................................................................................................... 3-38
 

TABLE 3.30 BC PRODUCT CLASS 6: TOP APPLICATIONS, SHIPMENTS, AND 

LIFETIMES ................................................................................................................... 3-38
 

TABLE 3.31 BC PRODUCT CLASS 7: TOP APPLICATIONS, SHIPMENTS, AND 

LIFETIMES ................................................................................................................... 3-38
 

TABLE 3.32 BC PRODUCT CLASS 8: TOP APPLICATIONS, SHIPMENTS, AND 

LIFETIMES ................................................................................................................... 3-39
 

TABLE 3.33 BC PRODUCT CLASS 9: TOP APPLICATIONS, SHIPMENTS, AND 

LIFETIMES ................................................................................................................... 3-39
 

TABLE 3.34 BC PRODUCT CLASS 10: TOP APPLICATIONS, SHIPMENTS, AND 

LIFETIMES ................................................................................................................... 3-39
 

TABLE 3.35 ENERGY PERFORMANCE OF NEW BATTERY CHARGERS IN 2009....... 3-40
 

TABLE 3.36 BC AND EPS EFFICIENCY PROGRAMS WORLDWIDE.............................. 3-42
 

TABLE 3.37 TRADE ASSOCIATIONS .................................................................................. 3-47
 

TABLE 3.38 COMPARISON OF I2 × R LOSSES FOR TWO 20-WATT EPSS .................... 3-51
 

TABLE 3.40 PROPOSED CLASS A EPS PRODUCT CLASSES. ......................................... 3-53
 

TABLE 3.41 PROPOSED MULTIPLE VOLTAGE EPS PRODUCT CLASSES................... 3-53
 

TABLE 3.42 PROPOSED HIGH POWER EPS PRODUCT CLASSES.................................. 3-53
 

TABLE 3.43 PROPOSED MEDICAL EPS PRODUCT CLASSES. ....................................... 3-54
 

TABLE 3.44 PROPOSED MADB EPS PRODUCT CLASSES. ............................................. 3-54
 

TABLE 3.45 BC PRODUCT CLASSES USED IN THE PRELIMINARY ANALYSIS. ....... 3-58
 

LIST OF FIGURES 

FIGURE 3.1 EXAMPLE OF A WALL ADAPTER AND A DESKTOP ADAPTER, TREATED 

TOGETHER AS ―WALL ADAPTERS‖......................................................................... 3-2
 

FIGURE 3.4 PATHS OF DISTRIBUTION FOR BATTERY CHARGERS AND EXTERNAL
 

FIGURE 3.6 THE EISA STANDARD AND ENERGY STAR 2.0 SPECIFICATION FOR 

FIGURE 3.7 THE EISA STANDARD AND ENERGY STAR 2.0 SPECIFICATION FOR NOFIGURE 3.2 EXAMPLE OF A CRADLE AND A CHARGING BASE ................................... 3-3
 

FIGURE 3.3 EXAMPLES OF BATTERIES .............................................................................. 3-3
 

POWER SUPPLIES....................................................................................................... 3-44
 

FIGURE 3.5 TOP EPS MANUFACTURERS IN 2005 ............................................................ 3-46
 

AVERAGE EFFICIENCY ............................................................................................ 3-50
 

LOAD POWER CONSUMPTION................................................................................ 3-50
 

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FIGURE 3-8 EPSS QUALIFYING FOR ENERGY STAR 2.0 AS OF SEPTEMBER 2009. . 3-52
 

FIGURE 3.9 EXAMPLE OF AN EFFICIENCY CURVE OF AN EPS IN ACTIVE MODE . 3-59
 

FIGURE 3.10 CIRCUIT DIAGRAM FOR AN AC/AC EXTERNAL POWER SUPPLY 

FIGURE 3.14 BLOCK DIAGRAM OF A SWITCHING-REGULATED LINE-FREQUENCY 

...... 3-61
 

FIGURE 3.11 CIRCUIT DIAGRAM OF A LINE-FREQUENCY RAW SUPPLY ................ 3-62
 

FIGURE 3.12 BLOCK DIAGRAM OF A LINEAR REGULATOR........................................ 3-64
 

FIGURE 3.13 SIMPLIFIED CIRCUIT DIAGRAM OF A LINEAR REGULATOR .............. 3-64
 

AC/DC EPS ................................................................................................................... 3-66
 

FIGURE 3.15 BLOCK DIAGRAM OF A SWITCHED-MODE POWER SUPPLY............... 3-67
 

FIGURE 3.16 SIMPLIFIED CIRCUIT DIAGRAM OF A FLYBACK SWITCHING
 

REGULATOR ............................................................................................................... 3-68
 

FIGURE 3.17 GENERAL SCHEMATIC OF A BC AND BATTERY.................................... 3-72
 

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CHAPTER 3. MARKET AND TECHNOLOGY ASSESSMENT
 

3.1 INTRODUCTION 

3.1.1 Definitions and Nomenclature 

A key issue in DOE’s BC and EPS rulemakings is the necessity for clear and distinct 

product definitions. DOE has taken several approaches in the past, but with the current 

rulemakings, the need for regulatory definitions based on an interpretation of the EPCA statutory 

language is becoming more pressing. Therefore, before discussing any analysis, DOE will 

review the current statutory definitions and discuss the possible interpretation of these 

definitions, with the goal of establishing regulatory definitions that provide greater clarity for 

interested parties. 

3.1.1.1 Current Statutory Definitions 

Title III of EPCA (42 U.S.C. 6291, et seq.) sets forth a variety of provisions designed to 

improve energy efficiency. Part A of Title III (42 U.S.C. 6291–6309) establishes the ―Energy 

Conservation Program for Consumer Products Other Than Automobiles.‖ Section 135 of EPACT 

2005, Pub. L. 109-58, amended sections 321 and 325 of EPCA, inserting definitions for BCs and 

EPSs into the list of covered products. Subsequently, Section 301 of EISA created a subset of 

EPSs designated as Class A. Chapter 2 of this preliminary TSD presents the statutory definitions 

for: 

Battery Charger 

External Power Supply 

Class A External Power Supply 

Consumer Product 

Detachable Battery 

3.1.1.2 Additional Definitions 

DOE developed additional definitions to clarify ambiguous terms in the rulemaking. 

Specifically, determining which parts of a battery charging system are considered the battery 

charger (BC), and therefore subject to this standards rulemaking, depends on the interpretation of 

the BC definition, just as which wall adapters are considered EPSs depends on the interpretation 

of the EPS definition. In other words, ―BC‖ and ―EPS‖ are regulatory terms subject to 

interpretation, while ―battery charging system‖ and ―wall adapter‖ are terms that describe 

physical objects. Throughout the preliminary analysis, DOE has taken care to distinguish 

between these regulatory and physical terms, defined as follows. 

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Wall Adapter 

DOE uses the term ―wall adapter‖ to refer to any external power adapter (Figure 3.1) that 

connects a consumer product to the household electric supply (AC mains), regardless of whether 

the device contains charge control circuitry. Wall adapters, which consist of a power conversion 

circuit housed in a plastic enclosure and typically connected to a product through an output cord, 

provide many functions, the most important of which is safety. All wall adapters isolate the 

consumer product from mains and reduce the voltage, thereby reducing the risk of shock. 

In addition to performing isolation and conversion functions, wall adapters may also 

provide functions such as rectification (AC/DC conversion), voltage regulation, and/or control of 

the charge current from AC mains to the battery for safe charging. There are no distinguishing 

physical features (e.g., size, shape, etc.) that would definitively allow an observer to determine 

the internal circuitry (and the corresponding functions) of a wall adapter, although certain 

physical features have been used in other programs. Furthermore, some adapters can provide 

different functions depending on their region of operation—i.e., the output current and voltage at 

a particular time. Appendix 3C presents an analysis of criteria that could be used to determine 

the presence of charge control in a wall adapter. 

Wall Adapter Desktop Adapter 

Figure 3.1 Example of a Wall Adapter and a Desktop Adapter, Treated Together as “Wall 

Adapters” 

Cradle or Charging Base 

For many rechargeable consumer products, the battery may be charged using a ―cradle‖ 

or ―charging base‖ (Figure 2.2). Some cradles and charging bases use a wall adapter in tandem, 

while others perform the same power conversion and isolation functions, rendering wall adapters 

unnecessary. Similar to wall adapters, cradles and charging bases have no distinguishing physical 

features that would allow an observer to conclusively determine their internal circuitry and 

function. 

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Handheld vacuum cleaner cradle Power tool battery charging base 

(shown with wall adapter) (no wall adapter) 

Figure 3.2 Example of a Cradle and a Charging Base 

Battery 

For this rulemaking, DOE considers ―batteries‖ to be one or more sealed electrochemical 

cells that provide power to a consumer product, allowing it to operate while disconnected from 

AC mains. Products may use batteries in standard-size (e.g., AA, AAA, etc.) packages or nonstandard, product-specific packages. Batteries may also be packaged with additional circuitry to 

prevent overcharging, or to detect faults or charge status. Examples of batteries are illustrated in 

Figure 3.3. 

Standard-size batteries Laptop battery 

pack 

Power tool battery pack 

shown with sub-C cell (not to scale) 

Figure 3.3 Examples of Batteries 

Battery Charging System 

The term ―battery charging system‖ refers to all the components necessary to charge and 

maintain a battery, from the AC wall plug to the battery itself, and includes the wall adapter, 

cradle, and—if the battery is integral to the consumer product—the product itself. 

3.1.2 Test Procedures 

Section 323 of EPCA (42 U.S.C. 6293) sets forth generally applicable criteria and 

procedures for DOE’s adoption and amendment of test procedures, which manufacturers of 

covered products must use to certify to the U.S. Department of Energy (DOE) that their products 

comply with EPCA energy conservation standards and to quantify the efficiency of their 

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products. Also, these test procedures must be used whenever testing is required in an 

enforcement action to determine whether covered products comply with EPCA standards. 

DOE has adopted test procedures for both BCs and EPSs. These are described in turn in 

the sections below, while further discussion of testing and efficiency metrics and their 

application to the analysis of achievable performance can be found later sections 3.4.3 for EPSs 

and 3.4.8 for BCs. 

Within this document, the term ―energy consumption‖ is used loosely to refer to power 

dissipation of BCs and EPSs in one of their several modes, taking into account the time spent in 

that mode. Likewise, while ―efficiency‖ has a precise definition,a it can also refer more generally 

to the energy consumption of a BC or EPS in any of their modes when compared to similar 

devices. Thus devices with lower energy consumption are referred to as more efficient, and vice 

versa throughout this discussion. 

3.1.2.1 EPS Test Procedures 

On December 8, 2006, DOE codified a test procedure final rule for EPSs in appendix Z to 

subpart B of 10 CFR Part 430 (―Uniform Test Method for Measuring the Energy Consumption 

of External Power Supplies‖). 71 FR 71340. DOE’s test procedure, based on the ENERGY 

STAR EPS test procedure, measures active mode efficiency and no-load mode (standby mode) 

power consumption. In the standby and off mode test procedure NOPR for BCs and EPSs, 73 FR 

48054 (August 15, 2008), DOE proposed to amend the EPS test procedure to add a measurement 

of power consumption in off mode, where, if the EPS has an on-off switch, the EPS is connected 

only to mains and the switch is turned off. These amendments were included in the final rule, 

published March 27, 2009. 74 FR 13335. DOE is considering amending the EPS test procedure 

as part of its revision to the BC test procedure NOPR published on April 2, 2010. 75 FR 16958. 

Active mode conversion efficiency is the ratio of output power to input power. DOE 

averages the efficiency at four loading conditions—25, 50, 75, and 100 percent of maximum 

rated output current—to assess the performance of an EPS. DOE also measures the power 

consumption of the EPS when disconnected from the consumer product, which is termed no-load 

power consumption. If the EPS has an on-off switch, the switch is on when conducting the 

measurement. 

3.1.2.2 BC Test Procedures 

On December 8, 2006, DOE adopted a test method to measure the efficiency of battery 

chargers. 71 FR 71340. This test method, based on the U.S. Environmental Protection Agency’s 

(EPA) ENERGY STAR ―Test Methodology for Determining the Energy Performance of Battery 

Charging Systems,‖ measures the power consumed by BCs in maintenance and no-battery, as 

well as the energy recovered from the battery during discharge, calculating an energy ratio. 

In the December 8, 2006, Test Procedure Final Rule, DOE stated that it intended to study 

further BC active mode energy consumption and reserved a section in the test procedure (section 

a See, for instance, section 4.3.1 of IEEE standard 1515 or the CEC single-voltage EPS test procedure, incorporated 

by reference into DOE’s single-voltage EPS test procedure in appendix Z. 

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4(b) of appendix Y to subpart B of 10 CFR Part 430). 71 FR 71340, 71360. During the 

framework document public meeting, DOE presented several potential approaches to measuring 

battery charger energy consumption in active mode. Numerous interested parties submitted 

comments on active mode measurement in general, and specifically on these sub-issues: 

Harmonization of DOE’s BC active mode test procedure with the BC test procedure 

adopted by the California Energy Commission (CEC) 

Limiting testing to U.S. line-voltage AC input (115 volts at 60 hertz) 

Shortening the charge and maintenance mode testing period to less than 24 hours 

Incorporating usage profiles into the test procedure 

Measuring charger output energy instead of battery output energy 

Measurements at alternative depths-of-discharge to better reflect consumer use 

Test procedure rulemaking schedule 

Appropriate voltage for testing multiple-voltage BCs 

Power factor measurement 

DOE took the comments on the above topics under advisement when developing 

amendments to its existing BC test procedure to accommodate energy consumption in active 

mode. Comments relevant to the proposal, as well as the proposed amendments themselves, are 

discussed in depth in the BC active mode test procedure NOPR, published on April 2, 2010. 75 

FR 16958. 

If adopted, this proposed amendment would stop use of the non-active energy ratio in 

favor of metrics related to energy consumption in each of the energy-consuming modes of 

operation of a BC. As described above, these include active, maintenance, standby, and off 

modes; thus, the test procedure would return four separate metrics. How these four modespecific metrics would be combined for the purpose of an energy conservation standard is 

discussed further in chapter 5. 

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3.2 MARKET ASSESSMENT 

3.2.1 Applications that Use BCs and EPSs 

To characterize the market for BCs and EPSs, DOE gathered information on the products 

that use them. DOE refers to these products as end-use consumer products or BC and EPS 

―applications.‖ This method was chosen for two reasons. First, the demand for applications 

drives the demand for BCs and EPSs because BCs and EPSs are nearly always integrated into, 

bundled with, or otherwise intended to be used with a given application. Second, because most 

BCs and EPSs are not stand-alone products, their usage profiles, energy consumption, and power 

requirements are all determined by the associated application. Therefore, to develop reliable 

estimates of the real-world unit energy consumption of a BC or EPS, it is necessary to examine 

the application. 

DOE began the development of the preliminary analysis by analyzing online and brickand-mortar retail outlets to determine which applications use BCs and EPSs and which BC and 

EPS technologies are most prevalent. Non-Class A EPSs were analyzed as part of the non-Class 

A EPS determination analysis, which was completed shortly before this market survey. NonClass A EPSs were, therefore, not addressed in this market survey; however, DOE will 

incorporate them into an updated market survey at the NOPR stage of the standards rulemaking. 

To best characterize the markets for BCs and EPSs, DOE focused its search on those applications 

likely to have the greatest significance in the standards analyses (based on shipments, lifetimes, 

and energy use). The survey consisted of the following steps: 

1.	 Identified all applications that use BCs and Class A EPSs 

2.	 Estimated annual shipments, lifetimes, and energy consumption for those applications. 

3.	 Selected applications likely to have a significant impact on energy use based on estimated 

shipments, lifetimes, and energy consumption. 

4.	 For selected applications, visited websites and retail outlets to identify popular models 

and document BC and EPS characteristics. 

DOE then used this survey to select representative units and common BCs and EPSs to 

be tested. This process is described in chapter 5. The results of this product survey are presented 

in the Excel file BCEPS_Master_Survey.xls. 

DOE has identified four major trends that can affect shipments of BCs and EPSs over 

time. These trends are all related to the consumer products powered by BCs and EPSs. 

Demand for Consumer Product Applications refers to the changes in preferences, 

level of affluence, and population size that affect the demand for existing consumer 

product applications that use BCs or EPSs. 

Convergence means the application that uses an EPS is made redundant by another 

application. For example, mobile telephones increasingly incorporate the features of 

personal digital assistants (PDAs), digital cameras, portable media players, and 

portable navigation devices. As a result of convergence, some consumers may now 

have fewer devices than in the past, thus reducing the demand for BCs or EPSs. 

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Emergence refers to the creation of new consumer product application categories—a 

critical factor, given the rapid pace of change in the consumer electronics market. 

Substitution means a shift between methods for supplying power to consumer 

products—internal power supplies, external power supplies, primary batteries, 

rechargeable batteries, Universal Serial Bus (USB) systems, and others. 

DOE identified approximately eighty applications that use BCs and EPSs. Although there 

are certainly some BC and EPS applications that DOE did not consider, DOE believes it has 

captured the vast majority of BC and EPS shipments for use with consumer products. Because 

DOE’s scope does not include BCs and EPSs used only in a commercial setting, DOE did not 

estimate shipments of BCs and EPSs used with commercial products. For further discussion of 

the scope of the BCs and EPSs covered in the preliminary analysis, please refer to chapter 2. 

For ease of exposition, DOE grouped applications into nine categories. A categorized list 

of applications is shown in Appendix 3A. For each category, the market assessment examines 

major applications, shipments, lifetimes, and BC and EPS technical characteristics. Trends and 

factors that may affect future shipments of BCs and EPSs are also discussed. Generally, 

characteristics about the batteries, BCs, and EPSs used with each application were derived from 

an extensive survey of products available at online retailers and in stores. DOE surveyed nearly 

1,000 products to gather specific BC and EPS data (such as output voltage). The details of the 

survey can be found in the Excel file BCEPS_Master_Survey.xls. 

3.2.1.1 Audio 

The audio equipment category includes both niche applications, such as guitar effects 

pedals, and very common applications such as MP3 players. This category does not include 

computer speakers. DOE estimates total shipments were 66 million in 2008. The most numerous 

units include MP3 players, MP3 speaker docks, and clock radios; approximately 62 million units 

shipped in 2008.1 DOE estimates that 20 percent of units use an EPS and 73 percent use a BC. 

The prevalence of BC- or EPS-powered musical instruments and component audio equipment is 

low; DOE estimates total BC shipments within these products to be less than 250,000 units and 

EPS shipments to be approximately two million. DOE examined amateur radios as part of its 

determination for non-Class A EPSs. DOE estimated annual shipments of 3,000 high power 

EPSs for amateur radios. These EPSs typically have nameplate output powers of 345 watts. 74 

FR 56928. 

Audio 

Component Audio 

Amateur Radios 

Pre-Amps 

Wireless Speakers 

Musical 

Instruments 

Guitar Effects Pedals 

Keyboards 

Portable Audio & 

Accessories 

MP3 Speaker Docks 

Clock Radios 

MP3 Players 

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MP3 Players 

Portable media players such as MP3 players constitute the majority of shipments in the 

audio category; 43.7 million units were shipped in 2008.1 The vast majority of these units 

employ a BC. While shipments are high, CEA noted an 8.9 percent drop in shipments between 

2007 and 2008. They attribute this decline to convergence with smart phones. In contrast, trends 

to add additional features to portable media players, such as video, could increase demand for 

these devices. CEA expects MP3 player market saturation to increase from 51 percent of 

households in 2009 to 60 percent by 2012. The Pacific Gas and Electric Company and others 

commented that lifetimes are estimated to be four years. (PG&E et al., No. 20 at p. 10) All 

portable media players analyzed by DOE were powered by 3.7 volt batteries. Apple is the market 

leader for portable media players with over 70 percent market share in 2007.2 b Battery energy 

for Apple products ranges from 0.9 to 3.3 watt-hours. Overall, portable media players with color 

display screens tend to use similar batteries as mobile phones. Nearly all portable media players 

are recharged via USB connections, although many manufacturers offer EPSs that output voltage 

at USB levels (five volts) as an optional accessory. DOE assumes that ten percent users that 

purchase an MP3 player also purchase an aftermarket EPS. 

MP3 Speaker Docks and Clock Radios 

From researching common units for sale, DOE found that the majority of MP3 speaker 

docks employ EPSs, while most traditional clock radios run directly from mains power. 

However, convergence between these devices is increasing. In 2008, a total of 17.9 million clock 

radios and MP3 speaker docks were shipped, and DOE estimates approximately 44 percent of 

those units had EPSs.1 Of the models DOE examined, most used EPSs with nameplate output 

power between 13 and 18 watts. DOE found a few models with EPSs as high as 60 watts of 

output power. EPS output voltage clustered around 10, 12, and 15 volts.c DOE estimates that 15 

percent of MP3 speaker docks contain integral rechargeable batteries and have BCs for those 

batteries. DOE found battery information for only one such MP3 speaker dock. That model used 

a 3.7 volt battery rated at 8 watt hours. Since most MP3 speaker docks can also charge the media 

player, there is some question as to whether these docks contain BCs for this purpose. At present, 

DOE believes that charge control lies within the media player while the MP3 speaker dock acts 

simply as a power supply. DOE welcomes stakeholder comment on this issue. DOE assumes 

lifetimes for MP3 speaker docks and clock radios to be 4 years. 

Wireless Speakers 

DOE estimates shipments of wireless speakers to be 750,000 units in 2008. This 

application will likely experience strong growth as wireless technology improves and demand 

increases. Wireless speakers require no cable to transmit audio output from the audio source, but 

the wireless transmitter is powered by an EPS. Power to the speaker or speakers is provided by 

one or two EPSs and DOE estimates that 1.5 million EPSs were shipped with wireless speakers 

in 2008. DOE is aware of one wireless speaker model that is powered by a wall adapter and can 

charge and operate on standard-sized C-cell rechargeable batteries.3 

b According to the NPD Group, the iPod’s market share was at 72.7 percent in January, 72.3 percent in February,
 

and 68.9 percent in March.
 c Based on wall adapter information from 20 MP3 speaker docks and clock radios.
 

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3.2.1.2 Computers and Peripherals 

This category includes all computers and related equipment. As this is a broad category, 

applications have been separated into five subcategories: computers, desktop accessories, 

document manipulation, document readers, and networking. These applications have lifetimes of 

between 3 and 5 years. (PG&E et al., No. 20 at p. 10)4 

Computers and Peripherals 

Computers 

Personal Digital Assistants 

Netbooks 

Notebooks 

Desktop 

Accessories 

LED Monitors 

Computer Speakers 

External Hard Drives 

Uninterruptible Power Supplies 

Document 

Manipulation 

Image Scanners 

Handheld Image Scanners 

Inkjet Imaging Equipment 

Portable Printers 

Document Reader E-Book Readers 

Networking LAN Equipment 

Wi-Fi Access Points 

Shipments totaled 118.6 million units in 2008 for the category as a whole. DOE estimates that 

53.7 million BCs and nearly 88.7 million EPSs were shipped with these end-use products. DOE 

estimated external hard drive shipments at over 600,000 units in 2008. Document manipulation 

devices shipped 25.6 million units. Electronic book readers were the smallest subcategory in 

terms of shipments, with 580,000 units shipped in 2008, though this segment is growing rapidly.1 

Computers 

BC/EPS shipments in the computers subcategory are high. For computers alone 

(including notebooks, netbooks, and personal digital assistants (PDAs)), shipments were 

approximately 46 million units in 2008.5 Applications covered in the computers subcategory are 

built for portability and, as a result, use BCs and EPSs. PDAs have seen significant convergence 

with mobile phones. In 2005, more than 4.7 million units were shipped, and that number 

decreased to two million in 2008.1 The functionality of smart phones reduces the need for two 

devices and, by extension, the need for multiple BCs. See Table 3.1 for an illustration of this 

convergence. DOE includes smart phones in its analysis of mobile phones under the telephony 

category. 

Table 3.1 Shipments by Application, thousands 

2005 2006 2007 2008 CAGR (%) 

PDAs 4,720 3,850 2,175 1,977 -25 

Smart 

Phones 

9,842 14,020 24,196 39,884 59 

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Based on its survey of the market, DOE found that all EPSs powering notebook and 

netbook computers are similar in voltage (~20 V), but vary in output power due to differences in 

intended functionality. Netbooks require wall adapter output powers of approximately 30-65 W, 

while notebooks require 60-120 W. Both types typically use 11.1 V batteries. Battery energy is 

similar between netbooks and notebooks, typically ranging from 40 to 60 watt hours. Due to 

their smaller product and battery sizes, PDAs use wall adapters rated at outputs of 5 V to power 

the device and/or recharge the devices’ 3.7 volt batteries. Although PDA shipments are in 

decline, netbook shipments have grown significantly owing to their greater portability and lower 

prices compared to full-sized notebooks.5 

Desktop Accessories 

Desktop accessories are applications designed for at-home use with personal computers. 

Total shipments in 2008 were 17.8 million units and include computer speakers, external hard 

drives, and uninterruptible power supplies. Without data on computer speaker shipments, DOE 

assumed that speaker sales would be equivalent to sales of desktop computers, at 10.2 million 

units in 2008.1 Based on its survey of products, DOE estimates that 38 percent of computer 

speakers are powered by EPSs. Output power for these EPSs varied between 6 and 68 W. DOE 

6,7,d estimates that 58 percent of external hard drives, 374,000 units, used EPSs. Most units used 

12 V EPSs with output power that varied between 12 and 57 W. 

Uninterruptable power supplies (UPSs) contain BCs but do not use EPSs. UPSs act as 

power strips with built-in batteries that remain charged in order to provide battery power to 

attached devices in the event of a power surge or power interruption. Based on total revenue 

from a report by Global Industry Analysts, DOE estimated annual sales of consumer UPSs by 

examining the prevalence of UPSs at different capacity ratings available from online retailers. 

DOE estimates annual shipments of consumer UPSs to be 6.9 million units.8 Most consumer 

UPSs contain built-in 12 V batteries with energies ranging from 84 to 168 watt hours. Built-in 

BCs are able to fully charge these batteries in 3 to 24 hours, though most can do so in between 

4.5 and 16 hours. 

DOE also identified an LED monitor that uses a 250 watt EPS, just meeting the Class A 

definition. DOE estimates shipments were 160,000 units in 2008. It is possible that shipments of 

high power non-class A EPSs will increase if future LED monitors move beyond 250 watts of 

nameplate output power. 

Document Manipulation 

Document manipulation is another subcategory containing applications that are 

experiencing significant convergence. DOE estimates total shipments in this subcategory to be 

25.6 million units. Inkjet printers and multi-function devices (MFDs) make up the vast majority 

of devices, at 23.3 million units.9 MFDs are inkjet printers that incorporate scanning, copying, 

and faxing capabilities. The increase in the number of affordable MFD models has significantly 

d Worldwide shipments for external hard drives were 2.6 million in 2006. Based on the Darnell Group’s estimated 

distribution of computer shipments, North America makes up 29 percent of worldwide computer shipments. U.S. 

GDP is 85 percent of North American GDP, yielding U.S. external hard drive shipments of 644,215. DOE estimates 

that 58 percent of external hard drives use power supplies, resulting in EPS shipments of 373,644. 

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reduced the need for several distinct devices. Based on units available in the market, DOE found 

that two major manufacturers, Hewlett Packard and Lexmark, make MFDs and inkjet printers 

10,11 with EPSs, and DOE estimates they have a combined market share of 40 percent. Hence, 

DOE estimates that 9.3 million used EPSs. Output power for most MFDs and printers varies 

significantly within the range of 15-108 W, with most models ranging between 25 and 80 watts. 

Output voltage was consistently at 30-32 V. In 2008 many Hewlett Packard MFDs used nonClass A multi-voltage EPSs. DOE estimates that 3.8 million non-Class A EPSs were shipped 

with Hewlett Packard MFDs in 2008. 

Document Readers 

Electronic document readers, also known as e-book readers, are a quickly growing 

subcategory. CEA predicted shipments would double between 2008 and 2009 to 1.2 million 

units. These portable rechargeable devices enable users to download and display electronic 

books. DOE surveyed five of these devices, four of which were conclusively found to use wall 

adapters (with outputs of 4.2-10.4 W) to power their BCs. The Amazon Kindle, the original ebook reader, uses a 3.7 V battery with 5.7 watt hours of energy. 

Networking 

As wireless technologies gain market share over traditional modems, market saturation of 

networking equipment will continue to increase. These devices include LAN equipment, 

broadband modems, routers, and Wi-Fi access points. With 2008 shipments of 28.7 million units, 

this is one of the largest subcategories in DOE’s analysis.12 Of the units in this category analyzed 

by DOE, 96 percent use EPSs and all of these provide output voltage between 5 V and 12 V, 

with the majority outputting at the 12 V level. Most units have output powers around 12 watts. 

3.2.1.3 Geospatial Equipment 

The geospatial equipment category is comprised of rechargeable global positioning 

system (GPS) devices, which include handheld and in-vehicle GPS devices. DOE believes that 

in-vehicle GPS units make up the majority of the GPS market, given the rapid year over year 

growth they have experienced. Shipments in 2008 were just under 15.3 million units, a 

significant increase from the 8.8 million units shipped in 20071

. Between 2005 and 2008, the 

compound annual growth rate was 174 percent1

. Since the majority of handheld GPS devices are 

powered by primary batteries, DOE assumes that just 15 percent of the handheld devices sold are 

rechargeable. A wall adapter for charging purposes is either included with the product or sold 

separately. Shipment data is not readily available on handheld GPS units, but DOE estimates that 

150,000 units shipped in 2008 use an EPS and BC. DOE assumes lifetimes for handheld and incar GPS units to be 5 years. 

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Geospatial Equipment 

In-Vehicle GPS 

Handheld GPS 

In-vehicle GPS units are primarily charged by a DC car charger, though many can also be 

charged with an AC-DC wall adapter. DOE assumes battery voltage for in-vehicle GPS units is 

3.7 V with energy between 4 and 8 watt hours. 

Convergence is gradually becoming a factor in this category as the market matures and 

new functions are added to differentiate products and boost sales. Examples include GPS models 

that double as two-way radios and GPS models with built in digital cameras. These features were 

included in only a few of the products surveyed, so DOE does not anticipate these units to impact 

BC and EPS shipments significantly. Many automobile manufacturers offer installed navigation 

systems that have the potential to erode the long-term sales potential of stand-alone models. 

Other substitutes include GPS-enabled smart phones. While these technologies are 

limited by the availability of cellular service signals (in addition to GPS satellite data signals), 

smart phones have the potential to limit GPS sales (for both handheld and in-car units). Due to 

limits in mobile phone GPS functionality, however, DOE does not expect mobile phones to 

completely replace GPS units. Regardless, this is an instance of convergence that could place 

downward pressure on BC shipments. 

3.2.1.4 Telephony 

DOE has separated telephony into two sub-categories with very different power supply 

and usage characteristics. These categories are mobile telephony (including two-way radios, 

mobile/cellular telephones, and accessories for these devices) and stationary telephony 

(including cordless telephones and satellite charging bases, caller ID devices, and voice over 

internet protocol – or VoIP – adapters). 

Telephony 

Mobile 

Bluetooth Headsets 

Consumer Two-Way Radios 

Mobile Phones 

Stationary 

Caller ID Devices 

Cordless Phones 

Answering Machines 

VoIP Adapters 

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Shipments in this category vary widely, from standalone caller ID devices, of which 

460,000 units shipped in 2008, to mobile phones, with shipments of 131.4 million units. Total 

1, 13 unit shipments for applications in this category were 189.8 million units. 

Mobile Telephony 

Applications in the mobile telephony category are small, portable devices designed for 

mobile communication. With the exception of those consumer two-way radios that are powered 

by primary batteries, products in this subcategory use BCs. Mobile phones typically employ 

EPSs, although substitution is a factor as some can also obtain power from USB ports. Bluetooth 

headsets are typically charged with USB connectors or wall adapters. 

Features of mobile phones and personal digital assistants (PDAs) have converged. ―Smart 

phones‖ incorporate the utility of handheld computers into mobile telephones, reducing the need 

for two separate devices. CEA predicts that smart phones have the potential to adversely affect 

sales of MP3 players, digital cameras, camcorders, handheld PCs, portable videogames, and GPS 

devices, just as they have nearly eradicated the PDA market.1 For example, it was predicted that 

global sales of GPS-enabled phones would reach 240 million in 200914, while 500 million of the 

mobile phones shipped globally in 2007 were capable of playing digital music15. These 

additional features found in mobile telephones can reduce the demand for other devices that 

share those features and by extension reduce the demand of the BCs and wall adapters used to 

power those applications. 

For those mobile phones surveyed, DOE found all to use EPSs, while some have the 

ability to be charged by USB or 12 V DC car chargers. EPS power output is low (2.5-5 W) and 

nearly all are five volt output. Mobile phones use 3.7 V batteries with capacities that range from 

3 to 5.6 watt hours. 

Mobile phones have average lifetimes of 2 yearse

. While the mobile phone itself is 

designed to last longer than this, the mobile phone industry is driven by technological innovation 

and trends, two factors that lead consumers to replace phones on a regular basis. Furthermore, 

cell phone service contracts average two years in length; after this point, consumers are 

frequently given the option of purchasing a replacement phone at a significant discount. 

Therefore, in the past DOE considered mobile phone lifetimes to be two years and EPS lifetimes 

to also be two years. However, the ―GSMA Universal Charging Solution‖, described below, will 

increase the lifetime of the EPS. 

GSMA Universal Charging Solution. 

In early 2009, 21 mobile phone operators and manufacturers agreed to work together to 

implement a universal battery charging standard for mobile telephones by 201216. Historically, 

each mobile phone has been manufactured and sold with a unique EPS built specifically for that 

phone and its internal battery. As a result, EPS unit shipments have mirrored mobile phone 

shipments. This standard will eliminate the need for consumers to purchase a new EPS each time 

a new mobile phone is purchased and, as a result, will reduce mobile phone EPS shipments. 

e DOE estimated a mobile phone lifetime of 2 years based on the standard length of time for mobile phone contracts. 

Typically, after 2 years, consumers are able to replace mobile phones with newer models at significant discounts. 

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The Environmental Protection Agency (EPA) estimates that 125 million mobile phones 

(and, by extension, nearly that many EPSs) are discarded annually in the United States17. The 

universal charging agreement will use a micro USB interface and common output voltage so that 

new chargers can work with multiple phones. This will result in a significant reduction in annual 

EPS shipments after 2012, as the need to replace old EPSs when a new phone is purchased will 

be eliminated. DOE forecasts that the number of battery chargers manufactured and sold in the 

global market place (and, by extension, the United States) will be reduced by 50 percent. 

The reduction in EPS shipments will be matched by a corresponding increase in product 

lifetime for EPSs, which DOE estimates will be 4 years. The agreement also includes a no-load 

mode power ceiling of 0.15 W.18 This no-load limit may reduce the energy consumption of 

mobile phone EPSs. These potential impacts are discussed in section 3.2.3 

Stationary Telephony 

The stationary telephony subcategory includes cordless phones/answering machines, 

VoIP adapters, and caller ID devices. All use wall adapters. 

Cordless phones and answering devices are often packaged with multiple handsets (each 

with a BC). A typical cordless phone set consists of a charging base with built-in answering 

machine, a handset, and one or more satellite charging bases, each with its own handset. Each 

charging base plugs into a wall outlet via a wall adapter to charge the batteries of the 

corresponding handset. Hence, a cordless phone set will include between one and five wall 

adapters and charging cradles. DOE estimates total EPS shipments for cordless phones and 

answering devices was 39 million units in 2008.f Most cordless phone EPSs have output power 

between 1.2 and 7.7 W and voltage between six and nine volts. DOE found cordless phone 

batteries were either 2.4 or 3.6 volts and between 2.6 and 5.3 watt hours. Cordless 

phone/answering machines have an average lifetime of 5.3 years.g 

Voice over internet protocol, or VoIP, adapters are powered by EPSs, and 8.8 million 

units in were shipped in 2008.1 VoIP adapters provide telephone service via an internet 

connection. VoIP adapters typically have five or 12 V EPSs with power outputs of 10-14 W. 

DOE assumes that stand-alone caller ID devices use EPSs similar to those used for cordless 

phones. Only 460,000 units shipped in 2008. 1 

The low and decreasing shipments of standalone caller ID devices can be explained by 

convergence with stationary telephones, as many now incorporate caller ID technology. 

One trend that negatively affects stationary telephony, including cordless 

phones/answering machines and caller ID devices, is the decline in homes with landline 

telephone service. With the increase in cellular telephone service indicated by increasing mobile 

phone shipments, many households have opted out of landline telephone service. CEA’s data 

f Based on data provided by the Consumer Electronics Association.
 g Based on the average values of three sources: PG&E et. al. (5 years) (PG&E et al., No. 20 at p. 10); Appliance
 

Magazine (5 years); and FY2005 Preliminary Priority-Setting Summary Report and Actions Proposed (6 years).
 

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show that answering devices and cordless phone unit shipments have decreased by an average 17 

percent annually since 2005. The exception in stationary telephony is the VoIP adapter 

application, shipments of which have increased at a CAGR of 29 percent over four years. Strong 

growth in mobile phone unit sales has offset declines in cordless phone unit sales, leading DOE 

to conclude that, despite these fluctuations, the market for BCs and EPSs has remained largely 

unchanged in this subcategoryh

. 

Table 3.2 Annual Telephone Unit Shipments (thousands) and CAGR 

Application 2005 2006 2007 2008 CAGR (%) 

VoIP 

Adapters 

4,111 5,568 7,451 8,845 29 

Cordless 

Phones/ 

Answering 

Devices 

64,928 56,773 41,905 36,781 -17 

Mobile 

Phones 

93,962 110,754 121,000 131,400 12 

Total 163,001 173,095 170,356 177,026 3 

3.2.1.5 Household 

This category encompasses a wide array of applications, ranging from water softeners to 

digital cameras, and DOE estimates that 95 million of these applications that often use BCs or 

EPSs shipped in 2008. 

h As cordless phone sales declined, manufacturers began to bundle multiple receivers and satellite bases in a 

package. As a result, BC and wall adapter sales for this application are higher than cordless phone package sales. 

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Household 

Childcare Baby Monitors 

Breast Pumps 

Entertainment 

RC Cars (Hobby Grade) 

RC Toys 

Portable Video Game Systems 

Video Game Consoles 

Floorcare 

Handheld Vacuums 

Robotic Vacuums 

Stick Vacuums 

Home Systems 

Electronic Pest Repellents 

Home Security Systems 

Irrigation Timers 

Water Softeners/Purifiers 

Kitchen 

Appliances 

Blenders 

Can Openers 

Mixers 

Photo/Video 

Camcorders 

Digital Cameras 

Digital Picture Frames 

Portable DVD Player 

Other Household 

Air Mattress Pumps 

Aquarium Accessories 

Indoor Fountains 

Flashlights/Lanterns 

Universal Battery Chargers 

Household applications are grouped into seven subcategories based on intended use. 

These subcategories differ significantly from one another in market and technology 

characteristics and are, therefore, discussed individually below. 

Photo/Video 

The photo/video subcategory is comprised of consumer products primarily designed for 

photography, video, and viewing pictures and movies. Applications included in this subcategory 

are digital cameras, consumer camcorders, portable DVD players, and digital photo frames. 

Shipments in the photo/video subcategory were 53.4 million units in 2008, with digital camera 

shipments totaling 33 million.1 2008 shipments for the other applications in this category were 

portable DVD players (8.4 million units12), digital picture frames (7.5 million units in 20081

), 

and camcorders (5.6 million units1

). Digital cameras and camcorders have lifetimes averaging six 

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years and five years respectively, while DOE assumes that portable DVD players have lifetimes 

of four years. 

Growth in this category is driven primarily by growth in digital picture frame shipments, 

which have increased from 1.5 million units in 2006 to 7.5 million units in 20081

. Based on 

inspection of 20 top-selling models, DOE estimates that close to 100 percent of digital picture 

frames ship with EPSs. In the same time period, camcorder shipments increased from 5.3 million 

units to 5.6 million units. 1 Despite slow growth, CEA predicts that low-cost camcorders with 

solid state drives have the potential to boost future sales of this application. Furthermore, these 

units tend to use BCs with USB (five volt) input. The popular Flip Video solid state camcorder, 

made by Cisco, controls 17% of the camcorder market with its inexpensive line of camcorders 

that use USB input to recharge their batteries. 19 DOE assumes 25% of camcorder shipments use 

five volt input BCs. Shipments of digital cameras increased slightly from 32.9 million in 2006 to 

33.2 million in 2008.1 CEA attributes this stagnated growth to a combination of market 

saturation and an encroachment on sales due to convergence with other devices such as mobile 

phones. 

DOE estimates that 41 percent of digital cameras ship with BCs.20 Camcorder and digital 

camera BC shipments have remained constant, while digital picture frames, which are relatively 

new to the market, are rapidly gaining market share, resulting in a net increase of BC/EPS 

shipments in the photo/video category. 

Digital camera BCs typically provide output power at 4.2-8.4 V. They are used to 

recharge batteries that typically have 3.2 to 11.1 watt hours of energy. The majority of 

camcorders DOE surveyed used cradle chargers. DOE was unable to find data on aftermarket 

digital camera wall adapters, but very few digital cameras use wall adapters. DOE identified one 

model that used a wall adapter as part of the battery charging system. DOE is also aware of 

digital cameras that have optional EPSs to power the digital camera without a battery. DOE 

found a few camcorders that had the ability to draw power directly from the wall adapter with or 

without an installed battery. In these cases, the wall adapter functions as an EPS. DOE also noted 

a strong trend towards USB power for camcorders; the best selling model in 2008 was 

rechargeable by this method19. DOE found EPSs for digital picture frames to range between 7.5 

and 24 W of output power. Portable DVD players use wall adapters with output powers between 

9 and 24 W to charge batteries with rated energy between 16 and 32 watt hours. 

It is important to note that many mobile phones and PDAs now include digital camera 

and digital video recording technologies. While DOE expects that this has had a negative effect 

on the subcategory’s shipments, this effect has most likely been small, a result of the relatively 

poor quality of most mobile phone camera lenses and sensors. As mobile phones are equipped 

with higher quality cameras with greater functionality, it is possible that the convergence will 

increase. Portable DVD players may also face the pressures of convergence with other 

applications. As streaming videos become more common and mobile devices (such as mobile 

phones and portable music players) are able to store and play full-length digital movies, the 

market for portable DVD players may decline. If these applications continue to converge, the 

demand for multiple devices will be reduced, thus reducing the demand for BCs. 

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Another instance of convergence within this subcategory is the ability of many digital 

cameras to record good-quality videos. Many compact, ―point and shoot‖ digital cameras can 

shoot videos, while a few recent entrants into the digital single-lens reflex (DSLR) camera 

market can shoot high-definition videos. DOE expects that this convergence has reduced the 

need for consumers to own separate digital cameras and camcorders and, as a result, has reduced 

the need for the BCs and EPSs powering these devices. 

Floor Care 

This subcategory contains three applications: hand vacuums, stick vacuums, and robotic 

vacuums. All three applications include models that utilize battery chargers and wall adapters 

and include models with charging cradles. 

In 2008, vacuum unit shipments were 4.2 million21 for rechargeable handheld models, 

22 21 one million for robotic models (all are cordless, rechargeable models), and 4.2 million for all 

stick vacuums. DOE estimates that 63 percent of stick vacuums (2.6 million) are rechargeable. 

Thus, DOE estimates total BC shipments for floor care were 7.8 million units in 2008. 

All of the handheld rechargeable vacuums surveyed are charged via charging cradles 

coupled with wall adapters. BC and wall adapter specifications for handheld vacuums were not 

readily available; however battery voltage ranged widely from 4.7 to 40 V, with most batteries 

between 9.6 V and 20 V. DOE assumes typical hand vacuums have battery energy of 19 watt 

hours. 

Stick vacuums are designed for cleaning larger floor areas and have higher capacity 

batteries than do handheld vacuums. Approximately 50-60 percent of the rechargeable units 

surveyed were charged via a charging cradle, with the remainder utilizing wall adapters instead. 

DOE expects that, like handheld vacuums, stick vacuums with charging cradles are designed for 

the charger to be plugged into mains all the time. Charging times ranged from 3 to 24 hours, 

while battery voltage ranged between 6 and 24 V. 

The majority of popular robotic vacuums can be charged via a wall adapter and charging 

―base.‖ The base is similar to a cradle in that the product spends the majority of its time plugged 

in. Battery energy is higher for robotic models than for stick or handheld models, as the battery 

must power the vacuum, sensors, and drive wheels. DOE inspected two additional robotic 

products manufactured by iRobot, the largest manufacturer of robotic vacuums: a robotic floor 

washer and a robotic gutter cleaner. Both use batteries of similar size and chemistry to the 

company’s floor vacuum. Charging time for robotic vacuums was between 3 and 15 hours. 

Where data were available, DOE found BC output voltages of 17-22 V and energy between 36 

and 43 watt hours. 

Kitchen Appliances 

Very few kitchen appliances use BCs or EPSs. DOE estimates that only about 400,000 

shipments included BCs and just 20,000 had EPSs. Overall shipments of kitchen appliances are 

significant, however. Appliance Magazine listed 2008 shipments for all electric blenders, can 

openers, and mixers as 1.2, 5.7, and 5.8 million, respectively.21 The May 2009 issue of Appliance 

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Magazine shows that sales of electric handheld blenders, can openers, and mixers have been 

steady since 200521. Conversations with the Association of Home Appliance Manufacturers 

(AHAM) have supported DOE’s assumption that rechargeable units make up small fractions of 

the unit shipments for these applications. 

Childcare 

Baby monitors use BCs and wall adapters, while breast pumps use EPSs but not BCs. 

Other applications considered elsewhere in the analysis are toys and entertainment devices. DOE 

estimates that 2005 shipments of baby monitors were 1.5 million.23 i DOE assumes flat shipments 

between 2005 and 2008 and that all units sold today are rechargeable. Most baby monitors use at 

least two BCs and wall adapters, one for the nursery unit and one for the receiving unit. DOE 

assumes that the average baby monitor is used intermittently over a period of 4 years. DOE does 

not have shipment data for breast pumps, but estimates shipments 300,000 units annually. Breast 

pumps are powered by EPSs. 

Entertainment 

The home entertainment subcategory includes toys, hobby products, and electronics 

specifically designed for at-home recreational purposes. These include video game systems 

(consoles and portable handheld systems), radio controlled toys, and hobby-grade radio 

controlled vehicles. The ride-on toy application is included in the transport category due to 

similarities between BCs for ride-on toys and BCs for other applications in that category. Other 

applications not analyzed in this category include musical instruments, computers, and 

recreational transport (such as motorized bicycles). 

DOE estimates total unit shipments to be 34.5 million. The majority of units are 

videogame systems. Shipments of the two most-popular handheld video game systems, the 

Nintendo DS and Sony PSP, totaled 13.8 million units in 2008, and all use BCs and EPSs.24 

DOE estimates lifetimes of 3 years based on the rate at which manufacturers typically develop 

new systems. EPSs used with handheld game systems are 5 V and have output powers of 2.5 to 

7.5 watts. They are powered by 3.7 V batteries with 1.8 to 4.4 watt hours of energy. 

All of the top three video game consoles—the Nintendo Wii, Microsoft Xbox 360, and 

Sony Playstation3—use EPSs. Industry-wide shipments in 2009 were 18.4 million units.24 

Shipments of the Nintendo Wii and Sony PlayStation 3, which are both powered by Class A 

EPSs, totaled 13.5 million units; an additional 4.9 million non-Class A EPSs shipped with the 

Microsoft Xbox 360, which uses a 198 watt non-Class A EPS that has multiple simultaneous 

output voltages. According to a report published by the Natural Resources Defense Council, this 

represents monthly sales growth of 8 percent over the previous 7 years25. EPS output power 

ranges between 44.4 W and 48 W. 

This category has experienced a form of convergence that may lead to an increase, rather 

than a decrease, in EPS shipments. Most new videogame consoles have the ability to play DVD 

and Blu-ray discs. Stationary DVD and Blu-ray players are not powered by EPSs. This additional 

i Estimate based on shipments of similar baby products. 

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functionality in video game consoles may cause some consumers who may otherwise have 

purchased a stationary DVD or Blu-ray player to purchase a console instead, resulting in 

accelerated console sales growth and more EPS shipments. 

DOE lacks shipments data for radio-controlled (RC) toys and hobby-grade RC vehicles, 

but assumes shipments of RC toys to be 7 million per year (similar to toy ride-on vehicles) and 

250,000 hobby grade RC vehicles. DOE assumes that 30 percent of RC toys are rechargeable. 

Hobby grade RC vehicles belong to a niche market. While some units use internal combustion 

engines, DOE believes that half of the hobby grade RC vehicles on the market are shipped with 

or powered by rechargeable battery packs. DOE estimates total shipments with BCs of both 

categories to be 2.2 million units annually. Growth in BC shipments may result if there is an 

increase in the ratio of rechargeable RC toys to those powered by primary batteries. Both types 

of RC vehicles use cradle BCs and often use 7.2 or 9.6 volt batteries with energy between 7.7 

and 10.8 watt hours. 

Home Systems 

Applications considered under the ―home systems‖ category are designed to be 

continually plugged into household power outlets. These applications operate as background 

systems, adding comfort, security, or safety to homes. Home security systems, electronic pest 

repellents, irrigation timers, and water softeners/purifiers are all included in this category. Many 

use EPSs, and home security systems contain battery chargers. Water softeners/purifiers shipped 

1.2 million units in 2008.26 Shipments data were not readily available for electronic pest 

repellents and irrigation timers, but DOE estimates modest shipments of 800,000 units in 2008. 

PG&E estimates lifetimes for emergency systems, which include home security systems, 

to be 7.3 years. (PG&E et al., No. 20 at p. 10) Given the similarities among applications in this 

category, DOE extended this estimate to the other applications in this category as well. 

Given that 28 percent of homes contain security systems and assuming the lifetime provided by 

PG&E, DOE estimates annual shipments of home security systems to be 4.2 million units. Home 

security systems are comprised of various components that use combinations of rechargeable 

batteries (with integrated chargers) and EPSs as power sources. While there are a few basic 

configurations and do-it-yourself installation kits available, security systems are componentbased and highly customizable. As a result, the number of BCs and EPSs varies from system to 

system. Security system EPSs tend to be AC-AC transformers, though some components are 

powered by AC-DC converters. In the most basic home security systems, a simple, nonrechargeable battery-powered circuit is attached to a door, window, or other point of entry into a 

home. Alarm control boxes that monitor these circuits are often powered by an EPS. An 

integrated AC-DC converter that functions as a BC provides a continual source of power to a 

backup battery so, in the event of a power outage, the security system remains functional. 

Wireless systems can be completely battery powered (with optional after-market wall adapters) 

and may include one or more BCs. As a simplification, DOE assumed one BC and EPS are 

included with each security system. 

Typical output powers for home security system EPSs (the majority of which are AC-AC 

EPSs) are 16 or 24 V. DOE found that most home security system BCs convert AC power to DC 

power in order to charge a security system’s backup batteries. Many of these BCs convert AC 

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current to 6, 12, and/or 24 volt DC current to recharge the batteries.j Standard batteries are 12 V 

sealed lead-acid with 14–84 watt hours of energy. Some battery packs feature other battery 

chemistries, 3.6–7.2 V output, and battery capacities of 1.3–13 Ah. 

Water softeners surveyed used AC-AC EPSs rated at 24-volts and 9.6-18 watts nameplate 

output. DOE found information on one irrigation timer that also had a 24 volt AC/AC EPS rated 

at 18 watts.k Electronic pest repellants are typically powered by primary batteries or from mains. 

Very few models use EPSs, and DOE expects shipments to be very low. BC/EPS data on 

electronic pest repellants was not readily available. 

Other Household 

This subcategory is comprised of consumer applications designed for home use that do 

not readily fall under the other subcategories. BC applications include air mattress pumps, 

rechargeable flashlights, and universal battery chargers. Many of these applications also use wall 

adapters, as do aquarium accessories (air and water pumps) and indoor fountain pumps. 

PG&E estimated annual shipments of universal battery chargers to be 300,000 units and lifetimes 

to be eight years. (PG&E et al., No. 20 at p. 11) BCC research predicts that sales of universal 

battery chargers will continue to increase, driven primarily by an increase in rechargeable battery 

sales27. BC data vary significantly based on the model of universal battery charger and the 

batteries it is intended to charge. Simple models can accommodate only two or four AA 

batteries, while others can charge most standard-size rechargeable primary batteries in various 

combinations and quantities. A typical user may frequently charge four AA batteries; therefore 

these BCs would typically charge batteries of ten watt hours. 

PG&E estimates that 100,000 rechargeable flashlights are sold annually, a small fraction 

of all the flashlights shipped annually. Rechargeable flashlights have expected lifetimes of ten 

years. (PG&E et al., No. 20 at p. 11) 

Aquarium and fountain pumps use AC/AC EPSs. DOE examined the ENERGY STAR 

product list of AC/AC EPSs and found aquarium pump EPSs rated at 9 V and 1.8 watts of output 

power. The American Pet Products Manufacturers’ Association estimates that 15 percent of 

households have fish as pets.28 Assuming each fish owner has an aquarium with a pump and 

given an estimated lifetime of five years, DOE estimates shipments of aquarium pumps to be 3.5 

million units annually. DOE lacks a source for shipments data on indoor fountain pumps but 

assumed annual shipments of one million units. DOE assumes indoor fountain pumps use EPSs 

that are similar to aquarium pumps. DOE expects lifetimes for indoor fountains and air mattress 

l, 29, 30 pumps to be approximately five years . 

3.2.1.6 Outdoor Appliances 

j Based on examination of retailer and distributor Web sites, including www.bassburglaralarms.com and
 

www.homesecuritystore.com.
 k The line of Toro ECXTR Sprinkler Timers uses a 24V, 18 watt AC/AC EPS.
 l Estimate for air mattress pumps and aquarium accessories are based on the lifetime estimate of 5 years for indoor
 

fountains. The EPS for indoor fountains primarily powers the fountain’s pump; the same holds true for the EPSs of 

the other two applications. As a result, DOE assumes all three pump applications to have similar operational 

lifetimes. Indoor fountain lifetimes estimates based on an average of the lifetimes quoted on retailer websites. 

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The market for battery powered, rechargeable outdoor appliances is small compared to its 

gasoline-powered counterparts. DOE has identified three battery-powered outdoor appliance 

applications: weed trimmers, hedge trimmers, and lawn mowers. 

Outdoor Appliances 

Weed Trimmers 

Hedge Trimmers 

Lawn Mowers 

DOE lacks a source of shipments data for cordless weed trimmers and hedge trimmers 

but estimates annual shipments to be 300,000 units. Although 300,000 electric lawn mowers 

shipped in 2008, many of these units are corded. However, DOE believes the prevalence of 

cordless mowers will increase. In fact, an examination of products available at major home 

improvement stores showed the availability of 17 cordless lawn mowers compared to just 11 

corded mowers.m Based on this model count, DOE assumes 61 percent of all outdoor appliances 

use BCs. DOE estimates that, as technologies improve and battery capacity increases (allowing 

the product to be used for longer periods of time), battery powered outdoor appliances could 

experience significant growth. 

Cordless lawn mowers require significant power and long discharge times. Most utilize 

sealed lead-acid batteries and battery energy ranges from 240 to 840 watt hours, with a median 

of 410 watt hours. Battery voltage was significantly higher than other outdoor appliances: most 

electric lawn mowers use 24 V batteries, with some as high as 60 V. Most electric lawn mowers 

have charging times of 12-24 hours. 

Short discharge and long recharge times are limitations of cordless lawn mowers. Thus, 

battery powered mowers are impractical for consumers with larger lawns. DOE expects the 

market share for rechargeable units to increase as technologies improve discharge times and 

charging rates. 

By contrast batteries and battery chargers for cordless weed trimmers and cordless hedge 

trimmers are much smaller. Both products have similar batteries with outputs between 12 V and 

18 V and rated energy of 14 to 31 watt hours. Charging times for these products are relatively 

short: between 1-3 hours. 

3.2.1.7 Personal Care 

The personal care products category includes three subcategories. The hair subcategory 

includes beard and mustache trimmers, hair clippers, and electric shavers. The dental 

m Models of corded and cordless lawn mowers available on the websites of The Home Depot, Lowes, and Sears 

were counted. Sites examined September 29, 2009. 

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subcategory includes rechargeable toothbrushes and rechargeable water jets (also known as oral 

irrigators). These products tend to have shallow depths of discharge and smaller capacity 

rechargeable batteries. DOE believes battery energy for most dental and hair products to be 

approximately 1 watt hour. The medical subcategory includes blood pressure monitors, medical 

nebulizers, portable oxygen concentrators, and sleep apnea machines. These applications use 

non-class A EPSs. 

Personal Care 

Dental 

Toothbrushes 

Water Jets 

Hair 

Beard and Mustache Trimmers 

Hair Clippers 

Shavers 

Medical 

Blood Pressure Monitors 

Medical Nebulizers 

Portable Oxygen Concentrators 

Sleep Apnea Machines 

Unit shipments for applications in the hair subcategory were 24.1 million, divided 

between trimmers (9.4 million), clippers (6.1 million), and shavers (8.7 million, 6.6 million of 

which are rechargeablen, 31, 32). DOE believes the majority of trimmers use primary batteries, 

while the majority of clippers are corded. DOE assumes that 25 percent of trimmers and clippers 

use rechargeable batteries. DOE believes the markets for these products to be at or near 

saturation. As a result, demand is expected to remain constant. Most rechargeable grooming 

devices use a wall adapter, often in combination with a cradle. Although data is limited, DOE 

observed that typical battery energy is between one and four watt hours. During its non-class A 

EPS determination, DOE tested two personal care wall adapters. One was rated at 15 volts and 

6.3 watts, while the other was rated at 3 volts and 0.3 watts of output power. 

DOE currently lacks unit shipment data for oral care appliances, although research 

published by the National Housewares Association indicates that 16 percent of oral care 

appliances sold in the first quarter of 2009 were rechargeable. This is an increase from 15 

33 34 percent in the first quarter of 2008. In 2000 ten million electric toothbrushes were sold. DOE 

estimates the popularity of these toothbrushes has increased and assumes that about one percent 

of the population purchases an electric toothbrush annually, leading to annual sales of 

rechargeable toothbrushes at 4.9 million units. Currently rechargeable models in this subcategory 

tend to be significantly more expensive than those powered by primary batteries. Rechargeable 

oral care products are inductively charged and use cradles with wall adapters. Rechargeable 

toothbrushes use inductively charged batteries. Their batteries are typically 1.2 volts and 

approximately 0.8 watt hours. 

n Rechargeable shaver unit shipment estimates were calculated by multiplying total application shipments by the 

International Housewares Association’s estimate that 76 percent of shavers sold in Q2, 2007 were rechargeable. 

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In its notice of proposed determination for non-Class A EPSs DOE examined medical 

devices designed for in-home use that employ EPSs. 74 FR 56928. Some of these applications, 

including nebulizers, portable oxygen concentrators, and sleep apnea machines also use BCs. 

Blood pressure monitors are used by those who must take frequent readings of their blood 

pressure. Most digital units operate with primary batteries; however, some units are also sold 

with an EPS or offer an optional EPS. DOE estimates typical nameplate output power to be 

around 3 watts. 

Nebulizers administer liquid medication as a mist that can be inhaled into the lungs. They 

are commonly used to treat asthma and chronic obstructive pulmonary disease (COPD). The 

EPSs that provide power to nebulizers tend to have nameplate output power in the range of 10 to 

20 watts. 

Sleep therapy devices include continuous positive airway pressure (CPAP), bi-level 

positive airway pressure (biPAP), automatic positive airway pressure (autoPAP), and similar 

machines used to treat obstructive sleep apnea. Some sleep therapy devices are battery powered, 

some plug directly into mains, and others are powered by EPSs, which typically have nameplate 

output power of approximately 28 to 50 watts. DOE found sleep apnea machines that employ 12 

volt batteries with battery energy of 79.2 watt hours. 

Portable oxygen concentrators absorb nitrogen from the air to provide oxygen to the user 

at higher concentrations, eliminating the need for oxygen tanks. These devices typically use 

EPSs ranging from 90 to 200 watts. Portable oxygen concentrators include batteries and are 

typically sold with BCs for both at-home and in-vehicle use. Therefore, although DOE estimates 

that approximately 58,000 portable oxygen concentrators were sold in 2008, the number of BCs 

shipped with them is twice that. DOE found an example with a 195 watt hour battery. 

3.2.1.8 Power Tools 

The cordless power tool market is large, with 23.4 million units shipped in 2008.12 DOE 

divides power tools into two categories: Do-It-Yourself (DIY) and professional tools. 

Power Tools 

DIY Power Tools (Integral) 

DIY Power Tools (External) 

Professional Power Tools 

DIY tools are aimed at casual users and have batteries of less than 18 volts while 

professional tools have batteries of 18 volts or more. Both types of tools are frequently purchased 

by consumers. 

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DOE estimates that 50 percent of power tools shipped are DIY tools. These can be 

divided into those with detachable batteries and those with integral batteries. DOE assumed that 

the former account for 30 percent and the latter 20 percent of the total market. Based on data 

provided by the Power Tool Institute, DOE estimated that 80 percent of DIY tools with 

detachable batteries and 100 percent of DIY tools with integral batteries use wall adapters. 

Professional power tools use detachable battery packs and the battery charging system does not 

use a wall adapter. Based on manufacturer interviews and data from PG&E, DOE estimates 

average power tool lifetime at 5.9 years for DIY tools and 5.4 years for professional tools. 

(PG&E et al., No. 20 at p. 11) 

According to forecasts from the Darnell Group, the market for cordless rechargeable 

power tools will continue to grow at an average annual rate of 10.6 percent until 2013. This 

growth is attributed to a falling cost for increasingly powerful and flexible tools. DOE believes 

that short-term growth will be tempered by the slowdown in the construction and remodeling 

industries. 

Batteries for DIY tools are quite varied. Smaller tools, such as cordless screw drivers, 

may have batteries in the 3.7 to 4.8 volt range, while larger tools such as drills have batteries 

clustered around 7.2, 12, and 14.4 volts. Based on limited information, DOE estimates that 

battery energy for DIY tool batteries fewer than 12 volts is typically less than 15 watt hours.o 

DIY tools between 12 and 18 volts tend to have battery ratings around between 14 and 55 watt 

hours.p Most professional power tools use 18 volt batteries. DOE’s research found median 

battery energy among professional tools to be 54 watt hours.q 

3.2.1.9 Transport 

The transport category includes an assortment of applications powered by BCs, including 

toy ride-on vehicles, golf cars, mobility scooters, and others. While many electric vehicles are 

included in this category, automobiles, as defined by the U.S. Department of Transportation, are 

not. See chapter 2 for further explanation. 

Transport 

Electric Vehicles 

Electric Scooters 

Motorized Bicycles 

Golf Carts 

Toy Ride-On Vehicles 

Mobility Devices 

Wheelchairs 

Mobility Scooters 

Large Battery 

Chargers 

Marine/Automotive/RV 

Chargers 

DOE estimates that 8.6 million BCs for transport applications are shipped annually. Of 

these, 7.1 million are for toy ride-on vehicles.35 While DOE assumes lifetimes for toy ride-on 

o Based on a sample of five DIY tools. 

p Based on a sample of five DIY tools. q Based on a sample of 13 professional tools. 

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vehicles to be about 4 years, other transport applications have lifetimes of approximately 10 

years. (PG&E et al., No. 20 at p. 11) While 6-, 12-, and 24-volt batteries are common among 

these applications, battery energy varies dramatically from 27 to over 9,000 watt-hours. The 

output powers of the BCs and EPSs that power these batteries also vary considerably. 

Electric Vehicles 

The electric vehicles subcategory includes BCs for golf cars, chargers for marine and 

recreational vehicle (RV) batteries, toy ride-on vehicles, motorized bicycles, and electric 

scooters. 

The golf car market includes a wide range of vehicle types, from standard golf carts to 

heavy duty ―utility vehicles‖, which are designed to carry loads over difficult terrain. The 

research firm International Market Solutions (IMS) calls this broad category of products, ―small 

task-oriented vehicles‖ and each vehicle type may be purchased by consumers. These vehicles 

are steadily moving towards battery power. IMS estimates that the market share of electric small 

task-oriented vehicles has increased from 56 percent in 2000 to 64 percent in 2006 and they 

estimate the electric share will increase to 70 percent by 2012.36 The same golf car models are 

often sold to both the golf course fleet market and to private consumers. Furthermore, many fleet 

golf cars are later sold in the consumer market as used vehicles. IMS estimates that over 210,000 

electric small task-oriented vehicles were shipped in 2008. Shipments are expected to grow at a 

CAGR of 4.2 percent from 2006 to 2012. As mentioned above, DOE excludes golf cars 

manufactured for on-road use. These vehicles are automobiles and fall outside DOE’s scope. 

Based on DOE’s analysis of currently available products, most golf cars employ several 6 or 12 

volt batteries and energy greater than 3,000 watt hours. Common golf car BCs have output 

voltages of 36 or 48 volts. 

DOE is also considering large universal battery chargers in its scope, such as those used 

to charge batteries for marine trolling motors. DOE has found that these battery chargers are 

functionally equivalent to those used to charge batteries for recreational vehicle (RV) 

accessories, automotive and motorcycle starter batteries, and other applications. Marine and RV 

applications use one or more 12 volt deep cycle batteries, depending on the requirements of the 

accessories being operated. PG&E estimates 2009 shipments of large universal BCs to be 

500,000 units and have lifetimes of ten years. (PG&E et al., No. 20 at p. 10) Large universal BCs 

typically have output powers of 12 volts, although 24-volt universal BCs are not uncommon. 

These BCs are used when more than one battery is being charged, as may be the case in some 

marine and RV applications. Deep cycle marine batteries store approximately 830 watt hours of 

energy. r 

Toy ride-on vehicles make up the great majority of shipments battery charged transport 

shipments. Toy Industry Association, Incorporated reported that 2008 retail sales in the U.S. 

were $1.9 billion.37 Based on an estimated average retail price of $210, DOE estimated 

shipments to be just over nine million units per year.s 

r Based on test unit.
 s DOE examined the retail prices of best-selling toy ride-on vehicles available from Wal-Mart, Toys R Us, and
 

Amazon.com. Web sites examined September 2009.
 

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These vehicles have BCs with output voltages of 6, 12 and 24 volts and energy between 

27 and 144 watt hours. Based on the recommended age levels for these products, DOE estimates 

toy ride-on vehicles to have a service life of four years.t Since the market for these applications is 

mature, and because the population of children age one to six is projected to grow at a compound 

annual growth rate of only 0.65 percent during the analysis period, DOE does not expect 

significant growth in this market.38 

Electric scooters and motorized bicycles are the remaining applications DOE analyzed. 

Based on recalls of toy scooters, DOE estimates that annual sales of electric scooters are at least 

250,000 units per year.u DOE estimates annual shipments of electric bicycles to be 150,000 units 

in 2008.39 The scooters and motorized bicycles DOE analyzed used batteries ranging from 24 to 

48 volts. Batteries had rated energy between 108 and 456 watt hours. The Segway brand scooter 

is unique in that it uses two 73.6 volt batteries (each at 427 watt hours of energy). DOE found 

little information wall adapters for these applications. 

Mobility Devices 

Battery-powered wheelchairs and mobility scooters are common BC applications used by 

individuals with mobility-limiting disabilities, obesity, arthritis and other medical conditions. In 

early 2008, the market research firm Marketstrat, Inc. forecasted that 166,000 powered 

wheelchairs and 192,000 mobility scooters shipped in 2008.40 

Powered wheelchairs and mobility scooters use similar batteries and chargers. All of the 

mobility devices examined by DOE were powered by two 12 volt batteries wired in series for a 

total output of 24 volts. Battery energy for a single battery ranged from 144 to 900 watt hours 

and with common devices employing pairs of either 144 watt hour batteries or batteries in the 

range around 400 watt hours. 

The market research firm Global Industry Analysts anticipates shipments of mobility 

devices to grow by 10 percent CAGR between 2011 and 2015, primarily driven by an aging 

population.41 Over the analysis period, the population aged 65 and older is expected to grow at 

2.8 percent CAGRv

, compared to 0.56 percent CAGR for the population under age 65.38 

3.2.2 Shipments, Lifetimes, and Energy Performance 

Awareness of annual product shipment trends and lifetimes is an important aspect of the 

market assessment and the development of the standards rulemaking. For this rulemaking, DOE 

relied on data from public sources, interested parties, industry reports, and its own estimates. 

t According to surveys of retailer websites, typical age categories are one to two years of age for low-powered 

vehicles and two to six years of age for more powerful vehicles. 

u Based on recall data from the Consumer Product Safety Commission. Data show that recalls of individual models 

account for significant shipments. For example see: U.S. Consumer Product Safety Commission. ―CPSC, Razor 

USA Announce Recall of Electric Scooters.‖ June 14, 2005. (Last accessed September 13, 2010.) 

<http://www.cpsc.gov/CPSCPUB/PREREL/prhtml05/05193.html> The September 13, 2010 material from this 

website is available in Docket # EERE-2008-BT-STD-0005. For more information, contact Ms. Brenda Edwards at 

(202) 586-2945.
 v The annual growth rate of the over-65 population is estimated to be 3.36 percent in 2013. It will decline slightly
 

during the analysis period and is forecast to be 1.42 percent by 2032.
 

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DOE used these data for three main purposes. First, DOE used the shipments data to select the 

representative product classes and representative units for the engineering analysis. Generally, 

DOE selected product classes and units to reflect the most common BC and EPS types used in 

the United States today (see section 3.3 and chapter 5 of the preliminary analysis). Second, DOE 

used the lifetime data in its lifecycle cost analysis (chapter 8) and to develop its inventory model 

for the national impact analysis (see chapter 10 of the preliminary TSD).Third, the shipment data 

and market trend information contributed to the shipments forecast used in the national impact 

analysis (see chapter 9 of the preliminary analysis). 

3.2.2.1 External Power Supply Shipments, Lifetimes and Energy Performance 

DOE estimates that a total of 301 million EPSs shipped in 2008. Of these, 288.6 million 

were Class A EPSs and 12.4 million were non-Class A EPSs. In 2005, an estimated 296 million 

EPSs were shipped, which represents a compound annual growth rate of 0.6 percent. To estimate 

shipments of EPSs for consumer products in 2005, DOE reanalyzed data from its Draft 

Technical Report on BCs and EPSs.42 Table 3.3 shows the average lifetime and an estimate of 

the number of units shipped in 2008 for each of four segments of product class A1, the three 

other Class A EPS product classes, and the 11 non-Class A EPS product classes. No products 

were identified in four of the non-Class A EPS product classes. 

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EERE-2008-BT-STD-0005 COMMENT 31
 

Table 3.3 External Power Supply Lifetimes and Shipments by Product Class 

Output Class ID Average 

Lifetime 

Shipments 

in 2008 (estimated) 

Class A 

AC-DC Basic 

Voltage 

Low Voltage 

A1 (0-10.25 W) 

A1 (10.26-39 W) 

A1 (40-90 W) 

A1 (91-250 W) 

4.6 76,227,000 

4.4 66,721,000 

4.0 52,994,000 

3.3 10,235,000 

A2 4.1 72,195,000 

AC-AC Basic 

Voltage 

Low Voltage 

A3 

A4 

7.3 7,994,000 

4.9 2,250,000 

Non-Class A 

Multiple-Voltage 100 W 

≥100 W 

X1 

X2 

5.0 3,782,000 

5.0 4,901,000 

High Power >250 W H1 4.4 3,000 

For Medical 

Devices 

ACDC 

Basic 

Voltage 

Low Voltage 

M1 

M2 

7.9 1,534,000 

12.0 25,000 

ACAC 

Basic 

Voltage 

Low Voltage 

M3 

M4 

- 0 

- 0 

For MotorOperated BC 

Applications 

and Detachable 

Batteries 

ACDC 

Basic 

Voltage 

Low Voltage 

B1 

B2 

4.7 1,884,000 

4.4 275,000 

ACAC 

Basic 

Voltage 

Low Voltage 

B3 

B4 

- 0 

- 0 

The following 18 tables show EPS shipment estimates and lifetimes for the top 

applications in each product class. Product class A1 is subdivided into four segments by 

nameplate output power. 

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Table 3.4 EPS Product Class A1a: Top Applications, Shipments, and Lifetimes 

Top Applications by Shipments 

2008 EPS Shipments 

(Units) 

Average Lifetime 

(Years) 

1. Answering Machines 20,175,000 5 

2. Cordless Phones 19,151,000 5.3 

3. Mobile Phones 13,140,000 4 

4. Portable Video Game Systems 10,884,000 3 

5. In-Vehicle GPS 7,660,000 5 

Other 5,217,000 -

Total 76,227,000 4.6 

―Other‖ includes baby monitors, breast pumps, caller ID devices, clock radios, consumer two way radios, electronic 

pest repellents, guitar effects pedals, keyboards, pre-amps, personal digital assistants, and wireless headphones. 

Includes EPSs between 0 and 10.25 watts nameplate output power. 

Table 3.5 EPS Product Class A1b: Top Applications, Shipments, and Lifetimes 

Top Applications by Shipments 

2008 EPS Shipments 

(Units) 

Average Lifetime 

(Years) 

1. LAN Equipment 27,581,000 4 

2. VoIP Adapters 8,845,000 5 

3. Digital Picture Frames 7,472,000 5 

4. Portable DVD Players 7,140,000 4 

5. MP3 Speaker Docks 7,012,000 4 

Other 8,671,000 -

Total 66,721,000 4.4 

―Other‖ includes camcorders, clock radios, computer speakers, external hard drives, image scanners, hedge 

trimmers, portable printers, weed trimmers, and wireless speakers. Total may not match individual unit count due to 

rounding. Includes EPSs between 10.25 and 39 watts nameplate output power. 

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Table 3.6 EPS Product Class A1c: Top Applications, Shipments, and Lifetimes 

Top Applications by Shipments 

2008 EPS Shipments 

(Units) 

Average Lifetime 

(Years) 

1. Notebook Computers 30,225,000 3.3 

2. Video Game Consoles 13,512,000 5 

3. Ink Jet Imaging Equipment 5,557,000 5 

4. Netbook Computers 3,700,000 3.5 

Total 52,994,000 4 

Includes EPSs between 39 and 90 watts nameplate output power. 

Table 3.7 EPS Product Class A1d: Top Applications, Shipments, and Lifetimes 

Top Applications by Shipments 

2008 EPS Shipments 

(Units) 

Average Lifetime 

(Years) 

1. Notebook Computers 10,075,000 3.3 

2. LED Monitors 160,000 4 

Total 10,235,000 3.3 

Includes EPSs between 90 and 250 watts nameplate output power. 

Table 3.8 EPS Product Class A2: Top Applications, Shipments, and Lifetimes 

Top Applications by Shipments 

2008 EPS Shipments 

(Units) 

Average Lifetime 

(Years) 

1. Mobile Phones 52,560,000 4 

2. In-Vehicle GPS 7,660,000 5 

3. MP3 Players 4,373,000 4 

4. Portable Video Game Systems 2,893,000 3 

5. Personal Digital Assistants (PDA) 1,582,000 4 

Other 3,127,000 -

Total 72,195,000 4.1 

―Other‖ includes Bluetooth headsets, digital cameras, consumer two way radios, e-book readers, electronic pest 

repellents, handheld GPS units, handheld image scanners, rechargeable toothbrushes, and rechargeable water jets. 

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Table 3.9 EPS Product Class A3: Top Applications, Shipments, and Lifetimes 

Top Applications by Shipments 

2008 EPS Shipments 

(Units) 

Average Lifetime 

(Years) 

1. Home Security Systems 4,219,000 7.3 

2. Aquarium Accessories 1,750,000 5 

3. Water Softeners and Purifiers 1,150,000 11 

4. Indoor Fountains 500,000 4.7 

5. Irrigation Timers 375,000 10 

Total 7,994,000 7.3 

Table 3.10 EPS Product Class A4: Top Applications, Shipments, and Lifetimes 

Top Applications by Shipments 

2008 EPS Shipments 

(Units) 

Average Lifetime 

(Years) 

1. Aquarium Accessories 1,750,000 5 

2. Indoor Fountains 500,000 4.7 

Total 2,225,000 4.9 

Table 3.11 EPS Product Class X1: Top Applications, Shipments, and Lifetimes 

Top Applications by Shipments 

2008 EPS Shipments 

(Units) 

Average Lifetime 

(Years) 

1. Ink Jet Imaging Equipment 3,782,000 5 

Total 3,782,000 5 

Table 3.12 EPS Product Class X2: Top Applications, Shipments, and Lifetimes 

Top Applications by Shipments 

2008 EPS Shipments 

(Units) 

Average Lifetime 

(Years) 

1. Video Game Consoles 4,901,000 5 

Total 4,901,000 5 

Table 3.13 EPS Product Class H1: Top Applications, Shipments, and Lifetimes 

Top Applications by Shipments 

2008 EPS Shipments 

(Units) 

Average Lifetime 

(Years) 

1. Amateur Radios 3,000 10 

Total 3,000 10 

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Table 3.14 EPS Product Class M1: Top Applications, Shipments, and Lifetimes 

Top Applications by Shipments 2008 EPS Shipments 

(Units) 

Average Lifetime 

(Years) 

1. Sleep Apnea Machines 1,000,000 8 

2. Medical Nebulizers 450,000 7 

3. Portable Oxygen Concentrators with 

lower output EPS (<100 watts 50,000 11 

4. Blood Pressure Monitors 25,000 12 

5. Portable Oxygen Concentrators with 

higher output EPS (>100 watts) 9,000 11 

Total 1,534,000 7.9 

Table 3.15 EPS Product Class M2: Top Applications, Shipments, and Lifetimes 

Top Applications by Shipments 

2008 EPS Shipments 

(Units) 

Average Lifetime 

(Years) 

1. Blood Pressure Monitors 25,000 12 

Total 25,000 12 

Table 3.16 EPS Product Class M3: Top Applications, Shipments, and Lifetimes 

Top Applications by Shipments 

2008 EPS Shipments 

(Units) 

Average Lifetime 

(Years) 

1. No Known Applications - -

Total 0 -

Table 3.17 EPS Product Class M4: Top Applications, Shipments, and Lifetimes 

Top Applications by Shipments 

2008 EPS Shipments 

(Units) 

Average Lifetime 

(Years) 

1. No Known Applications - -

Total 0 -

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Table 3.18 EPS Product Class B1: Top Applications, Shipments, and Lifetimes 

Top Applications by Shipments 

2008 EPS Shipments 

(Units) 

Average Lifetime 

(Years) 

1. Toy Ride-On Vehicles 355,000 4 

2. RC Toys 350,000 2 

3. DIY Power Tools (External Battery) 281,000 5.9 

4. DIY Power Tools (Integral Battery) 234,000 5.9 

5. Handheld Vacuums 209,000 6 

Other 457,000 -

Total 1,884,000 4.7 

―Other‖ includes air mattress pumps, blenders, electric scooters, flashlights and lanterns, hair clippers, mixers, 

motorized bicycles, robotic vacuums, shavers, stick vacuums, and universal battery chargers. Total does not match 

individual unit count due to rounding. 

Table 3.19 EPS Product Class B2: Top Applications, Shipments, and Lifetimes 

Top Applications by Shipments 

2008 EPS Shipments 

(Units) 

Average Lifetime 

(Years) 

1. Shavers 164,000 4.1 

2. Beard and Moustache Trimmers 59,000 4.5 

3. Hair Clippers 38,000 5 

4. Can Openers 14,000 5 

Total 275,000 4.4 

Table 3.20 EPS Product Class B3: Top Applications, Shipments, and Lifetimes 

Top Applications by Shipments 

2008 EPS Shipments 

(Units) 

Average Lifetime 

(Years) 

1. No Known Applications - -

Total 0 

Table 3.21 EPS Product Class B4: Top Applications, Shipments, and Lifetimes 

Top Applications by Shipments 

2008 EPS Shipments 

(Units) 

Average Lifetime 

(Years) 

1. No Known Applications - -

Total 0 -

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Table 3.22 shows the distribution of EPS shipments by efficiency level in 2009. DOE 

weighted tested units by their application shipments to derive efficiency distributions for product 

class A1. The distributions for product classes A2, A3, and A4 are assumed to be equivalent to 

those for product class A1. Although product classes M1, M2, B1, and B2 have EPSs of similar 

construction to Class A EPSs, they are not subject to EISA standards. (DOE found no products in 

M3, M4, B3, or B4.) DOE assumed that 10 percent of the market had efficiencies that fell below 

EISA, while the remaining products had a similar distribution to Class A EPSs. The distributions 

for product classes X1, X2, and H1 were taken from the determination analysis of non-Class A 

EPSs. These distributions underlie the base case efficiency forecasts presented in chapter 9. 

Table 3.22 Energy Performance of New External Power Supplies in 2009 

Output Class 

ID 

Percent of Market at Each CSL 

CSL 0 CSL 1 CSL 2 CSL 3 CSL 4 CSL 5 

Class A 

AC-DC 

Basic 

Voltage 

Low 

Voltage 

A1 

A2 

68 17 12 3 0 -

68 17 12 3 0 -

AC-AC 

Basic 

Voltage 

Low 

Voltage 

A3 

A4 

68 17 12 3 0 -

68 17 12 3 0 -

Non-Class A 

Multiple-Voltage <100 W X1 100 0 0 0 - -

≥100 W X2 5 95 0 0 - -

High Power >250 W H1 60 40 0 0 - -

For Medical 

Devices 

ACDC 

Basic 

Voltage 

Low 

Voltage 

M1 

M2 

10 58 17 12 3 0 

10 58 17 12 3 0 

For MotorOperated BC 

Applications 

and 

Detachable 

Batteries 

ACDC 

Basic 

Voltage 

Low 

Voltage 

B1 

B2 

10 58 17 12 3 0 

10 58 17 12 3 0 

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DOE’s Draft Technical Report contained estimates of EPS efficiency before federal 

standards for Class A EPSs took effect in 2008. Table 3.23 shows the efficiency of units on the 

market in 2007 from least efficient (Baseline Line Frequency EPS) to most efficient (Federal 

Standard). 

Table 3.23 Energy Performance of External Power Supplies in 2007 

Efficiency Level 

EPS Output Power 

0 to < 4 W 

(percent) 

≥ 4 to ≤ 60 W 

(percent) 

> 60 W 

(percent) 

Baseline Line Frequency EPS 35 16 0 

Baseline Switch Mode EPS 25 44 60 

Federal Standard 

(effective July 1, 2008 40 40 40 

3.2.2.2 Battery Charger Shipments, Lifetimes and Energy Performance 

DOE estimates that nearly 402 million BCs shipped in 2008. In 2005, 250 million BCs 

were shipped, which represents a compound annual growth rate of 17 percent. To estimate 

shipments of BCs for consumer products in 2005, DOE reanalyzed data from its Draft Technical 

Report on BCs and EPSs.42 

Table 3.24 shows, for each of the ten BC product classes DOE defined, the average lifetime and 

an estimate of the number of units shipped in 2008. 

Table 3.24 Battery Charger Lifetimes and Shipments by Product Class 

Battery 

Energy 

Battery 

Voltage 

Class 

ID 

Average 

Lifetime 

Shipments in 

2008 

(estimated) 

ACDC 

<100 Wh 

Inductive 

Connection 1 5.0 5,354,000 

<4 V 2 3.2 206,221,000 

4<10 V 3 4.9 23,116,000 

≥10 V 4 4.6 69,758,000 

100– 

3000 Wh 

<20 V 5 5.5 2,333,000 

≥20 V 6 8.5 940,000 

>3000 

Wh 7 9.7 214,000 

DC-DC <9 V Input 8 3.3 71,825,000 

≥9 V Input 9 5.1 15,519,000 

AC-AC 

AC Output 

from 

Battery 

10 6.0 6,900,000 

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The following ten tables show BC shipment estimates and lifetimes for the top 

applications in each product class. 

Table 3.25 BC Product Class 1: Top Applications, Shipments, and Lifetimes 

Top Applications by BC Shipments 

2008 BC Shipments 

(Units) 

Average Lifetime 

(Years) 

1. Rechargeable Toothbrushes 4,868,000 5 

2. Rechargeable Water Jets 487,000 5 

Total 5,354,000 5 

Total does not match individual unit count due to rounding. 

Table 3.26 BC Product Class 2: Top Applications, Shipments, and Lifetimes 

Top Applications by Shipments 

2008 BC Shipments 

(Units) 

Average Lifetime 

(Years) 

1. Mobile Phones 105,120,000 2 

2. Answering Machines 20,175,000 5 

3. Cordless Phones 19,151,000 5.3 

4. Portable Video Game Systems 13,777,000 3 

5. Digital Cameras 10,879,000 6 

Other 37,119,000 -

Total 206,221,000 3.4 

―Other‖ includes baby monitors, Bluetooth headsets, beard and moustache trimmers, can openers, e-book readers, 

hair clippers, handheld GPS units, home security system components, MP3 players, MP3 speaker docks, PDAs, and 

shavers. 

Table 3.27 BC Product Class 3: Top Applications, Shipments, and Lifetimes 

Top Applications by Shipments 2008 BC Shipments 

(Units) 

Average Lifetime 

(Years) 

1. Portable DVD Players 7,140,000 4 

2. Camcorders 4,206,000 4.9 

3. Toy Ride-On Vehicles 3,548,000 4 

4. RC Toys 2,100,000 2 

5. DIY Power Tools with external battery 1,753,000 5.9 

Other 4,369,000 -

Total 23,116,000 4.5 

―Other‖ includes air mattress pumps, blenders, DIY power tools with integral battery, handheld vacuums, hobby 

grade RC cars, mixers, stick vacuums, universal battery chargers, and wireless speakers. 

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Table 3.28 BC Product Class 4: Top Applications, Shipments, and Lifetimes 

Top Applications by Shipments 

2008 BC Shipments 

(Units) 

Average Lifetime 

(Years) 

1. Notebook Computers 40,300,000 3.3 

2. Professional Power Tools 11,688,000 5.4 

3. DIY Power Tools with external battery 5,259,000 5.9 

4. Netbook Computers 3,700,000 3.5 

5. Handheld Vacuums 2,797,000 6 

Other 6,014,000 -

Total 69,758,000 4.2 

―Other‖ includes flashlights and lanterns, medical nebulizers, portable printers, robotic vacuums, sleep apnea 

machines, stick vacuums, toy ride-on vehicles, universal battery chargers, and weed and hedge trimmers. 

Table 3.29 BC Product Class 5: Top Applications, Shipments, and Lifetimes 

Top Applications by Shipments 2008 BC Shipments 

(Units) 

Average Lifetime 

(Years) 

1. Toy Ride-On Vehicles 1,774,000 4 

2. Auto/Marine/RV Chargers 500,000 10 

3. Portable Oxygen Concentrators 59,000 11 

Total 2,333,000 5.5 

Table 3.30 BC Product Class 6: Top Applications, Shipments, and Lifetimes 

Top Applications by Shipments 2008 BC Shipments 

(Units) 

Average Lifetime 

(Years) 

1. Electric Scooters 250,000 10 

2. Mobility Scooters 192,000 10 

3. Lawn Mowers 182,000 6 

4. Powered Wheelchairs 166,000 9.7 

5. Motorized Bicycles 150,000 7 

Total 940,000 8.7 

Table 3.31 BC Product Class 7: Top Applications, Shipments, and Lifetimes 

Top Applications by Shipments 2008 BC Shipments 

(Units) 

Average Lifetime 

(Years) 

1. Small Task Oriented Vehicles (Golf 

Cars) 214,000 6.4 

Total 214,000 6.4 

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Table 3.32 BC Product Class 8: Top Applications, Shipments, and Lifetimes 

Top Applications by Shipments 2008 BC Shipments 

(Units) 

Average Lifetime 

(Years) 

1. MP3 Players 39,358,000 4 

2. Mobile Phones 26,280,000 2 

3. Digital Cameras 2,720,000 6 

4. Personal Digital Assistants (PDA) 1,779,000 4 

5. Camcorders 1,402,000 4.9 

Other 286,000 -

Total 71,825,000 3.4 

―Other‖ includes Bluetooth headsets, e-book readers, and handheld GPS units. Total may not match individual unit 

count due to rounding. 

Table 3.33 BC Product Class 9: Top Applications, Shipments, and Lifetimes 

Top Applications by Shipments 2008 BC Shipments 

(Units) 

Average Lifetime 

(Years) 

1. In Vehicle GPS 15,320,000 5 

2. Medical Nebulizers 90,000 7 

3. Portable Oxygen Concentrators 59,000 11 

4. Flashlights and Lanterns 50,000 10 

Total 15,519,000 5.1 

Table 3.34 BC Product Class 10: Top Applications, Shipments, and Lifetimes 

Top Applications by Shipments 2008 BC Shipments 

(Units) 

Average Lifetime 

(Years) 

1. Uninterruptible Power Supplies 6,900,000 6 

Total 6,900,000 6 

Table 3.35 shows the distribution of BC shipments by efficiency. DOE derived efficiency 

distributions for product classes 1, 2, 4, 5, and 10 from an examination of the efficiency of tested 

units. The efficiency distribution for product class 7 is based on manufacturer interviews 

(discussed in chapter 5), while the distributions for product classes 3, 6, 8, and 9 are scaled from 

those for the other product classes. These distributions underlie the base case efficiency forecasts 

presented in chapter 9. DOE lacks historical data on BC efficiency. 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

Table 3.35 Energy Performance of New Battery Chargers in 2009 

Battery 

Energy 

Battery 

Voltage 

Class 

ID 

Percent of Market at Each CSL 

CSL 0 CSL 1 CSL 2 CSL 3 

AC ­

DC 

<100 

Wh 

Inductive 

Connection 1 75 12.5 12.5 0 

<4 V 2 39.2 58 2.8 0 

4<10 V 3 34 54 12 0 

≥10 V 4 18.7 43 38.3 0 

100– 

3000 

Wh 

<20 V 5 43.4 16.3 40.3 0 

≥20 V 6 50 20 30 0 

>3000 Wh 7 50 20 30 0 

DC-DC <9 V Input 8 39.2 58 2.8 0 

≥9 V Input 9 39.2 58 2.8 0 

AC-AC 

AC Output 

from 

Battery 

10 88.9 11.1 0 0 

3.2.3 Other Energy Efficiency Programs 

There are many domestic and foreign energy efficiency programs designed to improve 

the energy performance of BCs and EPSs. Those programs that might affect the United States 

market are discussed below, first EPS and then BC programs. Information about these programs 

informed DOE’s base case efficiency forecasts, which it developed as part of the shipments 

analysis (see chapter 9). 

The first mandatory energy efficiency standards for EPSs were introduced in California 

and Oregon in 2007. On December 19, 2007, the President signed into law the Energy 

Independence and Security Act of 2007 (EISA 2007) (P.L. 110-140), which set a Federal 

standard for Class A EPSs that took effect on July 1, 2008. Because the EPS market is global, 

this standard led to improvements in the efficiency of EPSs sold worldwide. Furthermore, the 

standard, while intended to regulate only Class A EPSs, is likely having a spillover effect on the 

efficiency of BCs and non-Class A EPSs. The standard for Class A EPSs has increased the 

demand for, and lowered the cost of, some of the more efficient components and has stimulated 

the adoption of improved designs. Because some of the same techniques and components are 

used to manufacture both Class A EPSs and other EPSs and BCs, DOE assumes that some of 

these components and designs are being carried over into the design and manufacture of BCs and 

non-Class A EPSs. 

In the United States, manufacturers can use the ENERGY STAR label to differentiate 

more-efficient EPSs from less efficient ones. Version 2.0 of the ENERGY STAR criteria for 

EPSs took effect on November 1, 2008. As of September 15, 2009, there were already over 

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3,000 qualified models.43 EPA estimated that 47 percent of EPSs sold in the United States in 

2008 met ENERGY STAR specifications.44 

In April 2010 an EPS standard that is equivalent to the current Federal standard for Class 

A EPSs took effect in the European Union. In 2011 a more stringent standard, equivalent to 

version 2.0 of the ENERGY STAR criteria, will take effect. The Darnell Group estimates that the 

E.U. will receive 33 percent of all EPS shipments in 2011, which is nearly equivalent to the 

North American share of shipments. Given the size of the E.U. market, EPS standards there will 

likely cause spillover effects, increasing the efficiency of EPSs sold in the United States. 

A recent industry agreement for mobile phones known as the ―GSMA Universal 

Charging Solution‖ could drive down the energy consumption of EPSs used with these products. 

The agreement incorporates a no-load (―standby‖) power consumption requirement that is 

stricter than both the current Federal standard and ENERGY STAR criteria. 

ENERGY STAR is currently the only efficiency program for BCs in the United States. 

Because the criteria, which took effect on January 1, 2006, do not cover active mode, they cannot 

be directly compared to the CSLs in DOE’s analysis. EPA estimates that 16 percent of BCs sold 

in the United States met the ENERGY STAR criteria in 2008.44 

In fact, there are no standards for BCs in effect anywhere that include requirements for 

active mode, although many governing bodies have indicated their intent to harmonize around a 

DOE BC standard (if the Department sets an energy conservation standard). Although not a 

current regulation, the Pacific Gas and Electric Company developed a standard for BCs that 

includes active mode, which it proposed to the California Energy Commission (CEC) for 

adoption. Should California adopt this standard, it may impact the efficiency of BCs on the 

market nationwide. Comparisons between the proposed PG&E BC standard and DOE’s CSLs 

are difficult to make because the PG&E standard is specified as a continuous function whereas 

DOE defined separate CSLs for each product class. However, DOE found that in some product 

classes, products at the best-in-market CSL would meet the PG&E standard and that in all 

product classes, products at the max-tech CSL would meet the PG&E standard. When possible, 

DOE intends to analyze BC units at an ―improved‖ level above the best-in-market CSL. 

DOE encourages interested parties to inform DOE of other upcoming or updated 

programs that may impact the energy efficiency of BCs and EPSs sold in the United States. 

Table 3.36 summarizes a number of voluntary and mandatory energy efficiency programs for 

BCs and EPSs. For detailed information on these programs, please refer to appendix 3B. 

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Table 3.36 BC and EPS Efficiency Programs Worldwide 

Country / 

State 

Program Name Effective Date Compliance Coverage 

US EISA 2007 2008 Mandatory EPS 

ENERGY STAR 2006 (BC) 

2008 (EPS) 

Voluntary BC, EPS 

California Tier II Standard for ―State 

Regulated‖ EPSs 

2008 Mandatory EPS 

Battery Charger Standard Under 

Consideration 

Mandatory BC 

Australia/ 

New Zealand 

Minimum Energy 

Performance Standards 

2008 (AU) 

2009 (NZ) 

Mandatory 

(Mark III) 

Voluntary 

(Mark IV, V) 

EPS 

Canada Canadian Standards 

Association 

2010 

(projected) 

Mandatory EPS 

China China National Institute of 

Standardization (CNIS) 

~2010 Mandatory EPS 

China Standard 

Certification Center (CSC) 

2005 Voluntary EPS 

European 

Union 

Energy using Products 

(EuP) 

2010 version 1 

2011 version 2 

Mandatory EPS 

EU Code of Conduct 2009 Voluntary EPS 

Group for Energy Efficient 

Appliances 

2007 Voluntary BC, EPS 

Manufacturers’ 

Agreement 

GSMA Universal 

Charging Solution (mobile 

phones) 

2012 Voluntary EPS 

Israel SI 4665.2 2007 Voluntary EPS 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

Country / 

State 

Program Name Effective Date Compliance Coverage 

Korea Minimum Energy 

Performance Standards 

2009 Mandatory EPS 

e-Standby 2007 Voluntary BC, EPS 

3.2.4 Production and Distribution 

DOE’s BC and EPS distribution models were created based on information gathered 

through market research, conversations with industry experts, and stakeholder feedback. The 

Association of Home Appliance Manufacturers and others commented that, despite several ways 

to market, most BCs and EPSs follow a similar distribution path. The most common path to 

market, as identified by DOE, is depicted by the gray arrows in Figure 3.4, while alternative 

paths are depicted by the white arrows. The distribution channels DOE identified are discussed 

below. 

BC and EPS distribution begins with component manufacturers, who produce the 

circuitry, circuitry components, wiring, housing, and other materials needed to manufacture BCs 

and EPSs. DOE learned that demand for specific components can drive their prices down. This is 

sometimes the case for components used to make a BC or EPS more efficient. Given greater 

demand for efficient components, due to an efficiency standard, for example, component 

manufacturers increase production and the increased scale causes prices to fall. 

Components are often sold directly to BC/EPS manufacturers, who produce a finished 

BC or EPS, often for a specific end-use product manufacturer. Although less common, some 

BCs or EPSs may be manufactured directly by the end-use product manufacturer (OEM). DOE 

does not have data on the total size of the BC industry, but the Darnell Group estimated the size 

of the EPS industry. It estimated that in 2005, over 300 manufacturers worldwide made EPSs. 

Most of these manufacturers are located abroad. In the aggregate, their revenues totaled 

45,12 $5 billion in 2005 and $6.7 billion in 2008. It should be noted that many of these 

manufacturers also produce other products, including BCs and internal power supplies, so it is 

difficult to get an exact value of EPS market size. 

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Component Manufacturer 

BC/EPS Manufacturer 

BC/EPS Distributor 

Consumer Product Retailer/Distributor 

End-Use Product Manufacturer (OEM) 

Taxes 

Consumer 

*Note that widths of arrows are not drawn to scale and are not meant to be an exact indication of a distribution 

path’s relative prominence. 

Figure 3.4 Paths of Distribution for Battery Chargers and External Power Supplies 

BCs and EPSs are then typically purchased by an end-use product manufacturer, 

henceforth known as the original equipment manufacturer, or OEM, as an input to an end-use 

consumer product. The BC and/or EPS is typically packaged with a consumer product, or 

especially in the case of some BCs, integrated into the consumer product. 

Retailers typically purchase BCs and EPSs from OEMs and sell the products to 

consumers, though DOE has identified a number of instances where the manufacturing and retail 

operations for a product are owned and managed by one company. An example is Apple, which 

manufactures its own consumer electronics for sale in its own Apple-branded retail stores. 

In addition to the standard distribution chain described above, market research and stakeholder 

comment revealed additional BC and EPS distribution channels. These are discussed below. 

DOE found that many OEMs with low production volumes opt to purchase BCs or EPSs from 

distributors because they provide easy access to a wide array of components. Because sourcing 

BCs and EPSs through a distributor may be more costly, most OEMs with larger production 

volumes eliminate this step by working directly with component and BC/EPS manufacturers. 

DOE also notes that while most consumer products are manufactured in an OEM-owned factory, 

there is a trend towards the use of electronics manufacturing services (EMSs). OEMs can take 

advantage of greater economies of scale in source materials and components by contracting out 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

the manufacture of specific consumer applications to an EMS. EMSs achieve these economies of 

scale by producing similar products for several OEMs. 

3.2.5 Small Businesses 

During this rulemaking process, DOE is considering the possible impacts to small 

businesses that may be imposed by increased energy conservation standards for battery chargers 

and external power supplies. The Small Business Administration (SBA) determines appropriate 

guidance as to what is considered a small business for all industries described under the North 

American Industry Classification System (NAICS)w. BC and EPS manufacturers fall under 

NAICS code 335999 (All Other Miscellaneous Electrical Equipment and Component 

Manufacturing). Based on this code, SBA defines a BC or an EPS manufacturer to be a small 

business if it employs no more than 500 employees. Throughout its analysis of the BC/EPS 

market space, DOE will attempt to gauge the prevalence of small businesses within these 

industries. 

3.2.6 Manufacturers and Market Shares 

The Darnell Group estimated revenues of the top EPS manufacturers in their 2005 report 

on the EPS market. They noted that the great majority of EPS manufacturing takes place in 

China and Taiwan. Furthermore, many of the largest manufacturers are also based in Asia. 

Figure 3.5 shows the top EPS manufacturers worldwide in 2005.45 Because of the global reach of 

the industry and the reliance of major manufacturers on producing for high volume applications, 

Darnell notes that there are very few differences in regional market shares. In 2005, there were 

over 300 manufacturers producing EPSs. DOE learned that the industry has seen consolidation, 

but it found that the manufacturers shown in Figure 3.5 remain independent of one another. None 

of the top manufacturers listed in Figure 3.5 are headquartered in the United States. DOE 

identified SL Power Electronics, a subsidiary of SL Industries, Inc., as an EPS manufacturer 

based in the United States. SL Power develops, manufactures, and markets products under the 

brand names CONDORTM and AULT®. DOE also recognizes that some EPSs for niche 

applications may be manufactured in the United States. 

w For a more detailed description of SBA’s small business definitions, see 

http://www.sba.gov/idc/groups/public/documents/sba_homepage/sba_010224.pdf 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

Percent of 2005 Revenue 

Delta Electronics 9.4% 

Lite-on Technology 7.2% 

Astec 5.8% 

FRIWO Group 5.1% 

Phihong 5.0% 

Salcomp 3.6% 

Leader Electronics 2.8% 

AcBel Polytech 2.1% 

FSP Group 1.9% 

Dee Van Enterprises 1.8% 

Others 55.3% 

$5 

Billion 

Figure 3.5 Top EPS Manufacturers in 2005 

Battery charger manufacturing is split between companies that produce BCs for OEMs 

and OEMs that produce BCs ―in house.‖ DOE currently lacks market share information for BC 

manufacturers but it gathered some data from its manufacturing interviews (discussed in chapter 

5). DOE learned that in most cases low-energy BCs are not produced by the OEM of the end-use 

product; rather, they are purchased from an original device manufacturer (ODM), supplier, or 

vendor typically based in Asia. Conversely, medium and high energy products’ BCs, such as 

those for wheelchairs and golf cars, are typically manufactured in the U.S. For example, Lester 

Electrical manufactures BCs for both wheelchairs and golf cars and has U.S.-based 

manufacturing. Xantrax Technology Inc. is based in Canada, but has facilities in the U.S. They 

produce BCs for marine applications. Many power tool OEMs also have some U.S.-based 

manufacturing. Companies include Black & Decker, TTI (maker of Milwaukee, Ryobi, and 

Hoover brand products), and the Robert Bosch Tool Corporation (Bosch, Skil). 

3.2.7 Trade Associations and Other Interested Parties 

DOE has identified a number of organizations that may have an interest in this 

rulemaking. Energy efficiency advocacy organizations with a demonstrated interest in DOE’s 

rulemakings on battery chargers and external power supplies include 

Appliance Standards Awareness Project, 

American Council for an Energy-Efficiency Economy, 

Earthjustice, 

Natural Resources Defense Council, 

Pacific Gas and Electric Company, and 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

Southern California Edison. 

There are a substantial number of trade associations with member companies that 

manufacture or sell BCs, EPSs, or the consumer products they power. DOE has identified 39 

such trade associations, listed in Table 3.37 along with the products that DOE believes each 

association has an interest in. 

