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Energy Conservation

Standards for Battery

Chargers and Class A External

Power Supplies

This page presents additional information on

energy conservation standards, the upcoming

public meeting, instructions

for submitting comments, contact information,

and more for Docket Number EERE-2008-

BT-STD-0005.

Return to the Battery Charger and External

Power Supplies page for information on all

of the U.S. Department of Energy's

(DOE) activities related to these products.

Background

Section 301 of the Energy Independence and

Security Act of 2007 (EISA) establishes

standards for Class A EPSs effective July 1,

2008, and directs DOE to conduct two

successive rulemakings to review and possibly

amend the energy conservation standards for

external power supplies, the first of which is

to be completed by July 1, 2011.

Section 309 of EISA requires DOE to issue a

final rule prescribing energy conservation

standards for BCs, if technologically feasible

and economically justified, by July 1, 2011.

(42 U.S.C. 6295(u)(1)(E)(i)(II))

DOE is bundling the battery charger

rulemaking proceeding with a review and

possible amendment to the energy

conservation standards for Class A external

power supplies.

Current Rulemaking

DOE has issued a notice of public meeting and

availability of framework document. In the

notice, DOE outlines its plans for developing

new energy conservation standards for battery

chargers, and for reviewing and possibly

amending energy conservation standards for

external power supplies. In addition, DOE has

developed a supplemental draft technical

report, which describes past DOE analysis on

battery chargers and external power supplies.

Notice of Public Meeting and Availability

of Framework Document (PDF 48 KB)

Appliances and Commercial Equipment Standards: Energy Conservation S... http://www1.eere.energy.gov/buildings/appliance_standards/residential/b...

1 of 2 6/4/2009 8:59 AM

EERE-2008-BT-STD-0005 COMMENT 03
Framework Document Public Meeting

Framework Document (PDF 1.7 MB)

Draft Technical Report (PDF 1.3 MB)

Contact Information

Victor Petrolati

Project Manager

(202) 586-4549

Printable Version

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Content Last Updated: 05/28/2009

Appliances and Commercial Equipment Standards: Energy Conservation S... http://www1.eere.energy.gov/buildings/appliance_standards/residential/b...

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EERE-2008-BT-STD-0005 COMMENT 03
1

 [6450-01-P] 

DEPARTMENT OF ENERGY 

Office of Energy Efficiency and Renewable Energy 

10 CFR Part 430 

(Docket No. EERE-2008-BT-STD-0005) 

RIN: 1904-AB57 

Energy Efficiency Program for Consumer Products: Public Meeting and Availability of 

Framework Document for Battery Chargers and External Power Supplies 

AGENCY: Office of Energy Efficiency and Renewable Energy, Department of Energy. 

ACTION: Notice of public meeting and availability of a Framework Document. 

SUMMARY: The U.S. Department of Energy (DOE) is initiating a rulemaking process to 

consider establishing new energy conservation standards for battery chargers and amending the 

energy conservation standards for Class A external power supplies, as directed by the Energy 

Independence and Security Act of 2007 (EISA). Accordingly, DOE will hold an informal public 

meeting to discuss and receive comments on its planned analytical approach and issues it will 

address in this rulemaking proceeding. DOE also welcomes written comments from the public 

concerning this rulemaking. To inform interested parties and to facilitate this process, DOE has 

EERE-2008-BT-STD-0005 COMMENT 03
2

prepared two documents: a framework document, which explains the analytical approach and 

identifies particular issues on which DOE is interested in receiving comment; and a draft 

technical report, which details DOE’s research and analysis on these products to date. Copies of 

these and all other documents associated with this rulemaking are available at 

www.eere.energy.gov/buildings/appliance_standards/residential/battery_external.html. 