Table 3.37 Trade Associations 

Association Name Products and Applications 

Alarm Industry Communications Committee Home Security Systems 

Amateur Radio Relay League (ARRL) Amateur Radios 

American Association of Cleaning Equipment 

Manufacturers 

Floor Care Appliances 

Association of Home Appliance Manufacturers 

(AHAM) 

Home Appliances 

Battery Council International Batteries 

Cellular Telecommunications Industry Association 

(CTIA) 

Cell Phones 

Computer and Communications Industry Association Computers and Peripherals 

Consumer Electronics Association (CEA) Consumer Electronics 

Craft and Hobby Association RC Cars (Hobby Grade) 

Electric Drive Transportation Association Electric Vehicles 

Electronic Components Association Battery Chargers, External Power 

Supplies 

Hobby Manufacturers Association RC Cars (Hobby Grade) 

Information Technology Industry Council (ITIC) Computers and Peripherals 

International Disk Drive Equipment and Materials 

Association 

External Media Drives, External Hard 

Drives 

International Housewares Association Kitchen Appliances, Floor Care, 

Personal Care 

International Music Products Association Keyboards, Guitar Effects Pedals, 

Electric Music Instruments 

International Recording Media Association International Recording Media 

Association 

Irrigation Association Irrigation Timers 

Juvenile Products Manufacturers Association prenatal to preschool electronics 

Motorcycle Industry Council Electric Scooters 

Multifunction Products Association Multifunction Devices (MVD's) 

National Association of Manufacturers (NAM) All 

National Bicycle Dealers Association Electric Bicycles 

National Burglar & Fire Alarm Association Home Security Systems 

National Electrical Manufacturers Association 

(NEMA) 

All 

National Gardening Association Outdoor Appliances 

National Marine Manufacturers Association Marine Electronics 

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Association Name Products and Applications 

National Pest Management Association Electronic Pest Repellents 

National Retail Federation All 

Photo marketing Association Photo marketing Association 

Portable Computer and Communications Association Notebooks, Netbooks, Handheld 

Computers, Mobile Phones, Bluetooth 

Portable Rechargeable Battery Association (PRBA) Batteries 

Power Sources Manufacturers Association (PSMA) Batteries, Power Supplies 

Power Tool Institute (PTI) DIY Power Tools, Professional Power 

Tools 

Security Industry Association Home Security Systems 

TechAmerica ALL 

Telecommunications Industry Association Telephony 

The National Mobility Equipment Dealers Association Electric Wheelchairs 

Toy Industry Association RC Toys, Toy Ride-On Vehicles 

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3.3 PRODUCT CLASSES 

When necessary, DOE divides covered products into classes by the type of energy used, 

the capacity of the product, and any other performance-related feature that justifies different 

standard levels, such as features affecting consumer utility. (42 U.S.C. 6295(q)) DOE then 

conducts its analysis and considers establishing or amending standards to provide separate 

standard levels for each product class. This section is a continuation of the discussion in chapter 

2 where DOE summarized comments submitted by interested parties relating to product classes. 

3.3.1 EPS Product Classes 

The following sections summarize all of the factors that DOE considered as potential 

determinants for EPS product classes. When discussing EPS efficiency DOE refers to efficiency 

as the matched pairing of active mode average efficiency and no-load mode power consumption. 

3.3.1.1 Nameplate Output Power 

Nameplate output power is a measure of the maximum power that an EPS can deliver, 

which directly impacts capacity and efficiency. EPSs with greater nameplate output power offer 

the consumer greater capacity and tend to have higher active mode average efficiency. EPSs with 

lower nameplate output power tend to have lower no-load power consumption. 

EPS active mode average efficiency reflects the power consumption (loss) within an EPS, 

which comes from two sources: conversion losses and overhead losses. Conversion losses are 

proportional to the power that the EPS outputs whereas overhead losses are essentially fixed 

losses that do not increase significantly once output power is greater than 50 watts. Therefore, 

EPSs with higher output powers have proportionally lower overhead losses and are more 

efficient, when compared to EPSs with lower output power. In contrast to average efficiency, 

EPS no-load power consumption improves (is less) for EPSs with nameplate output power less 

than 50 watts because those EPSs have lower overhead requirements and can therefore shut 

down more fully when not providing output power. Because of these factors, both the EISA 

standard and Energy Star 2.0 specification determine a minimum efficiency level as a continuous 

function of nameplate output power, as shown by the average efficiency levels in Figure 3.6 and 

the no-load power levels in Figure 3.7. DOE acknowledges that nameplate output power 

significantly affects utility and efficiency and therefore different nameplate output powers may 

warrant unique product classes. However, rather than create distinct product classes by 

nameplate output power, DOE proposes to follow the precedent set by EISA and Energy Star 2.0 

such that DOE intends to set an efficiency standard level as a continuous function of nameplate 

output power. 

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0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 50 Minimum AVerage EFficiency in ACtive Mode [%]

Nameplate Output Power [watts]

EISA

Energy Star 2.0 Regular Voltage

Energy Star 2.0 Low Voltage

Figure 3.6 The EISA Standard and Energy Star 2.0 Specification for Average Efficiencyx 

0

0.1

0.2

0.3

0.4

0.5

0.6

0 50 Maximum Power Consumption in No-Load Mode [watts]

Nameplate Output Power [watts]

EISA

Energy Star 2.0 AC/DC

Energy Star 2.0 AC/AC

Figure 3.7 The EISA Standard and Energy Star 2.0 Specification for No-Load
 

Power Consumption
 

x Energy Star 2.0 describes the two specification levels as ―standard‖ and ―low voltage.‖ Because DOE uses 

―standard‖ as a term of art, the Energy Star 2.0 ―standard‖ level is referred to as the Energy Star 2.0 ―regular‖ level 

throughout this document. 

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3.3.1.2 Nameplate Output Voltage 

Nameplate output voltage affects utility because the main function of an EPS is to 

provide an application with power at a certain voltage rather than 115 volts provided by mains. 

The specific nameplate output voltage is determined by the characteristics of the application. For 

instance, certain applications such as modems and computer monitors use have digital circuitry 

that requires specific power at a specific voltage, such as 12V. For these applications the EPS 

provides power at the necessary voltage. Therefore, output voltage offers consumers a distinct 

utility that affects efficiency, which is one of the factors highlighted for special consideration 

under 42 U.S.C. 6295(q)(1). 

EPSs with higher output voltage will tend to be more efficient. This arises because of the 

relationship between power, voltage, and current: power (P) = current (I) × voltage (V). For an 

EPS with a given output power, the voltage decreases as current increases. This is important 

because many of the losses in a BC or an EPS are functions of current. For instance, the resistive 

loss through a wire is I2 × R and the power consumption of a diode is I × Vdiode. Table 3.38 

illustrates this phenomenon: EPS A’s output voltage is half that of EPS B, but EPS A’s I

2 × R 

losses four times as high. Although the example is for a 20-watt EPS, it is applicable to all EPSs 

because they all have I2 × R losses. 

Table 3.38 Comparison of I2 × R Losses for Two 20-watt EPSs 

Nameplate Output Voltage 

[volts] 

Nameplate Output Current 

[amps] 

I

2 × R Losses 

[watts] 

EPS A 10 2 4 × R 

EPS B 20 1 1 × R 

Energy Star 2.0 acknowledged the relationship between voltage and efficiency by setting less 

stringent active mode average efficiency criteria for EPSs with low voltage and high current 

output (Figure 3.6). Energy Star 2.0 defined ―low voltage‖ models as EPSs with nameplate 

output voltage less than six volts and nameplate output current greater than or equal to 550 

milliamps. Figure 3-8 shows the distribution of EPSs qualifying for Energy Star 2.0 as of 2009; 

many low-voltage EPSs would not have qualified at the regular level. DOE proposes to have 

different product classes for EPSs with regular voltage output and low voltage output. DOE 

proposes to use the Energy Star criteria to define low voltage EPSs because the criteria 

adequately capture many low voltage EPSs in the market and to follow precedent. 

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40%

50%

60%

70%

80%

90%

100%

0 2 0 4 0 6 0 8 0 100

Efficiency [%]

Power Out [Watts]

EnergyStar- Most Efficient AC-DC EPSs - Sept 2009

Standard EPSs

Low Voltage EPSs

EnergyStar 2.0 

Standard

EnergyStar 2.0 LowVoltage

EISA Level

Figure 3-8 EPSs Qualifying for Energy Star 2.0 as of September 2009. 

3.3.1.3 Type of Power Conversion (AC/AC versus AC/DC) 

All EPSs receive input power from mains in the form of alternating current (AC) and provide 

output power in the form of either AC power or direct current (DC) power. This is another key 

functionality of an EPS, along with providing power at a specific voltage. Again, the type of 

power conversion the EPS provides is governed by its application. Applications such as mobile 

phones and laptops require DC power to match the type of power provided by the battery. 

Applications that tend to use EPSs that provide AC power, such as cordless phones, often have 

conversion circuitry within the application for AC-DC conversion. 

The type of power conversion is indicative of an EPS’s internal circuitry, hence its capability to 

conserve energy. EPSs that provide AC output power typically consist of just a transformer. The 

no-load power losses of those EPSs are dominated by transformer core losses. Alternatively, 

EPSs that provide DC power output typically contain a transformer as well as overhead circuitry 

that control the flow of power through the EPS . Overhead circuitry provides EPSs with DCoutput power the ability to reduce power consumption in no-load mode whereas EPSs with ACoutput power do not typically contain overhead circuitry. Energy Star 2.0 acknowledges this 

relationship by setting a less stringent no-load mode power consumption criterion for EPSs with 

AC output power (Figure 3.7). DOE proposes to have different product classes for EPSs with AC 

output power and DC output power. 

3.3.1.4 Use with Medical Equipment 

Another condition by which EPCA defines a Class A EPS is that it does not include any device 

that ―requires Federal Food and Drug Administration listing and approval as a medical device in 

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accordance with section 513 of the Federal Food, Drug, and Cosmetic Act (21 U.S.C. 360c).‖ 

(42 U.S.C. 6291(36)(C)(ii)(I)) Thus, all EPSs used with medical devices must meet the special 

requirements of UL 60601 (Underwriters Laboratories standard for power supplies for medical 

devices) such that they are approved by the Federal Food and Drug Administration (FDA). Use 

with medical devices is a utility that is unique to medical EPSs. Medical EPSs are exempted 

from EISA 2007 efficiency standards; therefore DOE expects that there may be medical EPSs in 

the market with efficiencies lower than required by EISA 2007 for Class A EPSs. 

3.3.1.5 Use with Battery Chargers of Motorized Applications and Detachable Batteries 

A further condition by which EPCA defines a Class A EPS is that it does not ―power the charger 

of a detachable battery pack or charges the battery of a product that is fully or primarily motor 

operated.‖ (42 U.S.C. 6291(36)(C)(ii)(II)) Thus, per EPCA, DOE considers EPSs for battery 

chargers of motorized applications and detachable batteries" (MADB EPSs) to have a unique 

utility from Class A EPSs. Products that are fully or primarily motor operated include portable 

rechargeable household appliances such as handheld vacuums, personal care products such as 

shavers, and power tools. MADB EPSs are exempted from EISA 2007 efficiency standards; 

therefore DOE expects that there may be MADB EPSs in the market with efficiencies lower than 

required by EISA 2007 for Class A EPSs. 

3.3.1.6 EPS Product Classes Under Consideration 

For all the reasons discussed above, DOE is considering the EPS product classes listed in Table 

3.39, Table 3.40, Table 3.41, Table 3.42, and Table 3.43. Under these product classes, an EPS’s 

product class is determined by the type of power conversion it provides as well as its type of 

output voltage. DOE proposes using the same criteria as Energy Star 2.0 to distinguish low 

voltage EPSs from regular voltage EPSs, as discussed in section 3.3.1.2. Within each product 

class, the standard level will vary with nameplate output power and output cord length. Chapter 5 

of this preliminary TSD provides detail on the selection of candidate standard levels. 

Table 3.39 Proposed Class A EPS Product Classes. 

Regular Voltage Output Low Voltage Output * 

AC-DC Conversion 

AC-AC Conversion 

A1 

A3 

A2 

A4 

* Low voltage output EPSs have nameplate output voltage less than six volts and nameplate output current greater 

than or equal to 550 milliamps. All other EPSs are regular voltage output. 

Table 3.40 Proposed Multiple Voltage EPS Product Classes. 

# 

Nameplate Output Power < 100 watts 

Nameplate Output Power ≥ 100 watts 

X1 

X2 

Table 3.41 Proposed High Power EPS Product Classes. 

# 

Nameplate Output Power > 250 watts H1 

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Table 3.42 Proposed Medical EPS Product Classes. 

Basic Voltage Output Low Voltage Output * 

AC-DC Conversion 

AC-AC Conversion 

M1 

M3 

M2 

M4 

* Low voltage output EPSs have nameplate output voltage less than six volts and nameplate output current greater 

than or equal to 550 milliamps. All other EPSs are basic voltage output. 

Table 3.43 Proposed MADB EPS Product Classes. 

Basic Voltage Output Low Voltage Output * 

AC-DC Conversion 

AC-AC Conversion 

B1 

B3 

B2 

B4 

* Low voltage output EPSs have nameplate output voltage less than six volts and nameplate output current greater 

than or equal to 550 milliamps. All other EPSs are basic voltage output. 

3.3.2 BC Product Classes 

In this section, DOE will present the BC characteristics it considered for use in setting 

BC product classes, the impacts of power converter topology on BC design, and finally, the 

resultant product classes DOE used in the preliminary analysis. 

3.3.2.1 BC Product Class Criteria Considered for the Preliminary Analysis 

In chapter 2, DOE summarized the comments it received from interested parties 

regarding product classes. DOE then evaluated the criteria for setting product classes suggested 

in the comments against the requirements of 42 U.S.C. 6295(q), resulting in the following BC 

characteristics for further evaluation as criteria for setting product classes: 

output power; 

battery voltage; 

battery capacity; 

battery energy; and 

inductive charging. 

The above factors were combined with these additional factors that DOE took into account based 

on its review of BCs in the market: 

input voltage type (line AC or low-voltage DC); and 

AC output. 

Output power, battery voltage, battery capacity, and battery energy apply to all BCs, and
 

are related through the following equations, which were presented previously in chapter 2.
 

P_max >~ E_batt ∙ r, 

E_batt = C_batt ∙ V_batt
 

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Where: 

P_max is the maximum output power, in watts 

E_batt is battery energy, in watt-hours 

r is the charge rate, in units of C or 1/hour 

C_batt is the battery capacity, in ampere-hours 

V_batt is the battery voltage, in volts 

As can be seen in the above equations, the four BC characteristics are related. BC output 

power is primarily affected by the charge rate and the battery energy, which in turn, is the 

product of battery capacity and voltage. 

Of these BC characteristics, DOE is using battery voltage and battery energy as a primary 

means of dividing product classes for the preliminary analysis. In addition, DOE is also using 

input and output characteristics, such as inductive charging, input voltage type (line AC or lowvoltage DC), and AC output to divide BCs into further product classes. 

As mentioned earlier in chapter 2, battery voltage greatly affects consumer utility, 

because the electronics of a portable consumer product are designed to require a particular 

battery voltage. Whereas change in battery capacity would impact the runtime of a batteryoperated product, a change in battery voltage may stop it from running altogether. Furthermore, 

BCs charging lower-voltage batteries tend to be less efficient, and could be disproportionately 

affected by an equally stringent standard level across all voltages. Therefore, DOE is using 

battery voltage and not battery capacity as a characteristic for setting product classes in the 

preliminary analysis. 

Whereas battery voltage specifies which consumer product applications can be used with 

a particular battery (and its corresponding BC), battery energy describes the total amount of 

work that the battery can perform, regardless of the application. Battery energy is therefore also a 

measure of utility. Furthermore, because a BC must provide enough output power to replenish 

the energy discharged during use, the capacity and physical size of the BC depend on the battery 

energy.y By using battery energy as a proxy for output power, DOE is using one criterion for 

classifying BCs instead of two, simplifying the potential BC energy conservation standards while 

sufficiently accounting for any differences in BC capacity or utility in the standards analysis. 

Finally, DOE is also using the presence of inductive charging, DC input voltage, and AC 

output from the battery as additional characteristics for setting product classes. Since only a 

small subset of BC products have inductive charging, DC input voltage, or AC output from the 

battery, product classes based on these criteria typically fall within one of the larger classes 

based on battery voltage and energy mentioned above. 

y The minimum output power is a product of battery energy and charge rate. However, while charge rates rarely fall 

outside the range of 1 C to 10 C, the battery energy of consumer BCs can span over 5 orders of magnitude from 

1 watt-hour to over 10,000 watt hours. Therefore, the output power is more dependent on battery energy. 

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Inductive charging was described previously in chapter 2 as a utility-related characteristic 

designed to promote cleanliness and guarantee uninterrupted operation of the BC in a wet 

environment. 

Input voltage type was not identified by interested parties as a potential characteristic for 

setting product classes. Nonetheless, while conducting an analysis of the market for BCs, DOE 

identified numerous BCs that do not include a wall adapter, connecting instead to a personal 

computer’s USB port or a car’s cigarette lighter receptacle. Because input voltage can have a 

differential impact on BC efficiency and, furthermore, because input voltage determines where 

the BC can be used, impacting utility, DOE is using this characteristic as a criterion for 

developing further product classes beyond the ones specified above. BCs differentiated on the 

basis of the above criteria have been further divided based on input voltage in the preliminary 

analysis to account for the efficiency losses associated with the AC-DC conversion process. 

3.3.2.2 Impacts of Topology on Product Class Selection 

As explained in the above discussion, battery voltage, battery energy, and the presence of 

certain input or output characteristics (e.g., inductive charging) may impact the efficiency of 

battery chargers. However, since they also affect the capacity and utility of a charger, DOE must 

specify a separate standard level that takes into account any differences in energy consumption 

due to differences in these characteristics. Whereas this is straightforward in the case of 

inductive charging—i.e., there can be separate product classes with separate standards, 

depending on whether a BC uses inductive charging—matters are more complicated in the case 

of battery voltage and battery energy. 

Battery voltage depends on the number and chemistry of electrochemical cells in the 

battery; while battery energy further depends on the amount of active material in the battery (i.e., 

its capacity). Because the size of the battery is infinitely variable, and the battery can contain 

between one and 24 or even more cells, it is possible to establish an arbitrary number of product 

classes based on these criteria. While too many product classes would unnecessarily complicate 

the analysis and any resultant energy conservation standards, too few product classes may lead to 

product classes so large that the BCs that fall inside them have few characteristics in common. 

Because DOE conducts its standards analysis by estimating the cost impacts of increasing the 

efficiency of a representative unit, it is important that the product classes be delineated such that 

the products within the class are similar to the representative unit. 

To resolve the question of product class size, DOE examined the topology, or underlying 

design, of the power converters that transform input voltage to DC voltage suitable for charging 

a battery. The power converter topology determines which technology options can be practically 

used to improve the efficiency of a BC. Even though converters of a given topology can vary 

depending on capacity and other requirements, many of the technology options will remain 

applicable. Basing its product classes on the underlying BC topology therefore allows DOE to 

focus its BC standards analysis on a representative unit within each product class and extrapolate 

the results for that unit to all products of a similar topology within the class. 

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3.3.2.3 Resultant BC Product Classes 

DOE first divided BCs into three groups by type of input and output: those with AC input 

and DC output, those with DC input and DC output, and those with AC input and AC output. 

While many factors influence the choice of topology—including experience of the 

designer, capabilities of the production facility, time to market, and cost of materials, among 

others—output power also has a significant effect. Since output power is correlated to battery 

energy, DOE researched power converter design guides and manufacturer literature and 

evaluated BCs for various applications, in an attempt to generalize the division of topologies by 

battery energy. Based on this initial review of topologies, DOE has divided BCs into three 

battery energy product classes: 

(I)	 Battery energy less than 100 watt-hours. Most BCs for consumer products charge 

batteries smaller than 100 watt-hours and typically rely on line-frequency and flyback 

designs. Batteries tend to have lithium-ion or nickel chemistries. 

(II) Battery energy greater than or equal to 100 watt-hours and less than 3,000 watthours. BCs that charge batteries in this range tend to use forward and half-bridge 

power converter designs. They are used with wheelchair, marine, and lawn mower 

applications that rely on sealed lead-acid batteries. 

(III)	 Battery energy greater than or equal to 3,000 watt-hours. BCs that charge 

batteries larger than 3,000 watt-hours tend to use ferro-resonant or full-bridge 

designs. Their only consumer application is mobility—i.e., golf cars and utility 

vehicles, which use flooded lead-acid batteries. 

However, battery energy (and therefore topology) is not the only factor that determines 

the practicality of technology options that can be used to increase the efficiency of a given BC. 

Battery voltage not only constrains which end-use consumer product a given BC can service, as 

mentioned above, it also impacts the design of the charger itself. In particular, while certain 

technology options may be practical at one voltage, the same may not be true at another voltage, 

even within the same topology. 

Therefore, for the preliminary analysis, DOE further divided the above battery-energy 

based product classes by voltage, dividing the low-energy product class (number I, above) into 

low-, medium-, and high-voltage product classes. Similarly, DOE divided the medium-energy 

product class (number II, above) into low- and high-voltage product classes. These product 

classes along with the others used for the BC preliminary analysis are shown in Table 3.44. 

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Table 3.44 BC Product Classes Used in the Preliminary Analysis. 

Prod. 

Class # Example Applications 

AC In, 

DC Out 

< 100 

Wh 

Inductive 

Connection 1 Toothbrushes 

0-4 V 2 Telephones 

4–10 V 3 Cameras and Small Tools 

10–48 V 4 Laptops and Large Tools 

100– 

3,000 

Wh 

0–24 V 5 Marine Chargers, Wheelchairs 

24–48 V 6 Electric Bikes, Lawnmowers 

> 3000 Wh 7 Golf Cars 

DC In, 

DC Out 

5 V Input 8 USB Chargers 

12 V Input 9 Car Chargers 

AC In, 

AC Out 

AC Output 

from Battery 10 Uninterruptible Power Supplies 

3.4 TECHNOLOGY ASSESSMENT 

3.4.1 Introduction 

This technology assessment examines BC and EPS technology, with a focus on the 

factors affecting their efficiency. It begins by explaining the purpose of EPSs and BCs and their 

modes of operation (sections 3.4.2 and 3.4.7). Next, the technology assessment reviews 

efficiency metrics and the test procedures established for assessing the performance of EPSs and 

BCs in the major energy-consuming modes (sections 3.4.2.1 and 3.4.8). Finally, the assessment 

discusses the designs necessary for BCs and EPSs to perform their required function 

(sections 3.4.5 and 3.4.9), and the technology options to improve the performance of those 

designs against the energy efficiency metrics (sections 3.4.6 and 3.4.10). DOE reviewed these 

technology options in the screening analysis and considered them in the engineering analysis to 

establish the relationship between cost and efficiency. 

3.4.2 EPS Modes of Operation 

3.4.2.1 EPS Active Mode 

In active mode, the external power supply takes power from mains and converts it to a 

form usable by the consumer product or load. For the determination analysis, DOE used the 

definition of active mode codified in 10 CFR part 430 subpart B appendix Z: ―Active mode is the 

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0%

20%

40%

60%

80%

100%

0% 25% 50% 75% 100%

Output current, Iout, as percent of maximum load current, Imax [%] Efficiency [%]

mode of operation when the external power supply is connected to the main electricity supply 

and the output is connected to a load.‖ 

In this mode, EPS efficiency is the conversion efficiency when the load draws some or all 

of the maximum rated output power of the EPS. To provide that output power, the EPS also 

consumes power due to internal losses as well as overhead circuitry. The amount of power the 

EPS consumes varies with the power demands of the load; together, those two parameters define 

the EPS’s efficiency at a particular loading point: 

out EPS consumption

out

In

out

EPS P P

P

P

P

_

Eq. 3.1 

EPS efficiency varies with the amount of output power. Typically, EPS efficiency is 

lower between 0 and 20 percent of maximum rated output power and higher between 20 and 100 

percent of maximum rated output power, where EPSs tend to operate. The lower efficiency at 

lower output current is due to the proportionally larger power consumption of internal EPS 

components, relative to output power. At higher power, EPS overhead losses increase slightly, 

but have less of an effect on EPS efficiency than losses associated with power conversion. The 

EPS test procedure evaluates active mode conversion efficiency at four loading points: 25 

percent, 50 percent, 75 percent, and 100 percent of maximum rated output power, which captures 

a general picture of EPS efficiency. Figure 3.9 shows an example of a typical efficiency curve 

for an EPS in active mode. 

Figure 3.9 Example of an Efficiency Curve of an EPS in Active Mode 

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3.4.2.2 EPS No-Load Mode 

For the determination analysis, DOE used the definition of no-load mode codified in 10 

CFR part 430 subpart B appendix Z: ―No load mode means the mode of operation when the 

external power supply is connected to the main electricity supply and the output is not connected 

to a load.‖ 

EPS efficiency in no-load mode is characterized by EPS power consumption, rather than 

conversion efficiency, because the EPS does not deliver power to the load in this mode. 

However, the EPS might provide functionality. For example, certain consumer products may 

require the EPS to deliver output power within moments of being connected. Thus, the EPS may 

consume power to provide the useful function of reduced start-up time. Nonetheless, EPS power 

consumption can be low (less than 0.5 watts) in no-load mode. 

3.4.3 EPS Efficiency Metrics 

An evaluation of the technology options for efficiency improvement and the tradeoffs 

between them depends on the metrics used. DOE has previously adopted test procedures for 

measuring the energy consumption of both BCs and EPSs.z This section presents a brief 

overview of the test procedures for EPSs, and any issues related to the test procedures that may 

affect the energy conservation standards rulemaking. See section 3.4.8 for a similar discussion of 

BCs. 

3.4.4 Energy Efficiency Metrics for External Power Supplies 

On December 8, 2006, DOE codified a test procedure final rule for EPSs in Appendix Z 

to Subpart B of 10 CFR Part 430 (―Uniform Test Method for Measuring the Energy 

Consumption of External Power Supplies.‖) DOE’s test procedure, based on the California 

Energy Commission (CEC) EPS test procedure, measures active-mode efficiency and no-loadmode (standby-mode) power consumption. 

Active mode conversion efficiency is the ratio of output power to input power. DOE 

averages the efficiency at four loading conditions—25, 50, 75, and 100 percent of maximum 

rated output current—to assess the performance of an EPS when powering diverse loads. DOE 

also measures the power consumption of the EPS when disconnected from the consumer product, 

which is termed no-load power consumption. DOE combines both of the above metrics into 

―matched pairs‖ that describe the candidate standard levels considered in setting potential energy 

conservation standards. This ―matched pairs‖ combination affected the analysis and is discussed 

further in Chapter 5, Engineering Analysis. 

3.4.5 EPS Designs 

EPS’s must meet several specifications in order to power a consumer product; EPSs are 

generally designed to provide power at a fixed output voltage with variable current to a 

consumer product. The consumer product is what determines the EPS design criteria, including 

output power, output voltage and the tolerance of the output voltage. EPSs designed for 

consumer products that require precise voltages (e.g., computers) will also incorporate output 

z 10 CFR Part 430 Subpart B Appendix Y and Appendix Z 

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voltage regulation to minimize voltage fluctuations caused by load or power source variations. 

Other applications that can tolerate voltage fluctuation may use simpler EPSs that do not regulate 

the output voltage as tightly. 

Together, output power and output voltage determine the current, which has the greatest 

impact on conduction losses and associated power dissipation in the EPS. 

Unregulated and two-stage regulated EPSs are called line-frequency EPSs because the 

frequency of the current passing through their transformers is the same as that of the AC mains 

current (nominally 60 Hz in the United States). Switched-mode power supplies (SMPS) convert 

power differently than line-frequency EPSs. SMPSs first rectify the AC mains voltage to DC, 

converting it back to AC by switching the current on and off at high frequency. The highfrequency AC current then passes through the primary winding of a transformer while the output 

from the secondary winding of the transformer is rectified, resulting in a low-voltage DC output. 

Because of the high frequency of the AC current passing through the transformer, the 

transformer can be made smaller, resulting in lower weight, material costs, and losses in the 

transformer. 

3.4.5.1 AC/AC External Power Supplies 

An AC/AC external power supply is the simplest type of EPS, typically consisting only 

of a transformer. A transformer contains two wires wrapped around a metal core; as current 

passes through the primary wire, power is transferred to the secondary wire (usually at a lower 

voltage) through magnetic induction in the core. The induced voltage depends on the relative 

number of turns between the primary and the secondary wires. The windings of the transformer 

are wound so that the voltage generated in the secondary wire is at the design voltage for the 

consumer product when mains voltage is applied to the primary wire. Because the primary and 

secondary windings are two separate wires, the transformer also provides a safety function, 

electrically isolating the consumer product from mains. The key factors that determine 

transformer losses are core size, core material, number of windings, and wire gauge. 

+

VOut

-

Transformer +

VMains -

Primary Secondary

Figure 3.10 Circuit Diagram for an AC/AC External Power Supply 

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3.4.5.2 Unregulated Line-Frequency AC/DC External Power Supplies 

In unregulated line-frequency EPSs, the two main sources of loss are the transformer and 

the rectifying diodes. After passing through the transformer, current passes through rectifier 

diodes, which have voltage drops that also dissipate power. Typically, diodes have a drop of 0.6 

volts, which constitutes a proportionally larger share of the losses at lower output voltages. For 

AC-DC EPS that have a low output voltage, below approximately 12 V the power consumed by 

the diodes also becomes significant. A line-frequency raw supply has three distinct stages 

(Figure 3.11): a transformer to isolate and step down mains voltage, a rectifier to convert AC 

voltage to DC voltage, and a filter capacitor to smooth the output voltage. 

Transformer Rectifier Filter +

VMains -

Primary Secondary +

VOut

-

Figure 3.11 Circuit Diagram of a Line-Frequency Raw Supply 

The raw supply, consisting of a transformer, rectifier, and filter capacitor, is directly 

responsive to the load. A change in mains power or the resistance of the load directly affects the 

output voltage of the raw supply. If required, a regulator circuit follows the raw supply circuit, 

housed either in the EPS or in the end-use product before the load. 

3.4.5.3 Linear-Regulated Line-Frequency AC/DC External Power Supplies 

To achieve voltage regulation, manufacturers can add a second stage, such as a linear 

regulator, to the line-frequency power conversion stage described above, or redesign the power 

conversion stage entirely using a switched-mode topology. Of the two regulator technologies, 

linear regulators are simpler, bulkier, cheaper, and generally less efficient at higher power levels 

than switching regulators. Switching regulators, although more complicated and costly, provide a 

good alternative when portability or over-heating is a concern, such as when an EPS is used with 

a mobile phone charger or a high-power flat-panel television. 

The AC-DC conversion stage of a regulated line-frequency EPS is essentially the same as 

that of an unregulated EPS, with the same sources of power consumption. The linear voltage 

regulation stage adds to these losses by passing power from the AC-DC converter to the 

consumer product through a power-dissipating element. This regulation stage senses the output 

voltage and adjusts the voltage across it to keep the output voltage proportional to a fixed 

reference voltage. Loss in a regulated line-frequency EPS is caused by the conversion stage 

delivering current at a higher voltage than needed by the consumer product, and dropping the 

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excess voltage across the regulator to achieve the lower regulated output voltage. Dissipated as 

heat, the power lost in the regulator is the product of the voltage drop and the load current. 

Linear regulators have two key elements: a sensor and a pass device, which work 

together to produce a fixed output voltage (Figure 3.12). To determine those adjustments, the 

sensor element continuously compares the output voltage to a reference voltage. Whenever there 

is a difference between the two voltages, the sensor directs the pass device to adjust the output in 

order to reduce that difference. This continuous adjustment allows the regulator to yield a 

constant output voltage as the load resistance or mains voltage varies. The output voltage of the 

linear regulator circuit is what the user sees as the output voltage of the EPS. 

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Raw Supply Stage Mains Power Pass Device

Sensor

Linear Regulator Stage VOut

Figure 3.12 Block Diagram of a Linear Regulator 

Figure 3.13 shows a circuit diagram of a ―low-dropout‖ linear regulator, one of the more 

common types of linear regulators. To determine that voltage drop, an operational amplifier 

(commonly referred to as an ―op-amp‖) acts as a sensor that compares the output voltage against 

a reference voltage. Based on those two signals, the op-amp controls a transistor, which is the 

pass device. The voltage drop across the transistor determines the output voltage but also 

dissipates energy. The energy dissipated by the pass device is the main source of energy 

consumption in the linear regulator, and hence the main source of inefficiency and heat 

generation. Together, the sensor and the pass device adjust the output of the regulator to produce 

a relatively stable output voltage, which is what the load receives as the output voltage of the 

EPS. 

+

VRawSupply_out - VReference +VOut

-

Pass Device

-

+ Op

Amp Sensor

Heat Dissipated

Figure 3.13 Simplified Circuit Diagram of a Linear Regulator 

The efficiency of the linear regulator, ηLinReg, is: 

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LinReg out LinReg in I I_ _

 

 

Lin_ EPS RawSupp

*

LinReg

 

LinReg in LinReg in

LinReg out LinReg out

LinReg in

LinReg out

LinReg V I

V I

P

P

_ _

_ _

_

_

Eq. 3.2 

where PLinReg_out is the power out of the linear regulator, 

PLinReg_in is the power into the linear regulator, 

VLinReg_out is the voltage out of the linear regulator, 

VLinReg_in is the voltage into the linear regulator, 

ILinReg_out is the current out of the linear regulator, and 

ILinReg_in is the current into the linear regulator. 

Because the linear regulator connects to the raw supply, VLinReg_in is equal to VRawSupp_out, 

the output voltage of the raw supply. Furthermore, because the input current flows directly to the 

output through the pass device, with other currents being negligible, . 

Therefore, the efficiency of the linear regulator alone is approximately: 

LinReg in

LinReg out

LinReg V

V

_

_

Eq. 3.3 

The total efficiency of an EPS with a linear regulator depends on the efficiency of both 

the linear regulator stage and the raw supply stage. Depending on the load conditions, ηLinReg 

generally ranges from 0.6 to 0.8, meaning the linear regulator is about 60 to 80 percent efficient. 

The efficiency of the raw supply, ηRawSup, also varies with the load, but is generally from 0.7 to 

0.9. The raw supply and linear regulator each are most efficient at different load conditions. 

Multiplied, ηLinReg and ηRawSupp yield the total efficiency of an EPS with a linear regulator, 

ηLin_EPS, which is generally about 50 percent, but is lower for EPSs with output power below 

10 W: 

Eq. 3.4 

For an EPS consisting of a raw supply and a linear regulator, mains voltage at line 

frequency (60 Hz) is directly applied to the transformer. If the power applied to the transformer 

had similar voltage and current characteristics but a higher frequency, the transformer could be 

smaller and lighter. Those benefits are part of the motivation for choosing switching regulators, 

which, unlike their linear counterparts, have transformers that operate at high frequency (greater 

than 20 kHz). 

3.4.5.4 Switching-Regulated Line-Frequency AC/DC External Power Supplies 

A switching regulator can also follow the line-frequency AC-DC power-conversion stage 

in place of the linear regulator described above, which is different from the switched-mode EPS 

discussed below. These tend to be much more efficient than linear regulators because they do not 

dissipate excess power through a linear control element. Rather, they switch the current at high 

frequency, adjusting the proportion of on time during each switching cycle (i.e., the duty ratio) to 

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maintain the regulated output voltage proportional to a fixed reference. Due to their higher costs, 

these switching regulators tend not to be as common as linear regulators. 

Raw Supply 

Stage 

Mains 

Power Chopper 

Control 

Switching Regulator Stage 

Energy 

Transfer 

Feedback 

Isolation 

VOut 

Figure 3.14 Block Diagram of a Switching-Regulated Line-Frequency AC/DC EPS 

3.4.5.5 Switched-Mode AC/DC External Power Supplies 

The most common method for regulating power to a consumer product is a switchedmode EPS. The critical elements in a switched-mode EPS are the transistor, output rectifier, bulk 

capacitor, transformer, and controller. A transistor acts as a switch that constrains the flow of 

power rectified from mains into the transformer (or choke), through the output rectifier, and, 

ultimately, to the consumer product. A controller, typically an integrated circuit, switches the 

transistor on and off based on the output voltage. By adjusting the duty ratio, the IC controls the 

rectified mains current into the primary winding of the transformer and thereby the output 

voltage of the EPS. The IC can also limit power dissipation in active mode by switching at low 

current or low voltage. Further, the IC can greatly increase efficiency by reducing power 

consumption in no-load mode, the condition when the EPS has been disconnected from the load, 

resulting in zero output current. After passing through the transformer, the current is rectified and 

filtered before reaching the consumer product. Principal sources of loss in a switched-mode EPS 

are the transistor switching transients, magnetization and resistive losses as a result of 

transformer current, controller IC power consumption, and rectifier losses. Although there are 

more sources of loss for switched-mode EPSs than line-frequency EPSs, in total, losses in 

switched-mode EPSs tend to be lower. 

The switching regulator consists of five stages: an AC-DC conversion stage, a chopper 

stage, an energy transfer stage, a control stage, and a feedback isolation stage (Figure 3.15). 

First, the current is rectified and passed to the chopper, which converts the DC voltage back to 

AC, but at high frequency. The energy transfer stage then takes energy from the chopper, briefly 

stores it, and then passes it to the rectifier to be output to the consumer product. The energy 

transfer stage also serves to isolate the user from the mains. The level of the output voltage is fed 

back through an isolation stage to the controller, which tracks the output voltage and adjusts the 

chopper to make the desired voltage. 

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AC/DC Conversion Mains Chopper

Control VOut Feedback Isolation

Energy Transfer Switched-mode Power Supply

Figure 3.15 Block Diagram of a Switched-Mode Power Supply 

The switching regulator usually consists of an integrated circuit controller and discrete 

components. The circuit diagram in Figure 3.16 depicts a ―flyback‖ switching regulator, one of 

the more common types; however, many other switching regulator designs also exist. The 

AC/DC conversion stage consists of a diode bridge and filter capacitor, similar to a raw supply. 

In this case, current flows directly from mains to the diode bridge, rather than through a 

transformer. 

The chopper stage uses a transistor, which switches on and off at high frequency to 

convert the DC current from the AC/DC converter back to an AC current for the energy transfer 

stage. A control stage drives the transistor, where the longer its on time in the duty cycle, the 

more energy is transferred. The switching frequency is in the kilohertz range, with lower 

frequencies having lower switching losses. Typically, the minimum frequency is 20 kHz, above 

the audible range of human hearing. 

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AC/DC Conversion

PWM Optocoupler

Chopper

Control Isolation

Energy Transfer +

VMains -

+

VOut

-

Figure 3.16 Simplified Circuit Diagram of a Flyback Switching Regulator 

The energy transfer stage consists of a choke, a capacitor, and a diode. The choke is 

similar to a transformer and has the same symbol in the circuit diagram. One difference is that a 

transformer in a line-frequency EPS is designed to pass energy from one winding to another with 

minimal energy storage, while a choke in a switched-mode EPS is designed to store and release 

energy. Also, the phasing of the windings is not important in the line-frequency transformer, but 

it is critically important in the flyback switching regulator. This is represented in Figure 3.16 by 

dots on the choke. 

When the chopper switch is closed, the primary winding of the choke takes energy from 

the chopper and stores the energy in the choke. When the chopper switch opens, the secondary 

winding transfers that energy through the diode to the capacitor and provides the output for the 

switching regulator, electrically isolating the load from the mains. Because the choke operates at 

a high frequency, it benefits from the associated decreases in size and weight. The energy 

transfer scheme of the switching regulator is more efficient than a linear regulator, in part 

because the choke stores and returns energy with relatively low losses. 

The isolation stage typically uses an optocoupler that consists of a light source and a 

photosensitive detector. By converting the electrical feedback signal to an optical one, the 

optocoupler maintains the load electrically isolated from the mains. The detector converts the 

optical signal back to an electrical signal that it provides to the controller. 

Generally, the controller is an integrated circuit that drives the chopper with a highfrequency pulse-width-modulated (PWM) waveform. The controller monitors the EPS output 

voltage and adjusts the pulse width to increase or decrease the amount of energy transferred by 

the chopper. If the output voltage dips, the controller will increase the duty cycle, thus increasing 

the energy passed by the energy transfer stage and increasing the output voltage. Conversely, if 

the output voltage rises, the controller will decrease the duty cycle or possibly skip cycles. This 

cycle-skipping feature is especially useful when there is no load attached, because the EPS will 

only take from the mains the small amount of power it needs to power itself. 

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Instead of an IC controller, a switched-mode EPS can also use discrete components, as in 

the case of a ringing choke converter. In that topology, discrete transistors control the chopper 

and the resulting energy transfer. EPSs without ICs tend to be more common at lower output 

powers. However, without an IC, an EPS cannot offer functions such as cycle-skipping at low 

load, which can be used to decrease losses. 

Both linear-regulated and switching-regulated EPS use regulating circuits to achieve a 

stable output voltage. However, voltage is not the only output variable that can be regulated. 

Current regulation, as discussed in the following section, is a fundamental consideration in BC 

design. 

3.4.6 EPS Technology Options 

DOE considered seven technology options that may improve the efficiency of EPSs: 

Improved Transformers. In line-frequency EPSs, the transformer has the largest effect 

on efficiency. Transformer efficiency can be improved by replacing their cores and 

windings with ones made of lower-loss material or adding extra material. 

Switched-Mode Power Supply. Line-frequency EPSs may use linear regulators to 

maintain a constant output voltage. By using a switched-mode circuit architecture, a 

designer can limit both losses associated with the transformer and the regulator. The 

differences between the two EPS types are discussed in section 3.4.5.3 and section 

3.4.5.4. 

Low-Power Integrated Circuits. The efficiency of the EPS can be further improved 

by substituting low-power IC controllers, which can switch more efficiently in active 

mode and reduce power consumption in no-load mode. For instance, the IC can turn 

off its start-up current (sourced from the primary side of the power supply) once the 

output voltage is stable. In addition, when in no-load mode, the IC can turn off the 

switching transistor for extended periods of time (termed "cycle-skipping"). 

Schottky Diodes and Synchronous Rectification. Both line-frequency and switchedmode EPSs use diodes to rectify output voltage. Schottky diodes and synchronous 

rectification can replace standard diodes to reduce rectification losses, which are 

increasingly significant at low voltage. Schottky diodes have a voltage drop of 0.3– 

0.4 volts, compared to approximately 0.6 volts for standard diodes. Synchronous 

rectification (typically only used in switched-mode EPSs) further reduces losses by 

substituting transistors for the diodes. The voltage drop across the drain-to-source 

resistance of transistor is much lower than that across even a Schottky diode, leading 

to lower losses in the output rectifier. 

Low-Loss Transistors. The switching transistor dissipates energy due to its drain-tosource resistance (RDS_ON) when the current flows through the transistor to the 

transformer. Using transistors with low RDS_ON can reduce this loss. 

Resonant Switching. In addition to reducing the RDS_ON of the transistor, power 

consumption can be lowered further by the IC controller decreasing switching 

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transients through zero-voltage or zero-current switching. The power consumption of 

the transistor is influenced by the voltage across the RDS_ON and the current flowing 

through it. An IC can control the switching to minimize that voltage or current, 

although some components in addition to the IC may also be needed. 

Resonant ("Lossless") Snubbers. In switched-mode EPSs, a common snubber protects 

the switching transistor from the high voltage spike that occurs after the transistor 

turns off by dissipating that power as heat. A resonant or lossless snubber recycles 

that energy rather than dissipating it. 

3.4.7 BC Modes of Operation 

Like the design of EPSs, the design of BCs is driven by the anticipated power 

requirements and time spent in their various modes of operation. Section 325(gg)(1)(A) of 

EPCA, as modified by EISA, defines active, standby, and off modes for consumer products in 

general. (42 U.S.C. 6295(gg)(1)(A)) However, section 2 of appendix Y to 10 CFR part 43046 

(hereafter referred to as appendix Y) defines additional modes as well as redefines some of the 

EISA modes to be more applicable to BCs (as allowed under 42 U.S.C. 6295(gg)(1)(B)) 

3.4.7.1 Active or Charge Mode 

Active mode is defined as ―the condition in which an energy-using product–(I) is 

connected to a main power source; (II) has been activated; and (III) provides 1 or more main 

functions.‖ (42 U.S.C. 6295(gg)(1)(A)(i)) However, paragraph 2.i of appendix Y further 

specifies that the charger is in active mode specifically when charging a depleted battery, 

equalizing its cells,aa or ―performing other one-time or limited-time functions necessary for 

bringing the battery to the fully charged state.‖ 

3.4.7.2 Maintenance Mode 

Once the batteries have reached full charge, the BC typically enters a maintenance mode, 

intended to maintain the fully charged state of the battery, while protecting it from overcharge. 

BCs without a maintenance mode (some high-power BCs for consumer motive equipment, for 

example) either use a timer to disconnect the BC from the batteries after charging or rely on the 

user to manually disconnect. 

3.4.7.3 Standby or No-Battery Mode 

Alternatively, following a full charge, the user can remove the battery (or in the case of 

integral-battery products, the end-use product and the battery), placing the battery charger in 

standby or no-battery mode. Typically, the BC is in the mode when the application it serves is in 

use; however, the user may also place the BC in off mode, or disconnect it from mains entirely. 

aa Equalization serves to balance the voltage across each of the cells in a multi-cell battery, a process that is most 

commonly performed with large lead-acid batteries. Unbalanced cells limit charge and discharge, reducing the 

usable capacity; they can also suffer more overcharge than the other cells. 

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3.4.7.4 Other Modes and Applicability 

Appendix Y defines standby or no-battery mode as ―the condition in which (1) the battery 

charger is connected to the main electricity supply; (2) the battery is not connected to the 

charger; and (3) for battery chargers with manual on-off switches, all such switches are turned 

on.‖ However, if (1) the charger remains connected to mains, (2) the battery is removed, and (3) 

all manual on-off switches are turned off, the charger is then placed in off mode. 

Because it has purposely been disabled by the user via a switch, the BC must no longer 

perform standby-mode functions such as powering circuitry that detects the presence of a battery 

or indicates its status. It therefore has the potential to consume less energy than in standby mode. 

Finally, the user can also disconnect the charger from mains, in which case it does not consume 

any energy. 

Whether each of the modes described above apply to a particular BC depends on whether 

the battery is integral or detachable, the presence of manual on-off switches, etc. For example, 

BCs without a manual on-off switch cannot be placed in off mode, while a BC with a nonremovable AC cord and integral batteries that are not removed from the application for charging 

cannot be placed in no-battery mode. 

Nonetheless, all BCs operate in the active or charge mode by definition. This mode has 

the largest effect on the BC’s size and efficiency because the charger must be designed to 

accommodate the maximum amount of power output, which happens during active mode. While 

the requirements of the other modes factor into the design as well—as does the chemistry of the 

battery—their effects on efficiency are not as great, since they don’t affect the power handling 

components, but rather sub-circuits tasked with assessing the state of charge and ensuring safety. 

3.4.8 BC Efficiency Metrics 

On December 8, 2006, DOE adopted a test method to measure the efficiency of battery 

chargers. 71 FR 71340. This test method, based on the U.S. Environmental Protection Agency’s 

(EPA) ENERGY STAR ―Test Methodology for Determining the Energy Performance of Battery 

Charging Systems,‖ integrates the power consumed by BCs in maintenance and no-battery 

modes over fixed periods of time. This ―non-active energy‖ is divided by the battery energy, 

measured at a discharge rate of 0.2 C, resulting in an energy ratio. Normalizing by battery energy 

is meant to account for proportionally higher losses in chargers intended for higher-energy 

batteries. A higher energy ratio represents higher BC non-active energy consumption. 

However, in the December 8, 2006, Test Procedure Final Rule, DOE stated that it 

intended to study further BC active mode energy consumption and reserved a section in the test 

procedure (section 4(b) of appendix Y to subpart B of 10 CFR Part 430) to cover measurement 

of active mode energy consumption. 71 FR 71340, 71360. DOE has continued developing its 

approach for measuring BC active—i.e., charging—mode energy consumption and on April 2, 

2010published a proposal for adopting an active mode test procedure based on a test procedure 

previously adopted by the California Energy Commission. 75 FR 16958. 

If adopted, this proposed amendment would stop use of the non-active energy ratio in 

favor of metrics corresponding to energy consumption in each of the energy-consuming modes 

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of operation of a BC. As described above, these include active, maintenance, standby, and off 

modes; thus, the test procedure would return four separate metrics. These separate metrics would 

then be weighted by an average usage profilebb that reflects the typical usage of BCs in each 

product class. For the analysis in this preliminary TSD, DOE used these metrics to evaluate BC 

efficiency. 

The potential energy conservation standards for each class would likewise be written in 

terms of a single metric, even though the test procedure would measure consumption in each of 

the modes separately. Manufacturers would then be free to trade off power consumption in one 

mode for that in another, as long as they meet the usage-weighted energy consumption required 

by the standard. 

3.4.9 Battery Charger Design 

The design of a battery charger depends on the application it serves, and as mentioned in 

the discussion of product classes in section 3.3, specifically its voltage and energy requirements. 

As a result, the design of battery chargers varies with product class, which is defined by battery 

voltage and energy. Therefore, following a brief introduction, this section will be divided by 

product class. 

A general schematic of a battery charging system (BC and battery) can be seen in Figure 

3.17. As indicated in the figure, the primary function of a BC is regulating the flow of current 

from a power supply to a battery to safely charge the battery and maintain its charge. 

Battery Charger Rechargeable 

+

VBatt

-

+ 

-

RSupply IOut

VSupply 

Charge 

Regulator 

Power Supply Battery 

+ 

Electrochemical 

Process 

-

Figure 3.17 General schematic of a BC and battery. 

As depicted in Figure 3.17, the first stage of most BCs is a power supply that converts 

line-voltage AC power to DC power at a voltage low enough to charge the battery (through a 

charge regulator) as well as power any overhead circuitry in the charger responsible for safety 

and other user function (e.g., status indicators, etc.; not pictured in the figure). Because of this 

general AC/DC conversion requirement, the design of the input power supply stage often mimics 

bb The calculation of product-class-average usage profiles and the calculation of typical energy consumption is 

described in detail in the energy use analysis (chapter 7). 

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that of the EPSs described in section 3.4.5, in particular unregulated line-frequency AC/DC and 

various switched-mode AC/DC designs, including flyback. This power supply stage can be either 

internal (i.e., in the same enclosure as the rest of the BC circuitry) or in an external wall adapter. 

Although the circuits are similar, the key difference between an EPS and a BC is charge control. 

An EPS is designed to provide output current so as to maintain a constant output voltage to the 

load. In contrast, a BC provides power to a battery that may either be constant current or constant 

voltage, depending on the state of the battery. Further, a battery sets a voltage in the BC circuit, 

whereas a load does not set a voltage for an EPS. 

Methods of improving BC efficiency depend on whether the BC is a slow charger or a 

fast charger. The distinction between the two types of BCs is based on the charge rate (also 

referred to as C-rate), often defined as the average charging current flowing into the battery, 

divided by the nominal battery charge capacity. For current expressed in amperes and battery 

capacity expressed in ampere-hours, the resulting quantity is expressed in units of 1/hours or C. 

For example, a BC with a 0.1 ampere (A) output current charging a 1 ampere-hour (Ah) battery 

would result in a charge rate of 0.1 C. Charging time is approximately the inverse of the charge 

rate, adjusted for the efficiency of the battery itself, which varies with chemistry. In the previous 

example, the battery would take slightly longer than 10 hours to charge. 

DOE considers BCs with charge rates less than 0.2 C (typically around 0.1 C) to be slow 

chargers. At this low charge rate, nickel-based batteries can be charged continuously without 

concern for excessive battery overheating or safety. Slow chargers do not typically include cutoff 

or monitoring circuitry. However, as the battery nears full charge and its voltage increases, the 

difference between the BC output and battery voltages decreases and the charge-control 

resistance used in a slow charger will cause the charging current to decrease. This reduces power 

consumption and lessens battery heating due to overcharge (thereby extending battery life). Slow 

chargers are not typically used in combination with lithium-based batteries, because of the safety 

concerns associated with overcharging lithium-based batteries. 

Slow chargers are typically composed of a line-frequency transformer followed by a 

rectifier and charge-control element. The function of the charge-control element is to limit 

charging current into the battery, which can be accomplished by either a discrete resistor or the 

parasitic internal resistance of the transformer windings. The power conversion losses in a slow 

charger are mostly due to magnetization losses in the transformer core steel, resistive losses in 

the charge-control element, and voltage drops across the rectifier diodes. 

In addition, slow chargers typically continue to deliver current to the battery even after it 

is fully charged, usually at a rate much higher than that necessary to maintain the charge lost due 

to battery self-discharge. The excess power is dissipated as heat in the battery. The power 

conversion losses in the BC identified earlier continue to have an impact in this maintenance 

mode, further increasing power consumption. Even in no-battery mode, when the battery is 

disconnected from the charger, the slow charger continues to consume significant power due to 

the transformer magnetization losses. For a detailed discussion of slow-charger power 

consumption in all modes, please see sections 3.3 and 3.5 of the draft technical report that 

accompanied the Framework Document published on June 4, 2009. 74 FR 26816. 

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A battery charger that contains monitoring, cutoff, or limiting circuitry can safely charge 

lithium-based batteries and fast-charge nickel-based batteries. DOE considers BCs with charge 

rates greater than 0.2 C (typically between 0.6 C and 1 C) to be fast chargers. Because the charge 

rate of fast chargers is much greater than that of slow chargers, the maximum rated output power 

of a fast charger can be 5 to 20 times greater than that of slow chargers, even when charging a 

battery of the same voltage and capacity. For this reason, fast chargers typically use switchedmode power supplies, which are smaller and lighter than line-frequency power supplies. Fast 

chargers also employ monitoring and cutoff circuitry, as the high currents used during charging 

may overheat the battery and lead to a safety hazard if not reduced at the proper time. Because of 

these design differences, fast chargers are composed of more complex circuits and are 

susceptible to different loss mechanisms than slow chargers. 

The high-frequency switched-mode power supply (whether internal or external) that 

typically performs the energy conversion in a fast charger is usually more efficient than the linefrequency transformer and rectifier discussed previously. High-frequency power supplies can use 

transformer cores made of ferrite that are smaller and more efficient than the steel cores typically 

found in line-frequency designs. However, there are still conversion losses associated with 

switching and rectification, as well as fixed overhead losses associated with powering the 

integrated circuit (IC) switching controller and any safety circuitry. Also, although fast chargers 

terminate (i.e., limit charging current once the battery has reached full charge), most chargers 

continue to supply a small amount of maintenance current. As with slow chargers, this 

maintenance current and the associated conversion losses contribute heavily to maintenancemode power consumption. Finally, even with the battery removed, the charger can continue 

consuming significant power due to the overhead of powering the control and safety circuitry 

mentioned above. For a more detailed discussion of fast-charger power consumption, please see 

sections 3.3 and 3.5 of the draft technical report. 

Further, manufacturers may, and often do, choose to substitute a fast charger for a slow 

one as a means of improving portability and energy efficiency. Because both types of chargers 

can often be used with the same battery powering the same consumer product, they provide the 

same utility to the consumer, which sometimes means the fast charger can be considered as a 

replacement for a slow charger. 

Finally, because changes in battery temperature and voltage happen more slowly at lower 

charge rates, monitoring circuitry that depends on these changes to stop the charging process is 

typically not sensitive enough to be used at rates below 0.3 C. Therefore, although DOE 

differentiates between BCs with charge rates greater than or less than 0.2 C, DOE does not 

expect to find many BCs with charge rates between 0.15 C and 0.3 C. 

3.4.10 Battery Charger Technology Options 

Battery charger efficiency in active mode is governed by BC component losses and 

overhead circuitry. BCs share with EPSs similar options for reducing component losses in active 

mode. However, some BCs have safety circuitry to monitor the battery during charging, which 

EPSs typically do not include. Safety circuits are often present in BCs that are fast chargers; 

safety concerns also affect design of slow charging BCs. Thus, if a BC were compared to an EPS 

with similar power ratings, it might appear to have lower conversion efficiency due to the 

additional power consumption of its safety circuitry. 

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The following list, organized by charger type, provides preliminary technology options 

that DOE intends to evaluate during the preliminary analyses. A detailed discussion of the 

specific technology options can be found in section 3.8.2 of the draft technical report. Although 

many of these technology options could be used in both fast and slow chargers, doing so may be 

impractical due to the cost and benefits of each option for the two types of chargers. Therefore, 

in the list below, the options are grouped with the charger type where they would be most 

practical. 

Slow charger technology options include: 

Improved Cores: The efficiency of line-frequency transformers, which are a 

component of the power conversion circuitry of many slow chargers, can be 

improved by replacing their cores with ones made of lower-loss steel. 

Termination: Substantially decreasing the charge current to the battery after it has 

reached full charge, either by using a timer or sensor, can significantly decrease 

maintenance-mode power consumption. Because most slow chargers have a charge 

rate of approximately 0.1 C, and maintenance-mode current below 0.05 C is typically 

sufficient to keep a battery fully charged, a slow charger that employs termination can 

roughly halve its maintenance-mode power consumption. 

Elimination/Limitation of Maintenance Current: Constant maintenance current is not 

required to keep a battery fully charged. Instead, the BC can provide current pulses to 

"top off" the battery as needed. Elimination or limitation of maintenance can decrease 

maintenance-mode power consumption even further and has the added benefit of 

extending the battery lifetime by reducing heating due to overcharge. 

Elimination of No-Battery Current: A mechanical AC line switch inside the battery 

charger "cup" automatically disconnects the BC from the mains supply when the 

battery is removed from the charger. Although manual (i.e., user-controlled) switches 

are also possible, this method guarantees that the BC ceases to consume power once 

the battery is removed from the battery charger. 

Switched-Mode Power Supply: To increase efficiency, line-frequency power supplies 

can be replaced with switched-mode EPSs, which greatly reduce the biggest sources 

of loss in a line-frequency EPS: the transformer. Because a switched-mode EPS 

operates at high frequency (greater than 20 kHz), its transformer can be smaller, and 

because transformer losses are a function of volume, a smaller transformer is usually 

more efficient. It is worth noting that this technology option is not often found in 

practice, because the inclusion of a switched-mode power supply within the BC 

design allows the higher power levels necessary for fast charging. The universal 

consumer preference for shorter charging times limits the occurrence of slow chargers 

with high-frequency switched-mode power supplies. 

Fast charger technology options include: 

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Low-Power Integrated Circuits: The efficiency of the BC's switched-mode power 

supply can be further improved by substituting low-power IC controllers, which can 

switch more efficiently in active mode and reduce power consumption in no-load 

mode. To increase efficiency in active mode, the IC controller can decrease switching 

transients through zero-voltage or zero-current switching. Furthermore, the IC can 

turn off its start-up current (sourced from the primary side of the power supply) once 

the output voltage is stable. In addition, when in no-load mode, the IC can turn off the 

switching transistor for extended periods of time (termed "cycle-skipping"). 

Elimination/Limitation of Maintenance Current: See above. 

Schottky Diodes and Synchronous Rectification: Both line-frequency and switchedmode EPSs use diodes to rectify output voltage. Schottky diodes and synchronous 

rectification can replace standard diodes to reduce rectification losses, which are 

increasingly significant at low voltage. Schottky diodes are rectifiers constructed 

from a metal-silicon junction rather than a p-n silicon junction and have a voltage 

drop of 0.3–0.4 volts, compared to approximately 0.6 volts for standard p-n junction 

diodes. Synchronous rectification (which is typically used only in switched-mode 

EPSs) further reduces losses by substituting field-effect transistors (FETs) for the 

diodes. The voltage drop across the drain-to-source resistance of the FET is much 

lower than that of a Schottky diode, leading to lower losses in the output rectifier. 

Elimination of No-Battery Current: See above. 

Phase Control to Limit Input Power: Even when a typical BC is not delivering its 

maximum output current to the battery, its power conversion circuitry continues to 

draw significant power. A phase control circuit, like the one present in most common 

light dimmers, can be added to the primary side of the BC power supply circuitry to 

limit input current in lower-power modes. 

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REFERENCES
 

1 Consumer Electronics Association Market Research Department. U.S. Consumer Electronics Sales and Forecasts
 

2005-2010. July 2009. Consumer Electronics Association: Arlington, VA.
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September 13, 2010.)
 

<http://www.appleinsider.com/articles/07/05/11/apple_snags_10_percent_of_u_s_retail_notebook_sales_in_march.
 

html.> The September 13, 2010 material from this website is available in Docket # EERE-2008-BT-STD-0005. For
 

more information, contact Ms. Brenda Edwards at (202) 586-2945.
 3 RocketFish. Digital Wireless Speakers. 2008. Available at: 

<http://www.rocketfishproducts.com/cms/documents/RF-WS01_WS02_WS02-W_08-1669_ENGLISH_WEB.pdf>
 4 U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy. FY2005 Preliminary PrioritySetting Summary Report and Actions Proposed. Appendix A: FY2005 Technical Support Document. Table A9-1:
 

Background Data on Battery Chargers and Power Supplies.
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2010.) <http://news.cnet.com/8301-1001_3-10285189-92.html?tag=mncol> The July 15, 2010 material from this
 

website is available in Docket # EERE-2008-BT-STD-0005. For more information, contact Ms. Brenda Edwards at 

(202) 586-2945.
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<http://www.eetasia.com/ART_8800456083_499486_NT_67de3825.HTM> The September 13, 2010 version of this
 

website is available in Docket # EERE-2008-BT-STD-0005. For more information, contact Ms. Brenda Edwards at 

(202) 586-2945.
 7 World Bank. Gross domestic product 2008. 2009. Available at: 

<http://siteresources.worldbank.org/DATASTATISTICS/Resources/GDP.pdf> 8 Global Industry Analysts. Uninterruptible Power Supply Systems. May 2008. Report MCP-1120.
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 10 Masterson, Michele. Printer Market Q4 2008: News That Isn't Fit To Print. ChannelWeb. March 16, 2009. (Last 

accessed September 13, 2010.)
 

<http://www.crn.com/hardware/215900485;jsessionid=M1XEH1PUFGCELQE1GHPCKH4ATMY32JVN> The 

September 13, 2010 version of this website is available in Docket # EERE-2008-BT-STD-0005. For more 

information, contact Ms. Brenda Edwards at (202) 586-2945.
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accessed September 13, 2010.) <http://www.echannelline.com/usa/story.cfm?item=25239> The September 13, 2010
 

version of this website is available in Docket # EERE-2008-BT-STD-0005. For more information, contact Ms. 

Brenda Edwards at (202) 586-2945.
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America supplement prepared for DOE.
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2010.) <http://www.rcrwireless.com/article/20090119/WIRELESS/901199989/1080/bluetooth-adoption-set-forcontinued-expansion> The September 13, 2010 version of this website is available in Docket # EERE-2008-BTSTD-0005. For more information, contact Ms. Brenda Edwards at (202) 586-2945.
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<http://www.itfacts.biz/240-mln-gps-enabled-phones-to-sell-in-2009/12494> The September 13, 2010 version of
 

this website is available in Docket # EERE-2008-BT-STD-0005. For more information, contact Ms. Brenda 

Edwards at (202) 586-2945.
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<http://www.itfacts.biz/500-mln-music-phones-shipped-in-2007/10294> The September 13, 2010 version of this
 

website is available in Docket # EERE-2008-BT-STD-0005. For more information, contact Ms. Brenda Edwards at 

(202) 586-2945.
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<http://www.gsmworld.com/our-work/mobile_planet/universal_charging_solution.htm> The September 13, 2010
 

version of this website is available in Docket # EERE-2008-BT-STD-0005. For more information, contact Ms. 

Brenda Edwards at (202) 586-2945.
 

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17 IT Facts. Americans discard 125 mln phones annually. 2008. (Last accessed September 13, 2010.) 

<http://www.itfacts.biz/americans-discard-125-mln-phones-annually/10093> The September 13, 2010 version of 

this website is available in Docket # EERE-2008-BT-STD-0005. For more information, contact Ms. Brenda 

Edwards at (202) 586-2945. 

18 GSM World. ―Mobile Industry Unites to Drive Universal Charging Solution for Mobile Phones‖. 2009. (Last 

accessed September 13, 2010.) <http://www.gsmworld.com/newsroom/press-releases/2009/2548.htm> The 

September 13, 2010 version of this website is available in Docket # EERE-2008-BT-STD-0005. For more 

information, contact Ms. Brenda Edwards at (202) 586-2945. 

19 Shambora, Jessica. Consumers Flip for Mini Camcorders. CNN Money. January 27, 2009. (Last accessed 

September 13, 2010.) <http://money.cnn.com/2009/01/27/technology/flip_cams.fortune/> The September 13, 2010 

version of this website is available in Docket # EERE-2008-BT-STD-0005. For more information, contact Ms. 

Brenda Edwards at (202) 586-2945. 20 Clairmont, Kristy. PMA Data Watch: Purchasing of cameras and accessories. April 2009. (Last accessed 

September 13, 2010.) <http://pmaforesight.com/?p=155> The September 13, 2010 version of this website is 

available in Docket # EERE-2008-BT-STD-0005. For more information, contact Ms. Brenda Edwards at (202) 586­

2945. 

21 th 56 Annual Report: Statistical Review. Appliance Magazine. 2009. 66 (4): pp 34-37. 22 iRobot Corporation. 2008 iRobot Annual Report. 2009. Bedford, MA. Report No. 000-51598 23 Kaiser, Sheryl. Child Safety Gate. (Last accessed July 15, 2010.) 

<http://www.firstbabymall.com/product/gate.htm> The July 15, 2010 version of this website is available in Docket # 

EERE-2008-BT-STD-0005. For more information, contact Ms. Brenda Edwards at (202) 586-2945. 24 Orland, Kyle. February NPD data shows DS, Wii on top. March 16, 2007. (Last accessed July 14, 2010.) 

<http://www.joystiq.com/2007/03/16/february-npd-data-show-ds-wii-on-top/> The July 14, 2010 version of this 

website is available in Docket # EERE-2008-BT-STD-0005. For more information, contact Ms. Brenda Edwards at 

(202) 586-2945.
 25 R. Neugebauer, B. Frazer, P. May-Ostendorp, C. Calwell, Ecos Consulting. Lowering the Cost of Play: Improving
 

the Energy Efficiency of Video Game Consoles. 2008. Natural Resources Defense Council: New York, NY.
 26 th Appliance Magazine. 56 Annual Industry Forecast. January, 2008. 65 (1): pp 38. 27 Saxman, Donald. Portable Battery Powered Products: Global Markets. 2008. BCC Research: Wellesley, MA. 

Report No. FCB023D 

28 American Pet Products Manufacturers Association. 2007-2008 national Pet Owners Survey. Quoted in: The Pet 

Haven. Pet Ownership Statistics. July 18, 2007. (Last accessed September 13, 2010.) <http://the-pethaven.blogspot.com/2007/07/pet-ownership-statistics.html> The September 13, 2010 version of this website is 

available in Docket # EERE-2008-BT-STD-0005. For more information, contact Ms. Brenda Edwards at (202) 586­

2945. 

29 Graystone Creations. Frequently Asked Questions. (Last accessed July 15, 2010.) 

<http://www.graystonecreations.com/definitions.htm> The July 15, 2010 version of this website is available in 

Docket # EERE-2008-BT-STD-0005. For more information, contact Ms. Brenda Edwards at (202) 586-2945. 30 Southwest Garden Arts. FAQ. February 26, 2008. (Last accessed July, 14 2010.) 

<http://www.arizonafountains.com/FAQ.htm> The July 14, 2010 version of this website is available in Docket # 

EERE-2008-BT-STD-0005. For more information, contact Ms. Brenda Edwards at (202) 586-2945. 31 nd Appliance Magazine. 32 Annual Portrait of the U.S. Appliance Industry. September, 2009. p. 34. 32 Teschke, D. A., P. Goldman, N. Levy, T. Goodman. Housewares MarketWatch. Fall 2007. International 

Housewares Association: Rosemont, IL. Report No. 091707A/18M 

33 Teschke, D. A., P. Goldman, J. Marshall-Bolton, T. Goodman. Housewares MarketWatch. Summer 2009. 

International Housewares Association: Rosemont, IL. 

34 Berner, Robert. Why P&G’s Smile is So Bright. Business Week. August 12, 2002. (Last accessed September 13, 

2010.) <http://www.businessweek.com/magazine/content/02_32/b3795072.htm> The September 13, 2010 version of 

this website is available in Docket # EERE-2008-BT-STD-0005. For more information, contact Ms. Brenda 

Edwards at (202) 586-2945. 

35 Toy Industry Association, Inc. State of the Industry. (Last accessed September 13, 2010.) 

<http://www.toyassociation.org/AM/Template.cfm?Section=12_Rolling_Months> The September 13, 2010 version 

of this website is available in Docket # EERE-2008-BT-STD-0005. For more information, contact Ms. Brenda 

Edwards at (202) 586-2945. 

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36 International Market Solutions. Golf Car-Type Vehicles and the Emerging Market for Small, Task-Oriented
 

Vehicles in the United States. December 2007.
 37 Toy Industry Association. State of the U.S. Toy Industry Rolling Report. July 2009.
 38 United States Census Bureau. U.S. Population Projections. 2008.
 39 New York Times. Goodman, David. "An Electric Boost for Bicyclists" February 1, 2010. (Last accessed
 

September 13, 2010.) <http://www.nytimes.com/2010/02/01/business/global/01ebike.html?pagewanted=all#> The 

September 13, 2010 version of this website is available in Docket # EERE-2008-BT-STD-0005. For more 

information, contact Ms. Brenda Edwards at (202) 586-2945.
 40 Marketstrat, Inc. Total Powered Mobility Aids Market - United States (2004 - 2012). 2006.
 41 Global Industry Analysts, Inc. Wheelchairs (Powered and Manual). March 2008.
 42 U.S. Department of Energy. Draft Technical Report Energy Conservation Program for Consumer Products: 

Battery Chargers and External Power Supplies. May 2009. Available at: 

http://www1.eere.energy.gov/buildings/appliance_standards/residential/pdfs/bceps_draft_tech_report.pdf
 43 US Environmental Protection Agency. Energy Star External Power Supply Qualified Products. September 2009.
 44 Lawrence Berkeley National Laboratory. Climate Change Action Plan August 2009 Update. August, 2009.
 45 Darnell Group, Inc. External AC-DC Power Supplies Second Edition. August 2005.
 46 Title 10—Energy, Chapter II—Department of Energy, Part 430—Energy Conservation Program for Consumer
 

Products, Subpart B—Test Procedures.
 

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CHAPTER 4. SCREENING ANALYSIS 

TABLE OF CONTENTS 

4.1 INTRODUCTION ........................................................................................................... 4-1
 

4.2 SCREENED OUT EPS TECHNOLOGY OPTIONS ..................................................... 4-2
 

4.3 REMAINING EPS DESIGN OPTIONS ......................................................................... 4-2
 

4.4 SCREENED OUT BC TECHNOLOGY OPTIONS ....................................................... 4-2
 

4.5 REMAINING BC DESIGN OPTIONS........................................................................... 4-3
 

LIST OF TABLES 

TABLE 4.1 EXTERNAL POWER SUPPLY DESIGN OPTIONS ............................................ 4-2
 

TABLE 4.2 SCREENED OUT BATTERY CHARGER TECHNOLOGY OPTIONS.............. 4-3
 

TABLE 4.3 BATTERY CHARGER DESIGN OPTIONS.......................................................... 4-3
 

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CHAPTER 4. SCREENING ANALYSIS
 

4.1 INTRODUCTION 

This chapter discusses the U.S. Department of Energy’s (DOE’s) screening analysis of the 

technology options identified for battery chargers (BC) and external power supplies (EPS). As 

discussed in chapter 3 of the preliminary technical support document (TSD), DOE consults with 

industry, technical experts, and other interested parties to develop a list of technology options for 

consideration. The purpose of the screening analysis is to determine which options to consider 

further and which to screen out. 

Section 325(o)(2) of the Energy Policy and Conservation Act (EPCA) provides that any 

new or revised standard must be designed to achieve the maximum improvement in energy 

efficiency that is determined to be technologically feasible and economically justified. (42 

U.S.C. 6295(o)(2)) In view of the EPCA requirements appendix A to subpart C of title 10, Code 

of Federal Regulations (CFR), part 430 (10 CFR part 430), Procedures, Interpretations, and 

Policies for Consideration of New or Revised Energy Conservation Standards for Consumer 

Products (the Process Rule) sets forth procedures to guide DOE in its consideration and 

promulgation of new or revised efficiency standards. These procedures elaborate on the statutory 

criteria provided in 42 U.S.C. 6295(o) and, in part, eliminate problematic technologies early in 

the process of prescribing or amending an energy efficiency standard. In particular, sections 

4(b)(4) and 5(b) of the Process Rule provide guidance to DOE for determining which design 

options are unsuitable for further consideration: 

1.	 Technological feasibility. DOE will consider technologies incorporated in commercial 

products or in working prototypes to be technologically feasible. 

2.	 Practicability to manufacture, install, and service. If mass production and reliable 

installation and servicing of a technology in commercial products could be achieved on 

the scale necessary to serve the relevant market at the time the standard comes into effect, 

then DOE will consider that technology practicable to manufacture, install, and service. 

3.	 Adverse impacts on product utility or product availability. If DOE determines a 

technology would have significant adverse impact on the utility of the product to 

significant subgroups of consumers, or would result in the unavailability of any covered 

product type with performance characteristics (including reliability), features, sizes, 

capacities, and volumes that are substantially the same as products generally available in 

the United States at the time, it will not consider this technology further. 

4.	 Adverse impacts on health or safety. If DOE determines that a technology will have 

significant adverse impacts on health or safety, it will not consider this technology 

further. 

Section 4.2 discusses the EPS technology options DOE screened out from further 

consideration. Section 4.3 lists the remaining design options DOE considered in its analyses. 

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4.2 SCREENED OUT EPS TECHNOLOGY OPTIONS 

DOE did not screen out any technology options, having considered the following four 

factors: (1) technological feasibility; (2) practicability to manufacture, install, and service; (3) 

adverse impacts on product utility to consumers; and (4) adverse impacts on health or safety. 

4.3 REMAINING EPS DESIGN OPTIONS 

DOE is considering the design options in Table 4.1 as viable means for improving EPS 

efficiency. Chapter 3 provides a detailed description of these design options, which DOE will 

consider in the engineering analysis (chapter 5). 

Table 4.1 External Power Supply Design Options 

Technology Option Description 

Improved Transformers Use transformers with low losses. 

Switched-Mode Power Supply Use switched-mode power supplies instead of 

linear power supplies. 

Low-Power Integrated Circuits Use integrated circuit controllers with minimal 

power consumption. 

Schottky Diodes and Synchronous 

Rectification 

Use rectifiers with low losses. 

Low-Loss Transistors Use transistors with low drain-to-source 

resistance. 

Resonant Switching Use an algorithm to turn on the transformer 

only when losses are minimal. 

Resonant ("Lossless") Snubbers Reuse energy sent to the snubber. 

4.4 SCREENED OUT BC TECHNOLOGY OPTIONS 

This section addresses the BC technologies that DOE screened out, having considered the 

following factors: (1) technological feasibility; (2) practicability to manufacture, install, and 

service; (3) adverse impacts on product utility to consumers; and (4) adverse impacts on health 

or safety. 

DOE examined all of the technology options presented in the technology assessment. The 

table below lists out the options that DOE decided to screen out and which criterion that 

technology option failed to meet: 

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Table 4.2 Screened Out Battery Charger Technology Options 

Technology Option Failed Screening Criterion 

Lowering charging current or increasing 

voltage 

Adverse impacts on product utility to 

consumers 

Capacitive reactance Adverse impacts on safety 

Non-inductive chargers for toothbrush and 

other wet applications 

Adverse impacts on safety 

4.5 REMAINING BC DESIGN OPTIONS 

After screening out the aforementioned technology options in accordance with the policies 

set forth in 10 CFR Part 430, Subpart C, Appendix A, (4)(a)(4) and 5(b), DOE is considering the 

design options in Table 4.3 as viable means for improving battery charger efficiency. Chapter 3 

provides a detailed description of these design options, which DOE will consider in the 

engineering analysis (chapter 5). 

Table 4.3 Battery Charger Design Options 

Technology Option Description 

Slow charger 

Improved Cores Use transformer cores with low losses. 

Termination Limit power provided to fully-charged 

batteries. 

Elimination/Limitation of 

Maintenance Current 

Limit power provided to fully-charged 

batteries. 

Elimination of No-Battery Current Limit power provided drawn when no 

battery is present. 

Switched-Mode Power Supply Use switched-mode power supplies instead 

of linear power supplies. 

Fast charger 

Low-Power Integrated Circuits Use integrated circuit controllers with 

minimal power consumption. 

Elimination of No-Battery Current Limit power provided drawn when no 

battery is present. 

Schottky Diodes and Synchronous 

Rectification 

Use rectifiers with low losses. 

Elimination of No-Battery Current Limit power provided drawn when no 

battery is present. 

Phase Control to Limit Input 

Power 

Limit input power in lower-power modes. 

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CHAPTER 5. ENGINEERING ANALYSIS
 

TABLE OF CONTENTS 

CHAPTER 5. ENGINEERING ANALYSIS .............................................................................. 5-1
 

5.1	 Introduction.......................................................................................................... 5-1
 

5.2	 Engineering Analysis Methodology .................................................................... 5-1
 

5.3	 Market Survey to Select Represenative Units ..................................................... 5-3
 

5.4	 Class A External Power Supply Engineering Analysis ....................................... 5-8
 

5.4.1	 Class A EPS Representative Product Classes and Representative Units. 5-8
 

5.4.2	 Candidate Standard Levels for Representative Product Class A1 ......... 5-10
 

5.4.3	 Class A EPS Testing Analysis ............................................................... 5-16
 

5.4.4	 Class A EPS Teardowns to Estimate Manufacturer Production Cost.... 5-24
 

5.4.5	 Class A EPS Manufacturer Interviews .................................................. 5-26
 

5.4.6	 Class A EPS Scaling Relationships ....................................................... 5-36
 

5.4.7	 Class A EPS Cost and Efficiency Relationships from Testing and 

Teardowns.............................................................................................. 5-52
 

5.4.8	 Class A EPS Cost and Efficiency Relationships from Manufacturer 

Interviews............................................................................................... 5-54
 

5.4.9	 Summary of Results for Class A EPSs .................................................. 5-57
 

5.4.10 Creating Class A EPS CSL Equations for All Product Classes Based On 

the Representative Units ........................................................................ 5-63
 

5.5	 Non-Class A External Power Supply Engineering Analysis ............................. 5-68
 

5.5.1	 Non-Class A EPS Representative Product Classes and Representative
 

Units....................................................................................................... 5-68
 

5.5.2	 Non-Class A EPS Candidate Standard Levels of Efficiency................. 5-71
 

5.5.3	 Developing Cost-Efficiency Results for NCA EPSs ............................. 5-74
 

5.6	 Battery Charger Engineering Analysis .............................................................. 5-75
 

5.6.1	 BC Representative Product Classes....................................................... 5-75
 

5.6.2	 BC Representative Units........................................................................ 5-78
 

5.6.3	 BC Candidate Standard Levels of Efficiency ........................................ 5-82
 

5.6.4	 BC Teardown Analysis .......................................................................... 5-84
 

5.6.5	 BC Manufacturer Interviews.................................................................. 5-85
 

5.6.6	 BC Cost Model ...................................................................................... 5-92
 

5.6.7	 BC Scaling from Representative Units to Product Classes ................... 5-94
 

5.6.8	 Representative Product Class 1: Low Energy, Inductive....................... 5-96
 

5.6.9	 Representative Product Class 2: Low Energy, Low Voltage............... 5-101
 

5.6.10 Representative Product Class 4: Low Energy, High Voltage .............. 5-113
 

5.6.11 Representative Product Class 5: Med. Energy, Low Voltage.............. 5-125
 

5.6.12 Representative Product Class 7: High Energy..................................... 5-135
 

5.6.13 Representative Product Class 10: Low Energy, AC Output................ 5-139
 

5.6.14 Extending the Analysis to Product Classes not Analyzed Directly ..... 5-148
 

5.6.14.4 Scaled Product Class 9: Low Energy, 12 V DC Input............. 5-153
 

5-i 

EERE-2008-BT-STD-0005 COMMENT 31
 

LIST OF TABLES
 

TABLE 5.1 PROPOSED EPS REPRESENTATIVE PRODUCT CLASS AND SCALED 

PRODUCT CLASSES..................................................................................................... 5-8
 

TABLE 5.2 EVALUATION OF POTENTIAL LOW-POWER EPSS AS REPRESENTATIVE 

TABLE 5.4 CANDIDATE STANDARD LEVELS OF EFFICIENCY FOR PRODUCT CLASS
 

TABLE 5.5 BASELINE (CSL0) EISA 2007 ACTIVE MODE EFFICIENCY FOR PRODUCT 

TABLE 5.6 BASELINE (CSL0) EISA 2007 NO-LOAD POWER CONSUMPTION FOR 

TABLE 5.7 CSL1 ENERGY STAR 2.0 ACTIVE MODE EFFICIENCY FOR PRODUCT 

TABLE 5.8 CSL1 ENERGY STAR 2.0 NO-LOAD MODE POWER CONSUMPTION FOR 

TABLE 5.9 CSL 2 INTERMEDIATE ACTIVE-MODE EFFICIENCY FOR PRODUCT CLASS
 

TABLE 5.10 CSL 2 INTERMEDIATE NO-LOAD MODE POWER CONSUMPTION FOR 

TABLE 5.11 CSL3 BEST IN MARKET ACTIVE MODE EFFICIENCY FOR PRODUCT 

TABLE 5.12 CSL3 BEST IN MARKET NO-LOAD MODE POWER CONSUMPTION FOR 

TABLE 5.13 CSL4 MAX TECH ACTIVE MODE EFFICIENCY FOR PRODUCT CLASS A1
 

TABLE 5.14 CSL4 MAX TECH NO-LOAD MODE POWER CONSUMPTION FOR 

TABLE 5.20 CURVES CHARACTERIZING THE RELATIONSHIP BETWEEN OUTPUT 

TABLE 5.21 EFFECTS OF A 1.66M OUTPUT CORD ON EPS EFFICIENCY IN 

TABLE 5.24 COST AND EFFICIENCY RELATIONSHIP FOR 2.5W EPS (TESTING AND
 

TABLE 5.25 COST AND EFFICIENCY RELATIONSHIP FOR 18W EPS (TESTING AND
 

TABLE 5.26 COST AND EFFICIENCY RELATIONSHIP FOR 60W EPS (TESTING AND
 

UNITS.............................................................................................................................. 5-9
 

TABLE 5.3 EXTERNAL POWER SUPPLY REPRESENTATIVE UNITS ........................... 5-10
 

A1................................................................................................................................... 5-10
 

CLASS A1 ..................................................................................................................... 5-12
 

PRODUCT CLASS A1.................................................................................................. 5-12
 

CLASS A1 ..................................................................................................................... 5-13
 

PRODUCT CLASS A1.................................................................................................. 5-13
 

A1................................................................................................................................... 5-14
 

PRODUCT CLASS A1.................................................................................................. 5-14
 

CLASS A1 ..................................................................................................................... 5-14
 

PRODUCT CLASS A1.................................................................................................. 5-15
 

........................................................................................................................................ 5-16
 

PRODUCT CLASS A1.................................................................................................. 5-16
 

TABLE 5.15 2.5-WATT UNITS USED TO CHARACTERIZE THE CSLS .......................... 5-20
 

TABLE 5.16 18-WATT UNITS USED TO CHARACTERIZE THE CSLS ........................... 5-21
 

TABLE 5.17 60-WATT UNITS USED TO CHARACTERIZE THE CSLS ........................... 5-22
 

TABLE 5.18 120-WATT UNITS USED TO CHARACTERIZE THE CSLS ......................... 5-24
 

TABLE 5.19 ISUPPLI TEARDOWN COST ESTIMATES..................................................... 5-26
 

VOLTAGE AND EFFICIENCY................................................................................... 5-45
 

PERCENTAGE POINTS .............................................................................................. 5-48
 

TABLE 5.22 AVERAGE OUTPUT CORD LENGTHS .......................................................... 5-49
 

TABLE 5.23 SCALING AND MARKUP STEPS PERFORMED ON THE TEST UNITS .... 5-53
 

TEARDOWNS) ............................................................................................................. 5-53
 

TEARDOWNS) ............................................................................................................. 5-54
 

TEARDOWNS) ............................................................................................................. 5-54
 

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TABLE 5.27 COST AND EFFICIENCY RELATIONSHIP FOR 120W EPS (TESTING AND
 

TEARDOWNS) ............................................................................................................. 5-54
 

TABLE 5.28 SCALING AND MARKUP STEPS PERFORMED ON THE AGGREGATED 

TABLE 5.29 COST AND EFFICIENCY RELATIONSHIP FOR 2.5W EPS
 

TABLE 5.30 COST AND EFFICIENCY RELATIONSHIP FOR 18W EPS
 

TABLE 5.31 COST AND EFFICIENCY RELATIONSHIP FOR 60W EPS
 

TABLE 5.32 COST AND EFFICIENCY RELATIONSHIP FOR 120W EPS
 

TABLE 5.33 ACTIVE-MODE EFFICIENCY CSL EQUATIONS FOR PRODUCT CLASSES 

TABLE 5.34 NO-LOAD POWER CSL EQUATIONS FOR PRODUCT CLASSES A1, A2, A3, 

TABLE 5.35 THE LOW-VOLTAGE PRODUCT CLASSES’ (A2, A4) ACTIVE MODE 

TABLE 5.36 AC/AC PRODUCT CLASSES’ (A3, A4) MAXIMUM ALLOWABLE NO-LOAD 

TABLE 5.45 MULTIPLE-VOLTAGE EPS CANDIDATE STANDARD LEVELS OF
 

TABLE 5.46 HIGH-POWER EPS CANDIDATE STANDARD LEVELS OF EFFICIENCY5-72
 

TABLE 5.50 THE BC REPRESENTATIVE UNITS FOR EACH REPRESENTATIVE 

TABLE 5-51. ENERGY CONSUMPTION OF BATTERY CHARGER REPRESENTATIVE 

TABLE 5.52 WEEKLY USAGE ASSUMPTIONS FOR BATTERY CHARGER 

TABLE 5.53 AVERAGE MARKUP APPLIED TO THE BOM COSTS OBTAINED BOTH
 

THROUGH TEARDOWNS AS WELL AS MANUFACTURER INTERVIEWS TO 

MANUFACTURER DATA .......................................................................................... 5-55
 

(MANUFACTURER INTERVIEWS) .......................................................................... 5-56
 

(MANUFACTURER INTERVIEWS) .......................................................................... 5-56
 

(MANUFACTURER INTERVIEWS) .......................................................................... 5-56
 

(MANUFACTURER INTERVIEWS) .......................................................................... 5-57
 

A1, A2, A3, AND A4. ................................................................................................... 5-65
 

AND A4......................................................................................................................... 5-66
 

EFFICIENCY EQUATIONS......................................................................................... 5-67
 

POWER EQUATIONS.................................................................................................. 5-68
 

TABLE 5.37 MULTIPLE VOLTAGE EPS REPRESENTATIVE PRODUCT CLASSES..... 5-69
 

TABLE 5.38 MULTIPLE-VOLTAGE EPS REPRESENTATIVE UNITS.............................. 5-69
 

TABLE 5.39 HIGH POWER EPS REPRESENTATIVE PRODUCT CLASSES ................... 5-69
 

TABLE 5.40 HIGH-POWER EPS REPRESENTATIVE UNITS ............................................ 5-69
 

TABLE 5.41 PROPOSED MEDICAL EPS REPRESENTATIVE PRODUCT CLASSES..... 5-70
 

TABLE 5.42 POSSIBLE MEDICAL EPS REPRESENTATIVE UNITS................................ 5-70
 

TABLE 5.43 PROPOSED MADB EPS REPRESENTATIVE PRODUCT CLASSES ........... 5-70
 

TABLE 5.44 POSSIBLE MADB EPS REPRESENTATIVE UNITS ...................................... 5-71
 

EFFICIENCY ................................................................................................................ 5-71
 

TABLE 5.47 MEDICAL EPS CANDIDATE STANDARD LEVELS OF EFFICIENCY ...... 5-72
 

TABLE 5.48 MADB EPS CANDIDATE STANDARD LEVELS OF EFFICIENCY............. 5-73
 

TABLE 5.49 REPRESENTATIVE PRODUCT CLASSES ..................................................... 5-78
 

PRODUCT CLASS. ...................................................................................................... 5-80
 

UNITS AT EACH EFFICIENCY LEVEL.................................................................... 5-83
 

REPRESENTATIVE UNITS ........................................................................................ 5-84
 

OBTAIN THE MSP....................................................................................................... 5-94
 

TABLE 5.54 CHARACTERISTICS OF TYPICAL UNITS FOR PRODUCT CLASS 1 

DESCRIBED BY MANUFACTURERS DURING INTERVIEWS. ........................... 5-98
 

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TABLE 5.55 COMPARISON OF MSPS FOR PRODUCT CLASS 1’S REPRESENTATIVE 

UNIT OBTAINED FROM MANUFACTURER INTERVIEWS. NO TEARDOWNS 

WERE PERFORMED FOR THIS REPRESENTATIVE UNIT................................. 5-101
 

TABLE 5.56 DETAILED TEST RESULTS FOR THE UNITS CORRESPONDING TO THE 

CSLS FOR REPRESENTATIVE PRODUCT CLASS 2: LOW ENERGY, LOW
 

VOLTAGE................................................................................................................... 5-103
 

TABLE 5.57 CHARACTERISTICS OF TYPICAL UNITS FOR PRODUCT CLASS 2 

DESCRIBED BY MANUFACTURERS DURING INTERVIEWS. ......................... 5-103
 

TABLE 5.58 COMPARISON OF MSPS FOR PRODUCT CLASS 2’S REPRESENTATIVE 

UNIT OBTAINED FROM MANUFACTURER INTERVIEWS VERSUS THOSE 

DEVELOPED THROUGH TEARDOWNS. .............................................................. 5-112
 

TABLE 5.59 DETAILED TEST RESULTS FOR THE UNITS CORRESPONDING TO THE 

CSLS FOR REPRESENTATIVE PRODUCT CLASS 4: LOW ENERGY, HIGH
 

VOLTAGE................................................................................................................... 5-115
 

TABLE 5.60 CHARACTERISTICS OF TYPICAL UNITS FOR PRODUCT CLASS 4 

DESCRIBED BY MANUFACTURERS DURING INTERVIEWS. ......................... 5-116
 

TABLE 5.61 COMPARISON OF MSPS FOR PRODUCT CLASS 4’S REPRESENTATIVE 

UNIT OBTAINED FROM MANUFACTURER INTERVIEWS VERSUS THOSE 

DEVELOPED THROUGH TEARDOWNS. .............................................................. 5-125
 

TABLE 5.62 DETAILED TEST RESULTS FOR THE UNITS CORRESPONDING TO THE 

CSLS FOR REPRESENTATIVE PRODUCT CLASS 5: MEDIUM ENERGY, LOW
 

VOLTAGE................................................................................................................... 5-128
 

TABLE 5.63 CHARACTERISTICS OF TYPICAL UNITS FOR PRODUCT CLASS 5 

DESCRIBED BY MANUFACTURERS DURING INTERVIEWS. ......................... 5-129
 

TABLE 5.64 COMPARISON OF MSPS FOR PRODUCT CLASS 5’S REPRESENTATIVE 

UNIT OBTAINED FROM MANUFACTURER INTERVIEWS VERSUS THOSE 

DEVELOPED THROUGH TEARDOWNS. .............................................................. 5-135
 

TABLE 5.65 CHARACTERISTICS OF TYPICAL UNITS FOR PRODUCT CLASS 7 

DESCRIBED BY MANUFACTURERS DURING INTERVIEWS. ......................... 5-136
 

TABLE 5.66 COMPARISON OF MSPS FOR PRODUCT CLASS 7’S REPRESENTATIVE
 

UNIT OBTAINED FROM MANUFACTURER INTERVIEWS VERSUS THOSE 

DEVELOPED THROUGH TEARDOWNS. .............................................................. 5-139
 

TABLE 5.67 DETAILED TEST RESULTS FOR THE UNITS CORRESPONDING TO THE 

CSLS FOR PRODUCT CLASS 10: LOW-ENERGY AC OUTPUT. ........................ 5-141
 

TABLE 5.68 CHARACTERISTICS OF TYPICAL UNITS FOR PRODUCT CLASS 10 

DESCRIBED BY MANUFACTURERS DURING INTERVIEWS. ......................... 5-142
 

TABLE 5.69 COMPARISON OF MSPS FOR PRODUCT CLASS 10’S REPRESENTATIVE 

UNIT OBTAINED FROM MANUFACTURER INTERVIEWS VERSUS THOSE 

DEVELOPED THROUGH TEARDOWNS. .............................................................. 5-147
 

TABLE 5.70 BC SHIPMENTS-WEIGHTED AVERAGE USAGE PROFILES FOR 

PRODUCT CLASSES 2, 3, AND 4 ............................................................................ 5-149
 

TABLE 5.71 CHARACTERISTICS OF TYPICAL UNITS SCALED FOR PRODUCT CLASS
 

3.................................................................................................................................... 5-150
 

TABLE 5.72 RESULTING COST AND EFFICIENCY RELATIONSHIP FOR BC PRODUCT 

CLASS 3. ..................................................................................................................... 5-150
 

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TABLE 5.73 CHARACTERISTICS OF TYPICAL UNITS SCALED FOR PRODUCT CLASS
 

6.................................................................................................................................... 5-151
 

TABLE 5.74 RESULTING COST AND EFFICIENCY RELATIONSHIP FOR BC PRODUCT 

TABLE 5.75 COST AND EFFICIENCY RELATIONSHIP FOR 2.5W EPS
 

TABLE 5.76 CHARACTERISTICS OF TYPICAL UNITS SCALED FOR PRODUCT CLASS
 

TABLE 5.77 RESULTING COST AND EFFICIENCY RELATIONSHIP FOR BC PRODUCT 

TABLE 5.78 CHARACTERISTICS OF TYPICAL UNITS SCALED FOR PRODUCT CLASS
 

TABLE 5.79 RESULTING COST AND EFFICIENCY RELATIONSHIP FOR BC PRODUCT 

CLASS 6. ..................................................................................................................... 5-151
 

(MANUFACTURER INTERVIEWS) ........................................................................ 5-152
 

8.................................................................................................................................... 5-152
 

CLASS 8. ..................................................................................................................... 5-152
 

9.................................................................................................................................... 5-153
 

CLASS 9. ..................................................................................................................... 5-153
 

LIST OF FIGURES 

FIGURE 5.1. MARKET CHARACTERIZATION FOR POPULAR WALL ADAPTERS 

(BUBBLE CHART)......................................................................................................... 5-5
 

FIGURE 5.2. MARKET CHARACTERIZATION FOR POPULAR WALL ADAPTERS (BAR 

FIGURE 5.3 DISTRIBUTION OF BATTERY VOLTAGE AND ENERGY FOR HIGHFIGURE 5.4 CSL SCALED AVERAGE ACTIVE-MODE EFFICIENCY VS. OUTPUT 

CHART)........................................................................................................................... 5-6
 

VOLUME APPLICATIONS IDENTIFIED IN THE MARKET SURVEY................... 5-7
 

POWER.......................................................................................................................... 5-11
 

FIGURE 5.5 CSL NO-LOAD POWER VS. OUTPUT POWER.............................................. 5-12
 

FIGURE 5.6 SURVEY OF EPS EFFICIENCIES BY APPLICATION ................................... 5-17
 

FIGURE 5.7 NO-LOAD POWER VS. SCALED EFFICIENCY FOR 2.5-WATT UNITS..... 5-19
 

FIGURE 5.8 NO-LOAD POWER VS. SCALED EFFICIENCY FOR 18-WATT UNITS...... 5-20
 

FIGURE 5.9 NO-LOAD POWER VS. SCALED EFFICIENCY FOR 60-WATT UNITS...... 5-22
 

FIGURE 5.10 NO-LOAD POWER VS. SCALED EFFICIENCY FOR 120-WATT UNITS.. 5-23
 

FIGURE 5.11 FULL COST OF PRODUCT: BREAKDOWN OF PRODUCTION AND NONPRODUCTION COSTS ................................................................................................ 5-25
 

FIGURE 5.12 SAMPLE EFFICIENCY AND MSP MANUFACTURER DATA FOR THE 2.5W
 

FIGURE 5.13 SAMPLE NO-LOAD POWER AND MSP MANUFACTURER DATA FOR THE 

FIGURE 5.14 ILLUSTRATION OF AGGREGATION METHOD IN TWO DIMENSIONS
 

FIGURE 5.15 ILLUSTRATION OF AGGREGATION METHOD IN TWO DIMENSIONS
 

REPRESENTATIVE UNIT........................................................................................... 5-29
 

2.5W REPRESENTATIVE UNIT................................................................................. 5-30
 

FOR THE 2.5W REPRESENTATIVE UNIT ............................................................... 5-31
 

FOR THE 2.5W REPRESENTATIVE UNIT ............................................................... 5-32
 

FIGURE 5.16 SCALING STEPS TO NORMALIZE EFFICIENCIES AND COSTS............. 5-38
 

FIGURE 5.17 SCALING AN EPS EFFICIENCY DATA POINT WITH NAMEPLATE
 

OUTPUT POWER......................................................................................................... 5-39
 

FIGURE 5.18 60-WATT EPS PRODUCT FAMILIES FOR OUTPUT VOLTAGE SCALING 5­

42
 

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FIGURE 5.19 HIGH-EFFICIENCY CURVE USED FOR OUTPUT VOLTAGE SCALING 5-42
 

FIGURE 5.20 PRODUCT FAMILIES USED TO CREATE LOW-EFFICIENCY CURVE FOR
 

OUTPUT VOLTAGE SCALING.................................................................................. 5-43
 

FIGURE 5.21 LOW-EFFICIENCY CURVE USED FOR OUTPUT VOLTAGE SCALING. 5-44
 

FIGURE 5.22 HIGH-EFFICIENCY AND LOW-EFFICIENCY CURVES FOR OUTPUT 

VOLTAGE SCALING .................................................................................................. 5-44
 

FIGURE 5.23 2.5-WATT EPS PRODUCT FAMILIES FOR OUTPUT VOLTAGE SCALING5­

FIGURE 5.24 18-WATT EPS PRODUCT FAMILIES FOR OUTPUT VOLTAGE SCALING 5­

FIGURE 5.25 60-WATT EPS PRODUCT FAMILIES FOR OUTPUT VOLTAGE SCALING 5­

FIGURE 5.26 120-WATT EPS PRODUCT FAMILIES FOR OUTPUT VOLTAGE SCALING
 

45
 

46
 

46
 

........................................................................................................................................ 5-47
 

FIGURE 5.27 CORD LENGTHS OF TESTED EPS UNITS ................................................... 5-49
 

FIGURE 5.28 THE FULL MARKUP CHAIN, INCLUDING THE STEPS FROM BOM TO 

MPC TO MSP................................................................................................................ 5-52
 

FIGURE 5.29 2.5W MSP VS. EFFICIENCY CURVES FOR MANUFACTURER AND 

FIGURE 5.30 2.5W MSP VS. NO-LOAD POWER CURVES FOR MANUFACTURER AND 

FIGURE 5.31 18W MSP VS. EFFICIENCY CURVES FOR MANUFACTURER AND 

FIGURE 5.32 18W MSP VS. NO-LOAD POWER CURVES FOR MANUFACTURER AND 

FIGURE 5.33 60W MSP VS. EFFICIENCY CURVES FOR MANUFACTURER AND 

FIGURE 5.34 60W MSP VS. NO-LOAD POWER CURVES FOR MANUFACTURER AND 

FIGURE 5.35 120W MSP VS. EFFICIENCY CURVES FOR MANUFACTURER AND 

FIGURE 5.36 120W MSP VS. NO-LOAD POWER CURVES FOR MANUFACTURER AND 

TESTING AND TEARDOWN DATA ......................................................................... 5-59
 

TESTING AND TEARDOWN DATA ......................................................................... 5-59
 

TESTING AND TEARDOWN DATA ......................................................................... 5-60
 

TESTING AND TEARDOWN DATA ......................................................................... 5-60
 

TESTING AND TEARDOWN DATA ......................................................................... 5-61
 

TESTING AND TEARDOWN DATA ......................................................................... 5-62
 

TESTING AND TEARDOWN DATA ......................................................................... 5-63
 

TESTING AND TEARDOWN DATA ......................................................................... 5-63
 

FIGURE 5.37. DISTRIBUTION OF ANNUAL SHIPMENTS BY PRODUCT CLASS. ....... 5-77
 

FIGURE 5.38. DISTRIBUTION OF ANNUAL ENERGY CONSUMPTION BY PRODUCT 

CLASS. .......................................................................................................................... 5-77
 

FIGURE 5.39 THE BC REPRESENTATIVE UNITS SUPERIMPOSED OVER THE BC
 

FIGURE 5.40 REPRESENTATIVE UNITS AND UNITS DESCRIBED BY 

FIGURE 5.41 ILLUSTRATION OF THE REGRESSION ANALYSIS OF MANUFACTURER
 

FIGURE 5.42 ILLUSTRATION OF TRANSLATION OF CURVES TO OBTAIN
 

MARKET SURVEY RESULTS. .................................................................................. 5-81
 

MANUFACTURERS. ................................................................................................... 5-86
 

COST-EFFICIENCY DATA......................................................................................... 5-89
 

INCREMENTAL COSTS FROM THE BASELINE.................................................... 5-90
 

FIGURE 5.43 AGGREGATION OF TRANSLATED MANUFACTURER CURVES........... 5-90
 

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FIGURE 5.44 TRANSLATION OF CURVES TO OBTAIN ABSOLUTE COSTS FROM 

TEARDOWN BASELINE ............................................................................................ 5-91
 

FIGURE 5.45 THE FOUR WAYS THAT BC AND END-USE PRODUCT MANUFACTURE 

CAN BE DIVIDED BETWEEN THE BC SUPPLIER OR ORIGINAL DEVICE 

MANUFACTURER (ODM) AND THE ORIGINAL EQUIPMENT MANUFACTURER
 

(OEM)............................................................................................................................ 5-93
 

FIGURE 5.46 24-HOUR EFFICICIENCY STANDARD PROPOSED BY PG&E, WHICH 

COULD BE USED TO SCALE THE ANALYSIS OF THE REPRESENTATIVE UNIT 

TO BCS WITH DIFFERING BATTERY ENERGIES................................................. 5-96
 

FIGURE 5.47 TEST RESULTS FOR REPRESENTATIVE PRODUCT CLASS 1: LOW
 

ENERGY, INDUCTIVE................................................................................................ 5-97
 

FIGURE 5.48 ILLUSTRATION OF THE MSP FOR THIS REPRESENTATIVE UNIT AT
 

EACH CSL. ................................................................................................................. 5-100
 

FIGURE 5.49 TEST RESULTS FOR REPRESENTATIVE PRODUCT CLASS 2: LOW
 

ENERGY, LOW VOLTAGE. ..................................................................................... 5-102
 

FIGURE 5.50 INPUT POWER WAVEFORM DURING CHARGE AND MAINTENANCE 

MODES FOR THE BASELINE UNIT. THE FULL 24-HOUR PLOT (A) SHOWS
 

SOME INCREASED ACTIVITY IN MAINTENANCE, POSSIBLY ASSOCIATED
 

WITH PHONE OPERATION, WHILE THE SIX-HOUR FRAGMENT (B) SHOWS
 

THE EXPONENTIAL CHARACTERISTIC TYPICAL OF SLOW CHARGERS. .. 5-106
 

FIGURE 5.51. THE TOP AND BOTTOM OF THE SLIGHTLY LESS-EFFICIENT BEST-INMARKET CAMERA CHARGER. NOTE THE LACK OF ANY INTEGRATED 

CIRCUIT CONTROLLER. ......................................................................................... 5-108
 

FIGURE 5.52 PCBS OF DIGITAL CAMERA CHARGERS MEETING CSL 1. NOTE THE
 

HIGHLIGHTED MICROCONTROLLER IN A BLACK 14-PIN SURFACE-MOUNT 

PACKAGE IN THE LEFT PHOTOGRAPH. SIMILAR FUNCTIONALITY IS
 

PROVIDED IN THE OTHER CHARGER BY THE DEDICATED CHARGER IC
 

HIGHLIGHTED AT THE RIGHT.............................................................................. 5-109
 

FIGURE 5.53FRAGMENT OF THE INPUT POWER WAVEFORM DURING CHARGE AND
 

MAINTENANCE MODES FOR THE LESS EFFICIENT CSL2 DIGITAL CAMERA 

CHARGER. ................................................................................................................. 5-110
 

FIGURE 5.54 FRAGMENT OF THE INPUT POWER WAVEFORM DURING CHARGE 

AND MAINTENANCE MODES FOR THE MORE EFFICIENT CSL2 DIGITAL
 

CAMERA CHARGER. ............................................................................................... 5-111
 

FIGURE 5.55 MSPS FOR EACH CSL FOR REPRESENTATIVE UNIT 2. ........................ 5-112
 

FIGURE 5.56 RESULTS OF UNIVERSAL BATTERY CHARGER TEST RESULTS
 

PERFORMED BY ECOS CONSULTING WITH BATTERIES OF VARYING
 

ENERGIES. ALL TEST RESULTS FOR A GIVEN CHARGER ARE PERFORMED 

WITH BATTERIES WITH THE SAME VOLTAGE. ............................................... 5-113
 

FIGURE 5.57 ILLUSTRATION OF THE LIMITED OVERLAP IN BC CHARACTERISTICS
 

BETWEEN NOTEBOOK COMPUTERS AND MOTOR-OPERATED APPLIANCES 

IN THE LOW-ENERGY HIGH-VOLTAGE PRODUCT CLASS (BASED ON
 

ADVERTISED BATTERY VOLTAGE AND ENERGY)......................................... 5-114
 

FIGURE 5.58 TEST RESULTS FOR REPRESENTATIVE PRODUCT CLASS 4: LOW
 

ENERGY, HIGH VOLTAGE ..................................................................................... 5-115
 

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FIGURE 5.59 PHOTOGRAPHS OF THE TOP AND BOTTOM OF THE MOTHERBOARD 

OF THE NOTEBOOK COMPUTER, WITH POWER MANAGEMENT AND 

BATTERY CHARGING COMPONENTS HIGHLIGHTED..................................... 5-116
 

FIGURE 5.60 THE INPUT POWER OF THE BASELINE UNIT DURING CHARGING AND 

MAINTENANCE MODES. ........................................................................................ 5-119
 

FIGURE 5.61FRAGMENT OF THE INPUT POWER WAVEFORM DURING CHARGE AND
 

FIGURE 5.62 THE EFFICIENCY RELATED MANUFACTURING COST OF THE FOUR
 

MAINTENANCE MODES FOR THE CSL 1 UNIT.................................................. 5-120
 

COMMERCIALLY ANALYZED BCS IN THIS PRODUCT CLASS. .................... 5-125
 

FIGURE 5.63 TEST RESULTS FOR REPRESENTATIVE PRODUCT CLASS 5: MEDIUM 

ENERGY, LOW VOLTAGE. ..................................................................................... 5-127
 

FIGURE 5.64 PHOTOGRAPHS OF THE BASELINE MARINE CHARGER, SHOWING (A)
 

THE LINE-FREQUENCY TRANSFORMER AND (B) HEATSINK-MOUNTED SCR. 

NOTE THE DIFFERENCE IN SIZE AND DESIGN COMPARED TO THE LOWENERGY BCS............................................................................................................. 5-130
 

FIGURE 5.65 FRAGMENT OF THE INPUT POWER WAVEFORM DURING CHARGE 

AND MAINTENANCE MODES FOR THE BASELINE UNIT. .............................. 5-131
 

FIGURE 5.66 PHOTOGRAPHS OF THE IMPROVED MARINE CHARGER, SHOWING (A) 

THE LINE-FREQUENCY TRANSFORMER AND (B) COMPLEX CHARGECONTROL PCB. ......................................................................................................... 5-132
 

FIGURE 5.67FRAGMENT OF THE INPUT POWER WAVEFORM DURING CHARGE AND
 

MAINTENANCE MODES FOR THE CSL 1 UNIT.................................................. 5-133
 

FIGURE 5.68 COST-EFFICIENCY RESULTS AT EACH CSL FOR REPRESENTATIVE 

FIGURE 5.69 MANUFACTURER COST EFFICIENCY RELATIONSHIP FOR 

FIGURE 5.70 TEST RESULTS FOR THE LOW-ENERGY, AC-OUTPUT 

FIGURE 5.71 INPUT POWER WAVEFORM DURING CHARGE AND MAINTENANCE 

FIGURE 5.72 PHOTOGRAPH OF THE PCB OF THE BASELINE UNIT FOR THIS
 

FIGURE 5.73 INPUT POWER WAVEFORM DURING CHARGE AND MAINTENANCE 

FIGURE 5.74 TEARDOWN AND INTERVIEW MSPS AT EACH CSL FOR 

UNIT 5......................................................................................................................... 5-135
 

REPRESENTATIVE UNIT 7...................................................................................... 5-138
 

REPRESENTATIVE PRODUCT CLASS.................................................................. 5-140
 

MODES FOR THE CSL 1 UNIT. ............................................................................... 5-143
 

PRODUCT CLASS. THE BC CIRCUITRY IS MAINLY TO THE LEFT................ 5-144
 

MODES FOR THE CSL 1 UNIT. ............................................................................... 5-145
 

REPRESENTATIVE UNIT 10.................................................................................... 5-147
 

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CHAPTER 5. ENGINEERING ANALYSIS
 

5.1 INTRODUCTION 

The U.S. Department of Energy (DOE) performed an engineering analysis to establish 

the relationship between the manufacturer selling price (MSP) and the energy efficiency of 

battery chargers (BCs) and external power supplies (EPSs). The relationship between the MSP 

and energy efficiency, or the cost-efficiency relationship, serves as the basis for cost-benefit 

calculations in terms of individual customers, manufacturers, and the Nation. This section 

provides an overview of the engineering analysis, discusses the representative product classes, 

establishes baseline unit specifications for those product classes, discusses incremental efficiency 

levels, discusses the analysis and results for the representative product classes, and establishes a 

scaling methodology to those product classes not analyzed directly. 

The primary inputs of the engineering analysis are cost and efficiency data derived from 

1) test data and teardown analysis, and 2) manufacturer interviews. Additional inputs include 

design options from the screening analysis (preliminary technical support document (TSD) 

chapter 4). The primary output of the engineering analysis is a set of cost-efficiency curves. In a 

subsequent life-cycle cost analysis (preliminary TSD chapter 8), DOE used the cost-efficiency 

curves to determine customer prices for each of the products analyzed in the engineering analysis 

by applying the appropriate distribution channel markups. 

5.2 ENGINEERING ANALYSIS METHODOLOGY 

DOE structured its engineering analysis using two methodologies: (1) the testing and teardown 

approach, which involves testing commercially available products and tearing down the products 

to determine ―bottom-up‖ manufacturing costs based on a detailed bill of materials and (2) the 

efficiency-level approach, which involves interviewing manufacturers to determine the relative 

costs of achieving increases in efficiency, without regard to the particular design options used to 

achieve such increases. The following summarizes the general steps taken throughout the 

engineering analysis: 

Market Survey: DOE surveyed applications that use BCs and EPSs to determine the most 

popular units in the market. DOE focused its analysis on these popular units. 

Representative Product Classes and Representative Units: DOE reviewed covered BCs and 

EPSs and their associated product classes. DOE selected certain classes and units as 

―representative‖ and concentrated its analytical effort on these because they represent a 

significant majority of units and because analysis on these units and classes can be extended to 

all units and classes. For those product classes that are not analyzed directly, DOE extrapolates 

the analysis from representative product classes. 

Baseline Efficiency Level: For all representative units, DOE establishes baseline efficiency 

levels, which serve as reference points against which DOE measures changes resulting from 

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potential amended energy conservation standards. To determine energy savings and changes in 

price, DOE compares each higher energy-efficiency level with the baseline efficiency level. For 

EPSs the baseline efficiency level is determined by Federal energy conservation standards set by 

EISA 2007. Because of the wide variety of designs that manufacturers use to meet EISA 2007 

standards, DOE does not describe specific baseline units with particular designs. There are no 

existing federal standards for BCs, so the baseline BC reflects the lowest-efficiency units in the 

market. 

Unit Testing: DOE purchased and measured the efficiency of BC and EPS units to characterize 

the full range of efficiencies in the market and the ranges of efficiencies of the representative 

units. 

Candidate Standard Levels. After identifying baseline efficiency levels, DOE developed 

candidate standard levels based on: (1) voluntary efficiency specifications, (2) commercially 

available high-efficiency units determined by testing units, (3) intermediate points in the market 

and (4) the maximum technologically feasible (max-tech) efficiency level determined by 

interviewing manufacturers of BCEPS, integrated-circuit controllers for BCEPS, and 

applications that use BCEPS. The max-tech level was independently verified by subject matter 

experts. 

Unit Teardowns: DOE selected certain test units to characterize the costs for the representative 

units to meet the CSLs. To determine costs, DOE subcontracted iSuppli Corporation, an industry 

expert in costs of consumer electronics, to perform teardowns. 

Manufacturer Interviews: DOE’s contractors interviewed manufacturers of BCEPS, 

manufacturers of integrated circuit (IC) controllers for BCEPS, and manufacturers of products 

with applications that use BCEPS. During these interviews DOE obtained confidential design 

cost and efficiency information which DOE aggregated to derive manufacturer-based 

relationships between cost and efficiency for BCEPS. 

Price Analysis. The costs output from the engineering analysis is at the point in the product value 

chain where the BCEPS manufacturer sells its product to the application manufacturer, termed 

the manufacturer selling price (MSP). However, in some cases DOE obtained costs for BCs and 

EPSs earlier in the production process such as the (1) bill of materials (BOM), which describes 

the product’s components in detail, including all manufacturing steps required to make and/or 

assemble each part, or the (2) manufacturer production costs (MPCs), which is the cost of the BC 

or EPS after it leaves the factory. By applying manufacturer markups to the BOMs and MPCs, 

DOE calculated the MSPs used in the final cost-efficiency curves. 

The sections that follow discuss how DOE applied this methodology to create the engineering 

analysis. 

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5.3 MARKET SURVEY TO SELECT REPRESENATIVE UNITS
 

DOE began the development of the preliminary analysis with a market survey in the 

summer of 2009 as the basis for selecting representative units for both BCs and Class A EPSs. 

At the time of the survey non-Class A EPSs were part of a separate determination analysis and 

therefore were addressed separately in that rulemaking. The goal of the survey for BCs and 

Class A EPSs was to determine market segments from which to select the representative units. 

To best capture the BC and Class A EPS markets, DOE focused on the most popular applications 

that use BCs and Class A EPSs. The survey consisted of the following steps: 

1. Identify the types of applications that use BCs and Class A EPSs 

2. Estimate the annual shipments and the energy consumption for those applications 

3. Select applications to focus on based on significant shipments and/or energy consumption 

4. Visit websites and retail outlets to survey product characteristics of popular models 

5. Combine the results into BC and Class A EPS market profiles 

6. Select representative units based on the market profiles 

As discussed in Chapter 3 of this preliminary TSD, to date DOE identified 83 applications 

that use BCs and/or EPSs. When DOE conducted a market survey in the summer of 2009 it had 

identified 51 applications. Of those applications, DOE had obtained estimated annual shipments 

for 43. Among those applications, DOE prioritized EPS-focused research on 13 application 

types that were expected to have large shipments and/or energy consumption. 

1. Computer Speakers 

2. Cordless Phones/Answering Devices 

3. Digital Photo Frames 

4. E-Books 

5. External Hard Drives 

6. Inkjet MFDs and Printers 

7. LAN Equipment 

8. Mobile Phones 

9. MP3 Speaker Docks 

10. Notebook Computers 

11. Portable DVD Players 

12. USB Wall Adapters 

13. VoIP Adapters 

DOE conducted similar model counts to assess models that would most impact the BC 

analysis. 

1. Camcorders 

2. Cordless Phones/Answering Devices 

3. Digital Cameras 

4. E-Books 

5. Electric Bicycles 

6. Golf Carts 

7. Handheld Vacuum Cleaners 

8. Handheld Video Games 

9. Hedge and Lawn Tools 

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10. Marine Chargers 

11. Mobile Phones 

12. Notebook Computers 

13. Power Tools 

14. Robotic Vacuum Cleaners 

15. Uninterruptible Power Supplies 

16. Universal Battery Chargers 

For the selected applications, DOE identified the most popular product models, 

considered to be those on the best-seller lists of several popular online retailers (e.g., 

Amazon.com, BestBuy.com, etc.). In total, DOE identified 366 application models among the 

13 EPS-focused application types. For each model, DOE noted whether the model included a 

wall adapter, a battery, both, or neither. Among the 366 models, 281 were identified as having 

wall adapters, and DOE was able to discern the expected nameplate output power for 230 of the 

models – from 1.2 watts for a cordless phone to 120 watts for a notebook computer. In cases 

where the BC or EPS information was not readily available, DOE consulted publicly available 

manufacturer information and noted the characteristics of the product. 

Subsequently, for EPSs, DOE combined the information it gathered on application 

shipments, model count, and model power rating to characterize popular wall adapters by 

nameplate output power, which DOE used as an approximation of the EPS market. Figure 5.1 

and Figure 5.2 show the results of the market characterization in two formats: bubble chart and 

bar chart, respectively. The size of the ―bubbles‖ in Figure 5.1 gives a relative measure of how 

many models DOE counted for each application at each nameplate output power rating. The 

height of a bubble corresponds to the total shipments of the application. For example, mobile 

phones have the highest shipments at approximately 143M per year. 

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100,000

1,000,000

10,000,000

100,000,000

1,000,000,000

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 Annual Shipments

Nameplate Output Power [W]

Computer speakers Cordless Phones/Answering Devices Digital Photo Frames

E-Books External hard drives Inkjet MFDs and printers

LAN Equipment Mobile phones MP3 Speaker Docks

Notebook computers Portable DVD players VoIP Adapters

Figure 5.1. Market Characterization for Popular Wall Adapters (bubble chart) 

In Figure 5.2 application shipments have been apportioned relative to model count; the 

height of each bar indicates the cumulative EPS shipments at a particular nameplate output 

power. For example, the 143M shipments for mobile phones are divided between wall adapters 

with nameplate output power ratings of approximately 3 watts and 5 watts, 16M and 127M 

respectively. The bar on the x-axis corresponding to 3-watt EPSs consists of the 16M mobile 

phone EPSs and 7M cordless phone EPSs. Thus the total estimated shipments for 3-watt EPSs 

are 23M units per year. These volumes were a major factor in the process of selecting the 

representative units, which is detailed in 5.4.1. 

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0

15,000,000

30,000,000

45,000,000

60,000,000

75,000,000

90,000,000

105,000,000

120,000,000

135,000,000

150,000,000

0 0 1 1 1 2 3 4 5 6 7 8 9 1 0 1 2 1 4 1 6 1 8 2 0 2 2 2 4 2 6 2 8 3 0 3 2 3 4 3 6 3 8 4 0 4 2 4 4 4 6 4 8 5 0 5 2 5 4 5 6 5 8 6 0 6 2 6 4 6 6 6 8 7 0 Annual Shipments

Nameplate Output Power [W]

VoIP Adapters

Portable DVD players

Notebook computers

MP3 Speaker Docks

Mobile phones

LAN Equipment

Inkjet MFDs and printers

External hard drives

E-Books

Digital Photo Frames

Cordless Phones/Answering Devices

Computer speakers

Figure 5.2. Market Characterization for Popular Wall Adapters (bar chart) 

While the EPS products were grouped by nameplate output power, the BC product 

classes—described in chapter 3—are defined by battery voltage (in volts) and energy (in watthours). Therefore, DOE grouped the models evaluated during the market survey by battery 

voltage and energy. A comparison of the resultant market distribution to the BC product classes 

can be seen in Figure 5.3. This market distribution was subsequently used to select the BC 

representative product classes and units, as detailed in sections 5.6.1 and 5.6.2, respectively. 

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Figure 5.3 Distribution of battery voltage and energy for high-volume applications identified in the market survey 

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5.4 CLASS A EXTERNAL POWER SUPPLY ENGINEERING ANALYSIS 

In this section, DOE presents a full engineering analysis including cost-efficiency curves 

for Class A EPSs. In section 5.5, DOE presents a preliminary discussion of the engineering 

analysis for non-Class A EPSs that includes a description of representative products classes, 

representative units, and candidate standard levels of efficiency. For non-Class A EPSs, a more 

detailed engineering analysis including product testing and teardown results, and manufacturerderived cost-efficiency curves will be derived for the NOPR analysis. 

5.4.1 Class A EPS Representative Product Classes and Representative Units 

DOE elected to focus the engineering analysis on the AC-DC basic-voltage output 

product class A1 as the representative product class among the four product classes shown in 

Table 5.1 because the majority of units in the market are in that product class. The other three 

product classes were not explicitly analyzed in an engineering analysis using physical test units 

or manufacturer data; rather, the analysis for product class A1 was extended to the other three 

product classes using scaling relationships (discussed further in section 5.4.6 and section 5.4.10). 

Product class A1 includes EPSs for low-power products such as cordless phones and cellular 

phones, mid-power products such as modems and routers, and higher-power products such as 

notebook computers. 

Table 5.1 Proposed EPS Representative Product Class and Scaled Product Classes 

Basic Voltage Output Low Voltage Output * 

AC-DC Conversion A1, Representative Product Class A2, Scaled 

AC-AC Conversion A3, Scaled A4, Scaled 

* Low voltage output EPSs have nameplate output voltage less than six volts and nameplate output current greater 

than or equal to 550 milliamps. All other EPSs are basic voltage output. 

Within the representative product class, DOE chose representative units based on the 

following criteria: 

• Select units only within the representative product class A1 

• Select a sufficient amount of nameplate output power points to curve fit the CSLs 

• Focus on popular areas in the market 

• Ensure that there are many units to test 

DOE chose to have multiple representative units for the EPS engineering analysis since 

EPS product classes span a wide range of output power, and efficiency is strongly affected by 

output power. Since DOE elected to express the CSLs as continuous functions of nameplate 

output power it was necessary to select several representative units to characterize each CSL. To 

accomplish that goal, DOE chose to characterize four nameplate output power regions: low 

power (1.2 watts to 10 watts), mid power (15 watts to 30 watts), high power (30 watts to 90 

watts), and maximum power of 120 watts. The representative units are focused on lower powers 

because there lies the greatest diversity of EPS efficiency. Above 50 watts, there is much less 

variation in EPS efficiency, hence there is less need for characterization. 

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After selecting the number of representative units, DOE selected each unit’s nameplate 

output power and nameplate output voltage – the two characteristics that most influence EPS 

efficiency. The combination of power and voltage for each representative unit needed to result 

in the EPS being in the representative product class A1, per DOE’s decision to analyze only that 

product class. Further, by ensuring that all units were from the same product class, DOE could 

scale results across all nameplate output powers within the representative product class during 

the later stages of the analysis. 

When defining the representative unit values, DOE considered specifying the same 

output voltage for all representative units, but instead specified different output voltages for each 

representative unit. DOE took this approach because there is a trend in the market for EPSs with 

higher nameplate output power to have higher nameplate output power. For instance, low-power 

cell phone chargers tend to have nameplate output voltage at 5 volts whereas higher-power 

notebook computers tend to have nameplate output voltage at 19 volts. Thus, there is not a single 

output voltage for all representative units that would accurately reflect the market. Further, 

because the representative units have the different wattages and voltages, DOE ensured that the 

CSLs are consistent with the market, since the representative units characterize the CSLs. 

DOE’s next step in selecting representative units was to focus on popular units in the 

market, which was straightforward for most representative units, except the low-power 

representative unit. Figure 5.2 shows a peak at 5 watts in the EPS market. Although DOE 

considered a 5-watt representative unit because of its prevalence, DOE instead selected a 2.5­

watt representative unit because it belonged to the representative product class A1 whereas the 5­

watt EPS was in product class A2 (shown in Table 5.2). Specifically, EPSs with both nameplate 

output voltage less than 6 volts and nameplate output current greater than or equal to 0.55 

amperes are considered to be low-voltage EPSs that are in product class A2 (if they output DC 

power) or product class A4 (if they output AC power). All of the 5-watt EPSs had nameplate 

output voltage of 5 volts, nameplate output current of 1 ampere, and DC output power. Thus all 

5-watt EPSs were in product class A2 and not viable for selection as representative units in the 

representative product class A1. In contrast, 2.5-watt EPSs had nameplate output voltage of 5­

watts and nameplate output current of 0.5 amperes. Thus the 2.5-watt EPSs are in product class 

A1 and eligible as representative units. As noted in the executive summary, DOE is seeking 

stakeholder comment on this approach in general and on whether to perform a detailed analysis 

for 5-watt, 5-volt EPSs in particular. 

Table 5.2 Evaluation of Potential Low-Power EPSs as Representative Units 

Power 

[W] 

Voltage 

[V] 

Current 

[A] 

Product 

Class 

Low-voltage criteria - < 6 V ≥ 0.55 A A2 and A4 

Valid representative unit 2.5 W 5 V 0.50 A A1 

Invalid representative unit 5 W 5 V 1.00 A A2 

The last criterion that DOE considered in selecting EPS representative units was unit 

availability. This requirement was not trivial because, although there are many applications sold 

with EPSs, a significant amount of those applications do not publish the nameplate output power 

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and voltage of their associated EPSs. Therefore, DOE targeted its analysis on EPSs that were 

clearly available for purchase at specific output powers. Based on all of the criteria presented, 

DOE selected four representative units for EPSs, listed in Table 5.3. 

Table 5.3 External Power Supply Representative Units 

Representative 

Unit 

Nameplate Output 

Power 

[watts] 

Nameplate Output 

Voltage 

[volts] 

Example 

Application 

Output 

Cord 

Length* 

[m] 

1 2.5 5 Mobile phone 1.66 

2 18 12 Modem 1.66 

3 60 15 Laptop Computer 1.66 

4 120 19 Laptop Computer 1.66 

*The standard cord length assumed for all representative units was 1.66m. Cord length did not influence the 

selection of units; it was only used to scale efficiency (see Section 5.4.6.3 for details) and cost (see Section 5.4.6.5 

for details) data. 

See Section 5.4.3 for a detailed discussion of all the EPSs tested, including those at the 

representative units. 

5.4.2 Candidate Standard Levels for Representative Product Class A1 

DOE determined the CSLs for the AC-DC basic-voltage representative product class A1 

based on existing standard levels, products available in the market, and information from 

manufacturers, in the manner shown in Table 5.4. 

Table 5.4 Candidate Standard Levels of Efficiency for Product Class A1 

Number Reference Basis 

CSL0 EISA 2007 EISA 2007 equations for efficiency and no-load power 

CSL1 Energy Star 2.0 Energy Star 2.0 equations for efficiency and no-load power 

CSL2 Intermediate Curve fit to manufacture data points 

CSL3 Best in Market Curve fit to test unit data points 

CSL4 Max Tech Curve fit to manufacture data points 

The CSL equations, as well as the representative unit test and manufacturer data are 

illustrated in Figure 5.4 for efficiency, and in Figure 5.5 for no-load power. A discussion of the 

exact equations and reasoning underlying each of the four CSLs illustrated in Figure 5.4 and 

Figure 5.5, follows, starting with CSL0. 

Figure 5.4 shows CSL equations that are higher in efficiency with higher CSLs, for a 

given nameplate output power. This represents increasingly stringent standards with higher 

CSLs. For each of the representative units and CSLs there is a corresponding aggregated 

manufacturer data point and testing and teardown data point, except for CSL4, which has no test 

data because it is the max-tech level, and CSL2, which has no test data because it was chosen to 

be an intermediate level between the Energy Star 2.0 and the best-in-market levels. As shown in 

Figure 5.4, the CSLs are fit closely to the data (see Section 5.4.10 for details on curve-fitting), 

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with the added constraint that they never go above a manufacturer or test data point in efficiency, 

for a given nameplate output power. 

#876

#935

#996

#949

#118

#941

#999

#834

#838

#854

#951

55%

60%

65%

70%

75%

80%

85%

90%

95%

0 2 0 4 0 6 0 8 0 100 120

Scaled Average Active-Mode Efficiency [%] 

Output Power [W]

Scaled Average Active-Mode

Efficiency vs. Output Power

Test Data

Manufacturer Data

EISA

CSL1

CSL2

CSL3

CSL4

Figure 5.4 CSL Scaled Average Active-Mode Efficiency vs. Output Power 

Figure 5.5 shows CSL equations that are lower or equal in no-load power with higher 

CSLs, for a given nameplate output power. This represents increasingly stringent standards with 

higher CSLs. For each of the representative units and CSLs there is a corresponding aggregated 

manufacturer data point and testing and teardown data point, except for CSL4, which has no test 

data because it is the max-tech level, and CSL2, which has no test data because it was chosen to 

be an intermediate level between the Energy Star 2.0 and the best-in-market levels. As shown in 

Figure 5.4, the CSLs are fit closely to the data (see Section 5.4.10 for details on curve-fitting), 

with the added constraint that they never go below a manufacturer or test data point in no-load 

power, for a given nameplate output power. 

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#876

#935

996

#949

#118

#941

#999

#834

#838

#854

#951

0

0.1

0.2

0.3

0.4

0.5

0 2 0 4 0 6 0 8 0 100 120 N o-Load Power [W]

Output Power [W]

No-Load Power vs. Output Power

Test Data

Manufacturer Data

CSL0

CSL1

CSL2

CSL3

CSL4

Figure 5.5 CSL No-Load Power vs. Output Power 

Currently, EPCA, as amended by EISA 2007, determines EPS minimum efficiency and 

maximum no-load power consumption as a function of nameplate output power (Pout), shown in 

Table 5.5 and Table 5.6 , respectively. For this analysis, the baseline efficiency level, CSL0, for 

each representative unit is the EISA level at the corresponding nameplate output power. 

Table 5.5 Baseline (CSL0) EISA 2007 Active Mode Efficiency for Product Class A1 

Nameplate Output Power Active Mode Required Efficiency 

(decimal equivalent of a percentage) 

<1 Watt 0.5 * Pout 

1 to not more than 51 Watts 0.09 * ln (Pout) + 0.5 

>51 Watts 0.85 

Table 5.6 Baseline (CSL0) EISA 2007 No-Load Power Consumption for Product Class A1 

Nameplate Output Power Maximum Power Consumption 

Not more than 250 Watts 0.5 

Energy Star 2.0 is another level in the market, although it is a voluntary specification 

rather than a mandatory standard. Similar to EISA, the Energy Star 2.0 level is a function of 

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nameplate output power, shown in Table 5.7 and Table 5.8. As explained in chapter 3, Energy 

Star 2.0 has four product classes distinguished by the type of output power (AC/DC or AC/AC) 

and the output voltage (basic or low). DOE developed its product class structure in the same 

manner as Energy Star, hence DOE chose CSL1 to be the same as the Energy Star 2.0 level for 

AC-DC basic output voltage EPSs, at the corresponding nameplate output power. 

Table 5.7 CSL1 Energy Star 2.0 Active Mode Efficiency for Product Class A1 

Nameplate Output Power Minimum Average Efficiency in Active Mode 

(expressed as a decimal) 

0 to ≤ 1 watt 0.480 * Pout + 0.140 

> 1 to ≤ 49 watts 0.0626 * ln (Pout) + 0.622 

> 49 watts 0.870 

Table 5.8 CSL1 Energy Star 2.0 No-Load Mode Power Consumption for Product Class A1 

Nameplate Output Power Maximum Power in No-Load 

0 to ≤ 50watt 0.3 

> 50 watts 0.5 

DOE created CSL 2 to be an intermediate level between the Energy Star (CSL 1) and best 

in market (CSL 3) levels (CSL3 is explained subsequently). The specific combination of no-load 

power consumption and average efficiency for CSL 2 was chosen so as to optimize the tradeoff 

between cost and efficiency between CSL 1 and CSL 3. To do this, DOE evaluated each 

representative unit individually. DOE developed sets of efficiency and no-load power pairings 

between CSL 1 and CSL 3 and estimated their resultant unit energy consumptions (UECsa

) (see 

chapter 7 for details on calculating UECs). DOE then compared the UECs against their 

associated MSPs, which were calculated from the aggregation of manufacturer MSP data (see 

chapter 5 for details on MSP aggregation). Subsequently, the final efficiency and no-load pairing 

used to characterize CSL 2 was selected by examining which of the prospective pairings had the 

highest weighted-average savings in the LCC analysis. 

DOE then used the CSL 2 pairings for the four representative units to create equations for 

average efficiency and no-load power by curve-fitting the efficiency characteristics for CSL 2 

(see chapter 5 for details on curve fits). For both the average efficiency and no-load power CSL 

equations, DOE used equations similar to those for CSL 1, involving linear and logarithmic 

terms in the nameplate output power. DOE chose the divisions at 1 watt, 49 watts, and 50 watts 

in the CSL 2 equations so that they were consistent with the nameplate output power divisions 

between the equations for CSL 1. The CSL2 active-mode efficiency and no-load power 

equations are shown in Table 5.9 and Table 5.10, respectively. 

a UEC is also referred to as Annual Energy Consumption (AEC). 

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Table 5.9 CSL 2 Intermediate Active-Mode Efficiency for Product Class A1 

Nameplate Output Power Minimum Average Efficiency in Active Mode 

(expressed as a decimal) 

0 to ≤ 1 watt 0.49 * Pout + 0.15 

> 1 to ≤ 49 watts 0.0701 * ln(Pout) - 0.0011 * Pout +0.647 

> 49 watts 0.870 

Table 5.10 CSL 2 Intermediate No-Load Mode Power Consumption for Product Class A1 

Nameplate Output Power Maximum Power in No-Load 

0 to ≤ 50watt ≤ 0.200 watts 

> 50 watts ≤ 0.230 watts 

CSL 3 reflects the most efficient products available for sale in the market (―best in 

market‖ or BIM). As explained in section 5.4.3, DOE purchased EPSs using three sources in 

order to identify the most efficient unit in the market. First, DOE evaluated the most efficient 

units of the popular products tested in the market survey in section 5.3. Second, DOE purchased 

EPS units identified in the Energy Star 2.0 databaseb

. Third, DOE purchased units available 

through EPS distributor websites. From among these three sources, DOE considered the best in 

market EPS to be the most efficient EPSs that DOE tested, in terms of a combination of highest 

average efficiency and lowest no-load power. For those units, DOE created the equation for 

average efficiency using a curve-fit of the test results data, shown in Figure 5.4. DOE’s 

methodology for curve fitting is detailed in section 5.4.10. DOE created the equations for noload power based on the maximum no-load power among the two lower power representative 

units (2.5W and 18W) and the two higher power representative units (60W and 120W), 

respectively (see Section 5.4.10 for details). DOE followed this approach because there was no 

clear relationship between nameplate output power and no-load power consumption. DOE chose 

the divisions in the CSL 3 equations so that they were consistent with the divisions between the 

equations for CSL1. Figure 5.5 illustrates the CSL3 no-load power equations, as well as the 

CSL3 representative unit test and manufacturer data. The CSL3 active-mode efficiency and noload power equations are shown in Table 5.11 and Table 5.12, respectively. 

Table 5.11 CSL3 Best in Market Active Mode Efficiency for Product Class A1 

Nameplate Output Power Minimum Average Efficiency in Active Mode 

(expressed as a decimal) 

0 to ≤ 1 watt 0.5 * Pout + 0.16 

> 1 to ≤ 49 watts 0.071 * ln(Pout) - 0.0014 * Pout +0.67 

> 49 watts 0.8818 

b Taken from the Energy Star 2.0 external power supply results database in Sept 2009 

http://www.energystar.gov/index.cfm?fuseaction=find_a_product.showProductGroup&pgw_code=ACD. 

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Table 5.12 CSL3 Best in Market No-Load Mode Power Consumption for Product Class A1 

Nameplate Output Power Maximum Power in No-Load 

0 to ≤ 50watt 0.10 

> 50 watts 0.21 

Unlike the previous CSLs, CSL4 was not based on an evaluation of the efficiency of EPS 

units in the market, since EPSs with maximum technologically feasible efficiency are not 

commercially available due to their high cost. Rather, to estimate the efficiency of a max-tech 

unit, Navigant Consulting asked manufacturers to detail the steps they would take to achieve a 

maximum efficiency for the four representative units. The interviews included manufacturers of 

EPSs as well as manufacturers of integrated-circuit controllers for EPSs and manufacturer of 

applications that use EPSs since those manufacturers are also intimately familiar with EPS 

technologies. Navigant Consulting presented DOE with the manufacturers’ aggregated 

responses for the representative units. The aggregated responses from manufacturers are 

presented in section 5.4.5. 

In contrast to other rulemakings that use a design-options approach to develop a max-tech 

level, this rulemaking did not use a design option approach because of the significant variation in 

the prices of individual components and their effects on efficiency. The topology and parts used 

in an EPS design are typically inter-related. Hence, it is seldom possible to determine the effects 

on price and efficiency of one component in isolation. 

DOE verified the reasonableness of the aggregated manufacturer max-tech data before 

creating curve fit equations for CSL4 To that end, DOE’s subject matter experts (SMEs) 

reviewed the data and confirmed it as reasonable, except for the max-tech value for the 2.5W 

EPSs. The SMEs believe that 2.5W EPSs may be able to achieve a max tech efficiency of 80% 

rather than the 74.0% efficiency derived from manufacturers. As noted in the executive 

summary, DOE is seeking stakeholder comment on the 2.5W max tech efficiency value used. 

Nonetheless, DOE created the equations for CSL4 using the aggregate manufacturer 

value rather than the SMEs’ value because DOE had an associated cost for the aggregate 

manufacturer value. As noted in the executive summary, DOE is seeking stakeholder comment 

on the cost of an 80%-efficient EPS so that it can use that as the max-tech efficiency level for 

2.5W EPSs in the NOPR. 

Based on the representative units’ max-tech data, DOE created equations across all 

output powers, shown in Table 5.13 and Table 5.14. DOE’s methodology for curve fitting is 

detailed in section 5.4.10. DOE created the equations for no-load power based on the maximum 

no-load power among the two lower power representative units (2.5W and 18W) and the two 

higher power representative units (60W and 120W), respectively (see Section 5.4.10 for details). 

DOE chose the divisions in the CSL 4 equations so that they are consistent with the divisions 

between the equations for CSL1. Figure 5.4 and Figure 5.5 illustrate the CSL4 efficiency and 

no-load power equations in Table 5.13 and Table 5.14, respectively, as well as the aggregate 

manufacturer data for max tech. 

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Table 5.13 CSL4 Max Tech Active Mode Efficiency for Product Class A1 

Nameplate Output Power Minimum Average Efficiency in Active Mode 

(expressed as a decimal) 

0 to ≤ 1 watt 0.52* Pout + 0.17 

> 1 to ≤ 49 watts 0.079 * ln(Pout) - 0.0014 * Pout +0.67 

> 49 watts 0.9104 

Table 5.14 CSL4 Max Tech No-Load Mode Power Consumption for Product Class A1 

Nameplate Output Power Maximum Power in No-Load 

0 to ≤ 50watt 0.062 

> 50 watts 0.165 

5.4.3 Class A EPS Testing Analysis 

5.4.3.1 Survey of EPS Efficiencies in the Market 

DOE purchased and tested commercially available EPS units to determine the range of 

efficiencies in the market and to determine where to focus its analysis of representative units. In 

the market survey (section 5.3) DOE identified 13 EPS-using applications that are important for 

EPSs because they represent a large amount of shipments, consume large amounts of energy, or 

both. As part of the market survey, DOE created a database of EPS models available for 

purchase for each of the 13 applications. DOE purchased a number of models for each 

application such that they would be roughly proportional to the shipments-weighted distributions 

shown in Figure 5.2, without giving overwhelming preference to the largest shipments (e.g., 

cellular phones and notebook computers) and covering applications with the smallest shipments 

(e.g., digital photo frames). 

Accordingly, DOE believes that it has characterized the most popular Class A EPSs in 

terms of shipments and energy consumption as shown in Figure 5.6. DOE applied the 

representative unit criteria in section 5.4.1 to this survey of EPS efficiencies by application to 

select representative units. Detailed explanations and results are available in Appendix 5A of 

this preliminary TSD. 

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40%

50%

60%

70%

80%

90%

100%

0 5 0 100

Average EFficiency [%]

Nameplate Output Power [Watts]

Market Characterization:

Output Power vs. Efficiency

EISA Level

Computer Speakers

Cordless Phones/Answering 

Devices

Digital Photo Frames

External Hard Drives

Inkjet MFDs and Printers

LAN Equipment

Mobile Phones

MP3 Speaker Docks

Notebook Computers

VoIP Adapters

Figure 5.6 Survey of EPS Efficiencies by Application 

5.4.3.2 Evaluation of EPS Efficiencies at Representative Unit Values 

DOE selected specific EPS units to characterize CSL0, CSL1, and CSL3 for each 

representative unit. This section describes the selection process and the characteristics of the 

EPSs chosen to characterize the CSLs. For each representative unit, DOE selected two to three 

EPS test units on which to focus its analysis. DOE purchased test units with values that were the 

same as or very close to the representative unit specifications. For the selected test units, DOE 

commissioned teardowns to estimate their MPCs. For the EPSs that differed slightly from 

representative unit values, DOE normalized their test results through scaling, as specified in 

section 5.4.6. 

The selected EPS test units were evaluated based on their scaled test results and chosen 

so as to best characterize the level based on the following criteria: 

All test units must adhere to the matched-pairs criteria, explained in detail 

below. 

The unit chosen to characterize CSL0 must meet the CSL0 requirements, 

while being as close as possible to CSL0. Units meeting CSL1 criteria do not 

qualify as baseline units. 

The unit chosen to characterize CSL1 must meet the CSL1 requirements, 

while being as close as possible to CSL1. 

The most efficient unit, based on its combination of average efficiency and 

no-load power consumption, characterizes and defines CSL3, Best-in-Market 

(BIM). 

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o	 Units that did not meet CSL1 criteria did not qualify. 

o	 When no single unit was dominant in both dimensions, DOE chose the 

BIM unit so as not to break the matched-pairs approach. 

o	 In addition, the CSL3 unit is chosen such that it is as far away from the 

CSL1 unit as possible in the no-load power and efficiency dimensions. 

o	 In comparing distances in the no-load power and efficiency 

dimensions, the dimension with more effect on annual energy 

consumption (as determined by typical application usage profiles at 

that wattage level) was given precedent. 

There is no test unit to characterize CSL2, Intermediate, because DOE 

developed that level after finalizing test and teardown units. 

There is no test unit to characterize CSL4, ―Max Tech,‖ because it is a 

theoretical unit that does not exist in the market. 

The ―matched pairs‖ approach refers to the pairings of average efficiency and no-load 

power consumption that define the CSLs and EPS efficiency test results. The DOE EPS test 

procedure yields two values in contrast to other DOE test procedures that only yield one value. 

To develop the analysis and ultimately to set standards for EPSs DOE can either combine the test 

values into a single metric, such as annual energy consumption, or it can maintain two separate 

metrics. For this preliminary analysis DOE has chosen to evaluate EPSs using the two metrics 

separately. DOE believes this is the most appropriate way to characterize EPSs because EPSs 

have a wide variety of usage profiles which would affect any weighting of average efficiency 

and no-load power. Further, this approach is important because the cost estimates from the 

teardown apply to the EPS as a whole and cannot be broken down as affecting just active mode 

efficiency or no-load power consumption. 

DOE has structured the CSLs such that they never decrease in stringency in either metrics 

and such that they always increase in stringency in at least one metric. Similarly, DOE uses 

selected test units to characterize the CSLs that have matched pairs of efficiency in that as they 

progress from least efficient to most efficient in terms of active mode efficiency requirements, 

no-load mode power-consumption requirements, or both. As noted in the executive summary, 

DOE is seeking stakeholder comment on the matched pairs approach. 

DOE obtained an estimate of the manufacturer production costs for each selected test unit 

used to characterize the representative units. Below, is a discussion of how DOE selected the 

specific test units for each representative unit. Note that the max-tech data points in Figure 5.7, 

Figure 5.8, Figure 5.9, and Figure 5.10 are only shown for context, as they are not test units, 

but manufacturer responses regarding the best achievable efficiencies and no-load powers in 

EPSs across representative units. 

For the 2.5W, 5V representative unit, DOE considered test units within a wattage range 

of 1.75W to 3W and a voltage range of 4V to 6V that met the criteria of representative product 

class A1. Figure 5.7 shows a plot of the seven units that DOE considered in characterizing the 

2.5W representative unit CSLs. 

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EERE-2008-BT-STD-0005 COMMENT 31
 

#876

#935

#996

#628 #870

#888

#994

Intermediate

0.000

0.100

0.200

0.300

0.400

0.500

58% 60% 62% 64% 66% 68% 70% 72% 74% 76% N o-Load Power [W]

Scaled Average Active-Mode Efficiency [%]

Selected Test Units

Additional Test Units

Intermediate

Max Tech

CSL0

CSL1

CSL2

CSL3

CSL4

Max Tech

Figure 5.7 No-Load Power vs. Scaled Efficiency for 2.5-Watt Units 

DOE considered all EPS units in Figure 5.7, and ultimately selected units #876, #935, 

and #996 to characterize the 2.5-watt CSL0, CSL1, and CSL3 levels, respectively. Unit #876 

was chosen because it was close to the minimum CSL0 efficiency and maximum CSL0 no-load 

power allowances, and was the only unit that maintained a matched-pairs approach. Unit #935 

was selected because it met the CSL1 requirements, and unit #996 was the most efficient unit 

found in the market that also met the CSL1 criteria. Table 5.15 shows the data for the three units 

selected to characterize the 2.5W CSLs. 

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#949

#118

#941

#604

#645

#805

#809

#814

#818

#891

#900

#903

#906

#912

#915

#918

Intermediate

0.000

0.100

0.200

0.300

0.400

0.500

75% 77% 79% 81% 83% 85% 87% 89% N o-Load Power [W]

Scaled Average Active-Mode Efficiency [%]

Selected Test Units

Additional Test Units

Intermediate

Max Tech

CSL0

CSL1

CSL3

CSL4

CSL2

Max Tech

Table 5.15 2.5-Watt Units Used to Characterize the CSLs 

Unit CSL Nameplate Cord Cord No- Average Application 

# Output Length Resistance Load Scaled 

[m] [ohms] Power 

[W] 

Efficiency 

[%] Power 

[W] 

Voltage 

[V] 

876 CSL0 2.4 6.0 1.86 0.31 0.400 61.4 Cordless 

Phones / 

Answering 

Devices 

935 CSL1 2.0 5.0 1.78 0.30 0.170 67.9 Generic 

996 CSL3 1.8 5.0 1.17 0.32 0.103 73.5 Mobile 

Phones 

For the 18W representative unit, all the units considered were exactly at the 

representative nameplate output power and voltage of18W, and 12V, respectively. Figure 5.8 

shows a plot of the sixteen units considered to characterize the 18W CSLs. 

Figure 5.8 No-Load Power vs. Scaled Efficiency for 18-Watt Units 

DOE considered all EPS units in Figure 5.8, and ultimately selected units #949, #118, 

and #941 to characterize the 18-watt CSL0, CSL1, and CSL3 levels, respectively. Unit #949 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

was chosen because it was close to the minimum efficiency and maximum no-load power 

allowances of CSL0, and was the only unit that allowed a matched pairs approach. Unit #118 

was selected because it met, and was close to, the minimum efficiency and maximum no-load 

power allowances of CSL1. Unit #900 was closer to the minimum CSL1 efficiency 

requirements, but much farther than unit #118 in terms of no-load power from the 300mW noload power requirement. Unit #941 was chosen because it was the most energy-efficient unit on 

the market. Even though unit #912 had a slightly lower no-load power, a difference on the order 

of 10mW, unit #941 was over one percentage point higher in efficiency. Table 5.16 shows the 

data for the three units selected to characterize the 18-watt CSLs. 

Table 5.16 18-Watt Units Used to Characterize the CSLs 

Unit 

# 

CSL Nameplate 

Output 

Cord 

Length 

[m] 

Cord 

Resistance 

[ohms] 

NoLoad 

Power 

[W] 

Average 

Scaled 

Efficiency 

[%] 

Application 

Power 

[W] 

Voltage 

[V] 

949 CSL0 18.0 12.0 1.75 0.13 0.330 78.9 Generic 

118 CSL1 18.0 12.0 1.90 0.11 0.270 81.4 Generic 

941 CSL3 18.0 12.0 1.81 0.11 0.100 85.4 Generic 

For the 60W representative unit, the representative nameplate output power and voltage 

were 60W, and 15V, respectively. DOE considered units within a wattage range of 56 to 60W, 

and a voltage range of 15V to 16V. Figure 5.9 shows a plot of the seven units considered to 

characterize the 60W CSLs. 

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#838

#834

#999

#973

#650 #855

#832

0.000

0.100

0.200

0.300

0.400

0.500

84% 85% 86% 87% 88% 89% 90% 91% 92% N o-Load Power [W]

Scaled Average Active-Mode Efficiency [%]

Selected Test Units

Additional Test Units

Intermediate

Max Tech

CSL0

CSL1

CSL3

CSL4

CSL2

Max Tech

Figure 5.9 No-Load Power vs. Scaled Efficiency for 60-Watt Units 

DOE considered all EPS units in Figure 5.9, and ultimately selected units #999, #834, 

and #838 to characterize the 60W CSL0, CSL1, and CSL3 levels, respectively. Unit #999 was 

chosen because it was closest to the minimum CSL0 efficiency and maximum CSL0 no-load 

power allowances. Unit #834 was selected because it was the only unit that met the CSL1 

criteria, and simultaneously allowed unit #838, the most efficient unit on the market, to be 

selected to characterize CSL3 without breaking the matched pairs approach. Table 5.17 shows 

the data for the three units selected to characterize the 60W CSLs. 

Table 5.17 60-Watt Units Used to Characterize the CSLs 

Unit 

# 

CSL Nameplate 

Output 

Cord 

Length 

[m] 

Cord 

Resistance 

[ohms] 

NoLoad 

Power 

[W] 

Average 

Scaled 

Efficiency 

[%] 

Application 

Power 

[W] 

Voltage 

[V] 

999 CSL0 56.0 16.0 1.09 0.08 0.210 85.4 Notebook 

Computers 

834 CSL1 60.0 15.0 1.16 0.04 0.136 87.0 Generic 

838 CSL3 60.0 15.0 1.17 0.04 0.073 88.0 Generic 

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#854 #951

#851

#849 #652

#1004

#1002 #1006

#947

0.000

0.100

0.200

0.300

0.400

0.500

84% 85% 86% 87% 88% 89% 90% 91% 92% N o-Load Power [W]

Scaled Average Active-Mode Efficiency [%]

Selected Test Units

Additional Test Units

Intermediate

Max Tech

CSL0

CSL1

CSL2

CSL3

CSL4

Max Tech

For the 120W representative unit, the representative nameplate output power and voltage 

were 120W, and 19V, respectively. DOE considered units within a wattage range of 119.7W to 

135.1W. Figure 5.10 shows a plot of the nine units considered to characterize the 120W CSLs. 

Figure 5.10 No-Load Power vs. Scaled Efficiency for 120-Watt Units 

DOE considered all EPS units in Figure 5.10, and ultimately selected units #854 and 

#951. Unit #854 was selected to characterize the 120W CSL0 level. Unit #951was selected to 

characterize both the 120W CSL1 and CSL3 levels. Unit #854 was chosen because it was 

closest to the minimum CSL0 efficiency and maximum CSL0 no-load power allowances. It was 

not possible to select two more units, one for CSL1, and one for CSL3 without breaking the 

matched pairs approach. Therefore, unit #951 was selected to characterize both CSL1 and 

CSL3, because it adhered to the matched pairs approach, and was about 1% higher in efficiency 

than either unit #652 or #851. Notebook computers are the most common application that use 

120-watt EPSs and they typically operate a few hours a day. For EPSs for those applications, a 

1% difference in efficiency has a more significant effect on annual energy consumption than less 

than a tenth of a watt in no-load power. Table 5.18shows the data for the three units selected to 

characterize the 120W CSLs. 

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Table 5.18 120-Watt Units Used to Characterize the CSLs 

Unit CSL Nameplate Cord Cord No- Average Application 

# Output Length 

[m] 

Resistance 

[ohms] 

Load 

Power 

[W] 

Scaled 

Efficiency 

[%] 

Power 

[W] 

Voltage 

[V] 

854 CSL0 135.1 19.0 1.78 0.05 0.230 86.5 Notebook 

Computers 

951 CSL1 120.1 19.0 1.80 0.04 0.210 88.4 Notebook 

and Computers 

CSL3 

5.4.4 Class A EPS Teardowns to Estimate Manufacturer Production Cost 

DOE contracted iSuppli Corp. to tear down and estimate the materials cost for select 

units. DOE elected to use iSuppli for its expertise with prices in the consumer electronics 

industry, since those prices are not publicly available. iSuppli provided DOE with the costs for 

all parts listed in the bill of materials, and the labor for assembling those parts into an EPS. DOE 

marked these costs up by the general overhead costs for running a factory to obtain the 

manufacturer’s production cost (MPC), sometimes called the factory cost. DOE used this 

information along with a markup to determine the MSPs. The following subsections describe 

the process for determining MPC and the final results. 

5.4.4.1 Generation of Bills of Materials 

The end result of each teardown is a bill of materials (BOM). iSuppli developed BOMs 

for each unit it tore down. BOMs describe each product part and the manner in which 

manufacturer assembled it. The BOMs describe fabrication and assembly operations in detail, 

including the process cycle times and the labor associated with each manufacturing step. The 

BOM includes the following data fields for each component: 

Location: The assembly/sub-assembly in which the component resides, within the device. 

Quantity: The count of the component 

Component Family: The general type of component such as passive and discrete 

semiconductor. 

Component Type: The specific type of component such as capacitor and diode.
 

Manufacturing Name and Part Number: The component’s name and number.
	

Component Description: Component-specific information such as ―Film - Radial, Dipped, 

0.47uF, 10%‖ and ―Zener - 34.6V, 2mA‖ 

Markings: Any visible markings used in component identification, such as ―Logo, 474K, n, 

450MFF4‖ and ―TZX, 36, C‖ 

Package Dimensions: These include component form, diameter, length, height, width and pin 

count. 

Per Component Cost: The cost to the EPS manufacturer of the individual component at a 

specified production volume. 

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Production Cost Non-Production Cost

Direct

Labor

Direct

Materials Overhead Selling General &Administrative R&D Interest Profit

Full Cost of Product [$]

Insertion Method: Either insertion by hand or automated insertion.
 

Per Insertion Cost (Auto): The cost of automated insertion for the component.
 

Hand Insert Cost: The cost of inserting the component by hand, which is calculated from the 

insert time and the pay rate for the laborer. 

Data Sheet Links: Any data sheets for the components used in determining pricing.. 

5.4.4.2 Cost Structure of the Spreadsheet Models 

The manufacturing cost assessment methodology used a detailed, component- focused 

technique for calculating the manufacturing cost of a product (direct materials, direct labor, and 

the overhead costs associated with production). The first step in the manufacturing cost 

assessment was the creation of a complete BOM from the disassembly of the units selected for 

teardown. The units were dismantled, and each part was characterized according to 

manufacturer, dimensions, material, and quantity. iSuppli based its assumptions on the sourcing 

of parts and in-house fabrication on its industry experience and discussions with manufacturers. 

The last step was to convert this information into MPC values. To perform this task, iSuppli 

sums the direct material costs and the conversion costs, to which DOE added a general factory 

overhead markup, to determine the total MPC for each unit. Figure 5.11 shows the general 

breakdown of costs associated with manufacturing a product. 

Figure 5.11 Full Cost of Product: Breakdown of Production and Non-Production Costs 

5.4.4.3 Production Volumes Assumptions 

A manufacturer’s production volumes vary depending on several factors, including 

market share, the type of product produced, and if the manufacturer produces other similar 

products. iSuppli estimated unit costs using three volume assumptions: annual production 

volume, production lifespan, and lifetime production volume. Annual production volume 

specifies the number of units a manufacturer produces of the product each year, which affects 

component costs. Production lifespan specifies the number of years that a manufacturer 

produces a product, which affects the amount of time over which the manufacturer can amortize 

equipment costs. The lifetime production volume is the total number of units produced by the 

manufacturer, which is the product of the annual production volume and production lifespan. 

Based on their industry knowledge, iSuppli and DOE jointly developed estimates of 

production volumes and production lifespans for each representative unit. iSuppli indicated that 

their cost-estimation model was sensitive only to large differences in production volume so the 

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values provided were rough estimates. Furthermore, iSuppli preferred to use lifetime production 

volumes for its cost estimates, whereas most manufacturers preferred annual production 

volumes. As noted in section 5.4.6, DOE considered developing scaling relationships between 

cost and production volume, but did not do so because it was not needed. In interviews, 

manufacturers indicated to DOE that production volume, not production lifespan, was the major 

factor affecting price. Consequently, the manufacturer interviews did not address production 

lifespans. 

5.4.4.4 Teardown Results 

iSuppli performed teardowns for all of the EPSs that DOE chose to characterize the 

representative units and each CSL as specified in section 5.4.3.2. For each of those EPSs, Table 

5.19 indicates the estimated MPCs after applying the general factory overhead markup to 

iSuppli’s costs. 

Table 5.19 iSuppli Teardown Cost Estimates 

Unit# Representative 

Unit CSL MPC 

Output 

Cord 

Cost 

Output 

Cord 

Length 

[m] 

Lifespan Prod. 

Volume per 

iSuppli 

Teardown 

(Units) 

876 

935 

996 

2.5W CSL0 $1.42 $0.11 1.86 6,000,000 

2.5W CSL1 $1.71 $0.17 1.78 6,000,000 

2.5W CSL2 $1.12 $0.12 1.17 6,000,000 

949 

118 

941 

18W CSL0 $4.18 $0.23 1.75 6,600,000 

18W CSL1 $4.11 $0.33 1.90 6,600,000 

18W CSL2 $3.37 $0.25 1.81 6,600,000 

999 

834 

838 

60W CSL0 $4.19 $0.20 1.09 7,100,000 

60W CSL1 $5.82 $0.24 1.16 7,100,000 

60W CSL2 $6.15 $0.23 1.17 7,100,000 

854 

951 

120W CSL0 $12.55 $0.65 1.78 8,000,000 

120W CSL1, 

CSL2 $9.18 $0.25 1.80 8,000,000 

Additional Teardowns Data (Not Used To Characterize CSLs): 

867 

809 

650 

853 

1004 

* N/A $1.59 $0.14 1.83 6,000,000 

18W N/A $3.41 $0.37 1.51 6,600,000 

60W N/A $7.83 $0.44 1.75 7,100,000 

120W N/A $11.53 $0.26 1.70 8,000,000 

120W N/A $7.38 $0.23 1.11 8,000,000 

*Unit #867 was a low-voltage unit, because its nameplate output voltage was 5V, and nameplate output current was 

0.55A. 

5.4.5 Class A EPS Manufacturer Interviews 

In 2009 and 2010, on behalf of DOE, Navigant Consulting, Inc. (Navigant Consulting) 

interviewed a total of eight manufacturers of EPSs, integrated circuit (IC) controllers for EPSs, 

and original equipment manufacturers (OEMs) that use EPSs to obtain data on EPS efficiencies 

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and costs. At the request of some manufacturers, Navigant Consulting entered into nondisclosure agreements whereby it could present to DOE general information about the EPS 

market and technology, but no confidential data specific to any individual manufacturer. 

Navigant Consulting aggregated the manufacturer data (detailed in Appendix 5C); the resulting 

cost-efficiency data is presented in section 5.4.8. 

Before the interviews, Navigant Consulting gave each manufacturer an interview guide 

(Appendix 5C) that included possible questions to be asked during the interview and tables 

detailing efficiency and no-load values for the manufacturers to populate with associated costs. 

Navigant Consulting asked manufacturers to provide feedback regarding the representation of 

the market and to supply any data that could improve DOE’s estimates and assumptions. 

Navigant Consulting’s questions included the following: 

1.	 What are the highest volume products that you sell? Please include output voltage, 

output power, and application. 

2.	 Please provide a list of any additional applications for which you sell EPSs or EPS 

components. 

3.	 Are there any specific design concerns unique to certain applications? 

4.	 What are the typical mark ups from the EPS bill of materials (BOM) to the final 

consumer purchase price?
 

5.	 The U.S. Department of Energy (DOE) is required to set no-load and active mode energy 

efficiency standards for external power supplies. Is there a correlation between no-load 

power and active mode power efficiency? If not, can the two be optimized separately? 

6.	 What are your design options (e.g. Schottky diodes, improved components, better core 

material) for improving active mode efficiencies and no-load power consumption? 

Manufacturers provided general information and data specific to representative units. The 

following subsection details Navigant Consulting’s methodology for aggregating manufacturer 

data so that it was presentable to DOE. The subsequent subsections provide summaries of 

manufacturers input on issues affecting the engineering analysis. 

5.4.5.1 Aggregation Methodology 

Navigant Consulting collected manufacturer cost-efficiency data for each representative 

unit and aggregated manufacturer responses, which it presented to DOE. EPSs are unique 

because their CSLs are defined by energy consumption parameters: average efficiency and noload power. Hence, Navigant Consulting obtained costs for each CSL defined by a combination 

of EPS efficiency and no-load power. In the interview guide, Navigant Consulting asked 

manufacturers for costs at the specific CSLs for each representative unit. However, 

manufacturers provided costs over a range of efficiency and no-load power values because they 

generally preferred to tie in costs to their own product lines, which often had efficiency and noload power values slightly different from the CSL values. Consequently, Navigant Consulting 

performed three steps on the manufacturer data before providing DOE with aggregated results: 

(1) normalize the data to be consistent; (2) develop equations to generalize the data; and (3) 

apply the CSL values to the equations to determine aggregate costs. 

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Since manufacturers had used various assumptions in providing their data, Navigant 

Consulting normalized the manufacturer data to ensure that the results from the manufacturers 

were comparable. For example, some manufacturers had not factored in an output cord. To 

account for the possible effects on cost and efficiency, the data points were adjusted, assuming 

the standard 1.66m cord length. In addition, some manufacturer data assumed nameplate output 

voltages or wattages that were slightly different than the representative unit values. For details 

on scaling, please see Section 5.4.6. 

First, the manufacturer costs which were given at the BOM or MPC points in the value 

chain, needed to be marked up to MSP (per Section 5.4.6.6). Second, Navigant Consulting 

ensured that the manufacturer datasets all had an MSP of $0 for baseline units. Shifting the 

manufacturer data to the same CSL0 baseline values, meant that the incremental MSP costs at 

CSLs above baseline, were based on the same $0 reference point. This was necessary because 

scaling the datasets sometimes resulted in baseline values that were not $0. 

The normalized manufacturer data was aligned at CSL0 and covered a range of values for 

the other CSLs, as shown in Figure 5.12 and Figure 5.13. Both figures contain illustrative 

values to show the kind of values that were obtained during manufacturer interviews. Individual 

manufacturer data points cannot be revealed due to non-disclosure agreements (NDAs) with 

participating manufacturers. The example is for the 2.5W representative unit. Though the 

following discussion focuses on the 2.5W unit, the reasoning is the same for the 18W, 60W, and 

120W representative units. CSL2 was introduced after manufacturer interviews, and hence the 

costs used to characterize CSL2 were interpolated based on data from the other CSLs. Hence the 

tick marks on the x-axis represent the CSL efficiency values, with the CSL2 tick mark not 

corresponding to its own set of manufacturer data. 

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$0.00

$0.05

$0.10

$0.15

$0.20

$0.25

$0.30

$0.35

55% 60% 65% 70% 75% 80%

Manufacturer Selling Price [$]

Average Active Mode Efficiency [%]

Cost vs. Efficiency

Mfr Data Points for CSL0

Mfr Data Points for CSL1

Mfr Data Points for CSL3

Mfr Data Points for CSL4

Figure 5.12 Sample efficiency and MSP Manufacturer Data for the 2.5W Representative 

Unit. 

*The data presented in this plot is for illustrative purposes only. It is not actual manufacturer data. 

5-29 

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$-

$0.05 

$0.10 

$0.15 

$0.20 

$0.25 

$0.30 

$0.35 

$0.40 

4 0 140 240 340 440 540

Manufacturer Selling Price [$]

N o-Load Power [mW]

Cost vs. No-Load Power

Mfr Data Points for CSL0

Mfr Data Points for CSL1

Mfr Data Points for CSL3

Mfr Data Points for CSL4

Figure 5.13 Sample no-load power and MSP Manufacturer Data for the 2.5W 

Representative Unit. 

*The data presented in this plot is for illustrative purposes only. It is not actual manufacturer data. 

The 2.5W CSL0, CSL1, CSL2, CSL3, and CSL4 average efficiency values were 58.3%, 

67.9%, 71.0%, 73.5%, and 74.0%, respectively. The illustrative data in Figure 5.12 shows that 

though the CSL1 efficiency was 67.9%, manufacturer efficiencies might vary significantly, with 

efficiencies in the range of 65% to 70%. The illustrative data in Figure 5.12 does not exaggerate 

the variation present in manufacturer responses. Similarly, Figure 5.13 illustrates the type of 

manufacturer data that Navigant Consulting obtained for MSP versus no-load power for the 

2.5W representative unit. 

This set of manufacturer data presented two challenges: First, Navigant Consulting had to 

account for data in three dimensions (efficiency, no-load power, and cost); Second, Navigant 

Consulting had to develop an aggregate response based on the variation in the manufacturer data 

along all three dimensions for each CSL of each representative unit. 

To address these challenges, it was necessary to fit curves to the manufacturer data. 

Curve fitting allowed Navigant Consulting to estimate an MSP at the CSL efficiency and no-load 

power values, and allowed for aggregation of the manufacturer data. To explain Navigant 

Consulting’s approach of aggregating the data in three dimensions, it is helpful to first illustrate 

how the approach works in two dimensions. 

Figure 5.14 illustrates the two-dimensional approach to aggregating manufacturer data. 

A quadratic curve is fit to the data in each representative unit, and forced to pass through $0 at 

CSL0. The linear fit is of the form Z=a+bX+cX2

, where Z represents the MSP, X represents the 

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efficiency, and a least-squares fit determines the parameters a, b, and c. Thus, the aggregate 

MSP at a particular CSL, is determined by applying the efficiency value to the equation. This is 

shown in Figure 5.14 by the black circles. 

$0.00

$0.05

$0.10

$0.15

$0.20

$0.25

$0.30

$0.35

55% 60% 65% 70% 75% 80%

Manufacturer Selling Price [$]

Average Active Mode Efficiency [%]

Cost vs. Efficiency

Mfr Data Points for CSL0

Mfr Data Points for CSL1

Mfr Data Points for CSL3

Mfr Data Points for CSL4

Aggregated Cost Used 

to Characterize CSL

Figure 5.14 Illustration of Aggregation Method in Two Dimensions for the 2.5W 

Representative Unit 

*The efficiency and MSP data presented in the plot is not actual manufacturer data; it is only for illustrative 

purposes. 

The same approach is also applicable to no-load power and MSP values, as shown in 

Figure 5.15. In this scenario, the quadratic fit would have the form Z=a+bY+cY2, where Z 

would represent the MSP output, X would represent the no-load power input, and the parameters 

a, b, and c would be determined from the least-squares fit. 

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$-

$0.05 

$0.10 

$0.15 

$0.20 

$0.25 

$0.30 

$0.35 

$0.40 

4 0 140 240 340 440 540

Manufacturer Selling Price [$]

N o-Load Power [mW]

Cost vs. No-Load Power

Mfr Data Points for CSL0

Mfr Data Points for CSL1

Mfr Data Points for CSL3

Mfr Data Points for CSL4

Aggregated Cost Used 

to characterize CSL

Figure 5.15 Illustration of Aggregation Method in Two Dimensions for the 2.5W 

Representative Unit 

*The no-load power and MSP data presented in the plot is not actual manufacturer data; it is only for illustrative 

purposes. 

In the original problem, the MSPs were dependent on both the efficiencies and no-load 

powers. Hence, this is a three-dimensional problem where the independent variables are 

efficiency and no-load power, and the dependent variable is MSP. To obtain aggregate MSPs at 

the CSL efficiencies and no-load powers, Navigant Consulting fit three-dimensional quadratic 

surfaces to the manufacturer data (the analog of the quadratic curves in the two-dimensional 

examples). As was done in the two-dimensional examples in Figure 5.14 and Figure 5.15, one 

quadratic surface was fir for each representative unit. Each quadratic surface was a least-squares 

fit of the MSP, efficiency, and no-load power data, with the constraint that it pass through $0 at 

CSL0. The form of the equation for the surface was Z=a+bX+cX2+dY+eY2+fXY+gX2Y+hXY2, 

where Z represents the MSP output, X represents the efficiency input, Y represents the no-load 

power input, and the parameters a, b, c, d, e, f, g, and h would be determined from a least-squares 

fit. After fitting the surface to the manufacturer data of each representative unit, Navigant 

Consulting applied the CSL efficiencies and no-load powers to obtain the aggregate MSPs. 

5.4.5.2 Factors that affect conversion efficiency 

Conversion efficiency is determined by EPS active-mode power consumption, which is 

comprised of power lost through components as it flows through the EPS as well as power 

consumed by EPS overhead control circuitry. Particularly for EPSs with higher nameplate 

output powers, EPS control circuitry consumes significantly less power than what is lost as 

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power passes through components. Thus, manufacturers indicate that they reduce power 

consumption by focusing their efforts on the power consuming components. 

Design options for reducing components’ power consumption can be divided into two 

categories: (1) improvements to the topology and IC controller and (2) improvements to 

particular components in the EPS. The combination of topology and IC controller has the most 

influence on EPS efficiency because the topology dictates which components are used in the EPS 

and the controller coordinates how power flows. In general, manufacturers would use a flyback 

topology for most EPSs, with two exceptions. For the baseline model of the 2.5W representative 

unit, they would use a ringing-choke converter, which does not employ an IC controller. For the 

60W and 120W representative units, they would use a resonant topology such as a half bridge 

converter or an LLC (inductor-inductor-capacitor) converter for the higher-efficiency CSLs. 

The IC controller dictates how power flows through the EPS by monitoring the EPS 

output as well as other conditions. Using those input signals, the controller employs algorithms 

to control a metal-oxide-semiconductor field-effect transistor (MOSFET) switch, which, in turn, 

controls the input power that flows from mains to the primary side of the EPS’s transformer. IC 

controllers can use algorithms such as zero-voltage switching (ZVS) and frequency fold-back to 

reduce EPS power consumption. In ZVS, the controller opens and closes the switch only when 

there are 0 volts across it, which greatly reduces conduction losses in the MOSFET. A controller 

employs frequency fold-back during light loading conditions by reducing the frequency at which 

it turns on the MOSFET, minimizing the switching losses in the MOSFET. In addition to these 

methods, the IC controller can also replace functions provided by discrete components. IC 

manufacturers indicate that they typically price IC controllers based on the value of their high 

efficiency and ability to replace discrete components. 

Among the discrete components that manufacturers would improve to increase 

efficiency, the two most often cited were the switching MOSFET and the output rectifier. 

Switching MOSFETs have two types of losses: conduction losses and switching losses. 

Conduction losses can be reduced by reducing the resistance from the drain to the source of the 

MOSFET while turned on, referred to as the RDS_ON. Typically, increasing the size of the silicon 

transformer or improving its material properties reduces RDS_ON. Switching losses are the losses 

caused by activating and deactivating the MOSFET switch, typically governed by gate 

capacitance. Gate capacitance is reduced through improvement of material properties and use of 

smaller silicon chips. To improve MOSFETs, manufacturers typically indicated that they would 

pay for larger, better quality silicon. 

The output rectifier is the other key component that manufacturers would improve. There 

are three types of output rectifiers: regular diodes, Schottky diodes, and synchronous rectification 

MOSFETs. The power consumption through the output rectifier is governed by: 

Pconsumed = Vdiode × Iout. Regular diodes are the cheapest and least efficient. Typically, regular 

diodes have a diode voltage drop of approximately 1V. Schottky diodes are more expensive and 

have a diode voltage drop of approximately 0.3V, thus, for the same output current, their power 

consumption is significantly less. A synchronous rectification circuit uses a controller and a 

MOSFET instead of a diode so that the MOSFET provides the functionality of a diode without 

the voltage drop. The benefit of this arrangement is that the power consumed by the MOSFET is 

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typically much lower than the power consumed even by a Schottky diode; however, the 

MOSFET and its control circuit are more expensive than Schottky diodes. The benefit to using 

synchronous rectification for EPSs becomes diminished at higher output voltages (above 15V) in 

which case manufacturers sometimes found Schottky diodes to be the best design option. 

As a last step in improving efficiency, manufacturers would switch to a thicker output 

cable, or reduce the cable length. Changing wire gauge is generally more expensive than minor 

component changes on the printed circuit board (PCB), so manufacturers first focus on the PCB 

to improve efficiency at low cost. If active-mode efficiency is still below a desired level 

manufacturers will change the cable to get a slight boost in efficiency, because at that point in the 

design process, it is easier than redesigning the whole PCB. 

5.4.5.3 Factors that affect no-load power consumption 

The IC controller has the most influence over no-load power consumption because it 

determines which parts of the EPS turn off in no-load mode. The most common technique 

employed by IC controllers to reduce no-load power consumption is to use cycle skipping or 

burst mode. In active mode, the IC controller turns on the switching MOSFET often at rates 

greater than 20 kHz. In no-load mode, the controller can skip cycles, thus saving power that 

would have been consumed by MOSFET switching losses. When the controller skips many 

cycles – possibly even for seconds at a time – the EPS is said to operate in burst mode. The 

number of cycles skipped is limited by the turn on time, which is how quickly the EPS needs to 

be able to provide full power to the load. Better IC controllers can achieve no-load mode power 

consumption in the range of 100mW to 200mW, well below the EISA maximum limit of 

500mW. Typically the increase in cost is minimal to fabricate an IC controller that reduces noload power consumption; IC manufacturers charge a price for this feature that reflects its value in 

the market. 

For higher power EPSs (60W and 120W) manufacturers indicated another step that they 

would take to reduce no-load power consumption: they would employ a small 1-watt 

―housekeeping‖ power supply. In no-load mode, an EPS must monitor when there is an output 

load and must meet the load’s power demands in a timely manner. For higher power EPSs, the 

first step to providing the monitoring function while reducing no-load power consumption is to 

use an IC controller with cycle skipping and burst mode. However, that controller will still need 

to activate all parts of the EPS during the bursts when it checks the presence of a load. This can 

consume significant amounts of power. As an alternative, manufacturers can include an 

additional housekeeping power supply circuit in the EPS that can monitor the output load and 

quickly activate the main EPS when it needs to provide a load. The housekeeping power supply 

will have a much smaller transformer than the one used during active mode. This reduction in 

size will reduce quiescent losses. Often the housekeeping supply is a cost-effective way of 

achieving very load no-load power consumption for a higher power EPS. 

5.4.5.4 Factors that affect cost 

Manufacturers identified the mark up chain within an EPS manufacturer as beginning as 

a bill of materials (BOM) that enters a factory to a product valued at the manufacturer’s 

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production cost (MPC) as it leaves the factory to the manufacturer selling price (MSP) – the 

price at which the EPS manufacturer sells the EPS. Some manufacturers referred to MPC as the 

―factory cost‖ since it is the cost of the EPS existing the factory, typically located in China. In 

general, manufacturers provided cost data at the MPC level and indicated a typical mark up of 

about 1.3 from MPC to MSP, although the range of markup varied from 1.2 to 1.85. 

Manufacturers also indicated that markups varied with efficiency – i.e., EPSs qualifying for 

Energy Star had higher markups. Nonetheless, the analysis only uses the markups for baseline 

EPSs because that best reflects what consumers would pay were DOE to implement a standard. 

In addition, manufacturers provided data on cost scaling. They unanimously indicated 

that cost scaling is unnecessary between EPSs with similar nameplate output power values 

(within approximately 10% of each other). Specifically, many manufacturers provided data for 

65W EPSs, which they believe are more common than 60W EPSs, the representative unit. 

Nonetheless, they believe that only a few of the components between the two EPSs would be 

different and the cost difference between those components is negligible. 

In other cases, manufacturers provided data for units that were significantly different from the 

representative unit values. One manufacturer provided data for a 5W EPS and indicated that the 

costs for a comparable 2.5W EPS would be half. Another manufacturer provided data for a 

100W EPS and indicated that the costs for a 120W EPS would be 10% higher. 

5.4.5.5 Factors to consider for candidate standard levels 

Manufacturers had a consensus view that using matched pairs as the basis for the CSLs is 

a valid approach. Specifically, they indicated that average efficiency and no-load power 

consumption vary independently, except at very high efficiencies – i.e., when average efficiency 

is very high (above 90% for EPSs over 50W) or no-load power consumption is very low (less 

than 30mW). 

5.4.5.6 Factors to consider when interpreting the test and teardown results 

Manufacturers have a consensus view that cost increases with efficiency when all other 

characteristics of EPS design are held constant; hence, the manufacturers’ cost-efficiency curves 

all have positive slopes. They noted, however, that conducting a cost-efficiency analysis by 

purchasing EPSs might yield questionable results because it is all but impossible to hold constant 

all design characteristics, other than cost and efficiency, for different EPSs in the market. 

Example EPS characteristics that they noted might vary: 

Maximum case temperature 

Maximum component temperatures 

Component de-rating (how close a component operates to its maximum rating) 

Hold-up time (how long the EPS outputs power after being disconnected from mains) 

Output voltage regulation 

Efficiency requirements at non-US voltages 

Protection features (e.g., shutting down during short circuit conditions) 

Maximum ambient temperature 

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Most of these characteristics affect the reliability of the EPS (i.e., when it fails) and the 

tolerance of the EPS to different electronic and environmental conditions (e.g., how long the EPS 

provides output power after being unplugged from mains; whether the EPS operates in 110 

degree heat). A further complication is that many of these factors significantly affect cost and 

efficiency, but do not all affect it in the same way – i.e., characteristics leading to more reliable 

and expensive EPSs may make EPSs more efficient in some cases, but less efficient in others. 

For instance, increasing component de-rating makes an EPS more expensive and reliable, but 

less efficient. De-rating is the value for a component, such as a transistor, that specifies the 

difference between the anticipated maximum voltage the transistor will experience under normal 

operating conditions in the EPS versus the maximum rated value indicated by the transistor 

manufacturer. Often transistors in EPSs are expected to endure 400V drops and will often have a 

maximum rating of 500V or 600V. Of course, the 600V transistor is more expensive, but it is 

also less efficient than the 500V one. So if two EPSs were identical other than their transistor 

de-ratings, their cost-efficiency curve would have a negative slope. However, an EPS with a 

600V transistor will be more robust. In other cases, a higher-quality specification, such as 

lowering case temperature, would tend to lead to improved efficiency. Ultimately, the OEM 

specifies these characteristics so that the EPS functions as desired with the OEM’s application or 

range of applications. EPSs are used with a diversity of applications; thus, their specifications 

are diverse, which complicates an analysis of cost and efficiency based on commercially 

available units. 

To deal with this issue in the test and teardowns section of the preliminary analysis, DOE 

notes the intended application for the EPS test units selected to characterize the representative 

units. DOE also had its SME conduct evaluations to compare the selected test units. In 

particular, the SME focused on the more important characteristics that manufacturers mentioned. 

For future analyses, manufacturers suggested purchasing EPSs from similar manufacturers for 

similar types of products. For example, for the 60-watt representative unit analysis, DOE might 

only buy EPSs sold with laptops from major manufacturers since they tend to have similar 

requirements. Currently, the 60-watt representative unit analysis includes test units for generic 

applications that might be lower quality than laptop EPSs. However, even if DOE were to 

narrow the unit selection, manufacturers still expect that differences in the EPS specifications 

between similar OEMs could make it difficult to isolate cost and efficiency so as to yield a costefficiency curve with a positive slope. In addition, DOE’s SMEs indicate that the redesign 

process of an EPS represents a fixed cost which the test-unit teardown analysis cannot account 

for. 

5.4.6 Class A EPS Scaling Relationships 

DOE developed scaling relationships that it used both to analyze representative unit data 

as well as to scale CSLs from product class A1 to other product classes. In general, the scaling 

methods for representative unit data were detailed whereas the scaling methods for CSLs were 

simpler. For the representative unit data DOE adopted the more detailed approach because the 

detailed methods provide enhanced accuracy, which was paramount, as it was the basis for later 

analyses, including the LCC and NIA. For the CSL equations, DOE adopted the simpler 

approach so that stakeholders could more easily evaluate the CSLs. As noted in the executive 

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summary, DOE is seeking stakeholder comment on these approaches and may develop more 

detailed CSL equations in response to stakeholder comment. 

For the purposes of the preliminary analysis, DOE developed CSL equations that have 

the general form Y=a*ln(Pout) + b*Pout+c, for each of the nameplate output power segments, 

where Y indicates the efficiency or no load-power requirement; Pout indicates the nameplate 

output power; and a, b, and c indicate the specific parameters defined in the respective CSLs. As 

explained in this section, DOE has determined that output cord and output voltage also have an 

effect on efficiency. Thus DOE could have included terms in the CSL equations for output cord 

and output voltage although that would have resulted in much more complicated equations. For 

the NOPR, DOE intends to maintain the equations in this form, which is based on output power 

exclusively. 

In sections 5.4.3, 5.4.4, and 5.4.5 DOE presents the test data, teardown data, and 

manufacturer data that it used as the basis of this analysis. Wherever possible, DOE selected test 

units that had the same characteristics as the representative units. Similarly, it sought data from 

manufacturers at the representative unit values. However, in some cases, test units and 

manufacturers’ data were slightly different from the representative unit specifications. For those 

cases DOE developed detailed scaling relationships so that the data would be most applicable to 

the representative unit analysis. 

Specifically, the Class A EPS engineering analysis characterizes the cost-efficiency 

relationship using average efficiency in active mode, power consumption in no-load mode and 

MSP. DOE did not develop scaling relationships for no-load mode power consumption because 

it is minimally affected by EPS representative unit characteristics. DOE considered developing a 

scaling relationship for cost by production volume. Specifically, for the representative units, 

DOE and iSuppli, the contractor that DOE employed to carry out the teardowns, developed 

estimate production volumes that were on the order of approximately 1M units shipped per year. 

iSuppli indicated that prices did not change appreciably over that range, hence scaling by 

production volume is not necessary. Thus, to scale data with different production volumes to the 

representative unit’s production volume, DOE did not change the data’s costs, which DOE 

considers to be ―scaling with no effect.‖ 

For the efficiency and MSP characteristics, DOE developed the following scaling 

relationships: 

Efficiency by nameplate output power. DOE scaled efficiency by output power 

using the EISA 2007 standard and Energy Star 2.0 specification, which follow the 

market trend of increasing efficiency with increasing output power. (Section 

5.4.6.1). 

Efficiency by nameplate output voltage. For EPSs of a given nameplate output 

power, lower nameplate output voltage results in higher current-associated losses 

and lower efficiency. DOE analyzed units with the same nameplate output power 

and different nameplate output voltages to characterize this relationship. DOE 

also evaluated a voltage scaling approach based on Energy Star 2.0, for lowvoltage units (Section 5.4.6.2). 

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Original 

Efficiency

Original Cost

Scaled Efficiency 

and Cost

Scaling for 

Cord Length

Scaling for 

Output 

Power

Scaling for 

Output 

Voltage

Scaling for 

Cord Length

Scaling for 

Output 

Power

Markups

Efficiency by output cord length. Longer output cords provide consumers with 

the added utility of being able to operate the product farther from mains. Longer 

output cords also have higher losses and are more expensive. DOE analyzed 

output cords to characterize this relationship. (Section5.4.6.3). 

Cost by nameplate output power. EPSs with higher nameplate output powers 

provide consumers with the added utility of being able to provide power to more 

power-demanding products. EPSs with higher nameplate output power also have 

more and larger components and, consequently, cost more. (Section 5.4.6.4). 

Cost by output cord length. Longer output cords are also more expensive. DOE 

analyzed output cords to characterize this relationship. (Section 5.4.6.5). 

Markups. Test and manufacturer data costs at different points in the value chain 

represent different stages in the sale of an EPS. DOE characterized these markups 

in order to compare costs at the same stage in the value chain, namely MSP 

(Section 5.4.6.6). 

Though in many cases the data did not require applying all of the scaling steps, all the 

scaling steps are nonetheless illustrated in Figure 5.16 in the order that they would be applied. 

Figure 5.16 Scaling Steps to Normalize Efficiencies and Costs 

5.4.6.1 Scaling Efficiency with Output Power 

The practically achievable efficiency of an EPS depends on its nameplate output power, 

with lower-power EPSs tending to exhibit lower active-mode efficiencies than their higherpower counterparts. DOE characterized this relationship using the EISA 2007 standards 

equation and ENERGY STAR 2.0 standard voltage specification equation that describe this 

market trend; these equations are the same as CSL0 and CSL1 equations, shown in Table 5.5 

and Table 5.7, respectively. 

DOE used these equations as references relative to which it scaled data. To scale the 

data, DOE ensured that the ratio between the original data point and the reference equations 

remained constant, as shown in Figure 5.17. The figure shows how the efficiency data point 

maintains the same relative relationship between the EISA 2007 and ENERGY STAR 2.0 

equation as it is scaled from 70% efficient at 5 watts to 75% efficient at 10 watts. DOE believes 

this scaling approach is appropriate because it ensures that the EPS data does not cross CSLs as 

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it scales between output powers. Further, by comparing the data relative to two levels, rather 

than shifting based on the absolute difference from one level, there is a lower risk of the data 

being scaled to unrealistic values. 

55%

60%

65%

70%

75%

80%

85%

0 2 4 6 8 10 12 14

Efficiency [%]

Nameplate Output Power [W]

EISA 2007 ENERGY STAR 2.0

Shift Output Power 

Original 

value

New

value

Figure 5.17 Scaling an EPS efficiency data point with nameplate output power 

DOE developed the following equation to perform the scaling: 

E NEW EISA NEW

E ORIGINAL EISA ORIGINAL

UNIT ORIGINAL EISA ORIGINAL

UNIT NEW EISA NEW *_ _

*_ _

_ _

_ _

Where 

UNIT

, EISA, and 

E*

are the efficiencies of the unit under analysis at an output power, 

the corresponding EISA 2007 efficiency, and ENERGY STAR efficiency, respectively. 

―ORIGINAL‖ and ―NEW‖ denote whether the values are at the unit’s original nameplate output 

power or new nameplate output power. 

In certain instances scaling by output power does not have an effect. For data where both 

the ORIGINAL nameplate output power and the NEW output power are greater than or equal to 

51W, there will be no effect on the efficiency value. This is because both the EISA and Energy 

Star 2.0 equations are constant for output powers at or above 51W. Hence, the efficiency value 

output from the scaling equation will be identical to the efficiency value used as the input. 

Unit #876 is an example of an instance where it was necessary to scale based on output 

power. Unit #876 was chosen for the 2.5W CSL0 representative unit (see Table 5.15). Since 

this unit had a nameplate output power of 2.4W, it was necessary to scale its efficiency to that of 

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an equivalent 2.5W unit. The original, tested average active-mode efficiency of unit #876, which 

was 61.0%, was first scaled using the output cord scaling procedure (see Section 5.4.6.3), to 

61.1%. Then, after applying the output power scaling, the efficiency was scaled from 61.1% to 

61.4%. The magnitude depends in general on how close the original nameplate output power is 

to the representative output power and the slope of the curves at those values. 

5.4.6.2 Scaling Efficiency with Output Voltage 

DOE used two methods for output voltage scaling. The first method was simple and 

based Energy Star 2.0. The second method was more detailed and based on test data. DOE 

applied the first method to scale CSL equations between the basic voltage and low-voltage 

product classes. DOE applied the second method to scale data for the representative unit 

analysis. As noted in the executive summary, DOE is seeking stakeholder comment on this 

approach. Herein DOE describes the two methods for output voltage scaling in more detail. 

The first method involved using the differences between the EPS Energy Star 2.0 

efficiency equations for basic and low-voltage (see Section 5.4.10.2 for details). This method 

was used in scaling CSL efficiency equations from the basic voltage product classes (A1 and A3) 

to the low-voltage product classes (A2 and A4). This method was particularly appropriate for 

product class scaling for at least two reasons. First, the low-voltage product class definitions 

coincide with the Energy Star 2.0 definitions for basic voltage and low voltage. Second, using 

the Energy Star 2.0 equations, which span the entire range of nameplate output powers, allowed 

DOE to set a standard for efficiency at all nameplate output powers, not just those near the 

representative unit values, where the test data method is focused. 

DOE believes that the Energy Star 2.0 scaling method was inappropriate for use directly 

on representative unit data. Specifically, unlike the Energy Star 2.0 standard voltage equation, 

the Energy Star 2.0 low-voltage efficiency equation applies to EPSs with output voltage less than 

6V, and output current greater than or equal to 0.55A. Thus, as the Energy Star 2.0 ―standard 

voltage‖ and ―low-voltage‖ labels imply, the Energy Star 2.0 efficiency equations only provide a 

coarse, two-bin, basis for examining the effects of differing output voltages on EPS efficiencies. 

Thus, this first method was not applicable for scaling the representative unit data to the 

appropriate representative unit voltages at fine scales. 

DOE developed the second, more complex method based on units it had tested in the 

market near representative unit values. This second method was particularly useful for scaling 

representative unit data by output voltage. Although DOE could theoretically extend this method 

to develop scaling relationships at other nameplate output powers, DOE did not do so because of 

the significant complexity involved. In addition, even if DOE were to extend this method to all 

output powers, it would still not address the issue of how to scale a basic voltage product class to 

a low voltage product class. This is because DOE’s output voltage scaling method requires an 

exact target output voltage to scale to, and the low-voltage product class only indicates that the 

output voltage is less than 6 volts. The following is an introduction to this second method, which 

DOE used to scale representative unit data by output voltage: 

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EPS power consumption is related to (1) power consumption due to overhead circuitry 

and (2) losses as power flows through the EPS. For an EPS of a given output power, overhead 

circuitry consumes power independent of EPS output voltage. In contrast, losses as power flows 

through the EPS are directly related to output voltage, because the combination of output voltage 

and output power determines output current. For instance, resistive losses are related to output 

current by I2

*R; losses due to diode drops are related by I*Vdiode. 

DOE analyzed this relationship for each of the four representative units by analyzing EPS 

product families. Manufacturers create EPS product families by designing an EPS for a specific 

nameplate output power and a range of nameplate output voltages. Consequently, product 

families are comprised of EPSs that are very similar, only differing in output voltage. DOE 

purchased and tested (using the DOE EPS test procedure) all of the EPS product families it could 

locate with nameplate output power close to or at the representative unit output powers. For 

those product families with different nameplate output powers, DOE scaled the efficiency 

results, per section 5.4.6.1. 

By analyzing the EPS product families DOE determined a scaling relationship between 

output voltage and efficiency for all of the representative units, except the 2.5-watt representative 

unit. DOE believes that 2.5-watt EPSs do not have a scaling relationship because these EPSs 

have very low nameplate output power such that the overhead losses are a very significant 

portion of the total losses. Thus the overhead losses obscure the changes in power consumption 

losses that vary with output voltage, so no scaling with output voltage is necessary. 

For the remaining three representative units, DOE developed a low-efficiency curve and 

a high-efficiency curve to characterize the lower-efficiency and higher-efficiency product 

families. The following discussion illustrates how DOE developed a low-efficiency and highefficiency curve for the 60-watt representative unit. The same methodology applies to both the 

18-watt and 120-watt representative units. 

To perform output voltage scaling for 60-watt EPSs, DOE analyzed six manufacturer 

product families, as shown in Figure 5.18. 

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80%

82%

84%

86%

88%

90%

92%

0 10 20 30 40 50 60 Efficiency [%]

Output Voltage [V]

Mfr F

Mfr D

Mfr B

Mfr G

Mfr C

Mfr H

High

Low

80%

82%

84%

86%

88%

90%

92%

0 10 20 30 40 50 60 Efficiency [%]

Output Voltage [V]

Mfr B

High

Log. (Mfr 

B)

Figure 5.18 60-Watt EPS Product Families for Output Voltage Scaling 

DOE identified Manufacturer B’s product family as having the highest efficiencies, and 

thus used its data points to create a best fit logarithmic curve to represent the higher bound for 

efficiency. Figure 5.19 presents Manufacturer B’s family product data points and the higher 

bound best fit logarithmic curve. 

Figure 5.19 High-Efficiency Curve Used for Output Voltage Scaling 

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F1 F2 F3

F4

H 1

H 2

H 3

H 4

80%

81%

82%

83%

84%

85%

86%

87%

88%

89%

0 10 20 30 40 50 60 Efficiency [%]

Output Voltage [V]

Mfr F

Mfr H

Low

To create the lower bound for efficiency, DOE considered using Manufacturer D’s 

product family. However, DOE rejected Manufacturer D’s product family because it would 

cause the low-efficiency curve to be too close to the high-efficiency curve, which would limit the 

effectiveness of the scaling relationship. Instead, DOE used a combination of Manufacturer F 

and Manufacturer H’s product families as shown in Figure 5.20. DOE rejected Manufacturer F’s 

first two points because they do not form a consistent trend with the rest of the family. DOE 

rejected Manufacturer H’s first point because its efficiency (84.1%) is below the EISA level. 

DOE did not include in its analysis any data points that did not meet EISA standards. 

Figure 5.20 Product Families Used to Create Low-Efficiency Curve for Output Voltage 

Scaling 

DOE created a best-fit logarithmic curve to represent the lower bound for efficiency 

using Manufacturer H’s second data point and Manufacturer F’s third and fourth data point, 

shown in Figure 5.21. 

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82%

83%

84%

85%

86%

87%

88%

89%

0 10 20 30 40 50 60 Efficiency [%]

Output Voltage [V]

Mfr F

Mfr H

Low

y = 0.0308ln(x) + 0.7918

R2 = 0.8746

y = 0.0203ln(x) + 0.7979

R2 = 0.895

0.82

0.83

0.84

0.85

0.86

0.87

0.88

0.89

0.9

0.91

0.92

0 10 20 30 40 50 60 Efficiency [%]

Output Voltage [V]

High

Low

Log. 

(High)

Figure 5.21 Low-Efficiency Curve Used for Output Voltage Scaling 

In summary, Figure 5.22 presents the data points used to create the best fit curves, as 

well the upper and lower bounds for efficiency. 

Figure 5.22 High-Efficiency and Low-Efficiency Curves for Output Voltage Scaling 

Table 5.20 presents the equations for the low-efficiency curves and a high-efficiency 

curves relating efficiency (Eff) to nameplate output voltage (Vout) for each representative unit. 

The results for the four representative units are shown in Figure 5.23, Figure 5.24, Figure 5.25, 

and Figure 5.26. Where voltage scaling was necessary, DOE scaled test unit and manufacturer 

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60%

62%

64%

66%

68%

70%

72%

74%

0 2 4 6 8 10 12 14 Efficiency [%]

Output Voltage [V]

Mfr B (scaled 3W)

Mfr B (scaled 2W)

data relative using these equations for output voltage in the same manner it used the EISA 2007 

and ENERGY STAR 2.0 equations for output power, discussed in section 5.4.6.1. As noted in 

the executive summary, DOE is seeking stakeholder comment on its voltage scaling procedure. 

Table 5.20 Curves Characterizing the Relationship between Output Voltage and Efficiency 

Representative Low-Efficiency Curve High-Efficiency Curve Unit 

18 W Eff = 0.0371 * ln(Vout) + 0.6997 Eff = 0.0143 * ln(Vout) + 0.8092 

60 W Eff = 0.0203 * ln(Vout) + 0.7979 Eff = 0.0308 * ln(Vout) + 0.7918 

120 W Eff = 0.0203 * ln(Vout) + 0.8086 Eff = 0.0248 * ln(Vout) + 0.8061 

Figure 5.23 2.5-Watt EPS Product Families for Output Voltage Scaling 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

74%

76%

78%

80%

82%

84%

86%

88%

0 10 20 30 40 50 60 Efficiency [%]

Output Voltage [V]

Mfr A

Mfr B

Mfr C

Mfr D

Mfr E

High

Low

Log. 

(High)

Log. 

(Low)

80%

82%

84%

86%

88%

90%

92%

0 10 20 30 40 50 60 Efficiency [%]

Output Voltage [V]

Mfr F

Mfr D

Mfr B

Mfr G

Mfr C

Mfr H

High

Low

Log. 

(High)

Log. 

(Low)

Figure 5.24 18-Watt EPS Product Families for Output Voltage Scaling 

Figure 5.25 60-Watt EPS Product Families for Output Voltage Scaling 

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78%

80%

82%

84%

86%

88%

90%

92%

0 10 20 30 40 50 60 Efficiency [%]

Output Voltage [V]

Mfr B

Mfr A

Mfr D

Mfr I

Mfr H

Mfr J

High

Low

Log. 

(High)

Log. 

(Low)

Figure 5.26 120-Watt EPS Product Families for Output Voltage Scaling 

An example of an instance where output voltage scaling was necessary was with unit 

#999 which had a nameplate output power of 56W and voltage of 16V. Unit #999 was used as 

the 60W CSL0 representative unit (see Table 5.17). Since this unit had a nameplate output 

voltage of 16V, it was necessary to scale it to that of an equivalent 15V unit. The original, tested 

efficiency of unit #999 was 86.0%, which was first scaled using output cord (see Section 5.4.6.3 

for details) and output power scaling (output power scaling has no effect between 56W and 

60W— see Section 5.4.6.1 for details) to 85.5%. Then, after applying the output voltage 

scaling, the efficiency was scaled from 85.5% to 85.4%. 

5.4.6.3 Scaling Efficiency with Output Cord 

The output cord of an EPS can have an appreciable impact on its measured efficiency due 

to resistive losses in the conductors. Based on test unit data, the output cord, which was 

determined to be of length 1.66m, can cause an efficiency drop of up to 1.97 percentage points 

versus units with no cord. Table 5.21 below shows the average and maximum efficiency drops 

between a unit with no output cord and a unit with a 1.66m cord, for each of the representative 

units: 

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Table 5.21 Effects of a 1.66m Output Cord on EPS Efficiency in Percentage Points 

Representative Unit 

Average Efficiency 

Drop 

[Percentage Points] 

Maximum Efficiency 

Drop 

[Percentage Points] 

2.5W 

18W 

60W 

120W 

0.59% 

0.63% 

0.82% 

0.84% 

0.73% 

0.98% 

1.16% 

1.97% 

DOE considered the effect of the output cord significant in creating CSLs for the Class A 

EPSs engineering analysis, based on the fact that merely a few percentage points separate the 

most and least efficient units on the market at a given output power level. Additionally, 

differences in cord length impact consumer utility: a longer output cord, which is less efficient, 

provides additional consumer utility by increasing the reach between the EPS and the end-use 

application. Figure 5.27 shows a plot of the kinds of output cord lengths found in the units DOE 

tested. 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

Cord Lengths of Tested EPS Units 
 

0 

2 

4 

6 

8 

10 

12 

14 

16 

Number of Units 

0.910.951.101.161.181.221.451.501.521.631.691.731.761.781.801.821.841.861.881.901.921.982.03 

Cord Length (m) 

Figure 5.27 Cord Lengths of Tested EPS Units 

*Data as of March 5th, 2010. 

Since there are so many different cord lengths, DOE normalized tested efficiencies based 

on a single baseline cord length for the preliminary analysis. The 1.66m average cord length, 

was derived from the individual average cord lengths in each representative unit, as shown in the 

table below: 

Table 5.22 Average Output Cord Lengths 

Representative 

Unit 2.5W 18W 60W 120W 

Average of 

Averages 

Average Cord 

Length [m] 1.77 1.78 1.52 1.55 1.66 

*Data as of March 5th, 2010. 

To derive the output cord efficiency scaling equation, DOE used the fact that the 

electrical resistance 

R

of a wire depends on the resistivity , length , and cross sectional 

area , of the wire, in the following manner: . Therefore, an identical EPS whose 

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EERE-2008-BT-STD-0005 COMMENT 31
 

PIN PPCB PCORD POUT CORD RCORD P I

2

 

 

 

 

output cord length was hypothetically changed from length , to a baseline-length would have 

an output cord resistance of 

CORD

B

NORM R

L

L

R . 

Secondly, the power into an EPS is partially transmitted out of the output cord end and 

partially consumed in the printed circuit board and the output cord components. The third fact 

that was used is that the power loss in the output cord is equal to the square of the current times 

the resistance of the cord. The second and third equations are shown below: 

Using these three pieces of information, the output cord efficiency scaling equation was 

derived. The equation for modifying the efficiency of an EPS with a certain output cord length 

to that with a different output cord length is shown below: 

.

1

2 2 2

L

L

P I R

P

R P I R

L

L

I

P

B

IN CORD

OUT

CORD IN CORD

B

OUT

NORM

Variables Defined 

: Input power 

PIN PPCB

: Power consumed by the EPS device in the conversion process 

PCORD

: Power loss due to resistance in the cord 

POUT

: Output power 

: Output current 

: Resistance of a given cord 

: Resistance of a cord normalized for length 

: Efficiency of a given cord 

: Efficiency of a given cord, normalized for length 

: Baseline cord length, defined to be 1.66m in this analysis. 

RCORD RNORM CORD NORM LB

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As noted in the executive summary, DOE is seeking stakeholder comment on its output 

cord scaling procedure. 

One example of an instance where it was necessary to scale based on the length of the 

output cord was with unit # 999, which was chosen for the 60W CSL0 representative unit (see 

Table 5.15). Since this unit had an output cord of length 1.09m, it was necessary to scale its 

efficiency to that of a unit with a 1.66m cord. The original, tested average active-mode 

efficiency of unit #999, which was 86.0%, was therefore scaled to 85.5% using the output cord 

scaling procedure. In general, the effect could be smaller or larger depending on how far away a 

unit’s output cord is from 1.66m, and the resistance of the output cord per unit length. 

Output cord scaling was used to normalize the representative unit data points; however the CSL 

equations do not consider output cord length. As stated previously, DOE did not include output 

cord length in the CSL equations to maintain their simplicity. Instead, the CSL equations are 

developed based on the assumption that all EPS output cords are 1.66m. As noted in the 

executive summary, DOE is seeking stakeholder comment on whether to include output cord 

length in the CSL equations. 

5.4.6.4 Scaling Cost by Nameplate Output Power 

In interviews, manufacturers indicated that for products whose nameplate output power is 

close to the representative unit output power (within 10%), the cost difference is negligible, 

hence there is no need to scale cost by nameplate output power. However there were a few 

exceptions: one manufacturer provided data for a 5-watt EPS to characterize the 2.5W 

representative unit. In that case, the manufacturer indicated that costs should be divided in half, 

consistent with the difference in output power. Similarly, another manufacturer characterized the 

120-watt representative unit using a 100-watt EPS; the manufacturer indicated that the costs 

should be scaled proportionally. 

5.4.6.5 Scaling Cost by Output Cord Length 

As noted previously, DOE scaled efficiency by output cord length for test unit. 

Similarly, DOE scaled MSP by output cord length for selected test units that iSuppli tore down 

whose cord lengths were different from the representative units’ cord length of 1.66m. For the 

test units, DOE scaled the cost of the output cord in the BOM proportionally to the change in 

length. 

For the manufacturer data, some manufacturers noted that they did not account for cord 

losses in their cost-efficiency data. For those units, DOE lowered the efficiency of the units, but 

did not change their MSPs since the all MSPs were provided on a relative scale. Consequently, 

increasing all MSPs by the same amount did not affect the relative relationship between the 

costs. 

5.4.6.6 Class A EPS Markups 

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Bill of 

Materials 

(BOM)

Labor and Utilities

Manufacturer 

Production Cost 

(MPC or “Factory 

Cost”)

Original Equipment 

Manufacturer 

(OEM)

Manufacturer 

Selling Price 

(MSP)

Retail Price

Components Consumer

Integrated 

Circuit (IC)

Others

EPS Manufacturer 

“Original Device Manufacturer” (ODM)

DOE gathered inputs on markups from manufacturer interviews. Specifically, DOE 

questioned manufacturers regarding typical markups for an EPS between MPC, the cost of the 

EPS as it leaves the factory, and MSP, the price at which the EPS is sold to an OEM. DOE 

aggregated the data provided by multiple manufacturers to determine that a typical markup from 

MPC to MSP is approximately 35.5%, and a typical markup from BOM to MSP is 62.5%. DOE 

used this markup to determine MSP for selected test units as well as manufacturer data. Figure 

5.28 illustrates the markup chain from the original parts to the end-consumer. 

Figure 5.28 The Full Markup Chain, including the steps from BOM to MPC to MSP. 

5.4.7 Class A EPS Cost and Efficiency Relationships from Testing and Teardowns 

For each representative unit, DOE combined the scaled efficiency test results with the 

scaled MSP for the three EPS test units used to characterize the baseline efficiency level, CSL1, 

and CSL3. As explained in section 5.4.3.2, DOE selected test units to characterize CSL0, CSL1, 

and CSL3 such that the units’ scaled efficiencies (per section 5.4.6) were equal to or slightly 

more efficient than the CSLs detailed in section 5.4.2 and that the units’ efficiencies maintained 

the matched-pairs relationship. For each of these test units, iSuppli conducted teardowns to 

estimate MPC, as explained in section 5.4.4. DOE then scaled and marked up the test units’ 

MPC values to MSP values. 

DOE used the first eleven test units presented in Table 5.19 to characterize the CSLs for 

the four representative units. Before DOE used the data to generate cost-efficiency relationships, 

DOE normalized the data through efficiency and cost scaling steps. The scaling steps were 

applied in the order shown in Figure 5.16. Table 5.23 shows the details of which test units 

underwent which types of scaling. For details on the scaling procedures, see Section 5.4.6. For 

some of the test units that underwent scaling, some of the scaling had no effect. Specifically, 

output voltage scaling had no effect on 2.5W representative units (see Section 5.4.6.2 for 

explanation), and output power scaling had no effect on the 60W and 120W representative units 

(see Section 5.4.6.1 for explanation). Following Table 5.19, DOE presents the test and teardown 

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results in Table 5.24, Table 5.25, Table 5.26, and Table 5.27 for the 2.5W, 18W, 60W, and 

120W representative units, respectively. 

Table 5.23 Scaling and Markup Steps Performed On The Test Units 

Rep. 

Unit 

Output 

Power 

Test 

Unit 

# 

Efficienc 

y Scaling 

by 

Output 

Power 

Efficienc 

y Scaling 

by 

Output 

Voltage 

Efficienc 

y Scaling 

by Cord 

Length 

Cost 

Scaling 

by 

Output 

Power 

Cost 

Scaling 

by Cord 

Length 

Mark-Up 

to MSP 

2.5W 

876  *   

935    

996    

18W 

949   

118   

941   

60W 

999 *    

834   

838   

120W 854 *   

951 *   

―‖ Indicates that the data was scaled to the representative unit values, with effects on 

efficiency or cost.
 

―*‖ Indicates that the data was scaled to the representative unit values, although the scaling had
 

no effect.
 