DATES: DOE will hold a public meeting in Washington, D.C., beginning on July 16, 2009, 

from 9 a.m. to 5 p.m.. The agenda for the public meeting will include the energy conservation 

standards rulemaking on battery chargers and external power supplies. DOE must receive 

requests to speak at this public meeting no later than 4 p.m., Thursday, July 2, 2009. DOE must 

receive a signed original and an electronic copy of statements to be given at the public meeting 

no later than 4 p.m., Thursday, July 9, 2009. Written comments on the framework document are 

welcome, especially following the public meeting, and should be submitted by [INSERT DATE 

45 DAYS AFTER PUBLICATION OF THIS NOTICE]. 

ADDRESSES: The public meeting will be held at the U.S. Department of Energy, Forrestal 

Building, Room 1E-245, 1000 Independence Avenue, SW, Washington, DC 20585-0121. Please 

note that foreign nationals participating in the public meeting are subject to advance security 

screening procedures. If a foreign national wishes to participate in the public meeting, please 

inform DOE as soon as possible by contacting Ms. Brenda Edwards at (202) 586-2945 so that 

the necessary procedures can be completed. 

EERE-2008-BT-STD-0005 COMMENT 03
3

Interested parties may submit comments, identified by docket number EERE-2008-BTSTD-0005 and/or Regulation Identifier Number (RIN) 1904-AB57, by any of the following 

methods: 

 Federal eRulemaking Portal: www.regulations.gov. Follow the instructions for 

submitting comments. 

 E-mail: BC&EPS_ECS@ee.doe.gov. Include docket number EERE-2008-BT-STD0005 and/or RIN 1904-AB57 in the subject line of the message. 

 Mail: Ms. Brenda Edwards, U.S. Department of Energy, Building Technologies 

Program, Mailstop EE-2J, Framework Document for Battery Chargers and External 

Power Supplies, docket number EERE-2008-BT-STD-0005 and/or RIN 1904-AB57, 

1000 Independence Avenue, SW., Washington, DC 20585-0121. Please submit one 

signed paper original. 

 Hand Delivery/Courier: Ms. Brenda Edwards, U.S. Department of Energy, Building 

Technologies Program, 6th Floor, 950 L’Enfant Plaza, SW, Washington, DC 20024. 

Please submit one signed paper original. 

Instructions: All submissions received must include the agency name and docket number 

or RIN for this rulemaking. 

Docket: For access to the docket to read background documents or comments received, 

go to the U.S. Department of Energy, Resource Room of the Building Technologies Program, 

Sixth Floor, 950 L’Enfant Plaza, SW., Washington, DC 20024, (202) 586-2945, between 9 a.m. 

EERE-2008-BT-STD-0005 COMMENT 03
4

and 4 p.m., Monday through Friday, except Federal holidays. Please call Ms. Brenda Edwards 

first at the above telephone number for additional information about visiting the Resource Room. 

FOR FURTHER INFORMATION CONTACT: Mr. Victor Petrolati, U.S. Department of 

Energy, Office of Energy Efficiency and Renewable Energy, Building Technologies, EE-2J, 

1000 Independence Avenue, SW., Washington, DC 20585-0121. Telephone: (202) 586-4549. Email: Victor.Petrolati@ee.doe.gov.

 Mr. Michael Kido, U.S. Department of Energy, Office of the General Counsel, GC-72, 

1000 Independence Avenue, SW., Washington, DC 20585. Telephone: (202) 586-9507. E-mail: 

mailto:Michael.Kido@hq.doe.gov. 

 For information on how to submit or review public comments and on how to participate 

in the public meeting, contact Ms. Brenda Edwards, U.S. Department of Energy, Office of 

Energy Efficiency and Renewable Energy, Building Technologies Program, EE-2J, 1000 

Independence Avenue, SW., Washington, DC, 20585-0121. Telephone (202) 586-2945. E-mail: 

Brenda.Edwards@ee.doe.gov. 

SUPPLEMENTARY INFORMATION: 

Title III of the Energy Policy and Conservation Act (EPCA), as amended (42 U.S.C. 

6291 et seq.), sets forth a variety of provisions designed to improve energy efficiency. Part B of 

Title III (42 U.S.C. 6291–6309), subsequently renamed Part A, established the “Energy 

EERE-2008-BT-STD-0005 COMMENT 03
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Conservation Program for Consumer Products Other Than Automobiles.”1 The consumer 

products subject to this program are referred to as “covered products.” 