Table 5.24 Cost and Efficiency Relationship for 2.5W EPS (Testing and Teardowns) 

CSL 0 CSL 1 CSL 3 CSL 4 

Test Unit Efficiency [%]: 

Test Unit No Load Power [W]: 

CSL Description: 

CSL Eff. [%], No-Load Power [W] 

MSP Difference with CSL0 [$]: 

Original Application: 

Test Unit #: 

61.4% 

0.400 

EISA 

(58.3%, 

0.500) 

$0.00 

Cordless Phones 

876 

67.9% 

0.170 

Energy Star 

2.0 

(67.9%, 0.300) 

$0.39 

Generic 

935 

73.5% 

0.100 

Best in 

Market 

(73.2%, 

0.100) 

-$0.32 

Mobile Phones 

996 

N/A 

N/A 

Max Tech 

(73.9%, 

0.062) 

N/A 

N/A 

N/A 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

Table 5.25 Cost and Efficiency Relationship for 18W EPS (Testing and Teardowns) 

CSL 0 CSL 1 CSL 3 CSL 4 

Test Unit Efficiency [%]: 

Test Unit No Load Power [W]: 

CSL Description: 

CSL Eff. [%],No-Load Power [W] 

MSP Difference with CSL0 [$]: 

Original Application: 

Test Unit #: 

78.9% 

0.330 

EISA 

(76.0%, 0.500) 

$0.00 

Generic 

949 

81.4% 

0.270 

Energy Star 2.0 

(80.3%, 0.300) 

-$0.12 

Generic 

118 

85.4% 

0.100 

Best in Market 

(85.0%, 0.100) 

-$1.10 

Generic 

941 

N/A 

N/A 

Max Tech 

(87.3%, 

0.062) 

N/A 

N/A 

N/A 

Table 5.26 Cost and Efficiency Relationship for 60W EPS (Testing and Teardowns) 

CSL 0 CSL 1 CSL 3 CSL 4 

Test Unit Efficiency [%]: 

Test Unit No Load Power [W]: 

CSL Description: 

CSL Eff. [%], No-Load Power 

[W] 

MSP Difference with CSL0 [$]: 

Original Application: 

Test Unit #: 

85.4% 

0.210 

EISA 

(85.0%, 

0.500) 

$0.00 

Notebook 

Computers 

999 

87.0% 

0.136 

Energy Star 2.0 

(87.0%, 0.500) 

$2.20 

Generic 

834 

88.0% 

0.073 

Best in 

Market 

(88.0%, 

0.210) 

$2.64 

Generic 

838 

N/A 

N/A 

Max Tech 

(91.0%, 

0.165) 

N/A 

N/A 

N/A 

Table 5.27 Cost and Efficiency Relationship for 120W EPS (Testing and Teardowns) 

CSL 0 CSL 1 CSL 3 CSL 4 

Test Unit Efficiency [%]: 

Test Unit No Load Power [W]: 

CSL Description: 

CSL Eff. [%], No-Load Power 

[W] 

MSP Difference with CSL0 [$]: 

Original Application: 

Test Unit #: 

86.5% 

0.230 

EISA 

(85.0%, 

0.500) 

$0.00 

Notebook 

Computers 

854 

88.4% 

0.210 

Energy Star 

2.0 

(87.0%, 0.500) 

-$4.53 

Notebook 

Computers 

951 

88.4% 

0.210 

Best in 

Market 

(88.0%, 

0.210) 

-$4.53 

Notebook 

Computers 

951 

N/A 

N/A 

Max Tech 

(91.0%, 

0.165) 

N/A 

N/A 

N/A 

5.4.8 Class A EPS Cost and Efficiency Relationships from Manufacturer Interviews 

For each representative unit, DOE combined the scaled efficiency test results with the 

MSP for the three EPS test units used to characterize the baseline efficiency level, CSL1, and 

CSL3. The CSL values for CSL4 came from manufacturer interviews. Table 5.29, Table 5.30, 

Table 5.31, and Table 5.32 list data for each CSL for each representative unit. 

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Similar to the test units, the manufacturer data underwent a number of the efficiency and cost 

scaling steps. The scaling steps were applied in the order shown in Figure 5.16. Table 5.28 

shows the details of which manufacturer representative units underwent which types of scaling. 

Though most of the individual manufacturer data was not scaled, Table 5.28 indicates scaling 

wherever data for at least one manufacturer was scaled. Individual manufacturer data 

characteristics cannot be revealed due to non-disclosure agreements (NDAs) with participating 

manufacturers. Thus, if the data used contained even a single manufacturer whose data required 

a certain type of scaling, Table 5.28 lists that scaling was required for the entire aggregated 

manufacturer data set. For details on the scaling procedures, see Section 5.4.6. Following Table 

5.28, DOE presents the aggregated manufacturer results in Table 5.29,Table 5.30, Table 5.31, 

and Table 5.32, for the 2.5W, 18W, 60W, and 120W representative units, respectively. 

Table 5.28 Scaling and Markup Steps Performed On The Aggregated Manufacturer Data 

Rep. 

Unit 

Output 

Power 

Efficiency 

Scaling 

by 

Output 

Power 

Efficiency 

Scaling 

by 

Output 

Voltage 

Efficiency 

Scaling 

by Cord 

Length 

Cost 

Scaling 

by 

Output 

Power 

Cost 

Scaling 

by 

Cord 

Length 

Mark 

-Up to 

MSP 

2.5W     

18W *    

60W *   

120W *     

―‖ Indicates that the data was scaled to the representative unit values, with effects on 

efficiency or cost. 

―*‖ Indicates that the data was scaled to the representative unit values, although the scaling had 

no effect. 

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EERE-2008-BT-STD-0005 COMMENT 31
Table 5.29 Cost and Efficiency Relationship for 2.5W EPS (Manufacturer Interviews) 

CSL 0 CSL 1 CSL 2 CSL 3 CSL 4 

Mfr Unit Efficiency [%]: 58.3% 67.9% 71.0% 73.5% 74.0% 

Mfr Unit No Load Power [W]: 0.500 0.300 0.130 0.100 0.053 

CSL Description: EISA Energy Star 

2.0 Intermediate Best in Market 

Max 

Tech 

CSL Eff. [%], No-Load Power [W] (58.3%, 

0.500) 

(67.9%, 

0.300) 

(70.9%, 

0.200) 

(73.2%, 

0.100) 

(73.9, 

0.062) 

MSP Difference with CSL0 [$]: $0.00 $0.04 $0.23 $0.31 $0.42 

Original Application: N/A N/A N/A N/A N/A 

Test Unit #: N/A N/A N/A 996 N/A 

Table 5.30 Cost and Efficiency Relationship for 18W EPS (Manufacturer Interviews) 

CSL 0 CSL 1 CSL2 CSL 3 CSL 4 

Mfr Unit Efficiency [%]: 76.0% 80.3% 83.0% 85.4% 87.5% 

Mfr Unit No Load Power [W]: 0.500 0.300 0.200 0.100 0.062 

CSL Description: EISA Energy Star 

2.0 Intermediate Best in Market 

Max 

Tech 

CSL Eff. [%], No-Load Power [W] (76.0%, 

0.500) 

(80.3%, 

0.300) 

(83.0%, 

0.200) 

(85.0%, 

0.100) 

(87.3%, 

0.062) 

MSP Difference with CSL0 [$]: $0.00 $0.32 $0.42 $0.79 $1.23 

Original Application: N/A N/A N/A N/A N/A 

Test Unit #: N/A N/A N/A 941 N/A 

Table 5.31 Cost and Efficiency Relationship for 60W EPS (Manufacturer Interviews) 

CSL 0 CSL 1 CSL2 CSL 3 CSL 4 

Mfr Unit Efficiency [%]: 85.0% 87.0% 87.0% 88.0% 91.0% 

Mfr Unit No Load Power [W]: 0.500 0.500 0.200 0.073 0.073 

CSL Description: EISA Energy Star Intermediate Best in Max 

2.0 Market Tech 

CSL Eff. [%], No-Load Power [W] (85.0%, (87.0%, (87.0%, (88.0%, (91.0%, 

0.500) 0.500) 0.230) 0.210) 0.165) 

MSP Difference with CSL0 [$]: $0.00 $0.24 $0.71 $1.58 $2.90 

Original Application: N/A N/A N/A N/A N/A 

Test Unit #: N/A N/A N/A 838 N/A 

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Table 5.32 Cost and Efficiency Relationship for 120W EPS (Manufacturer Interviews) 

CSL 0 CSL 1 CSL2 CSL 3 CSL 4 

Mfr Unit Efficiency [%]: 85.0% 87.0% 88.0% 88.4% 91.7% 

Mfr Unit No Load Power [W]: 0.500 0.500 0.230 0.210 0.165 

CSL Description: EISA Energy Star Intermediate Best in Max 

2.0 Market Tech 

CSL Eff. [%], No-Load Power [W] (85.0%, (87.0%, (87.0%, (88.0%, (91.0%, 

0.500) 0.500) 0.230) 0.210) 0.165) 

MSP Difference with CSL0 [$]: $0.00 $0.66 $1.23 $1.41 $5.03 

Original Application: N/A N/A N/A N/A N/A 

Test Unit #: N/A N/A N/A 951 N/A 

5.4.9 Summary of Results for Class A EPSs 

Sections 5.4.7and 5.4.8 present engineering analysis cost-efficiency results that DOE 

derived from test and teardown results as well as manufacturer interviews, respectively. Figure 

5.29, Figure 5.30, Figure 5.31, Figure 5.32, Figure 5.33, Figure 5.34, Figure 5.35, and Figure 

5.36 present results from both of these methods in terms of MSP difference versus average 

efficiency and MSP difference versus no-load power consumption for each representative unit. 

The label ―MSP Difference‖ in these figures refers to the MSP above the baseline CSL0, as 

opposed to the absolute MSP that a consumer would pay for the product. These graphs describe 

the cost-efficiency relationship for EPSs, under the assumption that all other factors are held 

constant. To that end, DOE normalized all representative unit data to the representative unit 

criteria listed in Table 5.3. 

In summary, for each representative unit, the manufacturer data for cost versus efficiency 

and cost versus no-load power data showed a trend of increasing MSPs with higher CSLs, 

meaning that it costs more to manufacture more efficient EPSs. DOE’s SMEs agreed that, all 

other factors being held constant, the cost-efficiency curves should be upwards sloping, whereby 

more efficient EPSs correspond to higher MSPs. On the other hand, the testing and teardown 

curves’ cost-efficiency relationship was inconclusive. In many cases for the test and teardown 

curves, the CSL3 best-in-market unit was the cheapest, and the CSL0 unit was the most 

expensive. Note that the testing and teardown results are presented only for CSL0, CSL1, and 

CSL3 (CSL4 had no test unit to characterize it because it was the max-tech level, and CSL2 was 

an intermediate level that was chosen after the testing and teardown analysis was complete). 

For three of the four test and teardown representative units, the costs decreased between 

CSL1 and CSL3. DOE believes that, although it rigorously normalized the test unit data, there 

may have been factors that affect cost which were not normalized. In section 5.4.6, 

manufacturers indicate that reliability is another factor that greatly impacts EPS cost and that it is 

difficult to determine an EPS’s reliability without access to its specification sheet. DOE did not 

have access to EPS specifications and therefore could not control for reliability. Hence, DOE 

believes the testing and teardown results to be inconclusive. 

Although the trend of decreasing MSPs with higher efficiencies for Class A EPSs is 

curious, DOE is aware of such instances for Non Class A EPSs. The cost-efficiency relationship 

for high-power EPSs is an example of a negative-sloped curve, presented in the NCA EPS 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

 

 

 

 

 

Notice of Proposed Determination (NOPD) that DOE published on November 3, 2010. 74 FR 

56928. DOE found that the efficiency-related materials cost of CSL0 was $115.32. The cost 

decreased from $115.32 to $33.64 from CSL0 to CLS1. Then the cost increased from $33.64 to 

$42.32 from CSL1 to CSL3. In this analysis, there is an underlying assumption that there is the 

same utility between linear EPSs that characterize CSL0 and switched-mode EPSs that 

characterize CSL1, CSL2, and CSL3. DOE did not receive any comments on the NOPD 

disputing this assumption. Table II.29 and Figure II.7 in the NOPD provide further detail on the 

cost-efficiency relationship of high-power EPSs. 74 FR 56928, 56954. 

DOE plans to evaluate only the manufacturer data in its UEC, LCC, and NIA analyses for 

Class A EPSs, as the testing and teardown data would lead to positive LCC results at CSL 3 for 

all representative units where CSL 3 is the least expensive For the NOPR, DOE intends to 

conduct another round of testing and teardowns for Class A EPSs that attempts to control for 

additional factors. In particular, DOE intends to attempt to control the data for reliability by 

selecting EPSs with similar end-use applications of similar quality. The results for the individual 

representative units follow. 

The 2.5W representative unit has manufacturer curves that are substantially different 

from the testing and teardown curves. The manufacturer curves in both Figure 5.29 and Figure 

5.30 are upwards sloping across increasing CSLs, with the greatest increase in MSP occurring 

from CSL1 to CSL2. This is not the case with the testing and teardown curves. Figure 5.29 and 

Figure 5.30 show an increase in MSPs from CSL0 to CSL1. However, the testing and teardown 

data shows a decrease in cost from CSL1 to CSL2. Thus the testing and teardown data does not 

indicate a clear trend. Therefore, DOE considers the testing and teardown data to be 

inconclusive. 

These inconclusive testing and teardown results might be due to not controlling for the 

applications among the EPSs chosen, which can have many intricate effects, as manufacturers 

suggested (see Section 5.4.5.6 for details). Specifically, as shown in Table 5.24, EPSs #876, 

#935, and #996 are from cordless phone, generic, and mobile phone applications, respectively. 

DOE expects that these applications require EPSs with different reliability specifications. 

5-58 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

$(0.40)

$(0.30)

$(0.20)

$(0.10)

$-

$0.10 

$0.20 

$0.30 

$0.40 

$0.50 

57% 67% 77%

Manufacturer Selling Price Difference [$]

Average Active-Mode Efficiency [%]

Manufacturer Interview Data

Testing and Teardown Data

Figure 5.29 2.5W MSP vs. Efficiency curves for manufacturer and testing and teardown 

data 

-$0.40

-$0.30

-$0.20

-$0.10

$0.00

$0.10

$0.20

$0.30

$0.40

$0.50

600.00 400.00 200.00 0.00

Manufacturer Selling Price DIfference [$]

N o-Load Power [mW]

Manufacturer Interview Data

Testing and Teardown Data

Figure 5.30 2.5W MSP vs. No-load power curves for manufacturer and testing and 

teardown data 

The 18W representative unit has manufacturer curves that differ greatly from the testing 

and teardown curves. The manufacturer curves in Figure 5.31 and Figure 5.32 are upwards 

sloping, with the greatest increases in MSP occurring from CSL2 to CSL3 and CSL3 to CSL4. 

The testing and teardown curves in both Figure 5.31 and Figure 5.32 are downwards sloping. 

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These downwards-sloping testing and teardown results might be due to not controlling 

for the applications among the EPSs chosen, which can have many intricate effects. Specifically, 

as shown in Table 5.25, EPSs #949, # 118, and #941 all have generic applications. Generic 

EPSs can have significant variations in their specifications, as opposed to EPSs that are designed 

for a specific product. 

-$1.50

-$1.00

-$0.50

$0.00

$0.50

$1.00

$1.50

Manufacturer Selling Price Difference [$]

75% 80% 85% 90%

Average Active-Mode Efficiency [%]

Manufacturer Interview Data

Testing and Teardown Data

Figure 5.31 18W MSP vs. Efficiency curves for manufacturer and testing and teardown 

data 

-$1.50

-$1.00

-$0.50

$0.00

$0.50

$1.00

$1.50

600 400 200 0 Manufacturer Selling Price Difference [$]

N o-Load Power [mW]

Manufacturer Interview Data

Testing and Teardown Data

Figure 5.32 18W MSP vs. No-load power curves for manufacturer and testing and 

teardown data 

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The 60W representative unit has testing and teardown curves whose slope is steeper than 

manufacturer curves between CSL0 and CSL1. The manufacturer curves in Figure 5.33 and 

Figure 5.34 have the greatest increase in MSP from CSL3 to CSL4. Even though for the 60W 

representative unit, the testing and teardown curves are upwards sloping, the mixed relationships 

in the other three representative units leads DOE to consider this testing and teardown data 

inconclusive as well. 

One reason to suspect that even the 60W testing and teardown results are inconclusive is 

that the analysis is not controlling for the applications among the EPSs chosen, which can have 

many intricate effects, as manufacturers suggested (see Section 5.4.5.6 for details). Specifically, 

as shown in Table 5.26, EPSs #999, # 834, and #838 are from notebook computer, generic, and 

generic applications, respectively. Manufacturers indicated that generic EPSs have tremendous 

variation in meeting an assortment of stringent specifications, as opposed to EPSs that are 

designed with a specific product in mind. 

The sharp rise in cost from CSL0 to CSL1 in Figure 5.34 results from manufacturers 

only improving in the efficiency metric and not the no-load power metric from CSL0 to CSL1, 

and hence the seemingly paradoxical increase in cost on the no-load power plot (Figure 5.34) is 

explained by referring to the efficiency plot (Figure 5.33), 

$0.00

$0.50

$1.00

$1.50

$2.00

$2.50

$3.00

$3.50

84% 86% 88% 90% 92%

Manufacturer Selling Price Difference [$]

Average Active-Mode Efficiency [%]

Manufacturer Interview Data

Testing and Teardown Data

Figure 5.33 60W MSP vs. Efficiency curves for manufacturer and testing and teardown 

data 

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$0.00

$0.50

$1.00

$1.50

$2.00

$2.50

$3.00

$3.50

600 400 200 0 Manufacturer Selling Price Difference [$]

N o-Load Power [mW]

Manufacturer Interview Data

Testing and Teardown Data

Figure 5.34 60W MSP vs. No-load power curves for manufacturer and testing and 

teardown data 

The 120W representative unit had manufacturer curves that looked very different from 

the testing and teardown data. The manufacturer curves in both Figure 5.35 and Figure 5.36 are 

non-decreasing across increasing CSLs, with the greatest increase in MSP occurring from CSL3 

to CSL4. The testing and teardown curves, on the other hand, show a decrease in cost from 

CSL0 to CSL1. 

These inconclusive testing and teardown results might be due to not controlling for the 

applications among the EPSs chosen, which can have many intricate effects, as manufacturers 

suggested (see Section 5.4.5.6 for details). Specifically, as shown in Table 5.27, EPSs #854, and 

# 951are both from notebook computers. Despite the same general application, manufacturers 

indicated that another aspect of controlling for applications involved controlling for the quality 

of the associated applications. For example, manufacturers indicated that not only is it necessary 

to control for notebook computers, but it is also necessary to compare EPSs of brand-names with 

applications of similar quality (i.e. low-end products to low-end products, and high-end products 

to high-end products, etc.). 

The sharp rise in cost from CSL0 to CSL1 in Figure 5.36 results from manufacturers 

only improving in the efficiency metric and not the no-load power metric from CSL0 to CSL1, 

and hence the seemingly paradoxical increase in cost on the no-load power plot (Figure 5.36) is 

explained by referring to the efficiency plot (Figure 5.35), 

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-$6.00

-$4.00

-$2.00

$0.00

$2.00

$4.00

$6.00

80% 85% 90% 95%

Manufacturer Selling Price Difference [$]

Average Active-Mode Efficiency [%]

Manufacturer Interview Data

Testing and Teardown Data

Figure 5.35 120W MSP vs. Efficiency curves for manufacturer and testing and teardown 

data 

-$6.00

-$4.00

-$2.00

$0.00

$2.00

$4.00

$6.00

600 400 200 0 Manufacturer Selling Price Difference [$]

N o-Load Power [mW]

Manufacturer Interview Data

Testing and Teardown Data

Figure 5.36 120W MSP vs. No-load power curves for manufacturer and testing and 

teardown data 

5.4.10 Creating Class A EPS CSL Equations for All Product Classes Based On the 

Representative Units 

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DOE identified and selected four representative units within the representative product 

class A1 on which to concentrate its analytical effort. DOE evaluated the representative units at 

four CSLs based on four sources: the EISA 2007 standard, the Energy Star 2.0 specification, test 

unit data, and manufacturer data. The following sections discuss how DOE scaled from 

representative unit data to the CSLs of product class A1, and how DOE scaled A1’s CSL 

equations to product classes A2, A3, and A4, which DOE did not analyze directly. 

5.4.10.1 Deriving CSL Equations for Product Class A1 From Representative Units 

In its testing, DOE gathered data about individual Class A EPS representative units. 

While these units provided insight pertaining to specific efficiency and no-load power values, 

DOE needed to create CSL equations to account for all units. To that end, DOE created four 

pairs of equations to define each CSL relating average efficiency to nameplate output power and 

no-load mode power consumption to nameplate output power as specified in 5.4.2: 

The equations for CSL0 are derived directly from the EISA standard. 

The equations for CSL1 are derived directly from the Energy Star 2.0 Specification for 

AC/DC basic voltage units. 

The equations for CSL2 were created by curve-fitting the data points used to characterize 

the Intermediate CSL, CSL2 (see section 5.4.2 for details on how the points were 

selected). 

The equations for CSL3 were created by curve-fitting best-in-market (BIM) test unit data 

points. 

The equations for CSL4 were created by curve-fitting data points from manufacturer 

interviews. 

The process of creating CSL2, CSL3 and CSL4 curves is described here in further detail. 

DOE derived CSL2 by fitting equations to the efficiency values of the four Intermediate level 

data points, at their respective output power values of 2.5W, 18W, 60W, and 120W (see 

equations in Table 5.9). For all its curve-fitting, DOE used the simplest possible equation form 

that was general enough to encompass all the CSL equations found in the EISA and Energy Star 

2.0 CSLs. This equation was of the form Y=a*ln(Pout) + b*Pout+c, for each of the nameplate 

output power segments, where Y indicates either the efficiency or no load-power requirement; 

Pout indicates the nameplate output power; and a, b, and c indicate the specific parameters 

defined in the respective CSLs. 

Since, even this general form of the equation could not pass through all points exactly, 

DOE ensured that the equations met three conditions. First, the distance to each point was 

minimized. Second, the equation did not exceed the tested efficiencies. Third, DOE further 

restricted the parameter choice in order to ensure that the CSL curves adhered to a matched pairs 

approach. This means that the CSL curves yielded both non-decreasing (usually higher) 

efficiency values and non-increasing (usually lower) no-load power values when moving from 

lower to higher CSLs, across all output power levels. For the fitted CSL2 equation the maximum 

difference between any data point and the equation was less than 0.5 percentage points. 

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The CSL2 no-load power equation was based on fitting the same equation forms on the 

same nameplate output power segments as was done for CSL1, for the four Intermediate level 

no-load power values at 2.5W, 18W, 60W, and 120W, without going below the chosen values 

(see equations in Table 5.10). Specifically, Table 5.8 shows that CSL1 no-load power equations 

had one constant value up to a nameplate output power of 50 watts, and another constant value 

above 50 watts. Likewise, DOE based the CSL2 equations for no-load power in Table 5.10 on 

the maximum no-load power among the two CSL2 lower power representative unit data points 

(2.5W and 18W) and the two CSL2 higher power representative units data points (60W and 

120W). The maximum of the lower power representative units was used for the first segment of 

nameplate output power, of up to 50 watts, and the maximum of the higher power representative 

units was used for the higher output power segment. 

The CSL3 and CSL4 efficiency and no-load power specifications were created using the 

same reasoning as CSL2. Instead of using the four Intermediate level data points, the CSL3 

curves were fit to the BIM data points at 2.5W, 18W, 60W, and 120W (see equations for average 

efficiency in Table 5.11 and no-load power in Table 5.12). Similarly, instead of using the four 

Intermediate level data points, the CSL4 curves were fit to the CSL4 data points at 2.5W, 18W, 

60W, and 120W, which were based on manufacturer interviews (see equations for average 

efficiency in Table 5.13 and no-load power in Table 5.14). 

5.4.10.2	 Deriving CSL Equations for Non-Analyzed Product Classes (A2, A3, and 

A4) 

After developing the CSLs for product class A1, DOE developed additional CSL 

equations for low voltage and AC/AC units. As noted in Section 5.4.2, Energy Star 2.0 has four 

product classes, including low voltage and AC/AC product classes, each with its own set of 

equations. DOE leveraged these existing Energy Star 2.0 equations in creating low voltage and 

AC/AC CSLs. 

For low voltage units, different CSL equations are necessary because low-voltage EPSs 

have lower efficiency, as detailed in section 5.4.6.2. DOE believes that AC/AC units require 

different CSL equations for no-load power based on Energy Star 2.0. Thus, there are four 

possible combinations of CSL equations: the A1 CSL equations for basic voltage and AC/DC 

no-load power (VBASIC and PNL_DC ), the low voltage equation for efficiency (VLOW), and the 

AC/AC equation for no-load power (PNL_AC). Table 5.33 shows the efficiency equations, and 

Table 5.34 shows the no-load power equations used for each of the four product classes. 

Table 5.33 Active-Mode Efficiency CSL Equations for Product Classes A1, A2, A3, and A4. 

Basic Voltage Low Voltage

AC/DC Eff: VBASIC Eff: VLOW

AC/AC Eff: VBASIC Eff: VLOW

A1 A2

A3 A4

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Table 5.34 No-Load Power CSL Equations for Product Classes A1, A2, A3, and A4. 

Basic Voltage Low Voltage

AC/DC No load: PNL_DC No load: PNL_DC 

AC/AC No load: PNL_AC No load: PNL_AC

A1

A3 A4

A2

The VLOW efficiency equations were created using different methods, depending on the 

CSL level. Though DOE had developed its own output voltage scaling method for scaling 

representative unit data points, it was not used for product class scaling, because it was only 

designed for the four specific representative units in product class A1 (see Section 5.4.6.2 for 

additional reasons and details). 

For CSL0, the curve is identical to the basic-voltage CSL0 curve because all units in the 

market already meet the EISA standard. For CSL1, the VLOW equation is based directly on the 

Energy Star 2.0 low-voltage equation. 

The VLOW curves for CSL2, CSL3, and CSL4 were created by using their respective 

CSL2, CSL3, and CSL4 VBASIC efficiency curves, and altering all equation parameters by the 

difference in the coefficients between the CSL1 VBASIC and VLOW equations. This had the effect 

of shifting the CSL2, CSL3, and CSL3 VLOW curves downwards from their corresponding VBASIC 

CSL2, CSL3, and CSL4 curves, by a similar amount as the shift between the CSL1 VBASIC and 

VLOW curves. The VLOW CSLs are shown the Table 5.35. 

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Table 5.35 The Low-Voltage Product Classes’ (A2, A4) Active Mode Efficiency Equations 

CSL Nameplate Output Power (Pno) Minimum Average Efficiency in Active Mode 

(expressed as a decimal) 

CSL 0 Identical to Basic Voltage CSL 0 Identical to Basic Voltage CSL 0 

CSL 1 

0 to ≤ 1 watt ≥ 0.497 × Pout + 0.067 

> 1 to ≤ 49 watts ≥ 0.075 × ln (Pout) + 0.561 

> 49 watts ≥ 0.860 

CSL 2 

0 to ≤ 1 watt ≥ 0.507 × Pout + 0.077 

> 1 to ≤ 49 watts ≥ 0.0825 × ln (Pout) - 0.0011 × Pout + 0.586 

> 49 watts ≥ 0.860 

CSL 3 

0 to ≤ 1 watt ≥ 0.517 × Pout + 0.087 

> 1 to ≤ 49 watts ≥ 0.0834 × ln (Pout) - 0.0014 × Pout + 0.609 

> 49 watts ≥ 0.870 

CSL 4 

0 to ≤ 1 watt ≥ 0.537 × Pout + 0.097 

> 1 to ≤ 49 watts ≥ 0.0914 × ln (Pout) - 0.0014 × Pout + 0.609 

> 49 watts ≥ 0.900 

The equation for CSL0 PNL_AC is derived directly from the EISA standard, since all 

EPSs meet this level. The equation for CSL1 PNL_AC is derived directly from the corresponding 

Energy Star 2.0 Specification for AC/AC units. To create AC PNL curves for CSL2, CSL3, and 

CSL4, DOE used the same approach as was adopted in the CSL0 and CSL1 PNL_AC curves, in 

which a constant no-load power limit was set for both the CSL0 and CSL1 PNL_AC curves. 

Specifically, the PNL_AC equations were derived by adjusting the corresponding PNL_DC curve 

such that the AC PNL curve was constant across output power, by taking the highest of the 

maximum allowable no-load power values across all nameplate output powers for the PNL_DC 

curve. The PNL_AC CSLs are shown in Table 5.36. 

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Table 5.36 AC/AC Product Classes’ (A3, A4) Maximum Allowable No-Load Power 

Equations 

CSL Nameplate Output Power (Pno) Maximum Power in No-Load 

Ac-Ac EPS 

CSL 0 0 to ≤ 250watt ≤ 0.500 watts 

CSL 1 0 to ≤ 250watt ≤ 0.500 watts 

CSL 2 0 to ≤ 250watt ≤ 0.230 watts 

CSL 3 0 to ≤ 250watt ≤ 0.210 watts 

CSL 4 0 to ≤ 250watt ≤ 0.165 watts 

5.5 NON-CLASS A EXTERNAL POWER SUPPLY ENGINEERING ANALYSIS 

In this section DOE discusses how it intends to develop the NCA EPS engineering 

analysis for the NOPR stage of the BCEPS rulemaking. First DOE describes which NCA EPS 

representative product classes and representative units it will analyze. Next DOE discusses how 

it will create CSLs for each type of NCA EPS. Then DOE explains why it believes that some of 

the cost-efficiency analysis preformed for the Class A EPSs applies to some NCA EPSs. Finally, 

DOE describes how it will apply to the NOPR the NCA EPS determination analysis that it 

published on 14 May 2010. 75 FR 27170. 

DOE based the NCA EPS engineering analysis on the analysis from the NCA EPS 

determination analysis as well as the analysis developed in this preliminary analysis for Class A 

EPSs. DOE based the analysis for multiple-voltage and high-power EPSs on the analysis 

presented in the determination analysis because DOE believes the analysis to still be valid, in 

part because interested parties did not question its validity. DOE based the analysis for medical 

and MADB EPSs on the analysis presented in the preliminary analysis for Class A EPSs because 

DOE believes there to be no technical limitations for medical and MADB EPSs to achieve the 

same efficiencies at the same costs as Class A EPSs. Further, DOE presented this concept in the 

determination analysis and interested parties did not question its validity, so long as MADB 

EPSs do not include charge control. 

5.5.1 Non-Class A EPS Representative Product Classes and Representative Units 

In this section DOE presents its selection of NCA EPS representative product classes and 

representative units based on the NCA EPS product classes presented in chapter 3. As noted 

previously, DOE based the NCA EPS product classes on the product classes from the NCA EPS 

determination analysis as well as the product classes developed in this preliminary analysis for 

Class A EPSs. 

5.5.1.1 Representative Product Classes and Units for Multiple-Voltage EPSs 

DOE chose to treat both multiple-voltage EPS product classes as representative because 

there are significant differences between the two classes as shown in Table 5.37. As explained in 

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detail in the determination analysis, representative product class X1 consists mainly of EPSs for 

imaging equipment. These multiple-voltage EPS have similar nameplate output power ratings 

for each output voltage. In contrast, EPSs in product class X2 are for video game applications 

and typically have one output that provides the majority of the output power. Since a single 

application constitutes the majority of shipments in each representative product class, DOE 

elected to use those applications as representative units as shown in Table 5.38. 

Table 5.37 Multiple Voltage EPS Representative Product Classes 

Nameplate Output Power Product Class 

< 100 watts 

≥ 100 watts 

X1 (representative 

X2 (representative) 

Table 5.38 Multiple-Voltage EPS Representative Units 

Nameplate Output 

Power [W] 

Nameplate Output 

Voltage [V] 

Second Nameplate 

Output Voltage [V] 

Example Application 

40 

203 

16 

5 

32 

12 

Multi-Function Device 

Video Game 

5.5.1.2 Representative Product Classes and Units for High-Power EPSs 

DOE chose to treat the high-power EPS product classes as representative because it is the 

only product class (shown in Table 5.39). As explained in detail in the determination analysis, 

representative product class H1 consists mainly of EPSs for ham radios. Since a single 

application constitutes the majority of shipments in the representative product class, DOE elected 

to use that application to define the attributes of the representative unit shown in Table 5.40. 

Table 5.39 High Power EPS Representative Product Classes 

Nameplate Output Power Product Class 

> 250 watts H1 (representative) 

Table 5.40 High-Power EPS Representative Units 

Nameplate Output Power [W] Nameplate Output Voltage [V] Example Application 

345 13.8 Amateur Radio 

5.5.1.3 Representative Product Classes and Units for Medical EPSs 

DOE chose to treat only medical EPS product class M1 as representative because there 

are significant similarities between the product classes shown in Table 5.41. Specifically, the 

medical EPS product classes have the same product class structure as the Class A EPS product 

classes, as explained in chapter 3. To that end, DOE applied the same structure for the medical 

EPS representative product classes and representative units (shown in Table 5.42). 

DOE took this approach because it is consistent with the approach for medical EPSs in 

the determination analysis. Specifically, in the determination analysis DOE created 

representative product classes and units for medical EPSs based on Class A EPSs. Interested 

parties did not question the validity of this approach in the determination analysis. Since 

publishing the determination analysis DOE further developed its understanding of Class A EPSs. 

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Consequently, the representative product classes and units presented in Table 5.41 and Table 

5.42 are consistent with the Class A EPS analysis in section 5.4. 

Table 5.41 Proposed Medical EPS Representative Product Classes 

Basic Voltage Output Low Voltage Output* 

AC-DC Conversion 

AC-AC Conversion 

M1 (representative) 

M3 (scaled) 

M2 (scaled) 

M4 (scaled) 

* Low voltage output EPSs have nameplate output voltage less than six volts and nameplate output current greater 

than or equal to 550 milliamps. All other EPSs are basic voltage output. 

Table 5.42 Possible Medical EPS Representative Units 

Representative 

Unit 

Nameplate Output 

Power 

[watts] 

Nameplate Output 

Voltage 

[volts] 

Example 

Application 

1 

2 

3 

4 

2.5 

18 

60 

120 

5 

12 

15 

19 

Blood Pressure Monitor 

Medical Nebulizer 

Sleep Apnea Machine 

Portable Oxygen Concentrator 

5.5.1.4 Representative Product Classes and Units for MADB EPSs 

DOE chose to treat only MADB EPS product class B1 as representative because there are 

significant similarities between the product classes as shown in Table 5.43. Specifically, the 

MADB EPS product classes have the same product class structure as the Class A EPS product 

classes, as explained in chapter 3. To that end, DOE applied the same structure for the MADB 

EPS representative product classes and representative units (shown in Table 5.44). Since DOE 

can apply all Class A EPS analysis to MADB EPSs it intends to include a 120-watt 

representative unit. However, Table 5.44 reflects that DOE has not identified an associated 

application for this unit. As noted in the executive summary, DOE is seeking stakeholder 

comment on any applications that use a 120-watt MADB EPS and whether to analyze this unit if 

it cannot identify any associated applications. 

DOE took this approach because it is consistent with the approach for MADB EPSs in 

the determination analysis. Specifically, in the determination analysis DOE created 

representative product classes and units for MADB EPSs based on Class A EPSs. Interested 

parties did not question the validity of this approach in the determination analysis. Since 

publishing the determination analysis DOE further developed its understanding of Class A EPSs. 

Consequently, the representative product classes and units presented in Table 5.43 and Table 

5.44 are consistent with the Class A EPS analysis in section 5.4. 

Table 5.43 Proposed MADB EPS Representative Product Classes 

Basic Voltage Output Low Voltage Output* 

AC-DC Conversion 

AC-AC Conversion 

B1 (representative) 

B3 (scaled) 

B2 (scaled) 

B4 (scaled) 

* Low voltage output EPSs have nameplate output voltage less than six volts and nameplate output current greater 

than or equal to 550 milliamps. All other EPSs are basic voltage output. 

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Table 5.44 Possible MADB EPS Representative Units 

Representative 

Unit 

Nameplate Output Power 

[watts] 

Nameplate Output Voltage 

[volts] 

Example 

Application 

1 

2 

3 

4 

2.5 

18 

60 

120 

5 

12 

15 

19 

RC Toy 

DIY Power Tool 

Motorized Bicycle 

[none identified] 

5.5.2 Non-Class A EPS Candidate Standard Levels of Efficiency 

In this section DOE presents its selection of CSLs for NCA EPS and how it will develop 

the CSL equations in the NOPR. DOE based the CSLs on the CSLs from the determination 

analysis as well as CSLs developed in this preliminary analysis for Class A EPSs. 

5.5.2.1 Candidate Standard Levels of Efficiency for Multiple-Voltage EPSs 

DOE developed CSLs for multiple-voltage EPSs based on those presented in the NCA 

EPS determination analysis. Specifically, multiple-voltage EPSs are distinct from other types of 

EPSs both in that their underlying technology is different as well as that there are not established 

standard levels in their market. Consequently, DOE structured the CSLs for multiple-voltage 

EPSs based on products available in the market and the theoretical maximum technologically 

feasible level described by manufacturers as shown in Table 5.45. 

Table 5.45 Multiple-Voltage EPS Candidate Standard Levels of Efficiency 

Number Reference Basis 

CSL0 

CSL1 

CSL2 

CSL3 

Market Bottom 

Mid Market 

Best in Market 

Max Tech 

Least efficient units in the market 

Efficiency in the middle of the market 

Curve fit to most efficient test unit data points 

Curve fit to manufacturer max tech data points 

In the determination analysis DOE defined the efficiency values for each CSL based on 

test data and manufacturer data. For the NOPR, DOE intends to gather more data for multiplevoltage EPSs with which to develop specific efficiency values for each CSL. In contrast to Class 

A EPSs whose minimum average efficiency and maximum no-load power consumption 

requirements are functions of nameplate output power, DOE intends to have a single efficiency 

metric for each CSL. DOE believes this approach is appropriate because although product 

classes X1 and X2 span a range of nameplate output powers, each product class has only one 

significant application and therefore only needs one value. 

5.5.2.2 Candidate Standard Levels of Efficiency for High-Power EPSs 

DOE developed CSLs for high-power EPSs based on those presented in the NCA EPS 

determination analysis. Specifically, high-power EPSs are distinct from other types of EPSs both 

in that their underlying technology is different as well as that there are not established standard 

levels in their market. Consequently, DOE structured the CSLs for high-power EPSs based on 

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products available in the market and the theoretical maximum technologically feasible level 

described by manufacturers as shown in Table 5.46. 

Table 5.46 High-Power EPS Candidate Standard Levels of Efficiency 

Number Reference Basis 

CSL0 

CSL1 

CSL2 

CSL3 

Market Bottom 

Mid Market 

Best in Market 

Max Tech 

Least efficient units in the market 

Efficiency in the middle of the market 

Curve fit to most efficient test unit data points 

Curve fit to manufacturer max tech data points 

In the determination analysis DOE defined the efficiency values for each CSL based on 

test data and manufacturer data. For the NOPR, DOE intends to gather more data for high-power 

EPSs with which to develop specific efficiency values for each CSL. In contrast to Class A 

EPSs whose minimum average efficiency and maximum no-load power consumption 

requirements are functions of nameplate output power, DOE intends to have a single efficiency 

metric for each CSL. DOE believes this approach is appropriate because although product class 

H1 spans a range of nameplate output powers, it has only one significant application and 

therefore only needs one value. 

5.5.2.3 Candidate Standard Levels of Efficiency for Medical EPSs 

DOE developed CSLs for medical EPSs based on the CSLs for product class A1 for 

Class A EPSs presented in section 5.4.2. Specifically, medical EPSs are similar to Class A EPSs 

both in that their underlying technology is similar as well as that there are established standard 

levels that can be applied to their market. However there are two differences between medical 

EPSs and Class A EPSs, one of which affected DOE’s choice of CSLs. First, medical EPSs are 

exempt from EISA regulations so DOE expects that there are medical EPSs less efficient than 

EISA standards. Second, as noted in chapter 3, medical EPSs conform to additional safety 

requirements. These requirements make the absolute price of medical EPSs higher than Class A 

EPSs, but do not affect medical EPS efficiency or incremental cost. Consequently, DOE 

structured the CSLs for medical EPSs based on the Class A EPS CSLs and set the baseline CSL0 

to the least efficient medical EPS units in the market as shown in Table 5.47 All other CSL 

equations come directly from the Class A EPS analysis. For example, the previous baseline 

CSL0 for Class A EPSs is CSL1 for medical EPSs. 

Table 5.47 Medical EPS Candidate Standard Levels of Efficiency 

Number Reference Basis 

CSL0 

CSL1 

CSL2 

CSL3 

CSL4 

Market Bottom 

EISA 2007 

Energy Star 2.0 

Best in Market 

Max Tech 

Least efficient units in the market 

EISA 2007 equations for efficiency and no-load power 

Energy Star 2.0 equations for efficiency and no-load power 

Curve fit to most efficient test unit data points 

Curve fit to manufacturer max tech data points 

In the determination analysis DOE defined the efficiency values for each CSL based on 

existing levels in the market, test data and manufacturer data. For the NOPR, DOE is 

considering gathering more data for medical EPSs with which to develop specific efficiency 

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values the baseline CSL0. This would allow DOE to characterize the benefits of higher standards 

to consumers purchasing EPSs with efficiencies below EISA requirements. However, DOE 

believes that those consumers constitute a small and shrinking part of the market, based on 

manufacturer interviews. Therefore, DOE is also considering accounting for the lowest part of 

the market in the ―EISA qualified‖ CSL as a simplifying alternative. Under this alternate 

approach, there would be no difference between Class A EPSs and medical EPSs in the 

engineering analysis. As noted in the executive summary, DOE is seeking stakeholder comment 

on which approach to pursue. 

Regardless of how DOE treats EPSs with efficiency below EISA, DOE intends to apply 

data from Class A EPSs directly to medical EPSs for those CSLs that are common between the 

two products. For each CSL, DOE intends to have equations that are functions of nameplate 

output power similar to Class A EPSs. In particular, DOE intends to apply the Class A EPS 

equations directly to the corresponding medical EPS CSLs. In addition, to scale medical EPS 

CSL equations from product class M1 to the other product classes DOE intends to use the Class 

A EPS methodology and results. DOE believes this approach is appropriate because of the 

similarity between medical EPSs and Class A EPSs. 

5.5.2.4 Candidate Standard Levels of Efficiency for MADB EPSs 

DOE developed CSLs for MADB EPSs based on the CSLs for product class A1 for Class 

A EPSs presented in section 5.4.2. Specifically, MADB EPSs are similar to Class A EPSs both in 

that their underlying technology is similar as well as that there are established standard levels 

that can be applied to their market. However there is one difference between MADB EPSs and 

Class A EPSs, which affected DOE’s choice of CSLs. Namely, MADB EPSs are exempt from 

EISA regulations so DOE expects that there are medical EPSs less efficient than EISA standards. 

In contrast to medical EPSs, DOE believes that MADB EPSs do not conform to additional 

requirements, safety or otherwise. Consequently, DOE structured the CSLs for MADB EPSs 

based on the Class A EPS CSLs and set the baseline CSL0 to the least efficient MADB EPS 

units in the market as shown in Table 5.48. All other CSL equations come directly from the 

Class A EPS analysis. For example, the previous baseline CSL0 for Class A EPSs is CSL1 for 

MADB EPSs. 

Table 5.48 MADB EPS Candidate Standard Levels of Efficiency 

Number Reference Basis 

CSL0 

CSL1 

CSL2 

CSL3 

CSL4 

Market Bottom 

EISA 2007 

Energy Star 2.0 

Best in Market 

Max Tech 

Least efficient units in the market 

EISA 2007 equations for efficiency and no-load power 

Energy Star 2.0 equations for efficiency and no-load power 

Curve fit to most efficient test unit data points 

Curve fit to manufacturer max tech data points 

In the determination analysis DOE defined the efficiency values for each CSL based on 

existing levels in the market, test data and manufacturer data. For the NOPR, DOE is 

considering gathering more data for MADB EPSs with which to develop specific efficiency 

values the baseline CSL0. This would allow DOE to characterize the benefits of higher standards 

to consumers purchasing EPSs with efficiencies below EISA requirements. However, DOE 

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believes that those consumers constitute a small and shrinking part of the market, based on 

manufacturer interviews. Therefore, DOE is also considering accounting for the lowest part of 

the market in the ―EISA qualified‖ CSL as a simplifying alternative. Under this alternate 

approach, there would be no difference between Class A EPSs and MADB EPSs in the 

engineering analysis. As noted in the executive summary, DOE is seeking stakeholder comment 

on which approach to pursue. 

Regardless of how DOE treats EPSs with efficiency below EISA, DOE intends to apply 

data from Class A EPSs directly to MADB EPSs for those CSLs that are common between the 

two products. For each CSL, DOE intends to have equations that are functions of nameplate 

output power similar to Class A EPSs. In particular, DOE intends to apply the Class A EPS 

equations directly to the corresponding MADB EPS CSLs. In addition, to scale MADB EPS 

CSL equations from product class M1 to the other product classes DOE intends to use the Class 

A EPS methodology and results. DOE believes this approach is appropriate because of the 

similarity between MADB EPSs and Class A EPSs. 

5.5.3 Developing Cost-Efficiency Results for NCA EPSs 

In this section DOE presents its methodology to develop cost-efficiency curves for NCA 

EPSs. DOE intends to develop cost-efficiency curves based the data used to generate costefficiency curves in the determination analysis as well as the data used to generate costefficiency curves for Class A EPSs in this preliminary analysis. 

To develop the NOPR, DOE intends to use the same scaling and analysis techniques for 

both Class A EPSs and non-Class A EPSs. Thus, DOE intends to revise the data from the NCA 

EPS determination analysis for the NOPR. Specifically, in developing the Class A EPS 

engineering analysis in this preliminary analysis, DOE refined the scaling methodologies it used 

in the NCA EPS engineering analysis in the determination analysis. In addition, DOE evaluated 

EPSs based on the full costs of all materials, as opposed to the determination analysis that 

evaluated EPSs based on the efficiency-related materials cost. DOE believes that its refined 

scaling methods have enhanced robustness and that the full cost of an EPS is a more appropriate 

basis for evaluation because of the inter-relatedness of EPS components. In the following 

subsections DOE explains how it will use data from the determination analysis; in all cases, DOE 

would apply the updated scaling and analysis techniques to the data. 

5.5.3.1 Cost-Efficiency Curves for Multiple-Voltage EPSs 

In the determination analysis DOE developed cost-efficiency curves for multiple-voltage 

EPSs based on testing and tearing down EPSs as well as interviewing manufacturers; DOE 

intends to follow a similar approach in the NOPR. Specifically, DOE believes that the costefficiency curves for multiple-voltage EPSs that it presented are accurate since it did not receive 

comment from interested parties indicating otherwise. Therefore, DOE intends to use that data 

(with updated scaling and analysis techniques) to develop the cost-efficiency curves in the 

NOPR for product classes X1 and X2. 

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5.5.3.2 Cost-Efficiency Curves for High-Power EPSs 

In the determination analysis DOE developed cost-efficiency curves for high-power EPSs 

based on testing and tearing down EPSs as well as interviewing manufacturers; DOE intends to 

follow a similar approach in the NOPR. Specifically, DOE believes that the cost-efficiency 

curves for high-power EPSs that it presented are accurate since it did not receive comment from 

interested parties indicating otherwise. Therefore, DOE intends to use that data (with updated 

scaling and analysis techniques) to develop the cost-efficiency curves in the NOPR for product 

class B1. 

5.5.3.3 Cost-Efficiency Curves for Medical EPSs 

To develop cost-efficiency curves for product class M1 for medical EPSs in the NOPR 

DOE intends to apply directly the cost-efficiency curves for Class A EPSs. In addition, DOE 

will conduct testing, teardowns, and manufacturer interviews to gather data on EPSs with 

efficiency less than EISA. 

5.5.3.4 Cost-Efficiency Curves for MADB EPSs 

To develop cost-efficiency curves for product class B1 for MADB EPSs in the NOPR 

DOE intends to apply directly the cost-efficiency curves for Class A EPSs. In addition, DOE 

will conduct testing, teardowns, and manufacturer interviews to gather data on EPSs with 

efficiency less than EISA. 

5.6 BATTERY CHARGER ENGINEERING ANALYSIS 

The battery charger engineering analysis estimates the cost associated with increasing the 

efficiency of a representative BC. Due to the wide variety of BCs available in the market, DOE 

analyzed only a limited number of representative product classes. These are presented in 

section 5.6.1. A general discussion of the analytical methods used with each of the representative 

product classes follows, including a discussion of the selection of representative units 

(section 5.6.2), an evaluation of efficiencies in the market and development of CSLs 

(section 5.6.3), and an evaluation of the associated costs through teardowns (section 5.6.4) and 

manufacturer interviews (section 5.6.5). Finally, section 5.6.6 describes the markups applied to 

the efficiency-related production costs to arrive at manufacturer selling prices for use in later 

analyses, while section 5.6.7 describes how results from the analysis of the representative units 

were extrapolated to the remainder of BCs within each representative product class. 

Please see sections 5.6.8 through 5.6.13 for the application of the above methods to each 

of the representative product classes, and section 5.6.14 for a discussion of extending this 

analysis to the other BC product classes not analyzed directly. 

5.6.1 BC Representative Product Classes 

As discussed in the product classes section of the market and tech assessment (chapter 3), 

DOE divided BCs into 10 product classes for the preliminary analysis based primarily on battery 

voltage (in volts) and energy (in watt-hours). DOE divided BCs into additional classes based on 

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the type of input (AC or DC, inductive versus galvanic) and the type of output (AC output for 

uninterruptible power supplies). 

Although the divisions in voltage and energy between product classes were based on 

differences in topology, i.e., the underlying design of the BC power converter, there are still 

some similarities between the product classes that allow DOE to focus its analysis on a subset of 

classes and apply the results to the remainder. 

The classes that were explicitly analyzed through testing, teardowns, and interviews with 

manufacturers are called representative product classes. These were chosen as the representative 

product classes because they collectively constitute the majority of BC shipments and national 

energy consumption. By focusing its analysis on the representative product classes, DOE can 

provide the most accurate standards analysis for the applications that have the largest impact on 

individual users (due to high energy consumption) or that have the largest impact on the nation 

(due to high shipment-weighted energy consumption). 

To select the representative product classes from among the ten product classes outlined 

in chapter 3, DOE calculated the energy consumption of the applications found in the market 

survey, factoring in typical shipments, lifetimes, operating hours, and efficiencies for BCs across 

a wide range of applications. The distribution of annual shipments by product class is presented 

in Figure 5.37 while the distribution of annual energy consumptionc is presented in Figure 5.38. 

The representative product classes are also summarized in Table 5.49. 

c Annual energy consumption and unit energy consumption are used interchangeably in this document. 

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Figure 5.37. Distribution of annual shipments by product class. 

Figure 5.38. Distribution of annual energy consumption by product class. 

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Table 5.49 Representative Product Classes 

# Product Class 

Representative Product Class 

or Scaled Product Class 

AC In, 

DC Out 

< 

100 

Wh 

Inductive 

Connection 1 Low Energy, Inductive Representative Product Class 

0-4 V 2 Low Energy, 

Low Voltage Representative Product Class 

4–10 V 3 Low Energy, 

Med. Voltage Scaled 

10–48 V 4 Low Energy, 

High Voltage Representative Product Class 

100– 

3000 

Wh 

0–24 V 5 Med. Energy, 

Low Voltage Representative Product Class 

24–48 V 6 Med. Energy, 

High Voltage Scaled 

> 3000 Wh 7 High Energy Representative Product Class 

DC In, 

DC Out 

5 V Input 8 Low Energy, 

5V DC Input Scaled 

12 V Input 9 Low Energy, 

12V DC Input Scaled 

AC In, 

AC Out 

AC Output 

from 

Battery 

10 Low Energy, 

AC Output Representative Product Class 

5.6.2 BC Representative Units 

DOE focused its engineering analysis for each BC representative product class on one 

representative unit, an idealized BC typical of those found in the product class. Because results 

from the analysis of these representative units would later be extended to additional BCs, DOE 

selected them from high-volume and/or high-energy-consumption applications, as determined by 

the market survey. Nonetheless, the analysis of these BCs is pertinent to all the applications in 

the product class under the aforementioned assumption that all BCs with the same battery 

voltage and energy provide similar utility to the user, regardless of the actual end-use product 

they work with. 

DOE evaluated the data from the market survey and, for each representative product 

class, identified the most common battery voltage and energy combinations. DOE then selected 

the representative units to correspond to the most common combinations of battery voltage and 

energy that also incorporated a wide variety of applications. By selecting representative unit 

characteristics (battery voltage and energy) common to BCs for several applications, DOE (1) 

extended the applicability of the analysis across a larger portion of BCs and (2) increased the 

variety of efficiencies used in its analysis. 

To elaborate, the primary benefit of focusing on battery voltage and energy pairings that 

were typical of popular BC products across a variety of applications was the wider applicability 

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of the resultant analysis. By treating the BC component of multiple applications as an 

interchangeable component and analyzing not only—for example—cellular telephone BCs, but 

also those for cordless telephones and digital cameras, DOE ensures that the BC representative 

unit is representative of all applications for BCs with the representative-unit battery voltage and 

energy. 

As an added benefit, evaluating BCs for multiple applications will also result in a greater 

variety of costs and efficiencies represented in the analysis. Just as the end-use product 

applications vary in cost and size, so do their BCs. Now, because these two characteristics of a 

BC impact its efficiency,d the efficiency of BCs tends to stratify by application. By analyzing 

multiple applications, DOE therefore ensures that its analysis takes into account the full variety 

of BCs efficiencies in the market. 

Figure 5.39 shows the characteristics of the BC representative units superimposed over 

the results of the market survey, previously presented in Figure 5.3 The figure illustrates how 

the representative units compare to the data obtained through the market surveys. Additional 

information regarding the representative units is compiled in Table 5.50. In addition to the 

battery energy and voltage, the table also displays typical production volumes for a single BC 

model in each product class. These volumes were used only in the teardown portion of the 

engineering analysis, where they were used to calculate how the fixed costs of manufacturing 

equipment and non-recurring engineering costs would be amortized over the total number of BCs 

in a production run, and their impact on the unit price. 

d Efficiency has a real impact on the minimum size of electronic components, as the components’ ability to dissipate 

heat is constrained by their available surface area. The smaller the component, the less surface area it has. Therefore, 

requirements on size and weight often motivate more efficient designs. 

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Table 5.50 The BC representative units for each representative product class. 

Rep. 

Unit 

# 

Product 

Class 

Battery 

Voltage 

V 

Battery 

Energy 

Wh 

Annual 

Production 

Volume 

K units 

Lifespan 

Production 

Volume 

K units 

Typical 

Applications 

1 Low Energy, 

Inductive 3.6 1.5 500 2000 Toothbrushes 

2 Low Energy, 

Low Voltage 3.6 3 480 1600 Cellular and Cordless Phones 

3 Low Energy, 

Med. Voltage Scaled Product Class 

4 Low Energy, 

High Voltage 10.8 20 640 2180 

Notebook 

Computers, 

Power Tools 

5 Med. Energy, 

Low Voltage 12 800 50 500 

Marine 

Chargers, 

Wheelchairs 

6 Med. Energy, 

High Voltage Scaled Product Class 

7 High Energy 48 3750 150 1460 Golf Carts 

8 Low Energy, 

5V DC Input Scaled Product Class 

9 

Low Energy, 

12V DC 

Input 

Scaled Product Class 

10 Low Energy, 

AC Output 12 70 1000 5000 Uninterruptible Power Supplies 

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Figure 5.39 The BC representative units superimposed over the BC market survey results. 

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5.6.3 BC Candidate Standard Levels of Efficiency 

Subsequently, DOE examined the impacts on cost of improving the efficiency of each of 

the representative units presented in section 5.6.2 to evaluate the impact and assess the viability 

of potential energy efficiency standards. As described in the technology assessment and 

screening analysis, chapters 3 and 4, the technology options for improving efficiency are many; 

each incremental technology improvement increases the BC efficiency along a continuum. The 

engineering analysis develops cost estimates for several CSLs along that continuum. 

CSLs are often based on (1) efficiencies available in the market; (2) other voluntary 

specifications or mandatory standards that cause manufacturers to develop products at particular 

efficiency levels; and (3) the maximum technologically feasible level.e 

There are no current energy conservation standards for BCs, and the ENERGY STAR 

efficiency1 level may not be widely applicable.f Therefore, DOE based the CSLs for its BC 

analysis on the efficiencies attainable through the design options presented previously, as seen in 

commercially available units. DOE selected commercially available BCs at the representativeunit battery voltage and energy from the high-volume applications identified in the market 

survey. DOE then tested these in accordance with the proposed DOE BC test procedure. For 

each representative unit, DOE then selected CSLs to correspond to the efficiency of BC models 

that were comparable to each other in most respects, but differed significantly in efficiency. 

In general, for each representative unit, DOE chose the baseline (CSL 0) unit to be the 

one with the highest annual energy consumption, and the best-in-market (CSL 2) to be one with 

the lowest. Where possible, the energy consumption of an intermediate model was selected as the 

basis for CSL 1, to provide additional resolution to the analysis.g 

Unlike the previous three CSLs, CSL 3 was not based on an evaluation of the efficiency 

of BC units in the market, since BCs with maximum technologically feasible efficiency are not 

commercially available due to their high cost. Where possible, Navigant Consulting, obtained 

manufacturer estimates of max-tech costs and efficiencies. In some cases manufacturers were 

unable to offer any insight into efficiencies beyond the best currently available in the market. An 

independent estimate of the efficiency of a max-tech unit was also performed by DOE through 

extrapolation from its analysis of the best-in-market (CSL 2) unit by estimating the impacts of 

adding any remaining energy efficiency design options. When neither methods was feasible, 

there is no data provided at this time for CSL 3. 

e The ―max-tech‖ level represents the most efficient design that is commercialized or has been demonstrated in a 

prototype with materials or technologies available today. ―Max-tech‖ is not constrained by economic justification, 

and typically is the most expensive design option considered in the engineering analysis. 

f The ENERGY STAR level for BCs was not adopted as a CSL because the ENERGY STAR BC guidelines are 

limited in scope mainly to BCs for motor-operated applications and furthermore do not consider energy 

consumption in active mode. 

g An alternative approach would have set CSL 1 at the best-in-market unit. The approach would have been used in 

the absence of an intermediate, improved-efficiency unit. However, DOE decided against this approach to ensure 

naming consistency. 

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The CSLs in Table 5-51 are presented in terms of annual energy consumption, with 

higher CSLs corresponding to lower energy consumption, assuming a class-average usage 

profile. However, to minimize the sensitivity of the CSL units to the particular usage profile 

selected for a given product class, DOE based its CSLs on the successive BC units that show 

efficiency improvement in all of the modes—i.e., active, maintenance, no-battery, and off 

modes. Thus, although the results of the analysis may change depending on the usage profile 

selected, the ordering of the CSLs will not. The BC model corresponding to the baseline CSL 

will continue to consume more energy than that corresponding to the next higher CSL, and so on, 

regardless of the usage profile. These CSLs are summarized for each representative unit in Table 

5-51, below, while the usage profiles used to calculate energy consumption at each CSL are 

shown in Table 5.52. 

Table 5-51. Energy Consumption of Battery Charger Representative Units at Each 

Efficiency Level 

# Efficiency Level 

Annual Energy Consumption by Representative Unit 

kWh 

1 2 4 5 7 10 

Low 

Energy, 

Inductive 

Low 

Energy, 

Low 

Voltage 

Low 

Energy, 

High 

Voltage 

Med. 

Energy, 

Low 

Voltage 

High 

Energy 

Low 

Energy, 

AC 

Output 

1.5 Wh, 

3.6 V 

3 Wh, 

3.6 V 

20 Wh, 

10.8 V 

800 Wh, 

12 V 

3750 Wh, 

48 V 

70 Wh, 

12 V 

0 

1 

2 

3 

Baseline 

Improved 

Best-in-Market 

Max-Tech* 

10.0 10.0 40.9 112.7 290.0 65.2 

7.0 5.1 10.9 78.7 250.0 19.6 

3.5 1.2 6.4 45.0 200.0 6.4 

- - - 10.0 150.0 1.5 

* For some product classes, manufacturer interviews did not yield any cost-efficiency data at the 

max-tech CSL. 

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Table 5.52 Weekly Usage Assumptions for Battery Charger Representative Units 

Representative 

Unit 

Time Per Day Spent in Each Mode 

Number 

of Full 

Charges 

Per Day 

Active 

and 

Maint. 

hr 

NoBattery 

hr 

Unplugged 

hr 

Off 

hr 

Total 

hr 

1 Low Energy, 

Inductive 23.9 0.1 0.0 0.0 24.0 0.3 

2 Low Energy, 

Low Voltage 10.0 4.9 9.1 0.0 24.0 0.6 

4 Low Energy, 

High Voltage 17.4 0.3 6.1 0.2 24.0 1.0 

5 Med Energy, 

Low Voltage 7.7 0.5 15.8 0.0 24.0 0.6 

7 High Energy 7.7 0.1 16.2 0.0 24.0 0.4 

10 Low Energy, 

AC Output 24.0 0.0 0.0 0.0 24.0 0.0 

5.6.4 BC Teardown Analysis 

As mentioned in the discussion above, the CSLs used in the BC engineering analysis 

were based on the efficiencies of BCs available in the market. Following testing, the units 

corresponding to each commercially available CSL were disassembled to (1) evaluate the 

presence of energy efficiency design options and (2) estimate the materials cost. The 

disassemblies were performed by one of DOE’s subject-matter experts and included an 

examination of the general design of the BC as well as an evaluation of the presence of any of 

the technology options discussed in chapter 3. 

After the BC units corresponding to the CSLs were evaluated, they were torn down by 

iSuppli, another DOE contractor. For most BCs, the teardowns were comparable to those 

conducted for EPSs, described in section 5.4.4. 

Teardowns were done differently for BCs embedded inside complex consumer electronic 

products such as camcorders and notebook computers. Because the BC constitutes a small 

portion of the circuitry of these products, DOE did not evaluate the entirety of the products’ cost. 

Rather, iSuppli identified the subset of components in each product enclosure responsible for 

battery charging, including the battery, charge regulator, and any related power converters and 

voltage regulators. 

In general, any component in the product and enclosure can be categorized as (1) 

intended solely for battery charging functions, such as the battery itself; (2) intended solely for 

non-battery charging functions, such as a user-interface component; and (3) intended for both 

battery charging and non-battery charging functions; such as a power supply. For the preliminary 

analysis, iSuppli included in the BC bill-of-materials components in categories 1 and 3, the latter 

because of their crucial role in the battery charging process. Nonetheless, this choice was not 

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always appropriate and cases where dual-purpose components such as microcontrollers 

unnecessarily inflated the cost of the BC are noted in the subsequent sections. 

5.6.5 BC Manufacturer Interviews 

In January, February, and March of 2010, Navigant Consulting, Inc. (Navigant 

Consulting) interviewed several battery charger (BC) manufacturers on behalf of the U.S. 

Department of Energy (DOE). Of these, some manufactured the BCs directly, while others were 

original equipment manufacturers (OEMs) of battery-operated products. The purpose was to 

obtain data on the possible efficiencies and resultant costs of consumer BCs. Navigant 

Consulting entered into non-disclosure agreements whereby it can present to DOE general 

information about the EPS market and technology, but no confidential data specific to any 

individual manufacturer. 

Prior to the interview, each manufacturer was sent a Cost-Efficiency Estimation Survey 

(included as appendix 5C) to guide responses. To ensure consistency between manufacturers, 

the survey specified the parameters of each BC representative unit under consideration, 

previously presented in section 5.6.2. 

5.6.5.1 Manufacturer Responses 

For each representative unit, the interviewers asked manufacturers to describe the 

technological improvements and associated costs necessary to meet each of the CSLs presented 

in section 5.6.3. These CSLs were also presented in a disaggregated form (i.e., energy 

consumption by mode, rather than combined into a weighted annual energy consumption) to help 

the respondents. 

Nonetheless, in many cases, manufacturers were unable to provide information in terms 

of the representative unit, and responded instead with information on other popular models with 

which they were more familiar. The output characteristics of these models are plotted in relation 

to the representative units in Figure 5.40. 

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Power 

Tools 

Notebook 

Computers 

Figure 5.40 Representative units and units described by manufacturers. 

The most significant differences between manufacturer’s units and the representative 

units can be seen in the low energy, high voltage product class (20 Wh, 10.8V). This product 

class includes notebook computers and power tools. In general, the notebooks align with the 

representative unit battery voltage, but have higher energy, while the power tools align with the 

battery energy, but have higher voltage. This is due to the competing requirements of the two 

applications: batteries for notebooks are designed for maximum energy storage, while those for 

power tools deliver maximum power. This leads to not only higher voltages in power tools, but 

also different battery design. Some manufacturers felt that units within the same product class 

can only be compared if they have the same chemistry (i.e., lithium-ion or nickel) and cell type 

(i.e., power vs. energy cells). 

Nonetheless, this will become less of a concern as products continue to shift from nickel 

to lithium-ion batteries. For existing products, manufacturers reported that despite different 

OEMs and suppliers, there is similarity in design between chargers for various applications and 

chemistries, with the same architectures and methods of operation. Furthermore, several 

manufacturers revealed that the difference in charge rate between BCs for the two applications— 

a function of the intrinsic qualities of the cells (i.e., power vs. energy) as well as the usage—is 

shrinking, with both startups and established companies offering notebooks with charge rates 

above 0.5 C (compared to 1 C for professional power tools). DOE welcomes further comment on 

any dissimilarities between BCs for these two types of low energy, high voltage products, and 

how best to address them in the analysis, e.g., through the creation of additional product classes. 

Other discrepancies between the representative units and the manufacturers’ popular units 

do not seem as significant. In general, manufacturers did not expect the energy consumption of a 

BC to vary due to small variations in battery voltage and energy—especially at the higher battery 

energies where there is a diminishing impact of fixed losses at higher output power. This same 

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effect is responsible for the flattening of the EPS efficiency curve at higher powers, discussed in 

greater depth in section 5.4.6.1. 

5.6.5.2 Aggregation of Manufacturer Responses 

After collecting information from manufacturers on the mode-specific energy 

consumption and cost of battery chargers, Navigant Consulting used the following process to 

calculate aggregate manufacturer cost-efficiency data at each CSL: 

1. Calculate the unit energy consumption for each manufacturer design; 

2. Perform a regression analysis of each manufacturer’s data using a basis function, 

resulting in a cost-efficiency curve for each manufacturer defined for every UECh

; 

3.	 Translate each manufacturer curve to obtain incremental costs from the baseline; 

4.	 Average all the manufacturers’ incremental costs at each CSL, resulting in an 

incremental aggregate cost-efficiency curve; 

5.	 Translate the aggregate curve to equal the teardown results at the baseline UEC, 

resulting in an absolute incremental cost-efficiency curve; and 

6.	 Finally, decompose the aggregated UECs at each CSL to estimate performance in 

each mode for a typical manufacturer unit (used for comparison with teardown results 

and for calculating application-specific energy consumption used in the LCC 

analysis). 

Each of these steps is described in the sections that follow. 

Calculate the UEC for Each Manufacturer-Supplied Design 

Navigant Consulting used the shipment-weighted average usage profile for each product 

class to calculate the annual energy consumption of each BC when used with the typical mix of 

applications for the product class. The derivation of the application-specific usage profiles, the 

resultant product class-average usage profiles, and the calculation of the UEC are all described in 

Chapter 7 of the TSD; nonetheless, these procedures were used within the engineering analysis 

prior to reporting manufacturer’s cost-efficiency data as a necessary step in the aggregation 

procedure. 

Regression Analysis to Calculate Manufacturer Costs Across all UECs 

However, the resulting shipment-weighted UECs did not necessarily coincide with the 

UECs specified at each CSL; therefore, it was not possible to simply average the costs provided 

by the manufacturers at each CSL to obtain an aggregate cost-efficiency curve. Instead, Navigant 

Consulting performed a regression analysis of the manufacturer cost-efficiency data, to obtain a 

best-fit cost-efficiency curve for each manufacturer. 

h Unit energy consumption (UEC) and annual energy consumption are used interchangeably in this document. 

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According to the manufacturer interviews, large improvements in energy efficiency could 

initially be made at relatively little cost. For example, manufacturers reported that improved 

transformer steel could decrease the energy consumption of low-energy, low-voltage chargers by 

20 percent for a $0.25 increase in selling price. However, further improvements would offer 

diminishing returns until the maximum-technologically achievable efficiency, beyond which no 

further improvements could be possible given currently available technology. An ideal charger 

with zero losses in active, maintenance, or no-battery modes, but with a lossy battery, could be 

assumed to have an infinite selling price. 

Navigant Consulting modeled this apparent relationship between cost and efficiency as a 

curve of the form presented in Eq. 1, below: 

x

1

a

m UEC b

MSP 1

, 

Eq. 1 

Where: 

MSP is the manufacturer’s selling price;
 

UEC is the unit energy consumption;
 

m is a parameter controlling the concavity of the curve;
 

a is a parameter corresponding to the flatness of the curve at the lower efficiencies; and
 

b is a parameter corresponding to the energy consumption of the ideal charger.
 

Curves of this form were fitted to the MSP-versus-shipment-weighted-UEC data for each 

manufacturer; the a variable, above, was adjusted as necessary to maximize the coefficient of 

determination (R2 value). This process is illustrated in Figure 5.41. 

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Figure 5.41 Illustration of the regression analysis of manufacturer cost-efficiency data. 

Translate Curves to Obtain Incremental Costs from the Baseline 

After calculating the manufacturer best-fit-curves, Navigant Consulting translated each 

one by subtracting the cost at the baseline CSL. As illustrated in Figure 5.42, the cost translation 

process shifts the absolute system costs of each manufacturer’s products so that the cost of the 

baseline system is consistent across all manufacturers. By ensuring that all manufacturers share a 

common baseline system cost, DOE was able to compare manufacturers’ data points directly 

while maintaining each manufacturer’s incremental costs as efficiency increases, allowing for a 

direct analysis of the cost of efficiency improvements regardless of baseline costs (which may 

vary depending on the size of the manufacturer). 

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Figure 5.42 Illustration of translation of curves to obtain incremental costs from the 

baseline 

Average the Incremental Costs at Each CSL 

The last step of the procedure produced cost-efficiency relationships with a common 

baseline for each manufacturer across all UECs. Next, DOE aggregated these responses by 

calculating the cost for each manufacturer at each CSL and averaging them, such that the 

baseline aggregate cost was the average of the manufacturer costs at the baseline CSL 0 (equal to 

zero from the last step), the aggregate cost at CSL 1 was the average of the manufacturer costs at 

CSL 1, and so on. This process is illustrated in Figure 5.43. 

Figure 5.43 Aggregation of translated manufacturer curves. 

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Translate Curves to Obtain Absolute Costs from Teardown Baseline 

Finally, to allow easier comparison between manufacturer and teardown results and more 

meaningful interpretation of analysis results as a portion of total unit costs, Navigant Consulting 

translated the aggregate manufacturer curves such that the manufacturers’ MSPs at baseline 

efficiency corresponded to the lowest teardown MSP. This process is illustrated in Figure 5.44. 

Figure 5.44 Translation of curves to obtain absolute costs from teardown baseline 

DOE realizes that other methods of normalizing the data are available, such as shifting 

the cost values to center the curves at a market-weighted average or lowest-cost manufacturer 

MSP, and such methods could be considered for use in further analyses. 

Decompose the aggregate UECs at each CSL to Estimate Mode-Specific Performance 

Finally, DOE decomposed the aggregate UEC at each CSL into mode-specific 

performance figures. As an illustration, a UEC of 10 kilowatt-hours per year for a given 

representative unit was decomposed into an estimated active-mode efficiency of 50 percent, 

maintenance mode power of 2 watts, and no-battery mode power of 1 watt. These mode-specific 

estimates were calculated taking into account the original manufacturer responses, which were 

also provided in terms of mode-specific performance, and were used to provide a more direct 

comparison to DOE test results and for use in the downstream LCC analysis. 

Rather than weighting the original manufacturer responses to calculate the UEC, 

followed by decomposing the aggregate UEC into mode-specific performance, Navigant 

Consulting could have also aggregated the mode-specific responses directly. However, doing so 

would have treated the performance in each mode as independent; by first calculating the UEC, 

DOE takes into account the fact that manufacturers will tend to optimize performance in one 

mode over that in another, depending on the usage of the product. 

A summary of the aggregated manufacturer responses, divided by representative unit, is 

presented in sections 5.6.8 through 5.6.13. 

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5.6.6 BC Cost Model 

DOE gathered inputs on markups for BCs from manufacturer interviews. Specifically, 

DOE questioned manufacturers regarding typical markups for a BC manufacturer, or original 

device manufacturer (ODM), between bill-of-materials (BOM) cost, i.e., what they pay for the 

BC components, and manufacturer selling price (MSP), i.e., the price at which they sell the BC 

to an original equipment manufacturer (OEM). This MSP is alternatively known as the OEM’s 

―assembly price‖ or ―factory price.‖ 

The analysis focused on the cost of BC components directly related to efficiency—i.e., 

the electronics, and excluded the packaging, cord, and cosmetic touches which may vary from 

product and depends greatly on the application, and whether or not the BC is integrated into a 

product or packaged separately. Therefore, the resultant MSP was an electronics MSP. 

In addition to ignoring packaging costs, DOE further simplified the analysis by 

standardizing how BC production and non-production markups would be calculated across the 

ODM and OEM, both of which may participate in the manufacturing of the BC. As further 

explanation, the four possible arrangements for BC production are illustrated in Figure 5.45, 

below. 

1.	 The OEM manufactures both the end-use product and all BC components 

2.	 The OEM manufactures the end-use product but purchases all BC components from an 

ODM or ODMs 

3.	 The OEM manufactures the end-use product, including any BC components embedded in 

the end-use product, while purchasing remaining BC components from an ODM or 

ODMs 

4.	 The OEM manufactures nothing; instead it purchases the end-use product and all BC 

components from an ODM or ODMs 

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Figure 5.45 The four ways that BC and end-use product manufacture can be divided 

between the BC supplier or original device manufacturer (ODM) and the original 

equipment manufacturer (OEM). 

Which of the above arrangements applies to a particular BC will influence how the 

various production and non-production markups are calculated. The behavior of the OEM can 

further influence the markup. Some OEMs indicated that they pass through the cost of the BC, 

while others claimed to mark it up according to the same schedule as the rest of the batteryoperated product. 

Rather than attempt to take into account all the manufacturing relationships revealed 

during the interviews, DOE’s preliminary analysis assumes a standard BC manufacturing 

markup, regardless of who manufactures the BC—whether it is the OEM or ODM. This markup 

is an average of those provided by manufacturers and accounts for the production and nonproduction costs, as well as profit, associated with electronics assembly. 

Although this markup, presented in Table 5.53, varies by product class, it is independent 

of application, as the same factories typically manufacture BCs for a host of different 

applications. The large variations in the markup can be explained by the nature of the product 

sold. In general, the lower-energy units are manufactured in larger numbers (see Table 5.50) and 

rely on somewhat generic EPSs for power conversion. In contrast, the higher-energy units are 

manufactured in smaller numbers, and the same manufacturer typically manufactures the power 

conversion and higher-value charge-control portions of the BC. DOE multiplied these productclass specific markups by the BOM cost to arrive at an MSP for each unit. 

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Table 5.53 Average markup applied to the BOM costs obtained both through teardowns as 

well as manufacturer interviews to obtain the MSP. 

Representative 

Product Class 

Average BC 

Manufacturer 

Markup 

1 Low Energy, 

Inductive 1.2 

2 Low Energy, 

Low Voltage 1.2 

4 Low Energy, 

High Voltage 1.5 

5 Med Energy, 

Low Voltage 2 

7 High Energy 2 

10 Low Energy, 

AC Output 1.6 

5.6.7 BC Scaling from Representative Units to Product Classes 

Following the development of engineering results for the representative units, DOE must 

extend its analysis to all BCs that were not specifically analyzed, but which would also be 

covered by the standard. This task is twofold: (1) scaling the representative unit results to BCs 

that are also in the representative product class, but which differ in battery voltage and energy; 

and (2) scaling the representative unit results to BCs in product classes not explicitly analyzed. 

Specific methodologies for scaling within each class are discussed in the section 

pertaining to that class (sections 5.6.8 through 5.6.13, below), while scaling to the remainder of 

the product classes is discussed in section 5.6.14. 

There are nonetheless several general strategies that may be applicable to all product 

classes, and could be used when no specific scaling can be developed for a particular product 

class. These are: (1) using the scaling procedures developed for EPSs; (2) using scaling 

relationships obtained through manufacturer interviews; or (3) using scaling relationships 

obtained from analyzing BC test results. The three are introduced in the subsections that follow; 

DOE seeks comment on the validity of each of these methods for calculating the energy 

consumption and costs of other BCs following the analysis of the representative units. 

5.6.7.1 Scaling Based on Procedures Developed for the EPS Analysis 

As mentioned previously in 5.4.6, DOE developed scaling relationships that estimate how 

the cost and efficiency of an EPS is likely to vary if redesigned for another output voltage and 

power. The output voltage scaling relationships were developed by analyzing the results of 

efficiency tests conducted on EPS families—groups of EPS made by the same manufacturer that 

share the same design and output power but vary in output voltage. The output power scaling 

relationships, on the other hand, are based on the established levels for EISA 2007 energy 

conservation standards and ENERGY STAR 2.0 voluntary guidelines for Class A EPSs, which 

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were developed by examining the market and noting the distribution of efficiencies at each 

output power. At output powers where the average efficiency distribution does not vary 

significantly, the standard levels are flat, and there can be assumed to be no relation between 

changes in output power and changes in achievable efficiency. The cost of an EPS was assumed 

not to vary with voltage, but in cases of varying output power, DOE scaled the costs 

proportionally with output power, as suggested by manufacturers. 

Because of similarities between the design and construction of EPS and BC power 

conversion circuits, those same relationships can be used to scale BC results. In particular, EPS 

output power would be treated as analogous to battery energy and EPS output voltage as 

analogous to battery voltage, while their impacts on EPS efficiency would translate to impacts on 

BC energy consumption in active mode. Since energy consumption in no-battery and 

maintenance modes is primarily dependent on overhead losses,i the energy consumption in these 

two modes would not be scaled, consistent with the lack of scaling in no-load mode for EPSs. 

5.6.7.2 Scaling Based on BC Manufacturer Interviews 

During the interviews manufacturers relayed several methods for scaling the energy 

consumption of a BC within a product class, and explained how certain circuit losses vary with 

battery voltage and energy. Specifically, when asked how changes in output power are likely to 

affect active-mode efficiency, some manufacturers stated that the active-mode efficiency of BCs 

will tend to increase with output power, up to a point, while one manufacturer specifically 

suggested using the curve contained in the ENERGY STAR specification for EPSs, as discussed 

above. 

Additionally, manufacturers also discussed non-active losses. Although some 

manufacturers indicated that losses in no-battery and maintenance modes are both mostly 

independent of the battery, others expected that they would vary with battery voltage. In 

particular: 

Standby or no-battery mode losses: A higher battery voltage would lead to higher BC 

output power, requiring a larger transformer with consequently higher magnetization 

losses; 

Maintenance mode losses: Overhead losses would increase as above, plus the 

maintenance power would increase due to the higher battery voltage (this power is the 

product of maintenance current and battery voltage). 

DOE could aggregate these and other manufacturer suggestions to develop general 

methods for scaling energy consumption in each of the modes. 

5.6.7.3 Scaling Based on Analysis of BC Test Results 

Finally, rather than use the above two strategies (using scaling relationships derived from 

the analysis of EPS results, or obtained from manufacturers), DOE could also develop novel 

i Except for slow, nickel-chemistry trickle chargers, which do not terminate their charge and therefore output 

significant current in maintenance mode. In that case, maintenance mode would be treated similarly to active. 

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scaling relationships using BC test results. One example of such a scaling relationship was 

presented by an interested party during the framework document public meeting and submitted 

to the rulemaking docket (Pacific Gas and Electric Company (PG&E), No. 13, pp. 7–9), and is 

illustrated in Figure 5.46 below. To scale the BC test results with battery energy using this 

approach, DOE would vary the performance of the representative unit with battery energy in 

proportion to a regression line, such as the one pictured in the figure. 

Figure 5.46 24-hour efficiciency standard proposed by PG&E, which could be used to scale 

the analysis of the representative unit to BCs with differing battery energies. 

Because PG&E only provided suggestions on the variation of energy consumption with 

battery energy, the other scaling relationships (energy consumption with regard to voltage, and 

cost with regard to battery energy) would have to be developed through additional regressions, or 

using one of the contrasting approaches discussed above. 

5.6.8 Representative Product Class 1: Low Energy, Inductive 

The low-energy, inductively charged product class includes BCs with a cradle that 

couples inductively to the end-use product enclosure. These consist of a rectifier/low-pass filter, 

the battery, and the end-use product (an electric toothbrush). This product class includes all 

inductively-coupled BCs with a battery voltage less than 4 volts and a battery energy less than 

100 watt-hours, though in actuality DOE has only found models with batteries with a voltage of 

1.2 to 3.6 volts and energy of 0.5 to 1.8 watt-hours. 

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Despite the low shipments and low per-unit energy consumption in this product class, 

DOE nonetheless decided to explicitly analyze it due to potential differences in design between 

inductively-coupled chargers and other classes of BCs. Although DOE interviewed 

manufacturers of inductively-coupled battery chargers, it was unable to perform product 

teardowns due to a limited number of products in the market. This scarcity prevented DOE from 

finding enough products with similar battery characteristics (energy and voltage) but with 

differing efficiencies that would imply differences in design and warrant product teardowns. 

5.6.8.1 Units Analyzed 

The results of DOE tests of low-energy inductive BCs are pictured in Figure 5.47. Also 

pictured are the results of tests conducted by Ecos Consulting and submitted to DOE by Pacific 

Gas & Electric. As can be seen, there is substantial disparity between the baseline, intermediate, 

and best-in-market units. In addition to the factor-of-two difference in battery energy between 

the intermediate unit at approximately 0.9 watt-hours and the best-in-market at 1.8 watt-hours, 

there is also a difference in voltage (not pictured) with batteries ranging from 1.2 to 3.6 volts. 

Selecting a common point of comparison was not possible. 

Figure 5.47 Test results for representative product class 1: Low Energy, Inductive. 

DOE therefore turned to manufacturers of these products, who provided information on 

units meeting the baseline through best-in-market CSLs for this product class. The estimated 

performance characteristics of a representative unit based on an aggregate of the manufacturer 

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data is presented in Table 5.54, while the design options required to reach these levels of 

performance are described in sections 5.6.8.2 through 5.6.8.4. 

Table 5.54 Characteristics of typical units for product class 1 described by manufacturers 

during interviews. 

CSL 

Example 

Application 

Rated 

Battery 

Energy 

Wh 

Rated 

Battery 

Voltage 

V 

Est. 

Time in 

Active 

h 

Est. 24-Hour 

Charge 

Energy 

Wh 

Est. 

ActiveOnly 

System 

Eff. 

Est. 

Maint. 

Power 

W 

Est. 

NoBattery 

Power 

W 

UEC 

kWh/yr 

0 Toothbrush 1.5 3.6 24.0 26.7 6% 1.2 0.5 10.0 

1 Toothbrush 1.5 3.6 24.0 19.3 8% 0.8 0.4 7.0 

2 Toothbrush 1.5 3.6 24.0 10.8 14% 0.4 0.2 3.5 

3 Toothbrush 1.5 3.6 24.0 5.9 25% 0.2 0.1 1.5 

5.6.8.2 CSL 0—Baseline—Baseline (UEC less than 10 kWh/yr) 

Manufacturer Interview Results 

The baseline unit represents BCs intended to inductively charge nickel-cadmium 

batteries. Although many of these were designed as long as 10 years ago, they continue to be 

sold in the market albeit at the lower price points. 

Like other chargers in this product class, units meeting the baseline CSL were designed 

for an electric toothbrush application. As such it is composed of two enclosures: a charging stand 

that connects directly to AC mains and serves as the transmitter in the inductive link, followed 

by a receiver and charge controller in the handle of the toothbrush. Because of the inductive 

connection—which transfers power through magnetic coupling between transmitter and receiver 

coils when they are in close proximity—both enclosures are sealed, allowing them to be used in 

a wet environment. 

What distinguishes the baseline units from units at the other CSLs is the slow charge rate 

and lack of termination. The charge acceptance of a nickel cell decreases as the battery 

approaches full charge, resulting in less charge in the cell for each unit of charge delivered by the 

BC. Because it spends more time in this inefficient region of cell operation, the slow baseline 

unit encounters significant active mode losses. 

These active-mode losses are compounded by the lack of termination. Rather than turn 

off the current to the battery after a full charge, the baseline unit continues to provide a small but 

not insignificant current, resulting in an input power around 1 watt in active and maintenance 

modes. No-battery power is less than 0.5 watts, while the resultant annual energy consumption is 

less than 10 kilowatt-hours. 

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5.6.8.3 CSL 1—Improved (UEC less than 7 kWh/yr) 

Manufacturer Interview Results 

Manufacturers have been able to improve the performance of the baseline charger by 

substituting in energy-saving components and making other incremental improvements to the 

design. Although many are still nickel-chemistry trickle chargers, units meeting CSL 1 save 

energy over the baseline by using more efficient subcircuits and components, such as lower-loss 

biasing of the input stage or higher-efficiency Schottky diodes in the inductive receiver. Schottky 

diodes have half the forward voltage drop of conventional silicon pn-junction diodes, resulting in 

half the losses. 

The above improvement in biasing circuitry would reduce annual energy consumption 

below 7 kilowatt hours and place these units into CSL 1. Specifically, the improvements in the 

biasing circuitry would reduce the no-battery power to less than 0.5 watts. This, combined with 

the component improvements, yields input power less than 0.75 watts in active and maintenance 

modes, resulting in an annual energy consumption less than 7 kilowatt-hours. 

5.6.8.4 CSL 2—Best-in-Market (UEC less than 3.5 kWh/yr) 

Manufacturer Interview Results 

Currently, the best-in-market models in this product class ship with lithium-ion 

toothbrushes. Even though lithium-ion cells have a nominal voltage of 3.6 volts (as opposed to 

1.2 volts for the nickel cells described previously), the manufacturers considered the utility and 

design of the lithium-ion best-in market unit to be comparable to the nickel units at the lower 

CSLs. 

Specifically, one can redesign the CSL 0 or CSL 1 units to meet CSL 2; however, it may 

require improvements in all three modes of operation: active, maintenance, and no-battery. 

Active-mode efficiency can be increased by improving the inductive coupling between the 

transmitter and receiver by placing a resonant capacitor in series with the receiver coil or by 

inserting additional ferrite material (which channels the magnetic field) in the charging stand. 

Such improvements result in a 5 percentage-point higher active mode efficiency over a typical 

CSL 1 unit.. 

However, according to manufacturers, the biggest gains can be made in the non-active 

modes. Because it charges a lithium-ion battery, which cannot tolerate a continuous trickle 

current, the best-in-market unit terminates following a full charge. Possible further 

improvements include reducing the clock speed of the microcontroller or dimming the 

informational LEDs located in the toothbrush handle. In total, these result in decreased input 

power during maintenance mode below 0.5 watts, while leaving no-battery power unchanged. 

The resulting annual energy consumption is less than 3.5 kilowatt-hours per year. 

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5.6.8.5 CSL 3—Max-Tech (UEC less than 1.5 kWh/yr) 

Manufacturer Interview Results 

During interviews, manufacturers also discussed potential efficiency improvements 

beyond the best-in-market level. According to manufacturers, technology options exist that can 

decrease energy consumption in all three modes of operation. 

First, manufacturers recommended improving the coupling between the toothbrush 

handle and charger base through the addition of an extra coil, which could increase the 

proportion of power transferred to the handle through resonance. Additionally, manufacturers 

suggested slowing the microcontroller clock and dimming the status indicators (LEDs or LCD 

backlights), which would decrease energy consumption in both active and maintenance modes. 

Even with these improvements, the inductive connection would limit the overall system 

efficiency in active mode to 25 percent. These design options, along with incremental 

improvements in the charging base, can be expected to decrease the annual energy consumption 

below 1.5 kilowatt-hours per year. 

5.6.8.6 Estimate of Manufacturer Selling Price 

Because of an inability to perform meaningful teardowns, the MSPs for this product class 

were based on the manufacturer interviews, and are pictured in Figure 5.48 and detailed in 

Table 5.55. 

$1.0

$1.5

$2.0

$2.5

$3.0

$3.5

$4.0

0 5 10 15

Manufacturer Selling Price [$]

Energy Consumption [kWh/year]

Mfr Interview Data

CSL1 CSL0

CSL2

CSL3

Figure 5.48 Illustration of the MSP for this representative unit at each CSL. 

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Table 5.55 Comparison of MSPs for product class 1’s representative unit obtained from 

manufacturer interviews. No teardowns were performed for this representative unit. 

MSP from MSP from 

UEC Interviews Teardowns 

CSL kWh/yr 2009$ 2009$ 

0 10.0 2.05 -

1 7.0 2.22 -

2 3.5 2.45 -

3 1.5 2.60 -

5.6.8.7 Scaling of CSLs within Product Class 

DOE welcomes comment on potential strategies for scaling results of the representative 

unit analysis to other BCs in this product class. 

5.6.9 Representative Product Class 2: Low Energy, Low Voltage 

The low-energy, low-voltage product class includes BCs for batteries below 4 volts and 

below 100 watt-hours. It represents the low end of battery energy, and includes BCs for 

telephony, personal care, and portable entertainment applications. DOE analyzed this 

representative product class due to the large shipments of products in this category. 

BCs in this representative product class charge batteries composed of lithium-ion, nickelcadmium, or nickel-metal hydride cells. Because the nominal voltage of a lithium-ion cell is 

3.6 volts, there are no BCs for lithium-ion batteries in the lower portion of the voltage range; 

instead in this range DOE found BCs for nickel-based batteries with one or two cells (nickel cells 

have a nominal voltage of 1.2 volts). At or above 3.6 volts, either battery chemistry can be used; 

however, applications that are smaller, lighter, or more expensive tend to use lithium-ion 

batteries, while the remainder use nickel batteries. 

To ensure an analysis applicable to BCs for lithium-ion as well as the two nickel 

chemistries, DOE selected a 3 watt-hour, 3.6 volt charger as its representative unit. That energy 

and voltage is characteristic of batteries of all three chemistries as well as a wide range of 

applications. 

5.6.9.1 Units Analyzed 

DOE tested 19 units for this representative product class; their annual energy 

consumption, assuming a shipment-weighted product class-average usage profile, is pictured in 

Figure 5.49. For comparison, the figure also includes the results of tests conducted by Ecos 

Consulting.2 Of these, DOE chose four units for further evaluation and teardowns based on their 

efficiency test results and internal design. Detailed information regarding these four units is 

presented in Table 5.56. 

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0

5

10

15

20

25

0 2 4 6 8 10 12 14 Annual Energy Consumption [kWh]

Measured Battery Energy [Wh]

Cordless Phones

Cordless Phones/Answering Devices Mobile Phones

Cordless Rechargeable Can Openers

Digital Cameras

Portable Video Game Systems

Ecos Tests

Rep. Unit

Efficiency Improvement Path Increasing Efficiency

Figure 5.49 Test results for representative product class 2: Low Energy, Low Voltage. 

As can be seen in Figure 5.49, the majority of products tested in this product class have a 

battery energy less than 5 watt-hours, with the exception of the cluster of Ecos test points at 

approximately 10 watt-hours. These correspond to tests of universal battery chargers for 

standard-sized AA or AAA batteries, performed with the highest number of batteries these units 

could charge (typically 4). However, Ecos also tested these same units with the smallest 

allowable number of batteries, whereupon the measured battery energy ranged from 0.9 to 

2.2 watt-hours—within the main cluster of battery energies. DOE therefore focused its analysis 

on units at approximately 3 watt-hours to make its analysis applicable to the widest range of BCs 

in this class, including the universal battery chargers. 

From these, DOE selected several units for further analysis based on their measured 

energy consumption, detailed in Table 5.56. These units were selected to span a wide range of 

efficiencies available in the market. The only BCs that lie outside this efficiency distribution are 

the Ecos test units with annual energy consumption above 10 kilowatt-hours per year. 

In its test results database, Ecos lists these all as cordless phones/answering devices, and 

despite a thorough search, DOE was unable to find any cordless phones with energy 

consumption at those levels. This discrepancy between the lowest-efficiency units tested by DOE 

versus Ecos may be due to the vintage of the units tested by Ecos (2007, prior to the efficiency 

impacts of EISA 2007) and the potential energy consumption of answering machine features. In 

either case, establishing the baseline CSL at the energy consumption of a current BC (with an 

EISA-compliant EPS) unburdened by any additional non-battery charging functionality, is the 

preferred approach. 

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Table 5.56 Detailed test results for the units corresponding to the CSLs for representative 

product class 2: Low Energy, Low Voltage. 

CSL 

Application 

Battery 

Energy 

Wh 

Rated 

Battery 

Voltage 

V 

Est. 

Time in 

Active 

h 

24-Hour 

Charge 

Energy 

Wh 

ActiveOnly 

System 

Eff. 

Maint. 

Power 

W 

NoBattery 

Power 

W 

UEC 

kWh/ 

yr 

0 - - - - - - - - -

1 

Cordless 

Phone 2.9 3.6 21.4 33.5 10% 1.4 0.3 6.0 

2 

Digital 

Camera 

Digital 

Camera 

2.8 

2.8 

3.7 

3.7 

2.6 

2.0 

8.8 

7.5 

45% 

54% 

0.1 

0.1 

0.1 

0.1 

1.2 

1.0 

3 - - - - - - - - -

Manufacturer interviews further influenced DOE’s decision to set the baseline for this 

representative unit at a higher UEC than that of the least efficient unit tested. Several 

manufacturers described line-frequency BCs currently in production with annual energy 

consumption higher than 5.1 kilowatt-hours. Typical performance of these manufacturer 

described baseline units can be seen in Table 5.57, next to the performance of higher-efficiency 

manufacturer units. 

Table 5.57 Characteristics of typical units for product class 2 described by manufacturers 

during interviews. 

CSL 

Example 

Application 

Rated 

Battery 

Energy 

Wh 

Rated 

Battery 

Voltage 

V 

Est. 

Time in 

Active 

h 

Est. 24-Hour 

Charge 

Energy 

Wh 

Est. 

ActiveOnly 

System 

Eff. 

Est. 

Maint. 

Power 

W 

Est. 

NoBattery 

Power 

W 

UEC 

kWh/yr 

0 Power Tool 3 3.6 22.0 41.1 8% 1.8 0.7 10.0 

1 

Cordless 

Phone 3 3.6 14.5 31.3 14% 1.1 0.4 6.0 

2 Cell Phone 3 3.6 6.9 9.8 79% 0.4 0.1 1.2 

3 - - - - - - - - -

DOE seeks comment on whether 10 kilowatt-hours per year is a valid baseline for this 

representative unit—i.e., whether there are significant shipments of this representative unit at this 

UEC—despite the apparent lack revealed through testing. Finally, since there are units with this 

UEC within this product class, but not with the same characteristics as the representative unit 

(they have slightly different battery energies), DOE also seeks comment on whether teardowns 

of units with slightly lower or higher measured battery energy could nonetheless be used in the 

analysis of this representative unit. 

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5.6.9.2 CSL 0—Baseline (UEC less than 10 kWh/yr) 

Test and Teardown Results 

As mentioned above DOE did not tear down any products at the baseline CSL, due to a 

lack of product with this efficiency at the representative unit battery voltage and energy. For the 

later analyses (life-cycle cost and national impacts analyses), DOE therefore used the results 

from the test and teardown unit at CSL 1 as the baseline, with the result that there was no 

significant impact from a standard set at CSL 1. See chapters 8 and 10 for more information. 

Manufacturer Interview Results 

Although manufacturers discussed the full range of efficiency for this product class, 

chargers at the baseline efficiency in practice are limited to infrequently charged applications 

used around the home, such as cordless telephones and handheld vacuum cleaners. The least 

efficient chargers in this class are slow, which makes them useful primarily for applications that 

are used infrequently and otherwise left for long periods in maintenance mode. Because they 

have to dissipate more heat, the less-efficient baseline chargers are also typically more bulky 

than chargers at higher CSLs, again relegating them to those same applications, which need not 

be portable. 

The baseline charger typically consists of a trickle charger for a nickel battery. The power 

conversion is performed by a line-frequency transformer followed by a half-wave or bridge 

rectifier. The impedance of the transformer windings typically performs charge control. 

As in the case of the inductive baseline unit, the slow charge rate results in large 

recombination losses in the battery. Active-mode efficiency (including the battery) can be as low 

as 10 percent, though typically varies between 30 and 60 percent. Maintenance mode power, due 

to the constant trickle current, is around 2 watts, while no-battery power—driven primarily by 

magnetization losses in the transformer—can be as high as 1 watt. This performance results in an 

annual energy consumption below 10 kilowatt-hours. 

5.6.9.3 CSL 1—Improved (UEC less than 6 kWh/yr) 

Test and Teardown Results 

Disassembly of the CSL 1 unit for this product class revealed a line-frequency design (the 

baseline topology described by manufacturers), though with certain efficiency improvements, 

likely prompted by the mandatory EPS efficiency standards put in place by EISA 2007. For 

instance, the charger wall adapter uses higher-grade transformer steel, resulting in a particularly 

low no-load power (0.29 watts), which results in the equally low no-battery power listed in 

Table 5.56. 

Furthermore, the rectifier is composed of four 1N5818 power Schottky diodes. With 

roughly half the forward voltage drop, and consequently half the losses, of conventional silicon 

diodes, these Schottkies contribute to the baseline unit’s improved efficiency in active mode, 

especially in relation to some of the units tested by Ecos Consulting in 2007. As no dedicated 

charge control components were found, the transformer inductor windings are assumed to 

perform this function. 

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OUT

OUT BATT

R

V V

I

As can be seen in Figure 5.50(b), the initial portion of the input power waveform during 

charge mode displays the decaying exponential characteristic typical of line-frequency slow 

chargers. This characteristic is due to the relationship between charger output current and battery 

voltage. In this type of charger, the current is proportional to the battery voltage per Eq. 5.2. 

, 

Eq. 5.2 

Where: 

I is the charge current; 

VOUT is the charger output voltage; 

VBATT is the battery voltage; and 

ROUT is the output impedance of the charger, typically due to the transformer windings, 

which performs charge control. 

As the battery recharges, its voltage increases, decreasing the charge current and slowing 

the rate of charge, resulting in an exponential input power characteristic. Even though the input 

power for this charger is fairly low, the long charge time, and in particular the time spent at high 

state-of-charge, a shortcoming cited by manufacturers during interviews, contributes to the active 

mode losses in this charger. 

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(a) (b) 

Figure 5.50 Input power waveform during charge and maintenance modes for the baseline 

unit. The full 24-hour plot (a) shows some increased activity in maintenance, possibly associated 

with phone operation, while the six-hour fragment (b) shows the exponential characteristic 

typical of slow chargers. 

Manufacturer Interview Results 

In general, manufacturers agreed with the teardown results, and suggested that small 

improvements to the baseline unit (CSL 0) can be made through the use of termination timers or 

improved transformer steel. Nonetheless, they mentioned that a significant decrease in annual 

energy consumption can only be achieved by moving to a switched-mode topology. 

By using a high-frequency switched-mode—rather than line-frequency—power supply to 

perform power conversion, a manufacturer not only decreases power conversion losses but can 

also increase charge rate, j decreasing recombination losses in the battery. Recombination losses 

occur inside the nickel battery—which remains popular among many of the applications served 

by BCs in this product class—especially as it approaches full charge. By spending less time at 

this high state-of-charge, less of the charger output energy is consumed by recombination, 

resulting in lower overall losses. 

The typical active mode efficiency (including losses in the battery) of a switched-mode 

BC meeting this CSL are above 50 percent, though some line frequency chargers still exist, with 

active mode efficiency as low as 14 percent. Maintenance mode power ranges between 0.5 and 

1.3 watts, while no-battery mode power is typically no more than 0.4 watts. The annual energy 

consumption is less than 6 kilowatt-hours. 

j Because a switched-mode power supply is more efficient, it dissipates less heat, allowing it to be placed in a 

smaller package. Alternatively, one could also keep the same package, but increase output power until the power 

dissipated as heat reaches the limits of the original package. This higher output power allows one to charge a battery 

at a much faster rate (e.g., 3 hours instead of 16) while maintaining the same charger size. 

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5.6.9.4 CSL 2—Best-in-Market (UEC less than 1.2 kWh/yr) 

Test and Teardown Results 

To decrease the energy consumption of the baseline unit, a manufacturer needs to move 

to a switched-mode power supply, which is one of the efficiency improvements in the digital 

camera chargers at CSL 2, the performance of which is detailed in Table 5.56. 

The two digital cameras differ both in physical form and internal construction. The first 

charger listed in Table 5.56, which is slightly less efficient, charges an internal lithium-ion 

battery and is therefore composed of two enclosures connected by a USB cable—a wall adapter 

and additional electronics inside the camera body. The more efficient unit charges an external 

lithium-ion battery, and has both power supply and charge control circuitry integrated into a 

single enclosure that plugs directly into mains. The best-in-market CSL can therefore be met by 

chargers for both external as well as internal batteries, cable losses notwithstanding. 

Furthermore, the CSL can also be met by chargers for other applications—one of the other units 

at CSL 2 torn down by DOE was a video game charger, though that particular unit has been 

excluded from the analysis because a microcontroller that was used for both battery charging and 

other functions inflated its cost past the point where it was comparable to the other chargers. 

An interesting difference between the two camera chargers lies in their choice of power 

supply topology. As can be seen in Figure 5.51, the switched-mode power supply for the 

slightly-less efficient charger does not have an integrated controller IC, relying instead on a 

ringing-choke converter (RCC) topology, which nonetheless manages to achieve an active mode 

efficiency of 75 percent when tested according to the EPS test procedure. The power converter 

circuit of the other charger features a flyback design; its efficiency independent of the battery is 

unknown because of the inability of the EPS test procedure to test chargers that connect directly 

to an external battery. 

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Figure 5.51. The top and bottom of the slightly less-efficient best-in-market camera charger. 

Note the lack of any integrated circuit controller. 

As can be expected, both chargers have additional circuitry beyond the power supply 

because of the sensitive nature of lithium-ion batteries. In particular, lithium battery charging 

requires a microcontroller or dedicated charge-management IC, as can be seen in Figure 5.52, 

increasing the charger’s cost. Nonetheless, these charge management ICs are necessary to 

provide not only safety, but also low energy consumption during maintenance and no-battery 

modes expected of best-in-market BCs. 

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Figure 5.52 PCBs of digital camera chargers meeting CSL 1. Note the highlighted 

microcontroller in a black 14-pin surface-mount package in the left photograph. Similar 

functionality is provided in the other charger by the dedicated charger IC highlighted at the right. 

In particular, the charge and maintenance waveforms for the two camera chargers are 

pictured in Figure 5.53 and Figure 5.54, below. As can be seen, the maintenance mode power is 

approximately 0.1 watts for both chargers. This is likely accomplished through a combination of 

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minimal no-load/low-load losses in the wall adapters and effective power management in the 

end-use application using the ICs mentioned previously. 

Finally, the no-battery power for the best-in-market chargers is also approximately 

0.1 watts. Since no-battery power is in many cases analogous to EPS no-load power,k the two 

can be compared, and based on the responses obtained during the EPS manufacturer interviews 

(summarized in section 5.4 specifically5.4.8), these power levels are near the theoretical 

minimum achievable with today’s technology. 

Figure 5.53Fragment of the input power waveform during charge and maintenance modes 

for the less efficient CSL2 digital camera charger. 

k In many cases, such as all integral-battery products powered by wall adapters, the two are equivalent. 

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Figure 5.54 Fragment of the input power waveform during charge and maintenance modes 

for the more efficient CSL2 digital camera charger. 

Manufacturer Interview Results 

Manufacturers can achieve the best-in-market CSL through component improvements in 

the power supply stage such as lower-loss diodes or switching transistors. Manufacturers also 

recommended upgrading the integrated-circuit (IC) controller that manages the operation of the 

power supply, permitting lower-power operation in low- and no-load modes through cycle 

skipping and frequency foldback. 

Even lower energy consumption can be achieved through additional circuit 

improvements, though the gains at this stage are limited. The few manufacturers that addressed 

annual energy consumption below 2.5 kilowatt-hours mentioned synchronous rectification as a 

way to improve active-mode efficiency by a percentage point, though they characterized this as 

more of a max-tech option. Further improvements in the IC controller could decrease the nobattery power to 0.1 watts, though still lower power levels could result in a power supply that is 

not sufficiently responsive to the demands of the load (the downstream components of the 

charger as well as any additional functionality). 

Using the above strategies, manufacturers can increase the system-wide efficiency above 

70 percent. BCs meeting this CSL also exhibit improvements in maintenance and no-battery 

power, which are below 0.4 and 0.1 watts, respectively, consistent with that found through 

teardowns. These energy consumption figures, combined with the average usage profile for this 

product class lead to a typical annual energy consumption below 1.2 kilowatt-hours. 

5.6.9.5 CSL 3—Max-Tech 

Test and Teardown Results 

No analysis of the maximum-technologically feasible efficiency for this representative 

product class has been performed to date. 

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Manufacturer Interview Results 

As mentioned before, DOE testing demonstrated that some units currently in the market 

offer comparable performance to the max-tech units described by manufacturers. Consequently, 

the manufacturer ―max-tech‖ design options for this and some other representative units have 

been subsumed under the best-in market CSL 2, while DOE continues to investigate more 

efficient designs. 

5.6.9.6 Estimate of Manufacturer Selling Price 

The MSPs derived from teardowns and manufacturer interviews are pictured in Figure 

5.55and detailed in Table 5.58 for each CSL. The manufacturer MSPs are an aggregate of the 

costs provided by manufacturers, appropriately marked up, while the teardown MSPs correspond 

to the MSP of the cordless phone charger for CSL 1 and the average of the two camera chargers 

for CSL 2. No unit meeting the baseline CSL was torn down. 

$0

$3

$6

$9

$12

$15

0 5 10 15

Manufacturer Selling Price [$]

Energy Consumption [kWh/year]

Mfr Interview Data

Test and Teardown Data

CSL0

CSL1

CSL2

Figure 5.55 MSPs for each CSL for representative unit 2. 

Table 5.58 Comparison of MSPs for product class 2’s representative unit obtained from 

manufacturer interviews versus those developed through teardowns. 

MSP from MSP from 

UEC Interviews Teardowns 

CSL kWh/yr 2009$ 2009$ 

0 10.0 0.62 -

1 6.0 1.09 0.62 

2 1.2 11.71 2.62 

3 - - -

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5.6.9.7 Scaling of CSLs within Product Class 

As mentioned in section 5.6.9.1, above, this product class includes univeral battery BCs, 

which typically charge either 1, 2, or 4, AA or AAA standard-sized batteries. Furthermore, DOE 

received from Pacific Gas & Electric the results of tests performed on several of these chargers. 

These test results, illustrated in Figure 5.56, could serve as the basis for scaling the analysis 

results to all chargers within this representative product class. 

Figure 5.56 Results of universal battery charger test results performed by Ecos Consulting 

with batteries of varying energies. All test results for a given charger are performed with 

batteries with the same voltage. 

5.6.10 Representative Product Class 4: Low Energy, High Voltage 

The low-energy, high-voltage product class includes BCs for batteries from 10 to 48 volts 

and less than 100 watt-hours, in particular the majority of BCs used with notebook computers, 

power tools, hedge and weed trimmers, and handheld vacuums. The notebook computer BCs 

tend to cluster around 11 volts and 20 to 55 watt-hours, while the remaining applications tend to 

span the voltage range between 10.8 and 24 volts, though with lower battery energies. 

(Manufacturer views regarding this division are summarized in section 5.6.5.) DOE analyzed this 

representative product class because the mid-range shipments numbers (millions to tens of 

millions of units per year) combine with mid-range unit energy consumption to result in 

significant shipment-weighted energy consumption. 

The battery voltage and energy for all the applications in this product class, obtained 

from the market survey, are illustrated in Figure 5.57. 

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Figure 5.57 Illustration of the limited overlap in BC characteristics between notebook 

computers and motor-operated appliances in the low-energy high-voltage product class 

(based on advertised battery voltage and energy). 

To ensure an analysis representative of all the applications in this product class, DOE 

chose as its representative unit a BC with a 10.8 volt, 20 watt-hour battery, which falls at the 

overlap of the notebook computer and power tool ranges discussed above. The limited overlap 

between the major applications in this product class made it difficult for DOE to test BCs from 

both applications with the same battery voltage and energy. However, even though the 

characteristics of the BCs tested during this analysis differed somewhat from the representative 

unit and each other, these variations are small compared to the large differences in efficiency 

seen in the next section. 

5.6.10.1 Units Analyzed 

DOE tested eight units for this representative product class; their annual energy 

consumption, assuming an average usage profile, is pictured in Figure 5.58. For comparison, the 

figure also includes the results of tests conducted by Ecos Consulting. Of these, DOE chose four 

units for further evaluation and teardowns based on their efficiency test results and internal 

design. Detailed information regarding the measured performance of these four units is presented 

in Table 5.59, while information on typical units provided by manufacturers appears in Table 

5.60. 

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0

10

20

30

40

50

60

0 20 40 60 80

Annual Energy Consumption [kWh]

Measured Battery Energy [Wh]

Power Tools

Notebook Computers

Ecos Tests

Rep. Unit

Efficiency Improvement Path

Increasing Efficiency

Figure 5.58 Test results for representative product class 4: Low Energy, High Voltage 

Table 5.59 Detailed test results for the units corresponding to the CSLs for representative 

product class 4: Low Energy, High Voltage. 

CSL Application 

Battery 

Energy 

Wh 

Rated 

Battery 

Voltage 

V 

Est. 

Time in 

Active 

h 

24-Hour 

Charge 

Energy 

Wh 

Active 

Only 

System 

Eff. 

Maint. 

Power 

W 

NoBattery 

Power 

W 

UEC 

kWh/y 

r 

0 Power Tool 16.3 12.0 0.6 167.5 56% 5.9 2.2 39.4 

1 Power Tool 13.4 12.0 0.9 52.6 69% 1.4 1.4 10.5 

2 

Notebook 

Computer 

Power Tool 

22.9 

15.2 

11.1 

12.0 

2.7 

0.6 

44.6 

29.3 

70% 

84% 

0.6 

0.5 

0.1 

0.5 

6.1 

3.8 

3 - - - - - - - - -

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Table 5.60 Characteristics of typical units for product class 4 described by manufacturers 

during interviews. 

CSL 

Example 

Application 

Rated 

Battery 

Energy 

Wh 

Rated 

Battery 

Voltage 

V 

Est. 

Time in 

Active 

h 

Est. 24-

Hour 

Charge 

Energy 

Wh 

ActiveOnly 

System 

Eff. 

Est. 

Maint. 

Power 

W 

Est. 

NoBattery 

Power 

W 

UEC 

kWh/yr 

0 Power Tool 20 10.8 13.0 142.9 19% 3.4 1.2 39.4 

1 

Notebook 

Computer 20 10.8 1.5 57.4 58% 1.0 0.5 10.5 

2 

Notebook 

Computer 20 10.8 1.0 42.5 76% 0.7 0.2 6.1 

3 - - - - - - - - -

As can be seen in Figure 5.58, all the BCs tested at the representative-unit battery energy 

and voltage were used to establish the CSLs for the low-energy high-voltage product class. Two 

BCs of comparable energy consumption were used as the basis for CSL 2 to make this analysis 

applicable to both major applications in this representative product class. 

Three BCs in Table 5.59 are standalone chargers for DIY power tools with external 

batteries. They consist of a single enclosure that contains the power conversion and charging 

circuitry and has a ―cup‖ that holds the battery during charging. One or two charge indicator 

LEDs are also present. The chargers are powered through a non-detachable AC line cord. 

The fourth BC, intended for notebook computer applications resides in two enclosures. 

One is a wall adapter with detachable AC line cord, while the other is the notebook computer 

itself, containing an integral battery. The wall adapter performs the AC/DC conversion, 

outputting a regulated 20 volts DC, while the charge control and battery monitoring is performed 

by circuits located on the computer motherboard, as shown in Figure 5.59. 

Figure 5.59 Photographs of the top and bottom of the motherboard of the notebook 

computer, with power management and battery charging components highlighted. 

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Despite their slightly different constructions, the four BCs provide comparable utility. 

Each has an output power between 36 and 47 watts, and while the AC/DC converters of the 

power tool chargers must convert to a lower voltage than that for the notebook computer 

(approximately 12 volts versus 20 volts), the latter must perform two-stage voltage conversion 

(from 120 volts AC to 20 volts DC to 12.3 volts DC). Lower output voltages and successive 

conversions decrease the conversion efficiency, which impacts the energy consumed in active 

mode. Because DOE’s analysis focused on these real-world BCs, it is applicable to a wide-range 

of BCs in this product class, regardless of their physical construction or inefficiencies due to the 

requirements of the end-use application. 

5.6.10.2 CSL 0—Baseline (UEC less than 39.4 kWh/yr) 

Test and Teardown Results 

DOE chose a 12 volt BC with a measured battery energy of 16.3 watt-hours and annual 

energy consumption of 39.4 kilowatt-hours as its baseline unit for this product class. The energy 

consumption of this unit was the highest of all the 12 volt units that DOE tested, and furthermore 

exceeded the energy consumption of the majority of BCs in this product class, regardless of 

battery voltage and energy. 

As can be seen in Figure 5.58, however, Ecos Consulting tested a power tool charger 

with a measured battery energy of 15.7 watt-hours that had an annual energy consumption of 

58.7 kilowatt-hours. Furthermore, because this was an 18 volt charger, one could expect its 

energy consumption to be even higher if the same design were applied to the lower-voltage 

representative-unit battery. Nonetheless, DOE did not use this or a similar BC as its baseline due 

to its slow charge rate: unlike most BCs in this product class, this charger did not terminate after 

a few hours of charging, and at the end of the 24 hour test was still drawing over 10 watts 

(compared to approximately 12 watts initially). Such behavior is atypical of BCs in this product 

class. 

During the market survey, DOE compiled information on 57 cordless power tools 

currently popular in the market. While not all the manufacturers listed the charge time, of the 28 

that did, the maximum charge time was 3 hours. Given this information, DOE does not expect 

slow chargers for power tools to be available in the future as consumers seek shorter charge 

times. Therefore, DOE considered the annual energy consumption of this slow 18 volt, 

15.7 watt-hour charger to be an outlier and set its baseline at the energy consumption of the least 

efficient fast charger, described below. 

The baseline unit charges nickel-cadmium batteries for power tool use. Its design consists 

of a flyback converter, with some additional circuitry to control the charging of the battery. For 

example, in contrast to AC/DC converters that serve as voltage sources (e.g., EPSs), the baseline 

BC unit has two optocouplers. As in an EPS, the first is likely intended to send feedback signals 

related to the output voltage from the secondary to the primary sides of the power converter, 

while the second likely controls the charging current. 

As can be seen in Table 5.59, the baseline unit has a low 24-hour energy efficiency 

(approximately 10 percent), calculated by dividing the battery discharge energy by the energy 

consumed by the charger over a 24-hour charge and maintenance cycle. However, this low 

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EACTIVE

 

performance is not due to low power conversion efficiency in the AC/DC converter. In fact, if 

one examines only the initial portion of the 24-hour test, when the battery is actively charging, 

up to the point where the charger enters maintenance mode, the charger energy consumption is 

only 29 watt-hours, for an active -only battery charging system efficiency of: 

56.2 percent

29 watt- hours

16.3watt- hours

ACTIVE

BATT

ACTIVE E

E

Eq. 5.3 

where: 

ACTIVE EBATT

is the active-only efficiency; 

is the energy recovered from the battery during discharge; and 

is the energy consumed by the charger during active mode, as defined through 

the examination of the input power measurements presented in Figure 5.58. 

The inefficiency, therefore, occurs in maintenance mode. Because the charge time for this 

BC is only 0.6 hours, the high input power in maintenance mode (almost 6 watts) dominates the 

24-hour combined charge and maintenance efficiency. This high energy consumption is not due 

to overhead losses in the charger, but rather to an inefficient maintenance strategy, which uses 

high-current pulses to periodically ―top off‖ the battery. While topping off the battery may be 

beneficial over the long run, it should not be implemented immediately after the battery has 

finished charging. 

As can be seen in Figure 5.60, the input power of the baseline unit following the full 

charge is periodic in time, with each of the spikes in the figure lasting approximately 2 minutes, 

consuming an additional 1.1 watt-hours, and delivering a significant portion of that energy to the 

battery after it has already been fully charged. Not only does this result in inefficient operation, 

but the resulting elevated temperature also decreases battery lifetime. 

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Figure 5.60 The input power of the baseline unit during charging and maintenance modes. 

The overall efficiency of the baseline unit is further compromised by the choice of 

components. None are optimized for energy efficiency. For example, the design relies on 

standard pn-junction diodes for output rectification, while the switching is performed by a 

generic UC3842-series PWM controller, which draws up to 17 milliamperes with a supply 

voltage above 10 volts DC and a frequency in the 50 kilohertz range. In sum, the baseline unit 

has an annual energy consumption of 39.4 kilowatt-hours. 

Manufacturer Interview Results 

Despite the decreasing popularity of slow chargers for power tool operation, 

manufacturers focused on them when discussing the baseline CSL. Nonetheless, not all 

applications can tolerate the long charge times of slow chargers: given an ideal battery, they 

should take 10 hours to charge; however, due to recombination losses in the nickel battery, 

typical charge times are on the order of 16 hours. 

On the contrary, BCs for professional power tools typically recharge the battery in 

1 hour, while those for notebook computers in 2 to 3 hours. Manufacturers described such fast 

chargers as relying on a high-frequency switched-mode topology because the size of a linefrequency transformer that could provide the power necessary to recharge the battery in such a 

short time would be too large to be economical or user-portable. Nonetheless, not all switchedmode power supplies are naturally efficient. Some manufacturers have been producing the same 

BCs for upwards of 10 years, and neither the power supply nor the charge control circuitry has 

changed to take advantage of the latest energy efficient technology. 

According to manufacturers, these inefficient fast BCs typically consist of a non-isolated 

switched mode power supply (all other components of the charger, including the battery charging 

terminals, are then inaccessible to the user to prevent electrical shock). Iron-core isolated power 

supplies are similarly inefficient. Finally, the remainder of the charger design has not been 

optimized with regards to energy efficiency. This results in either high overhead losses or 

preventable losses from other system components (particularly in applications where the charge 

is embedded inside the end-use product). 

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As a result, the active mode efficiency of these battery chargers (including the efficiency 

of the typical nickel-cadmium batteries) is around 55 percent. The maintenance mode power 

ranges between 2 to 6 watts (with the higher number comparable to the teardown unit) while the 

no-load power ranges between 1 to 2 watts. Annual energy consumption is less than 

39.4 kilowatt-hours. 

5.6.10.3 CSL 1—Improved (UEC less than 10.5 kWh/yr) 

Test and Teardown Results 

The BC unit associated with CSL 1 is also a fast power tool charger, with a 12 volt, 

13.4 watt-hour battery. In contrast to the baseline unit, the CSL 1 unit does not continue to 

charge the battery in maintenance. The lithium-ion battery would not tolerate it.l Instead, as can 

be seen in Figure 5.61, the input power to the unit drops to 1.4 watts. As can be seen in Table 

5.59, this is also the input power to the unit in no-battery mode, when the battery is removed 

from the charger. Since the BC draws the same power whether or not the battery is present, this 

indicates that maintenance mode power is already as low as possible. Further improvements can 

only be made by focusing on the overhead power dissipation of the electronics, such as the onboard microcontroller, op-amp, voltage reference, etc., which impact both no-battery and 

maintenance modes. 

Figure 5.61Fragment of the input power waveform during charge and maintenance modes 

for the CSL 1 unit. 

The conversion efficiency of this BC is also improved over the baseline unit. Unlike the 

baseline, the CSL 1 unit uses a Schottky diode for rectification, which has a lower voltage drop, 

resulting in lower power dissipation during charging and higher active mode efficiency. 

Nonetheless, the design evaluated for CSL 1 continues to use UC3842-series PWM controller to 

drive the switching FET. As mentioned previously, the high supply current requirements of this 

l Unlike nickel-based batteries, lithium-ion batteries cannot tolerate overcharge so lithium-ion chargers must 

terminate following full charge. 

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controller limit the maximum active mode efficiency and minimum maintenance and no-battery 

power. 

Manufacturer Interview Results 

Manufacturers proposed numerous design options for improving the performance of the 

baseline charger. These ranged from moving to a switched-mode topology and termination for 

the slow chargers, to various incremental circuit improvements for the fast chargers. 

To improve the efficiency of the slow charger, manufacturers recommended 

implementing termination—cutting off the charge current following the recharge—using either a 

timer or state-of-charge sensor. Although that would decrease maintenance mode current, that 

alone may not be enough. To decrease energy consumption in all three modes, manufacturers 

also recommended improvements to the line-frequency transformer core steel (resulting in lower 

magnetization losses) or a complete transition from line-frequency to high-frequency switchedmode topology, similar to that currently used for fast chargers. 

For fast chargers, which already used switched-mode designs, but often inefficiently, 

manufacturers recommended incremental circuit improvements. According to interviewees, 

replacing any silicon output diodes with Schottkies could significantly decrease energy 

consumption. This is consistent with what was seen in the teardowns. Other incremental 

improvements included improvements to the passives, such as inductors with lower parasitic 

resistances and lower-leakage filter capacitors. 

As an alternative path to reaching CSL 1, some manufacturers recommended more 

efficient charge control, for example using buck converters as opposed to linear regulators to 

adapt the power supply output to the requirements of the battery charging stage. 

Finally, some of the manufacturers focused on minimizing maintenance and no-battery 

power, which manufacturers mentioned are often indistinguishable from each other, a fact also 

evidenced by DOE testing. For instance, one manufacturer suggested adding an electromechanical switch that would disconnect the charger once the battery is removed (only practical 

for chargers with external batteries)), while another spoke of replacing the components that 

enable communication between the BC and the battery-pack electronics. The newest generation 

of these components, although more expensive, has lower standby losses, leading to lower BC 

energy consumption in standby and maintenance modes. 

The above design options, either singly or in combination, could improve the energy 

efficiency of the baseline unit to the CSL 1. In particular, the active mode efficiency of the entire 

battery charging system could increase from 55 percent to 65 or 70 percent, while the 

maintenance power could decrease below 2 watts (consistent with testing), and the no-battery 

power below 1 watt. Implementing the automatic disconnect switch could eliminate no-battery 

power to 0 watts. The resultant annual energy consumption is less than 10.5 kilowatt-hours. 

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5.6.10.4 CSL 2—Best-in-Market (UEC less than 6.1 kWh/yr) 

Test and Teardown Results 

As mentioned previously, DOE identified two units that exhibited an annual energy 

consumption superior to all other BCs tested in this product class. These two units demonstrate 

that this level of energy consumption is commercially achievable for both power tools and 

notebook computers, the two major applications in this product class. Because of their lithiumion batteries, both BCs must use efficient maintenance-mode strategies that cut off current to the 

battery, such that—as seen previously—their input power in maintenance is equal to the input 

power in no-battery mode and due entirely to the overhead power of the control electronics. 

In the case of the power tool charger, these electronics are fairly efficient and include a 

Schottky diode for rectification, reducing energy consumption during power conversion 

associated with charging. The BC also features a more efficient PWM controller, which 

integrates the controller and FET into a single package with a maximum supply current of 1.3 to 

2.0 milliamperes, depending on the switching frequency. This is an order of magnitude less than 

that of the controller in the baseline and CSL 1 units. 

The design of the BC for notebook computer applications demonstrates alternate methods 

of reaching CSL 2 and maintaining energy consumption below 4.2 kilowatt-hours per year. 

Unlike the power tool chargers examined earlier, this BC features a two-stage architecture, with 

an external power supply with an industry-standard regulated 20 volt DC output, followed by a 

battery charger embedded inside the application. 

The EPS uses Schottky diodes for rectification, resulting in lower forward voltage drops 

across the rectifier and higher conversion efficiency in active mode. The EPS also features a 

more efficient PWM controller for driving the switching FET, with a maximum supply current of 

1.2 to 2.0 milliamperes, depending on the switching frequency. 

The charger portion of the BC internal to the notebook computer uses a dedicated 

integrated circuit (IC) for charge control. This IC consists of a DC/DC buck converter, which 

reduces the 20 volt input from the EPS to a lower voltage suitable for the 11.1 volt lithium-ion 

battery, while monitoring the current and voltage to the battery to ensure safe charging. 

Although a two-stage architecture typically introduces further losses into a battery 

charging system,m these are lowered by using a switched-mode second stage. Synchronous 

rectification used on the output of this second stage makes it even more efficient and puts this 

BC on par with the best-in-market single-stage BC. Nonetheless, a two-stage solution does offer 

some benefits. As can be seen in Table 5.59, the input power during no-battery mode is six times 

less than that during maintenance mode. 

This is not due to any detection of the presence of the battery (another design option), but 

is simply achieved by disconnecting the entire second stage together with the battery. Because 

the notebook computer has an integral battery, a user does not remove it from the application for 

m The efficiencies of each stage are multiplied together to arrive at the system-efficiency, such that two 90-percentefficient stages will result in a system with only 81 percent efficiency. 

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recharging; rather, the user connects the entire application—the computer, the battery, and the 

second-stage battery charging electronics—to the EPS. In no-battery mode, the inverse is true, 

with the notebook computer disconnected and the EPS the only part of the product connected to 

the AC line. Therefore, the second stage and other potential sources of loss from the computer 

power-management circuitry are no longer present, decreasing the input power compared to that 

in maintenance mode. Such a strategy could have broader applicability beyond notebook 

computers, as additional electronics continue to be packaged with detachable batteries for such 

applications as power tools, and was in fact called out by manufacturers during interviews as a 

possible efficiency design option. 

Manufacturer Interview Results 

Manufacturers agreed that no slow-charger design could meet the best-in-market CSL. As 

a result, all applications that currently use slow chargers would need to convert to fast chargers 

to meet this CSL; however, this should only improve consumer utility. Furthermore, the majority 

of chargers at this CSL utilize lithium-ion batteries, which manufacturers agreed offer increased 

electro-chemical efficiency during charge and discharge. The drawback of lithium-ion is that 

because of their sensitive nature, these batteries require constant supervision using dedicated 

safety circuits, a burden which continues to make nickel-metal hydride batteries competitive in 

terms of both efficiency and cost. 

Nonetheless, some manufacturers stressed that a move to fast-charging, switched-mode 

power supplies and strategies typically used with lithium-ion batteries (e.g., limited maintenancemode current) would not be enough to meet CSL 2. While some claimed that this level of energy 

consumption was not achievable given today’s technology, others presented a range of advanced 

methods necessary to decrease energy consumption to equal the most efficient units currently in 

the market. 

These strategies include adaptive charge control that tailors the charge to the exact 

condition of the battery, resulting in minimal overcharge. Additionally, the power supply could 

be further improved with the addition of green-mode switching controller ICs, capable of 

reducing losses at low load, and synchronous rectification, which would reduce losses at high 

load. When used in concert, the two technologies would have the effect of flattening out the 

efficiency curve (which typically sags at low and high loads, with a peak in the middle), such 

that the BC would remain efficient over a wider range of its typical operating range. 

Nonetheless, the problem of energy consumption in the non-active modes (maintenance 

and no-battery) persists. Although green-mode controllers can reduce the energy passing through 

the transformer to the secondary side of the power supply and the charge-control stage, they 

cannot eliminate the primary-side losses due to any remaining transformer magnetization losses 

in the transformer as well as the quiescent current to the controller itself. 

To address this issue, manufacturers proposed adding a second, 1 watt power supply 

whose sole purpose would be monitoring the state of the output and input and powering the main 

power supply, as necessary. Because of its small output power, this secondary power supply 

would have minimal overhead losses, resulting in low maintenance and no-battery power for the 

charger as a whole. Short of including an entire power supply (something that has been 

implemented in practice in the case of multiple-voltage non-Class A EPSs), manufacturers also 

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proposed a monitoring circuit on the primary side that could respond to a signal from across the 

primary/secondary isolation barrier and enable the controller IC to provide current to the load. 

Again, such a circuit would result in best-in-market performance in non-active modes. Finally, as 

for CSL 1, manufacturers also mentioned the possibility of adding an electro-mechanical switch 

to detect the presence of the battery, causing disconnection of the primary in no-battery mode. 

Once the circuits have been redesigned per the above strategies, manufacturers mentioned 

that improving the parasitic resistances of line-filtering inductors and capacitors could result in 

some additional reductions in energy consumption, though compliance with emissions 

requirements could be a challenge. 

These changes could be expected to result in system-wide active-only efficiency of 

76 percent, maintenance power below 0.75 watts, and no-battery power below 0.25 watts. The 

annual energy consumption would be below 6.1 kilowatt-hours. 

5.6.10.5 CSL 3—Max-Tech 

Test and Teardown Results 

No analysis of the maximum-technologically feasible efficiency for this representative 

product class has been performed to date. 

Manufacturer Interview Results 

Again, manufacturers did not present any designs that surpassed those currently found in 

the market. Consequently, many of the manufacturer max-tech design options have been 

subsumed under the best-in market CSL, and DOE continues to search for truly max-tech 

designs. 

5.6.10.6 Estimate of Bill-of-Materials Costs 

iSuppli, a DOE contractor, tore down the four BCs corresponding to CSL 0–CSL 3 for 

this product class. iSuppli estimated the manufacturing costs (i.e., the materials, assembly, and 

test costs) of the components related to battery charging. For example, in the case of the 

notebook computer at CSL 2, iSuppli only evaluated the circuitry related to battery charging and 

supplying power to the battery charger, including battery charging components mounted to the 

computer motherboard. 

Figure 5.62 shows both manufacturer and teardown cost-efficiency curves for this 

product class. To construct the teardown curve, DOE took the cost and efficiency of the two 

units at CSL 0 and CSL 1 directly. To accommodate any remaining differences in cost between 

power tool and notebook computer BCs, DOE averaged the cost of the two most efficient units 

to arrive at a CSL 2 cost representative of both applications. The efficiency point for CSL 2 was 

that of the less efficient unit, ensuring that both units would be able to meet this CSL. These data 

are also presented in Table 5.61 Comparison of MSPs for product class 4’s representative 

unit obtained from manufacturer interviews versus those developed through teardowns. 

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$0

$3

$6

$9

$12

$15

0 10 20 30 40 50

Manufacturer Selling Price [$]

Energy Consumption [kWh/year]

Mfr Interview Data

Test and Teardown Data

CSL0

CSL1

CSL2

Figure 5.62 The efficiency related manufacturing cost of the four commercially analyzed 

BCs in this product class. 

Table 5.61 Comparison of MSPs for product class 4’s representative unit obtained from 

manufacturer interviews versus those developed through teardowns. 

MSP from MSP from 

UEC Interviews Teardowns 

CSL kWh/yr 2009$ 2009$ 

0 39.4 3.79 3.79 

1 10.5 9.52 6.76 

2 6.1 12.68 7.44 

3 - - -

5.6.10.7 Scaling of CSLs within Product Class 

Because both notebook computer and power tool manufacturers often sell accessory 

batteries of varying capacities, one possible way to determine scaling relationships for this 

product class would be to retest the units described previously in section 5.6.11.1 with larger and 

smaller replacement batteries. Similarly, some power tool BCs can charge batteries of varying 

voltages (for compatibility with multiple product lines); again tests with several batteries of 

varying voltage may lead to the development of an appropriate scaling relationship. 

5.6.11 Representative Product Class 5: Med. Energy, Low Voltage 

The medium-energy, low-voltage product class includes BCs for batteries less than 

24 volts and 100-3000 watt-hours. Batteries that meet these criteria typically have a sealed lead5-125 

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acid chemistry and are used for medium-sized motor-operated products such as lawn mowers, 

marine trolling motors, and wheelchairs. Because of the higher capacities of these batteries, 

chargers in this product class typically have much higher output powers than chargers for the 

majority of consumer products (higher energy transferred to the battery over a similar period of 

time). As a result, they employ different power converter designs (forward and half-bridge as 

opposed to flyback) than those lower-power chargers. 

Unlike the lower-energy high-volume consumer product BCs represented by the earlier 

product classes, these BCs tend to use standard-sized 6 or 12 volt lead-acid batteries, typically 

purchased separately from the BC and the end-use application. This presents two problems for 

the purposes of the analysis. 

First, because of standardization of voltages by application, batteries for wheelchairs tend 

to have a particular voltage and energy, while those for marine motors, another. Therefore, in 

contrast to earlier product classes, where the choice of battery was at the discretion of the 

manufacturer and there was a wide range of both battery voltage and energy for each application, 

it was difficult to find an overlap in terms of battery voltage and energy between the different 

applications. DOE therefore focused its representative-unit analysis solely on one application, 

namely the marine charger, though with the understanding that the analysis could be applied 

more broadly. 

Second, because the batteries are purchased separately from the BC, tests of a BC may 

produce different results depending on which battery is chosen. DOE intends to address this 

issue through its parallel BC test procedure rulemaking and welcomes suggestions from 

stakeholders. 

5.6.11.1 Units Analyzed 

DOE tested four chargers for 12 volt, sealed lead acid batteries typically used with 

scooters, wheelchairs, and marine trawling motors. Because the batteries for these applications 

vary only in terms of capacity (measured in ampere-hours), the same charger can hypothetically 

be used for any of these applications.n Therefore, where possible, DOE tested chargers in this 

product class with batteries for both wheelchair and marine applications. The results of these 

tests, as well as ones performed by Ecos Consulting, are summarized in Figure 5.63, below. 

n In practice, however, the smallest (and also least expensive) charger will be selected which can recharge a given 

battery within a required time. For example, since wheelchair batteries have a capacity around 15 ampere-hours (at 

the 5-hour rate) while marine batteries have a capacity around 60 ampere-hours, chargers for the former have a two 

to four times smaller output power and size than the latter. 

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0

5 0

100

150

200

250

300

0 200 400 600 800 1000 1200 Annual Energy Consumption [kWh]

Measured Battery Energy [Wh]

Wheelchairs

Marine Battery Charger

Ecos Tests

Rep. Unit

Efficiency Improvement Path Increasing Efficiency

Figure 5.63 Test results for representative product class 5: Medium Energy, Low Voltage. 

As can be seen in the figure, the two marine chargers that DOE selected as its teardown 

units for analysis lie in the middle of marine charger efficiency, with shipment-weighted average 

energy consumption in the range of approximately 100 to 150 kilowatt-hours per year. On the 

other hand, Ecos tests with a roughly 800 watt-hour sealed lead-acid battery resulted in a range 

of energy consumption from 65 to over 400 kilowatt-hours per year—a much wider range. 

At the high end of energy consumption, DOE purchased and examined a charger with 

similar characteristics as the inefficient one tested by Ecos, but determined that this charger was 

not suitable for testing with the sealed lead-acid batteries used for marine application, because of 

its lack of voltage control, which could lead to overcharge and damage to the battery. (The BC 

was likely intended for use with automotive starting batteries). Therefore, DOE discarded the 

results of this test as representing a suitable baseline for this product class. 

At the low end, DOE again purchased and examined chargers with similar characteristics 

as those tested by Ecos, but was unable to replicate equivalent measurements. These 

discrepancies may have been due (1) shortened tests, (2) inefficiencies in the battery used for the 

DOE tests, and/or (3) an insufficiently broad variety of chargers. 

Although the recently-proposed DOE active-mode battery charger test procedure 

specifies a 24-hour measurement period for the charge and maintenance mode tests, several of 

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the DOE tests were shortened for the sake of expediency when the battery charger was observed 

to enter a constant lower-power mode characteristic of maintenance. Nonetheless, it is possible 

that the behavior of the charger would not have stayed constant had the charger continued 

operating past this early termination, perhaps entering an even lower-power state, resulting in 

lower measured maintenance mode power. 

Secondly, an inefficient battery may have caused the lower-than-expected active mode 

efficiencies of the battery charging system. Because DOE used a different sealed lead-acid 

battery than Ecos, it is conceivable that its electrochemical charge and discharge efficiencies 

were lower, resulting in lower results for all the chargers tested. Again, how to deal with battery 

variation will be addressed in the test procedure. 

Finally, it is possible that none of the four marine chargers that DOE tested performed at 

the highest levels available in the market. Regardless of the cause of the higher-than-expected 

energy consumption of the chargers tested by DOE, additional testing and teardowns should 

resolve this issue. In the meantime, DOE has used the units it has torn down— described in 

detail in Table 5.62—to only represent the baseline and improved CSLs (CSL 0 and CSL 1). 

The remaining CSLs have been supplied by manufacturers through interviews. The typical 

performance data provided by manufacturers is listed in Table 5.63. 

Table 5.62 Detailed test results for the units corresponding to the CSLs for representative 

product class 5: Medium Energy, Low Voltage. 

CSL Application 

Battery 

Energy 

Wh 

Rated 

Battery 

Voltage 

V 

Est. 

Time in 

Active 

h 

24-Hour 

Charge 

Energy 

kWh 

Active 

Only 

System 

Eff. 

Maint. 

Power 

W 

NoBattery 

Power 

W 

UEC 

kWh/yr 

0 Marine 830.7 12.0 12.8 2.04 46% 21.2 20.1 202.7 

1 Marine 762.1 12.0 15.9 1.65 49% 11.9 11.6 159.6 

2 - - - - - - - - -

3 - - - - - - - - -

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Table 5.63 Characteristics of typical units for product class 5 described by manufacturers 

during interviews. 

CSL 

Example 

Application 

Rated 

Battery 

Energy 

Wh 

Rated 

Battery 

Voltage 

V 

Est. 

Time in 

Active 

h 

Est. 24-

Hour 

Charge 

Energy 

kWh 

Est. 

ActiveOnly 

System 

Eff. 

Est. 

Maint. 

Power 

W 

Est. NoBattery 

Power 

W 

UEC 

kWh/yr 

0 Marine 800 12 13.0 1.83 33% 10.0 10.0 202.4 

1 Marine 800 12 12.0 1.62 39% 10.0 10.0 158.4 

2 Marine 800 12 8.0 1.30 55% 0.1 0.1 100.0 

3 Marine 800 12 8.0 1.18 78% 0.0 0.0 75.0 

5.6.11.2 CSL 0—Baseline (UEC less than 202.4 kWh/yr) 

Test and Teardown Results 

The baseline marine charger tested by DOE is typical of low-cost chargers in this class, 

and is composed of a line-frequency transformer with a center-tapped secondary winding and 

two rectifier diodes. In addition, there is a small charge management circuit board with a BTW69 

silicon-controlled rectifier (SCR) in series with the DC output lead, pictured in Figure 5.64. This 

subcircuit is responsible for the linear input power characteristic evident in Figure 5.65. Finally, 

the unit contains rather small diodes in button packages, which are held against the heatsink with 

a plastic clamp. Over time, the plastic is likely to change shape decreasing the contact pressure 

between the diodes and the heatsink. While this can positively impact the efficiency of the unit 

(for a given current, the diode forward voltage decreases as the temperature rises), in the long 

run, the diodes will overheat leading to failure and a shorter lifetime. 

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(a) (b) 

Figure 5.64 Photographs of the baseline marine charger, showing (a) the line-frequency 

transformer and (b) heatsink-mounted SCR. Note the difference in size and design 

compared to the low-energy BCs. 

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Figure 5.65 Fragment of the input power waveform during charge and maintenance modes 

for the baseline unit. 

Manufacturer Interview Results 

Manufacturers did not provide information regarding the baseline efficiency. Rather, 

when developing the aggregate manufacturer response, Navigant Consulting extrapolated the 

relationship between cost and efficiency at higher CSLs down to the baseline efficiency. The 

extrapolation is explained in section 5.6.5. 

5.6.11.3 CSL 1—Improved (UEC less than 158.4 kWh/yr) 

Test and Teardown Results 

The improved (CSL 1) marine charger analyzed by DOE also features a large linefrequency transformer with a center-tapped secondary winding and two rectifier diodes. The 

large PCB, containing a microcontroller and other through-hole parts provides charge control, 

and can be adjusted using a front-panel switch depending on the type of battery (flooded or 

sealed lead-acid). 

On the whole, this charger appears much more durable than the baseline unit, with a 

heavy conformal coating on the board (increasing the longevity of the unit in damp and dirty 

environments) and a heavier-than-usual aluminum bracket, which serves as a heatsink for the 

diodes. 

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` 

(a) (b) 

Figure 5.66 Photographs of the improved marine charger, showing (a) the line-frequency 

transformer and (b) complex charge-control PCB. 

Despite providing the additional functionality of charging two battery types, this unit 

performs better than the baseline, charging the battery in less time with fewer losses. The input 

power characteristic of the improved unit in active and maintenance modes is presented in 

Figure 5.67. 

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0 

50 

100 

150 

200 

250 

0:00:00 6:00:00 12:00:00 

Input Power [W] 

Test Time [h] 

Figure 5.67Fragment of the input power waveform during charge and maintenance modes 

for the CSL 1 unit. 

Manufacturer Interview Results 

Again, manufacturers did not provide information regarding the improved efficiency, 

resulting in a manufacturer-derived relationship that is a continuation of that found at the higher 

CSLs. 

5.6.11.4 CSL 2—Best-in-Market (UEC less than 100 kWh/yr) 

Test and Teardown Results 

DOE did not tear down any more efficient medium-energy, low voltage chargers beyond 

the two described in Section 5.6.11.2 and 5.6.11.3, above. Nonetheless, DOE would expect that 

charge management could reduce power consumption at end of charge. Since chargers in this 

product class spend large amounts of time in maintenance mode, such improvements could result 

in significant annual energy savings. 

Manufacturer Interview Results 

To meet the best-in-market CSL, manufacturers suggested using a silicon-controlled 

rectifier (SCR) charger with a best-in-class line-frequency transformer, which can be up to 50% 

more expensive than that used at CSL 1. In addition to transformer improvements, manufacturers 

suggested using the SCRs to perform both rectification and control by placing them directly in 

the center-tapped half-wave rectifier; or if using a full-wave bridge rectifier, replacing the silicon 

pn-junction diodes with Schottkies. 

Alternatively, manufacturers also suggested foregoing the SCR topology entirely, in 

favor of a high-frequency switched-mode design, which has the added benefit of lighter weight 

due to smaller transformer size. Finally, to completely eliminate energy consumption in 

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maintenance and no-battery modes, manufacturers suggested including a relay to disconnect the 

primary side of the battery charger from mains. A typical manufacturer unit at CSL 2 had a 

system-wide active-only efficiency of more than 55 percent, maintenance power of 0.1 watts, 

and no-battery power of 0.1 watts, for an annual energy consumption lower than 100 kilowatthours. 

5.6.11.5 CSL 3—Max-Tech (UEC less than 75 kWh/yr) 

Test and Teardown Results 

No analysis of the maximum-technologically feasible efficiency for this representative 

product class has been performed to date. 

Manufacturer Interview Results 

To achieve the maximum technologically feasible efficiency, resulting in an annual 

energy consumption of less than 10 kilowatt-hours, manufacturers did not propose any novel 

topologies. Instead they provided incremental improvements to the SCR and switched-mode 

topologies developed for CSL 2, above. 

Since, as described above in section above, non-active energy consumption in 

maintenance and no-battery modes could be eliminated entirely for some application through the 

use of a relay, manufacturers focused on further reducing the energy consumption in active mode 

to meet CSL 3. These could be achieved by increasing the efficiency of the transformer through 

further investment in core steel (reducing magnetization losses) and winding copper (reducing 

resistive conduction losses). Similar reductions in resistive losses could be made throughout the 

rest of the charger by the widths of the conductive traces on the PCB or the gauge of the 

connecting cables. 

These improvements could result in a system-wide active-only efficiency approaching 

80 percent (above 90 percent, excluding the battery), maintenance and no-battery power at 

0 watts, and annual energy consumption below 10 kilowatt-hours. 

5.6.11.6 Estimate of Manufacturer Selling Price 

As before, iSuppli, a DOE contractor, tore down the two BCs at CSL0 and CSL 1 for this 

product class, and estimated the cost of the electronic components. These were subsequently 

marked up to reflect manufacturers costs, resulting in the partial teardown curve in Figure 5.68. 

The figure also shows the aggregated manufacturer MSPs. Although manufacturers provided 

costs only at CSL 2 and CSL 3, the cost-efficiency relationship they developed was extrapolated 

to the lower CSLs, where it corresponded will with the teardown results. The detailed results for 

both manufacturers and teardowns are presented in Table 5.64. 

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$15

$30

$45

$60

$75

$90

$105

$120

$135

$150

50 100 150 200 250

Manufacturer Selling Price [$]

Energy Consumption [kWh/year]

Mfr Interview Data

Test and Teardown Data

CSL1 CSL0

CSL2

CSL3

Figure 5.68 Cost-efficiency results at each CSL for representative unit 5. 

Table 5.64 Comparison of MSPs for product class 5’s representative unit obtained from 

manufacturer interviews versus those developed through teardowns. 

MSP from MSP from 

UEC Interviews Teardowns 

CSL kWh/yr 2009$ 2009$ 

0 202.7 18.48 18.48 

1 159.6 27.46 21.71 

2 100.0 64.14 -

3 75.0 127.00 -

5.6.11.7 Scaling of CSLs within Product Class 

Because chargers in this product class are sold independently from the battery, they can 

be tested with a variety of batteries of different capacities. By retesting the units discussed above 

using different batteries, as well as testing additional units, appropriate scaling relationships can 

be developed. 

5.6.12 Representative Product Class 7: High Energy 

The high-energy representative product class includes BCs for batteries with an energy 

greater than 3000 watt-hours. Whereas the BCs included in product class 6 were intended to 

charge batteries for a variety of applications, the high-energy batteries associated with chargers 

in product class 7 are only used for golf cars and utility vehicles. Furthermore, these high-energy 

batteries use a flooded or wet lead-acid construction, meaning that the batteries are free to vent to 

the outside air in case of excessive gas buildup. Although this requires additional care in 

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handling (e.g., the batteries should not be tipped or left exposed to the elements), it does make 

the batteries more resilient to overcharge and results in looser tolerances (and lower costs per 

watt of output power) on the chargers. These differences led DOE to place these chargers in a 

separate product class, though some manufacturers claimed there was broad similarity between 

all chargers for medium and high energy batteries. DOE requests input on its decision to 

separate these two product classes despite manufacturer comments suggesting that it may not be 

necessary. 

5.6.12.1 Units Analyzed 

Because of the high energy of golf car batteries compared to those for other consumer 

products, DOE had difficulty performing the necessary tests and teardowns for inclusion in the 

preliminary analysis. Therefore, DOE relied on manufacturer interviews to create a costefficiency relationship for this product class. Performance figures typical of those presented by 

manufacturers for units meeting each CSL are shown in Table 5.65. 

Table 5.65 Characteristics of typical units for product class 7 described by manufacturers 

during interviews. 

CSL 

Example 

Application 

Rated 

Battery 

Energy 

Wh 

Rated 

Battery 

Voltage 

V 

Est. 

Time in 

Active 

h 

Est. 24-

Hour 

Charge 

Energy 

kWh 

Est.-

Active 

Only 

System 

Eff. 

Est. 

Maint. 

Power 

W 

Est. 

NoBattery 

Power 

W 

UEC 

kWh/yr 

0 Golf Car 3750 48 8.0 5.90 64% 3.6 3.7 290.0 

1 Golf Car 3750 48 8.0 5.61 68% 3.3 3.2 250.0 

2 Golf Car 3750 48 8.0 5.24 72% 2.9 2.6 200.0 

3 Golf Car 3750 48 8.0 4.86 78% 2.6 2.0 150.0 

* Note that the battery energy is measured over a 5-hour discharge, in accordance with the proposed BC test 

procedure. 

5.6.12.2 CSL 0—Baseline (UEC less than 290 kWh/yr) 

Manufacturer Interview Results 

Baseline golf car chargers use ferro-resonant (FR) or silicon-controlled rectifier (SCR) 

topologies, though FR is falling out of favor because of recent increases in the cost of the highgrade steel due to competition with the global electricity transmission and distribution industry. 

According to manufactures, the cost of an FR transformer can be up to 80 percent of the cost of 

the charger, such that these swings in materials prices directly impact the manufacturer selling 

price of the charger, causing a shift toward SCR. 

In either case, the chargers use standard silicon pn-junction diodes for rectification, 

resulting in charger-only (i.e., excluding any losses in the battery) active mode efficiencies of 

approximately 80 percent. Manufacturers differed regarding the prevalence of energy 

improvements intended to reduce energy consumption in the non-active modes. Although some 

of the chargers described had no-battery and maintenance power greater than 5 watts, others used 

relays that cut off power to the primary after the charge has finished, interrupting the flow to the 

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battery and resulting in an input power of 0 watts in maintenance and no-battery modes. The 

annual energy consumption for a baseline BC in this product class is less than 290 kilowatthours. 

5.6.12.3 CSL 1—Improved (UEC less than 250 kWh/yr) 

Manufacturer Interview Results 

To reduce the energy consumption of the chargers in active mode with the goal of 

reaching CSL 1, manufacturers suggested either incremental improvements or a wholesale 

redesign of the BC to take advantage of a switched-mode topology. 

Potential incremental improvements involved the substitution of Schottky diodes, which 

have half the forward voltage drop of conventional diodes, in the bridge rectifier. Although 

further incremental improvements could be made, the more cost-effective alternative would be a 

redesign of the charger for one with a high-frequency switched mode power supply. The benefits 

of such a change include not only higher efficiency, but also lower weight, higher power factor, 

and usability across a wider range of input voltages. 

While the Schottkies are likely to increase the active-mode efficiency by 1 percentage 

point, the move to a switched-mode topology provides a significant increase in efficiency, by 

around 5 percentage points, resulting in charger-only efficiencies around 85 percent. Input power 

in maintenance and no-battery modes still depends on the manufacturers’ willingness to install a 

relay. Regardless of which design options are implemented, the annual energy consumption is 

less than 250 kilowatt-hours. 

5.6.12.4 CSL 2—Best-in-Market (UEC less than 200 kWh/yr) 

Manufacturer Interview Results 

Meeting the best-in-market CSL would require a transition to a switched-mode topology, 

with charger-only active-mode efficiency above 85 percent and input power in maintenance and 

no-battery modes below 3 watts. As mentioned above, switched-mode topologies may have some 

additional utility advantages over the baseline and improved SCR chargers, and as long as the 

maintenance and no-battery power is reduced, they may meet CSL 2 with annual energy 

consumption below 200 kilowatt-hours. 

5.6.12.5 CSL 3—Max-Tech (UEC less than 150 kWh/yr) 

Finally, manufacturers also speculated on ways of further reducing the energy 

consumption of current best-in-market units, though, according to manufacturers, no further 

improvements in topology exist, with additional incremental improvements offering diminishing 

returns. 

Manufacturers first proposed increasing the widths of all conductors in the battery 

charger as a way of reducing resistive losses, similarly to the methods in product class 5, 

described in section 5.6.11.5. These conductors include the PCB traces, the cables connecting the 

charger to the battery, and the transformer windings. However, these improvements have 

limitations: space inside the charger is limited and wires with a thicker gauge will be bulkier and 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

less flexible. Furthermore, wider wires in the transformer will push the windings away from the 

core. The resultant spacing will cause more magnetic flux to leak away from the transformer and 

reduce the coupling from the primary to the secondary winding, counteracting any improvement 

in efficiency due to lower resistance. At best, such improvements could result in a charger-only 

active-mode efficiency slightly above 90 percent. 

Further improvements would include upgrades to the magnetic components (including 

the transformer cores), replacing diodes with FETs (synchronous rectification), and finally 

decreasing the losses of the FETs, in order of increasing costs. Such techniques could increase 

the active-mode efficiency to around 95 percent in active mode (excluding the battery), though at 

very high cost. These changes, however, would be necessary to decrease the annual energy 

consumption below 150 kilowatt-hours. 

5.6.12.6 Estimate of Manufacturer Selling Price 

As mentioned above, DOE did not perform teardowns of units in this product class; therefore, 

Figure 5.69 shows only the manufacturer cost-efficiency curve shown at each CSL. Detailed 

cost information is also presented in Table 5.66. 

$0

$25

$50

$75

$100

$125

$150

$175

$200

$225

$250

100 150 200 250 300 350

Manufacturer Selling Price [$]

Energy Consumption [kWh/year]

Mfr Interview Data

CSL0

CSL1

CSL2

CSL3

Figure 5.69 Manufacturer cost efficiency relationship for representative unit 7. 

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Table 5.66 Comparison of MSPs for product class 7’s representative unit obtained from 

manufacturer interviews versus those developed through teardowns. 

MSP from MSP from 

UEC Interviews Teardowns 

CSL kWh/yr 2009$ 2009$ 

0 290 79.01 -

1 250 94.94 -

2 200 127.05 -

3 150 192.32 -

5.6.12.7 Scaling of CSLs within Product Class 

Although the propulsion systems of golf cars (the dominant application in this product 

class) can differ between manufacturers, requiring different battery voltages and capacities, these 

differences (36 versus 48 volts and 200 versus 150 ampere-hours, at the 20-hour rateo

) should not 

substantially impact the achievable efficiencies or cost. Basically, the power levels in this 

product class are so high that the fixed losses are unlikely to have a differential impact on the 

performance of a BC charging a 36 volt, 200 ampere-hour battery versus a 48 volt, 150 amperehour battery. 

DOE therefore does not expect to scale the CSLs throughout this product class, and is 

considering using a flat standard level applicable to all units, equal to the CSLs presented in 

Table 5.66. 

5.6.13 Representative Product Class 10: Low Energy, AC Output 

The final product class analyzed includes BCs that are a part of uninterruptible power 

supplies (UPSs). UPSs are battery-operated products that provide backup power to other 

electronic products in case of a power outage. As such, they differ from other BC products in 

that they are never used except in case of emergency and have additional circuitry downstream 

of the battery (an inverter) to provide AC output to the electronic appliances protected. 

Navigant Consulting specifically interviewed manufacturers of uninterruptible power 

supplies to determine the impact of the inverter and other specialized circuitry on the costefficiency relationship of BCs for these applications. The results of these interviews, as well as 

product tests and teardowns, are summarized in the sections below. 

5.6.13.1 Units Analyzed 

DOE purchased five UPSs from an online retailer for testing and possible teardowns. 

Like transformers and other power-electronic components, UPSs are rated in terms of maximum 

o Lead-acid battery capacity is typically advertised at the 20-hour rate. Because of current-dependent losses and 

dynamic behavior in the battery, the actual capacity will be lower when measured at a 5-hour rate (consistent with 

the proposed BC test procedure), lower still at the 2–3 hour rate (the typical rate of discharge during use). 

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EERE-2008-BT-STD-0005 COMMENT 31
 

volt-ampere (VA) output, which is a measure of total power (both real and reactive) they can 

provide, and is equal to the maximum power drawn by a load divided by its minimum power 

factor. Four of the five units had output between 500 and 650 volt-amperes, which manufacturers 

later confirmed was a popular range within their consumer/small business product lines. Two of 

the units—one at 250 volt-amperes and another at 550 volt-amperes—were not included in the 

further analysis because they provided additional functionality, described below, that inflated the 

apparent battery charger energy consumption and confounded the comparison of cost and 

efficiency. All these units used 12-volt valve-regulated lead-acid (VRLA) batteries with a rated 

capacity of 7 to 9 ampere-hours (at the 20-hour rate). This battery configuration is, again, typical 

of UPSs used by consumers. 

These units were tested according to the proposed DOE test procedure. As was the case 

for the other product classes, the per-mode measurements obtained using the test procedure were 

then weighted according to the usage profile to obtain an annual energy consumption. In the case 

of UPSs, which spend the vast majority of their time in maintenance mode, this simply involved 

multiplying the maintenance power by number of hours per year (8760). 

The results of testing and weighting appear in Figure 5.70, which compares DOE results 

with those conducted by Ecos Consulting. Unlike in many of the other product classes analyzed, 

the battery characteristics should not significantly impact the energy consumption of UPS BCs, 

as maintenance mode power—which is largely independent of the battery characteristics—is the 

only metric that contributes to annual energy consumption. 

0

50

100

150

200

250

0 50 100 150 200

Annual Energy Consumption [kWh]

Measured Battery Energy [Wh]

Uninteruptible Power Supplies

Ecos Tests

Rep. Unit

Efficiency Improvement Path

Increasing Efficiency

Figure 5.70 Test results for the low-energy, AC-output representative product class. 

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Instead, any differences in energy consumption appear to be the result of charger design 

or additional functionality. Note, for instance, the least efficient UPS tested by DOE, with an 

annual energy consumption of approximately 180 kilowatt-hours. This corresponds to over 

20 watts in maintenance mode, but is not due to any gross inefficiencies in the charger, but rather 

to line voltage regulation, which conditions the power delivered to the load by passing it through 

the battery. 

The same applies to the DOE-tested unit with an annual energy consumption of 

approximately 65 kilowatt-hours, which also adjusts to variations in the input voltage. The highannual energy consumption Ecos units at the top of the plot are assumed to provide similar 

additional functionality. 

As such, it is difficult to separate the energy consumption required for battery charging 

and maintenance from that due to device operation. The situation is analogous to trying to 

measure the energy consumption of a BC for a notebook computer with the notebook computer 

turned on and operational. Furthermore, unlike in a notebook computer, the charging and power 

conditioning functions may not be separable—i.e., turning off the unit may also disconnect the 

power provided to the battery. These units were therefore excluded from further analysis—until 

DOE finalizes how it intends to address products with additional functionality in its proposed 

battery charger test procedure. 

Of the remaining UPSs tested, two were selected for further analysis. The test results for 

these are listed in Table 5.67, while specific design options for these UPSs are described in the 

sections that follow. As before, Navigant Consulting, a DOE contractor, also interviewed 

manufacturers of UPSs to gain further insight on the cost-efficiency relationship. The interviews 

proved particularly informative because of the integration of the BC into the end-use product in 

this product class; the manufacturers provided further insight into the impact of the inverter and 

other specialized circuitry on the cost-efficiency relationship of these BCs. The typical 

performance of units at each CSL as reported by manufactures is presented in Table 5.68, while 

further discussion is presented in the sections below. 

Table 5.67 Detailed test results for the units corresponding to the CSLs for product class 

10: Low-Energy AC Output. 

CSL Application 

Battery 

Energy 

Wh 

Rated 

Battery 

Voltage 

V 

Est. 

Time in 

Active 

h 

24-Hour 

Charge 

Energy 

Wh 

ActiveOnly 

System 

Eff. 

Maint. 

Power 

W 

NoBattery 

Power 

W 

UEC 

kWh/yr 

0 UPS 78.0 12.0 24.0 149.9 42% 2.2 - 19.6 

1 UPS 51.7 12.0 17.3 93.0 44% 0.7 - 6.4 

2 - - - - - - - - -

3 - - - - - - - - -

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Table 5.68 Characteristics of typical units for product class 10 described by manufacturers 

during interviews. 

CSL 

Example 

Application 

Rated 

Battery 

Energy 

Wh 

Rated 

Battery 

Voltage 

V 

Est. 

Time in 

Active 

h 

Est. 24-

Hour 

Charge 

Energy 

Wh 

Est. 

ActiveOnly 

System 

Eff. 

Est. 

Maint. 

Power 

W 

Est. 

NoBattery 

Power 

W 

UEC 

kWh/yr 

0 UPS 70 12 24.0 0 24% 2.2 - 19.6 

1 UPS 70 12 24.0 0 50% 0.7 - 6.4 

2 UPS 70 12 24.0 0 62% 0.5 - 4.0 

3 UPS 70 12 24.0 0 84% 0.2 - 1.5 

5.6.13.2 CSL 0—Baseline (UEC less than 19.6 kWh/yr) 

Test and Teardown Results 

DOE disqualified two UPS from further analysis as their relatively high energy 

consumption was likely due to additional functionality (power conditioning) unrelated to battery 

charging and it selected the next best-performing UPS as its baseline unit for analysis. 

The input power waveform for this charger during active and maintenance modes is 

pictured in Figure 5.71, and shows the constant-current, constant-voltage characteristic typical 

of lead-acid battery chargers.p The resultant efficiency is approximately 42 percent, including 

losses in the battery, and it is made possible by a more efficient switched-mode power supply. 

The resultant annual energy consumption of this unit is 19.6 kilowatt-hours. 

p During the first (flat) part of the curve, the charger provides a fixed current. The input power nonetheless increases 

because battery voltage is increasing as the battery charges, and the power to the battery (to the input power). The 

second portion sees the charger maintaining a constant voltage across the battery, with exponentially decreasing 

charge current, and, consequently, input power. 

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Figure 5.71 Input power waveform during charge and maintenance modes for the CSL 1 

unit. 

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Figure 5.72 Photograph of the PCB of the baseline unit for this product class. The BC 

circuitry is mainly to the left. 

Manufacturer Interview Results 

The baseline CSL corresponds to the lowest efficiency UPS tested by DOE, except for 

those that performed power conditioning and therefore consumed power in excess of that 

required for battery charging and any mainstream UPS functions. According to manufacturers, 

this level can be met by a variety of charger designs, including a fairly inefficient line-frequency 

charger with charger-only active-mode efficiency less than 50 percent. Since for the majority of 

U.S. consumers power outages are rare, BCs for UPSs seldom operate in active mode. Therefore, 

the active mode efficiency does not impact the BC’s annual energy consumption. Furthermore, 

since the battery is internal and the AC line cord attaches directly to the UPS (such that no 

component of the BC can remain connected to the line), the no-battery mode is not applicable to 

this product class. Therefore, the only metric influencing annual energy consumption is input 

power during maintenance mode. 

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According to the interviews, typical input power during maintenance mode for linefrequency BCs is approximately 2 watts, due to typical linear converter standby losses such as 

magnetization losses in the transformer or leakage in the bulk capacitor. The parasitic losses in 

the transformer windings, which are used to control charge current to the battery, also play a 

role. 

Additional losses specific to the UPS, and which cannot be disabled, include the power 

draw of a microcontroller that monitors not only the battery charging, but also the state of the AC 

line and communications and control lines connected to a personal computer (the typical 

electronic product connected to such a UPS). The result is an annual energy consumption of less 

than 19.6 kilowatt-hours. 

5.6.13.3 CSL 1—Improved (UEC less than 6.4 kWh/yr) 

Test and Teardown Results 

The improved teardown unit shows an even shorter charge time and lower active mode 

power than the baseline, though those performance characteristics vary with battery size. (See 

Figure 5.73) What does not vary, and ultimately determines the UPS’s annual energy 

consumption is maintenance mode power, which is very low (0.7 watts according to Table 5.67). 

This low power is enabled by a switched-mode power supply, which not only has synchronous 

rectification (paired transistors mounted to heatsinks on the secondary side of the power supply), 

but also a low-power controller IC, with one third the quiescent current of the IC used in the 

CSL 0 unit. The annual energy consumption of this BC is 6.4 kilowatt hours. 

Figure 5.73 Input power waveform during charge and maintenance modes for the CSL 1 

unit. 

Manufacturer Interview Results 

More efficient UPSs use a switched-mode topology as the input stage to the charger. The 

switched-mode chargers have a similar cost as the line-frequency chargers meeting the baseline 

CSL, but higher active-mode efficiency, typically higher than 85 percent. 

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However, as before, it is the maintenance mode power that impacts the energy 

consumption of BCs for this application. The switched-mode charger, because it operates at a 

much higher frequency, can use a smaller transformer, with consequently lower magnetization 

losses. Overhead losses due to line monitoring and microcontroller operation can be further 

reduced, resulting in a maintenance mode power less than 0.75 watt, resulting in annual energy 

consumption less than 6.4 kilowatt-hours. 

5.6.13.4 CSL 2— Best-in-Market (UEC less than 4 kWh/yr) 

Test and Teardown Results 

No analysis of the best-in-market efficiency for this representative product class has been 

performed to date. 

Manufacturer Interview Results 

Although DOE was unable to identify any UPSs with annual energy consumption below 

6.4 kilowatt-hours (the CSL 1 level), manufacturers indicated that incremental improvements can 

decrease the energy consumption of the BC. In particular, energy-efficient power controller ICs 

and improved FETs can be used to increase active-mode conversion efficiency of the BC to 

greater than 80 percent (for a system-wide active-only efficiency above 65 percent). 

Improvements to the microcontroller (typically used to control the charging process as well as 

other aspects of the operation of the UPS) can also further decrease energy consumption in 

maintenance below 0.5 watts. Together, these changes can reduce the annual energy 

consumption below 4 kilowatt-hours. 

5.6.13.5 CSL 3—Max-Tech (UEC less than 1.5 kWh/yr) 

Test and Teardown Results 

No analysis of the maximum-technologically feasible efficiency for this representative 

product class has been performed to date. 

Manufacturer Interview Results 

Finally, manufacturers speculated on further methods of decreasing the energy 

consumption of these BCs beyond what is currently available in the market. Although higherefficiency switching converters for active-mode efficiency are available, they will not be 

effectual in further reducing the annual energy consumption of the BC. 

As in the other product classes, high-efficiency switched-mode controller ICs that 

decrease energy consumption at low-load are a potential means of reducing maintenance power. 

However, manufacturers also speculated on ways to completely disable the primary side of the 

switched-mode power converter that is the first stage of the BC. By running from the integral 

battery, the on-board microcontroller could completely shut down the input stage, enabling it 

only when the battery had discharged past a desirable level or some external condition (such as 

input voltage variation or communication with a personal computer) warrants. 

According to manufacturers, such a strategy could result in maintenance mode power 

below 0.17 watts, resulting in a max-tech UEC of 1.5 kilowatt-hours. 

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5.6.13.6 Estimate of Manufacturer Selling Price 

The results of iSuppli teardowns as well as aggregated manufacturer interviews, appear in 

Figure 5.74. As mentioned above in section 5.6.13.2, teardown analysis revealed that the 

baseline unit, despite its active mode inefficiency and high maintenance mode energy 

consumption commanded a higher price than that at CSL 1. Again, DOE is concerned that this 

unit’s high energy consumption is due to some additional functionality that DOE did not take 

into account, and seeks comment on the cost and efficiency of the baseline unit in this class. 

Manufacturer selling price was calculated across all CSLs, even though manufacturers only 

provided data for CSL 2 and CSL 3. Both sets of data are detailed in Table 5.69, below. 

$2.0

$2.5

$3.0

$3.5

$4.0

$4.5

$5.0

0 5 10 15 20 25

Manufacturer Selling Price [$]

Energy Consumption [kWh/year]

Mfr Interview Data

Test and Teardown Data

CSL0

CSL1

CSL2

CSL3

Figure 5.74 Teardown and interview MSPs at each CSL for representative unit 10. 

Table 5.69 Comparison of MSPs for product class 10’s representative unit obtained from 

manufacturer interviews versus those developed through teardowns. 

MSP from MSP from 

UEC Interviews Teardowns 

CSL kWh/yr 2009$ 2009$ 

0 19.6 2.76 2.76 

1 6.4 3.93 2.11 

2 4.0 4.25 -

3 1.5 4.64 -

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5.6.13.7 Scaling of CSLs within Product Class 

The market assessment and interviews with manufacturers revealed that uninterruptable 

power supplies are the only applications covered by this product class. As discussed, the vast 

majority of UPSs run entirely in maintenance mode and power consumption in this mode is 

largely independent of the voltage and energy characteristics of the batteries. Additionally, DOE 

believes that those units with excessive energy consumption as seen in DOE’s (and ECOS’s) test 

results were because of added functionality provided by those UPSs. Therefore, DOE does not 

intend to perform any scaling within this product class. 

5.6.14 Extending the Analysis to Product Classes not Analyzed Directly 

DOE focused its engineering analysis on the representative product classes—product 

classes with the highest number of shipments or the highest estimated energy consumption, 

according to initial estimates based on the market survey. Nonetheless, there are still significant 

shipments, and consequently, potential for energy savings, in the non-representative product 

classes. The sections below describe how DOE extended the engineering analysis to these 

product classes to evaluate the impact of potential standards. 

For EPSs, DOE was able to directly model the cost-efficiency relationship for scaled 

product classes using the curves developed for the representative product class. For BCs, 

however, the cost-efficiency curves for each representative unit are functions of UEC and take 

into account the usage profiles (described further in chapter 7) for the applications in that 

representative product class. Therefore, DOE could not simply scale the BC cost-efficiency 

results presented in section 5.6.8 through 5.6.13; rather, DOE had to scale and then re-weight 

(according to the new usage profile) the per-mode data obtained through testing and 

manufacturer interviews. 

In section 5.6.7, above, DOE discussed some potential strategies for scaling the results of 

the representative-unit analysis to units not analyzed directly, using engineering relationships or 

data available in the market. Pending comment from interested parties on the applicability of the 

listed methods, DOE used a simpler approach for the analysis of the scaled product classes. In 

short, DOE assumed that the efficiency of the BCs tested or described by manufacturers would 

not change—rather, any changes in annual energy consumption would be due to the difference in 

battery energy and usage between product classesq

. 

Thus, for example, when scaling the performance of a notebook computer BC for use 

with scaled product class 3, DOE maintained the same charge time, active mode efficiency, 

maintenance mode, no-battery mode, and off mode power, but now applied those to charging a 

battery typical of BCs in that product class (e.g., those used with a portable DVD player). Since 

the maintenance mode, no-battery mode, and off mode power were constant, only the energy lost 

per charge would change. 

q For clarity, when it is stated that DOE performed an analysis it should be noted that Navigant Consulting handled 

all sensitive information gleaned from manufacturer interviews. 

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Subsequently, these per-mode energy consumption metrics were weighted by the usage 

profile of the scaled product class. Therefore, even though there may have been no great changes 

in the per-mode energy consumption, the annual energy consumption may have changed 

significantly due to differences in usage. 

The detailed methodology and results for each representative product class are presented 

in the sections that follow. 

5.6.14.1 Scaled Product Class 3: Low Energy, Medium Voltage 

This product class spans the gap between the low energy, low voltage and low energy, 

high voltage product classes (i.e., BC product classes 2 and 4), which each have higher 

shipments. Nonetheless, the applications in this product class are fairly similar to those in the 

other two product classes: power tools, handheld vacuum cleaners, two-way radios, and portable 

DVD players. The BC design is also similar to that of the other two product classes, consisting of 

multi-cell nickel chargers (both fast and slow) and fast lithium-ion chargers. 

The lithium-ion batteries used with chargers in this product class are multi-cell, like those 

in product class 4. However, evaluations of several DVD players revealed none of the 

complexities common to the design of the higher-voltage notebook computer batteries; rather, 

they were more similar to the single-cell lithium-ion batteries for cellular phones and portable 

media players. The most efficient BCs in the market for portable DVD players can also achieve 

energy consumption as low as some of the low energy, low voltage units. Despite these 

similarities in BC design, the usage in product class 3 was much lighter than in either of the 

representative product classes, as can be seen in Table 5.68. 

Table 5.70 BC Shipments-Weighted Average Usage Profiles for Product Classes 2, 3, and 4 

BC Product 

Class 

Active + 

Maintenance 

No Battery 

(Standby) Unplugged Off Charges 

Hours per Day Number per 

Day 

2 9.7 5.0 9.4 0 0.58 

3 5.6 0.2 18.1 0.1 0.22 

4 16.8 0.3 6.9 0.1 0.88 

Note: Usage times may not sum to exactly 24 hours due to rounding. 

Because the products in this class are an amalgam of those in product classes 2 and 4, 

DOE used the manufacturer cost-efficiency data for those representative product classes to 

develop the cost-efficiency relationship for product class 3. As described above, Navigant first 

scaled the energy loss per charge to account for the difference in battery energy between product 

classes 2 and 4, and 3; then, Navigant Consulting applied the usage profile for product class 3 to 

calculate the annual energy consumption of the manufacturer designs for product classes 2 and 4 

when used with applications in product class 3. Nonetheless, DOE seeks comment on alternative 

methods of determining costs and efficiencies for the low energy, medium voltage product class. 

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The baseline CSL for this product class was based on the lowest-performing results 

provided by manufacturers, scaled to reflect the battery and usage of product class 3. CSLs 1 

and 2 were based on the results of tests of BCs in product class 3 performed by DOE and Ecos 

Consulting, again weighted to reflect typical use for product class 3. Since DOE did not tear 

down any products in the scaled product classes, all costs are interpolations of the scaled 

manufacturer cost-efficiency data. The results are summarized in Table 5.71 and Table 5.72 . 

Table 5.71 Characteristics of typical units scaled for product class 3. 

CSL 

Example 

Application 

Rated 

Battery 

Energy 

Wh 

Rated 

Battery 

Voltage 

V 

Est. 

Time in 

Active 

h 

Est. 24-

Hour 

Charge 

Energy 

Wh 

Est. 

ActiveOnly 

System 

Eff. 

Est. 

Maint. 

Power 

W 

Est. 

NoBattery 

Power 

W 

UEC 

kWh/yr 

0 Power Tool 10 7.2 16.1 91.3 19% 4.7 1.0 10.0 

1 Cell Phone 10 7.2 10.3 65.7 32% 2.5 0.6 5.4 

2 Cell Phone 10 7.2 1.1 21.4 60% 0.2 0.2 1.0 

3 - - - - - - - - -

Table 5.72 Resulting cost and efficiency relationship for BC product class 3. 

MSP from MSP from 

UEC Interviews Teardowns 

CSL kWh/yr 2009$ 2009$ 

0 10.0 $3.16 -

1 5.4 $4.96 -

2 1.0 $12.99 -

3 - - -

5.6.14.2 Scaled Product Class 6: Medium Energy, High Voltage 

This product class is similar to product class 5: medium energy, low voltage. BCs in this 

product also charge sealed lead-acid batteries, though for a different set of applications. Because 

of the general similarities between chargers at the higher battery energies, DOE used the costefficiency data obtained from manufacturers for product class 5, scaled according to the typical 

battery energy and voltage of product class 6, and weighted by the usage profiles of product class 

6 applications, such as lawnmowers and electric bicycles. 

DOE based the baseline and improved CSLs (CSL 0 and 1) for this scaled product class 

on the results of tests conducted on BCs in this class. In particular, DOE tested four lawnmower 

BCs with a 408 watt-hour, 24 volt sealed lead-acid battery, and set the baseline to the UEC of the 

worst-performing unit. Two of the other units reached an annual energy consumption of 

approximately 40 kilowatt-hours, so DOE set the improved CSL at that level. The remaining two 

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CSLs (CSL 2 and 3) were based on the performance of manufacturer designs from representative 

product class 5, scaled to the battery and usage of product class 6. Finally, the MSP was 

calculated at each CSL by using the best-fit curve through the manufacturer data. The results are 

summarized in Table 5.73 and Table 5.74. 

Table 5.73 Characteristics of typical units scaled for product class 6. 

CSL 

Example 

Application 

Rated 

Battery 

Energy 

Wh 

Rated 

Battery 

Voltage 

V 

Est. 

Time in 

Active 

h 

Est. 24-

Hour 

Charge 

Energy 

Wh 

Est. 

ActiveOnly 

System 

Eff. 

Est. 

Maint. 

Power 

W 

Est. 

NoBattery 

Power 

W 

UEC 

kWh/yr 

0 Marine 384 36 20.0 720.8 55% 5.0 1.2 69.3 

1 Marine 384 36 16.0 620.0 62% 0.5 0.5 41.9 

2 Marine 384 36 16.0 524.6 74% 0.3 0.3 25.0 

3 Marine 384 36 8.0 491.3 78% 0.0 0.0 18.0 

Table 5.74 Resulting cost and efficiency relationship for BC product class 6. 

MSP from MSP from 

UEC Interviews Teardowns 

CSL kWh/yr 2009$ 2009$ 

0 69.3 $18.48 -

1 41.9 $35.87 -

2 25.0 $76.83 -

3 18.0 $139.95 -

5.6.14.3 Scaled Product Class 8: Low Energy, 5 V DC Input 

This product class contains small consumer electronic products typically recharged using 

the 5 volt output of a computer’s USB port, in particular portable media players and personal 

data assistants (PDAs). Interviews with manufacturers revealed that the BCs in this product class 

are similar to those in representative product class 2, which are typically used with cellular 

telephones, except that they do not require an EPS. 

Therefore, to develop a cost-efficiency relationship for this product class, Navigant 

Consulting subtracted out the typical EPS losses and costs at each CSL. To model these 

quantities, Navigant Consulting used the EPS results for the 2.5 watt EPS, originally presented in 

Table 5.29 and reproduced in part in Table 5.75 below. 

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Table 5.75 Cost and Efficiency Relationship for 2.5W EPS (Manufacturer Interviews) 

CSL 0 CSL 1 CSL 2 CSL 3 

Mfr Unit Efficiency [%]: 

Mfr Unit No Load Power [W]: 

MSP Difference with CSL0 [$]: 

58.3% 

0.500 

$0.00 

67.9% 

0.300 

$0.05 

73.5% 

0.100 

$0.26 

74.0% 

0.053 

$0.32 

To model the change in BC energy consumption without the presence of an EPS, such as 

the one above, Navigant Consulting divided the active-mode efficiency provided by the 

manufacturers at each CSL by the EPS efficiency. Similarly, Navigant Consulting subtracted 

from the maintenance mode power and the no-battery mode power the EPS no-load power. Next, 

Navigant Consulting subtracted out the incremental cost difference from the BC MSP so as to 

eliminate the cost impact of improving the EPS on the BC MSP. Then, as above, Navigant 

Consulting scaled product class 2, scaling the charging losses to account for any difference in 

battery energy and re-weighting the performance in each mode by the average usage profile of 

the applications in this product class. 

The CSLs for this product class were based on some DOE tests and the distribution of the 

scaled manufacturer data. The results are presented in below Table 5.74 and Table 5.77. 

Table 5.76 Characteristics of typical units scaled for product class 8. 

CSL 

Example 

Application 

Rated 

Battery 

Energy 

Wh 

Rated 

Battery 

Voltage 

V 

Est. 

Time in 

Active 

h 

Est. 24-

Hour 

Charge 

Energy 

Wh 

Est. 

ActiveOnly 

System 

Eff. 

Est. 

Maint. 

Power 

W 

Est. 

NoBattery 

Power 

W 

UEC 

kWh/yr 

0 Power Tool 2 3.6 3.0 14.3 25% 0.3 - 1.5 

1 Cell Phone 2 3.6 3.0 9.4 38% 0.2 - 0.9 

2 Cell Phone 2 3.6 3.0 6.4 47% 0.1 - 0.6 

3 - - - - - - - - -

Table 5.77 Resulting cost and efficiency relationship for BC product class 8. 

MSP from MSP from 

UEC Interviews Teardowns 

CSL kWh/yr 2009$ 2009$ 

0 1.5 $0.62 -

1 0.9 $1.42 -

2 0.6 $2.17 -

3 - - -

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5.6.14.4 Scaled Product Class 9: Low Energy, 12 V DC Input 

This product class contains small consumer electronic products typically recharged using 

the 12 volt output of an automotive cigarette lighter receptacle, in particular satellite navigation 

units intended for use in cars. Through product disassembly, DOE noticed many similarities to 

the design of BCs in product class 2, though, again, without the need for an EPS, as the 12 V DC 

input is converted into the voltage necessary for battery charging and operation using a DC-DC 

converter inside the unit. Using a similar approach to that for scaled product class 8, DOE 

developed the results shown in Table 5.78 and Table 5.79 below. 

Table 5.78 Characteristics of typical units scaled for product class 9. 

CSL 

Example 

Application 

Rated 

Battery 

Energy 

Wh 

Rated 

Battery 

Voltage 

V 

Est. 

Time in 

Active 

h 

Est. 24-

Hour 

Charge 

Energy 

Wh 

Est. 

ActiveOnly 

System 

Eff. 

Est. 

Maint. 

Power 

W 

Est. 

NoBattery 

Power 

W 

UEC 

kWh/yr 

0 Power Tool 3.6 5 3.0 36.5 19% 0.5 - 1.3 

1 Cell Phone 3.6 5 3.0 23.3 27% 0.2 - 0.8 

2 Cell Phone 3.6 5 3.0 15.4 38% 0.1 - 0.5 

3 - - - - - - - - -

Table 5.79 Resulting cost and efficiency relationship for BC product class 9. 

MSP from MSP from 

UEC Interviews Teardowns 

CSL kWh/yr 2009$ 2009$ 

0 1.3 $0.62 -

1 0.8 $1.11 -

2 0.5 $2.76 -

3 - - -

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1 Environmental Protection Agency (EPA). ―ENERGY STAR Program Requirements for Products with Battery 

Charging Systems: Eligibility Criteria.‖ May 2007. 

http://www.energystar.gov/ia/partners/product_specs/program_reqs/battery_chargers_prog_req.pdf 

2 Ecos Consulting energy efficiency tests. Provided to DOE by Pacific Gas & Electric. July 7, 2009. 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

CHAPTER 6. PRODUCT PRICE DETERMINATION 

TABLE OF CONTENTS 

CHAPTER 6. PRODUCT PRICE DETERMINATION ................................................. 6-1
 

6.1 Introduction....................................................................................................... 6-1
 

6.2 Methodology..................................................................................................... 6-1
 

6.2.1 Key Assumptions.............................................................................................. 6-1
 

6.2.2 Role of End-Use Product Markups................................................................... 6-2
 

6.2.3 Distribution Channels ....................................................................................... 6-2
 

6.2.4 Data Sources ..................................................................................................... 6-4
 

6.2.5 Baseline Markups.............................................................................................. 6-5
 

6.2.6 Incremental Markups ........................................................................................ 6-5
 

6.3 Markups by End-Use Product Category ........................................................... 6-6
 

6.4 Markups by Battery Charger and External Power Supply Product Class......... 6-7
 

6.5 Sales Taxes........................................................................................................ 6-9
 

LIST OF TABLES 

TABLE 6.1 MARKUPS BY END-USE PRODUCT CATEGORY ............................... 6-7
 

TABLE 6.2 BASELINE MARKUP CALCULATION FOR EPS PRODUCT CLASS A3
 

TABLE 6.6 WEIGHTED AVERAGE SALES TAX RATES BY CENSUS DIVISION....
 

.......................................................................................................................................... 6-8
 

TABLE 6.3 EXTERNAL POWER SUPPLY MARKUPS BY PRODUCT CLASS...... 6-8
 

TABLE 6.4 BATTERY CHARGER MARKUPS BY PRODUCT CLASS ................... 6-9
 

TABLE 6.5 STATE AND LOCAL SALES TAX RATES ........................................... 6-10
 

........................................................................................................................................ 6-11
 

LIST OF FIGURES 

FIGURE 6.1 PATHS OF DISTRIBUTION FOR BATTERY CHARGERS AND 

EXTERNAL POWER SUPPLIES .................................................................................. 6-3
 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

 

 

CHAPTER 6. PRODUCT PRICE DETERMINATION
 

6.1 INTRODUCTION
 

This chapter presents DOE’s method for estimating the prices paid by end-use 

consumers for baseline and more efficient battery chargers (BCs) and external power 

supplies (EPSs), an analysis known as the Product Price Determination (PPD). The PPD 

draws upon the market assessment, contained in chapter 3 of this technical support 

document (TSD). The markups calculated in the PPD are necessary inputs to the lifecycle cost (LCC) and payback period (PBP) analyses, and the national impact analysis 

(NIA). 

The manufacturer selling price (MSP) is the price at which a BC/EPS 

manufacturer sells a completed BC or EPS, usually to an end-use product manufacturer 

(sometimes called an original equipment manufacturer or OEM)a

. In the engineering 

analysis, DOE estimated BC and EPS prices as MSPs for all product classes and 

representative units at each candidate standard level (CSL). In the PPD, DOE derived two 

kinds of markups, those that are applied to baseline costs (baseline markups) and those 

that are applied to incremental cost increases due to standards (incremental markups). 

Markups are applied to BCs and EPSs as they move through each step in the 

distribution chain. The markup applied by an OEM (the manufacturer markup) and the 

markup applied by an end-use consumer product retailer (the retail markup) can be 

multiplied together to yield a composite markup. The final product prices, as estimated 

using these markups and sales tax data, are used in the LCC and NIA to forecast the 

increase in BC/EPS costs to the consumer that would result from standards. 

6.2 METHODOLOGY 

6.2.1 Key Assumptions 

DOE made five key assumptions in conducting the PPD. They are explained in 

the following subsections. 

The dominant path to market establishes the retail price and, thus, the composite 

markup for a product. 

The markups applied to end-use products that use BCs and EPSs are proxies for 

BC and EPS markups. 

The baseline markups that manufacturers and retailers apply to end-use products 

that use BCs and EPSs are equal to those companies’ average markups across 

their entire product lines.
 

Expenses like labor and administrative costs remain fixed and need not be 

recovered in the incremental markup. Profits and other operating costs are
 

assumed to be variable and to scale with the MSP.
 

a For further discussion of the MSP and its derivation, see chapter 5 of this TSD. 

6-1
 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

Markups can be derived from inspection of companies’ public financial filings. 

6.2.2 Role of End-Use Product Markups 

The markups applied to end-use products are used as a proxy for BC and EPS 

markups. BC and EPS markups generally cannot be measured directly, as these products 

are typically components of, or accessories to, other end-use products. The specific 

markups for BCs and EPSs at each stage are therefore assumed to be of equivalent 

percentages to the markups applied to the end-use products they accompany. For 

example, if a printer is marked up 30 percent by a retailer, then the individual 

components of that printer, including the EPS, are assumed to be marked up 30 percent as 

well. 

6.2.3 Distribution Channels 

Each company involved in manufacturing, distributing, and selling end-use 

products applies a markup to cover business costs and maintain profit margins. To 

determine which markups are applied to the MSP, DOE first needed to model the 

distribution channels for BCs and EPSs. Figure 6.1 illustrates this model. The most 

common path to market, as identified by DOE, is depicted by the gray arrows, while 

alternative paths are depicted by the white arrows. Based on comments from the 

Association of Home Appliance Manufacturers, DOE combined the distribution models 

of BCs and EPSs. Despite minor variations, the two models are assumed to be similar in 

their basic structure. (Pub. Mtg. Tr., No. 14 at pp. 229-231) DOE based the PPD analysis 

and stages at which markups were applied on the most common path to market. 

6-2
 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

Component Manufacturer 

BC/EPS Manufacturer 

BC/EPS Distributor 

Consumer Product Retailer/Distributor 

End-Use Product Manufacturer (OEM) 

Taxes 

Consumer 

Note that the widths of arrows and sizes of boxes are not drawn to scale and are not meant to be an exact 

indication of a distribution path’s relative prominence. 

Figure 6.1 Paths of Distribution for Battery Chargers and External Power Supplies 

BC and EPS distribution begins with component manufacturers, who produce the 

circuitry, circuitry components, wiring, housing, and other materials needed to 

manufacture BCs and EPSs. These are often sold directly to BC/EPS manufacturers, who 

produce a finished BC or EPS, often for a specific end-use product manufacturer. DOE 

identified some cases in which BCs or EPSs are manufactured directly by the OEMb

. 

BCs and EPSs are then typically purchased by an OEM, at the manufacturer 

selling price, as an input to an end-use consumer product. The BC and/or EPS is typically 

integrated into (or packaged with) a consumer product and marked up for sale to a retailer 

or, less frequently, a wholesaler. This markup applied by the OEM will be referred to as 

the manufacturer markup. While most consumer products are manufactured in an OEMowned factory, there is a trend towards the use of electronics manufacturing services 

(EMS), which make consumer products under contract to multiple OEMs and take 

advantage of economies of scale to source materials and components at lower costs. DOE 

believes that products manufactured by EMSs are marked up similarly to those 

manufactured in-house by OEMs. 

Retailers also add a markup to the consumer products they sell. DOE has 

identified a number of instances where the manufacturing and retail operations for a 

product are owned and managed by one company. An example is Apple, Inc., which 

manufactures consumer electronics that are sold in Apple-branded retail stores. DOE 

b For OEM’s, it is more common to manufacture BCs in-house than it is to manufacture EPSs in-house. 

6-3
 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

believes that the markups on these products are similar to the combination of the 

manufacturer and retailer markups found on other products, allowing the company to 

maintain gross margins competitive with other companies in the industry. 

It is the OEM and retailer markups that DOE applied to the MSP in this analysis 

to determine the end-user product prices of BCs and EPSs. The MSP already takes into 

account BC/EPS manufacturer markups. The majority of states and some local 

governments then impose a sales tax, resulting in the final cost to consumers. Sales taxes 

are discussed further in section 6.5. 

A note on distributors 

Some OEMs, particularly smaller manufacturers, opt to source components 

through distributors for a variety of reasons, such as easier access to a wider array of 

components. Distributors tend to have low margins and, due to high sales volumes, can 

purchase and sell products at reduced prices. Distributors represent an additional step in 

the chain; however, this step is uncommon. Given DOE’s assumption that the most 

common path to market sets the final product price, the presence of an EPS or BC 

distributor in the distribution chain is assumed not to affect the final product price. 

The distribution of EPSs and BCs for medical devices differs from those for other 

devices, as many medical devices are prescribed by a doctor and are not available at 

traditional retail outlets. These devices are therefore sold by medical distributors, rather 

than retailers. DOE calculated the retail markups for medical devices using the financial 

information from several large medical device distributors. 

High-power EPSs used in amateur radio setups are typically sold as individual 

components through small, specialized retailers. DOE assumes that these retailers 

commonly purchase EPSs from EPS distributors rather than EPS manufacturers, given 

their small purchasing volume. As such, the two markups that DOE applies to amateur 

radios are a distributor markup (in lieu of an OEM markup) and a retailer markup. 

6.2.4 Data Sources 

Individual product markups are generally confidential and are not readily 

available. As such, DOE used corporate sales revenue and the direct costs of products 

sold, known as costs of goods sold (COGS), to estimate the average baseline markup 

applied to all products that a company manufactures or sells. For each company analyzed, 

DOE calculated and averaged markups for all fiscal years reported in the company’s most 

recent annual report (as far back as fiscal year 2006) to arrive at the average markup. The 

average markup was then used to estimate the markups applied to the company’s relevant 

products that use BCs and/or EPSs. DOE sourced financial data from publicly available 

filings with the Securities and Exchange Commission (SEC) for all domestic companies 

analyzed, as well as for those foreign companies trading under an American Depositary 

Receipt (ADR). For foreign public companies that trade only on foreign stock exchanges, 

markups were calculated from annual reports and financial statements published on those 

companies’ websites. DOE relied on these data under the assumption that financial data 

6-4
 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

MU BASE

 

 

 

COGS

 

 

 

 

reported by a publicly traded company in a quarterly or annual report have been verified 

by an independent, certified auditor, and can therefore be considered accurate. 

6.2.5 Baseline Markups 

A markup is a percentage increase added to the input costs of a good or service so 

that a company can cover its costs and earn a profit. Gross margin is the component of a 

product’s price, added to COGS, that includes overhead costs (selling, general, and 

administrative), research and development, other expenses, and profits. To calculate 

baseline markups, DOE used the following equation: 

EQ 1 

COGS

REV

GM

MUBASE 1

1

where: 

REV

REV COGS GM

EQ 2 

and: 

= baseline manufacturer or retailer markup,
 

= corporate gross margin as a percentage of revenue,
 

= revenue of the OEM/retailer, and
 

= cost of goods/services manufactured or sold.
 

GMREV

For example, if a computer manufacturer operates with revenues of $100 million 

and has a COGS of $80 million, then the above calculations yield 1.25, or a markup of 25 

percent applied to all computers manufactured. Therefore, it is assumed that any BCs or 

EPSs integrated into the company’s computer during the manufacturing process will be 

marked up 25 percent. 

6.2.6 Incremental Markups 

DOE assumes a division of costs between those that do not scale with the MSP 

(fixed costs) and those that do (variable costs). DOE used the baseline markups 

(MUBASE), which cover all of a retailer’s costs (i.e., both fixed and variable costs), to 

determine the sales price of baseline models. The composite baseline markup relates the 

BC/EPS MSP to the final product price. DOE considers baseline models to be equipment 

sold under existing market conditions (i.e., without new energy efficiency standards). 

DOE calculated the baseline markups for manufacturers and retailers using Equation 1. 

Incremental markups (MUINCR) are coefficients that relate the change in the 

BC/EPS MSP of higher-efficiency models (incremental cost) to the change in the final 

product price. Incremental markups are applied only to the incremental cost of these 

higher efficiency models; the baseline markup is still applied to the baseline portion of 

6-5
 

EERE-2008-BT-STD-0005 COMMENT 31
MUINCR

 

 

COGS

 

MURET,i

MU MFG,i

 

MUCOMP,i

 

 

 

 

MUCOMP,i MU MFG,i MURET ,i

the MSP. Incremental markups cover only those costs that scale with a change in the 

MSP (i.e., variable costs). The surveyed public financial filings did not typically separate 

labor and occupancy costs from overall expenses, so DOE assumed these fixed costs to 

be encompassed by “selling, general, and administrative expenses” (SG&A), which are 

typically reported in financial statements. Incremental markups were calculated using the 

following equation: 

EQ 3 

COGS

REV SGA

COGS

REV COGS SGA MUINCR 1

where: 

= incremental manufacturer or retailer markup, 

= revenue of the OEM/retailer, and 

= cost of goods/services manufactured or sold 

= selling, general, and administrative expenses 

REV SGA

6.3 MARKUPS BY END-USE PRODUCT CATEGORY 

To determine the markup applied to each BC and EPS product class (or 

representative unit), DOE first assigned each application to one of 16 end-use product 

categories, grouped by industry and similarity in manufacturing and/or retail practices. A 

categorized list of end-use product applications is available in the Excel workbook that 

accompanies this chapter. DOE then gathered gross margin data and calculated baseline 

and incremental markups for the leading, publicly traded end-use product manufacturers 

and retailersc in each category. DOE then calculated simple-average retailer and 

manufacturer markups for each category and multiplied those two markups together to 

obtain a composite markup for the category using equation 4: 

EQ 4 

where: 

= simple average retailer markup in category i, 

= simple average manufacturer markup in category i, and 

= composite markup applied to BCs and EPSs that power applications in 

category i 

Table 6.1 shows the retailer, manufacturer, and composite baseline and incremental 

markups DOE calculated for each end-use product category. 

c Determined by product surveys, research reports, and most popular products on top retail websites such as 

www.amazon.com. 

6-6
 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

 

 

Table 6.1 Markups by End-Use Product Category 

End-Use Product 

Category 

Manufacturer Markup Retailer Markup Composite Markup 

Baseline Incremental Baseline Incremental Baseline Incremental 

Portable Audio & 

Accessories 1.42 1.15 1.48 1.16 2.11 1.34 

Mobile Telephony 1.52 1.29 1.41 1.13 2.14 1.46 

Stationary 

Telephony 1.47 1.17 1.40 1.13 2.06 1.32 

Computers / 

Accessories 1.35 1.15 1.39 1.14 1.89 1.31 

Printers / MFDs 1.47 1.15 1.35 1.13 1.99 1.31 

Geospatial 

Equipment 1.86 1.51 1.40 1.12 2.60 1.69 

Power Tools / 

Outdoor 

Appliancesd 

1.51 1.16 1.42 1.16 2.14 1.34 

Transport 1.55 1.20 1.49 1.14 2.31 1.37 

Photo / Video 1.53 1.12 1.40 1.12 2.14 1.26 

Floor Care 1.41 1.14 1.42 1.15 2.00 1.30 

Games / 

Entertainment 1.61 1.29 1.41 1.12 2.27 1.45 

Personal Care 1.45 1.10 1.38 1.11 2.00 1.23 

Medical 1.93 1.40 1.31 1.06 2.53 1.48 

Home Systems 1.37 1.11 1.48 1.18 2.04 1.31 

Amateur Radios 1.15* 1.03 1.47 1.13 1.69 1.16 

Uninterruptible 

Power Supply 1.35 1.15 1.49 1.17 2.01 1.35 

Other** 1.48 1.18 1.47 1.13 2.17 1.33 

* The first markup applied to amateur radios is an EPS distributor markup, rather than an OEM markup. 

**“Other” contains applications that do not fit cleanly into any of the other 15 categories. Its markup was 

calculated by multiplying the simple averages of all individual manufacturer and retailer markups. 

6.4	 MARKUPS BY BATTERY CHARGER AND EXTERNAL POWER SUPPLY 

PRODUCT CLASS 

In the engineering analysis, DOE identified 10 BC product classes and 15 EPS 

product classes. Since, by design, each BC/EPS application can be found in only one of 

the end-use product categories listed in Table 6.1, each BC/EPS end-use application is 

associated with one composite markup. To calculate the markup for a product class (or, in 

the case of EPS product class A1, one of four segments within that class), DOE 

calculated the shipment-weighted average of the markups for applications associated with 

that class. Table 6.2 gives an example of this. 

d Interviews with at least one manufacturer indicated that DOE’s retail markup estimate is high and that a 

markup of 1.13 may be more accurate. SEC data suggests that the retailer markup for power tools is 1.41. If 

DOE identifies or receives further evidence supporting a lower markup for power tools or an alternate 

manufacturer or retailer markup for any category, it will consider revising its estimates accordingly. 

6-7
 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

Table 6.2 Baseline Markup Calculation for EPS Product Class A3 

EPS Product Class A3: AC-AC, Basic Voltage 

Application Shipments in 

Class A3 

Shipments as 

Percent of 

Product Class 

Baseline 

Markup 

Home Security Systems 

Aquarium Accessories 

Water Softeners/Purifiers 

Indoor Fountains 

Irrigation Timers 

4,219,000 

1,750,000 

1,150,000 

500,000 

375,000 

52.8% 

21.9% 

14.4% 

6.3% 

4.7% 

2.04 

2.17 

2.04 

2.17 

2.04 

Product Class Markup (weighted average markup) 2.07 

Table 6.3 and Table 6.4 display the results of these calculations for each BC and 

EPS product class. A list of applications associated with each class can be found in the 

market assessment (chapter 3) and the Excel workbook that accompanies the market 

assessment. 

Table 6.3 External Power Supply Markups by Product Class 

Output Class ID 

Composite 

Baseline 

Markup 

Composite 

Incremental 

Markup 

Class A 

AC-DC 

Basic 

Voltage 

A1: 0-10.25 W 

A1: 10.25-39 W 

A1: 39-90 W 

A1: 90-250 W 

2.16 

2.00 

2.00 

1.89 

1.40 

1.31 

1.34 

1.31 

Low Voltage A2 2.19 1.47 

AC-AC Basic 

Voltage A3 2.07 1.31 

Low Voltage A4 2.17 1.33 

Non-Class A 

Multiple-Voltage 100 W 

≥100 W 

X1 

X2 

1.99 

2.27 

1.31 

1.45 

High Power >250 W H1 1.69 1.16 

For Medical 

Devices 

AC-DC Basic 

Voltage 

Low Voltage 

M1 

M2 

2.53 

2.53 

1.48 

1.48 

AC-AC Basic 

Voltage M3 N/A* N/A* 

Low Voltage M4 N/A* N/A* 

6-8
 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

Output Class ID 

Composite 

Baseline 

Markup 

Composite 

Incremental 

Markup 

For MotorOperated BC 

Applications 

and Detachable 

Batteries 

AC-DC Basic 

Voltage 

Low Voltage 

B1 

B2 

2.16 

2.01 

1.35 

1.23 

AC-AC Basic 

Voltage 

Low Voltage 

B3 

B4 

N/A* 

N/A* 

N/A* 

N/A* 

* DOE did not identify any products in this class. 

Table 6.4 Battery Charger Markups by Product Class 

Battery 

Energy 

Battery 

Voltage Class ID 

Composite 

Baseline 

Markup 

Composite 

Incremental 

Markup 

ACDC 

<100 Wh 

Inductive 

Connection 

<4 V 

4–10 V 

>10 V 

1 

2 

3 

4 

2.00 

2.13 

2.17 

1.98 

1.23 

1.40 

1.33 

1.32 

100–3000 

Wh 

<20 V 

≥20 V 

5 

6 

2.32 

2.28 

1.37 

1.36 

>3000 Wh 7 2.31 1.37 

DC-DC <9 V Input 

≥9 V Input 

8 

9 

2.12 

2.60 

1.38 

1.69 

AC-AC AC Output 

from Battery 10 2.01 1.35 

6.5 SALES TAXES 

A sales tax is a multiplicative factor applied to a product’s retail price that 

increases the user’s first cost. DOE obtained information on State and local sales taxes 

from the Sales Tax Clearinghouse. These data are displayed in Table 6.5 as weighted 

averages that include county and city sales tax rates. 

6-9
 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

Table 6.5 State and Local Sales Tax Rates 

State 

Combined 

State and 

Local Tax 

Rate 

(%) 

State 

Combined 

State and 

Local Tax 

Rate 

(%) 

State 

Combined 

State and 

Local Tax 

Rate 

(%) 

Alabama 8.15 Kentucky 6.00 North 

Dakota 

5.80 

Alaska 1.50 Louisiana 8.75 Ohio 6.85 

Arizona 7.15 Maine 5.00 Oklahoma 8.15 

Arkansas 8.25 Maryland 6.00 Oregon 0.00 

California 9.15 Massachusetts 6.25 Pennsylvania 6.40 

Colorado 6.40 Michigan 6.00 Rhode Island 7.00 

Connecticut 6.00 Minnesota 7.20 South 

Carolina 

7.05 

Delaware 0.00 Mississippi 7.00 South 

Dakota 

5.50 

Dist. Of 

Columbia 

6.00 Missouri 7.05 Tennessee 9.40 

Florida 6.70 Montana 0.00 Texas 8.05 

Georgia 6.95 Nebraska 6.00 Utah 6.70 

Hawaii 4.40 Nevada 7.85 Vermont 6.05 

Idaho 6.05 New 

Hampshire 

0.00 Virginia 5.00 

Illinois 8.40 New Jersey 6.95 Washington 8.75 

Indiana 7.00 New Mexico 6.40 West 

Virginia` 

6.00 

Iowa 6.85 New York 8.45 Wisconsin 5.40 

Kansas 7.00 North 

Carolina 

7.80 Wyoming 5.25 

Source: Sales Tax Clearinghouse1 

DOE then calculated average tax rates for each Census division and four large 

States, weighted by 2008 state-level population. The population-weighted sales tax by 

division is displayed in Table 6.6. Developing this distribution allowed DOE to correlate 

the sales tax distribution with the electricity price distribution in the LCC. The table also 

displays the national, population-weighted average sales tax that is used in the NIA, 

where DOE did not use a distribution of inputs. 

6-10
 

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Table 6.6 Weighted Average Sales Tax Rates by Census Division 

Division & Large 

State Name 2008 Population 

PopulationWeighted Sales Tax 

(%) 

New England 14,429,720 5.55 

Mid Atlantic 21,312,506 6.62 

East North Central 46,500,668 6.94 

West North Central 20,336,243 6.86 

South Atlantic 40,657,961 6.44 

East South Central 18,271,071 7.89 

West South Central 11,068,576 8.42 

Mountain 22,122,914 6.50 

Pacific 12,483,503 5.21 

New York State 19,541,453 8.45 

California 36,961,664 9.15 

Texas 24,782,302 8.05 

Florida 18,537,969 6.70 

U.S. Weighted Average: 7.23% 

Source: DOE analysis of data from the Sales Tax Clearinghouse and U.S. Census Bureau2 

6-11
 

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REFERENCES 

1 Sales Tax Clearinghouse, Inc. State sales tax rates along with combined average city and county rates. 

2009. (Last accessed October 6, 2009). <https://thestc.com/STRates.stm> 

2 U.S. Census Bureau. Annual Estimates of the Resident Population for the United States, Regions, States, 

and Puerto Rico: April 1, 2000 to July 1, 2008, 2008. (Last Accessed October 6, 2009). Washington, DC. 

<http://www.census.gov/popest/states/tables/NST-EST2008-01.xls > 

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CHAPTER 7. ENERGY USE ANALYSIS
 

TABLE OF CONTENTS
 

CHAPTER 7. ENERGY USE ANALYSIS................................................................................. 7-1
 

7.1 External Power Supplies...................................................................................... 7-2
 

7.1.1 Modes and Application States ................................................................. 7-2
 

7.1.2 Loading Points ......................................................................................... 7-5
 

7.1.3 Calculating External Power Supply Energy Use ..................................... 7-6
 

7.1.4 EPS Power by Mode of Operation........................................................... 7-7
 

7.1.5 External Power Supply Usage Profiles .................................................. 7-10
 

7.1.6 External Power Supply Unit Energy Consumption Values ................... 7-11
 

7.2 Battery Chargers ................................................................................................ 7-15
 

7.2.1 Battery Charger Modes.......................................................................... 7-15
 

7.2.2 Battery Charger Usage Profiles ............................................................. 7-16
 

7.2.3 Calculating Battery Charger Energy Use............................................... 7-18
 

7.2.4 Battery Charger Unit Energy Consumption Values............................... 7-21
 

LIST OF TABLES 

TABLE 7.1 SUMMARY OF EPS MODES................................................................................ 7-2
 

TABLE 7.2 NOTEBOOK COMPUTER APPLICATION STATES AND LOADING POINTS ...
 

TABLE 7.4 PORTABLE DVD PLAYER APPLICATION STATES AND LOADING POINTS
 

TABLE 7.6 DEFAULT APPLICATION STATES AND LOADING POINTS FOR EPS USED 

TABLE 7.9 EXTERNAL POWER SUPPLY REPRESENTATIVE UNIT AND ASSOCIATED 

TABLE 7.10 EXTERNAL POWER SUPPLY UNIT ENERGY CONSUMPTION (KWH/YR) ...
 

TABLE 7.17 MODE-SPECIFIC PERFORMANCE CHARACTERISTICS –
 

TABLE 7.18 MODE-SPECIFIC PERFORMANCE CHARACTERISTICS – TEST AND 

.......................................................................................................................................... 7-4
 

TABLE 7.3 LAN EQUIPMENT APPLICATION STATES AND LOADING POINTS........... 7-4
 

.......................................................................................................................................... 7-4
 

TABLE 7.5 DEFAULT EPS APPLICATION STATES AND LOADING POINTS................. 7-5
 

WITH BC......................................................................................................................... 7-5
 

TABLE 7.7 GENERIC EPS USAGE PROFILES..................................................................... 7-10
 

TABLE 7.8 GENERIC EPS USAGE PROFILE FOR A BC APPLICATION......................... 7-11
 

POWER OUTPUT RANGE.......................................................................................... 7-12
 

........................................................................................................................................ 7-13
 

TABLE 7.11 PRODUCT CLASS A1 – 2.5 WATT REPRESENTATIVE UNIT .................... 7-13
 

TABLE 7.12 PRODUCT CLASS A1 – 18 WATT REPRESENTATIVE UNIT ..................... 7-14
 

TABLE 7.13 PRODUCT CLASS A1 – 60 WATT REPRESENTATIVE UNIT ..................... 7-15
 

TABLE 7.14 PRODUCT CLASS A1 – 120 WATT REPRESENTATIVE UNIT ................... 7-15
 

TABLE 7.15 GENERIC BATTERY CHARGER USAGE PROFILES................................... 7-17
 

TABLE 7.16 BC SHIPMENTS-WEIGHTED AVERAGE USAGE PROFILES..................... 7-18
 

MANUFACTURER DATA .......................................................................................... 7-23
 

TEARDOWN DATA..................................................................................................... 7-24
 

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TABLE 7.19 BATTERY CHARGER UNIT ENERGY CONSUMPTION BY PRODUCT 

CLASS BASED ON MANUFACTURER-SUPPLIED DATA (KWH/YR) ................ 7-25
 

TABLE 7.20 BATTERY CHARGER UNIT ENERGY CONSUMPTION BY PRODUCT 

TABLE 7.21 BATTERY CHARGER PRODUCT CLASS 1 – BASED ON MANUFACTURERTABLE 7.22 BATTERY CHARGER PRODUCT CLASS 2 – BASED ON MANUFACTURERTABLE 7.23 BATTERY CHARGER PRODUCT CLASS 2 – BASED ON TEST &
 

TABLE 7.24 BATTERY CHARGER PRODUCT CLASS 3 – BASED ON MANUFACTURERTABLE 7.25 BATTERY CHARGER PRODUCT CLASS 4 – BASED ON MANUFACTURERTABLE 7.26 BATTERY CHARGER PRODUCT CLASS 4 – BASED ON TEST &
 

TABLE 7.27 BATTERY CHARGER PRODUCT CLASS 5 – BASED ON MANUFACTURERTABLE 7.28 BATTERY CHARGER PRODUCT CLASS 5 – BASED ON TEST &
 

TABLE 7.29 BATTERY CHARGER PRODUCT CLASS 6 –BASED ON MANUFACTURERTABLE 7.30 BATTERY CHARGER PRODUCT CLASS 7 – BASED ON MANUFACTURERTABLE 7.31 BATTERY CHARGER PRODUCT CLASS 8 – BASED ON MANUFACTURERTABLE 7.32 BATTERY CHARGER PRODUCT CLASS 9 – BASED ON MANUFACTURERTABLE 7.33 BATTERY CHARGER PRODUCT CLASS 10 – BASED ON 

TABLE 7.34 BATTERY CHARGER PRODUCT CLASS 10 – BASED ON TEST &
 

CLASS BASED ON TEST AND TEARDOWN DATA (KWH/YR) .......................... 7-25
 

SUPPLIED DATA......................................................................................................... 7-26
 

SUPPLIED DATA......................................................................................................... 7-27
 

TEARDOWN DATA..................................................................................................... 7-27
 

SUPPLIED DATA......................................................................................................... 7-27
 

SUPPLIED DATA......................................................................................................... 7-28
 

TEARDOWN DATA..................................................................................................... 7-28
 

SUPPLIED DATA......................................................................................................... 7-29
 

TEARDOWN DATA..................................................................................................... 7-29
 

SUPPLIED DATA......................................................................................................... 7-30
 

SUPPLIED DATA......................................................................................................... 7-30
 

SUPPLIED DATA......................................................................................................... 7-30
 

SUPPLIED DATA......................................................................................................... 7-31
 

MANUFACTURER-SUPPLIED DATA ...................................................................... 7-31
 

TEARDOWN DATA..................................................................................................... 7-31
 

LIST OF FIGURES 

FIGURE 7.1 CHARGING INPUT POWER OVER TIME (PORTABLE VIDEO GAME 

CONSOLE)...................................................................................................................... 7-6
 

FIGURE 7.2 EXAMPLE MEASUREMENTS FROM AN EPS TEST PROCEDURE ............. 7-8
 

FIGURE 7.3 RELATIONSHIP BETWEEN EPS INPUT POWER AND OUTPUT POWER AT 

FIVE LOADING POINTS .............................................................................................. 7-9
 

FIGURE 7.4 CALCULATING CHARGE ENERGY CONSUMPTION FROM 24-HOUR 

ENERGY ....................................................................................................................... 7-19
 

FIGURE 7.5 ACTIVE AND MAINTENANCE TIME............................................................. 7-20
 

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CHAPTER 7. ENERGY USE ANALYSIS 

The purpose of the energy use analysis is to identify how consumers use products and 

equipment, and thereby determine the energy savings potential of energy-efficiency 

improvements. For battery chargers (BCs) and external power supplies (EPSs), DOE’s analysis

focuses on how end users operate BCs and EPSs with the consumer products they power. 

It is in the energy use analysis that DOE derives unit energy consumption (UEC), which 

is an input to the life-cycle cost (LCC) and payback period (PBP) analyses described in chapter 

8. The LCC and PBP analyses require data on annual energy use because these data, along with 

energy prices, establish the operating costs. 

The engineering analysis described in chapter 5 reports energy use based on the DOE test 

procedures. These tests provide standardized results that serve as the basis for comparing the 

performance of different BCs and EPSs used under the same conditions. Actual usage in the field 

varies depending on the conditions in which the appliances are operated.a The unit energy 

consumption calculated in this chapter represents the typical annual energy consumption of a BC 

or EPS in the field. A critical part of characterizing end-use loads for BCs and EPSs is 

identifying usage profiles, which estimate the time a device spends in each mode in one year. 

Because of the nature of BCs and EPSs, the usage profile of the device will be related to the 

usage profile of the associated application. It is difficult to predict changes in usage, so DOE 

assumes that usage profiles will not change over the analysis period. 

BCs and EPSs are power conversion devices that transform input voltage to suitable 

voltage for the end-use application or battery they are powering. To provide that output power, 

EPSs and BCs consume power due to internal losses as well as overhead circuitry. The amount 

of power the EPSs and BCs consume varies with the power demands of the load. Therefore, the 

traditional method for calculating energy consumption by measuring the energy a product draws 

from mains while performing its intended function(s) is not appropriate for BCs and EPSs. 

Instead, energy consumption is taken to be the energy dissipated by the BC or EPS (losses) and 

not delivered to the end-use product or battery. Once the energy and power requirements of those 

end-use products and batteries have been determined, they are considered fixed, and DOE 

considers only how standards would affect the energy consumption of BCs and EPSs themselves. 

DOE used a single usage profile for each application to calculate unit energy 

consumption for BCs and EPSs. However, usage varies by application and among users. For 

some applications DOE developed an average usage profile based on different user types. The 

following are some applications with usage profiles derived from more than one user type: 

Digital cameras 

Golf cars 

Ink Jet Imaging Equipment 

Notebook Computers 

a DOE estimated the power requirements and usage of various end-use applications that use BCs and EPSs based on 

published reports, comments from interested parties, and test data. Unfortunately, some of the estimates were not 

based on metered data but rather relied on power measurements and assumptions regarding usage. When data were 

unavailable, DOE relied on its own estimates of power and usage. 

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Professional-grade power tools 

Two-way radios 

Video Game Consoles 

DOE examined multiple usage profiles for applications where usage varies widely. 

Typically, DOE examined a light user and a heavy user. Although user types vary significantly, a 

heavy user might, for example, be found in the commercial sector, whereas light users might 

often be found in the residential sector. 

Section 7.1 explains how DOE calculated EPS energy consumption while section 7.2 is 

devoted to BC energy consumption. There are two appendices associated with this chapter. 

Appendix 7A shows application-level usage profiles, while Appendix 7B shows applicationlevel UECS. 

7.1 EXTERNAL POWER SUPPLIES 

This section describes EPS modes and application states, how UEC is calculated, and 

results for each product class. 

7.1.1 Modes and Application States 

When describing usage and energy consumption from the perspective of the EPS, DOE 

uses the term ―EPS mode.‖ When describing usage and energy consumption from the perspective 

of the application, DOE uses the term ―application state.‖

7.1.1.1 EPS Modes 

An EPS can be in active mode, no-load mode, off mode, or unplugged. Table 7.1 gives a 

summary of these modes, which are also discussed in chapter 3. 

Table 7.1 Summary of EPS Modes 

EPS Mode Status of EPS 

Connection to 

Mains 

Status of EPS 

Connection to 

Application 

EPS On/Off Switch 

Selection 

(If Switch is Present) 

Active Connected Connected On 

No-load Connected Disconnected On 

Off Connected Disconnected Off 

Unplugged Disconnected — —

Active Mode: In active mode, the external power supply takes power from mains and 

converts it to a form usable by the consumer product or load. Thus, in calculating usage profiles 

and energy consumption, DOE considers active mode to include any condition where the EPS is 

connected to both mains and the application. 

No-Load Mode: EPCA defines no-load mode for EPSs as the mode of operation when an 

external power supply is connected to the main electricity supply and the output is not connected 

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EERE-2008-BT-STD-0005 COMMENT 31
to a load. (42 U.S.C. 6291(36)(D)) DOE determined that for EPSs, no-load mode is equivalent to 

standby, as explained in the ―Final Rule on Test Procedures for Battery Chargers and External 

Power Supplies (Standby Mode and Off Mode),‖ published in the Federal Register on March 27, 

2009. (74 FR 13318) 

Off Mode: Off mode is a mode applicable only to an EPS with an on/off switch in which 

the EPS is connected to mains, is disconnected from the load, and the on/off switch is set to 

―off.‖ This definition was promulgated in the final rule reference just above. Of the EPSs DOE 

examined, only two Non-Class A high power units, which are used with amateur radios, included 

on/off switches. In both cases, turning off the switch fully severed the circuit, creating a situation 

electrically equivalent to the EPS being unplugged from mains. To estimate energy consumption, 

DOE treated the time when the EPS switch is set to off as equivalent to unplugged time. 

Unplugged: Unplugged simply means the EPS is disconnected from mains power. No 

energy is consumed in this state. 

7.1.1.2 Application States 

All energy-consuming application states are part of active mode from the perspective of 

the EPS. That is, since any energy-consuming application state requires the application to be 

connected to the EPS, any energy-consuming application state is part of EPS active mode. The 

number of states and power each requests varies by application. 

DOE identified application states and loading points for each application. Loading points 

are expressed relative to nameplate output power, which is the most power an EPS is capable of 

delivering. DOE conducted loading point tests for three applications. Application states and the 

corresponding loading points for these three applications are shown in Table 7.2, Table 7.3, and 

Table 7.4. The average (across the three tested units) of the loading point corresponding to the 

highest application state was 60 percent of nameplate output power. DOE used this loading point 

as the default loading point in the operating application state. DOE assumed a 2 percent load 

when the application is idle, and a load of 1 percent of nameplate output power when it is off or 

―asleep‖. The default loading points DOE used when test data were not available are shown in 

Table 7.5 and Table 7.6. 

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Table 7.2 Notebook Computer Application States and Loading Points 

EPS Mode Application State Description Percent of 

Nameplate 

Output Power 

Active 

Charging the 

Battery and 

Operating 

Device is charging the battery while 

operating (no USB devices are attached). 

(Sum of ―Operating‖ and ―Charging the 

Battery‖)

66% 

Operating - High Device is on, battery is fully charged, 

DVD drive is operating, USB devices 

attached and powered. 

60% 

Charging the 

Battery 

Device is charging the battery while in 

device is turned off. 

38% 

Operating Device is on, battery is fully charged, 

DVD drive is not operating, no USB 

devices attached. 

28% 

Sleep Device is sleeping, battery is fully 

charged, DVD drive is not operating, no 

USB devices attached. 

1.6% 

Off Device is off, battery is fully charged, 

DVD drive is not operating, no USB 

devices attached. 

0.6% 

Source: Test results. 

Table 7.3 LAN Equipment Application States and Loading Points 

EPS Mode Application State Description Percent of 

Nameplate 

Output Power 

Active 

Operating -

Transmitting 

Device is on and transmitting data. 57% 

Operating – Not 

Transmitting 

Device is on but not transmitting data. 54% 

Source: Test results. 

Table 7.4 Portable DVD Player Application States and Loading Points 

EPS Mode Application State Description Percent of 

Nameplate 

Output Power 

Active 

Operating - High Device is on and operating, battery is fully 

charged. 

60% 

Idle Device is on and idle, battery is fully 

charged. 

54% 

Off Device is off, battery is fully charged. 1% 

Source: Test results. 

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Table 7.5 Default EPS Application States and Loading Points 

EPS Mode Application State Description Percent of 

Nameplate 

Output Power 

Active 

Operating - High Application is performing its intended 

function. 

60% 

Idle/Sleep Application is in idle, ready, or sleep 

mode. 

2% 

Off Application is turned off 1% 

Source: DOE estimates. 

Table 7.6 Default Application States and Loading Points for EPS used with BC 

EPS Mode Application State Description Percent of 

Nameplate 

Output Power 

Active 

Charging the 

Battery 

BC is charging the application’s battery. 37% 

Maintenance BC is in maintenance mode 17% 

Source: DOE estimates. 

7.1.2 Loading Points 

For BC applications powered by an EPS, DOE examined test data to determine 

appropriate loading points to characterize charging and maintenance application states. The 

power requested by a BC varies considerably during charging, as illustrated by Figure 7.1. DOE 

estimated average input power over the duration of a single charge by dividing estimated BC 

active energy by estimated charge time. From this value, DOE deduced average EPS output 

power during a charge using the tested average active-mode efficiency of the EPS. Given the 

nameplate output power and average output power over a charge, DOE calculated the average 

loading point over a charge. DOE test results indicated an average maintenance mode loading 

point of 17 percent of nameplate output power. Application states and loading points for each 

EPS application examined are in appendix 7A. 

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0 

1 

2 

3 

4 

5 

Input Power 

Elapsed Time 

Figure 7.1 Charging Input Power over Time (Portable Video Game Console) 

7.1.3 Calculating External Power Supply Energy Use 

EPS energy consumption (UEC) is the sum of energy consumed in active mode 

(UECActive) and in no-load mode (UECNL). 

UEC = UECActive + UECNL 

To describe EPS active-mode energy, UECActive, it is necessary to examine each activemode state: 

UECActive = UECActive1 + UECActive2 + UECActive3 + ... 

Where UECActive(i) is EPS active-mode energy in application state i. EPS active-mode 

energy in each application state is the product of EPS active power, PActive(i), and time, tActive(i) in 

each state. Therefore, 

UECActive(i) = PActive(i) × tActive(i) 

and 

UECActive = PActive1 × tActive1 + PActive2 × tActive2 +PActive3 × tActive3 +...

No-Load mode energy is given as: 

UECNL = PNo-Load × tNo-Load 

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Where PNo-Load is no-load power and tNo-Load is time in no-load. Combining active and noload mode values provides total EPS unit energy consumption: 

UEC =PActive1 × tActive1 + PActive2 × tActive2 +PActive3 × tActive3 +...+ PNo-Load × tNoLoad 

Thus, to calculate the energy consumption of an EPS, DOE combined the time values 

(from usage profiles) with power values. Section 7.1.4 explains how these power values were 

calculated, and section 7.1.5 explains how the time values were derived. 

7.1.4 EPS Power by Mode of Operation 

No-load mode power (PNo-Load) is the measured power drawn by the EPS from mains 

while in no-load mode. Because the EPS is disconnected from the application, all of the power 

drawn from mains is consumed by the EPS. For each candidate standard level (CSL), an 

associated no-load mode power is given. 

EPS power in active mode is a function of four factors: the nameplate output power of the 

EPS, the proportion of full load required by the application (as discussed above), the active-mode 

efficiency of the EPS, and no-load mode power. EPS power during active mode varies as the 

power requirements of its load vary. 

DOE used two different approaches to calculate EPS power in active mode—one for 

application states requiring 25 percent or more of the EPS’s nameplate output power and another

for application states requiring less than 25 percent. 

The approach for application states requiring 25 percent or more of the EPS’s nameplate 

output power is straightforward. The EPS test procedure measures the active-mode efficiency 

(ηEPS) of the EPS at 25, 50, 75, and 100 percent of nameplate output power or current. The 

active-mode efficiency of the EPS is then defined as the average of these four values (points 2, 3, 

4, and 5 in Figure 7.2). As such, power is 

PActive = POut × (1/ ηEPS – 1) 

For example, an EPS delivering an output power of 10 watts at 75 percent efficiency 

would consume: 

PActive = 10 W × (1/0.75 – 1) = 3.33 W 

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Input Power

Output Power (Percent of Nameplate)

X

X

(0W, PNL)

1

2

X

X

X

0% 25% 50% 75% 100%

3

4

5

Figure 7.2 Example Measurements from an EPS Test Procedure 

The approach for application states requiring less than 25 percent of the EPS’s nameplate 

output power blends measures of the EPS’s active-mode efficiency and no-load mode power. 

Most applications have some application states that require an output power below 25 percent of 

nameplate. Additionally, many applications spend a significant portion of time in these states. 

However, at these low power levels, the efficiency of an EPS is relatively low. Thus, DOE does 

not use the active-mode efficiency measurement alone. 

Instead, DOE calculates energy consumption in this region by interpolating between two 

known points: (1) the no-load mode power and (2) the active-mode power at 25 percent of 

nameplate output power. These are points 1 and 2 in Figure 7.3. At an output power of 25 

percent, the energy consumed by the EPS is: PActive = POut × (1/ηEPS – 1). At an output power of 

0 percent (no-load mode), EPS power is: P = PNL. Given these two known values, DOE assumes 

that the energy consumed by an EPS at an output power between 0 and 25 percent of nameplate 

output power must fall on a curve between these two points. 

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Input Power

Output Power (Percent of Nameplate)

X

X

(0W, PNL)

(25% x PNameplate, 25% x [PNameplate / η])

1

2

X

X

X

0% 25% 50% 75% 100%

3

4

5

Figure 7.3 Relationship between EPS Input Power and Output Power at Five Loading 

Points 

DOE approximates this curve with a straight line between points 1 and 2, which can be 

described by the following equation relating input power to output power: 

PIn = m x POut + B 

Where B is the y-axis intercept, or PNL, and m is the slope, or: 

m = ∆y/∆x
 

m = [(25% × [PNameplate / ηEPS]) – PNL] / [(25% × PNameplate) – 0]
 

Thus, for output power levels below 25 percent of nameplate output power, the input 

power of the EPS is: 

PIn = {[(25% × [PNameplate / ηEPS]) – PNL] / [25% × PNameplate]} × POut + PNL 

Since
 

PActive = PIn – POut
 

Then 

PActive = {[(25% × [PNameplate / ηEPS]) – PNL] / [25% × PNameplate]} × POut + PNL – POut 

Or 

PActive = ({[(25% × [PNameplate / ηEPS]) – PNL] / [25% × PNameplate]}-1) × POut + PNL 

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7.1.5 External Power Supply Usage Profiles 

Because usage of an EPS is tied to usage of the application, DOE identified usage 

profiles for a variety of applications. Usage profiles for many of the most common applications 

were developed based on published research and stakeholder comments. Notable exceptions 

include computer speakers and portable video game systems. Where usage data were lacking, 

DOE assigned the application a generic usage profile. The five generic EPS usage profiles DOE 

used in the preliminary analysis are shown in Table 7.7. For EPSs that power BC applications, 

DOE assigned a usage profile that is consistent with the associated BC profile. An example of 

this is shown in Table 7.8. All usage profiles and sources are shown in appendix 7B. 

DOE used a single usage profile for each application to calculate unit energy 

consumption. For most applications the usage profile represents a typical user. However, usage 

can vary significantly depending on the user. Therefore, for some applications, including 

notebook computers and video game consoles, DOE developed multiple usage profiles to 

account for different usage patterns. DOE also examined usage profiles specific to commercial 

users for digital cameras, golf cars, professional-grade power tools, and two-way radios. DOE 

then calculated a weighted-average usage profile for each of these applications based on an 

estimated distribution of user types. It is these weighted-average usage profiles that were used in 

subsequent analyses. 

Table 7.7 Generic EPS Usage Profiles 

INFREQUENTLY USED (APPLICATION IS MOSTLY TURNED OFF) 

EPS 

Mode 

Application State Percent of Nameplate Output 

Power 

Time per Week 

(hours) 

Active 

Operating 60% 5 

Idle 2% 3 

Off 1% 160 

No-load Disconnected from 

EPS 

- 0 

Unplugged Disconnected from 

EPS 

- 0 

INFREQUENTLY USED (EPS IS MOSTLY UNPLUGGED) 

EPS 

Mode 

Application State Percent of Nameplate Output 

Power 

Time per Week 

(hours) 

Active 

Operating 60% 5 

Idle 2% 3 

Off 1% 0 

No-load Disconnected from 

EPS 

- 0 

Unplugged Disconnected from 

EPS 

- 160 

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ALWAYS ACTIVE (APPLICATION IS ALWAYS PLUGGED IN AND OPERATING) 

EPS 

Mode 

Application State Percent of Nameplate Output 

Power 

Time per Week 

(hours) 

Active Operating 60% 168 

No-load Disconnected from 

EPS 

- 0 

Unplugged Disconnected from 

EPS 

- 0 

MOSTLY NO-LOAD 

EPS 

Mode 

Application State Percent of Nameplate Output 

Power 

Time per Week 

(hours) 

Active Operating 60% 21 

Idle 2% 21 

No-load Disconnected from 

EPS 

- 126 

Unplugged Disconnected from 

EPS 

- 0 

MOSTLY NO-LOAD AND UNPLUGGED 

EPS 

Mode 

Application State Percent of Nameplate Output 

Power 

Time per Week 

(hours) 

Active Operating 60% 21 

Idle 2% 21 

No-load Disconnected from 

EPS 

- 63 

Unplugged Disconnected from 

EPS 

- 63 

Table 7.8 Generic EPS Usage Profile for a BC Application 

[hours/day] [#/day] 

BC Usage Profile BC 

Active 

BC 

Maintenance 

No 

Battery Unplugged Off Charges 

2 Charges per week 1.4 6.1 8.5 8 0 2/7 

EPS Usage Profile Active1 Active2 No-load Unplugged - -

2 Charges per week 1.4 6.1 8.5 8 - -

7.1.6 External Power Supply Unit Energy Consumption Values 

DOE calculated UEC at each CSL for EPSs associated with each application. These 

application-level UECs are inputs to the LCC analysis, which is conducted on each 

representative unit. 

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For each application, DOE selected an EPS nameplate output power that was typical 

based on a market survey of common applications (see BCEPS_Master_Survey.xls for more 

details). Based on this information, DOE then assigned each application to the representative unit 

that best matched the nameplate output power of the application’s EPS. Table 7.9 shows how 

applications were grouped based on nameplate output power. Some applications are common to 

more than one representative unit. Some notebook computers, for example, are shipped with 120 

watt EPSs while others are shipped with 60 watt EPSs. Applications with wide ranging EPS 

nameplate output powers were split into two or more groups as appropriate. 

Table 7.9 External Power Supply Representative Unit and associated Power Output range 

Representative 

Unit 

Nameplate Output 

Power 

Nameplate 

Output Voltage 

Range of 

Nameplate Output Powers 

[W] [V] [W] 

1 2.5 5 0-10.25 

2 18 12 10.26-39 

3 60 15 40-90 

4 120 19 91-250 

Once EPSs were sorted into these four groups, DOE calculated UEC values of each 

application using the nameplate output power of the representative unit based on the usage 

profile and loading points specific to the application. In this way, DOE could ensure that the 

LCC analysis weighed the incremental costs for an EPS of a given output power with the energy 

cost savings for an EPS with that same output power. Because the EPS LCC samples units at the 

application level, this methodology further ensures that each application’s unique usage profile 

and loading points are considered in the calculation. The sections that follow examine each 

representative unit in more detail. 

DOE also calculated weighted-average UECs for each unit of analysis in the NIA. 

Application shipments were used as weights. Table 7.10 shows these shipment-weighted average 

UECs for AC-DC basic voltage EPSs (product class A1) and for product classes A2, A3, and A4. 

DOE did not develop cost estimates for product classes A2, A3, and A4 (the scaled product 

classes) and instead borrowed cost and efficiency data from product class A1 for these classes. 

Specifically, DOE assumed that all products in A2 and A4 had nameplate output power of 2.5 W 

while products in A3 had nameplate output power of 18 W. In this way, DOE was able to ensure 

an appropriate cost/efficiency relationship in the NIA. 

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Table 7.10 External Power Supply Unit Energy Consumption (kWh/yr) 

Class ID 

Nameplate 

Output Power 

(W) 

CSL 0 CSL 1 CSL 2 CSL 3 CSL 4 

A1 

0-10.25 3.8 2.5 1.9 1.7 1.6 

10.26-39 15.5 11.8 9.7 7.9 6.6 

40-90 11.7 10.3 8.7 7.3 5.4 

91-250 19.4 16.8 14.2 13.6 9.4 

A2 All 2.4 1.5 1 0.8 0.7 

A3 All 15.7 12.0 9.9 8.0 6.7 

A4 All 8.8 5.8 5.0 4.4 4.3 

7.1.6.1 Product Class A1: Basic Voltage AC/DC Class A External Power Supplies 

Product class A1 is the largest EPS product class with over 200 million units shipped in 

2008. Four representative units, with nameplate output powers of 2.5, 18, 60, and 120 W were 

identified and analyzed for this product class. Effectively, this class has been subdivided into 

four segments, and every EPS in this class has been assigned to one of the four segments based 

on its nameplate output power. 

Cordless phones and answering machines (which DOE assumes also have a cordless 

phone) make up the majority of units in the segment associated with the 2.5 watt representative 

unit. Cordless phone and answering device EPSs are always in EPS active mode. UECs for each 

of the top five applications in this segment are shown in Table 7.11. 

Table 7.11 Product Class A1 – 2.5 Watt Representative Unit 

Top Applications by 

Shipments 

Shipments CSL 0 CSL 1 CSL 2 CSL 3 CSL 4 

(Units) (kWh/year) 

Answering Machines 20,175,000 5.0 3.3 2.8 2.5 2.4 

Cordless Phones 19,151,000 5.0 3.3 2.8 2.5 2.4 

Mobile Phones 13,140,000 2.6 1.6 1.1 0.9 0.8 

Portable Video Game 

Systems 

10,884,000 2.9 1.8 

0.8 

0.7 0.4 

In-Vehicle GPS 7,660,000 0.2 0.1 0.1 0.1 0.1 

Other Applications 5,217,000 - - - -

Weighted Average - 3.8 2.5 1.9 1.7 1.6 

Notes: Includes all AC/DC basic voltage Class A EPSs with nameplate output power up to 10.25 watts. 

LAN equipment makes up the majority of units in the segment associated with the 

18 watt representative unit. Because LAN equipment is always on, energy use is also relatively 

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high. DOE performed loading point tests on two pieces of LAN equipment. Both units consumed 

the same amount of energy whether they were transmitting or idle. UECs for each of the top five 

applications in this segment are shown in Table 7.12. 

Table 7.12 Product Class A1 – 18 Watt Representative Unit 

Top Applications by 

Shipments 

Shipments CSL 0 CSL 1 CSL 2 CSL 3 CSL 4 

(Units) (kWh/year) 

LAN Equipment 27,581,000 22.6 17.6 14.7 12.2 10.3 

VoIP Adapters 8,845,000 6.1 4.0 3.0 2.0 1.5 

Digital Picture 

Frames 

7,472,000 29.9 23.2 

19.4 

16.1 13.6 

Portable DVD 

Players 

7,140,000 1 0.7 

0.6 

0.5 0.4 

MP3 Speaker Docks 7,012,000 5.8 3.8 2.8 1.8 1.3 

Other Applications 8,671,000 - - - -

Weighted Average - 15.5 11.8 9.7 7.9 6.6 

Notes: Includes all AC/DC basic voltage Class A EPSs with nameplate output power between 10.25 and 39 watts. 

A majority of EPSs power notebook computers in both the third and fourth segments, 

which are associated with the 60 and 120 watt representative units, respectively. DOE considered 

two user types for notebook computers based on a report by the Natural Resources Defense 

Council.1 The ―road warrior‖ usage profile has significant unplugged time whereas the ―desktop

replacement‖ profile has very little unplugged time and more time in operating modes. DOE 

incorporated another active-mode state into the notebook profiles by incorporating time playing a 

DVD.2 

Video game consoles are the second most common application in the third segment. DOE 

defined two usage profiles for this application, one for a light user and one for a heavy user. The 

usage profiles were based on in-home usage audits of video game consoles conducted by The 

Nielsen Company in 2006. 3 DOE assumed 80 percent of users are light users and 20 percent are 

heavy users. DOE also incorporated DVD usage for video game consoles. DOE estimated that 

DVD usage did not vary among user types, and that one-third of video game consoles would be 

used as a DVD player. As part of the determination analysis, DOE identified loading points for 

the Xbox 360, which uses a non-Class A EPS. DOE applied these same loading points to video 

game consoles with Class A EPSs. UECs for the four applications in the third segment and the 

two applications in the fourth segment are shown in Table 7.13 and Table 7.14, respectively. 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

Table 7.13 Product Class A1 – 60 Watt Representative Unit 

Top Applications by 

Shipments 

Shipments CSL 0 CSL 1 CSL 2 CSL 3 CSL 4 

(Units) (kWh/year) 

Notebooks 30,225,000 10.9 9.7 8.1 6.8 5.0 

Video Game 

Consoles 

13,512,000 13.4 11.9 

9.9 

8.3 6.1 

Ink Jet Imaging 

Equipment 

9,339,000 11.2 12.0 

10.5 

9.1 6.6 

Netbooks 3,700,000 8.9 7.9 6.5 5.4 3.9 

Weighted Average - 11.7 10.3 8.7 7.3 5.4 

Notes: Includes all AC/DC basic voltage Class A EPSs with nameplate output power between 40 and 89 watts. 

Table 7.14 Product Class A1 – 120 Watt Representative Unit 

Top Applications by 

Shipments 

Shipments CSL 0 CSL 1 CSL 2 CSL 3 CSL 4 

(Units) (kWh/year) 

Notebooks 10,075,000 19.3 16.7 14.1 13.4 9.4 

LED Monitors 160,000 28.6 24.7 21.1 20.1 14.0 

Weighted Average - 19.4 16.8 14.2 13.6 9.4 

Notes: Includes all AC/DC basic voltage Class A EPSs with nameplate output between 90 and 250 watts. 

7.2 BATTERY CHARGERS 

This section describes battery charger modes, how UEC is calculated, and results for each 

product class. 

7.2.1 Battery Charger Modes 

For the purposes of calculating energy consumption, DOE considers a BC to always be in 

one of the following five states, which are also discussed in chapter 3: 

Active Mode: The DOE test procedure for BCs defines active mode as the condition 

in which the battery charger is connected to a power source; a battery is attached to 

the charger; and the battery charger is charging a depleted battery, equalizing its cells, 

or, ―performing other one-time or limited-time functions necessary for bringing the 

battery to the fully charged state.‖ (42 U.S.C. 6295(gg)(1)(A)(i)) 

Maintenance Mode: The DOE test procedure for BCs defines maintenance mode as 

the condition in which the battery charger is connected to mains power and the 

battery is fully charged, but is still connected to the charger. 

Standby Mode or No-Battery Mode: The DOE test procedure for BCs defines nobattery mode as the condition in which the battery charger is connected to mains 

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power and no battery is attached to the charger. DOE revised its BC test procedure to 

define standby mode as equivalent to no-battery mode for BCs. (74 FR 13318) 

Off Mode: For BCs, off mode is the condition in which the charger is connected to 

mains power, the charger is not connected to the battery, and all switches on the 

device are in the off position. 

Unplugged: The battery charger is disconnected from mains power. No energy is 

consumed in this mode. 

7.2.2 Battery Charger Usage Profiles 

The BC usage profiles DOE used in the preliminary analysis made use of the following 

measures: 

(1) Equivalent Charges per Day: The number of full charges completed in a day. This is 

the product of number of the frequency of charging (charges per day divided and days 

per week) and the depth of discharge of each charge. An application charged once per 

week from 100 percent depth of discharge would have 1/7 charges per day. 

(2) Total Time in Active and Maintenance Mode: The sum of time spent in active and 

maintenance modes over 24 hours. 

(3) Time in No-Battery (Standby) Mode: The time per day spent in no-battery mode. 

(4) Time in Off Mode: The time per day spent in off mode. 

(5) Time Unplugged: The time per day spent unplugged. 

Because usage of a BC is tied to usage of the application, DOE gathered usage profiles 

for a variety of applications. DOE received a number of BC-specific usage profiles from PG&E 

which it incorporated into its analysis. (DOCKET # 30) Where usage data were lacking, DOE 

assigned the application a generic usage profile. The generic BC usage profiles DOE used in the 

preliminary analysis are shown in Table 7.15. 

Application usage depends strongly on the individual user. For most applications, DOE 

assigned a single usage profile to represent all users. For some applications, DOE developed 

multiple usage profiles to account for different users. DOE then calculated a weighted-average 

usage profile based on an estimated distribution of user types. Usage profiles for each application 

are detailed in appendix 7A. 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

Table 7.15 Generic Battery Charger Usage Profiles 

Description 

Active + 

Maintenance 

No 

Battery 

(Standby) 

Unplugged Off Charges 

Source 

Hours per Day Number 

per Day 

All 

Maintenance 24.0 0 0 0 1/50 

PG&E for 

emergency 

backup systems 

Mostly 

Maintenance 23.5 0.5 0 0 1/7 

Based on PG&E 

for electric 

housewares 

1 Charge per 

week (mostly 

unplugged) 

1.0 0 23.0 0 1/7 DOE estimate 

2 Charges per 

week 7.5 8.5 8.0 0 2/7 PG&E for MP3 player 

5 Charges per 

week 6.0 7.0 11.0 0 5/7 PG&E for mobile phone 

7 Charges per 

week - light 

use 

21.8 2.2 0 0 1 

Based on PG&E 

for cordless 

phone 

7 Charges per 

week - heavy 

use 

12.0 12.0 0 0 1 PG&E for 

wheelchair 

Application usage profiles were then weighted by application shipments to calculate a 

shipments-weighted average usage profile for each product class, shown in Table 7.16. 

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Table 7.16 BC Shipments-Weighted Average Usage Profiles 

BC Product 

Class Active + 

Maintenance 

No Battery 

(Standby) Unplugged Off Charges 

Hours per Day Number per 

Day 

1 23.9 0.1 0 0 0.26 

2 9.7 5.0 9.4 0 0.58 

3 5.6 0.2 18.1 0.1 0.22 

4 16.8 0.3 6.9 0.1 0.88 

5 7.7 0.5 15.8 0 0.55 

6 15.4 8.6 0 0 0.46 

7 7.7 8.1 8.1 0 0.36 

8 6.5 7.5 10.1 0 0.43 

9 1.1 0.1 22.8 0 0.15 

10 24.0 0 0 0 0 

Note: Usage times may not sum to exactly 24 hours due to rounding. 

7.2.3 Calculating Battery Charger Energy Use 

7.2.3.1 General Energy Use Methodology 

UEC represents the annual energy consumption of a battery charger. To accurately 

represent usage in the field, DOE calculates UEC by combining a usage profile with the energy 

performance characteristics for each energy-consuming mode. For BCs, UEC over a given time 

period is the sum of: 

(1) Charge Energy Consumption over time: The product of the number of 24-hour charge 

cycles and the 24-hour charge cycle energy consumption measured in the test 

procedure, less battery energy; 

(2) Maintenance Mode Energy Consumption: The product of the time spent in 

maintenance mode and the power drawn while in maintenance mode; 

(3) No Battery (Standby) Mode Energy Consumption: The product of the time spent in 

standby mode and the power drawn while in standby mode; and 

(4) Off Mode Energy Consumption: The product of the time spent in off mode and the 

power drawn while in off mode. 

Charge Energy Consumption: Given the 24-hour charge and maintenance energy 

measurement at each CSL from the test procedure, E24, DOE calculated charge energy 

consumption, ECharge, by subtracting battery energy, EBatt and excess maintenance energy, over 

the measurement period. Excess maintenance energy is calculated as maintenance power, PMaint, 

multiplied by time beyond that spent actively charging, tCharge. Therefore: 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ECharge = E24 – EBatt – (PMaint × (24 – tCharge)) 

An example ECharge calculation is illustrated in Figure 7.4. In this case, E24 is represented 

by the area under the blue curve, and includes the energy lost in the BC during charge, as well as 

the battery energy and any excess maintenance mode losses. The excess maintenance mode 

energy, represented by the area under the red curve, is (PMaint × (24 – tCharge)), or in this example, 

approximately 1.2 W × (24 h – 7.5 h) = 19.8 Wh. (W) 

0 3 6 9 12 15 18 21 24 

Charge and Maintenance 

Mode Power 

Maintenance Mode Power 

Charge Energy 

EBatt 

Figure 7.4 Calculating Charge Energy Consumption from 24-Hour Energy 

Charge energy over the course of a day, ECharge Day is the product of ECharge and the number 

of charges per day, n: 

Day ECharge = ECharge × n 

Maintenance Mode Energy Consumption: Maintenance mode energy, EMaint, is calculated 

by multiplying PMaint by the daily amount of time the BC is plugged in and attached to the 

battery, tActive + tMaint , but not charging it. The time the BC is plugged in and attached to the 

battery and the charges per day are determined by the usage profile, while the time per charge, 

tCharge, is dictated by the charge rate of the BC itself: 

EMaint = PMaint × (tActive + tMaint – (tCharge × n)) 

No Battery (Standby) Mode Energy Consumption: No battery (standby) energy, ENoBatt is 

simply: 

ENoBatt = PNoBatt × tNoBatt 

Off Mode Energy Consumption: Likewise, off-mode energy, EOff is: 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

EOff = POff × tOff 

Given energy consumption in each mode, the complete annual unit energy consumption 

calculation is represented as: 

UEC = 365 × ([n × (E24 – EBatt – PMaint × (24 – tCharge))] + [PMaint × (tActive + tMaint – 

(tCharge × n)] + [PNoBatt × tNoBatt] + [POff × tOff]) 

Or more simply, 

UEC = 365 × (ECharge Day + EMaint + ENoBatt + EOff) 

7.2.3.1 Modified Energy Use Methodology for Some Slow Chargers 

In some cases the methodology described above had to be modified because the 

performance of the BC at a particular CSL did not fit with the application-specific usage profile. 

For example, mobile phones (product class 2) typically use fast chargers and their usage profile 

reflects a fast charging BC. However, CSL 0 in product class 2 is based on a slow charger 

typically used with small tools and cordless phones. The mobile phone usage profile does not 

allow enough time for the BC at CSL 0 to make a complete charge. 

Because each CSL has an underlying charge time associated with it, a problem arises if it 

will take longer to charge the battery than the usage profile will allow. That is, 

CSL tCharge × n > tActive + tMaint. 

This problem is illustrated by Figure 7.5. BCs at CSLs 1, 2, and 3 complete their charges 

within the time allotted by the usage profile whereas a BC at CSL 0 takes additional time to 

complete the charge. 

Time Plugged In and Connected to Battery 

Charging Maintenance 

CSL1 

CSL2 

CSL3 

CSL0 

Figure 7.5 Active and Maintenance Time 

In order to correctly account for charge energy consumption, it is necessary to allow the 

BC enough time to complete the charge. To account for the extra time needed, DOE allowed the 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BC to complete its charge by reducing the time spent unplugged or in no battery mode. The 

resultant energy consumption in this case is calculated as follows. 

Charge Energy Consumption (as before): 

ECharge = E24 – EBatt – (PMaint × (24 – tCharge)) 

ECharge Day = ECharge × n 

Maintenance Mode Energy Consumption: Again, this modified methodology was used in 

cases when the charge time of some slow BCs exceeded the time allocated under the given usage 

profile for both active and maintenance modes (tActive + tMaint). No time remained for 

maintenance mode, resulting in an EMaint of zero. 

If PMaint × ((tActive + tMaint) – (tCharge × n)) ≤ 0
	

Then EMaint = 0
 

No Battery (Standby) Mode Energy Consumption: If the charge time of a slow BC 

exceeds its allocated time in active and maintenance modes, that excess time must be accounted 

for. DOE deducted the extra time needed to complete a charge from the time spent unplugged 

(with zero energy consumption). If the unplugged time provided by the usage profile was 

insufficient to make up the excess, DOE deducted the time from the no-battery time. 

CSL If tCharge × n + tNoBatt ≤ 24 h
 

Then ENoBatt = PNoBatt × tNoBatt
 

If tCharge 

CSL × n + tNoBatt > 24 h
 

Then ENoBatt = PNoBatt × (24 h - tCharge 

CSL × n)
 

Since none of BC usage profiles spent any time in off mode, DOE did not adjust the off 

time. 

Off Mode Energy Consumption (as before): 

EOff = POff × tOff 

Although the use of the modified methodology required a case-by-case modification of 

the usage profile, DOE considers this appropriate because usage profiles represent only the 

average or typical use of a BC with a given application. There will be departures from the usage 

profiles, and using the above methodology DOE was able extend its analytical framework to the 

less typical uses while continuing to model expected user behavior—i.e., if the charger takes 

longer to charge than expected, the user will leave it plugged in longer. 

7.2.4 Battery Charger Unit Energy Consumption Values 

DOE expresses each CSL in terms of annual unit energy consumption based on the weighted 

average usage profiles described in section 7.2.2. In order to accurately represent the variety of 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

usage that occurs in the field, it is necessary to combine each application-specific usage profile 

with mode-specific performance characteristics. DOE took the UECs and the mode-specific 

performance characteristics - E24, EBatt, PMaint , tCharge, PNoBatt, and POff, presented in chapter 5. 

These values can be found in Table 7.17 and Table 7.18. DOE then combined these 

characteristics with application-level usage to calculate application-level UECs. 

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EERE-2008-BT-STD-0005 COMMENT 31
Table 7.17 Mode-Specific Performance Characteristics – Manufacturer Data 

Product 

Class CSL 

Rated 

Battery 

Energy 

(Wh) 

24-Hour 

Charge 

Energy 

(Wh) 

Est. Time 

in Active 

(h) 

Maint. 

Mode 

Power 

(W) 

NoBattery 

Mode 

Power 

(W) 

Off Mode 

Power 

(W) 

0 1.5 26.7 24.0 1.2 0.5 0.0 

1 1.5 19.3 24.0 0.8 0.4 0.0 1 2 1.5 10.8 24.0 0.4 0.2 0.0 

3 1.5 5.9 24.0 0.2 0.1 0.0 

2 

0 

1 

2 

3.0 

3.0 

3.0 

41.1 

31.3 

9.8 

22.0 

14.5 

6.9 

1.8 

1.1 

0.4 

0.7 

0.4 

0.1 

0.0 

0.0 

0.0 

3 

0 

1 

2 

10.0 

10.0 

10.0 

91.3 

65.7 

21.4 

16.1 

10.3 

1.1 

4.7 

2.5 

0.2 

1.0 

0.6 

0.2 

0.0 

0.0 

0.0 

4 

0 

1 

2 

20.0 

20.0 

20.0 

142.9 

57.4 

42.5 

13.0 

1.5 

1.0 

3.4 

1.0 

0.7 

1.2 

0.5 

0.2 

0.0 

0.0 

0.0 

0 800.0 1830.0 13.0 10.0 10.0 0.0 

1 800.0 1620.0 12.0 10.0 10.0 0.0 5 2 800.0 1301.1 8.0 0.1 0.1 0.0 

3 800.0 1175.1 8.0 0.0 0.0 0.0 

0 384.0 720.8 20.0 5.0 1.2 0.0 

1 384.0 620.0 16.0 0.5 0.5 0.0 6 2 384.0 524.6 16.0 0.3 0.3 0.0 

3 384.0 491.3 8.0 0.0 0.0 0.0 

0 3750.0 5904.7 8.0 3.6 3.7 0.0 

1 3750.0 5607.5 8.0 3.3 3.2 0.0 7 2 3750.0 5235.9 8.0 2.9 2.6 0.0 

3 3750.0 4864.3 8.0 2.6 2.0 0.0 

8 

0 

1 

2 

2.0 

2.0 

2.0 

14.3 

9.4 

6.4 

3.0 

3.0 

3.0 

0.3 

0.2 

0.1 

-

-

-

0.0 

0.0 

0.0 

9 

0 

1 

2 

3.6 

3.6 

3.6 

36.5 

23.3 

15.4 

3.0 

3.0 

3.0 

0.5 

0.2 

0.1 

-

-

-

0.0 

0.0 

0.0 

0 70.0 0 24.0 2.2 - 0.0 

1 70.0 0 24.0 0.7 - 0.0 10 2 70.0 0 24.0 0.5 - 0.0 

3 70.0 0 24.0 0.2 - 0.0 

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Table 7.18 Mode-Specific Performance Characteristics – Test and Teardown Data 

Product 

Class CSL 

Battery 

Energy 

(Wh) 

24-Hour 

Charge 

Energy 

(Wh) 

Est. Time 

in Active 

(h) 

Maint. 

Mode 

Power 

(W) 

NoBattery 

Mode 

Power 

(W) 

Off Mode 

Power 

(W) 

2 1 

2 

2.9 

2.8 

33.5 

8.8 

21.4 

2.6 

1.4 

0.1 

0.3 

0.1 

0.0 

0.0 

4 

0 

1 

2 

16.3 

13.4 

22.9 

167.5 

52.6 

44.6 

0.6 

0.9 

2.7 

5.9 

1.4 

0.6 

2.2 

1.4 

0.1 

0.0 

0.0 

0.0 

5 0 

1 

830.7 

762.1 

2036.9 

1647.3 

12.8 

15.9 

21.2 

11.9 

20.1 

11.6 

0.0 

0.0 

10 0 

1 

78.0 

51.7 

149.9 

93.0 

24.0 

17.3 

2.2 

0.7 

N/A 

N/A 

0.0 

0.0 

DOE calculated UEC at each CSL for each application in each product class. These 

application-level UECs are inputs to the LCC. Then, for each product class, DOE calculated the 

shipment-weighted average of the application-level UECs. These UECs are used in the NIA. 

DOE derived one set of UECs from manufacturer-supplied cost-efficiency data and another from 

test & teardown data. The former are shown in Table 7.19 and the latter in Table 7.20. The 

sections that follow examine each product class in more detail and include the top applicationlevel UECs. UECs for all applications can be found in appendix 7B. 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

Table 7.19 Battery Charger Unit Energy Consumption by Product Class based on 

Manufacturer-Supplied Data (kWh/yr) 

Battery 

Energy 

Battery 

Voltage 

Class 

ID 

CSL 0 

(kWh/yr) 

CSL 1 

(kWh/yr) 

CSL 2 

(kWh/yr) 

CSL 3 

(kWh/yr) 

ACDC 

<100 

Wh 

Inductive 

Connection 1 10.0 7.0 3.5 1.5 

<4 V 2 10.0 6.0 1.2 -

4<10 V 3 10.0 5.4 1.0 -

≥10 V 4 39.4 10.5 6.1 -

100–

3000 

Wh 

<20 V 5 202.3 158.4 100 75.0 

≥20 V 6 69.3 41.9 25.0 18.0 

>3000 

Wh All 7 290 250 200 150 

DC-DC <9 V Input 8 1.5 0.9 0.6 -

≥9 V Input 9 1.3 0.8 0.5 -

AC-AC 

AC Output 

from 

Battery 

10 19.6 6.4 4.0 1.5 

Table 7.20 Battery Charger Unit Energy Consumption by Product Class based on Test and 

Teardown Data (kWh/yr) 

Battery 

Energy 

Battery 

Voltage 

Class 

ID 

CSL 0 

(kWh/yr) 

CSL 1 

(kWh/yr) 

CSL 2 

(kWh/yr) 

CSL 3 

(kWh/yr) 

ACDC 

<100 

Wh 

Inductive 

Connection 1 - - - -

<4 V 2 - 7.4 1.2 -

4<10 V 3 - - - -

≥10 V 4 39.4 10.5 6.1 -

100–

3000 

Wh 

<20 V 5 232.7 179.3 - -

≥20 V 6 - - - -

>3000 

Wh All 7 - - - -

DC-DC <9 V Input 8 - - - -

≥9 V Input 9 - - - -

AC-AC 

AC Output 

from 

Battery 

10 19.6 6.4 - -

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7.2.4.1 Battery Charger Product Class 1: Inductive Connection, <100 Wh 

This category includes rechargeable toothbrushes and water jets. DOE applied the same 

usage profile to each application. These products employ a cradle charger and are always 

plugged in. UECs for each of the two applications in this product class are shown in Table 7.21. 

Table 7.21 Battery Charger Product Class 1 – based on Manufacturer-Supplied Data 

Top Applications by 

Shipments 

Shipments CSL0 CSL1 CSL2 CSL3 

(Units) (kWh/year) (kWh/year) (kWh/year) (kWh/year) 

Rechargeable 

Toothbrushes 

4,868,000 10.0 7.0 3.5 1.5 

Rechargeable Water 

Jets 

487,000 10.0 7.0 3.5 1.5 

Weighted Average - 10.0 7.0 3.5 1.5 

Notes: Assumes a battery voltage of 1.2 V and battery energy of 0.8 Wh. 

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7.2.4.2 Battery Charger Product Class 2: <4 V Battery, <100 Wh 

Mobile phones dominate product class 2 with over 100 million unit shipments. DOE 

based its usage profile for mobile phones on data provided by PG&E (Docket# 30). UECs for 

each of the top five applications in this product class are shown for both manufacturer and test & 

teardown engineering inputs in Table 7.22 and Table 7.23, respectively. 

Table 7.22 Battery Charger Product Class 2 – based on Manufacturer-Supplied Data 

Top Applications by 

Shipments 

Shipments CSL0 CSL1 CSL2 CSL3 

(Units) (kWh/year) (kWh/year) (kWh/year) (kWh/year) 

Mobile Phones 105,120,000 10.8 5.8 0.7 -

Answering Machines 20,175,000 13.6 9.6 2.5 -

Cordless Phones 19,151,000 13.6 9.6 2.5 -

Portable Video 

Game Systems 

13,777,000 6.6 4.6 1.2 -

Digital Cameras 10,879,000 1.4 0.8 0.1 -

Other Applications 37,119,000 - - - -

Weighted Average - 10.0 6.0 1.2 -

Notes: Assumes a battery voltage of 3.6 V and battery energy of 3.0 Wh. 

Table 7.23 Battery Charger Product Class 2 – based on Test & Teardown Data 

Top Applications by 

Shipments 

Shipments CSL0 CSL1 CSL2 CSL3 

(Units) (kWh/year) (kWh/year) (kWh/year) (kWh/year) 

Mobile Phones 105,120,000 - 7.7 1.2 -

Answering Machines 20,175,000 - 10.7 1.8 -

Cordless Phones 19,151,000 - 10.7 1.8 -

Portable Video 

Game Systems 

13,777,000 - 4.4 0.8 -

Digital Cameras 10,879,000 - 1.0 0.2 -

Other Applications 37,119,000 - - - -

Weighted Average - - 7.4 1.2 -

Notes: Assumes a battery voltage of 3.6 V and battery energy of 3.0 Wh. 

7.2.4.3 Battery Charger Product Class 3: 4-10 V Battery, <100 Wh 

Product class 3 includes a range of products including portable DVD players, toy ride-on 

vehicles, and power tools. UECs for each of the top five applications in this product class are 

shown in Table 7.24. 

Table 7.24 Battery Charger Product Class 3 – based on Manufacturer-Supplied Data 

Top Applications by Shipments CSL0 CSL1 CSL2 CSL3 

Shipments (Units) (kWh/year) (kWh/year) (kWh/year) (kWh/year) 

Portable DVD 

Players 

7,140,000 6.4 3.6 0.4 -

Camcorders 4,206,000 0.8 0.4 0.1 -

Toy Ride-On 3,548,000 11.3 5.5 2.0 -

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Vehicles 

RC Toys 2,100,000 2.3 1.1 0.4 -

DIY Power Tools 1,753,000 10.7 5.4 2.1 -

Other Applications 4,369,000 - - - -

Weighted Average - 10.0 5.4 1.0 -

Notes: Assumes a battery voltage of 7.2 V and battery energy of 10 Wh. 

7.2.4.4 Battery Charger Product Class 4: >10 V Battery, <100 Wh 

Notebook computers make up more than half of the unit shipments in BC product class 4. 

DOE examined two usage profiles for BCs – one with significant maintenance time to represent 

a ―desktop replacement‖ user, and one with significant unplugged time to represent a user that 

powers their notebook frequently from the battery. UECs for each of the top five applications in 

this product class are shown for both manufacturer and test & teardown engineering inputs in 

Table 7.25 and Table 7.26, respectively. 

Table 7.25 Battery Charger Product Class 4 – based on Manufacturer-Supplied Data 

Top Applications by 

Shipments 

Shipments CSL0 CSL1 CSL2 CSL3 

(Units) (kWh/year) (kWh/year) (kWh/year) (kWh/year) 

Notebooks 40,300,000 32.9 10.0 6.2 -

Professional Power 

Tools 

11,688,000 79.4 15.9 7.6 -

DIY Power Tools 5,259,000 20.5 5.8 3.1 -

Netbooks 3,700,000 33.1 10.1 6.1 -

Handheld Vacuums 2,797,000 32.7 9.8 6.5 -

Other Applications 6,014,000 - - - -

Weighted Average - 39.4 10.5 6.1 -

Notes: Assumes a battery voltage of 10.8 V and battery energy of 20 Wh. 

Table 7.26 Battery Charger Product Class 4 – based on Test & Teardown Data 

Top Applications by 

Shipments 

Shipments CSL0 CSL1 CSL2 CSL3 

(Units) (kWh/year) (kWh/year) (kWh/year) (kWh/year) 

Notebooks 40,300,000 45.5 11.6 5.7 -

Professional Power 

Tools 

11,688,000 26.3 9.0 9.9 -

DIY Power Tools 5,259,000 17.7 5.3 3.4 -

Netbooks 3,700,000 41.3 10.7 5.8 -

Handheld Vacuums 2,797,000 52.4 12.9 5.4 -

Other Applications 6,014,000 - - - -

Weighted Average - 39.4 10.5 6.1 -

Notes: Assumes a battery voltage of 10.8 V and battery energy of 20 Wh. 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

7.2.4.5 Battery Charger Product Class 5: <20 V Battery, 100-3,000 Wh 

Toy ride on vehicles make up the majority of shipments in product class 5. UECs for 

each of the four applications in this product class are shown for both manufacturer and test & 

teardown engineering inputs in Table 7.27 and Table 7.28, respectively. 

Table 7.27 Battery Charger Product Class 5 – based on Manufacturer-Supplied Data 

Top Applications by 

Shipments 

Shipments CSL0 CSL1 CSL2 CSL3 

(Units) (kWh/year) (kWh/year) (kWh/year) (kWh/year) 

Toy Ride-On Vehicles 1,774,000 235.4 179.2 127.7 95.9 

Marine/Automotive/RV 

Chargers 

500,000 103.3 99.1 10.6 7.3 

Portable O2 

Concentrators – Low 

Output 

50,000 48.0 36.5 26.1 19.6 

Portable O2 

Concentrators – High 

Output 

9,000 48.0 36.5 26.1 19.6 

Weighted Average - 202.3 158.4 100.0 75.0 

Notes: Assumes a battery voltage of 12 V and battery energy of 800 Wh. 

Table 7.28 Battery Charger Product Class 5 – based on Test & Teardown Data 

Top Applications by 

Shipments 

Shipments CSL0 CSL1 CSL2 CSL3 

(Units) (kWh/year) (kWh/year) (kWh/year) (kWh/year) 

Toy Ride-On Vehicles 1,774,000 248.4 201.7 - -

Marine/Automotive/RV 

Chargers 

500,000 198.2 116.2 - -

Portable O2 

Concentrators – Low 

Output 

50,000 50.5 41.1 - -

Portable O2 

Concentrators – High 

Output 

9,000 50.5 41.1 - -

Weighted Average - 232.7 179.3 - -

Notes: Assumes a battery voltage of 12 V and battery energy of 800 Wh. 

7.2.4.6 Battery Charger Product Class 6: ≥20 V Battery, 100-3,000 Wh 

Personal transportation equipment dominates product class 6. Most units are charged frequently 

and spend a significant amount of time in no-battery mode. DOE assumes users do not unplug 

BCs in product class 6. UECs for each of the five applications in this product class are shown in 

Table 7.29. 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

Table 7.29 Battery Charger Product Class 6 –based on Manufacturer-Supplied Data 

Top Applications by 

Shipments 

Shipments CSL0 CSL1 CSL2 CSL3 

(Units) (kWh/year) (kWh/year) (kWh/year) (kWh/year) 

Electric Scooters 250,000 65.9 39.4 23.5 16.8 

Mobility Scooters 192,000 85.3 61.6 36.7 27.4 

Lawn Mowers 182,000 45.3 8.8 5.3 2.1 

Wheelchairs 166,000 85.3 61.6 36.7 27.4 

Motorized Bicycles 150,000 65.9 39.4 23.5 16.8 

Weighted Average - 69.3 41.9 25.0 18.0 

Notes: Assumes a battery voltage of 36 V and battery energy of 384 Wh. 

7.2.4.7 Battery Charger Product Class 7: >3,000 Wh 

Golf cars have the highest battery energies of any application analyzed by DOE. They 

also have the only BCs DOE found with on/off switches. UECs for this application are shown in 

Table 7.30. 

Table 7.30 Battery Charger Product Class 7 – based on Manufacturer-Supplied Data 

Top Applications by 

Shipments 

Shipments CSL0 CSL1 CSL2 CSL3 

(Units) (kWh/year) (kWh/year) (kWh/year) (kWh/year) 

Golf Cars 214,000 290 250 200 150 

Notes: Assumes a battery voltage of 48 V and battery energy of 3,750 Wh. 

7.2.4.8 Battery Charger Product Class 8: DC-DC Chargers, <9 V Input 

The most common applications that employ USB power (or other 5 V input) are MP3 

players and mobile phones. DOE assumes these applications are charged a few times per week 

and spend a significant amount of time unplugged. UECs for each of the top five applications in 

this product class are shown in Table 7.31. 

Table 7.31 Battery Charger Product Class 8 – based on Manufacturer-Supplied Data 

Top Applications by 

Shipments 

Shipments CSL0 CSL1 CSL2 CSL3 

(Units) (kWh/year) (kWh/year) (kWh/year) (kWh/year) 

MP3 Players 39,358,000 1.3 0.8 0.5 -

Mobile Phones 26,280,000 2.0 1.1 0.7 -

Digital Cameras 2,720,000 0.3 0.2 0.1 -

Personal Digital 

Assistants 

1,779,000 0.9 0.5 0.3 -

Camcorders 1,402,000 0.1 0.1 0.0 -

Other Applications 286,000 - - - -

Weighted Average - 1.5 0.9 0.6 -

Notes: Assumes battery voltage of 3.6 V and battery energy of 2 Wh. 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

7.2.4.9 Battery Charger Product Class 9: DC-DC Chargers, ≥9 V Input 

In-vehicle GPSs are by far the most common applications with BCs charged by 12 V 

input. DOE assumes these units spend the majority of time unplugged; that is, disconnected from 

the car’s battery. While the car is running, these units are either in maintenance mode or 

charging. UECs for each of the five applications in this product class are shown in Table 7.32. 

Table 7.32 Battery Charger Product Class 9 – based on Manufacturer-Supplied Data 

Top Applications by 

Shipments 

Shipments CSL0 CSL1 CSL2 CSL3 

(Units) (kWh/year) (kWh/year) (kWh/year) (kWh/year) 

In-Vehicle GPS 15,320,000 1.2 0.8 0.5 -

Medical Nebulizers 90,000 9.3 5.7 3.4 -

Portable O2 

Concentrators – Low 

Output 

50,000 1.2 0.8 0.5 -

Flashlights and 

Lanterns 

50,000 2.9 1.4 0.7 -

Portable O2 

Concentrators –

High Output 

9,000 1.2 0.8 0.5 -

Weighted Average - 1.3 0.8 0.5 -

Notes: Assumes a battery voltage of 3.6 V and battery energy of 5 Wh. 

7.2.4.10 Battery Charger Product Class 10: AC-AC, AC Output from Battery 

Uninterruptible power supplies are the only application DOE identified in product class 

10. They are almost always in maintenance mode. UECs for this application are shown for both 

manufacturer and test & teardown engineering inputs in Table 7.33 and Table 7.34, respectively. 

Table 7.33 Battery Charger Product Class 10 – based on Manufacturer-Supplied Data 

Top Applications 

by Shipments 

Shipments CSL0 CSL1 CSL2 CSL3 

(Units) (kWh/year) (kWh/year) (kWh/year) (kWh/year) 

Uninterruptible 

Power Supplies 

6,900,000 19.6 6.4 4.0 1.5 

Weighted Average - 19.6 6.4 4.0 1.5 

Notes: Assumes a battery voltage of 12 V and battery energy of 70 Wh. 

Table 7.34 Battery Charger Product Class 10 – based on Test & Teardown Data 

Top Applications 

by Shipments 

Shipments CSL0 CSL1 CSL2 CSL3 

(Units) (kWh/year) (kWh/year) (kWh/year) (kWh/year) 

Uninterruptible 

Power Supplies 

6,900,000 19.6 6.4 - -

Weighted Average - 19.6 6.4 - -

Notes: Assumes a battery voltage of 12 V and battery energy of 70 Wh. 

7-31 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

References 

1 Natural Resources Defense Council. "Laptop Computers: How Much Energy Do They Use and How Much Energy
 

Can We Save?" August 2003.
 2 TIAX, LLC. "Energy Consumption by Consumer Electronics in U.S. Residences", Final Report to the Consumer
 

Electronics Association, January 2007.
 3

Nielsen Wireless and Interactive Services. "The State of the Console - Video Game Console Usage - Fourth Quarter
 

2006". 2007. 

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CHAPTER 8. LIFE-CYCLE COST AND PAYBACK PERIOD ANALYSES
 

TABLE OF CONTENTS 

8.1 INTRODUCTION ............................................................................................... 8-1
 

8.1.1 General Approach for Life-Cycle Cost and Payback Period Analyses ............... 8-1
 

8.1.2 Overview of LCC and PBP Inputs....................................................................... 8-4
 

8.2 LIFE-CYCLE COST INPUTS ............................................................................ 8-6
 

8.2.1 Definition ............................................................................................................. 8-6
 

8.2.2 Total Installed Cost Inputs................................................................................... 8-7
 

8.2.3 Operating Cost Inputs .......................................................................................... 8-8
 

8.2.4 Unit Energy Consumption ................................................................................... 8-9
 

8.2.5 Electricity Prices .................................................................................................. 8-9
 

8.2.6 Electricity Price Trend ....................................................................................... 8-10
 

8.2.7 Gasoline Prices and Trends................................................................................ 8-12
 

8.2.8 Lifetime.............................................................................................................. 8-13
 

8.2.9	 Discount Rate..................................................................................................... 8-14
 

8.2.9.1 Residential Discount Rate...................................................................... 8-14
 

8.2.9.2 Commercial Discount Rate .................................................................... 8-18
 

8.2.10 Product Energy Efficiency in the Base Case ..................................................... 8-21
 

8.2.11 Compliance Date of Standard ............................................................................ 8-22
 

8.3	 PAYBACK PERIOD INPUTS.......................................................................... 8-23
 

8.3.1	 Definition ........................................................................................................... 8-23
 

8.3.2	 Inputs.................................................................................................................. 8-23
 

8.3.3	 Rebuttable Presumption Payback Period ........................................................... 8-24
 

8.4	 LIFE-CYCLE COST AND PAYBACK PERIOD RESULTS.......................... 8-24
 

8.4.1	 Non-Class A External Power Supply Results.................................................... 8-25
 

8.4.2	 Class A External Power Supply Results ............................................................ 8-25
 

8.4.2.1 Base Case LCC Distributions (Manufacturer Data) .............................. 8-26
 

8.4.2.2 2.5W Regular AC/DC External Power Supplies (Manufacturer Data) . 8-28
 

8.4.2.3 18W Regular AC/DC External Power Supplies (Manufacturer Data) .. 8-30
 

8.4.2.4 60W Regular AC/DC External Power Supplies (Manufacturer Data) .. 8-32
 

8.4.2.5 120W Regular AC/DC External Power Supplies (Manufacturer Data) 8-34
 

8.4.3	 Battery Charger Results (Representative Units) ................................................ 8-36
 

8.4.3.1 Base Case LCC Distributions (Manufacturer Data) .............................. 8-37
 

8.4.3.2 Base Case LCC Distributions (Test/Teardown Data)............................ 8-40
 

8.4.3.3 Low Energy, Inductive Battery Chargers (Manufacturer Data) ............ 8-43
 

8.4.3.4 Low Energy, Inductive Battery Chargers (Test/Teardown Data).......... 8-45
 

8.4.3.5 Low Energy, Low Voltage Battery Chargers (Manufacturer Data) ...... 8-45
 

8.4.3.6 Low Energy, Low Voltage Battery Chargers (Test/Teardown Data) .... 8-47
 

8.4.3.7 Low Energy, High Voltage Battery Chargers (Manufacturer Data)...... 8-49
 

8.4.3.8 Low Energy, High Voltage Battery Chargers (Test/Teardown Data) ... 8-51
 

8.4.3.9 Medium Energy, Low Voltage Battery Chargers (Manufacturer Data) 8-53
 

8.4.3.10	 Medium Energy, Low Voltage Battery Chargers (Test/Teardown 

Data) 8-55
 

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8.4.3.11 High Energy Battery Chargers (Manufacturer Data)................. 8-57
 

8.4.3.12 High Energy Battery Chargers (Test/Teardown Data) .............. 8-59
 

8.4.3.13 Low Energy, AC Out Battery Chargers (Manufacturer Data)... 8-59
 

8.4.3.14 Low Energy, AC Out Battery Chargers (Test/Teardown Data) 8-61
 

8.4.4 Battery Charger Results (Scaled Product Classes) ............................................ 8-63
 

8.4.4.1 Base Case LCC Distributions (Manufacturer Data) .............................. 8-64
 

8.4.4.2 Summarized Life-Cycle Cost and Payback Period Results ................... 8-66
 

8.5 DETAILED RESULTS AND SENSITIVITY RUNS....................................... 8-67
 

LIST OF TABLES 

Table 8.1.1 Representative Units and Product Classes Analyzed in the LCC and PBP
 

Analyses........................................................................................................................... 8-3
 

Table 8.1.2 Scaled Battery Charger Product Classes Analyzed in the LCC and PBP
 

Table 8.2.6 Shares and Interest or Return Rates Used for Household Debt and Equity
 

Table 8.2.9 Estimated Share of BC and EPS Purchases by Ownership Category in 

Table 8.2.11 Base Case Energy Efficiency Market Shares for Class A External Power 

Table 8.2.12 Base Case Energy Efficiency Market Shares for Battery Chargers in 2013 8­

Table 8.2.13 Base Case Energy Efficiency Market Shares for Scaled Battery Charger 

Table 8.4.1 LCC and PBP Results for 2.5W Regular AC/DC External Power Supplies 

Table 8.4.2 LCC and PBP Results for 18W Regular AC/DC External Power Supplies 

Table 8.4.3 LCC and PBP Results for 60W Regular AC/DC External Power Supplies 

Table 8.4.4 LCC and PBP Results for 120W Regular AC/DC External Power Supplies 

Table 8.4.5 LCC and PBP Results for Low Energy, Inductive Battery Chargers 

Analyses........................................................................................................................... 8-3
 

Table 8.1.3 Summary Information of Inputs for the Life-Cycle Cost and Payback 

Period Analyses ............................................................................................................... 8-6
 

Table 8.2.1 Inputs for Operating Costs........................................................................... 8-8
 

Table 8.2.2 Electricity Prices by Census Division, 2009.............................................. 8-10
 

Table 8.2.3 Average Percentage Shares of Household Debt and Equity Types ........... 8-15
 

Table 8.2.4 Average Nominal and Real Interest Rates for Household Debt Classes ... 8-16
 

Table 8.2.5 Average Nominal and Real Interest Rates for Household Equity Types .. 8-17
 

Types.............................................................................................................................. 8-17
 

Table 8.2.7 Variables Used to Estimate Company Discount Rates.............................. 8-19
 

Table 8.2.8 Real Discount Rates by BC and EPS Ownership Category....................... 8-20
 

Commercial Sector......................................................................................................... 8-21
 

Table 8.2.10 Average Real Discount Rate by Sector.................................................... 8-21
 

Supplies in 2013............................................................................................................. 8-22
 

22
 

Product Classes in 2013................................................................................................. 8-22
 

(Manufacturer Data)....................................................................................................... 8-30
 

(Manufacturer Data)....................................................................................................... 8-32
 

(Manufacturer Data)....................................................................................................... 8-34
 

(Manufacturer Data)....................................................................................................... 8-36
 

(Manufacturer Data)....................................................................................................... 8-45
 

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Table 8.4.6 LCC and PBP Results for Low Energy, Low Voltage Battery Chargers 

(Manufacturer Data)....................................................................................................... 8-47
 

Table 8.4.7 LCC and PBP Results for Low Energy, Low Voltage Battery Chargers 

Table 8.4.8 LCC and PBP Results for Low Energy, High Voltage Battery Chargers 

Table 8.4.9 LCC and PBP Results for Low Energy, High Voltage Battery Chargers 

Table 8.4.10 LCC and PBP Results for Medium Energy, Low Voltage Battery Chargers 

Table 8.4.11 LCC and PBP Results for Medium Energy, Low Voltage Battery Chargers 

Table 8.4.12 LCC and PBP Results for High Energy Battery Chargers (Manufacturer 

Table 8.4.13 LCC and PBP Results for Low Energy, AC Out Battery Chargers 

Table 8.4.14 LCC and PBP Results for Low Energy, AC Out Battery Chargers 

Table 8.4.15 LCC and PBP Results for Low Energy, Medium Voltage Battery Chargers 

Table 8.4.16 LCC and PBP Results for Medium Energy, High Voltage Battery Chargers 

Table 8.4.17 LCC and PBP Results from DC-DC, <9V Input Battery Chargers 

Table 8.4.18 LCC and PBP Results from DC-DC, ≥9V Input Battery Chargers 

(Test/Teardown Data) .................................................................................................... 8-49
 

(Manufacturer Data)....................................................................................................... 8-51
 

(Test/Teardown)............................................................................................................. 8-53
 

(Manufacturer Data)....................................................................................................... 8-55
 

(Test/Teardown Data) .................................................................................................... 8-57
 

Data)............................................................................................................................... 8-59
 

(Manufacturer Data)....................................................................................................... 8-61
 

(Test/Teardown Data) .................................................................................................... 8-63
 

(Manufacturer Data)....................................................................................................... 8-66
 

(Manufacturer Data)....................................................................................................... 8-67
 

(Manufacturer Data)....................................................................................................... 8-67
 

(Manufacturer Data)....................................................................................................... 8-67
 

LIST OF FIGURES
 

Figure 8.1 Flow Diagram of Inputs for the Determination of LCC and PBP................. 8-5
 

Figure 8.5 2.5W Regular AC/DC External Power Supplies: Base Case LCC Distribution 

Figure 8.6 18W Regular AC/DC External Power Supplies: Base Case LCC Distribution 

Figure 8.7 60W Regular AC/DC External Power Supplies: Base Case LCC Distribution 

Figure 8.8 120W Regular AC/DC External Power Supplies: Base Case LCC Distribution 

Figure 8.9 2.5W Regular AC/DC External Power Supplies: Distribution of Life-Cycle 

Figure 8.10 2.5W Regular AC/DC External Power Supplies: Distribution of PBPs 

Figure 8.2 Residential Sector Electricity Price Trend .................................................. 8-11
 

Figure 8.3 Commercial Sector Electricity Price Trend................................................. 8-12
 

Figure 8.4 Gasoline Prices for Years 2009 to 2035...................................................... 8-13
 

(Manufacturer Data)....................................................................................................... 8-26
 

(Manufacturer Data)....................................................................................................... 8-27
 

(Manufacturer Data)....................................................................................................... 8-27
 

(Manufacturer Data)....................................................................................................... 8-28
 

Cost Impacts (Manufacturer Data)................................................................................. 8-29
 

(Manufacturer Data)....................................................................................................... 8-29
 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

Figure 8.11 18W Regular AC/DC External Power Supplies: Distribution of Life-Cycle 

Cost Impacts (Manufacturer Data)................................................................................. 8-31
 

Figure 8.12 18W Regular AC/DC External Power Supplies: Distribution of PBPs 

Figure 8.13 60W Regular AC/DC External Power Supplies: Distribution of Life-Cycle 

Figure 8.14 60W Regular AC/DC External Power Supplies: Distribution of PBPs 

Figure 8.15 120W Regular AC/DC External Power Supplies: Distribution of Life-Cycle 

Figure 8.16 120W Regular AC/DC External Power Supplies: Distribution of PBPs 

Figure 8.17 Low Energy, Inductive Battery Charger: Base Case LCC Distribution 

Figure 8.18 Low Energy, Low Voltage Battery Charger: Base Case LCC Distribution 

Figure 8.19 Low Energy, High Voltage Battery Charger: Base Case LCC Distribution 

Figure 8.20 Medium Energy, Low Voltage Battery Charger: Base Case LCC Distribution 

Figure 8.21 High Energy Battery Charger: Base Case LCC Distribution (Manufacturer 

Figure 8.22 Low Energy, AC Out Battery Charger: Base Case LCC Distribution 

Figure 8.23 Low Energy, Low Voltage Battery Charger: Base Case LCC Distribution 

Figure 8.24 Low Energy, High Voltage Battery Charger: Base Case LCC Distribution 

Figure 8.25 Medium Energy, Low Voltage Battery Charger: Base Case LCC Distribution 

Figure 8.26 Low Energy, AC Out Battery Charger: Base Case LCC Distribution 

Figure 8.27 Low Energy, Inductive Battery Chargers: Distribution of Life-Cycle Cost
 

Figure 8.28 Low Energy, Inductive Battery Chargers: Distribution of PBPs 

Figure 8.29 Low Energy, Low Voltage Battery Chargers: Distribution of Life-Cycle Cost
 

Figure 8.30 Low Energy, Low Voltage Battery Chargers: Distribution of PBPs 

Figure 8.31 Low Energy, Low Voltage Battery Chargers: Distribution of Life-Cycle Cost
 

Figure 8.32 Low Energy, Low Voltage Battery Chargers: Distribution of PBPs 

Figure 8.33 Low Energy, High Voltage BC: Distribution of Life-Cycle Cost Impacts 

(Manufacturer Data)....................................................................................................... 8-31
 

Cost Impacts (Manufacturer Data)................................................................................. 8-33
 

(Manufacturer Data)....................................................................................................... 8-33
 

Cost Impacts (Manufacturer Data)................................................................................. 8-35
 

(Manufacturer Data)....................................................................................................... 8-35
 

(Manufacturer Data)....................................................................................................... 8-37
 

(Manufacturer Data)....................................................................................................... 8-38
 

(Manufacturer Data)....................................................................................................... 8-38
 

(Manufacturer Data)....................................................................................................... 8-39
 

Data)............................................................................................................................... 8-39
 

(Manufacturer Data)....................................................................................................... 8-40
 

(Test/Teardown Data) .................................................................................................... 8-41
 

(Test/Teardown Data) .................................................................................................... 8-41
 

(Test/Teardown Data) .................................................................................................... 8-42
 

(Test/Teardown Data) .................................................................................................... 8-42
 

Impacts (Manufacturer Data)......................................................................................... 8-43
 

(Manufacturer Data)....................................................................................................... 8-44
 

Impacts (Manufacturer Data)......................................................................................... 8-46
 

(Manufacturer Data)....................................................................................................... 8-46
 

Impacts (Test/Teardown Data) ...................................................................................... 8-48
 

(Test/Teardown Data) .................................................................................................... 8-48
 

(Manufacturer Data)....................................................................................................... 8-50
 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

Figure 8.34 Low Energy, High Voltage BC: Distribution of PBPs (Manufacturer Data) 8­

50
 

Figure 8.35 Low Energy, High Voltage BC: Distribution of Life-Cycle Cost Impacts 

(Test/Teardown Data) .................................................................................................... 8-52
 

Figure 8.36 Low Energy, High Voltage BC: Distribution of PBPs (Test/Teardown Data)
 

........................................................................................................................................ 8-52
 

Figure 8.37 Medium Energy, Low Voltage Battery Chargers: Distribution of Life-Cycle 

Cost Impacts (Manufacturer Data)................................................................................. 8-54
 

Figure 8.38 Medium Energy, Low Voltage Battery Chargers: Distribution of PBPs 

(Manufacturer Data)....................................................................................................... 8-54
 

Figure 8.39 Medium Energy, Low Voltage Battery Chargers: Distribution of Life-Cycle 

Cost Impacts (Test/Teardown Data) .............................................................................. 8-56
 

Figure 8.40 Medium Energy, Low Voltage Battery Chargers: Distribution of PBPs 

(Test/Teardown Data) .................................................................................................... 8-56
 

Figure 8.41 High Energy Battery Chargers: Distribution of Life-Cycle Cost Impacts 

(Manufacturer Data)....................................................................................................... 8-58
 

Figure 8.42 High Energy Battery Chargers: Distribution of PBPs (Manufacturer Data). 8­

58
 

Figure 8.43 Low Energy, AC Out Battery Chargers: Distribution of Life-Cycle Cost 

Impacts (Manufacturer Data)......................................................................................... 8-60
 

Figure 8.44 Low Energy, AC Out Battery Chargers: Distribution of PBPs (Manufacturer 

Data)............................................................................................................................... 8-60
 

Figure 8.45 Low Energy, AC Out Battery Chargers: Distribution of Life-Cycle Cost 

Impacts (Test/Teardown Data) ...................................................................................... 8-62
 

Figure 8.46 Low Energy, AC Out Battery Chargers: Distribution of PBPs 

(Test/Teardown Data) .................................................................................................... 8-62
 

Figure 8.47 Low Energy, Medium Voltage Battery Charger: Base Case LCC Distribution 

(Manufacturer Data)....................................................................................................... 8-64
 

Figure 8.48 Medium Energy, High Voltage Battery Charger: Base Case LCC
 

Distribution (Manufacturer Data) .................................................................................. 8-65
 

Figure 8.49 DC-DC, <9V Input Battery Charger: Base Case LCC Distribution 

(Manufacturer Data)....................................................................................................... 8-65
 

Figure 8.50 DC-DC, ≥9V Input Battery Charger: Base Case LCC Distribution 

(Manufacturer Data)....................................................................................................... 8-66
 

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CHAPTER 8. LIFE-CYCLE COST AND PAYBACK PERIOD ANALYSES 

8.1 INTRODUCTION 

This chapter describes the analysis the U.S. Department of Energy (DOE) conducts to 

evaluate the economic impacts on individual consumers of possible energy conservation 

standards for battery chargers (BC) and external power supplies (EPS). New standards usually 

decrease operating costs and increase purchase costs for consumers. This chapter describes the 

three metrics used in this analysis to determine the impact of standards on individual consumers: 

Life-cycle cost (LCC) is the total (discounted) consumer cost over the analysis period 

including purchase price, operating costs (including energy expenditures), and 

installation costs. 

Payback period (PBP) is the number of years it takes a customer to recover the generally 

higher purchase price of a more energy-efficient product through the operating cost 

savings of using the more energy-efficient product. The PBP is calculated as the change 

in first cost divided by the change in operating costs in the first year. 

Rebuttable payback period is a special case in which the PBP is calculated based on 

laboratory conditions, specifically DOE test procedure inputs. DOE calculates the 

aforementioned LCC and PBP using a range of inputs, which are designed to reflect 

actual conditions. 

Sections 8.2 and 8.3 discuss inputs to the LCC and PBP, respectively. Section 8.3.3 

presents the rebuttable presumption PBP and section 8.4 presents the results for the LCC and 

PBP. Key variables and calculations are presented for each metric. DOE performs the 

calculations discussed here using a series of Microsoft Excel® spreadsheets developed for this 

rulemaking. Stakeholders are invited to download and examine the spreadsheets, which are 

available at: 

http://www1.eere.energy.gov/buildings/appliance_standards/residential/battery_external.html. 

Appendix 8A presents details and instructions for using the spreadsheets. Appendix 8B 

presents sensitivity results and results using different input scenarios. Appendix 8C presents 

DOE’s application sampling methodology used in the LCC, and Appendix 8D presents further 

detail on the calculation of residential discount rates. 

8.1.1 General Approach for Life-Cycle Cost and Payback Period Analyses 

Recognizing that several inputs to the LCC and PBP analysis are either variable or 

uncertain, DOE incorporates Monte Carlo simulation and probability distributions into its LCC 

and PBP model. DOE incorporates both Monte Carlo simulation and probability distributions by 

using Microsoft Excel spreadsheets combined with Crystal Ball®, a commercially available addin program. 

8-1 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

The relationship between increasing selling price and increasing efficiency is the 

predominant influence on the LCC and PBP results. However, other factors related to the 

characteristics of the consumer using the products also affect the results. Based on the 

geographic region, sector, and application in which a consumer uses the BC or EPS, factors such 

as energy prices, sales tax, and energy usage can vary. By using the Monte Carlo simulation and 

separate sensitivity runs, DOE accounts for this variability. Since many BCs and EPSs are 

portable, it is possible for consumers to utilize the same product in both a residential and 

commercial setting. While DOE calculates an LCC for both the residential and commercial 

sectors, it does not attempt to quantify the extent to which residential consumers use their 

products in a commercial setting, or vice versa. 

For the LCC and PBP analyses, DOE considers variability in the discount rate. DOE also 

models variability in the electricity price by sector, base case efficiency distribution, product 

lifetime, sales tax rate, and energy consumption amount by representative unit. By developing 

samples, DOE can perform the LCC and PBP calculations and account for the variability in these 

inputs among a variety of consumer and regional data. DOE uses the Energy Information 

Administration’s (EIA) Form 861 from 2008 to develop regional electricity price samples. The 

LCC and PBP spreadsheets present the results of the analysis as average values, relative to the 

baseline conditions. 

The time period used for the LCC and PBP analyses in this rulemaking is the useful life 

of the application that the BC or EPS operates. This is because BCs and EPSs are often made 

specifically for use with particular consumer products, so their lifetimes relate directly to the 

lifetimes of those products. DOE assumes that once the consumer product has reached the end 

of its useful life, the user typically discards the associated BC or EPS. Therefore, for each 

representative unit, DOE has gathered lifetime values for consumer product applications. DOE 

then samples an application based on market-weighting for each representative unit and uses the 

mean lifetime associated with that application. In the event that an application lifetime and the 

associated EPS or BC lifetime do not coincide, DOE will use the EPS or BC lifetime in its 

analysis. 

DOE is conducting the LCC and PBP analyses on the baseline BCs and EPSs from the 

representative units and representative product classes (―representative units‖) identified in 

Chapter 3. Table 8.1.1 shows the set of 10 representative units that DOE is evaluating in this 

analysis. 

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Table 8.1.1 Representative Units and Product Classes Analyzed in the LCC and PBP 

Analyses 

Class A External Power Supply Representative Units 

2.5 Watt Regular AC/DC 

18 Watt Regular AC/DC 

60 Watt Regular AC/DC 

120 Watt Regular AC/DC 

Battery Charger Representative Product Classes 

Low Energy, Inductive 

Low Energy, Low Voltage 

Low Energy, High Voltage 

Medium Energy, Low Voltage 

High Energy 

Low Energy, AC Out 

DOE is also conducting the LCC and PBP analyses on the scaled BC product classes. 

DOE is considering the scaled BC product classes because these units represent a portion of the 

market that may not be captured by the representative units. The scaled EPS product classes, 

however, are not analyzed because the representative units chosen span the spectrum of possible 

output powers under consideration. More explanation is provided in chapter 5. Table 8.1.2 

shows the set of four scaled product classes that DOE is evaluating in this analysis. 

Table 8.1.2 Scaled Battery Charger Product Classes Analyzed in the LCC and PBP 

Analyses 

Battery Charger Scaled Product Classes 

Low Energy, Medium Voltage 

Medium Energy, High Voltage 

DC-DC, <9V Input 

DC-DC, ≥9V Input 

There are a number of end-use applications (―applications‖) that use EPSs and BCs from 

each representative unit and scaled BC product class outlined in Table 8.1.1 and Table 8.1.2, and 

oftentimes the applications are very different. This is because many of the same EPS or BC units 

can be used for a variety of applications. Since many of the inputs to the LCC model are 

dependent on the particular application, such as product lifetime, DOE considers an array of 

popular applications when evaluating each representative unit and scaled BC product class. 

Further detail on these applications and DOE’s methodology for selecting inputs can be found in 

appendix 8C of this preliminary analysis. 

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8.1.2 Overview of LCC and PBP Inputs 

As mentioned earlier, the LCC represents the total consumer expense over the analysis 

period, including purchase expenses, operating costs (including energy expenditures), and 

installation costs. DOE discounts future operating costs to the time of purchase and sums them 

over the analysis period. There is no ―residual value‖ for a BC or EPS, since it is often discarded 

along with the consumer product that it operates. The PBP represents the number of years it 

takes customers to recover the purchase price of more energy-efficient equipment through lower 

operating costs. The PBP is calculated as the change in first cost divided by the change in 

operating costs in the first year. 

DOE categorizes inputs to the LCC and PBP analysis as follows: (1) inputs for 

establishing the purchase expense, otherwise known as the total installed cost; and (2) inputs for 

calculating the expenses incurred during the operation of the BC or EPS, otherwise known as the 

operating cost. 

The primary inputs for establishing the life-cycle cost and payback period are: 

Manufacturer Selling Price (MSP): As discussed in Chapter 5, the MSP is the final price that 

manufacturers sell a product for, including the total cost to produce the product and any 

markups the manufacturer applies. The MSP does not account for any distribution or 

retail markups, taxes or installation. 

Markups: DOE then applies a series of markups to the MSP to convert it to a price that 

would be paid by the actual end-use consumer. 

Sales Tax: DOE then applies sales tax to convert the end user product price to a final product 

price including sales tax. Chapter 6 describes the sales tax markup in detail. 

Installation Cost: DOE considers installation costs to be zero for BCs and EPSs because 

installation would typically entail a consumer simply unpacking the BC or EPS from the 

box it was sold in and connecting the device to mains power and its associated product or 

battery. Because the cost of this ―installation‖ (which may be considered temporary, as 

intermittently used devices might be unplugged for storage) is not quantifiable in dollar 

terms, DOE considers the installation cost to be zero. 

Disposal Cost: DOE considers disposal cost to be zero for BCs and EPSs. 

The primary inputs for calculating the operating cost include the following: 

Unit Energy Consumption (in kWh/year): The annual site energy consumed by the BC or 

EPS at each efficiency level. See Chapter 7 for details of how DOE determines the unit 

energy consumption (UEC). 

Electricity Prices: DOE uses the average price per kilowatt-hour (i.e., $/kWh) paid by 

customers. DOE determines electricity prices using national average residential and 

commercial electricity prices for the sample calculation. For the Monte Carlo 

distribution, DOE uses average residential and commercial values for 13 regions and 

large states. DOE develops all electricity price inputs using 2008 EIA data. 

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Electricity Price Trends: DOE uses the EIA’s Annual Energy Outlook 2010 Early Release 

(AEO2010)i and projections from the Lieberman-Warner Climate Security Act of 2007ii 

to forecast electricity prices. For the results presented in this chapter, DOE uses the 

AEO2010 reference case to forecast future electricity prices. 

Start Year: The year in which the BC or EPS and its associated product are purchased. For 

the LCC and PBP analysis, DOE uses 2013 as the start year for all products. 

Lifetime: The total years in operation after which the consumer retires the BC or EPS from 

service, along with the product it operates. 

Discount Rate: The rate at which DOE discounts future expenditures to establish their value 

in the year of purchase (2013). 

Figure 8.1 depicts the relationships between the installed cost and the operating cost 

inputs for the calculation of the LCC and PBP. In this figure, the yellow boxes indicate the 

inputs, the green boxes indicate intermediate calculated values, and the blue boxes indicate the 

analysis outputs (the LCC and PBP). 

Manufacturer 

Selling Price

Markups

Final Product 

Price

Unit Energy 

Consumption

Electricity Prices

Annual 

Energy Cost

Lifetime

Discount 

Rate

Electricity 

Price Trend

Lifetime 

Operating 

Expense

Payback 

Period

Life-Cycle

Cost

Start Year

Sales Tax

Figure 8.1 Flow Diagram of Inputs for the Determination of LCC and PBP 

Table 8.1.3 summarizes the input values that DOE uses to calculate the LCC and PBP for 

BCs and EPSs. Each row summarizes the total installed cost inputs and operating costs, 

including the lifetime, discount rate, and electricity price trend. DOE characterizes several of the 

inputs with probability distributions that capture the input’s uncertainty and/or variability in the 

Monte Carlo analysis. Table 8.1.3 also lists the chapter of the Technical Support Document that 

details the inputs. 

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Table 8.1.3 Summary Information of Inputs for the Life-Cycle Cost and Payback Period 

Analyses 

Factor Weighted-Average Value TSD Reference 

Section 

Total Installed Cost Primary Inputs 

Manufacturer Selling Price Varies with BC and EPS Chapter 5 

Markups Varies with BC and EPS Chapter 6 

Sales Tax Varies by census region Chapter 6 

Operating Cost Primary Inputs 

Unit Energy Consumption Varies with BC and EPS by efficiency level Chapter 7 

Electricity Prices Vary by sector and census region Chapter 8 

Electricity Price Trends Vary with price forecast scenario Chapter 8 

Discount Rate Varies with sector Chapter 8 

Lifetime Varies with BC and EPS Chapter 3 

Sections 8.2 and 8.3 discuss the installed cost and operating cost inputs depicted in Table 

8.1.3. 

8.2 LIFE-CYCLE COST INPUTS 

8.2.1 Definition 

The LCC is the total customer cost over the life of a product, including total installed 

costs and operating costs. Future operating costs are discounted to the analysis start year (2013) 

and summed over the analysis period (the lifetime for each respective representative unit or 

scaled BC product class). The LCC is defined by the following equation: 

N

t

t

t

r

OC LCC IC

1

(1 )

Eq. 8.1 

where 

LCC = life-cycle cost ($),
 

IC = total installed cost ($), 

N = analysis period,
 

∑ = sum over the analysis period, from year 1 to year N,
 

OC = operating cost ($),
 

r = discount rate,
 

t = year for which operating cost is being determined,
 

DOE expresses all the costs in its LCC and PBP analyses in 2009 dollars. There are no 

replacement costs, disposal costs, or residual value associated with BCs or EPSs, so they are 

absent from the equation above. 

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IC FPP INST

 

 

 

 

 

 

 

 

 

 

 

8.2.2 Total Installed Cost Inputs 

The total installed cost to the customer is defined by the following equation: 

Eq. 8.2 

where 

IC = total installed cost, expressed in dollars, 

FPP = final product price (i.e., customer price for the product only, including 

sales tax), expressed in dollars, and 

INST = installation cost or the customer price to install products, expressed in 

dollars. This cost is assumed to be zero for all BCs and EPSs. 

In the product price determination (Chapter 6), DOE develops end user product prices 

and sales taxes to derive final product prices. Total installed costs are determined using: 

End user Product Price ($), and 

Sales Tax ($). 

The end user product price is the average purchase price a consumer pays before sales tax 

for BCs and EPSs. Since consumers often do not purchase BCs or EPSs individually, but rather 

as a component of the product they operate, the end user product price for a BC or EPS is 

derived as a component of the larger purchase price for the product it is purchased with. The 

markups applied to the final product are carried over for the BC or EPS component. The sales 

tax represents state and local sales taxes applied to the end user product price. It is a 

multiplicative factor that increases the end user product price. DOE calculates the total installed 

cost for the BCs and EPSs analyzed based on the following equation: 

PRICE MUTAX

IC FPP

Eq. 8.3 

where 

IC = total installed cost,
 

FPP = final product price, 

PRICE = end user product price, and
 

MUTAX = sales tax mark up
 

Chapter 6 provides detail on the end user product price and sales tax. 

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OC Econs EP EPT

 

 

 

 

 

 

 

 

 

 

 

8.2.3 Operating Cost Inputs 

The operating cost represents the costs incurred in the operation of the BC or EPS. Table 

8.2.1 lists the inputs for operating costs. The lifetime, discount rate, and compliance date of the 

standard are required to determine the operating cost and for establishing the operating cost 

present value. The electricity consumption for the baseline and other efficiency levels examined 

enable comparison of standards’ operating costs. 

Table 8.2.1 Inputs for Operating Costs 

Unit Energy Consumption 

Electricity Prices 

Electricity Price Trends 

Discount Rate 

Lifetime 

The UEC is the estimated energy that a BC or EPS consumes during normal use over the 

course of a year. Electricity prices used in the analysis are the price per kilowatt-hour in cents or 

dollars (e.g., $/kWh) paid by each customer for electricity. DOE uses electricity price trends to 

forecast electricity prices for future year analysis. These trends with the electricity price and 

annual UEC are used to calculate the energy cost in each year, which is the operating cost. DOE 

defines operating cost by the following equation: 

Eq. 8.4 

where 

OC = operating costs,
 

Econs = annual energy consumed,
 

EP = electricity price, and
 

EPT = electricity price trend factor relative to 2009.
 

Although operating costs for several other DOE rules have encompassed repair and 

maintenance costs, DOE does not consider these costs (which are usually associated with larger 

products and appliances) in the LCC for this rulemaking. In making this decision, DOE 

recognizes that the service life of a BC or EPS typically exceeds that of the consumer product 

with which it is designed to operate. Thus, a consumer would not incur repair or maintenance 

costs for a BC or EPS. Also, if a BC or EPS does fail, DOE expects that consumers would 

typically discard the EPS and purchase a replacement. 

The remainder of this section provides information about each of the above input 

variables that DOE used to calculate the operating costs for BCs and EPSs. 

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8.2.4 Unit Energy Consumption 

BCs and EPSs are unique appliances because they are always used in conjunction with 

other products of interest. Most BCs and EPSs are packaged with particular products; thus, 

consumers usually do not buy the BC or EPS directly. Instead, for example, consumers obtain 

an EPS for a video game system when buying the video game system itself. Thus, although the 

LCC and PBP analysis uses the consumer purchase prices of BCs and EPSs, in reality those 

prices are a ―hidden‖ portion of the prices that consumers pay for the products of interest. 

Because BCs and EPSs are used in conjunction with other products, their energy 

consumption is directly related to the usage of those other products as well as the technologies 

that the BC or EPS utilizes. The energy consumption of the analyzed BCs and EPSs is assessed 

in further detail in chapter 7, and the technologies of the analyzed BCs and EPSs are assessed in 

chapter 3 of the preliminary analysis. 

The energy use characterization (Chapter 7) details how DOE determines the UEC for 

baseline and standards-compliant products. The UEC varies with the product efficiency. That is, 

the energy consumption associated with standards-level products (i.e., products with efficiencies 

greater than baseline products) is less than the consumption associated with baseline products. 

As such, the UEC decreases with higher improved efficiency. An important input to determining 

the energy consumption is the total hours per year that the product is in operation in the different 

load states available to the product. With this information, the UEC can be calculated as a 

function of its efficiency. 

For the LCC and PBP analysis, DOE utilizes different UECs for each efficiency level of 

each representative unit and scaled BC product class. Since each representative unit and scaled 

BC product class encompasses multiple product applications, each with its own distinct usage 

profile and energy consumption levels, DOE uses a shipment-weighted average UEC for each 

representative unit and scaled BC product class analyzed in the LCC and PBP analysis for the 

sample calculation. For the Monte Carlo simulation analyses, DOE samples an application for 

each representative unit and scaled BC product class and uses the UECs associated with that 

application. Appendix 8C contains a complete listing of the application inputs associated with 

each representative unit and scaled BC product class, including the UECs associated with each 

efficiency level for the applications considered and the methodology for sampling these UECs. 

8.2.5 Electricity Prices 

DOE estimates electricity prices for residential and commercial consumers in each of the 

13 regions and large states by using EIA Form 861 data.iii Table 8.2.2 lists the 13 geographic 

regions and large states. The EIA Form 861 data are published annually and include annual 

electricity sales in kilowatt hours; revenues from electricity sales; and number of consumers for 

the residential and commercial sectors for every utility serving final consumers. The calculation 

of average electricity prices proceeds in two steps: 

1) For each utility, estimate an average residential and commercial price by dividing the 

residential or commercial revenues by residential or commercial sales. 

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2) Calculate a regional average price, weighting each utility with customers in a region 

by the number of residential or commercial consumers served in that region. 

The calculation uses the most recent available EIA data at the time the analysis was 

conducted, from 2008. Table 8.2.2 shows the results for each geographic region. Because DOE 

conducted the LCC and PBP analyses in 2009$, it needed to convert all electricity prices into 

2009$. To perform the necessary monetary conversion, DOE uses the consumer price index 

(CPI) to convert the electricity prices from 2008$ to 2009$. As described in the following 

section on electricity price trends, DOE normalizes energy prices to 2009. Therefore, to forecast 

energy prices for any given future year, DOE establishes energy prices for 2009. In Table 8.2.2, 

DOE uses data from the AEO2010 Early Release to estimate the electricity prices for 2009. 

DOE uses the CPI to adjust for inflation, and then multiplies the electricity price in 2008 by the 

ratio of the price in 2009 to that in 2008, as reported in the AEO2010 Early Release, so as to 

convert the electricity price to a 2009 estimate. 

Table 8.2.2 Electricity Prices by Census Division, 2009 

Census Division 

Electricity Prices,* 2009 

Residential Commercial 

2009$/kWh 2009$/kWh 

New England $0.170 $0.151 

Middle Atlantic $0.128 $0.108 

East North Central $0.102 $0.088 

West North Central $0.086 $0.071 

South Atlantic $0.099 $0.084 

East South Central $0.090 $0.088 

West South Central $0.093 $0.084 

Mountain $0.096 $0.082 

Pacific $0.102 $0.095 

New York State $0.186 $0.166 

California $0.134 $0.120 

Texas $0.127 $0.119 

Florida $0.113 $0.097 

U.S. Weighted Average $0.115 $0.101 

* DOE converts dollars to 2009$ by multiplying costs in 2008$ by the ratio of 2009 CPI (214.5) to 2008 CPI 

(215.3). DOE converts the price for 2008 to the price in 2009 by multiplying the 2008 price by the ratio of the 

average AEO electricity price in 2009 to the average AEO electricity price in 2008. 

8.2.6 Electricity Price Trend 

The electricity price trend projects the future cost of electricity to 2035. DOE calculates 

the LCC and PBP using three separate projections from AEO2010: reference, low economic 

growth, and high economic growth. The AEO2010 Early Release was the most recent AEO 

available at the time of this preliminary analysis. This AEO2010 contained only the referencecase economic growth projection, however. In order to develop high-economic-growth and loweconomic-growth cases for the LCC and PBP analysis, DOE obtained the differences between 

the reference case and the high- and low-economic-growth cases in the March 2009 AEO2009,

iv 

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which includes all three cases. DOE then utilized these differences as scaling factors to generate 

high- and low-economic-growth cases based on the AEO2010 Early Release reference case. 

DOE also considers an electricity price projection using a carbon cap and trade scenario 

based upon the Lieberman-Warner Climate Security Act of 2007. This scenario illustrates an 

elevated electricity price projection based on emissions regulations as outlined in the EIA’s 

S.2191 report accompanying the Act. 

These four cases reflect the uncertainty of economic growth in the forecast period. The 

high and low growth cases show the projected effects of alternative growth assumptions on 

energy markets, while the carbon cap and trade scenario illustrates the possible effects of 

emissions regulations. DOE normalizes these four scenarios to the 2009 electricity price, and 

then uses that electricity price factor to scale the 2009 electricity prices. Figure 8.2 and Figure 

8.3 show the residential and commercial electricity price trends, respectively, based on the three 

AEO2010 Early Release projections and the carbon cap and trade scenario projection. The LCC 

results presented in this chapter are based on the AEO2010 Early Release reference case. 

0.80

0.85

0.90

0.95

1.00

1.05

1.10

1.15

2005 2010 2015 2020 2025 2030 2035 2040

Price Trend (2009=1)

Year

Reference

High Growth

Low Growth

Carbon Cap

Start Year: 2013

Figure 8.2 Residential Sector Electricity Price Trend 

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0.70

0.75

0.80

0.85

0.90

0.95

1.00

1.05

1.10

1.15

2005 2010 2015 2020 2025 2030 2035 2040

Price Trend (2009=1)

Year

Reference

High Growth

Low Growth

Carbon Cap

Start Year: 2013

Figure 8.3 Commercial Sector Electricity Price Trend 

In the LCC spreadsheet, these electricity price trends are used to project electricity prices 

into the future, which are then multiplied by the annual energy usage. The resulting operating 

costs are presented in both the LCC spreadsheets and the LCC results tables in this chapter. 

8.2.7 Gasoline Prices and Trends 

For BCs powered by automotive power sources (scaled BC product class 9), DOE 

calculated consumer energy cost savings using gasoline prices rather than electricity prices. 

DOE obtained yearly gasoline prices and projections from the AEO2010 Early Release, which 

expressed prices per gallon of gasoline. DOE converted these prices into dollars per kilowatthour to project the total gasoline cost for each UEC. 

DOE converted the gasoline prices to dollars per kilowatt-hour by using an energy 

equivalence conversion factor and an automobile energy conversion efficiency estimate. An 

estimate of 33.705 kWh/gallon of gasoline was used to estimate fully-efficient conversion of 

energy. v From this estimate, DOE applied an average automobile energy conversion efficiency 

of 21-percent, which represents the typical efficiency in converting gasoline to electric power.vi 

Using these figures, DOE estimates 7.08kWh/gallon when powering a BC through an automotive 

power source. DOE then converted the AEO2010 Early Release gasoline price estimates 

(expressed as dollars per gallon) into dollars per kilowatt-hour. The resulting gasoline prices per 

kilowatt-hour are expressed in Figure 8.4. 

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$0.30

$0.35

$0.40

$0.45

$0.50

$0.55

$0.60

2005 2010 2015 2020 2025 2030 2035 2040

Gas Price (2009$/kWh)

Year

Start Year: 2013

Figure 8.4 Gasoline Prices for Years 2009 to 2035 

8.2.8 Lifetime 

DOE considers the lifetime of a BC or EPS to be from the moment it is purchased for enduse up until the time when it is permanently retired from service. Because the typical BC or EPS 

is purchased for use with a single associated application, DOE assumes that it will remain in 

service for as long as the application does. Since there are multiple applications with different 

lifetimes for a single representative unit or scaled BC product class, a shipment-weighted 

average lifetime is calculated from the relevant applications for that representative unit or scaled 

BC product class in the Sample Calculation. The Monte Carlo simulation analysis samples a 

lifetime from the relevant applications for each representative unit or scaled BC product class. 

Since each application has its own lifetime estimate, this provides a distribution of lifetime 

estimates for a given representative unit or scaled BC product class. Further detail on this 

application sampling methodology can be found in Appendix 8C to this preliminary analysis. 

Chapter 3 of this TSD contains the lifetimes for the selected applications and the methodology 

for deriving these estimates. 

Even though many of the technology options to improve BC and EPS efficiencies may 

result in an increased useful life for the BC or EPS, the lifetime of the BC or EPS is still directly 

tied to the lifetime of its associated application. Even if an EPS or BC has a lifetime that exceeds 

the lifetime of its application, the typical consumer will not use the EPS or BC once the 

application has been discarded. For this reason, the baseline and standard level designs for the 

LCC and PBP analyses all use the same lifetime estimate. Further detail on product lifetimes 

and how they relate to applications can be found in chapter 3 of this TSD. 

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8.2.9 Discount Rate 

The discount rate is the rate at which DOE discounts future expenditures to establish their 

present values. In the LCC analysis, DOE derives the discount rates separately for residential 

and commercial consumers. For residential consumers, DOE estimates the discount rate by 

looking across all possible debt or asset classes that might be used to purchase BCs or EPSs. For 

the commercial consumers, DOE estimates the cost of capital for commercial companies by 

examining both debt and equity capital, and develops an appropriately weighted average of the 

cost to the company of equity and debt financing. 

8.2.9.1 Residential Discount Rate 

DOE’s approach for the residential discount rate involves identifying all possible debt or 

asset classes that might be used to purchase BCs or EPSs, including household assets that might 

be affected indirectly.1 DOE does not include debt from primary mortgages and equity of assets 

considered non-liquid (such as retirement accounts), since these would likely not be used to 

finance BC or EPS purchases. DOE estimates the average shares of the various debt and equity 

classes in the average U.S. household equity and debt portfolios using the Federal Reserve’s 

Survey of Consumer Finances (SCF) data for 1989, 1992, 1995, 1998, 2001, 2004, and 2007.vii 

Table 8.2.3 shows the average shares of each considered class. DOE uses the mean share of each 

class across the seven survey years (18 years) as the basis for estimating household financing of 

BCs and EPSs. 

An indirect effect would arise if a household sold assets to pay off a loan or credit card debt that might have been 

used to finance the actual EPS or BC purchase. 

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Table 8.2.3 Average Percentage Shares of Household Debt and Equity Types 

Type 

1989 SCF 

% 

1992 SCF 

% 

1995 SCF 

% 

1998 SCF 

% 

2001 SCF 

% 

2004 SCF 

% 

2007 SCF 

% 

Mean 

% 

Home Equity Loans 2.2 1.9 0.9 1.0 1.2 2.9 2.5 1.8 

Credit Cards 0.0 2.2 2.6 2.2 1.7 2.0 2.5 1.9 

Other Installment Loans 3.1 1.8 1.4 1.7 1.1 1.4 1.2 1.7 

Other Residential Loans 0.0 7.0 5.3 4.4 3.1 5.9 7.3 4.7 

Other Line of Credit 1.2 0.6 0.4 0.0 0.3 0.5 0.3 0.5 

Checking Accounts 6.3 4.8 4.9 4.0 3.7 4.3 3.5 4.5 

Savings and Money Market 20.9 19.3 14.3 13.1 14.5 15.4 13.3 15.8 

Certificate of Deposit (CD) 15.8 12.0 9.5 7.1 5.5 6.0 6.6 8.9 

Savings Bond 2.4 1.7 2.2 1.1 1.2 0.9 0.7 1.5 

Bonds 15.0 12.6 10.7 7.1 8.0 8.6 6.8 9.8 

Stocks 24.4 24.7 26.4 37.7 38.1 28.4 29.3 29.8 

Mutual Funds 8.7 11.4 21.3 20.5 21.6 23.7 26.0 19.1 

Total 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 

DOE estimates interest or return rates associated with each type of equity and debt. The 

data source for the interest rates for loans, credit cards, and lines of credit is the Federal Reserve 

Board’s SCF in 1989, 1992, 1995, 1998, 2001, 2004, and 2007. The top half of Table 8.2.4 

shows the average nominal interest rates in each year and the inflation rates used to calculate real 

rates (using the Fisher formula).2 For home equity loans, DOE calculates effective interest rates 

using a tax adjustment since interest on such loans is tax deductible. The bottom half of the table 

shows the average effective real interest rates in each year and the mean rate across all the years. 

Since the interest rates for each debt carried by households in these years were established over 

18 years, DOE believes they are representative of rates that may be in effect in 2013. 

2 Fisher formula is given by: Real Interest Rate = [(1 + Nominal Interest Rate) / (1 + Inflation Rate)] – 1. 

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Table 8.2.4 Average Nominal and Real Interest Rates for Household Debt Classes 

Type 1989 SCF 1992 SCF 1995 SCF 1998 SCF 2001 SCF 2004 SCF 2007 SCF Mean 

Nominal Interest Rates % 

Home Equity Loans 8.4 6.4 7.0 6.8 6.0 3.6 5.8 6.3 

Credit Cards* - - 14.1 14.0 13.9 11.1 12.4 13.1 

Other Installment Loans 8.4 7.5 8.5 7.6 8.3 8.1 8.8 8.2 

Other Residential Loans 9.8 8.9 8.3 8.0 7.7 6.0 6.4 7.9 

Other Line of Credit 14.4 12.5 11.6 11.6 9.4 7.6 9.6 11.0 

Inflation rate 4.82 3.01 2.83 1.56 2.85 2.66 2.85 

Real Interest Rates % 

Home Equity Loans 4.5 4.1 4.8 5.4 3.7 1.5 3.5 3.9 

Credit Cards* - - 11.0 12.1 10.9 8.4 9.6 10.4 

Other Installment Loans 4.6 5.7 6.5 6.4 6.3 6.1 6.8 6.1 

Other Residential Loans 4.6 5.6 5.3 6.1 4.7 3.2 3.4 4.7 

Other Line of Credit 9.3 9.3 8.4 9.7 6.2 4.9 6.7 7.8 

*No interest rate data available for credit cards in 1989 or 1992. 

To account for variation among new households, DOE samples a rate for each household 

from a distribution of rates for each of the above debt classes. DOE develops a probability 

distribution of interest rates for each debt class based on the SCF data. Appendix 8D presents 

the probability distribution of interest rates for each debt class that DOE used in the LCC and 

PBP analyses. 

Similar rate data are not available from the SCF for the asset classes, so DOE derives 

data for these classes from national historical data. The interest rates associated with certificates 

viii ix of deposit (CDs), savings bonds, and bonds (AAA corporate bonds) x are from Federal 

Reserve Board time-series data 1979-2009. DOE assumes rates on checking accounts to be zero. 

Rates on savings and money market accounts are from Cost of Savings Index data covering 

1984-2009.xi The rates for stocks are the annual returns on the Standard and Poor’s (S&P) 500 

1979-2009.xii The mutual fund rates are a weighted average of the stock rates (two-thirds 

weight) and the bond rates (one-third weight) in each year from 1979 to 2009. DOE adjusts the 

nominal rates to real rates using the annual inflation rate in each year. Average nominal and real 

interest rates for the classes of assets are shown in Table 8.2.5. Since the interest and return rates 

for each asset type cover a range of time, DOE believes they are representative of rates that may 

be in effect in 2013. 

8-16 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

 

 

Table 8.2.5 Average Nominal and Real Interest Rates for Household Equity Types 

Type Average Nominal Rate % Average Real Rate % 

Checking Accounts -­ -­

Savings and Money Market 5.3 2.3 

CDs 6.4 2.4 

Savings Bonds 8.3 4.2 

Bonds 8.4 4.3 

Stocks 12.8 8.6 

Mutual Funds 11.3 7.1 

To account for variation among new households, DOE samples a rate for each household 

from a distribution of rates for each of the above asset types. DOE develops a normal probability 

distribution of interest rates for each asset type by using the mean value and standard deviation 

from the distribution. Appendix 8D presents the probability distribution of interest rates for each 

asset type that DOE used in the LCC and PBP analysis. 

Table 8.2.6 summarizes the mean real effective rates of each type of equity or debt. DOE 

determines the average share of each debt and asset using SCF data for 1989, 1992, 1995, 1998, 

2001, 2004, and 2007. Each year of SCF data provides the debt and asset shares for U.S. 

households. DOE averages the debt and asset shares over the seven years of survey data to 

arrive at the shares shown below. The average rate across all types of household debt and equity, 

weighted by the shares of each class, is 5.6-percent. 

Table 8.2.6 Shares and Interest or Return Rates Used for Household Debt and Equity 

Types 

Type 

Average Share of Household 

Debt Plus Equity* 

% 

Mean Effective Real Rate** 

% 

Home Equity Loans 1.8 3.9 

Credit Cards 1.9 10.4 

Other Installment Loans 1.7 6.1 

Other Residential Loans 4.7 4.7 

Other Line of Credit 0.5 7.8 

Checking Accounts 4.5 0.0 

Savings and Money Market Accounts 15.8 2.3 

CDs 8.9 2.4 

Savings Bonds 1.5 4.2 

Bonds 9.8 4.3 

Stocks 29.8 8.6 

Mutual Funds 19.1 7.1 

Total/Weighted-Average Discount Rate 100.0 5.6 

* Not including primary mortgage or retirement accounts.
 

** Adjusted for inflation and, for home equity loans, loan interest tax deduction.
 

8-17 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

ke Rf ERP

 

 

 

 

 

8.2.9.2 Commercial Discount Rate 

Most companies use both debt and equity capital to fund investments; for most 

companies, therefore, the cost of capital is the weighted average of the cost to the firm of equity 

and debt financing.xiii 

DOE estimates the cost of equity financing using the Capital Asset Pricing Model 

(CAPM). The CAPM, among the most widely used models to estimate the cost of equity 

financing, assumes that the cost of equity is proportional to the amount of systematic risk 

associated with a firm. For example, the cost of equity financing tends to be high when a firm 

faces a large degree of systematic risk, and the cost tends to be low when the firm faces a small 

degree of systematic risk. 

The degree of systematic risk facing a firm and the subsequent cost of equity financing 

are determined by several variables, including the risk coefficient of a firm (beta, or B), the 

expected return on risk-free assets (Rf), and the additional return expected on assets facing 

average market risk (known as the equity risk premium, or ERP). The beta indicates the degree 

of risk associated with a given firm, relative to the level of risk (or price variability) in the 

overall stock market. Betas usually vary between 0.5 and 2.0. A firm with a beta of 0.5 faces 

half the risk of other stocks in the market; a firm with a beta of 2.0 faces twice the overall stock 

market risk. 

Following this approach, the cost of equity financing for a particular company is by the 

equation: 

Eq. 8.5 

where 

ke = the cost of equity for a company, expressed in dollars,
 

Rf = the expected return of the risk-free asset, expressed in dollars,
 

β = the risk coefficient, and
 

ERP = the expected equity risk premium, expressed in dollars.
 

The cost of debt financing (kd) is the yield or interest rate paid on money borrowed by a 

company (raised, for example, by selling bonds). As defined here, the cost of debt includes 

compensation for default risk and excludes deductions for taxes. 

DOE estimates the cost of debt for companies by adding a risk adjustment factor to the 

current yield on long-term corporate bonds (the risk-free rate). This procedure is used to 

estimate current and future company costs to obtain debt financing. The adjustment factor is 

based on indicators of company risk, such as credit rating or variability of stock returns. 

8-18 

EERE-2008-BT-STD-0005 COMMENT 31
k ke we kd wd

 

 

 

 

 

 

 

 

 

 

 

The discount rate of companies is the weighted average cost of debt and equity financing, 

less expected inflation. DOE estimates the discount rate using the equation: 

Eq. 8.6 

where 

k = the (nominal) cost of capital, 

ke and kd = the expected rates of return on equity and debt, 

respectively, and 

we and wd = the proportion of equity and debt financing, respectively. 

The real discount rate deducts expected inflation from the nominal rate. 

The expected return on risk-free assets, or the risk-free rate, is defined by the current 

yield on long-term (20-year) Government bonds, as suggested by Ibbotson’s Associatesxiv and 

Damodaran.xii The ERP represents the difference between the expected (average) stock market 

return and the risk-free rate. As Table 8.2.7 shows, DOE uses an ERP estimate of 5.5-percent, 

which it took from the Damodaran Online site (a private website associated with New York 

University’s Stern School of Business, which aggregates information on corporate finance, 

investment, and valuation).xv 

DOE calculates an expected inflation of 1.6-percent from the average of the projected 

change in gross domestic product (GDP) prices in the Economic Report of the President.xvi DOE 

obtained the cost of debt, percent debt financing, and systematic firm risk from the Damodaran 

Online website. Table 8.2.7 shows average values across all private companies. However, the 

cost of debt, percent debt financing, and systematic firm risk vary by sector. 

Table 8.2.7 Variables Used to Estimate Company Discount Rates 

Variable Symbol Average 

Value 

% 

Source 

Risk-Free Asset Return Rf 5.3 Damodaran Online 

Equity Risk Premium ERP 5.5 Damodaran Online 

Expected Inflation R 1.6 2010 Economic Report of the President 

Cost of Debt (After Tax) kd 6.0 Damodaran Online 

Percent Debt Financing wd 27.9 Damodaran Online 

Systematic Firm Risk B 1.0 Damodaran Online 

In the commercial building sector, BCs and EPSs are purchased and owned by 

commercial companies, industrial companies and the Government. DOE uses a sample of 4,774 

companies drawn from these owner categories to represent BC and EPS purchasers. It took the 

sample from the list of companies included in the Value Line investment surveyxvii and listed on 

the Damodaran Online website. DOE obtained the cost of debt, the firm beta, the percent of debt 

and equity financing, the risk-free return, and the equity risk premium from Damodaran Online. 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

 

 

DOE estimates the cost of debt financing for these companies from the long-term 

Government bond rate and the standard deviation of the stock price. For Government-officetype owners, the discount rate represents an average of the Federal rate and the State and local 

bond rate. DOE drew the Federal rate directly from the U.S. Office of Management and Budget 

xviii discount rate for investments in Government building energy efficiency. DOE estimates the 

State and local discount rate from the interest rate on State and local bonds between 1979 and 

2009.ix DOE uses this information to estimate the weighted-average cost of capital for the 

sample of companies included in the company database. 

The cost of capital may be viewed as the discount rate that should be used to reduce the 

future value of typical company project cash flows. It is a nominal discount rate, since 

anticipated future inflation is included in both stock and bond expected returns. Deducting 

expected inflation from the cost of capital provides estimates of the real discount rate by 

ownership category (see Table 8.2.8). The mean real discount rate for these companies varies 

between 3.1-percent (Government offices) and 8.0-percent (industrial companies). 

Table 8.2.8 Real Discount Rates by BC and EPS Ownership Category 

Ownership Category SIC 

Codes* 

Mean Real 

Discount Rate 

% 

Standard 

Deviation 

% 

Number of 

Observations 

Industrial Companies 1 – 4 8.0 1.9 2,726 

Commercial Trade 5 7.7 1.8 280 

Commercial Finance, Insurance & Real Estate 6 6.6 1.7 852 

Commercial Services 7 – 8 7.6 1.7 916 

Government Offices N/A 3.1 1.2 N/A 

* SIC Codes refer to the U.S. Standard Industrial Classification system.
 

Source: Navigant Consulting, Inc. calculations based on firms sampled from the Damodaran Online website.
 

DOE’s approach for estimating the cost of capital provides a measure of the discount rate 

spread as well as the average discount rate. DOE infers the discount rate spread by ownership 

category from the standard deviation, which ranges between 1.2-percent and 1.9-percent (Table 

8.2.8). 

To estimate the share of each ownership category in total commercial sector purchases of 

BCs and EPSs, DOE uses the share of each category in total paid employees. DOE uses the most 

current data reported by the U.S. Census Bureau to see the number of employees by industry, xix 

for the Federal government, xx and for State and Local governments.xxi DOE uses the number of 

employees as a proxy for the share of each ownership category because the prevalence of most 

BCs and EPSs will vary depending on the number of individual users for a given device. Table 

8.2.9 presents the estimated shares of commercial BC and EPS purchases by ownership category. 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 8.2.9 Estimated Share of BC and EPS Purchases by Ownership Category in 

Commercial Sector 

Ownership Category Percent (%) 

Industrial Companies 23.3 

Commercial Trade 12.8 

Commercial Finance, Insurance & Real Estate 6.4 

Commercial Services 43.6 

Government Offices 13.9 

Source: U.S. Census Bureau. 

DOE estimates discount rate distributions for the different sectors as a weighted average 

of the distributions for the different ownership types. Table 8.2.10 summarizes the weighted 

average real discount rates in the residential and commercial sectors. 

Table 8.2.10 Average Real Discount Rate by Sector 

Sector Discount Rate 

% 

Residential 5.6 

Commercial 7.0 

8.2.10 Product Energy Efficiency in the Base Case 

For purposes of conducting the LCC analysis, DOE analyzed candidate standard levels 

relative to a base case (i.e., a case without new energy conservation standards). This requires an 

estimate of the distribution of product efficiencies in the base case (i.e., what consumers would 

have purchased in 2013 in the absence of new standards). Rather than analyzing the impacts of a 

particular standard level assuming that all consumers will purchase products at the baseline 

efficiency level, DOE conducted the analysis by taking into account the breadth of product 

energy efficiencies that consumers are expected to purchase under the base case. 

As discussed in section 8.1.1, DOE’s approach for conducting the LCC analysis for BCs 

and EPSs relied on developing samples of consumers that use each of the products, and using a 

Monte Carlo simulation technique to perform the LCC calculations on the consumers in the 

sample. DOE assigned each consumer in the sample a unique product energy efficiency taken 

from the estimated base case distribution of product energy efficiencies in the compliance year. 

The energy efficiency distributions used for each application and each representative unit or 

scaled BC product class are presented in chapter 3 of the TSD. The applications assigned to each 

representative unit and scaled BC product class, and their respective energy efficiency 

distribution, is explained in further detail in Appendix 8C. 

DOE calculated the efficiency distributions by evaluating tested efficiency data for each 

representative unit and scaled BC product class. The tested efficiencies were then binned into 

the appropriate standards-level and weighted by the shipments of the application tested. DOE 

assumed that the current averages for BCs are reasonable to use as a base case for 2013, but 

assumed a modest improvement in EPS efficiency from 2009 to 2013. This is because Europe 

8-21 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

recently passed efficiency standards requiring EPSs to meet the EISA level (CSL 0), and the 

efficiency requirement is set to rise to Energy Star 2.0 (CSL 1) by April 2011. DOE assumes 

this will impact the American market by shifting EPS efficiencies higher by year 2013. Further 

detail on this analysis can be found in chapter 9 of the TSD. Table 8.2.11 and Table 8.2.12 show 

the application-weighted efficiency distributions that were used for each representative unit. 

Table 8.2.13 shows the application-weighted efficiency distributions that were used for each 

scaled BC product class. 

Table 8.2.11 Base Case Energy Efficiency Market Shares for Class A External Power 

Supplies in 2013 

Energy Market Share (%) 

Efficiency Level 2.5 Watt 18 Watt 60 Watt 120 Watt 

Baseline 34.0 34.0 34.0 34.0 

1 50.7 50.7 50.7 50.7 

2 12.0 12.0 12.0 12.0 

3 3.3 3.3 3.3 3.3 

4 0.0 0.0 0.0 0.0 

Table 8.2.12 Base Case Energy Efficiency Market Shares for Battery Chargers in 2013 

Energy 

Efficiency Level 

Market Share (%) 

Low E, 

Inductive 

Low E, 

Low V 

Low E, 

High V 

Medium E, 

Low V High E Low E, AC Out 

Baseline 75.0 39.2 18.7 43.4 50.0 66.7 

1 12.5 58.0 43.0 16.3 20.0 22.2 

2 12.5 2.8 38.3 40.3 30.0 11.1 

3 0.0 0.0 0.0 0.0 0.0 0.0 

Table 8.2.13 Base Case Energy Efficiency Market Shares for Scaled Battery Charger 

Product Classes in 2013 

Energy 

Efficiency Level 

Market Share (%) 

Low E, 

Medium V 

Medium E, 

High V 

DC-DC, 

<9V Input 

DC-DC, 

≥9V Input 

Baseline 34.0 50.0 39.2 39.2 

1 54.0 20.0 58.0 58.0 

2 12.0 30.0 2.8 2.8 

3 0.0 0.0 0.0 0.0 

8.2.11 Compliance Date of Standard 

The compliance date is the date when a new standard becomes operative, i.e., the date by 

which BC and EPS manufacturers must manufacture products that comply with the standard. 

DOE’s publication of a final rule in this standards rulemaking is scheduled for completion in 

July 2011. The compliance date for amended EPS standards is July 1, 2013. (42 U.S.C. 

6295(u)(3)(D)(i)(II)(bb) The compliance date for BC standards is also targeted to be July 1, 

2013. DOE calculates the LCCs for all consumers as if each would purchase a new product in 

the year the standard takes effect (2013). However, DOE bases the cost of the equipment on the 

most recent available data; all dollar values are expressed in 2009$. 

8-22 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

 

 

8.3 PAYBACK PERIOD INPUTS 

8.3.1 Definition 

The PBP is the amount of time it takes the consumer to recover the assumed higher 

purchase cost of a more energy-efficient product as a result of lower operating costs. 

Numerically, the PBP is the ratio of the increase in purchase cost (i.e., from a less efficient 

design to a more efficient design) to the decrease in annual operating expenditures. This type of 

calculation is known as a ―simple‖ PBP, because it does not take into account changes in 

operating cost over time or the time value of money. That is, the calculation is done at an 

effective discount rate of zero percent. 

The equation for PBP is: 

OC

IC PBP

Eq. 8.7 

where 

PBP = payback period in years, 

∆IC = difference in the total installed cost between the more efficient 

standard level product (efficiency levels 1, 2, etc.) and the baseline 

(efficiency level 0) product, and 

∆OC = difference in annual operating costs. 

PBPs are expressed in years. PBPs greater than the life of the product mean that the 

increased total installed cost of the more efficient product is not recovered in reduced operating 

costs over the lifetime of that product. Because all BC and EPS designs in the LCC and PBP 

analyses save energy and thus yield a positive ∆OC, PBPs that are negative or equal to zero 

indicate that the total installed cost of the equipment that meets the higher EL is less than that of 

the baseline. 

8.3.2 Inputs 

The data inputs to the PBP calculation are the total installed cost of the product to the 

customer for each candidate standard level (CSL) and the annual (first year) operating costs for 

each CSL. The only input to the total installed cost is the final product price since the 

installation cost is assumed to be zero for BCs and EPSs. The inputs to the operating costs are 

the BC’s or EPS’s UEC and the cost of electricity. The PBP calculation uses the same inputs as 

the LCC calculation described in section 8.2, except that electricity price trends are not required. 

Since the PBP is a ―simple‖ (undiscounted) PBP, the required electricity cost is only for the year 

in which a new energy conservation standard is to take effect—in this case, 2013. The electricity 

price DOE uses in the PBP calculation is the price projected for 2013, expressed in 2009$, but 

not discounted to 2009. DOE does not use discount rates in the PBP calculation. 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

8.3.3 Rebuttable Presumption Payback Period 

Section 325(o)(2)(B)(iii) of EPCA establishes a rebuttable presumption that a standard 

for BCs or EPSs is economically justified if the Secretary finds that ―the additional cost to the 

consumer of purchasing a product complying with an energy conservation standard level will be 

less than three times the value of the energy. . . savings during the first year that the consumer 

will receive as a result of the standard, as calculated under the applicable test procedure . . . .‖ 

(42 U.S.C. 6295(o)(2)(B)(iii)) This rebuttable presumption test is an alternative path to 

establishing economic justification, as compared to consideration of the seven factors set forth in 

42 U.S.C. 6295(o)(2)(B)(i)(I)-(VII). 

For EPSs and BCs, energy savings calculations in the LCC and PBP analyses use both 

the relevant test procedures as well as the relevant usage profiles. Because DOE calculates 

payback periods in a methodology consistent with the rebuttable presumption test for EPSs and 

BCs in the LCC and payback period analyses, DOE is not performing a stand-alone rebuttable 

presumption analysis, as it is already embodied in the LCC and PBP analyses. 

8.4 LIFE-CYCLE COST AND PAYBACK PERIOD RESULTS 

This section presents LCC results for each BC and EPS representative unit and scaled BC 

product class that DOE considers. This section uses the terms ―positive LCC savings‖ and 

―negative LCC savings.‖ When a standard results in ―positive LCC savings,‖ the life cycle cost 

of the standards-compliant BC or EPS is less than the life-cycle cost of the baseline BC or EPS 

and the consumer will benefit. A consumer is adversely affected when a standard results in 

―negative LCC savings‖ (i.e., when the life-cycle cost of the standards-compliant BC or EPS is 

higher than the life-cycle cost of the baseline BC or EPS). As mentioned previously, DOE 

characterized the uncertainty and variability of many of the inputs to the analysis with 

probability distributions and then used a Monte Carlo simulation technique to perform the LCC 

and PBP calculations. DOE calculated the average LCC and LCC savings and the median and 

average PBP for each of the CSLs. 

DOE calculated LCC savings and PBPs at each efficiency level relative to the base case 

products that it assigned to the consumers. For some consumers, DOE assigned base case 

products that are more energy efficient than some of the standard levels. If a consumer was 

assigned a product energy efficiency that is greater than or equal to the energy efficiency of the 

standard level under consideration, the LCC calculation reveals that this consumer is not 

impacted by an increase in product energy efficiency to the standard level, and will experience 

LCC savings of $0. For that reason, the average LCC impacts are not equal to the difference 

between the LCC of a specific standard level and the LCC of the baseline products. The PBP 

calculations, however, only consider users who would be affected by the standard. 

This section presents LCC and PBP results for the residential sector using the energy 

price forecast in the Reference case from the AEO2010 Early Release. Appendix 8B presents 

results for the commercial sector, results using the energy price forecasts in the Low, High, and 

Carbon Cap and Trade growth cases, and results for high-savings and low-savings input 

scenarios. 

8-24 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

In the subsections below, DOE presents figures showing the distribution of LCCs in the 

base case for each representative unit and scaled BC product class. Also presented below are 

figures showing the distribution of LCC impacts and the distribution of PBPs. The distributions 

of LCCs are presented as frequency charts that show the distribution of LCCs with their 

corresponding probability of occurrence. DOE used box-and-whisker plots to show the LCC 

savings and PBP impacts at each standard level considered. DOE generated the figures for the 

distributions from a Monte Carlo simulation run based on 1,000 samples. 

8.4.1 Non-Class A External Power Supply Results 

As indicated in chapter 5, DOE did not generate engineering analysis outputs for NonClass A EPSs in the preliminary analysis. The engineering analysis will consider Non-Class A 

EPSs in the NOPR phase. At that time, DOE will examine the LCC and PBP of these products. 

Please refer to the Determination Concerning the Potential for Energy Conservation Standards 

for Non-Class A External Power Supplies published on November 3, 2009 (74 FR 56928) for the 

most current LCC and PBP analysis for these products. 

8.4.2 Class A External Power Supply Results 

DOE conducted a life-cycle cost analysis on four representative units for Class A EPSs at 

different levels of output power: 2.5 watts, 18 watts, 60 watts, and 120 watts. As discussed in 

chapter 5, DOE created two sets of cost-efficiency curves for each of the four representative 

units using data from manufacturer interviews and data from DOE’s own efficiency tests and 

cost teardowns (tests/teardowns). For the data from manufacturer interviews, DOE aggregated 

the results from various manufacturers. As a result, DOE had to normalize the MSP values 

across manufacturers. For this reason, the MSPs are expressed as an incremental cost increase 

over the baseline level, where the baseline MSP is assigned a value of $0. As a result, the 

average installed prices for Class A EPSs are not indicative of the total installed cost at each 

CSL, and thus the average LCC results are also not indicative of the total life-cycle cost for each 

CSL. However, the LCC savings, PBP calculations, and percentage of consumers with a net cost 

or net benefit are unaffected by using these MSPs since they consider the incremental change 

from one CSL to the other. 

As explained in chapter 5, several of the costs resulting from DOE’s teardown analysis 

resulted in a negative-sloping cost-efficiency curve. This indicates that a unit with a higher 

efficiency would have a lower purchase price than a unit with a lower efficiency. A negativesloping cost-efficiency curve will result in positive LCC savings at every standards-level because 

the consumer experiences both a lower installed cost and lower operating costs. Any LCC or 

PBP analysis on these units would indicate the highest CSL as having the greatest benefit to the 

consumer. Only the 60W EPS had a higher price for the best-in-market design (CSL 3) than for 

the baseline design (CSL 0), but this price was lower than the CSL 1 design’s price. While the 

results for the 60W test/teardown data look similar to the results using the manufacturer data, 

DOE only presents the manufacturer data since it does not contain any negative-sloping costefficiency curves. Similarly, DOE does not present LCC or PBP results for any test/teardown 

data collected for Class A EPSs, and defers to the data aggregated from manufacturer interviews. 

8-25 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

8.4.2.1 Base Case LCC Distributions (Manufacturer Data) 

Figure 8.5 through Figure 8.8 show the frequency charts for the base case LCC for the 

four Class A EPS representative units. Since the base case considers the different efficiency 

levels at which consumers currently purchase products, the base case LCC distribution is 

composed of several standards-levels. If all consumers purchased products at CSL 0 in the base 

case, then the LCC distribution would be composed entirely of the LCC at CSL 0. However, the 

LCC distribution in the base case shows the LCC results in proportion to how many users 

currently purchase products at each standards-level (CSLs 0 through 4). 

To find the appropriate distribution of LCCs in the base case, the total LCC was 

calculated for each standards-level considered (CSLs 0 through 4). Then these distributions were 

weighted by the market shares for each standards-level in the base case, as discussed in section 

8.2.10. The combined chart shows the aggregated LCC distribution across all CSLs in the base 

case. 

0%

1%

2%

3%

4%

5%

6%

7%

8%

0.100.300.600.801.001.301.501.702.002.202.502.702.903.203.403.603.90

Percent of Consumers (%)

Weighted Total LCC ($)

Total LCC in the Base Case 

(weighted by market distribution)

CSL 4

CSL 3

CSL 2

CSL 1

CSL 0

Figure 8.5 2.5W Regular AC/DC External Power Supplies: Base Case LCC Distribution 

(Manufacturer Data) 

8-26 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

0%

1%

2%

3%

4%

5%

6%

7%

8%

9%

0.301.302.403.504.605.706.807.808.90

10.00

11.10

12.2013.3014.3015.4016.5017.60

Percent of Consumers (%)

Weighted Total LCC ($)

Total LCC in the Base Case

(weighted by market distribution)

CSL 4

CSL 3

CSL 2

CSL 1

CSL 0

Figure 8.6 18W Regular AC/DC External Power Supplies: Base Case LCC Distribution 

(Manufacturer Data) 

0%

1%

2%

3%

4%

5%

6%

7%

8%

2.302.803.303.804.304.805.305.806.306.807.307.808.308.809.309.80

10.30

Percent of Consumers (%)

Weighted Total LCC ($)

Total LCC in the Base Case

(weighted by market distribution)

CSL 4

CSL 3

CSL 2

CSL 1

CSL 0

Figure 8.7 60W Regular AC/DC External Power Supplies: Base Case LCC Distribution 

(Manufacturer Data) 

8-27 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

0%

1%

2%

3%

4%

5%

6%

7%

8%

4.204.705.105.606.106.507.007.407.908.408.809.309.70

10.2010.70

11.1011.60

Percent of Consumers (%)

Weighted Total LCC ($)

Total LCC in the Base Case

(weighted by market distribution)

CSL 4

CSL 3

CSL 2

CSL 1

CSL 0

Figure 8.8 120W Regular AC/DC External Power Supplies: Base Case LCC Distribution 

(Manufacturer Data) 

8.4.2.2 2.5W Regular AC/DC External Power Supplies (Manufacturer Data) 

Figure 8.9 and Figure 8.10 show the distribution of LCC savings and PBPs for each CSL. 

th th In these figures, the ends of the box represent the 25 and 75 percentiles in the distribution, 

th th while the whiskers represent the 5 and 95 percentiles. A percentile represents the portion of 

sampled consumers that fall below a certain threshold. For example, an LCC savings value of 

$1.00 at the 25th percentile means that 25-percent of the sampled consumers will save $1.00. 

th th The bottom portion of the blue 25 percentile box and the top portion of the green 75 percentile 

th th box represent the 25 and 75 percentile values in the distribution. The figures also indicate the 

median and average value for each CSL. In the case of the PBP distribution, a small change in 

operating cost can occasionally result in a very large PBP. As a result, the upper whisker may 

become disproportionately long, skewing the average PBP value. For this reason, the median 

PBP is a better estimate of the actual PBP. 

8-28 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

-0.80

-0.60

-0.40

-0.20

0.00

0.20

0.40

0.60

0.80

1.00

1.20

CSL 1 CSL 2 CSL 3 CSL 4

Life-Cycle Cost Savings (2009$)

LCC Savings Ranges by Efficiency Level

Box 25% - 75%; Whisker: 5% - 95%

Median

Average

75th Percentile

25th Percentile

Figure 8.9 2.5W Regular AC/DC External Power Supplies: Distribution of Life-Cycle Cost 

Impacts (Manufacturer Data)
 

0.0

5.0

10.0

15.0

20.0

25.0

30.0

CSL 1 CSL 2 CSL 3 CSL 4

Payback Period (years)

PBP Ranges by Efficiency Level

Box 25% - 75%; Whisker: 5% - 95%

Median

Average

75th Percentile

25th Percentile

Figure 8.10 2.5W Regular AC/DC External Power Supplies: Distribution of PBPs 

(Manufacturer Data) 

8-29 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

 

 

 

Table 8.4.1 summarizes the LCC and PBP results for the 2.5W EPS. As mentioned 

earlier, for some consumers, DOE assigned products in the base case that are more energy 

efficient than some of the energy levels under consideration. For that reason, the average LCC 

impacts are not equal to the difference between the LCC of a specific energy efficiency level and 

the LCC of the baseline product. Similarly with regard to PBPs shown below, DOE determined 

the median and average values by excluding the percentage of consumers not impacted by a 

standard at a given efficiency level. The values for average operating cost in the table are 

discounted sums of the annual operating costs over the product lifetime. 

For 2.5W EPSs, CSL 1 has the highest average LCC savings and a median PBP of 0.4 

years. The majority of consumers (96.9-percent) are either not impacted by standard set at this 

level or benefit from this standard level, while only 3.1-percent of consumers experience a net 

cost. Each CSL has positive LCC savings, including CSL 4. Consumers are said to have ―no 

impact‖ if the base case forecast product assigned to them has a greater efficiency than the level 

indicated by a standard. 

Table 8.4.1 LCC and PBP Results for 2.5W Regular AC/DC External Power Supplies 

(Manufacturer Data) 

CSL Eff.* 

% 

No 

Load 

Power 

W 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Price† 

2009$ 

Avg. 

Operating 

Cost 

2009$ 

Avg. 

LCC† 

2009$ 

Wtd. 

Avg. 

Savings 

2009$ 

Consumers with 

Median 

yrs. 

Mean 

yrs. 

Net 

Cost 

% 

No 

Impact 

% 

Net 

Benefit 

% 

0 58.3 0.500 0.00 1.73 1.73 - - - - - -

1 67.9 0.300 0.06 1.12 1.19 0.19 3.1 66.0 30.9 0.4 1.3 

2 71.0 0.130 0.35 0.90 1.24 0.14 40.5 15.3 44.2 3.6 12.7 

3 73.5 0.100 0.47 0.78 1.25 0.13 44.2 3.2 52.6 3.7 12.7 

4 74.0 0.053 0.63 0.74 1.36 0.02 64.3 0.0 35.7 4.8 17.2 

* ―Eff.‖ stands for ―efficiency level.‖ 

† Based on an incremental MSP over the baseline. 

8.4.2.3 18W Regular AC/DC External Power Supplies (Manufacturer Data) 

Figure 8.11 and Figure 8.12 show the distribution of LCC savings and PBPs for each 

th th CSL. In these figures, the ends of the box represent the 25 and 75 percentiles in the 

th th distribution, while the whiskers represent the 5 and 95 percentiles. A percentile represents the 

portion of sampled consumers that fall below a certain threshold. For example, an LCC savings 

value of $1.00 at the 25th percentile means that 25-percent of the sampled consumers will save 

th th $1.00. The bottom portion of the blue 25 percentile box and the top portion of the green 75

th th percentile box represent the 25 and 75 percentile values in the distribution. The figures also 

indicate the median and average value for each CSL. In the case of the PBP distribution, a small 

change in operating cost can occasionally result in a very large PBP. As a result, the upper 

whisker may become disproportionately long, skewing the average PBP value. For this reason, 

the median PBP is a better estimate of the actual PBP. 

8-30 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

-2.00

-1.00

0.00

1.00

2.00

3.00

4.00

5.00

CSL 1 CSL 2 CSL 3

Life-Cycle Cost Savings (2009$)

LCC Savings Ranges by Efficiency Level

Box 25% - 75%; Whisker: 5% - 95%

Median

Average

75th Percentile

25th Percentile

Figure 8.11 18W Regular AC/DC External Power Supplies: Distribution of Life-Cycle 

Cost Impacts (Manufacturer Data)
 

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

CSL 1 CSL 2 CSL 3

Payback Period (years)

PBP Ranges by Efficiency Level

Box 25% - 75%; Whisker: 5% - 95%

Median

Average

75th Percentile

25th Percentile

Figure 8.12 18W Regular AC/DC External Power Supplies: Distribution of PBPs 

(Manufacturer Data) 

8-31 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 8.4.2 summarizes the LCC and PBP results for the 18W EPS. As mentioned 

earlier, for some consumers, DOE assigned products in the base case that are more energy 

efficient than some of the energy levels under consideration. For that reason, the average LCC 

impacts are not equal to the difference between the LCC of a specific energy efficiency level and 

the LCC of the baseline product. Similarly with regard to PBPs shown below, DOE determined 

the median and average values by excluding the percentage of consumers not impacted by a 

standard at a given efficiency level. The values for average operating cost in the table are 

discounted sums of the annual operating costs over the product lifetime. 

For 18W EPSs, CSL 3 has the highest average LCC savings and a median PBP of 1.5 

years. The majority of consumers (81.8-percent) are either not impacted by a standard set at this 

level (3.3-percent) or experience a net benefit at this level (78.5-percent). The maximum 

efficiency level considered, CSL 4, also has positive LCC savings and a median PBP of 2.1 

years. Consumers are said to have ―no impact‖ if the base case forecast product assigned to them 

has a greater efficiency than the level indicated by a standard. 

Table 8.4.2 LCC and PBP Results for 18W Regular AC/DC External Power Supplies 

(Manufacturer Data) 

CSL Eff.* 

% 

No 

Load 

Power 

W 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Price† 

2009$ 

Avg. 

Operating 

Cost 

2009$ 

Avg. 

LCC† 

2009$ 

Wtd. 

Avg. 

Savings 

2009$ 

Consumers with 

Median 

yrs. 

Mean 

yrs. 

Net 

Cost 

% 

No 

Impact 

% 

Net 

Benefit 

% 

0 76.0 0.500 0.00 6.54 6.54 - - - - - -

1 80.3 0.300 0.44 4.99 5.43 0.33 6.2 65.9 27.9 1.1 4.9 

2 83.0 0.200 0.59 4.11 4.70 0.96 11.5 15.3 73.2 0.8 2.8 

3 85.4 0.100 1.11 3.35 4.45 1.20 18.2 3.3 78.5 1.5 5.5 

4 87.5 0.062 1.73 2.79 4.52 1.13 33.5 0.0 66.5 2.1 8.0 

* ―Eff.‖ stands for ―efficiency level.‖ 

† Based on an incremental MSP over the baseline. 

8.4.2.4 60W Regular AC/DC External Power Supplies (Manufacturer Data) 

Figure 8.13 and Figure 8.14 show the distribution of LCC savings and PBPs for each 

th th CSL. In these figures, the ends of the box represent the 25 and 75 percentiles in the 

th th distribution, while the whiskers represent the 5 and 95 percentiles. A percentile represents the 

portion of sampled consumers that fall below a certain threshold. For example, an LCC savings 

value of $1.00 at the 25th percentile means that 25-percent of the sampled consumers will save 

th th $1.00. The bottom portion of the blue 25 percentile box and the top portion of the green 75

th th percentile box represent the 25 and 75 percentile values in the distribution. The figures also 

indicate the median and average value for each CSL. In the case of the PBP distribution, a small 

change in operating cost can occasionally result in a very large PBP. As a result, the upper 

whisker may become disproportionately long, skewing the average PBP value. For this reason, 

the median PBP is a better estimate of the actual PBP. 

8-32 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

-3.00

-2.50

-2.00

-1.50

-1.00

-0.50

0.00

0.50

1.00

CSL 1 CSL 2 CSL 3

Life-Cycle Cost Savings (2009$)

LCC Savings Ranges by Efficiency Level

Box 25% - 75%; Whisker: 5% - 95%

Median

Average

75th Percentile

25th Percentile

Figure 8.13 60W Regular AC/DC External Power Supplies: Distribution of Life-Cycle 

Cost Impacts (Manufacturer Data)
 

0.0

2.0

4.0

6.0

8.0

10.0

12.0

CSL 1 CSL 2 CSL 3

Payback Period (years)

PBP Ranges by Efficiency Level

Box 25% - 75%; Whisker: 5% - 95%

Median

Average

75th Percentile

25th Percentile

Figure 8.14 60W Regular AC/DC External Power Supplies: Distribution of PBPs 

(Manufacturer Data) 

8-33 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

 

 

 

 

Table 8.4.3 summarizes the LCC and PBP results for the 60W EPS. As mentioned 

earlier, for some consumers, DOE assigned products in the base case that are more energy 

efficient than some of the energy levels under consideration. For that reason, the average LCC 

impacts are not equal to the difference between the LCC of a specific energy efficiency level and 

the LCC of the baseline product. Similarly with regard to PBPs shown below, DOE determined 

the median and average values by excluding the percentage of consumers not impacted by a 

standard at a given efficiency level. The values for average operating cost in the table are 

discounted sums of the annual operating costs over the product lifetime. 

For 60W EPSs, CSL 2 has the highest average LCC savings and a median PBP of 3.6 

years. At this CSL, approximately 50.0-percent of consumer experience a net cost, but the 

remaining 50.0-percent either experience no impact (15.3-percent) or a net benefit (34.7-percent) 

by a standard set at this level. Consumers are said to have ―no impact‖ if the base case forecast 

product assigned to them has a greater efficiency than the level indicated by a standard. 

Table 8.4.3 LCC and PBP Results for 60W Regular AC/DC External Power Supplies 

(Manufacturer Data) 

CSL Eff.* 

% 

No 

Load 

Power 

W 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Price† 

2009$ 

Avg. 

Operating 

Cost 

2009$ 

Avg. 

LCC† 

2009$ 

Wtd. 

Avg. 

Savings 

2009$ 

Consumers with 

Median 

yrs. 

Mean 

yrs. 

Net 

Cost 

% 

No 

Impact 

% 

Net 

Benefit 

% 

0 85.0 0.500 0.00 4.63 4.63 - - - - - -

1 87.0 0.500 0.34 4.08 4.43 0.07 4.8 66.0 29.2 2.4 2.4 

2 87.0 0.200 1.02 3.43 4.46 0.05 50.0 15.3 34.7 3.6 3.6 

3 88.0 0.073 2.28 2.90 5.18 -0.65 88.5 3.3 8.2 5.8 6.0 

4 91.0 0.073 4.18 2.13 6.31 -1.78 96.7 0.0 3.3 7.2 7.2 

* ―Eff.‖ stands for ―efficiency level.‖ 

† Based on an incremental MSP over the baseline. 

8.4.2.5 120W Regular AC/DC External Power Supplies (Manufacturer Data) 

Figure 8.15 and Figure 8.16 show the distribution of LCC savings and PBPs for each 

th th CSL. In these figures, the ends of the box represent the 25 and 75 percentiles in the 

th th distribution, while the whiskers represent the 5 and 95 percentiles. A percentile represents the 

portion of sampled consumers that fall below a certain threshold. For example, an LCC savings 

value of $1.00 at the 25th percentile means that 25-percent of the sampled consumers will save 

th th $1.00. The bottom portion of the blue 25 percentile box and the top portion of the green 75

th th percentile box represent the 25 and 75 percentile values in the distribution. The figures also 

indicate the median and average value for each CSL. In the case of the PBP distribution, a small 

change in operating cost can occasionally result in a very large PBP. As a result, the upper 

whisker may become disproportionately long, skewing the average PBP value. For this reason, 

the median PBP is a better estimate of the actual PBP. 

8-34 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

-5.00

-4.00

-3.00

-2.00

-1.00

0.00

1.00

2.00

CSL 1 CSL 2 CSL 3

Life-Cycle Cost Savings (2009$)

LCC Savings Ranges by Efficiency Level

Box 25% - 75%; Whisker: 5% - 95%

Median

Average

75th Percentile

25th Percentile

Figure 8.15 120W Regular AC/DC External Power Supplies: Distribution of Life-Cycle 

Cost Impacts (Manufacturer Data)
 

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

CSL 1 CSL 2 CSL 3

Payback Period (years)

PBP Ranges by Efficiency Level

Box 25% - 75%; Whisker: 5% - 95%

Median

Average

75th Percentile

25th Percentile

Figure 8.16 120W Regular AC/DC External Power Supplies: Distribution of PBPs 

(Manufacturer Data) 

8-35 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

 

 

 

 

Table 8.4.4 summarizes the LCC and PBP results for the 120W EPS. As mentioned 

earlier, for some consumers, DOE assigned products in the base case that are more energy 

efficient than some of the energy levels under consideration. For that reason, the average LCC 

impacts are not equal to the difference between the LCC of a specific energy efficiency level and 

the LCC of the baseline product. Similarly with regard to PBPs shown below, DOE determined 

the median and average values by excluding the percentage of consumers not impacted by a 

standard at a given efficiency level. The values for average operating cost in the table are 

discounted sums of the annual operating costs over the product lifetime. 

For 120W EPSs, CSL 2 has the highest average LCC savings and a median PBP of 3.0 

years. The majority of consumers (55.3-percent) either experience no impact (15.2-percent) or a 

net benefit (40.1-percent) from a standard set at this level. CSL 3 also has positive LCC savings, 

and a median PBP of 3.3 years. Consumers are said to have ―no impact‖ if the base case forecast 

product assigned to them has a greater efficiency than the level indicated by a standard. 

Table 8.4.4 LCC and PBP Results for 120W Regular AC/DC External Power Supplies 

(Manufacturer Data) 

CSL Eff.* 

% 

No 

Load 

Power 

W 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Price† 

2009$ 

Avg. 

Operating 

Cost 

2009$ 

Avg. 

LCC† 

2009$ 

Wtd. 

Avg. 

Savings 

2009$ 

Consumers with 

Median 

yrs. 

Mean 

yrs. 

Net 

Cost 

% 

No 

Impact 

% 

Net 

Benefit 

% 

0 85.0 0.500 0.00 6.48 6.48 - - - - - -

1 87.0 0.500 0.92 5.62 6.54 -0.02 24.7 66.1 9.2 3.6 3.4 

2 88.0 0.230 1.72 4.73 6.45 0.05 44.7 15.2 40.1 3.0 2.9 

3 88.4 0.210 1.97 4.53 6.50 0.01 63.1 3.2 33.7 3.3 3.2 

4 91.7 0.165 7.05 3.15 10.20 -3.69 99.8 0.0 0.2 7.6 7.8 

* ―Eff.‖ stands for ―efficiency level.‖ 

† Based on an incremental MSP over the baseline. 

8.4.3 Battery Charger Results (Representative Units) 

DOE conducted a life-cycle cost analysis on six representative units for BCs at different 

combinations of battery energy and battery voltage, one for each of the six representative product 

classes: low energy, inductive charge; low energy, low voltage; low energy, high voltage; 

medium energy, low voltage; high energy; and low energy, AC out. As discussed in chapter 5, 

when possible, DOE created two sets of cost-efficiency curves for each of the six representative 

units using data from manufacturer interviews and data from DOE’s own tests/teardowns. For 

some representative units, however, insufficient data was available to create a cost-efficiency 

curve from tests/teardowns. In these cases, DOE only presents a single cost-efficiency curve 

from its appropriate source. 

Unlike the EPSs discussed previously, the MSPs for each efficiency level considered in 

the BC analysis represent the total MSP attributable to a product, not the incremental MSP over a 

baseline level. As such, the average installed prices can be interpreted as the total installed cost 

at each CSL, and the total life-cycle cost is representative of the actual cost associated with the 

product. The LCC savings, PBP calculations, and percentage of consumers with a net cost or net 

benefit are unaffected by the type of MSP used, and thus remain accurate. 

8-36 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

8.4.3.1 Base Case LCC Distributions (Manufacturer Data) 

Figure 8.17 through Figure 8.22 show the frequency charts for the base case LCC for the 

six BC representative units using manufacturer data. Since the base case considers the different 

efficiency levels at which consumers currently purchase products, the base case LCC distribution 

is composed of several standards-levels. If all consumers purchased products at CSL 0 in the 

base case, then the LCC distribution would be composed entirely of the LCC at CSL 0. 

However, the LCC distribution in the base case shows the LCC results in proportion to how 

many users currently purchase products at each standards-level (CSLs 0 through 3). 

To find the appropriate distribution of LCCs in the base case, the total LCC was 

calculated for each standards-level considered (CSLs 0 through 3). Then these distributions were 

weighted by the market shares for each standards-level in the base case, as discussed in section 

8.2.10. The combined chart shows the aggregated LCC distribution across all CSLs in the base 

case. 

0%

1%

2%

3%

4%

5%

6%

7%

5.606.006.406.807.207.708.108.508.909.309.80

10.2010.60

11.0011.5011.90

12.30

Percent of Consumers (%)

Weighted Total LCC ($)

Total LCC in the Base Case

(weighted by market distribution)

CSL 3

CSL 2

CSL 1

CSL 0

Figure 8.17 Low Energy, Inductive Battery Charger: Base Case LCC Distribution 

(Manufacturer Data) 

8-37 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

0%

5%

10%

15%

20%

25%

30%

35%

0.001.202.403.504.705.907.108.309.50

10.60

11.80

13.0014.2015.4016.6017.7018.90

Percent of Consumers (%)

Weighted Total LCC ($)

Total LCC in the Base Case

(weighted by market distribution)

CSL 3

CSL 2

CSL 1

CSL 0

Figure 8.18 Low Energy, Low Voltage Battery Charger: Base Case LCC Distribution 

(Manufacturer Data) 

0%

5%

10%

15%

20%

25%

Percent of Consumers (%)

Weighted Total LCC ($)

Total LCC in the Base Case

(weighted by market distribution)

CSL 3

CSL 2

CSL 1

CSL 0

Figure 8.19 Low Energy, High Voltage Battery Charger: Base Case LCC Distribution 

(Manufacturer Data) 

8-38 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

0%

1%

2%

3%

4%

5%

6%

7%

8%

9%

Percent of Consumers (%)

Weighted Total LCC ($)

Total LCC in the Base Case

(weighted by market distribution)

CSL 3

CSL 2

CSL 1

CSL 0

Figure 8.20 Medium Energy, Low Voltage Battery Charger: Base Case LCC Distribution 

(Manufacturer Data) 

0%

1%

2%

3%

4%

5%

6%

7%

299.80312.90326.10339.20352.30365.40378.60391.70404.80417.90431.00444.20457.30470.40483.50496.70509.80

Percent of Consumers (%)

Weighted Total LCC ($)

Total LCC in the Base Case

(weighted by market distribution)

CSL 3

CSL 2

CSL 1

CSL 0

Figure 8.21 High Energy Battery Charger: Base Case LCC Distribution (Manufacturer
 

Data)
 

8-39 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

0%

1%

2%

3%

4%

5%

6%

7%

9.20

10.10

11.00

12.0012.9013.9014.8015.8016.7017.7018.6019.6020.5021.4022.4023.3024.30

Percent of Consumers (%)

Weighted Total LCC ($)

Total LCC in the Base Case

(weighted by market distribution)

CSL 3

CSL 2

CSL 1

CSL 0

Figure 8.22 Low Energy, AC Out Battery Charger: Base Case LCC Distribution 

(Manufacturer Data) 

8.4.3.2 Base Case LCC Distributions (Test/Teardown Data) 

Figure 8.23 through Figure 8.26 show the frequency charts for the base case LCC for four 

of the BC representative units using test/teardown data. DOE only had sufficient test/teardown 

data for four of the six BC representative units. Since the base case considers the different 

efficiency levels at which consumers currently purchase products, the base case LCC distribution 

is composed of several standards-levels. If all consumers purchased products at CSL 0 in the 

base case, then the LCC distribution would be composed entirely of the LCC at CSL 0. 

However, the LCC distribution in the base case shows the LCC results in proportion to how 

many users currently purchase products at each standards-level (CSLs 0 through 3). 

To find the appropriate distribution of LCCs in the base case, the total LCC was 

calculated for each standards-level considered (CSLs 0 through 3). Then these distributions were 

weighted by the market shares for each standards-level in the base case, as discussed in section 

8.2.10. The combined chart shows the aggregated LCC distribution across all CSLs in the base 

case. 

8-40 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

0%

2%

4%

6%

8%

10%

12%

14%

16%

18%

1.602.002.402.803.203.604.004.404.805.205.606.006.406.807.207.608.008.408.809.209.60

10.00

Percent of Consumers (%)

Weighted Total LCC ($)

Total LCC in the Base Case

(weighted by market distribution)

CSL 3

CSL 2

CSL 1

CSL 0

Figure 8.23 Low Energy, Low Voltage Battery Charger: Base Case LCC Distribution 

(Test/Teardown Data) 

0%

5%

10%

15%

20%

25%

30%

8.60

10.3012.0013.8015.5017.2018.9020.7022.4024.1025.8027.5029.3031.0032.7034.4036.1037.9039.6041.3043.00

Percent of Consumers (%)

Weighted Total LCC ($)

Total LCC in the Base Case

(weighted by market distribution)

CSL 3

CSL 2

CSL 1

CSL 0

Figure 8.24 Low Energy, High Voltage Battery Charger: Base Case LCC Distribution 

(Test/Teardown Data) 

8-41 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

0%

2%

4%

6%

8%

10%

12%

14%

70.2081.9093.60

105.30

117.00

128.70140.40152.10163.80175.50187.30199.00210.70222.40234.10245.80257.50269.20280.90292.60

Percent of Consumers (%)

Weighted Total LCC ($)

Total LCC in the Base Case

(weighted by market distribution)

CSL 3

CSL 2

CSL 1

CSL 0

Figure 8.25 Medium Energy, Low Voltage Battery Charger: Base Case LCC Distribution 

(Test/Teardown Data) 

0%

1%

2%

3%

4%

5%

6%

7%

8%

9%

10%

5.506.507.508.509.50

10.50

11.50

12.5013.5014.4015.4016.4017.4018.4019.4020.4021.4022.4023.4024.40

Percent of Consumers (%)

Weighted Total LCC ($)

Total LCC in the Base Case

(weighted by market distribution)

CSL 3

CSL 2

CSL 1

CSL 0

Figure 8.26 Low Energy, AC Out Battery Charger: Base Case LCC Distribution 

(Test/Teardown Data) 

8-42 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

8.4.3.3 Low Energy, Inductive Battery Chargers (Manufacturer Data) 

Figure 8.27 and Figure 8.28 show the distribution of LCC savings and PBPs for each 

th th CSL. In these figures, the ends of the box represent the 25 and 75 percentiles in the 

th th distribution, while the whiskers represent the 5 and 95 percentiles. A percentile represents the 

portion of sampled consumers that fall below a certain threshold. For example, an LCC savings 

value of $1.00 at the 25th percentile means that 25-percent of the sampled consumers will save 

th th $1.00. The bottom portion of the blue 25 percentile box and the top portion of the green 75

th th percentile box represent the 25 and 75 percentile values in the distribution. The figures also 

indicate the median and average value for each CSL. In the case of the PBP distribution, a small 

change in operating cost can occasionally result in a very large PBP. As a result, the upper 

whisker may become disproportionately long, skewing the average PBP value. For this reason, 

the median PBP is a better estimate of the actual PBP. 

0.00

1.00

2.00

3.00

4.00

5.00

6.00

CSL 1 CSL 2 CSL 3

Life-Cycle Cost Savings (2009$)

LCC Savings Ranges by Efficiency Level

Box 25% - 75%; Whisker: 5% - 95%

Median

Average

75th Percentile

25th Percentile

Figure 8.27 Low Energy, Inductive Battery Chargers: Distribution of Life-Cycle Cost 

Impacts (Manufacturer Data)
 

8-43 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

0.0

0.2

0.4

0.6

0.8

1.0

1.2

CSL 1 CSL 2 CSL 3

Payback Period (years)

PBP Ranges by Efficiency Level

Box 25% - 75%; Whisker: 5% - 95%

Median

Average

75th Percentile

25th Percentile

Figure 8.28 Low Energy, Inductive Battery Chargers: Distribution of PBPs (Manufacturer 

Data) 

Table 8.4.5 summarizes the LCC and PBP results for the low energy, inductive BC. As 

mentioned earlier, for some consumers, DOE assigned products in the base case that are more 

energy efficient than some of the energy levels under consideration. For that reason, the average 

LCC impacts are not equal to the difference between the LCC of a specific energy efficiency 

level and the LCC of the baseline product. Similarly with regard to PBPs shown below, DOE 

determined the median and average values by excluding the percentage of consumers not 

impacted by a standard at a given efficiency level. The values for average operating cost in the 

table are discounted sums of the annual operating costs over the product lifetime. 

For low energy, inductive BCs, CSL 3 has the highest average LCC savings and a median 

PBP of 0.9 years. Every consumer (100.0-percent) experiences a net benefit at this level. 

Consumers are said to have ―no impact‖ if the base case forecast product assigned to them has a 

greater efficiency than the level indicated by a standard. 

8-44 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

Table 8.4.5 LCC and PBP Results for Low Energy, Inductive Battery Chargers 

(Manufacturer Data) 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Avg. 

Operating Avg. 

Wtd. 

Avg. 

Consumers with 

Net No Net 

CSL UEC Price Cost LCC Savings Cost Impact Benefit Median Mean 

kWh 2009$ 2009$ 2009$ 2009$ % % % yrs. yrs. 

0 10.0 4.39 4.81 9.20 - - - - - -

1 7.0 4.61 3.37 7.97 0.93 0.0 24.9 75.1 0.7 0.7 

2 3.5 4.91 1.68 6.59 2.14 0.0 12.4 87.6 0.8 0.8 

3 1.5 5.12 0.72 5.84 2.90 0.0 0.0 100.0 0.9 0.8 

8.4.3.4 Low Energy, Inductive Battery Chargers (Test/Teardown Data) 

DOE did not have sufficient test/teardown data to perform an LCC analysis of the low 

energy, inductive representative unit. Section 8.4.3.3 contains LCC and PBP results for this 

representative unit using manufacturer data. 

8.4.3.5 Low Energy, Low Voltage Battery Chargers (Manufacturer Data) 

Figure 8.29 and Figure 8.30 show the distribution of LCC savings and PBPs for each 

th th CSL. In these figures, the ends of the box represent the 25 and 75 percentiles in the 

th th distribution, while the whiskers represent the 5 and 95 percentiles. A percentile represents the 

portion of sampled consumers that fall below a certain threshold. For example, an LCC savings 

value of $1.00 at the 25th percentile means that 25-percent of the sampled consumers will save 

th th $1.00. The bottom portion of the blue 25 percentile box and the top portion of the green 75

th th percentile box represent the 25 and 75 percentile values in the distribution. The figures also 

indicate the median and average value for each CSL. In the case of the PBP distribution, a small 

change in operating cost can occasionally result in a very large PBP. As a result, the upper 

whisker may become disproportionately long, skewing the average PBP value. For this reason, 

the median PBP is a better estimate of the actual PBP. 

8-45 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

-18.00

-16.00

-14.00

-12.00

-10.00

-8.00

-6.00

-4.00

-2.00

0.00

2.00

4.00

CSL 1 CSL 2

Life-Cycle Cost Savings (2009$)

LCC Savings Ranges by Efficiency Level

Box 25% - 75%; Whisker: 5% - 95%

Median

Average

75th Percentile

25th Percentile

Figure 8.29 Low Energy, Low Voltage Battery Chargers: Distribution of Life-Cycle Cost 

Impacts (Manufacturer Data)
 

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

160.0

180.0

CSL 1 CSL 2

Payback Period (years)

PBP Ranges by Efficiency Level

Box 25% - 75%; Whisker: 5% - 95%

Median

Average

75th Percentile

25th Percentile

Figure 8.30 Low Energy, Low Voltage Battery Chargers: Distribution of PBPs 

(Manufacturer Data) 

Table 8.4.6 summarizes the LCC and PBP results for the low energy, low voltage BC. 

As mentioned earlier, for some consumers, DOE assigned products in the base case that are more 

8-46 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

 

 

energy efficient than some of the energy levels under consideration. For that reason, the average 

LCC impacts are not equal to the difference between the LCC of a specific energy efficiency 

level and the LCC of the baseline product. Similarly with regard to PBPs shown below, DOE 

determined the median and average values by excluding the percentage of consumers not 

impacted by a standard at a given efficiency level. The values for average operating cost in the 

table are discounted sums of the annual operating costs over the product lifetime. 

For low energy, low voltage BCs, CSL 1 has the highest average LCC savings ($0.20) 

and a median PBP of 1.5 years. The majority of consumers (60.8-percent) are not impacted by a 

standard set at this level, but 32.6-percent of consumers experience a net benefit. Consumers are 

said to have ―no impact‖ if the base case forecast product assigned to them has a greater 

efficiency than the level indicated by a standard. 

Table 8.4.6 LCC and PBP Results for Low Energy, Low Voltage Battery Chargers 

(Manufacturer Data) 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Avg. 

Operating Avg. 

Wtd. 

Avg. 

Consumers with 

Net No Net 

CSL UEC Price Cost LCC Savings Cost Impact Benefit Median Mean 

kWh 2009$ 2009$ 2009$ 2009$ % % % yrs. yrs. 

0 10.0 1.42 3.30 4.72 - - - - - -

1 6.0 2.13 2.08 4.20 0.20 6.6 60.8 32.6 1.5 2.2 

2 1.2 18.09 0.46 18.54 -13.74 97.2 2.8 0.0 25.4 38.9 

8.4.3.6 Low Energy, Low Voltage Battery Chargers (Test/Teardown Data) 

Figure 8.31 through Figure 8.32 show the distribution of LCC savings and PBPs for each 

th th CSL. In these figures, the ends of the box represent the 25 and 75 percentiles in the 

th th distribution, while the whiskers represent the 5 and 95 percentiles. A percentile represents the 

portion of sampled consumers that fall below a certain threshold. For example, an LCC savings 

value of $1.00 at the 25th percentile means that 25-percent of the sampled consumers will save 

th th $1.00. The bottom portion of the blue 25 percentile box and the top portion of the green 75

th th percentile box represent the 25 and 75 percentile values in the distribution. The figures also 

indicate the median and average value for each CSL. In the case of the PBP distribution, a small 

change in operating cost can occasionally result in a very large PBP. As a result, the upper 

whisker may become disproportionately long, skewing the average PBP value. For this reason, 

the median PBP is a better estimate of the actual PBP. 

For the low energy, low voltage representative unit, DOE did not have sufficient 

test/teardown data to accurately evaluate a baseline unit (CSL 0). For this reason, the figures 

show a mean and median value of $0 and 0 years for the LCC savings and PBP, respectively. 

For additional analyses of the baseline CSL for this representative unit, please see section 

8.4.3.5. 

8-47 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

-3.00

-2.00

-1.00

0.00

1.00

2.00

3.00

CSL 1 CSL 2

Life-Cycle Cost Savings (2009$)

LCC Savings Ranges by Efficiency Level

Box 25% - 75%; Whisker: 5% - 95%

Median

Average

75th Percentile

25th Percentile

Figure 8.31 Low Energy, Low Voltage Battery Chargers: Distribution of Life-Cycle Cost 

Impacts (Test/Teardown Data)
 

0.0

5.0

10.0

15.0

20.0

25.0

30.0

CSL 1 CSL 2

Payback Period (years)

PBP Ranges by Efficiency Level

Box 25% - 75%; Whisker: 5% - 95%

Median

Average

75th Percentile

25th Percentile

Figure 8.32 Low Energy, Low Voltage Battery Chargers: Distribution of PBPs 

(Test/Teardown Data) 

Table 8.4.7 summarizes the LCC and PBP results for the low energy, low voltage BC 

using test/teardown data. As mentioned earlier, for some consumers, DOE assigned products in 

8-48 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

the base case that are more energy efficient than some of the energy levels under consideration. 

For that reason, the average LCC impacts are not equal to the difference between the LCC of a 

specific energy efficiency level and the LCC of the baseline product. Similarly with regard to 

PBPs shown below, DOE determined the median and average values by excluding the 

percentage of consumers not impacted by a standard at a given efficiency level. The values for 

average operating cost in the table are discounted sums of the annual operating costs over the 

product lifetime. 

For low energy, low voltage BCs, CSL 1 is evaluated as the baseline unit since DOE did 

not have sufficient test/teardown data to evaluate a unit at CSL 0. The only standard level that 

was evaluated was CSL 2, which has negative LCC savings of -$0.90 and a median PBP of 4.7 

years. Consumers are said to have ―no impact‖ if the base case forecast product assigned to them 

has a greater efficiency than the level indicated by a standard. 

Table 8.4.7 LCC and PBP Results for Low Energy, Low Voltage Battery Chargers 

(Test/Teardown Data) 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Avg. 

Operating Avg. 

Wtd. 

Avg. 

Consumers with 

Net No Net 

CSL UEC Price Cost LCC Savings Cost Impact Benefit Median Mean 

kWh 2009$ 2009$ 2009$ 2009$ % % % yrs. yrs. 

0 10.0 N/A N/A N/A N/A N/A N/A N/A N/A N/A 

1 6.0 1.42 2.48 3.90 - - - - - -

2 1.2 4.43 0.38 4.82 -0.90 73.7 2.8 23.5 4.7 6.7 

8.4.3.7 Low Energy, High Voltage Battery Chargers (Manufacturer Data) 

Figure 8.33 and Figure 8.34 show the distribution of LCC savings and PBPs for each 

th th CSL. In these figures, the ends of the box represent the 25 and 75 percentiles in the 

th th distribution, while the whiskers represent the 5 and 95 percentiles. A percentile represents the 

portion of sampled consumers that fall below a certain threshold. For example, an LCC savings 

value of $1.00 at the 25th percentile means that 25-percent of the sampled consumers will save 

th th $1.00. The bottom portion of the blue 25 percentile box and the top portion of the green 75

th th percentile box represent the 25 and 75 percentile values in the distribution. The figures also 

indicate the median and average value for each CSL. At CSL 1, there is no box present because 

th th both the 25 and 75 percentiles equal 0, represented by the median. In the case of the PBP 

distribution, a small change in operating cost can occasionally result in a very large PBP. As a 

result, the upper whisker may become disproportionately long, skewing the average PBP value. 

For this reason, the median PBP is a better estimate of the actual PBP. 

8-49 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

-6.00

-4.00

-2.00

0.00

2.00

4.00

6.00

CSL 1 CSL 2

Life-Cycle Cost Savings (2009$)

LCC Savings Ranges by Efficiency Level

Box 25% - 75%; Whisker: 5% - 95%

Median

Average

75th Percentile

25th Percentile

Figure 8.33 Low Energy, High Voltage BC: Distribution of Life-Cycle Cost Impacts 

(Manufacturer Data) 

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

20.0

CSL 1 CSL 2

Payback Period (years)

PBP Ranges by Efficiency Level

Box 25% - 75%; Whisker: 5% - 95%

Median

Average

75th Percentile

25th Percentile

Figure 8.34 Low Energy, High Voltage BC: Distribution of PBPs (Manufacturer Data) 

Table 8.4.8 summarizes the LCC and PBP results for the low energy, high voltage BC. 

As mentioned earlier, for some consumers, DOE assigned products in the base case that are more 

energy efficient than some of the energy levels under consideration. For that reason, the average 

8-50 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

 

LCC impacts are not equal to the difference between the LCC of a specific energy efficiency 

level and the LCC of the baseline product. Similarly with regard to PBPs shown below, DOE 

determined the median and average values by excluding the percentage of consumers not 

impacted by a standard at a given efficiency level. The values for average operating cost in the 

table are discounted sums of the annual operating costs over the product lifetime. 

For low energy, high voltage BCs, CSL 1 has the highest average LCC savings ($0.97) 

and a median PBP of 3.4 years. The majority of consumers (81.3-percent) are not impacted by a 

standard set at this level. Consumers are said to have ―no impact‖ if the base case forecast 

product assigned to them has a greater efficiency than the level indicated by a standard. 

Table 8.4.8 LCC and PBP Results for Low Energy, High Voltage Battery Chargers 

(Manufacturer Data) 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Avg. 

Operating Avg. 

Wtd. 

Avg. 

Consumers with 

Net No Net 

CSL UEC Price Cost LCC Savings Cost Impact Benefit Median Mean 

kWh 2009$ 2009$ 2009$ 2009$ % % % yrs. yrs. 

0 39.4 8.04 16.65 24.69 - - - - - -

1 10.5 16.13 4.31 20.44 0.97 9.0 81.3 9.7 3.4 3.1 

2 6.1 20.60 2.48 23.08 -0.65 53.8 38.3 7.9 9.3 9.1 

8.4.3.8 Low Energy, High Voltage Battery Chargers (Test/Teardown Data) 

Figure 8.35 and Figure 8.36 show the distribution of LCC savings and PBPs for each 

th th CSL. In these figures, the ends of the box represent the 25 and 75 percentiles in the 

th th distribution, while the whiskers represent the 5 and 95 percentiles. A percentile represents the 

portion of sampled consumers that fall below a certain threshold. For example, an LCC savings 

value of $1.00 at the 25th percentile means that 25-percent of the sampled consumers will save 

th th $1.00. The bottom portion of the blue 25 percentile box and the top portion of the green 75

th th percentile box represent the 25 and 75 percentile values in the distribution. The figures also 

indicate the median and average value for each CSL. At CSL 1, there is no box present because 

th th both the 25 and 75 percentiles equal 0, represented by the median. In the case of the PBP 

distribution, a small change in operating cost can occasionally result in a very large PBP. As a 

result, the upper whisker may become disproportionately long, skewing the average PBP value. 

For this reason, the median PBP is a better estimate of the actual PBP. 

8-51 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

-2.00

0.00

2.00

4.00

6.00

8.00

10.00

CSL 1 CSL 2

Life-Cycle Cost Savings (2009$)

LCC Savings Ranges by Efficiency Level

Box 25% - 75%; Whisker: 5% - 95%

Median

Average

75th Percentile

25th Percentile

Figure 8.35 Low Energy, High Voltage BC: Distribution of Life-Cycle Cost Impacts 

(Test/Teardown Data) 

0.0

1.0

2.0

3.0

4.0

5.0

6.0

CSL 1 CSL 2

Payback Period (years)

PBP Ranges by Efficiency Level

Box 25% - 75%; Whisker: 5% - 95%

Median

Average

75th Percentile

25th Percentile

Figure 8.36 Low Energy, High Voltage BC: Distribution of PBPs (Test/Teardown Data) 

Table 8.4.9 summarizes the LCC and PBP results for the low energy, high voltage BC 

using the test/teardown data. As mentioned earlier, for some consumers, DOE assigned products 

in the base case that are more energy efficient than some of the energy levels under 

8-52 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

consideration. For that reason, the average LCC impacts are not equal to the difference between 

the LCC of a specific energy efficiency level and the LCC of the baseline product. Similarly 

with regard to PBPs shown below, DOE determined the median and average values by excluding 

the percentage of consumers not impacted by a standard at a given efficiency level. The values 

for average operating cost in the table are discounted sums of the annual operating costs over the 

product lifetime. 

For low energy, high voltage BCs, CSL 2 has the highest average LCC savings ($1.74) 

and a median PBP of 1.5 years. Over half of all consumers (50.7-percent) experience a net 

benefit from a standard set at this level, and an additional 38.2-percent of consumers already 

purchase products at CSL 2 and would therefore experience no impact from a standard at this 

level. Consumers are said to have ―no impact‖ if the base case forecast product assigned to them 

has a greater efficiency than the level indicated by a standard. 

Table 8.4.9 LCC and PBP Results for Low Energy, High Voltage Battery Chargers 

(Test/Teardown) 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Avg. 

Operating Avg. 

Wtd. 

Avg. 

Consumers with 

Net No Net 

CSL UEC Price Cost LCC Savings Cost Impact Benefit Median Mean 

kWh 2009$ 2009$ 2009$ 2009$ % % % yrs. yrs. 

0 39.4 8.04 15.38 23.42 - - - - - -

1 10.5 12.23 4.14 16.38 1.33 0.4 81.5 18.1 1.3 1.6 

2 6.1 13.20 2.52 15.72 1.74 11.1 38.2 50.7 1.5 2.5 

8.4.3.9 Medium Energy, Low Voltage Battery Chargers (Manufacturer Data) 

Figure 8.37 and Figure 8.38 show the distribution of LCC savings and PBPs for each 

th th CSL. In these figures, the ends of the box represent the 25 and 75 percentiles in the 

th th distribution, while the whiskers represent the 5 and 95 percentiles. A percentile represents the 

portion of sampled consumers that fall below a certain threshold. For example, an LCC savings 

value of $1.00 at the 25th percentile means that 25-percent of the sampled consumers will save 

th th $1.00. The bottom portion of the blue 25 percentile box and the top portion of the green 75

th th percentile box represent the 25 and 75 percentile values in the distribution. The figures also 

indicate the median and average value for each CSL. In the case of the PBP distribution, a small 

change in operating cost can occasionally result in a very large PBP. As a result, the upper 

whisker may become disproportionately long, skewing the average PBP value. For this reason, 

the median PBP is a better estimate of the actual PBP. 

8-53 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

-140.00

-120.00

-100.00

-80.00

-60.00

-40.00

-20.00

0.00

20.00

40.00

CSL 1 CSL 2 CSL 3

Life-Cycle Cost Savings (2009$)

LCC Savings Ranges by Efficiency Level

Box 25% - 75%; Whisker: 5% - 95%

Median

Average

75th Percentile

25th Percentile

Figure 8.37 Medium Energy, Low Voltage Battery Chargers: Distribution of Life-Cycle 

Cost Impacts (Manufacturer Data)
 

0.0

50.0

100.0

150.0

200.0

250.0

300.0

CSL 1 CSL 2 CSL 3

Payback Period (years)

PBP Ranges by Efficiency Level

Box 25% - 75%; Whisker: 5% - 95%

Median

Average

75th Percentile

25th Percentile

Figure 8.38 Medium Energy, Low Voltage Battery Chargers: Distribution of PBPs 

(Manufacturer Data) 

Table 8.4.10 summarizes the LCC and PBP results for the medium energy, low voltage 

BC. As mentioned earlier, for some consumers, DOE assigned products in the base case that are 

8-54 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

more energy efficient than some of the energy levels under consideration. For that reason, the 

average LCC impacts are not equal to the difference between the LCC of a specific energy 

efficiency level and the LCC of the baseline product. Similarly with regard to PBPs shown 

below, DOE determined the median and average values by excluding the percentage of 

consumers not impacted by a standard at a given efficiency level. The values for average 

operating cost in the table are discounted sums of the annual operating costs over the product 

lifetime. 

For medium energy, low voltage BCs, CSL 1 has the highest average LCC savings 

($2.08) and a median PBP of 2.4 years. Over half of all consumers (56.9-percent) are not 

impacted by a standard set at this level, and 33.1-percent of consumers experience a net benefit 

at this level. Consumers are said to have ―no impact‖ if the base case forecast product assigned 

to them has a greater efficiency than the level indicated by a standard. 

Table 8.4.10 LCC and PBP Results for Medium Energy, Low Voltage Battery Chargers 

(Manufacturer Data) 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Avg. 

Operating Avg. 

Wtd. 

Avg. 

Consumers with 

Net No Net 

CSL UEC Price Cost LCC Savings Cost Impact Benefit Median Mean 

kWh 2009$ 2009$ 2009$ 2009$ % % % yrs. yrs. 

0 202.7 45.91 90.58 136.49 - - - - - -

1 159.6 59.09 72.76 131.85 2.08 10.0 56.9 33.1 2.4 8.1 

2 100.0 112.93 40.69 153.62 -11.07 48.4 40.5 11.1 6.4 7.7 

3 75.0 205.20 30.43 235.63 -93.07 99.9 0.0 0.1 17.2 42.2 

8.4.3.10 Medium Energy, Low Voltage Battery Chargers (Test/Teardown 

Data) 

Figure 8.39 and Figure 8.40 show the distribution of LCC savings and PBPs for each 

th th CSL. In these figures, the ends of the box represent the 25 and 75 percentiles in the 

th th distribution, while the whiskers represent the 5 and 95 percentiles. A percentile represents the 

portion of sampled consumers that fall below a certain threshold. For example, an LCC savings 

value of $1.00 at the 25th percentile means that 25-percent of the sampled consumers will save 

th th $1.00. The bottom portion of the blue 25 percentile box and the top portion of the green 75

th th percentile box represent the 25 and 75 percentile values in the distribution. The figures also 

indicate the median and average value for each CSL. In the case of the PBP distribution, a small 

change in operating cost can occasionally result in a very large PBP. As a result, the upper 

whisker may become disproportionately long, skewing the average PBP value. For this reason, 

the median PBP is a better estimate of the actual PBP. 

8-55 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

CSL 1

Life-Cycle Cost Savings (2009$)

LCC Savings Ranges by Efficiency Level

Box 25% - 75%; Whisker: 5% - 95%

Median

Average

75th Percentile

25th Percentile

Figure 8.39 Medium Energy, Low Voltage Battery Chargers: Distribution of Life-Cycle 

Cost Impacts (Test/Teardown Data)
 

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

CSL 1

Payback Period (years)

PBP Ranges by Efficiency Level

Box 25% - 75%; Whisker: 5% - 95%

Median

Average

75th Percentile

25th Percentile

Figure 8.40 Medium Energy, Low Voltage Battery Chargers: Distribution of PBPs 

(Test/Teardown Data) 

Table 8.4.11 summarizes the LCC and PBP results for the medium energy, low voltage 

BC using the test/teardown data. As mentioned earlier, for some consumers, DOE assigned 

8-56 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

 

products in the base case that are more energy efficient than some of the energy levels under 

consideration. For that reason, the average LCC impacts are not equal to the difference between 

the LCC of a specific energy efficiency level and the LCC of the baseline product. Similarly 

with regard to PBPs shown below, DOE determined the median and average values by excluding 

the percentage of consumers not impacted by a standard at a given efficiency level. The values 

for average operating cost in the table are discounted sums of the annual operating costs over the 

product lifetime. 

For medium energy, low voltage BCs using test/teardown data, CSL 1 is the only 

standards-level above the baseline that DOE had sufficient test/teardown data to evaluate. CSL 1 

has positive average LCC savings ($11.20) and a median PBP of 0.9 years. The majority of 

consumers (56.2-percent) already purchase products at CSL 1, but all consumers impacted by a 

standard set at CSL 1 will experience a net benefit. Consumers are said to have ―no impact‖ if 

the base case forecast product assigned to them has a greater efficiency than the level indicated 

by a standard. 

Table 8.4.11 LCC and PBP Results for Medium Energy, Low Voltage Battery Chargers 

(Test/Teardown Data) 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Avg. 

Operating Avg. 

Wtd. 

Avg. 

Consumers with 

Net No Net 

CSL UEC Price Cost LCC Savings Cost Impact Benefit Median Mean 

kWh 2009$ 2009$ 2009$ 2009$ % % % yrs. yrs. 

0 202.7 45.91 112.90 158.81 - - - - - -

1 159.6 50.64 83.11 133.75 11.20 0.0 56.2 43.8 0.9 0.9 

8.4.3.11 High Energy Battery Chargers (Manufacturer Data) 

Figure 8.41 and Figure 8.42 show the distribution of LCC savings and PBPs for each 

th th CSL. In these figures, the ends of the box represent the 25 and 75 percentiles in the 

th th distribution, while the whiskers represent the 5 and 95 percentiles. A percentile represents the 

portion of sampled consumers that fall below a certain threshold. For example, an LCC savings 

value of $1.00 at the 25th percentile means that 25-percent of the sampled consumers will save 

th th $1.00. The bottom portion of the blue 25 percentile box and the top portion of the green 75

th th percentile box represent the 25 and 75 percentile values in the distribution. The figures also 

indicate the median and average value for each CSL. In the case of the PBP distribution, a small 

change in operating cost can occasionally result in a very large PBP. As a result, the upper 

whisker may become disproportionately long, skewing the average PBP value. For this reason, 

the median PBP is a better estimate of the actual PBP. 

8-57 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

-120.00

-100.00

-80.00

-60.00

-40.00

-20.00

0.00

20.00

CSL 1 CSL 2 CSL 3

Life-Cycle Cost Savings (2009$)

LCC Savings Ranges by Efficiency Level

Box 25% - 75%; Whisker: 5% - 95%

Median

Average

75th Percentile

25th Percentile

Figure 8.41 High Energy Battery Chargers: Distribution of Life-Cycle Cost Impacts 

(Manufacturer Data) 

0.0

5.0

10.0

15.0

20.0

25.0

CSL 1 CSL 2 CSL 3

Payback Period (years)

PBP Ranges by Efficiency Level

Box 25% - 75%; Whisker: 5% - 95%

Median

Average

75th Percentile

25th Percentile

Figure 8.42 High Energy Battery Chargers: Distribution of PBPs (Manufacturer Data) 

Table 8.4.12 summarizes the LCC and PBP results for the high energy BC. As 

mentioned earlier, for some consumers, DOE assigned products in the base case that are more 

energy efficient than some of the energy levels under consideration. For that reason, the average 

8-58 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

LCC impacts are not equal to the difference between the LCC of a specific energy efficiency 

level and the LCC of the baseline product. Similarly with regard to PBPs shown below, DOE 

determined the median and average values by excluding the percentage of consumers not 

impacted by a standard at a given efficiency level. The values for average operating cost in the 

table are discounted sums of the annual operating costs over the product lifetime. 

For high energy BCs, CSL 1 has the highest average LCC savings ($0.10) and a median 

PBP of 5.8 years. Half of all consumers (50.0-percent) are not impacted by a standard set at this 

level, and 20.3-percent of consumers experience a net benefit at this level. Consumers are said 

to have ―no impact‖ if the base case forecast product assigned to them has a greater efficiency 

than the level indicated by a standard. 

Table 8.4.12 LCC and PBP Results for High Energy Battery Chargers (Manufacturer 

Data) 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Avg. 

Operating Avg. 

Wtd. 

Avg. 

Consumers with 

Net No Net 

CSL UEC Price Cost LCC Savings Cost Impact Benefit Median Mean 

kWh 2009$ 2009$ 2009$ 2009$ % % % yrs. yrs. 

0 290.0 195.80 171.85 367.65 - - - - - -

1 250.0 219.13 148.15 367.28 0.10 29.7 50.0 20.3 5.8 5.4 

2 200.0 266.16 118.52 384.68 -12.07 64.2 30.1 5.7 7.8 7.7 

3 150.0 361.77 88.89 450.66 -78.04 100.0 0.0 0.0 12.6 13.6 

8.4.3.12 High Energy Battery Chargers (Test/Teardown Data) 

DOE did not have sufficient test/teardown data to perform an LCC analysis of the low 

energy, inductive representative unit. Section 8.4.3.11 contains LCC and PBP results for this 

representative unit using manufacturer data. 

8.4.3.13 Low Energy, AC Out Battery Chargers (Manufacturer Data) 

Figure 8.43 and Figure 8.44 show the distribution of LCC savings and PBPs for each 

th th CSL. In these figures, the ends of the box represent the 25 and 75 percentiles in the 

th th distribution, while the whiskers represent the 5 and 95 percentiles. A percentile represents the 

portion of sampled consumers that fall below a certain threshold. For example, an LCC savings 

value of $1.00 at the 25th percentile means that 25-percent of the sampled consumers will save 

th th $1.00. The bottom portion of the blue 25 percentile box and the top portion of the green 75

th th percentile box represent the 25 and 75 percentile values in the distribution. The figures also 

indicate the median and average value for each CSL. In the case of the PBP distribution, a small 

change in operating cost can occasionally result in a very large PBP. As a result, the upper 

whisker may become disproportionately long, skewing the average PBP value. For this reason, 

the median PBP is a better estimate of the actual PBP. 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

CSL 1 CSL 2 CSL 3

Life-Cycle Cost Savings (2009$)

LCC Savings Ranges by Efficiency Level

Box 25% - 75%; Whisker: 5% - 95%

Median

Average

75th Percentile

25th Percentile

Figure 8.43 Low Energy, AC Out Battery Chargers: Distribution of Life-Cycle Cost 

Impacts (Manufacturer Data)
 

0.0

0.5

1.0

1.5

2.0

2.5

CSL 1 CSL 2 CSL 3

Payback Period (years)

PBP Ranges by Efficiency Level

Box 25% - 75%; Whisker: 5% - 95%

Median

Average

75th Percentile

25th Percentile

Figure 8.44 Low Energy, AC Out Battery Chargers: Distribution of PBPs (Manufacturer 

Data) 

Table 8.4.13 summarizes the LCC and PBP results for the low energy, AC out BC. As 

mentioned earlier, for some consumers, DOE assigned products in the base case that are more 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

 

 

 

 

energy efficient than some of the energy levels under consideration. For that reason, the average 

LCC impacts are not equal to the difference between the LCC of a specific energy efficiency 

level and the LCC of the baseline product. Similarly with regard to PBPs shown below, DOE 

determined the median and average values by excluding the percentage of consumers not 

impacted by a standard at a given efficiency level. The values for average operating cost in the 

table are discounted sums of the annual operating costs over the product lifetime. 

For low energy, AC out BCs, CSL 3 has the highest average LCC savings ($6.88) and a 

median PBP of 1.5 years. All consumers (100.0-percent) experience a net benefit from a 

standard set at this level. Consumers are said to have ―no impact‖ if the base case forecast 

product assigned to them has a greater efficiency than the level indicated by a standard. 

Table 8.4.13 LCC and PBP Results for Low Energy, AC Out Battery Chargers 

(Manufacturer Data) 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Avg. 

Operating Avg. 

Wtd. 

Avg. 

Consumers with 

Net No Net 

CSL UEC Price Cost LCC Savings Cost Impact Benefit Median Mean 

kWh 2009$ 2009$ 2009$ 2009$ % % % yrs. yrs. 

0 19.6 5.93 11.07 17.00 - - - - - -

1 6.4 7.62 3.60 11.22 5.16 0.0 11.0 89.0 1.3 1.2 

2 4.0 8.08 2.26 10.34 6.04 0.0 0.0 100.0 1.4 1.3 

3 1.5 8.65 0.85 9.50 6.88 0.0 0.0 100.0 1.5 1.5 

8.4.3.14 Low Energy, AC Out Battery Chargers (Test/Teardown Data) 

Figure 8.45 and Figure 8.46 show the distribution of LCC savings and PBPs for each 

th th CSL. In these figures, the ends of the box represent the 25 and 75 percentiles in the 

th th distribution, while the whiskers represent the 5 and 95 percentiles. A percentile represents the 

portion of sampled consumers that fall below a certain threshold. For example, an LCC savings 

value of $1.00 at the 25th percentile means that 25-percent of the sampled consumers will save 

th th $1.00. The bottom portion of the blue 25 percentile box and the top portion of the green 75

th th percentile box represent the 25 and 75 percentile values in the distribution. The figures also 

indicate the median and average value for each CSL. In the case of the PBP distribution, a small 

change in operating cost can occasionally result in a very large PBP. As a result, the upper 

whisker may become disproportionately long, skewing the average PBP value. For this reason, 

the median PBP is a better estimate of the actual PBP. 

The low energy, AC out BC had test/teardown data that indicated a negative-sloping costefficiency curve. As a result, all consumers benefit from standards. This is seen in Figure 8.45, 

where the entire distribution of LCC savings is positive. Similarly, all consumers experience an 

immediate payback, so Figure 8.46 shows the median and average payback period as 0 years 

with no distribution of values around the average. 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

CSL 1

Life-Cycle Cost Savings (2009$)

LCC Savings Ranges by Efficiency Level

Box 25% - 75%; Whisker: 5% - 95%

Median

Average

75th Percentile

25th Percentile

Figure 8.45 Low Energy, AC Out Battery Chargers: Distribution of Life-Cycle Cost 

Impacts (Test/Teardown Data)
 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

CSL 1

Payback Period (years)

PBP Ranges by Efficiency Level

Box 25% - 75%; Whisker: 5% - 95%

Median

Average

75th Percentile

25th Percentile

Figure 8.46 Low Energy, AC Out Battery Chargers: Distribution of PBPs (Test/Teardown 

Data) 

Table 8.4.14 summarizes the LCC and PBP results for the low energy, AC out BC using 

test/teardown data. As mentioned earlier, for some consumers, DOE assigned products in the 

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base case that are more energy efficient than some of the energy levels under consideration. For 

that reason, the average LCC impacts are not equal to the difference between the LCC of a 

specific energy efficiency level and the LCC of the baseline product. Similarly with regard to 

PBPs shown below, DOE determined the median and average values by excluding the 

percentage of consumers not impacted by a standard at a given efficiency level. The values for 

average operating cost in the table are discounted sums of the annual operating costs over the 

product lifetime. 

As mentioned previously, DOE’s cost estimates for low energy, AC out BCs decrease 

from the baseline unit, producing a negative-sloping cost-efficiency curve. As a result, LCC 

savings occur automatically for any user switching from a baseline product. Similarly, all of 

these consumers will experience an instantaneous payback since the purchase price of a product 

at CSL 1 is less than the purchase price at CSL 0. Consumers are said to have ―no impact‖ if the 

base case forecast product assigned to them has a greater efficiency than the level indicated by a 

standard. 

Table 8.4.14 LCC and PBP Results for Low Energy, AC Out Battery Chargers 

(Test/Teardown Data) 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Avg. 

Operating Avg. 

Wtd. 

Avg. 

Consumers with 

Net No Net 

CSL UEC Price Cost LCC Savings Cost Impact Benefit Median Mean 

kWh 2009$ 2009$ 2009$ 2009$ % % % yrs. yrs. 

0 19.6 5.93 11.07 17.00 - - - - - -

1 6.4 4.54 3.60 8.14 7.88 0.0 11.1 88.9 0.0 0.0 

8.4.4 Battery Charger Results (Scaled Product Classes) 

DOE conducted a life-cycle cost analysis on four scaled BC product classes at different 

combinations of battery energy and battery voltage, one for each of the four scaled BC product 

classes: low energy, medium voltage; medium energy, high voltage; DC-DC, <9V input; and 

DC-DC, ≥9V input. As discussed in chapter 5, the cost-efficiency curves for each of the four 

scaled BC product classes were derived by scaling data from the representative units. DOE only 

considered manufacturer-provided data when scaling to these product classes. 

Even though the scaled BC product classes are derived from the representative product 

classes, they still exhibit different LCC results. In general, the scaled BC product classes 

resulted in lower LCC savings than their corresponding representative product classes. This is 

attributable to three main factors. First, many of the scaled product classes have a lighter usage 

profile than the corresponding representative product class, resulting in less opportunity for 

operating cost savings. Second, several of the scaled product classes have lower battery energies 

than their corresponding representative product class, which leads to lower total losses, and thus 

smaller incremental savings from one CSL to another. Finally, some scaled product classes lack 

an EPS whereas their corresponding representative product classes do not. As a result, they do 

not suffer the losses associated with an EPS, and thus have less opportunity for incremental 

operating cost savings. 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

Similar to the representative BC units discussed previously, the MSPs for each efficiency 

level considered in the BC analysis represent the total MSP attributable to a product, not the 

incremental MSP over a baseline level. As such, the average installed prices can be interpreted 

as the total installed cost at each CSL, and the total life-cycle cost is representative of the actual 

cost associated with the product. The LCC savings, PBP calculations, and percentage of 

consumers with a net cost or net benefit are unaffected by the type of MSP used, and thus remain 

accurate. 

8.4.4.1 Base Case LCC Distributions (Manufacturer Data) 

Figure 8.47 through Figure 8.50 show the frequency charts for the base case LCC for the 

four scaled BC product classes using manufacturer data. Since the base case considers the 

different efficiency levels at which consumers currently purchase products, the base case LCC 

distribution is composed of several standards-levels. If all consumers purchased products at CSL 

0 in the base case, then the LCC distribution would be composed entirely of the LCC at CSL 0. 

However, the LCC distribution in the base case shows the LCC results in proportion to how 

many users currently purchase products at each standards-level (CSLs 0 through 3). 

To find the appropriate distribution of LCCs in the base case, the total LCC was 

calculated for each standards-level considered (CSLs 0 through 3). Then these distributions were 

weighted by the market shares for each standards-level in the base case, as discussed in 8.2.10. 

The combined chart shows the aggregated LCC distribution across all CSLs in the base case. 

0%

2%

4%

6%

8%

10%

12%

14%

6.507.809.10

10.40

11.70

13.0014.3015.6016.9018.2019.5020.8022.1023.4024.7026.0027.3028.6029.9031.2032.50

Percent of Consumers (%)

Weighted Total LCC ($)

Total LCC in the Base Case

(weighted by market distribution)

CSL 3

CSL 2

CSL 1

CSL 0

Figure 8.47 Low Energy, Medium Voltage Battery Charger: Base Case LCC Distribution 

(Manufacturer Data) 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

0%

1%

2%

3%

4%

5%

6%

7%

61.1069.1077.2085.2093.20

101.30109.30

117.30

125.30133.40141.40149.40157.50165.50173.50181.50189.60197.60205.60213.70221.70

Percent of Consumers (%)

Weighted Total LCC ($)

Total LCC in the Base Case

(weighted by market distribution)

CSL 3

CSL 2

CSL 1

CSL 0

Figure 8.48 Medium Energy, High Voltage Battery Charger: Base Case LCC Distribution 

(Manufacturer Data) 

0%

5%

10%

15%

20%

25%

30%

1.301.501.701.802.002.102.302.502.602.803.003.103.303.503.603.804.004.10

Percent of Consumers (%)

Weighted Total LCC ($)

Total LCC in the Base Case

(weighted by market distribution)

CSL 3

CSL 2

CSL 1

CSL 0

Figure 8.49 DC-DC, <9V Input Battery Charger: Base Case LCC Distribution 

(Manufacturer Data) 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

0%

5%

10%

15%

20%

25%

30%

35%

3.303.603.904.204.504.805.105.405.706.006.306.606.907.207.50

Percent of Consumers (%)

Weighted Total LCC ($)

Total LCC in the Base Case

(weighted by market distribution)

CSL 3

CSL 2

CSL 1

CSL 0

Figure 8.50 DC-DC, ≥9V Input Battery Charger: Base Case LCC Distribution 

(Manufacturer Data) 

8.4.4.2 Summarized Life-Cycle Cost and Payback Period Results 

Table 8.4.15 through Table 8.4.18 summarizes the LCC and PBP results for the four 

scaled BC product classes using manufacturer data. As mentioned earlier, for some consumers, 

DOE assigned products in the base case that are more energy efficient than some of the energy 

levels under consideration. For that reason, the average LCC impacts are not equal to the 

difference between the LCC of a specific energy efficiency level and the LCC of the baseline 

product. Similarly with regard to PBPs shown below, DOE determined the median and average 

values by excluding the percentage of consumers not impacted by a standard at a given 

efficiency level. The values for average operating cost in the table are discounted sums of the 

annual operating costs over the product lifetime. 

Table 8.4.15 LCC and PBP Results for Low Energy, Medium Voltage Battery Chargers 

(Manufacturer Data) 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Avg. 

Operating Avg. 

Wtd. 

Avg. 

Consumers with 

Net No Net 

CSL UEC Price Cost LCC Savings Cost Impact Benefit Median Mean 

kWh 2009$ 2009$ 2009$ 2009$ % % % yrs. yrs. 

0 10.0 7.38 4.88 12.25 - - - - - -

1 5.4 9.94 2.63 12.57 -0.07 25.6 66.0 8.4 7.5 17.0 

2 1.0 21.42 0.45 21.87 -8.23 83.4 12.0 4.6 32.6 88.3 

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Table 8.4.16 LCC and PBP Results for Medium Energy, High Voltage Battery Chargers 

(Manufacturer Data) 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Avg. 

Operating Avg. 

Wtd. 

Avg. 

Consumers with 

Net No Net 

CSL UEC Price Cost LCC Savings Cost Impact Benefit Median Mean 

kWh 2009$ 2009$ 2009$ 2009$ % % % yrs. yrs. 

0 69.3 45.14 54.91 100.06 - - - - - -

1 41.9 70.52 34.17 104.69 -2.43 41.5 50.0 8.5 8.8 8.9 

2 25.0 130.31 20.37 150.68 -34.75 69.9 30.0 0.1 20.2 28.1 

3 18.0 222.45 14.75 237.20 -121.27 100.0 0.0 0.0 41.5 74.6 

Table 8.4.17 LCC and PBP Results from DC-DC, <9V Input Battery Chargers 

(Manufacturer Data) 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Avg. 

Operating Avg. 

Wtd. 

Avg. 

Consumers with 

Net No Net 

CSL UEC Price Cost LCC Savings Cost Impact Benefit Median Mean 

kWh 2009$ 2009$ 2009$ 2009$ % % % yrs. yrs. 

0 1.5 1.41 0.46 1.87 - - - - - -

1 0.9 2.59 0.27 2.86 -0.39 39.2 60.8 0.0 17.7 23.1 

2 0.8 3.69 0.17 3.86 -1.36 97.2 2.8 0.0 26.3 40.2 

Table 8.4.18 LCC and PBP Results from DC-DC, ≥9V Input Battery Chargers 

(Manufacturer Data) 

Life-Cycle Cost Life-Cycle Cost Savings Payback Period 

Avg. 

Installed 

Avg. 

Operating Avg. 

Wtd. 

Avg. 

Consumers with 

Net No Net 

CSL UEC Price Cost LCC Savings Cost Impact Benefit Median Mean 

kWh 2009$ 2009$ 2009$ 2009$ % % % yrs. yrs. 

0 1.3 1.73 2.36 4.09 - - - - - -

1 0.8 2.61 1.50 4.11 -0.01 30.1 61.1 8.8 20.4 19.0 

2 0.5 5.60 0.89 6.48 -2.32 96.5 2.8 0.7 75.2 72.7 

8.5 DETAILED RESULTS AND SENSITIVITY RUNS 

DOE presents more detailed results and sensitivity runs from the LCC analysis in 

Appendix 8B. These results include electricity price sensitivity scenarios, commercial sector 

sensitivity scenarios, and Monte Carlo probability distributions for high-savings and low-savings 

scenarios. 

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REFERENCES 

i U.S. Department of Energy. Energy Information Administration. Annual Energy Outlook 2010 

Early Release. March, 2010. Washington, D.C. 

http://www.eia.doe.gov/oiaf/aeo/.
 

ii U.S. Department of Energy. Energy Information Administration. Energy Market and 

Economic Impacts of S.2191, The Lieberman-Warner Climate Security Act of 2007. April 2008. 

Washington, D.C.
 

http://www.eia.doe.gov/oiaf/servicerpt/s2191/excel/s2191.xls.
 

iii U.S. Department of Energy. Energy Information Administration. Form EIA-861 Final Data 

File for 2008. March, 2010. Washington, D.C. 

http://www.eia.doe.gov/cneaf/electricity/page/eia861.html. 

iv U.S. Department of Energy. Energy Information Administration. Annual Energy Outlook 2009 

with Projections to 2030. March, 2009. Washington, D.C. 

http://www.eia.doe.gov/oiaf/aeo/index.html. 

v Title 10, Code of Federal Regulations, Part 474, Subpart C – Electric and Hybrid Vehicle 

Research, Development, and Demonstration Program. June 12, 2000. 

http://www.gpo.gov/fdsys/pkg/FR-2000-06-12/html/00-14446.htm. 

vi Bradfield, M. Improving Alternator Efficiency Measurably Reduces Fuel Costs. 2008. Remy
 

International, Inc: Pendleton, IN.
 

vii The Federal Reserve Board, Survey of Consumer Finances 1989, 1992, 1995, 1998, 2001, 

2004, 2007. 

http://www.federalreserve.gov/pubs/oss/oss2/scfindex.html.
 

viii The Federal Reserve Board, Federal Reserve Statistical Release, Selected Interest Rates, 

Historical Data, Instrument: CDs (secondary market), Maturity: 6-month, Frequency: Annual, 

Description: Average rate on 6-month negotiable certificates of deposit (secondary market), 

quoted on an investment basis, 2010.
 

http://www.federalreserve.gov/releases/H15/data.htm.
 

ix The Federal Reserve Board, Federal Reserve Statistical Release, Selected Interest Rates, 

Historical Data, Instrument: State and local bonds, Maturity: 20-year, Frequency: Monthly, 

Description: Bond buyer go 20-bond municipal bond index, 2010. 

http://www.federalreserve.gov/releases/H15/data.htm. 

x The Federal Reserve Board, Federal Reserve Statistical Release, Selected Interest Rates, 

Historical Data, Instrument: Corporate bonds/Moody's Seasoned AAA, Frequency: Annual, 

Description: Moody's yield on seasoned corporate bonds - all industries, AAA, 2010. 

http://www.federalreserve.gov/releases/H15/data.htm. 

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xi Mortgage-X - Mortgage Information Service, Cost of Savings Index (COSI) Index History, 

2010.
 

http://mortgage-x.com/general/indexes/default.asp.
 

xii Damodaran Online Data Page, Historical Returns on Stocks, Bonds and Bills-United States, 

2010. Damodaran.
 

http://pages.stern.nyu.edu/~adamodar.
 

xiii Modigliani, F. and M. Miller. The Cost of Capital, Corporation Finance and the Theory of 

Investment. American Economic Review. 1958. (June): pp. 261-297. 

xiv Ibbotson’s Associates. Stocks, Bonds, Bills, and Inflation, Valuation Edition, 2001 Yearbook. 

2001. 

xv Damodaran, A. Damodaran Online. Current US data. 

http://pages.stern.nyu.edu/~adamodar. 

xvi Executive Office of the President. 2010 Economic Report of the President, U.S. Government 

Printing Office, Washington, D.C., p. 75. 

http://www.whitehouse.gov/sites/default/files/microsites/economic-report-president.pdf. 

xvii Value Line. Value Line Investment Survey. 2010. 

http://www.valueline.com. 

xviii U.S. Office of Management and Budget. Circular No. A-94. Appendix C. 2009. 

http://www.whitehouse.gov/omb/circulars_a094_a94_appx-c/. 

xix U.S. Census Bureau. The 2010 Statistical Abstract. Table 607 – Employment by Industry. 

http://www.census.gov/compendia/statab/2010/tables/10s0607.xls. 

xx U.S. Census Bureau. The 2010 Statistical Abstract. Table 484 – Federal Civilian 

Employment and Annual Payroll by Branch. 

http://www.census.gov/compendia/statab/2010/tables/10s0484.xls. 

xxi U.S. Census Bureau. Government Employment and Payroll. 2008 State and Local 

Government.
 

http://www2.census.gov/govs/apes/08stlall.xls.
 

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CHAPTER 9. SHIPMENTS ANALYSIS 

TABLE OF CONTENTS 

9.1 INTRODUCTION ........................................................................................................... 9-1
 

9.2 BC AND EPS SHIPMENTS IN THE BASE CASE....................................................... 9-1
 

9.2.1 Shipments Forecast .............................................................................................. 9-1
 

9.2.2 Efficiency Forecast .............................................................................................. 9-2
 

9.3 EFFECT OF STANDARDS ON BC AND EPS SHIPMENTS ...................................... 9-3
 

9.3.1 Efficiency of BCs and EPSs ................................................................................ 9-3
 

9.3.2 Price Elasticity of Demand for BCs and EPSs..................................................... 9-4
 

9.3.3 Substitution Away from BCs and EPSs............................................................... 9-4
 

9.4 RESULTS ........................................................................................................................ 9-6
 

9.4.1 External Power Supply Shipments Forecast ........................................................ 9-6
 

9.4.2 Battery Charger Shipments Forecast ................................................................... 9-7
 

LIST OF TABLES 

TABLE 9.1 ROLL-UP MARKET RESPONSE FOR A HYPOTHETICAL BC OR EPS
 

PRODUCT CLASS ..................................................................................................................... 9-4
 

TABLE 9.2 EXTERNAL POWER SUPPLY SHIPMENTS BY PRODUCT CLASS............... 9-6
 

TABLE 9.3 BASE CASE EXTERNAL POWER SUPPLY EFFICIENCY IN 2013................. 9-7
 

TABLE 9.4 BATTERY CHARGER SHIPMENTS BY PRODUCT CLASS ............................ 9-8
 

TABLE 9.5 BASE CASE BATTERY CHARGER EFFICIENCY IN 2013 .............................. 9-9
 

9-i 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

CHAPTER 9. SHIPMENTS ANALYSIS 

9.1 Introduction 

This chapter describes the data and methods that DOE used to generate shipment 

forecasts and base case efficiency distributions for each of the product classes being considered 

in this preliminary analysis of standards for battery chargers and external power supplies. 

Outputs from the shipments analysis are inputs to the life-cycle cost analysis (chapter 8), national 

impact analysis (chapter 10), and manufacturer impact analysis (chapter 12). 

The calculations for shipment forecasts were implemented as part of the National Impact 

Analysis (NIA). These calculations are contained in the NIA Microsoft® Excel workbook that 

can be downloaded from the EERE web site.1 The workbook, entitled “BCEPS Preliminary 

Analysis - NIA.xls” contains a tab for each of the product classes analyzed as part of the 

rulemaking. 

This document is a guide to the inputs and methodology employed in the workbook. 

Section 9.2 presents the methodology for developing a base case shipments forecast. Section 9.3 

discusses the potential impacts of standards on the shipments forecast. The outputs from the 

shipments analysis are shown in Section 9.4. 

9.2 BC and EPS Shipments in the Base Case 

The shipment analysis consists of two outputs: 

A shipments forecast, which calculates the total number of BCs and EPSs shipped each 

year over a 30 year period, beginning in 2013 and ending in 2042. 

An efficiency forecast, which shows the distribution of shipments of BCs and EPSs by 

candidate standard level (CSL), which determines the percentage of shipments affected 

by a standard. 

9.2.1 Shipments Forecast 

To develop its shipments forecast, DOE combined current year (2008) shipments, 

discussed in the market assessment (chapter 3) with a compound annual growth rate for BCs and 

EPSs, discussed in this section. Shipment values were calculated for 30 years, through 2042, the 

last year of the analysis period. Shipments for 2008, 2013 and 2042 are presented in Table 9.2 

(EPSs) and Table 9.4 (BCs). 

As discussed in the market assessment (chapter 3), the variety of product applications that 

employ BCs and EPSs is vast. DOE is aware that this mix of product applications will very likely 

change dramatically over the analysis period. Indeed, most of the end-use products that now 

employ BCs or EPSs were not on the market twenty years ago. Therefore, forecasting the size of 

the market more than twenty years into the future is extremely difficult. 

1 Available for download from the EERE website: 

http://www.eere.energy.gov/buildings/appliance_standards/residential/battery_external.html 

9-1
 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

In its research regarding the market for BCs and EPSs, DOE noted that the market for 

these products has grown tremendously in the past 10 years. Additionally, DOE found that many 

market reports have predicted enormous future growth for the applications that employ BCs and 

EPSs. However, in forecasting the size of the BC and EPS markets over the next 32 years, DOE 

considered the possibility that much of the market growth associated with these products has 

already occurred. For many reports predicting growth of applications that employ BCs or EPSs, 

DOE noted that growth was predicted for new applications, but older applications were generally 

not included. That is, the demand for BCs and EPSs had not grown, but rather the products that 

use BCs and EPSs had transitioned to a new product mix. 

With this in mind, in its forecast DOE took a conservative approach and assumed that 

while the specific applications that use BCs or EPSs will change, the overall number of 

individual units that use BCs or EPSs will grow slowly, with new applications replacing some 

current applications, but with little change in per-capita ownership of BCs or EPSs over time. 

To estimate future market size while assuming no change in the per-capita BC and EPS 

purchase rate, DOE used population growth rate as the compound annual market growth rate. 

DOE feels this growth rate represents a conservative approximation of the expected market 

progression for these products. Population growth rate values were obtained from the U.S. 

Census Bureau 2009 National Projections, which forecast population through 2050. DOE took 

the average annual population growth rate, 0.75 percent, and applied this rate to all BC and EPS 

product classes. 

9.2.2 Efficiency Forecast 

To evaluate the potential impacts of standards, DOE developed a base case efficiency 

forecast, which represents DOE’s estimate of the future state of the market with respect to 

efficiency if energy conservation standards for the units covered under this rulemaking are not 

adopted (or, in the case of Class A EPSs, strengthened). The impact of a standard is then the 

relative improvement in efficiency compared to this forecast. 

DOE’s starting point in developing base case efficiency forecasts was current year 

efficiency distributions, as described in the market assessment (chapter 3). To extrapolate from 

the present day forward to 2013, the first year of the analysis period, DOE looked at recent 

trends in product efficiency and considered what factors might lead BCs and EPSs to become 

more efficient between now and 2013. 

For BCs, DOE found that with the exception of Canada, there were no BC standards 

slated to take effect by 2013. In addition, after reviewing the ENERGY STAR voluntary 

program for battery charging systems, DOE found that as of January 22, 2010, less than 150 

battery charging systems had been qualified.2 Therefore, DOE could find no compelling 

evidence that battery charging systems will improve in efficiency in the short-term. 

2 http://www.energystar.gov/index.cfm?c=battery_chargers.pr_battery_chargers 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

 

For EPSs, DOE found two programs that would influence EPS efficiency in the shortterm. The first is the ENERGY STAR program for EPSs (called “external power adapters”), 

which currently requires that EPSs be at or above CSL 1 in order to qualify. This voluntary 

program is very active, with several thousand qualified products as of January 22, 2010.3 The 

second are the European Union Ecodesign requirements on Energy Using Products, which 

include legislation on EPSs that requires that EPSs sold in the E.U. be at or above CSL 1, 

effective April 2011. Europe currently represents approximately one-third of the global EPS 

market. DOE could find no future program which required efficiency above CSL 1. These 

factors apply to Class A EPSs. With this in mind, DOE estimated that approximately half of the 

Class A EPS market at CSL 0 in 2008 would transition to CSL 1 by 2013. DOE plans to update 

this estimate in the NOPR stage of the analysis. 

In addition, DOE expects that efficiency improvements to Class A EPSs are likely to spill 

over into product classes M1, M2, M3, M4, B1, B2, B3 and B4 because the construction of these 

non-Class A EPSs is very similar to the construction of Class A EPSs. Therefore, DOE assumes 

that EPSs in these product classes will exhibit the same efficiency improvements as Class A 

EPSs between now and 2013. Many of the EPSs in product class X2 are already at CSL 1; DOE 

therefore assumes that there will be little or no further improvements in the efficiency of these 

products in the short term. DOE also assumes no short-term improvement in the efficiency of 

products in product classes X1 and H1, as there are no current or planned standards programs 

that are expected to affect these EPSs. 

In light of the above considerations, DOE developed base case efficiency forecasts in 

which there are modest improvements in EPS efficiency and no improvement in BC efficiency 

between now and 2013. These efficiency forecasts are shown in Table 9.3 for EPSs and Table 

9.5 for BCs. DOE believes that these forecasts provide a reasonable reference point for assessing 

the impact of potential standards. 

DOE next evaluated the likelihood that BCs and EPSs would continue to improve in 

efficiency throughout the analysis period. However, DOE found that although efficiencies might 

improve between now and 2013, no data exist to suggest that BC or EPS efficiencies would 

improve further during the following 30 years in the absence of standards. Therefore, in the 

preliminary analysis DOE forecasts static efficiency distributions for both BCs and EPSs 

throughout the analysis period. 

9.3 Effect of Standards on BC and EPS Shipments 

9.3.1 Efficiency of BCs and EPSs 

In addition to quantifying the projected impact of standards on total shipments, DOE 

must also consider the change in the mix of product efficiencies due to standards. In its 

preliminary analysis, DOE assumed that manufacturers will respond to standards by improving 

those products that do not meet the standards to the standard level, but no higher, while the 

products that were already as or more efficient than the standard remain unaffected. This is 

referred to as a “roll-up” response to standards. 

3 http://www.energystar.gov/index.cfm?c=ext_power_supplies.power_supplies_consumers 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

The mechanics of a roll-up response are detailed in Table 9.1. The “Base Case” gives the 

efficiency distribution with no standard. In the “Standard Set at CSL 1” scenario, all the 

shipments from CSL 0 are rolled up to CSL 1, the level of the standard. The same methodology 

is applied to the other standards cases. 

Table 9.1 Roll-Up Market Response for a Hypothetical BC or EPS Product Class 

Case Percent of Market at Each Efficiency Level 

CSL 0 CSL 1 CSL 2 CSL 3 CSL 4 

Base Case 25% 50% 25% 0% 0% 

Standard Set at CSL 1 0% 75% 25% 0% 0% 

Standard Set at CSL 2 0% 0% 100% 0% 0% 

Standard Set at CSL 3 0% 0% 0% 100% 0% 

Standard Set at CSL 4 0% 0% 0% 0% 100% 

9.3.2 Price Elasticity of Demand for BCs and EPSs 

In other rulemakings, forecasted shipments in the standards case typically deviate from 

the base case. The magnitude of the difference between the standards case and base case 

shipments forecasts depends on the calculated purchase price increase and the operating cost 

savings from the standard. Because the purchase price tends to have a larger impact than 

operating cost on equipment purchase decisions, standards case forecasts typically show 

elasticity of demand, manifested as a change (often a decrease) in shipments relative to the base 

case. However, in the case of BCs and EPSs, DOE expects demand to be fairly inelastic, as the 

incremental cost of more efficient BCs and EPSs is, in most cases, small relative to the total cost 

of the end-use product and is hidden from the consumer as just a portion of the total cost of the 

end-use product. The incremental final product price of Class A EPSs at CSL 4, for example, 

ranges between $0.54 and $6.31. 

Thus, in its preliminary analysis, DOE makes the simplifying assumption that the demand 

for BCs and EPSs is perfectly inelastic; that is, a price increase in the standards case will not lead 

to a decrease in demand for the product. 

9.3.3 Substitution Away from BCs and EPSs 

Another potential market response to the presence of a standard for BCs or EPSs would 

be to substitute a different power source for the BC or EPS. This could reduce BC or EPS 

shipments in the standards case relative to the base case. However, for both BCs and EPSs, the 

extent to which manufacturers choose substitute power sources will be limited by design 

constraints. 

Possible substitutions for BCs include mains power. DOE considers the possibility of 

substitution to be minimal, since such a substitution would remove the primary functionality that 

battery chargers offer, portability. 

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EERE-2008-BT-STD-0005 COMMENT 31
Possible substitutions for EPSs include internal power supplies, batteries, or USB power. 

As with BCs, DOE considers the potential for substitution to be minimal. In most cases, the 

choice of an external power supply over an internal power supply is to minimize the size of the 

application. Use of batteries would not eliminate the usage of an EPS. The last substitute, USB 

power, may have some impact; however, DOE estimates this impact to be limited because USB 

ports are much less common than traditional wall outlets. 

Thus, in its preliminary analysis, DOE assumes that the impact of substitution for BCs 

and EPSs is negligible and, thus, does not attempt to quantify it in the standards case. 

9-5
 

EERE-2008-BT-STD-0005 COMMENT 31
 

9.4 Results 

9.4.1 External Power Supply Shipments Forecast 

In DOE’s forecast, Class A EPS shipments grow from 289 million in 2008 to 372 million 

in 2042. Table 9.2 shows DOE’s shipments forecast for each of the four Class A EPS product 

classes, as well as the eleven non-Class A EPS product classes. 

Table 9.2 External Power Supply Shipments by Product Class 

Output Class 

ID 

2008 

Shipments 

(estimated) 

2013 

Shipments 

(projected) 

2042 

Shipments 

(projected) 

Class A 

AC-DC Basic Voltage A1 206,176,000 214,025,000 265,810,000 

Low Voltage A2 72,195,000 74,943,000 93,076,000 

AC-AC Basic Voltage A3 7,994,000 8,298,000 10,306,000 

Low Voltage A4 2,250,000 2,336,000 2,901,000 

Non-Class A 

Multiple-Voltage 

100 W X1 3,782,000 3,926,000 4,876,000 

≥100 W X2 4,901,000 5,088,000 6,319,000 

High Power >250 W H1 3,000 3,000 4,000 

For Medical 

Devices 

ACDC 

Basic Voltage M1 1,534,000 1,592,000 1,978,000 

Low Voltage M2 25,000 26,000 32,000 

ACAC 

Basic Voltage M3 0 0 0 

Low Voltage M4 0 0 0 

For MotorOperated 

BC 

Applications 

and 

Detachable 

Batteries 

ACDC 

Basic Voltage B1 1,884,000 1,955,718 2,429,000 

Low Voltage B2 275,000 285,000 355,000 

ACAC 

Basic Voltage B3 0 0 0 

Low Voltage B4 0 0 0 

Table 9.3 shows DOE’s assumptions about the efficiency of EPSs in 2013 in the base 

case. The percentages show, for each product class, what fraction of new products sold each year 

are at each efficiency level (CSL). These market shares are assumed to remain constant 

throughout the analysis period, which begins in 2013. 

9-6
 

EERE-2008-BT-STD-0005 COMMENT 31
Table 9.3 Base Case External Power Supply Efficiency in 2013 

Output Class 

ID 

Percentage of Market at Each CSL 

CSL 0 CSL 1 CSL 2 CSL 3 CSL 4 CSL 5 

Class A 

AC-DC 

Basic 

Voltage A1 34 51 12 3 0 -

Low 

Voltage A2 34 51 12 3 0 -

AC-AC 

Basic 

Voltage A3 34 51 12 3 0 -

Low 

Voltage A4 34 51 12 3 0 -

Non-Class A 

Multiple-Voltage 

100 W X1 100 0 0 0 - -

≥100 W X2 5 95 0 0 - -

High Power >250 W H1 60 40 0 0 - -

For Medical 

Devices 

ACDC 

Basic 

Voltage M1 10 29 46 12 3 0 

Low 

Voltage M2 10 29 46 12 3 0 

ACAC 

Basic 

Voltage M3 10 29 46 12 3 0 

Low 

Voltage M4 10 29 46 12 3 0 

For MotorOperated BC 

Applications 

and 

Detachable 

Batteries 

ACDC 

Basic 

Voltage B1 10 29 46 12 3 0 

Low 

Voltage B2 10 29 46 12 3 0 

ACAC 

Basic 

Voltage B3 10 29 46 12 3 0 

Low 

Voltage B4 10 29 46 12 3 0 

9.4.2 Battery Charger Shipments Forecast 

In DOE’s forecast, BC shipments grow from 402 million in 2008 to 519 million in 2042. 

Table 9.4 shows DOE’s shipments forecast for each of the 10 BC product classes. 

9-7 

EERE-2008-BT-STD-0005 COMMENT 31
Table 9.4 Battery Charger Shipments by Product Class 

Battery 

Energy 

Battery 

Voltage 

Class 

ID 

2008 

Shipments 

(estimated) 

2013 

Shipments 

(projected) 

2042 

Shipments 

(projected) 

ACDC 

<100 Wh 

Inductive 

Connection 1 5,354,000 5,558,000 6,903,000 

<4 V 2 206,221,000 214,071,000 265,867,000 

4<10 V 3 23,116,000 23,996,000 29,802,000 

≥10 V 4 69,758,000 72,413,000 89,934,000 

100– 

3000 Wh 

<20 V 5 2,333,000 2,422,000 3,007,000 

≥20 V 6 940,000 976,000 1,212,000 

>3000 Wh 7 214,000 222,000 276,000 

DC-DC <9 V Input 8 71,825,000 74,560,000 92,600,000 

≥9 V Input 9 15,519,000 16,110,000 20,008,000 

AC-AC 

AC Output 

from 

Battery 

10 6,900,000 7,163,000 8,896,000 

9-8
 

EERE-2008-BT-STD-0005 COMMENT 31
Table 9.5 shows DOE’s assumptions about the efficiency of BCs in 2013 in the base 

case. The percentages show, for each product class, what fraction of new products sold each year 

are at each efficiency level (CSL). These market shares are assumed to remain constant 

throughout the analysis period, which begins in 2013. 

Table 9.5 Base Case Battery Charger Efficiency in 2013 

Battery 

Energy 

Battery 

Voltage 

Class 

ID 

Percent of Market at Each CSL 

CSL 0 CSL 1 CSL 2 CSL 3 

ACDC 

<100 

Wh 

Inductive 

Connection 1 75 12.5 12.5 0 

<4 V 2 39 58 3 0 

4<10 V 3 34 54 12 0 

≥10 V 4 19 43 38 0 

100– 

3000 

Wh 

<20 V 5 43 15 40 0 

≥20 V 6 50 20 30 0 

>3000 Wh 7 50 20 30 0 

DC-DC <9 V Input 8 39 58 3 0 

≥9 V Input 9 39 58 3 0 

AC-AC 

AC Output 

from 

Battery 

10 67 22 11 0 

9-9
 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

CHAPTER 10 NATIONAL IMPACT ANALYSIS 

TABLE OF CONTENTS 

10.1 Introduction................................................................................................................. 10-1
 

10.1.1 National Inventory Accounting Model .............................................................. 10-4
 

10.1.2 Calculation of Product Class Lifetime Profiles ................................................. 10-4
 

10.1.3 National Inventory Example .............................................................................. 10-5
 

10.2 National Energy Savings............................................................................................. 10-7
 

10.2.1 Calculating National Energy Savings ................................................................ 10-7
 

10.2.2 Inputs to National Energy Savings Calculation ................................................. 10-7
 

10.2.2.1 Unit Energy Savings ........................................................................................ 10-8
 

10.2.2.2 Site-to-Source Conversion Factors ................................................................ 10-10
 

10.3 Net Present Value ..................................................................................................... 10-11
 

10.3.1 Calculating Net Present Value ......................................................................... 10-11
 

10.3.2 Inputs to Net Present Value Calculation.......................................................... 10-12
 

10.3.2.1 Electricity Prices ............................................................................................ 10-12
 

10.3.2.2 Gasoline Prices............................................................................................... 10-12
 

10.3.2.3 Unit Improvement Costs................................................................................ 10-12
 

10.3.2.4 Discount Rates ............................................................................................... 10-14
 

10.4 Results....................................................................................................................... 10-14
 

10.4.1 National Energy Savings.................................................................................. 10-15
 

10.4.2 Annual Costs and Savings ............................................................................... 10-17
 

10.4.3 Net Present Value ............................................................................................ 10-18
 

LIST OF TABLES 

TABLE 10.1 NATIONAL ANNUAL ENERGY CONSUMPTION OF EXTERNAL POWER 

SUPPLIES SHIPPED IN 2008............................................................................... 10-1
 

TABLE 10.2 NATIONAL ANNUAL ENERGY CONSUMPTION OF BATTERY CHARGERS
 

TABLE 10.3 EXAMPLE PRODUCT CLASS CHARACTERISTICS FOR CALCULATION OF
 

TABLE 10.6. SHIPMENT-WEIGHTED AVERAGE UNIT ENERGY SAVINGS FOR
 

TABLE 10.7. SHIPMENT-WEIGHTED AVERAGE UNIT ENERGY SAVINGS FOR
 

TABLE 10.8. SHIPMENT-WEIGHTED AVERAGE UNIT ENERGY SAVINGS FOR
 

SHIPPED IN 2008.................................................................................................. 10-2
 

LIFETIME PROFILE............................................................................................. 10-4
 

TABLE 10.4 EXAMPLE LIFETIME PROFILE ...................................................................... 10-4
 

TABLE 10.5 EXAMPLE NATIONAL INVENTORY TABLE............................................... 10-5
 

EXTERNAL POWER SUPPLIES (KWH/YR) ..................................................... 10-8
 

BATTERY CHARGERS, MANUFACTURER DATA (KWH/YR) .................... 10-9
 

BATTERY CHARGERS, TEST AND TEARDOWN DATA (KWH/YR) .......... 10-9
 

10-i 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

TABLE 10.9 SHIPMENT-WEIGHTED AVERAGE UNIT IMPROVEMENT COSTS FOR 

EXTERNAL POWER SUPPLIES (2009$) – MANUFACTURER DATA ........ 10-13 

TABLE 10.10 SHIPMENT-WEIGHTED AVERAGE UNIT IMPROVEMENT COSTS FOR 

BATTERY CHARGERS (2009$) – MANUFACTURER DATA....................... 10-13 

TABLE 10.11 SHIPMENT-WEIGHTED AVERAGE UNIT IMPROVEMENT COSTS FOR 

BATTERY CHARGERS (2009$) – TEST AND TEARDOWN DATA............. 10-14 

TABLE 10.12 NATIONAL ENERGY SAVINGS POTENTIAL FROM AMENDED 

STANDARDS FOR EXTERNAL POWER SUPPLIES (TRILLION BTU) ...... 10-15 

TABLE 10.13 NATIONAL ENERGY SAVINGS POTENTIAL FROM NEW STANDARDS 

FOR BATTERY CHARGERS, MANUFACTURER DATA (TRILLION BTU)10-16 

TABLE 10.14 NATIONAL ENERGY SAVINGS POTENTIAL FROM NEW STANDARDS 

FOR BATTERY CHARGERS, TEST AND TEARDOWN DATA (TRILLION 

BTU)..................................................................................................................... 10-17 

TABLE 10.15 NET PRESENT VALUE OF CONSUMER SAVINGS FROM AMENDED 

STANDARDS FOR EXTERNAL POWER SUPPLIES AT A 3 PERCENT 

DISCOUNT RATE, MANUFACTURER DATA (2009$ MILLIONS).............. 10-19 

TABLE 10.16 NET PRESENT VALUE OF CONSUMER SAVINGS FROM AMENDED 

STANDARDS FOR EXTERNAL POWER SUPPLIES AT A 7 PERCENT 

DISCOUNT RATE, MANUFACTURER DATA (2009$ MILLIONS).............. 10-19 

TABLE 10.17 NET PRESENT VALUE OF CONSUMER SAVINGS FROM NEW 

STANDARDS FOR BATTERY CHARGERS AT A 3 PERCENT DISCOUNT 

RATE, MANUFACTURER DATA (2009$ MILLIONS)................................... 10-20 

TABLE 10.18 NET PRESENT VALUE OF CONSUMER SAVINGS FROM NEW 

STANDARDS FOR BATTERY CHARGERS AT A 7 PERCENT DISCOUNT 

RATE, MANUFACTURER DATA (2009$ MILLIONS)................................... 10-21 

TABLE 10.19 NET PRESENT VALUE OF CONSUMER SAVINGS FROM NEW 

STANDARDS FOR BATTERY CHARGERS AT A 3 PERCENT DISCOUNT 

RATE, TEST AND TEARDOWN DATA (2009$ MILLIONS)......................... 10-22 

TABLE 10.20 NET PRESENT VALUE OF CONSUMER SAVINGS FROM NEW 

STANDARDS FOR BATTERY CHARGERS AT A 7 PERCENT DISCOUNT 

RATE, TEST AND TEARDOWN DATA (2009$ MILLIONS)......................... 10-23 

LIST OF FIGURES 

FIGURE 10.1 FLOW CHART SHOWING THE CALCULATION OF NATIONAL ENERGY 

SAVINGS AND NET PRESENT VALUE............................................................ 10-3 

FIGURE 10.2 SITE-TO-SOURCE CONVERSION FACTORS, 2010 TO 2060................... 10-10
 

FIGURE 10.3 REFERENCE CASE ANNUAL UNDISCOUNTED CONSUMER COSTS AND 

SAVINGS FROM A STANDARD AT CSL 1 FOR AC-DC BASIC VOLTAGE 

CLASS A EPSS WITH NAMEPLATE OUTPUT POWER UP TO 10.25 WATTS10-18 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

CHAPTER 10 NATIONAL IMPACT ANALYSIS 

10.1 Introduction 

This chapter describes the methods the U.S. Department of Energy (DOE) used to 

estimate the national consumer impacts of standards for BCs and EPSs. DOE evaluated the 

following impacts: (1) national energy savings (NES) attributable to each possible standard, (2) 

monetary value of those energy savings to consumers of the considered products, (3) increased 

cost of the products because of standards, and (4) net present value (NPV) of total consumer 

costs and savings (the value of energy savings less increased product costs). 

For reference, if current EPS and BC average efficiencies were applied to shipments from 

2008, those units would consume approximately 2.2 billion kWh and 3.4 billion kWh of site 

electricity, respectively, or 24 trillion Btu and 37 trillion Btu of primary energy, respectively, 

each year, as detailed in Table 10.1 and Table 10.2. Values in these tables reflect the inputs used 

in the reference savings case, as described in appendix 8B. 

Table 10.1 National Annual Energy Consumption of External Power Supplies Shipped in 

2008 

Product Class 

Annual Energy Consumption 

Site Energy 

(Million kWh) 

Primary Energy 

(Trillion Btu) 

Percent of Total 

A1: 0-10.25 W 251 3 11% 

A1: 10.25-39 W 930 10 42% 

A1: 39-90 W 582 6 26% 

A1: 90-250 W 186 2 8% 

A2 (DC Output, Low Voltage) 144 2 6% 

A3 (AC Output, Basic Voltage) 113 1 5% 

A4 (AC Output, Low Voltage) 17 0 1% 

All Class A EPSs 2,222 24 100% 

Note: Figures calculated using DOE’s estimates of the efficiency of products in the market in 2009.

Values may not sum to totals due to rounding. 

10-1
 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

Table 10.2 National Annual Energy Consumption of Battery Chargers Shipped in 2008 

Conversion 

Type 

Battery 

Energy 

Battery 

Voltage 

Class 

ID 

Annual Energy Consumption 

Site Energy 

(Million kWh) 

Primary 

Energy 

(Trillion Btu) 

AC-DC 

<100 Wh 

Inductive 

Connection 1 

47 1 1% 

<4 V 2 1,539 17 45% 

4<10 V 3 148 2 4% 

≥10 V 4 991 11 29% 

100–

3000 Wh 

<20 V 5 359 4 11% 

≥20 V 6 48 1 1% 

>3000 Wh 7 55 1 2% 

DC-DC <9 V Input 8 80 1 2% 

≥9 V Input 9 15 0.3 <1% 

AC-AC 

AC Output 

from 

Battery 

10 

125 1 4% 

All Battery Chargers 3,408 37 100% 

DOE determined both the NES and NPV for each candidate standard level (CSLs) for 

BCs and EPSs. These calculations are described in detail as follows: 

National Inventory, discussed in section 10.1.1, details the methodology for 

calculating the number of units in use in a given year that are subject to a standard. 

NES, discussed in section 10.2, combines the average change in unit energy 

consumption (UEC) due to a standard (unit energy savings) with the national 

inventory to obtain the aggregate energy savings generated by a standard. 

NPV, discussed in Section 10.3, compares the present value (in 2009$) of the NES 

with the present value (in 2009$) of the national improvement costs associated with a 

standard. National improvement cost combines the average change in unit cost (unit 

improvement cost) with the number of units shipped in a given year to obtain the 

aggregate incremental costs paid by consumers due to a standard. 

The national impact analysis (NIA) is depicted graphically in Figure 10.1. Results for 

BCs and Class A EPSs are presented in section 10.4. NIA results for non-Class A EPSs will be 

calculated in the next (NOPR) stage of the rulemaking. Preliminary NIA results for non-Class A 

EPS product classes were presented in DOE’s determination for non-Class A External Power 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

Supplies.a However, these results were calculated using different methodologies, and thus should 

not be compared with the NIA results presented here for Class A EPSs. 

All calculations are contained in a Microsoft Excel workbook, which can be downloaded 

from the EERE website.b The shipments analysis (see chapter 9) provides a detailed description 

of the model DOE used to forecast future purchases of the considered products. 

Calculation of Net Present Value

Electricity Price

National Energy 

Savings (kWh)

National 

Improvement Costs

Unit Energy Savings

National Inventory

Unit Improvement 

Cost

National Energy 

Savings ($)

Discount Rate Net Present Value

Figure 10.1 Flow Chart Showing the Calculation of National Energy Savings and Net 

Present Value 

While the life-cycle cost analysis weighs the costs and savings associated with standards 

for a set of representative units, the NIA considers the costs and savings associated with 

standards for all products, including those in the “scaled” product classes. For these scaled 

product classes, most inputs to the NIA could be obtained in the same manner as for the 

representative product classes. However, cost data were not available for the scaled product 

classes, as they were not directly analyzed in the engineering analysis. Therefore, as is done in 

other rulemakings, DOE extrapolated from its knowledge of costs for the representative product 

classes to the scaled product classes. In the preliminary analysis, DOE applied costs from the 

EPS representative units to product classes A2, A3 and A4 as appropriate given observed 

similarities between the products in these classes. Costs from the 2.5 W EPS representative unit 

were applied to product classes A2 and A4, and costs from the 18 W EPS representative unit 

were applied to product class A3. Costs for BC product classes 3, 6, 8, and 9 were derived from 

cost data for the representative product classes as described in chapter 5. 

a See 

http://www1.eere.energy.gov/buildings/appliance_standards/residential/battery_external_det_2008_non_class_a.htm 

b See http://www.eere.energy.gov/buildings/appliance_standards/residential/battery_external.html 

10-3
 

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EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

10.1.1 National Inventory Accounting Model 

DOE used a national inventory model to represent the number of BC and EPS units in use 

during a given year that would be subject to a standard. 

Unlike many other rulemakings, where an installed base of products governs shipments 

(via retirement/replacement of the existing stock and installation of new stock in new homes), for 

BCs and EPSs shipments govern the national inventory. DOE chose this method for calculating 

national inventory based on two factors that distinguish BCs and EPSs. First, the size of the 

existing inventory of products in use is not fully known. Second, DOE cannot assume that all 

retired products are immediately replaced, so the number of shipments in a given year cannot be 

based on the number of existing products retired in that year. 

Initially there are no units in the national inventory. Each year after a standard takes 

effect, new units are added to the inventory and those units that have reached the end of their 

lives are removed from the inventory. DOE used two inputs to calculate the national inventory: 

shipments forecasts (see chapter 9) and product class lifetime profiles, which are derived by 

combining base-year shipments by application with application lifetimes (see chapter 3). 

10.1.2 Calculation of Product Class Lifetime Profiles 

For the preliminary analysis, DOE calculated product class lifetime profiles using the 

percentage of shipments of applications within a given product class, and the lifetimes of those 

applications. These values were combined to estimate the percentage of units remaining in use 

for each year following the initial year in which those units were shipped. 

As an example, consider a product class X with four associated applications: A, B, C, 

and D. Base year shipments and lifetimes for these applications are shown in Table 10.3. 

Table 10.3 Example Product Class Characteristics for Calculation of Lifetime Profile 

Application Base Year Shipments 

(Units) 

Percentage of Base Year 

Shipments 

(%) 

Lifetime 

(Years) 

A 100,000 53% 4 

B 25,000 13% 3 

C 15,000 8% 2 

D 50,000 26% 5 

Based on these application-specific values, product class X’s lifetime profile would be as 

shown in Table 10.4. 

Table 10.4 Example Lifetime Profile 

Percentage of Units Remaining in Use 

2013 

(Shipment 

2014 2015 2016 2017 2018 

10-4
 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

Year) 

100% 100% 92% 79% 26% 0% 

In 2013, 100% of units are shipped and put into use. 

At the end of 2013, after 1 year of use, none of the products have reached their lifetime, 

so 0% of the units are retired, leaving 100% of the initial shipment remaining in use in 

2014. 

At the end of 2014, after 2 years of use, units for product C, representing 8% of the total 

initial shipment, reach their lifetime and are retired, leaving 92% of the initial shipment 

remaining in use in 2015. 

At the end of 2015, after 3 years of use, units for product B, representing 13% of the total 

initial shipment, reach their lifetime and are retired, leaving 79% of the initial shipment 

remaining in use in 2016. 

At the end of 2016, after 4 years of use, units for product A, representing 53% of the total 

initial shipment, reach their lifetime and are retired, leaving 26% of the initial shipment 

remaining in use in 2017. 

At the end of 2017, after 5 years of use, units for product D, representing 26% of the total 

initial shipment, reach their lifetime and are retired, leaving 0% of the initial shipment 

remaining in use in 2018. 

Since no units remain in use in 2018, the lifetime profile calculation is complete. 

10.1.3 National Inventory Example 

Table 10.5 gives an example showing how the national inventory is tracked over the first 

seven years of the analysis period. This example uses as inputs: 

Shipments of 100 units in 2013
 

Market growth of 5 percent per year
 

The lifetime profile shown in Table 10.4.
 

Table 10.5 Example National Inventory Table 

Vintage Year of Analysis 

2013 2014 2015 2016 2017 2018 2019 

2013 100 100 92 79 26 - -

2014 - 105 105 97 83 27 

2015 - - 110 110 101 87 29 

2016 - - - 116 116 107 92 

2017 - - - - 122 122 112 

2018 - - - - - 128 128 

2019 - - - - - - 134 

National 

Inventory 

100 205 307 402 446 468 492 

10-5
 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

In 2013: 

In 2014: 

100 units are shipped (vintage 2013) and are added to the national inventory. 

The total national inventory is 100 units. 

0 units from vintage 2013 are retired, leaving 100 units.
 

105 new units are shipped (vintage 2014), reflecting a 5% increase over the previous
 

year. 

The total national inventory is 205 units. 

In 2015: 

8 units (8%) from vintage 2013 are retired, leaving 92 units.
 

0 units from vintage 2014 are retired, leaving 105 units.
 

110 units are shipped (vintage 2015).
 

The total national inventory is 307 units.
 

In 2016: 

13 units (13%) from vintage 2013 are retired, leaving 79 units.
 

8 units (8%) from vintage 2014 are retired, leaving 97 units.
 

0 units from vintage 2015 are retired, leaving 110 units.
 

116 units are shipped (vintage 2016).
 

The total national inventory is 402 units.
 

In 2017: 

53 units (53%) from vintage 2013 are retired, leaving 26 units.
 

14 units (13%) from vintage 2014 are retired, leaving 83 units.
 

9 units (8%) from vintage 2015 are retired, leaving 101 units.
 

0 units from vintage 2016 are retired, leaving 116 units.
 

122 units are shipped (vintage 2017).
 

The total national inventory is 446 units.
 

In 2018: 

26 units (26%) from vintage 2013 are retired, leaving 0 units.
 

56 units (53%) from vintage 2014 are retired, leaving 27 units.
 

14 units (13%) from vintage 2015 are retired, leaving 87 units.
 

9 units (8%) from vintage 2016 are retired, leaving 107 units.
 

0 units from vintage 2017 are retired, leaving 122 units.
 

128 units are shipped (vintage 2018).
 

The total national inventory is 468 units.
 

In 2019: 

27 units (26%) from vintage 2014 are retired, leaving 0 units. 

58 units (53%) from vintage 2015 are retired, leaving 29 units. 

15 units (13%) from vintage 2016 are retired, leaving 92 units. 

10-6
 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

10 units (8%) from vintage 2017 are retired, leaving 112 units.
 

0 units from vintage 2018 are retired, leaving 128 units.
 

134 units are shipped (vintage 2019).
 

The total national inventory is 492 units.
 

10.2 National Energy Savings 

DOE calculated the NES associated with a standard at each CSL for BCs and EPSs. The 

calculation of NES, which represents the total energy savings for a product class over the entire 

analysis period, encompasses three steps: 

1)	 The annual unit energy savings (UES) associated with a CSL is calculated as the 

difference in energy consumption between an average unit in the absence of standards 

(base case) and an average unit with a standard set at that CSL. 

2) The UES is then multiplied by the national inventory for a given year for that product 

class to obtain annual NES for that year. 

3) Annual NES is then calculated for each year of the analysis period and summed. 

10.2.1 Calculating National Energy Savings 

For a given product class and CSL, DOE first calculated annual UES (in kWh/year) as 

the difference in annual energy consumption between an average unit in the base case (UECBase) 

and an average unit in the standards case (UECCSL). 

Equation 10.1 UESCSL = UECBase - UECCSL 

DOE then calculated the NES in a given year (NESYear-kWh) by multiplying the national 

inventory in that year (NationalInventoryYear) by the UESCSL. The calculation of NESYear-kWh is 

represented by the following equation: 

Equation 10.2 NESYear-kWh = NationalInventoryYear × UESCSL 

DOE then calculated NESkWh for the entire analysis period by repeating the above 

NESYear for each year, and then summing the results. The calculation is represented by the 

following equation: 

Equation 10.3 NESkWh = ΣNESYear-kWh 

10.2.2 Inputs to National Energy Savings Calculation 

There are three inputs to the NES calculation: 

o	 National inventory (explained in section 10.1.1) 

o	 Unit energy savings (explained in section 10.2.2.1) 

o	 Site-to-source conversion factor (explained in section 10.2.2.2) 

10-7
 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

10.2.2.1 Unit Energy Savings 

DOE used the efficiency distributions for the base case presented in chapter 9 along with 

the annual UEC values presented in chapter 7 to estimate shipment-weighted average UEC under 

the base and standards cases, which were then compared against one another to give UES values 

for each CSL. 

As explained in chapter 9, DOE assumed that energy efficiency would not improve after 

2013 in the base case. Therefore, UEC values do not vary over time, and thus UES values do not 

vary over time. In addition, DOE assumed that manufacturers would respond to a standard by 

improving the efficiency of underperforming products but not those that already meet or exceed 

the standard, as discussed in chapter 9. 

The average annual UES for each product class and CSL is shown in Table 10.6 for EPSs 

and in Table 10.7 and Table 10.8 for BCs. Values are reported for all Class A EPSs, with product 

class A1 broken out into four segments by nameplate output power, corresponding to the four 

representative units examined in the engineering analysis. Only reference case values are shown 

here. 

Table 10.6. Shipment-Weighted Average Unit Energy Savings for External Power 

Supplies (kWh/yr) 

Product Class 

Standard Level Selected 

CSL 1 CSL 2 CSL 3 CSL 4 

A1: 0-10.25 W 0.46 0.91 1.16 1.27 

A1: 10.25-39 W 1.24 3.01 4.74 6.06 

A1: 39-90 W 0.47 1.87 3.18 5.11 

A1: 90-250 W 0.88 3.12 3.73 7.84 

A2 (DC Output, Low Voltage) 0.30 0.74 0.89 1.02 

A3 (AC Output, Basic Voltage) 1.27 3.07 4.85 6.19 

A4 (AC Output, Low Voltage) 1.03 1.69 2.27 2.37 

All Class A EPSs 0.64 1.67 2.49 3.40 

10-8
 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

Table 10.7. Shipment-Weighted Average Unit Energy Savings for Battery Chargers, 

Manufacturer Data (kWh/yr) 

Conversion 

Type 

Battery 

Energy 

Battery 

Voltage 

Class 

ID 

Standard Level Selected 

CSL 1 CSL 2 CSL 3 

AC-DC 

<100 Wh 

Inductive 

Connection 1 2.25 5.31 7.31 

<4 V 2 1.57 6.31 N/A 

4<10 V 3 1.57 5.47 N/A 

≥10 V 4 5.40 8.09 N/A 

100–

3000 Wh 

<20 V 5 19.06 53.92 78.97 

≥20 V 6 13.69 25.55 32.56 

>3000 Wh 7 20.00 55.00 105.00 

DC-DC <9 V Input 8 0.24 0.56 N/A 

≥9 V Input 9 0.18 0.49 N/A 

AC-AC 

AC Output 

from 

Battery 

10 11.76 14.13 16.63 

Table 10.8. Shipment-Weighted Average Unit Energy Savings for Battery Chargers, Test 

and Teardown Data (kWh/yr) 

Conversion 

Type 

Battery 

Energy 

Battery 

Voltage 

Class 

ID 

Standard Level Selected 

CSL 1 CSL 2 CSL 3 

AC-DC 

<100 Wh 

Inductive 

Connection 1 No Data 

<4 V 2 N/A 6.09* N/A 

4<10 V 3 No Data 

≥10 V 4 5.41 8.11 N/A 

100–

3000 Wh 

<20 V 5 23.15 N/A N/A 

≥20 V 6 No Data 

>3000 Wh 7 No Data 

DC-DC <9 V Input 8 No Data 

≥9 V Input 9 No Data 

AC-AC 

AC Output 

from 

Battery 

10 11.76 N/A N/A 

*Savings for BC product class 2 are relative to CSL 1 because CSL 0 is not defined for this product class in the test 

and teardown data. 

10-9 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

10.2.2.2 Site-to-Source Conversion Factors 

In determining national annual energy consumption, DOE initially calculated the annual 

energy consumption and savings at the site in kWh. It then converted site energy savings to 

primary (source) energy savings. For all product classes except BC product class 9, this 

conversion was achieved by applying a site-to-source conversion factor to account for losses 

associated with the generation, transmission, and distribution of electricity. 

For mains electricity DOE used annual site-to-source conversion factors based on EIA’s 

Annual Energy Outlook 2010 (AEO 2010), Table 4. Residential Sector Key Indicators and 

Consumption.

1 Figure 10.2 shows the site-to-source conversion factors for each year from 2010 

through 2060. Factors for each year from 2010 to 2035 were calculated by dividing the sum of 

Delivered Energy [Electricity] and Electricity Related Losses by Delivered Energy [Electricity]. 

The site-to-source conversion factor given by AEO 2010 for 2013 is 3.169. The factor declines 

gradually from 2013 to 2035 as the power system is expected to become more energy efficient 

during that period. The site-to-source conversion factor is held constant at the 2035 value in later 

years, which are beyond the time horizon of the AEO 2010 forecast. 

Figure 10.2 Site-to-Source Conversion Factors, 2010 to 2060 

Site-to-source conversion for BCs powered by automotive power sources (BC product 

class 9) differs from other product classes, as the energy source for these products is gasoline, 

which is then converted into electric power by the engine. Prior research uncovered has 

determined that the typical efficiency in converting gasoline to electric power is 21 percent.2 In 

addition, DOE previously determined that petroleum refining and distribution efficiency is 83 

percent. 3 Multiplying these two efficiencies together yields a net efficiency of 17.43 percent, 

which is equivalent to a site-to-source conversion factor of 5.74. DOE applied this conversion 

factor over the entire analysis period. DOE assumed that power for BCs in product class 9 is 

10-10
 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

provided directly by the engine, and so did not include any efficiency losses from the automotive 

battery. 

10.3 Net Present Value 

DOE calculated the NPV of the increased product costs and reduced operating costs 

associated with a standard at each CSL for BCs and EPSs. The calculation of NPV, which 

represents the present value of the difference between consumer savings and costs over the entire 

analysis period, encompasses six steps: 

1.	 The NESYear-kWh site electricity savings values are converted to energy cost savings by 

multiplying by forecast electricity rates, with each year discounted to present value. 

2.	 The unit improvement costs (UIC) associated with a CSL is calculated as the difference 

in cost between an average unit in the base case and an average unit in the standards case. 

3.	 The UIC is then multiplied by the shipments for a given shipment year for that product 

class to obtain an annual National Improvement Cost (NICYear). 

4.	 The calculation of the annual NICYear is then repeated for each year of the shipment 

forecast period, with each year discounted to present value. 

5.	 Present value NICYear is then subtracted from present value NESYear-$ for each year of the 

analysis period, yielding net present value for each year (NPVYear). 

6.	 NPVYear values are then summed to yield total NPV. 

10.3.1 Calculating Net Present Value 

DOE first converted site national energy savings for a given year (NESYear-kWh) to present 

value energy cost savings (in 2009$) by first multiplying by the projected fuel price for that year 

(FuelPriceYear) and then multiplying the product by a discount factor for that year (DFYear), as 

described by the following equation. This process was repeated for each year. 

Equation 10.4 NESYear-$ = NESYear-kWh × FuelPriceYear × DFYear 

Next for a given product class and CSL, DOE first calculated UIC as the difference in 

unit cost between an average unit in the base case (AvgUnitCostBase) and an average unit in the 

standards case (AvgUnitCostCSL). 

Equation 10.5 UICCSL = AvgUnitCostBase − AvgUnitCostCSL 

DOE then calculated the present value of NIC (in 2009$) for a given year (NICYear) by 

multiplying the shipments for a given year for the product class (ShipmentsYear) by the UICCSL of 

that product class, and multiplying the product by a discount factor for that year (DFYear). The 

calculation of NICYear is represented by the following equation. This process was repeated for 

each year. 

Equation 10.6 NICYear = ShipmentsYear × UICCSL × DFYear 

DOE calculated NPV for each year as the difference between NES$-Year and NICYear, with 

positive values indicating cost effectiveness: 

10-11
 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

 

 

 

 

 

 

 

Equation 10.7 NPVYear = NES$-Year - NICYear 

Finally, DOE summed NPVYear values over all years to obtain NPV. 

Equation 10.8 NPV = ∑NPVYear 

10.3.2 Inputs to Net Present Value Calculation 

There are six inputs to the NPV calculation: 

Shipments (explained in chapter 9)
 

National energy savings (explained in section 10.2)
 

Electricity prices (explained in section 10.3.2.1)
 

Gasoline prices (explained in section 10.3.2.2)
 

Unit improvement costs (explained in section 10.3.2.3)
 

Discount rates (explained in section 10.3.2.4)
 

10.3.2.1 Electricity Prices 

DOE used the methodology described in chapter 8 for forecasting electricity prices for 

residential and commercial consumers. In the preliminary analysis, DOE assumed all energy 

consumption and savings would take place in the residential sector and used a trend function to 

extend the electricity price forecast used in the LCC analysis from 2030 until the end of the 

analysis period. 

10.3.2.2 Gasoline Prices 

For BCs powered by automotive power sources (BC product class 9), DOE calculated 

consumer energy cost savings using gasoline prices rather than electricity prices. To assign a 

price to the energy consumed by these BCs, DOE first converted the electricity consumed by the 

BC (in kWh) into the equivalent quantity of gasoline (in gallons) by using an energy equivalence 

conversion factor of 33.705 kWh per gallon of gasoline.3 DOE then divided the resulting gallons 

by average automobile energy conversion efficiency (21 percent, from section 10.2.2.2). To 

convert these gasoline savings into consumer cost savings, DOE multiplied the resulting gallons 

of gasoline by the gasoline price. 

DOE used the gasoline price forecast in AEO 2010, and converted prices from 2008$ to 

2009$. As with the electricity price forecasts, DOE used an Excel trend function to extend the 

gasoline price forecast from 2030 to 2060. 

10.3.2.3 Unit Improvement Costs 

DOE used the efficiency distributions for the base case presented in chapter 9, the 

manufacturer selling prices presented in chapter 5, and markups and sales tax from chapter 6 to 

calculate the UIC in each standards case. Manufacturers are assumed to respond to a standard by 

improving the efficiency of underperforming products but not those that already meet or exceed 

the standard, as discussed in chapter 9. Average unit improvement costs in each scenario are 

shown in Table 10.9 for EPSs and Table 10.10 and Table 10.11 for BCs. 

10-12
 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

In the preliminary analysis, DOE applied costs from the EPS representative units to 

product classes A2, A3 and A4 as appropriate given observed similarities between the products 

in these classes. Costs from the 2.5 W EPS representative unit were applied to product classes 

A2 and A4, and costs from the 18 W EPS representative unit were applied to product class A3. 

Similarly, DOE derived cost estimates for scaled BC product classes 3, 6, 8, and 9 from its cost 

estimates for the representative product classes. These calculations are discussed in chapter 5. 

Table 10.9 Shipment-Weighted Average Unit Improvement Costs for External Power 

Supplies (2009$) – Manufacturer Data 

Product Class 

Standard Level Selected 

CSL 1 CSL 2 CSL 3 CSL 4 

A1: 0-10.25 W $0.02 $0.26 $0.38 $0.54 

A1: 10.25-39 W $0.15 $0.28 $0.77 $1.40 

A1: 39-90 W $0.12 $0.69 $1.91 $3.81 

A1: 90-250 W $0.31 $0.99 $1.23 $6.31 

A2 (DC Output, Low Voltage) $0.02 $0.27 $0.40 $0.56 

A3 (AC Output, Basic Voltage) $0.15 $0.28 $0.78 $1.40 

A4 (AC Output, Low Voltage) $0.02 $0.25 $0.36 $0.51 

All Class A EPSs $0.08 $0.37 $0.80 $1.57 

Table 10.10 Shipment-Weighted Average Unit Improvement Costs for Battery Chargers 

(2009$) – Manufacturer Data 

Conversion 

Type 

Battery 

Energy Battery Voltage Class ID 

Standard Level Selected 

CSL 1 CSL 2 CSL 3 

AC-DC 

<100 Wh 

Inductive 

Connection 1 $0.16 $0.43 $0.64 

<4 V 2 $0.28 $15.81 N/A 

4<10 V 3 $0.87 $10.98 N/A 

≥10 V 4 $1.51 $4.27 N/A 

100–3000 

Wh 

<20 V 5 $5.72 $37.89 $130.21 

≥20 V 6 $12.69 $54.57 $146.76 

>3000 Wh 7 $11.67 $44.62 $140.28 

DC-DC 

<9 V Input 8 $0.46 $1.54 N/A 

≥9 V Input 9 $0.35 $3.25 N/A 

AC-AC 

AC Output 

from Battery 10 $1.50 $1.96 $2.53 

10-13
 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

Table 10.11 Shipment-Weighted Average Unit Improvement Costs for Battery Chargers 

(2009$) – Test and Teardown Data 

Conversion 

Type 

Battery 

Energy Battery Voltage Class ID 

Standard Level Selected 

CSL 1 CSL 2 CSL 3 

AC-DC 

<100 Wh 

Inductive 

Connection 1 No Data 

<4 V 2 N/A $2.93* N/A 

4<10 V 3 No Data 

≥10 V 4 $0.78 $1.38 N/A 

100–3000 

Wh 

<20 V 5 $2.06 N/A N/A 

≥20 V 6 No Data 

>3000 Wh 7 No Data 

DC-DC <9 V Input 8 No Data 

≥9 V Input 9 No Data 

AC-AC AC Output 

from Battery 10 -$0.65 N/A N/A 

*Costs for BC product class 2 are relative to CSL 1 because CSL 0 is not defined for this product class in the test 

and teardown data. 

Note: In the NIA workbook, manufacturer selling prices (MSPs) are presented for both 

EPSs and BCs. While prices for EPSs are marginal (adjusted so that the price of a unit at CSL 0 

is zero), and prices for BCs are absolute, the NIA calculation of UIC employs the same 

methodology for both products. 

10.3.2.4 Discount Rates 

To calculate NPV, DOE discounted future consumer costs and savings to the present day 

(2010) using discount rates of 3 percent and 7 percent. These discount rates are specified by the 

U.S. Office of Management and Budget (OMB) (OMB, Circular A-4: Regulatory Analysis, 

2003). 

10.4 Results 

DOE estimated NES and NPV for BC standards separately from EPS standards. Results 

for the two products should not be added to one another because many BCs incorporate an EPS. 

One way to improve the efficiency of these BCs is to improve the efficiency of the EPS part. The 

resulting savings are counted in both the BC analysis and in the separate EPS analysis. Thus, due 

to this overlap, combining BC and EPS NES (or NPV) estimates would overstate savings 

resulting from improving BCs and EPSs. 

10-14
 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

10.4.1 National Energy Savings 

DOE’s preliminary analysis finds that new standards for BCs and amended standards for 

EPSs could produce cumulative energy savings over the period of analysis of as much as 

3.5 quadrillion Btu (quads) and 1.5 quads, respectively, in the case where energy savings are 

maximized. In the case where consumer benefits are maximized, new standards for BCs and 

amended standards for EPSs could produce cumulative energy savings over the period of 

analysis of 1.4 quadrillion Btu (quads) and 1.0 quads, respectively. 

Results for each standards case are shown in Table 10.12 for EPSs, and Table 10.13 and 

Table 10.14 for BCs. In each cell, results from the reference savings case are shown in the top of 

the cell, with results from the low and high savings cases shown in parentheses in the bottom of 

the cell. Low and high results are only shown for product classes for which energy savings vary 

between scenarios. 

Table 10.12 National Energy Savings Potential from Amended Standards for External 

Power Supplies (Trillion Btu) 

Product Class 

Standard Level Selected 

CSL 1 CSL 2 CSL 3 CSL 4 

A1: 0-10.25 W 57 

(46 to 58) 

114 

(99 to 142) 

144 

(127 to 180) 

158 

(140 to 202) 

A1: 10.25-39 W 132 

(119 to 145) 

319 

(287 to 352) 

504 

(453 to 555) 

643 

(578 to 710) 

A1: 39-90 W 34 

(31 to 43) 

137 

(128 to 167) 

232 

(217 to 286) 

374 

(345 to 466) 

A1: 90-250 W 10 

(9 to 15) 

35 

(32 to 54) 

42 

(38 to 64) 

88 

(78 to 137) 

A2 (DC Output, Low 

Voltage) 32 81 96 111 

A3 (AC Output, Basic 

Voltage) 26 64 101 128 

A4 (AC Output, Low 

Voltage) 4 7 9 10 

All Class A EPSs 296 

(267 to 325) 

756 

(697 to 866) 

1128 

(1041 to 1291) 

1512 

(1389 to 1763) 

10-15
 

EERE-2008-BT-STD-0005 COMMENT 31
Table 10.13 National Energy Savings Potential from New Standards for Battery 

Chargers, Manufacturer Data (Trillion Btu) 

Conversion 

Type 

Battery 

Energy 

Battery 

Voltage 

Class 

ID 

Standard Level Selected 

CSL 1 CSL 2 CSL 3 

AC-DC 

<100 Wh 

Inductive 

Connection 1 22 52 71 

<4 V 2 397 

(338 to 422) 

1596 

(1276 to 1792) N/A 

4<10 V 3 59 206 N/A 

≥10 V 4 543 

(465 to 767) 

813 

(694 to 1149) N/A 

100–

3000 Wh 

<20 V 5 88 

(19 to 88) 

250 

(109 to 250) 

366 

(136 to 366) 

≥20 V 6 41 76 97 

>3000 Wh 7 9 

(5 to 16) 

26 

(12 to 43) 

49 

(24 to 81) 

DC-DC <9 V Input 8 21 50 N/A 

≥9 V Input 9 10 26 N/A 

AC-AC 

AC Output 

from 

Battery 

10 177 213 250 

10-16
 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

Table 10.14 National Energy Savings Potential from New Standards for Battery 

Chargers, Test and Teardown Data (Trillion Btu) 

Conversion 

Type 

Battery 

Energy 

Battery 

Voltage 

Class 

ID 

Standard Level Selected 

CSL 1 CSL 2 CSL 3 

AC-DC 

<100 Wh 

Inductive 

Connection 1 No Data 

<4 V 2 N/A 1541* 

(1273 to 1733) N/A 

4<10 V 3 No Data 

≥10 V 4 544 

(478 to 773) 

815 

(722 to 1164) N/A 

100–

3000 Wh 

<20 V 5 107 

(63 to 107) N/A N/A 

≥20 V 6 No Data 

>3000 Wh 7 No Data 

DC-DC <9 V Input 8 No Data 

≥9 V Input 9 No Data 

AC-AC 

AC Output 

from 

Battery 

10 177 N/A N/A 

*Savings for BC product class 2 are relative to CSL 1 because CSL 0 is not defined for this product class in the test 

and teardown data. 

10.4.2 Annual Costs and Savings 

To illustrate the basic inputs to the NPV calculations, Figure 10.3 presents the 

undiscounted NIC and NES at CSL 1 for AC-DC basic voltage Class A EPSs with nameplate 

output power up to 10.25 watts. The figure also shows the net consumer savings, which is the 

difference between the NIC and NES for each year. DOE can create figures like this one for each 

standards case. 

10-17
 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

 

 

 

 

Figure 10.3 Reference Case Annual Undiscounted Consumer Costs and Savings from a 

Standard at CSL 1 for AC-DC Basic Voltage Class A EPSs with Nameplate Output 

Power up to 10.25 Watts 

10.4.3 Net Present Value 

The tables in this section present DOE’s preliminary estimates of the national NPV of

total consumer costs and savings expected to result from standards at specific efficiency levels 

for BCs and EPSs. 

DOE’s preliminary analysis finds that new standards for BCs and amended standards for 

EPSs could yield net consumer savings over the period of analysis of $4.5 billion and $3.4 

billion, respectively, in the case where consumer benefits are maximized. In the case where 

energy savings are maximized, new standards for BCs and amended standards for EPSs could 

yield net consumer savings over the period of analysis of as much as -$70 billion and $0.25 

billion, respectively. These results assume the reference case electricity price forecast. 

Results for EPSs are shown first, using discount rates of 3 percent (Table 10.15) and 7 

percent (Table 10.16). The corresponding values for BCs are shown in Table 10.17 and Table 

10.18 (derived from manufacturer data) and Table 10.19 and Table 10.20 (derived from test and 

teardown data). In each cell, results from the reference savings case are shown in the top of the 

cell, with results from the low and high savings cases shown in parentheses in the bottom of the 

cell. Low and high results are only shown for product classes for which NPV varies between 

scenarios. 

10-18
 

EERE-2008-BT-STD-0005 COMMENT 31
 

Table 10.15 Net Present Value of Consumer Savings from Amended Standards for 

External Power Supplies at a 3 Percent Discount Rate, Manufacturer Data (2009$ 

millions) 

Product Class 

Standard Level Selected 

CSL 1 CSL 2 CSL 3 CSL 4 

A1: 0-10.25 W 332 

(261 to 335) 

315 

(212 to 496) 

322 

(202 to 562) 

160 

(29 to 457) 

A1: 10.25-39 W 637 

(391 to 807) 

1663 

(1164 to 2027) 

2155 

(1007 to 2921) 

2186 

(281 to 3402) 

A1: 39-90 W 90 

(24 to 172) 

117 

(-199 to 442) 

-606 

(-1426 to 96) 

-1785 

(-3415 to -

476) 

A1: 90-250 W -2 

(-27 to 47) 

18 

(-56 to 178) 

10 

(-81 to 205) 

-768 

(-1157 to -

183) 

A2 (DC Output, Low 

Voltage) 174 106 22 -136 

A3 (AC Output, Basic 

Voltage) 138 348 492 560 

A4 (AC Output, Low 

Voltage) 26 32 42 38 

All Class A EPSs 1394 

(986 to 1698) 

2600 

(1608 to 3631) 

2437 

(258 to 4340) 

254 

(-3800 to 

3662) 

Note: Reference case electricity prices are assumed. 

Table 10.16 Net Present Value of Consumer Savings from Amended Standards for 

External Power Supplies at a 7 Percent Discount Rate, Manufacturer Data (2009$ 

millions) 

Product Class 

Standard Level Selected 

CSL 1 CSL 2 CSL 3 CSL 4 

A1: 0-10.25 W 165 

(130 to 164) 

138 

(88 to 224) 

133 

(75 to 247) 

40 

(-24 to 183) 

A1: 10.25-39 W 311 

(180 to 400) 

819 

(556 to 1008) 

1035 

(422 to 1439) 

1012 

(-10 to 1658) 

A1: 39-90 W 41 

(6 to 82) 

29 

(-142 to 195) 

-392 

(-836 to -29) 

-1074 

(-1957 to -

393) 

A1: 90-250 W -3 

(-16 to 22) 

3 

(-37 to 84) 

-3 

(-52 to 96) 

-438 

(-649 to -136) 

A2 (DC Output, Low 

Voltage) 86 37 -14 -104 

A3 (AC Output, Basic 

Voltage) 63 161 223 248 

A4 (AC Output, Low 

Voltage) 13 16 20 18 

10-19
 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

-298 

All Class A EPSs 675 1202 1004 (-2478 to 

(462 to 830) (679 to 1724) (-161 to 1982) 1473) 

Note: Reference case electricity prices are assumed. 

Table 10.17 Net Present Value of Consumer Savings from New Standards for Battery 

Chargers at a 3 Percent Discount Rate, Manufacturer Data (2009$ millions) 

Conversion 

Type 

Battery 

Energy 

Battery 

Voltage 

Class 

ID 

Standard Level Selected 

CSL 1 CSL 2 CSL 3 

AC-DC 

<100 Wh 

Inductive 

Connection 1 121 (118 to 123) 

281 

(272 to 287) 

382 

(369 to 391) 

<4 V 2 1360 

(718 to 1654) 

-57441 

(-74744 to -

48000) 

N/A 

4<10 V 3 -39 -3957 N/A 

≥10 V 4 1291 

(265 to 2988) 

-980 

(-3283 to 2023) N/A 

100–

3000 Wh 

<20 V 5 274 

(-213 to 306) 

-277 

(-1503 to -64) 

-4026 

(-6658 to -

3293) 

≥20 V 6 0.05 -603 -2277 

>3000 Wh 7 7 

(-27 to 45) 

-37 

(-135 to 72) 

-315 

(-525 to -90) 

DC-DC <9 V Input 8 -552 -1970 N/A 

≥9 V Input 9 29 -658 N/A 

AC-AC 

AC Output 

from 

Battery 

10 898 

(857 to 923) 

1056 

(1003 to 1089) 

1211 

(1142 to 

1253) 

Note: Reference case electricity prices are assumed. 

10-20
 

EERE-2008-BT-STD-0005 COMMENT 31
 

Table 10.18 Net Present Value of Consumer Savings from New Standards for Battery 

Chargers at a 7 Percent Discount Rate, Manufacturer Data (2009$ millions) 

Conversion 

Type 

Battery 

Energy 

Battery 

Voltage 

Class 

ID 

Standard Level Selected 

CSL 1 CSL 2 CSL 3 

AC-DC 

<100 Wh 

Inductive 

Connection 1 59 

(57 to 60) 

137 

(132 to 140) 

187 

(179 to 191) 

<4 V 2 641 

(310 to 783) 

-31855 

(-41224 to -

26790) N/A 

4<10 V 3 -40 -2229 N/A 

≥10 V 4 555 

(31 to 1361) 

-762 

(-1967 to 696) N/A 

100–

3000 Wh 

<20 V 5 115 

(-124 to 132) 

-251 

(-866 to -134) 

-2349 

(-3699 to -

1948) 

≥20 V 6 -21 -370 -1298 

>3000 Wh 7 0.2 

(-16 to 16) 

-30 

(-76 to 15) 

-191 

(-292 to -96) 

DC-DC <9 V Input 8 -308 -1090 N/A 

≥9 V Input 9 7 -384 N/A 

AC-AC 

AC Output 

from 

Battery 

10 425 

(402 to 438) 

498 

(469 to 516) 

569 

(531 to 592) 

Note: Reference case electricity prices are assumed. 

10-21
 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

Table 10.19 Net Present Value of Consumer Savings from New Standards for Battery 

Chargers at a 3 Percent Discount Rate, Test and Teardown Data (2009$ millions) 

Conversion 

Type 

Battery 

Energy 

Battery 

Voltage 

Class 

ID 

Standard Level Selected 

CSL 1 CSL 2 CSL 3 

AC-DC 

<100 Wh 

Inductive 

Connection 1 No Data 

<4 V 2 N/A -2638* 

(-4342 to -1467) N/A 

4<10 V 3 No Data 

≥10 V 4 2351 

(1949 to 3744) 

3225 

(2661 to 5345) N/A 

100–

3000 Wh 

<20 V 5 570 

(293 to 570) N/A N/A 

≥20 V 6 No Data 

>3000 Wh 7 No Data 

DC-DC <9 V Input 8 No Data 

≥9 V Input 9 No Data 

AC-AC 

AC Output 

from 

Battery 

10 1232 N/A N/A 

*Values for BC product class 2 are relative to CSL 1 because CSL 0 is not defined for this product class in the test 

and teardown data.
 

Note: Reference case electricity prices are assumed.
 

10-22
 

EERE-2008-BT-STD-0005 COMMENT 31
 

 

Table 10.20 Net Present Value of Consumer Savings from New Standards for Battery 

Chargers at a 7 Percent Discount Rate, Test and Teardown Data (2009$ millions) 

Conversion 

Type 

Battery 

Energy 

Battery 

Voltage 

Class 

ID 

Standard Level Selected 

CSL 1 CSL 2 CSL 3 

AC-DC 

<100 Wh 

Inductive 

Connection 1 No Data 

<4 V 2 N/A -1845 

(-2689 to -1304) N/A 

4<10 V 3 No Data 

≥10 V 4 1136 

(950 to 1773) 

1539 

(1280 to 2509) N/A 

100–

3000 Wh 

<20 V 5 269 

(135 to 269) N/A N/A 

≥20 V 6 No Data 

>3000 Wh 7 No Data 

DC-DC <9 V Input 8 No Data 

≥9 V Input 9 No Data 

AC-AC 

AC Output 

from 

Battery 

10 608 N/A N/A 

*Values for BC product class 2 are relative to CSL 1 because CSL 0 is not defined for this product class in the test 

and teardown data.
 

Note: Reference case electricity prices are assumed.
 

10-23
 

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REFERENCES 

1 Energy Information Administration. Annual Energy Outlook 2010.
 

http://www.eia.doe.gov/oiaf/aeo/aeoref_tab.html
 2 Bradfield, M. Improving Alternator Efficiency Measurably Reduces Fuel Costs. 2008. Remy International, Inc: 

Pendleton, IN.
 3 Title 10, Code of Federal Regulations, Part 474, Subpart C – Electric and Hybrid Vehicle Research, Development, 

and Demonstration Program. June 12, 2000. (http://www.gpo.gov/fdsys/pkg/FR-2000-06-12/html/00-14446.htm) 

10-24
 

EERE-2008-BT-STD-0005 COMMENT 31
CHAPTER 11. LIFE-CYCLE COST SUBGROUP ANALYSIS
 

TABLE OF CONTENTS
 

11.1 INTRODUCTION ......................................................................................................... 11-1
 

11.2 PURCHASE PRICE IMPACTS.................................................................................... 11-1
 

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CHAPTER 11. LIFE-CYCLE COST SUBGROUP ANALYSIS
 

11.1 INTRODUCTION
 

The life-cycle cost (LCC) subgroup analysis evaluates impacts on any identifiable groups 

or customers who may be disproportionately affected by any national energy efficiency standard 

level. The U.S. Department of Energy (DOE) will conduct this analysis as one of the analyses for 

the notice of proposed rulemaking. DOE will accomplish this, in part, by analyzing the LCC and 

payback periods (PBPs) for those customers that fall into any identifiable groups. DOE plans to 

evaluate variations in regional energy prices and variations in energy use that might affect the net 

present value of a standard to customer subpopulations. To the extent possible, DOE will obtain 

estimates of each input parameter’s variability and will consider this variability in its calculation 

of customer impacts. DOE plans to perform sensitivity analyses to consider how differences in 

energy use will affect subgroups of customers. 

DOE will determine the impact on customer subgroups using the LCC spreadsheet 

model, which allows for different data inputs. The standard life-cycle cost and payback period 

analysis (described in the preliminary Technical Support Document (TSD) chapter 8) focuses on 

residential and commercial consumers that use battery chargers (BC) and external power 

supplies (EPS). DOE can use the LCC spreadsheet model to analyze the LCC for any subgroup 

by sampling only that subgroup. Model inputs used by the Department to determine LCC and 

PBPs are described in detail in the life-cycle cost and payback period analysis (see preliminary 

TSD chapter 8). 

In the case of BCs and EPSs, some possible subgroups DOE may choose to consider are: 

(1) small businesses (i.e., those with low annual revenues), (2) consumers with a high marginal 

electricity rate, (3) low-income consumers, and (4) consumers of specific applications within a 

representative unit. These subgroups may experience different economic conditions than the 

average owner of a BC or EPS. Small businesses are likely to have higher borrowing costs and 

cost of capital than larger commercial firms. Consumers with a high marginal electricity rate 

may experience very different operating costs based on new standards when compared to the 

national average electricity rate. 

11.2 PURCHASE PRICE IMPACTS 

DOE will be especially sensitive to increases in the purchase price of the equipment due 

to new standards, to avoid negative impacts on identifiable population groups that may not be 

able to afford significant increases in equipment price. For such customers that are sensitive to 

price increases, increases in first costs of a product can preclude the purchase of a new model of 

that product. As a result, some customers may retain products past their useful life. These older 

products are generally less efficient to begin with, and their efficiency may deteriorate further if 

they are retained beyond their useful life. Increases in first cost also can preclude the purchase 

and use of a product altogether, resulting in a potentially large loss of utility to the customer. 

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CHAPTER 12 PRELIMINARY MANUFACTURER IMPACT ANALYSIS 

TABLE OF CONTENTS 

12.1 INTRODUCTION........................................................................................................12-1
 

12.2 METHODOLOGY ......................................................................................................12-1
 

12.2.1 Phase I: Industry Profile.................................................................................... 12-2
 

12.2.2 Phase II: Industry Cash-Flow Analysis and Interview Guide........................... 12-2
 

12.2.2.1 Industry Cash-Flow Analysis........................................................... 12-2
 

12.2.2.2 Interview Guide ............................................................................... 12-2
 

12.2.3 Phase III: Subgroup Analysis............................................................................ 12-2
 

12.2.3.1 Manufacturer Interviews.................................................................. 12-3
 

12.2.3.2 Revised Industry Cash-Flow Analysis............................................. 12-3
 

12.2.3.3 Manufacturer Subgroup Analysis .................................................... 12-3
 

12.2.3.4 Competitive Impact Assessment...................................................... 12-3
 

12.2.3.5 Manufacturing Capacity Impact ...................................................... 12-4
 

12.2.3.6 Employment Impact......................................................................... 12-4
 

12.2.3.7 Cumulative Regulatory Burden ....................................................... 12-4
 

12.3 PRELIMINARY MANUFACTURER IMPACT ANALYSIS OVERVIEW.........12-4
 

12.3.1 Industry Overview ............................................................................................. 12-4
 

12.3.1.1 Industry Cost Structure .................................................................... 12-5
 

12.3.1.2 Inventory Levels .............................................................................. 12-6
 

12.3.2 Interview Topics and Preliminary Findings - EPS ............................................ 12-6
 

12.3.2.1 Market Shares and Industry Consolidation...................................... 12-7
 

12.3.2.2 Production and Product Mix ............................................................ 12-7
 

12.3.2.3 Conversion Costs ............................................................................. 12-8
 

12.3.2.4 Cumulative Regulatory Burden ....................................................... 12-8
 

12.3.2.5 Other Key Issues.............................................................................. 12-8
 

12.3.3 Interview Topics and Preliminary Findings - BC .............................................. 12-9
 

12.3.3.1 Market Shares and Industry Consolidation...................................... 12-9
 

12.3.3.2 Production and Product Mix ............................................................ 12-9
 

12.3.3.3 Conversion Costs ........................................................................... 12-10
 

12.3.3.4 Cumulative Regulatory Burden ..................................................... 12-10
 

12.3.3.5 Other Key Issues............................................................................ 12-10
 

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LIST OF TABLES 

TABLE 12.1 ALL OTHER MISCELLANEOUS ELECTRICAL EQUIPMENT AND 

COMPONENT MANUFACTURING INDUSTRY EMPLOYMENT AND EARNINGS...... 12-5
 

TABLE 12.2 ALL OTHER MISCELLANEOUS ELECTRICAL EQUIPMENT AND 

COMPONENT MANUFACTURING INDUSTRY MATERIAL AND PAYROLL COSTS . 12-5
 

TABLE 12.3 ALL OTHER MISCELLANEOUS ELECTRICAL EQUIPMENT AND 

COMPONENT MANUFACTURING INDUSTRY END-OF-YEAR INVENTORY ............. 12-6
 

TABLE 12.4 ALL OTHER MISCELLANEOUS ELECTRICAL EQUIPMENT AND 

COMPONENT MANUFACTURING INDUSTRY FULL PRODUCTION CAPACITY 

UTILIZATION RATES............................................................................................................. 12-6
 

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CHAPTER 12 PRELIMINARY MANUFACTURER IMPACT ANALYSIS
 

12.1 INTRODUCTION 

The purpose of the manufacturer impact analysis (MIA) is to identify and quantify the 

likely impacts of amended energy conservation standards on manufacturers. In the Notice of the 

Proposed Rulemaking (NOPR), DOE considers a wide range of quantitative and qualitative 

industry impacts that might occur due to an amended energy conservation standard. For example, 

a particular standard level could require changes in manufacturing practices, equipment, raw 

materials, etc. DOE fully analyzes these impacts during the NOPR stage of analysis. 

DOE announced changes to the preliminary analysis MIA format through a report issued 

to Congress on January 31, 2006 (as required by section 141 of the Energy Policy Act of 2005 

(EPACT 2005), entitled “Energy Conservation Standards Activities.”1 As a result, DOE collects, 

evaluates, and reports preliminary MIA information in the preliminary analysis (as opposed to 

waiting for the NOPR stage). Such preliminary information includes market data, market shares, 

industry consolidation, product mix, key issues, conversion costs, foreign competition, and 

cumulative regulatory burden information, if available. DOE solicits this information during the 

preliminary manufacturer interviews and reports the results in this chapter. Appendix 12A 

includes a copy of the interview guide that DOE distributed to manufacturers. 

To the extent appropriate for this rulemaking, DOE plans to apply the methodology 

described below to evaluate amended energy conservation standards for battery chargers (BCs) 

and external power supplies (EPSs). 

12.2 METHODOLOGY 

DOE conducts the MIA in three phases. In Phase I, DOE creates an industry profile to 

characterize the industries and conducts a preliminary MIA to identify important issues that 

require consideration. Section 12.2.1 of this chapter presents initial findings of the Phase I 

analysis. In Phase II, DOE prepares an industry cash flow model and a detailed interview 

questionnaire to guide subsequent discussions with manufacturers. In Phase III, DOE interviews 

manufacturers and assesses the impacts of amended energy conservation standards both 

quantitatively and qualitatively. DOE assesses industry and subgroup cash flow impacts and 

industry net present value (INPV) using the Government Regulatory Impact Model (GRIM). 

DOE also assesses impacts on competition, manufacturing capacity, employment, and regulatory 

burden based on manufacturer interviews and discussions. The Federal Register NOPR and 

technical support document (TSD) present results of the Phase II and III analyses. 

1 This report is available on the DOE website at: 

www.eere.energy.gov/buildings/appliance_standards/2006_schedule_setting.html. 

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12.2.1 Phase I: Industry Profile 

In Phase I of the MIA, DOE collects pertinent qualitative and quantitative financial and 

market information. This includes data on wages, employment, industry costs, and capacity 

utilization rates for manufacturers of BCs and EPSs. Sources of information include reports 

published by industry groups, trade journals, the U.S. Census Bureau, and Securities Exchange 

Commission (SEC) 10-K filings. In addition, DOE relies on information from its market and 

technology assessment, engineering analysis, life-cycle cost analysis, shipments analysis, and 

product price determination to characterize the BC and EPS manufacturing industries. 

12.2.2 Phase II: Industry Cash-Flow Analysis and Interview Guide 

In Phase II, DOE performs a preliminary industry cash-flow analysis and prepares written 

guidelines for interviewing manufacturers. 

12.2.2.1 Industry Cash-Flow Analysis 

DOE uses the GRIM to analyze the financial impacts of amended energy conservation 

standards. Amended energy conservation standards may require additional investment, higher 

production costs, and could affect revenue through higher prices and, potentially, lower 

shipments. The GRIM uses several financial parameters to determine a series of annual cash 

flows for the year that amended energy conservation standards become effective and for several 

additional years. These factors include annual expected revenues, costs of sales, selling and 

general administration expenses, taxes, and capital expenditures. Inputs to the GRIM include 

those financial parameters, manufacturing costs, shipment forecasts, and price forecasts 

developed in other analyses. The financial information is developed from publicly available data 

and confidentially submitted manufacturer information. DOE compares the GRIM results for the 

standards case at each trial standard level against the results for the base case in which no 

amended energy conservation standards are in place. The financial impact of amended energy 

conservation standards is the difference between the two sets of discounted annual cash flows. 

12.2.2.2 Interview Guide 

DOE conducts interviews with manufacturers to gather information on the effects of 

amended energy conservation standards on revenues, costs, direct employment, capital assets, 

and industry competitiveness. Before the interviews, which occur in Phase III, DOE distributes 

an interview guide to help identify the impacts of amended energy conservation standards on 

individual manufacturers or subgroups of manufacturers. Interview guide topics include: 

production costs; shipment projections; market share; product mix; conversion costs; markups 

and profitability; competition; manufacturing capacity; cumulative regulatory burden; and other 

relevant topics. 

12.2.3 Phase III: Subgroup Analysis 

Phase III activities take place after publication of the preliminary analysis. These 

activities include manufacturer interviews; revision of the industry cash-flow analysis; a 

manufacturer subgroup analysis; and an assessment of the impacts on industry competition, 

manufacturing capacity, direct employment, and cumulative regulatory burden. 

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12.2.3.1 Manufacturer Interviews 

DOE conducts detailed interviews with manufacturers to gain insight into the potential 

impacts of amended energy conservation standards on sales, direct employment, capital assets, 

and industry competitiveness. The interview process is critical to the MIA because it provides an 

opportunity for interested parties to privately express their views on important issues. Interviews 

are scheduled well in advance to provide every opportunity for stakeholders to be available for 

comment. Although a written response to the questionnaire is acceptable, DOE prefers 

interactive interviews, which help clarify responses and provide the opportunity to identify 

additional issues not specifically addressed in the interview questionnaire. A non-disclosure 

agreement allows DOE to consider confidential or sensitive information in its decision-making 

process. Confidential information will not be made available in the public record. At most, 

sensitive or confidential information may be aggregated and presented in industry-wide 

representations. 

DOE uses information gathered during manufacturer interviews to supplement the 

information gathered in Phase I and the cash flow analysis performed in Phase II. 

12.2.3.2 Revised Industry Cash-Flow Analysis 

As discussed, DOE requests information about profitability impacts, changes in capital 

expenditures, and other manufacturing impacts during the interview process. DOE revises its 

industry cash flow model based on the feedback it receives in written comments and during 

interviews. 

12.2.3.3 Manufacturer Subgroup Analysis 

Using average cost assumptions to develop an industry cash flow estimate will not 

adequately assess differential impacts among manufacturer subgroups. Smaller manufacturers, 

niche players, and manufacturers exhibiting a cost structure that differs greatly from the industry 

average could be more negatively affected. Ideally, DOE would consider the impact on every 

firm individually; however, it typically uses the results of the industry characterization to group 

manufacturers with similar characteristics. During the interviews, DOE discusses the potential 

subgroups that have been identified for the analysis. DOE asks manufacturers and other 

interested parties to suggest what subgroups or characteristics are most appropriate for the 

analysis. 

12.2.3.4 Competitive Impact Assessment 

Section 342 (6)(B)(i)(V) of the Energy Policy Act of 1992 (EPCA) directs DOE to 

consider any lessening of competition likely to result from the imposition of standards. EPCA 

further directs the U.S. Attorney General to determine the impacts, if any, of any decrease in 

competition. DOE makes a determined effort to gather and report firm-specific financial 

information and impacts. DOE bases the competitive impact assessment on manufacturer cost 

data and other information collected from interviews. When assessing competitive impacts, 

DOE’s interviews generally focus on assessing asymmetrical cost increases, the potential 

increase in business risks from an increased proportion of fixed costs, and potential barriers to 

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market entry (e.g., proprietary technologies). The competitive analysis may also focus on 

assessing any differential impacts on smaller manufacturers. 

12.2.3.5 Manufacturing Capacity Impact 

One of the significant outcomes of amended energy conservation standards can be the 

obsolescence of existing manufacturing assets, including tooling and other investments. The 

manufacturer interview guide presents a series of questions to help identify impacts on 

manufacturing capacity, specifically capacity utilization and plant location decisions in North 

America with and without amended energy conservation standards. The interview guide also 

addresses the ability of manufacturers to upgrade or remodel existing facilities to accommodate 

the new requirements; the nature and value of stranded assets, if any; and estimates for any onetime restructuring or other charges, where applicable. 

12.2.3.6 Employment Impact 

The impact of amended energy conservation standards on employment is an important 

consideration in the rulemaking process. To assess how domestic employment patterns might be 

affected, the interview process explores current employment trends in the BC and EPS industries 

and solicits manufacturer views on changes in employment patterns that may result from new or 

amended standards. The employment impacts section of the interview guide focuses on current 

employment levels at production facilities, expected future employment levels with and without 

an amended energy conservation standard, differences in workforce skills, and employee 

retraining. 

12.2.3.7 Cumulative Regulatory Burden 

DOE seeks to mitigate the overlapping effects on manufacturers of energy conservation 

standards and other regulatory actions. DOE analyzes and considers the impact on manufacturers 

of multiple, product-specific regulatory actions. 

12.3 PRELIMINARY MANUFACTURER IMPACT ANALYSIS OVERVIEW 

During the preliminary analysis phase, DOE conducted a preliminary evaluation of the 

impact of potential new and amended energy conservation standards on the BC and EPS 

industries. 

The primary sources of information for this analysis are the U.S. Census, industry 

reports, and interviews with manufacturers of EPSs and BCs, conducted in late 2009 and early 

2010. To maintain confidentiality, DOE only reports aggregated information here. DOE does not 

disclose company-specific information, nor does it identify the individual manufacturers that 

disclosed information. 

12.3.1 Industry Overview 

The following section summarizes publicly available industry data. 

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12.3.1.1 Industry Cost Structure 

DOE is unaware of any publicly available industry-wide cost data specific to only 

manufacturers of BCs and EPSs. BC and EPS manufacturing is classified as a subset under the 

North American Industry Classification System (NAICS) code 335999 (All Other Miscellaneous 

Electrical Equipment and Component Manufacturing). Therefore, DOE presents the data below 

as a broader industry proxy for the BC and EPS industries, which, in combination with 

information gained in interviews, inform DOE’s analysis of the industry cost structures. For 

simplicity, DOE will refer to these broader categories by the products they represent, namely 

BCs and EPSs. DOE obtained the below data from U.S. Census Bureau, Annual Survey of 

Manufacturers, Statistics for Industry Groups and Industries from 2002-2006. 

Table 12.1 presents the employment levels and earnings from 2002 to 2006. The statistics 

illustrate approximately a 40-percent decrease in production workers from 2002 to 2006. The 

statistics show a 36-percent decrease in the overall number of employees from 2002 to 2006. 

Table 12.1 All Other Miscellaneous Electrical Equipment and Component Manufacturing 

Industry Employment and Earnings 

Year Production Workers All Employees Annual Payroll 

($000s) 

2002 30,475 49,388 1,969,580 

2003 26,571 43,078 1,862,507 

2004 25,394 42,123 1,962,922 

2005 18,429 32,376 1,558,132 

2006 18,385 31,786 1,589,923 

U.S. Census Bureau. Annual Survey of Manufacturers, 2002-2006 

Table 12.2 presents the costs of materials and industry payroll as a percentage of 

shipment value from 2002 to 2006. The cost of materials as a percentage of shipment value has 

steadily decreased from 2002 to 2006. During the 2002 to 2006 period, the cost of payroll for 

production workers and the cost of total payroll have declined by 33.0 percent and 23.1 percent, 

respectively. 

Table 12.2 All Other Miscellaneous Electrical Equipment and Component Manufacturing 

Industry Material and Payroll Costs 

Year Cost of Materials 

(percent of shipment value) 

Cost of Payroll 

for Production Workers 

(percent of shipment value) 

Cost of Total Payroll 

(percent of shipment value) 

2002 52.78 12.66 28.51 

2003 52.67 11.94 27.26 

2004 53.89 12.38 28.32 

2005 44.67 8.89 22.12 

2006 46.11 8.48 21.92 

U.S. Census Bureau. Annual Survey of Manufacturers, 2002-2006 

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12.3.1.2 Inventory Levels 

Table 12.3 shows the year-end inventory levels obtained from the U.S. Census Bureau, 

Annual Survey of Manufacturers, Statistics for Industry Groups and Industries from 2002 to 

2006. Again, DOE presents these data as a broader measure of the BC and EPS industries. The 

industries’ end-of-year inventory from 2002 to 2006 decreased when expressed both in dollars 

and as a percentage of shipment value. 

Table 12.3 All Other Miscellaneous Electrical Equipment and Component Manufacturing 

Industry End-of-Year Inventory 

Year End-of-Year Inventory 

($000s) 

End-of-Year Inventory 

(percent of shipment value) 

2002 1,847,565 26.75 

2003 1,769,259 25.90 

2004 1,738,681 25.08 

2005 1,382,601 19.63 

2006 1,376,288 18.98 

U.S. Census Bureau. Annual Survey of Manufacturers, 2002-2006 

DOE obtained full production capacity utilization rates from the U.S. Census Bureau, 

“Current Industrial Reports,” Survey of Plant Capacity from 2002 to 2006. Table 12.4 presents 

production capacity utilization rates for NAICS code 335999. Full production capacity is defined 

as the maximum level of production an establishment can attain under normal operating 

conditions. In the Survey of Plant Capacity report, the full production capacity utilization rate is 

a ratio of the actual level of operations to the full production level. 

Table 12.4 All Other Miscellaneous Electrical Equipment and Component Manufacturing 

Industry Full Production Capacity Utilization Rates 

Year All Other Miscellaneous Electrical Equipment and Component 

Manufacturing (%) 

2002 57 

2003 62 

2004 61 

2005 70 

2006 66 

U.S. Census Bureau. 2007 Current Industrial Reports: Table 1a - Full Production Capacity 

Utilization Rates by Industry: Fourth Quarters 2002 through 2006. November 2007 

12.3.2 Interview Topics and Preliminary Findings - EPS 

The following section summarizes information gathered during interviews held during 

the fourth quarter of 2009 for the preliminary MIA. 

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12.3.2.1 Market Shares and Industry Consolidation 

Amended energy conservation standards can alter the competitive dynamics of the 

marketplace, prompting companies to enter the market, exit the market, or merge with other 

companies. The preliminary MIA interview questions asked manufacturers to share their 

perspectives on industry consolidation both in the absence of amended energy conservation 

standards and assuming amended standards at various efficiency levels. The interview questions 

focused on gathering information that assessed: 

 current and anticipated market share in the event of standards; 

 potential disproportionate cost increases to some manufacturers; 

 likelihood of industry consolidation; 

 increased proportion of fixed costs potentially increasing business risks; and 

 potential barriers to market entry (e.g., proprietary technologies). 

The need to assess anti-competitive effects of proposed amended energy conservation 

standards derives from the need to protect consumer interests. During the interviews, DOE also 

solicited information to determine whether amended energy conservation standards could result 

in disproportionate economic or performance penalties for particular consumer or user 

subgroups. Manufacturers were also asked if amended energy conservation standards could 

result in products that would be more or less desirable to consumers due to changes in product 

functionality, utility, or other features. 

Market Shares: DOE inquired about the current market shares of manufacturers in the 

EPS industry and how those shares might change after amended energy conservation standards. 

One manufacturer noted that new standards would not change market shares because improving 

energy efficiency is now a primary design goal and most of the industry is already actively 

marketing the efficiency aspect of their designs. A separate manufacturer believed that those 

manufacturers that are already producing products close to the new standard levels could see a 

short-term rise in market share until the rest of the market has time to adjust to the new 

standards. One manufacturer expected some weaker companies to exit the industry due to the 

new standards but did not expect that occurrence to have a long-term impact on market share. 

Industry Consolidation: The EPS industry is relatively fragmented but has seen a 

consolidation trend in recent years. Manufacturers were split on whether a new standard would 

lead to any consolidation. Some believed that a standard could contribute a small amount to the 

consolidation trend while others did not expect a new standard to have any effect on 

consolidation. All agreed that any consolidation resulting from a new standard would be 

insignificant. 

12.3.2.2 Production and Product Mix 

DOE requested manufacturers’ feedback on what they perceived to be the possible 

impact of amended energy conservation standards on manufacturers’ products. New standards 

could result in a change in manufacturers’ product mix or a change in the products’ utility to 

consumers. Higher energy conservation standards could also result in higher per-unit costs that 

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could cause consumers to shift to less expensive alternative products, if such products were 

available. 

Product Differentiation: Manufacturers discussed the factors that differentiate the 

products in the market. One manufacturer noted that product differentiators are changing because 

of a maturation of the market which has been driven by increased communication. Prior to this 

development, OEMs largely purchased EPSs from manufacturers with whom they had long 

relationships. Due to the increased communication, trust in performance is increasing and OEMs 

now base more of their purchasing decisions on price and brand. 

Product Mix: The EPS manufacturers did not expect a new standard to have a 

significant effect on the industry’s product mix. 

Product Utility: Manufacturers believed that new standards would have a positive effect 

on product utility. One manufacturer stated that as EPSs become more energy efficient, they can 

be produced in smaller sizes. This would improve consumers’ product utility. One manufacturer 

disagreed, stating that new standards could result in larger enclosures for EPSs as well as less 

flexible power cords. Both of these outcomes would decrease utility for consumers. 

12.3.2.3 Conversion Costs 

None of the manufacturers interviewed believed that a new standard would require 

significant capital or product conversion costs. Manufacturers mentioned that they would expect 

capital or product conversion costs to be very low for any of the proposed standards. 

12.3.2.4 Cumulative Regulatory Burden 

The mobile phone industry is in the process of attempting to implement a universal EPS 

to be used with mobile phones. This initiative would allow consumers to purchase one EPS that 

could be used with any new mobile phone. Because the mobile phone industry is currently 

structured so that each mobile phone requires an EPS that is unique to the model, a universal 

EPS has the potential to drastically reduce future shipments of EPSs for mobile phones. The new 

universal EPS structure has a target date of 2012. 

New safety regulations could force manufacturers of EPSs used in medical products 

(designated as non-Class A EPSs) to provide more reporting on safety issues. One manufacturer 

commented that the new safety standard could be implemented without much cost to 

manufacturers. 

12.3.2.5 Other Key Issues 

The preliminary MIA gives DOE the opportunity to identify other key manufacturer 

issues early in the development of amended energy conservation standards. During preliminary 

interviews, manufacturers identified several major issues that are detailed in the following 

sections. 

Shipments: Shipment projections can be a significant factor in determining the 

manufacturing impacts of amended energy conservation standards. The interviews provide an 

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opportunity for manufacturers to share information that can help DOE quantify the magnitude of 

any changes in shipments resulting from amended energy conservation standards. 

A few manufacturers stated that exceptionally stringent standards could cause costs (and 

subsequently, prices) to reach a point where consumers could decide that the product was too 

expensive. Potentially, this could cause consumers to migrate to lower priced products or delay 

purchases altogether. However, none of the manufacturers expected the standards to be close to a 

level where price would become a concern for consumers. All of the manufacturers felt that the 

new standards would cause insignificant increases in product costs or even possibly lower 

product costs. Neither scenario would have negative effects on industry shipments. 

Timing: Some manufacturers expressed concerns that if new standards were 

implemented too quickly, manufacturers may not have enough time to produce and sell all 

remaining inventory at the prior efficiency level. In such a case, manufacturers would be forced 

to write down inventory due to product obsolescence. One manufacturer estimated that the 

company would need at least six months notice prior to a standard implementation—significantly 

less time than is usually provided for manufacturers to adjust to new standards. Another 

manufacturer noted that the rulemaking needed to be relevant with the best technology currently 

available. That is, because of the lag between the announcement of new standards and their 

implementation, this manufacturer had concerns that new standards could be implemented after 

the industry had already reached higher efficiency levels. 

12.3.3 Interview Topics and Preliminary Findings - BC 

The following section summarizes information gathered during interviews held during 

the first quarter of 2010 for the preliminary MIA. 

12.3.3.1 Market Shares and Industry Consolidation 

Market Shares: DOE inquired about current market shares of manufacturers in the BCs 

industry and how those shares might change after amended energy conservation standards. The 

BCs industry is fragmented with few manufacturers owning more than a small portion of market 

share. Within a few of the consumer product segments, a couple of manufacturers do control a 

significant percentage of the market; however, as a percentage of the entire BC market, their 

market share is much smaller. 

Industry Consolidation: Due to the current state of the economy, many smaller 

manufacturers are facing financial difficulties. One manufacturer commented that if the economy 

continues to suffer, the smallest manufacturers may be forced to close. Multiple manufacturers 

believed that new standards could adversely affect small manufacturers, especially if those 

manufacturers are domestic. 

12.3.3.2 Production and Product Mix 

Product Differentiation: The vast majority of BCs are sold to consumers as part of a 

larger consumer product. Because consumers make product decisions based on the product as a 

whole, differences in BCs sometimes go unnoticed. One manufacturer stated that consumers 

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make purchasing decisions based on the product as whole while simply expecting the BC to 

work well. As a result, the energy efficiency of BCs is not a primary consumer consideration. 

According to multiple manufacturers, the main differentiator for consumers in selecting 

products that utilize BCs is price, especially in a weak economy. One manufacturer stated that 

product quality was the second most important differentiator. Although some manufacturers do 

engineer their products to be more energy efficient, the manufacturers’ efforts are a result of their 

own concerns about energy efficiency and are not driven by consumer demand. 

Product Mix: The manufacturers of BCs did not indicate that a new standard would 

have a significant effect on the industry’s product mix. 

Product Utility: Manufacturers of BCs believed that new standards would have a 

positive effect on product utility, albeit minor. One manufacturer stated that as BCs become 

more energy efficient, they can be produced to be smaller and lighter. This would produce a 

positive change in product utility. 

12.3.3.3 Conversion Costs 

Several manufacturers stated that they expected to incur significant product conversion 

costs to develop products that complied with new standards. The cost and time required for 

safety approval and testing were mentioned by multiple manufacturers. If the standards were too 

stringent, manufacturers commented that there could also be some capital conversion costs. One 

manufacturer noted that if the standards were to push the market towards high frequency 

technology, manufacturing could shift more to Asia, resulting in stranded domestic assets. 

12.3.3.4 Cumulative Regulatory Burden 

One manufacturer expressed concern that recent attempts by the US Department of 

Transportation to harmonize safety and transportation regulations with those established by the 

United Nations could require the manufacturer to add more circuitry to its BCs. Adding circuitry 

would make it more difficult for the manufacturer to improve the energy efficiency of its BCs. 

12.3.3.5 Other Key Issues 

Uniformity and Clarity of Requirements: Almost all of the manufacturers expressed 

concern over competitors finding ways to avoid the most stringent requirements of a new 

standard. One manufacturer commented that at present, there are a substantial number of 

competitors who do not attempt to get safety approval for their products and release them to the 

market anyway. The manufacturer’s concern was that additional regulations without clear and 

enforceable requirements could further disadvantage manufacturers who abide by the laws. 

Another manufacturer stated that if testing requirements were too complex, some competitors 

may find ways to avoid the most stringent requirements by exploiting loopholes or a lack of 

clarity in the testing requirements. 

Profit Margins: Multiple manufacturers stated that new standards could significantly 

raise product costs and hurt their profit margins. A manufacturer explained that profit margins 

were already exceptionally low due to the weakness in the economy. A different manufacturer 

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stated that the industry was unable to pass on increases in product costs to consumers. 

Consequently, the industry faces decreasing profit margins whenever it experiences an increase 

in product costs. Because cost is the biggest differentiator in BCs, if a manufacturer cannot 

maintain its pricing structure, the manufacturer can rapidly lose market share. 

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CHAPTER 13. UTILITY IMPACT ANALYSIS
 

TABLE OF CONTENTS
 

13.1 INTRODUCTION ..................................................................................................................1
 

13.2 METHODOLOGY .................................................................................................................1
 

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CHAPTER 13. UTILITY IMPACT ANALYSIS 

13.1 INTRODUCTION 

The U.S. Department of Energy (DOE will analyze specific effects of its proposed 

standard levels on the electric industry as part of the notice of proposed rulemaking analyses, 

using a variant of the U.S. DOE /Energy Information Administration (EIA)’s National Energy 

Modeling System (NEMS). The NEMS is a large, multi-sectoral, partial equilibrium model of 

the U.S. energy sector. EIA uses NEMS to produce the Annual Energy Outlook (AEO)1

. NEMS 

produces a widely recognized baseline energy forecast for the United States, and this energy 

forecast is available in the public domain. DOE will use a variant known as NEMS-BT to 

provide key inputs to the analysis.a 

The utility impact analysis will consist of a comparison between model results for the 

base case and for policy cases in which proposed standards are in place. The use of NEMS-BT 

for the utility analysis offers several advantages. As the official DOE energy forecasting model, 

NEMS relies on a set of assumptions that are transparent and have received wide exposure and 

commentary. NEMS-BT allows an estimate of the interactions between the various energy 

supply and demand sectors and the economy as a whole. The utility impact analysis will report 

the changes in installed capacity and generation, by fuel type, that result for each trial standard 

level, as well as changes in electricity sales to the residential sector. 

DOE will conduct the utility impact analysis as a policy deviation from the 2010 version 

of the AEO (AEO2010), applying the same basic set of assumptions. For example, the operating 

characteristics (e.g., energy conversion efficiency, emissions rates) of future electricity 

generating plants are as specified in the AEO2010 reference case. 

DOE also will explore deviation from some of the reference case assumptions to 

represent alternative futures. Two alternative scenarios use the high and low economic growth 

cases of AEO2010. The reference case corresponds to medium growth. As part of varying 

supply-side growth determinants in these cases, AEO2010 also varies the forecasted energy 

prices for all three economic growth cases. Different economic growth scenarios will affect the 

rate of growth of energy demand. 

13.2 METHODOLOGY 

The electric utility impact analysis will consist of NEMS-BT forecasts for generation by 

plant type, installed capacity, sales, and prices. NEMS provides reference case load shapes for 

several end uses. The model uses predicted growth in demand for each end use to build up a 

projection of the total electric system load growth for each region, which it uses in turn to predict 

the necessary additions to capacity. DOE uses NEMS-BT to account for the implementation off 

a For more information on NEMS, please refer to the U.S. Department of Energy, Energy Information 

Administration documentation. A useful summary is National Energy Modeling System: An Overview 2003, 

DOE/EIA-0581 (2003), March 2003. EIA approves use of the name NEMS to describe only an official version of 

the model without any modification to code or data. Because this analysis entails some minor code modifications 

and the model is run under various policy scenarios that are variations on EIA assumptions, DOE refers to the model 

by the name NEMS-BT (BT is DOE’s Building Technologies Program, under whose aegis this work has been 

performed). NEMS-BT was previously called NEMS-BRS. 

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energy conservation standards by decrementing the appropriate reference case load shape. DOE 

will determine the size of the decrement using data for the per-unit energy savings developed in 

the life-cycle cost analysis (chapter 8) and the forecast of shipments developed for the national 

impact analysis (chapter 9). 

The predicted reduction in electric capacity additions is sensitive to the peak load impacts 

of the standard. DOE will investigate the need to adjust the hourly load profiles that include 

battery chargers and external power supplies in NEMS-BT. 

Since the AEO2010 version of NEMS forecasts only to the year 2030, DOE must 

extrapolate results to 2055. DOE conducts an extrapolation to 2055 to be consistent with the 

analysis period being used by DOE in the national impact analysis (NIA). It will not be feasible 

to extend the forecast period of NEMS-BT for the purposes of this analysis, nor does EIA have 

an approved method for extrapolation of many outputs beyond 2030. While it might seem 

reasonable in general to make simple linear extrapolations of results, in practice this is not 

advisable because outputs could be contradictory. For example, changes in the fuel mix implied 

by extrapolations of those outputs could be inconsistent with the extrapolation of marginal 

emissions factors. An analysis of various trends sufficiently detailed to guarantee consistency is 

beyond the scope of this work and, in any case, would involve a great deal of uncertainty. 

Therefore, for all extrapolations beyond 2030, DOE intends to use simple replications of year 

2030 results; in this way results are guaranteed to be consistent. As with the AEO reference case 

in general, the implicit assumption is that the regulatory environment does not deviate from the 

current known situation during the extrapolation period. Only changes that have been announced 

with date-certain introduction are included in NEMS-BT. 

Results of the analysis will include changes in residential electricity sales and installed 

capacity and generation by fuel type for each trial standard level, in five-year forecasted 

increments extrapolated to 2055. 

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1 

REFERENCES 

Energy Information Administration, Annual Energy Outlook 2010 with Projections to 

2035, March 2010. Washington, DC. Report No. DOE/EIA-0383(2010). 

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CHAPTER 14. EMPLOYMENT IMPACT ANALYSIS
 

TABLE OF CONTENTS
 

14.1 INTRODUCTION ............................................................................................................ 14-1
 

14.2 METHODOLOGY ........................................................................................................... 14-1
 

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CHAPTER 14. EMPLOYMENT IMPACT ANALYSIS
 

14.1 INTRODUCTION
 

The U.S. Department of Energy (DOE)’s employment impact analysis estimates national 

job creation or job elimination resulting from possible new standards, due to reallocation of the 

associated expenditures for purchasing and operating equipment. DOE will conduct this analysis 

as one of the analyses for the notice off proposed rulemaking (NOPR). DOE will estimate 

national impacts on major sectors of the U.S. economy, using publicly available data. DOE will 

make all methods and documentation available for review. 

Energy conservation standards can impact employment both directly and indirectly. 

Direct employment impacts are changes in the number of employees at the plants that produce 

the covered products, along with the affiliated distribution and service companies, resulting from 

standards. DOE will evaluate direct employment impacts in its manufacturer impact analysis, as 

described in chapter 12. This analysis covers indirect employment impacts which may result 

from expenditures shifting between goods (the substitution effect) and changes in income and 

overall expenditure levels (the income effect) that occur due to the implementation of standards. 

DOE expects new energy conservation standards to decrease energy consumption, and 

therefore to reduce expenditures for energy. The savings in energy expenditures may be spent on 

new investment and other items. The standards may increase the purchase price of products, 

including the retail price plus sales tax, and increase installation costs. 

Using an input-output model of the U.S. economy, this analysis seeks to estimate the 

year-to-year effect of these expenditure impacts on net economic output and employment. DOE 

intends the employment impact analysis to quantify the indirect employment impacts of these 

expenditure changes. 

14.2 METHODOLOGY 

To investigate the combined direct and indirect employment impacts, DOE will use the 

Pacific Northwest National Laboratory (PNNL)’s ‘Impact of Sector Energy Technologies’ 

(ImSET) model.1 PNNL developed ImSET, a spreadsheet model of the U.S. economy that 

focuses on 188 sectors most relevant to industrial, commercial, and residential building energy 

use, for DOE’s Office of Energy Efficiency and Renewable Energy. ImSET is a special-purpose 

version of the U.S. Benchmark National Input-Output (I-O) model, which has been designed to 

estimate the national employment and income effects of energy saving technologies that are 

deployed by DOE’s Office of Energy Efficiency and Renewable Energy. In comparison with the 

previous versions of the model used in earlier rulemakings, this version allows for more 

complete and automated analysis of the essential features of energy efficiency investments in 

buildings, industry, transportation, and the electric power sectors. 

The ImSET software includes a computer-based I-O model with structural coefficients to 

characterize economic flows among the 188 sectors. ImSET’s national economic I-O structure is 

based on the 1997 Benchmark U.S. table, specially aggregated to 188 sectors.2 

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DOE intends to use the ImSet model to estimate changes in employment, industry output, 

and wage income in the overall U.S. economy resulting from changes in expenditures in the 

various sectors of the economy. DOE designed the employment impact analysis to estimate the 

year-to-year net national employment effect of these different expenditure flows. 

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REFERENCES 

1. Roop, J. M., M. J. Scott, and R. W. Schultz. ImSET: Impact of Sector Energy Technologies. 

2005. Pacific Northwest National Laboratory: Richland, WA. Report No. PNNL–15273. 

2. Lawson, A. M., K. S. Bersani, M. Fahim-Nader, and J. Guo. Benchmark Input-Output 

Accounts of the U. S. Economy, 1997. In Survey of Current Business. December 2002: pp. 

19–117. 

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