Section 135 of the Energy Policy Act of 2005 (EPACT 2005), Pub. L. 109-58, amended 

sections 321 and 325 of EPCA, by defining battery chargers and external power supplies and 

directing the Secretary to prescribe “definitions and test procedures for the power use of battery 

chargers and external power supplies” and to “issue a final rule that determines whether energy 

conservation standards shall be issued for battery chargers and external power supplies or classes 

of battery chargers and external power supplies.” (42 U.S.C. 6295(u)(1)(A) and (E)) 

On December 8, 2006, DOE complied with the first of these requirements by publishing a 

final rule that prescribed test procedures for a variety of products. 71 FR 71340. That rule, 

which is currently codified in multiple sections of the Code of Federal Regulations (CFR), 

included definitions and test procedures for battery chargers and external power supplies. The 

test procedures for battery chargers and external power supplies are found in 10 CFR Part 430, 

Subpart B, Appendix Y (“Uniform Test Method for Measuring the Energy Consumption of 

Battery Chargers”) and 10 CFR Part 430, Subpart B, Appendix Z (“Uniform Test Method for 

Measuring the Energy Consumption of External Power Supplies.”), respectively. 

DOE subsequently published a notice of public meeting and availability of 

documentation for public review on December 29, 2006. 71 FR 78389. This public meeting, 

called a “Scoping Workshop,” discussed DOE’s plans for conducting a determination analysis 

for battery chargers and external power supplies. The Scoping Workshop was held at DOE’s 

Forrestal Building in Washington, DC, on January 24, 2007. Information pertaining to the 

1

 This part was originally titled Part B but it was redesignated Part A in the United States Code for editorial reasons. 

EERE-2008-BT-STD-0005 COMMENT 03
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Scoping Workshop can be found on DOE’s website at 

www.eere.energy.gov/buildings/appliance_standards/residential/battery_external.html. 

On December 19, 2007, Congress enacted the Energy Independence and Security Act of 

2007 (EISA), Pub. L. 110-140, which amended, among others, sections 321, 323, and 325 of 

EPCA. While EPACT 2005 amended EPCA by defining an external power supply 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” (42 U.S.C. 6291(36)(A)), section 301 

of EISA amended this definition by creating a subset of external power supplies called “Class A 

External Power Supplies”—those external power supplies that are “able to convert to only 1 AC 

or DC output voltage at a time” and that have “nameplate output power that is less than or equal 

to 250 watts.” (42 U.S.C. 6291(36)(C)(i)) Section 301 of EISA also established for these 

products energy conservation standards that became effective on July 1, 2008, and directed DOE 

to conduct an energy conservation standards rulemaking to review those standards by July 1, 

2011. 

Additionally, section 309 of EISA amended section 325(u)(1)(E) of EPCA by directing 

DOE to issue a final rule that prescribes energy conservation standards for battery chargers or 

classes of battery chargers or to determine that no energy conservation standard is 

technologically feasible and economically justified. DOE is bundling together this battery 

charger rulemaking proceeding with the requirement to review and consider amending the 

energy conservation standards for Class A external power supplies, as both rulemakings must be 

completed by July 1, 2011. The new rulemaking requirements contained in sections 301 and 309 

EERE-2008-BT-STD-0005 COMMENT 03
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of EISA effectively supersede the prior determination analysis that EPACT 2005 required DOE 

to conduct. 

Section 309 of EISA also instructed DOE to “issue a final rule that determines whether 

energy conservation standards shall be issued for external power supplies or classes of external 

power supplies” no later than two years after EISA’s enactment. (42 U.S.C. 6295(u)(1)(E)(i)(I)) 

Because DOE cannot conduct a determination analysis on whether it should issue energy 

conservation standards for a product for which standards have already been set, DOE is 

interpreting these sections jointly as a requirement to determine, in a separate rulemaking to be 

completed by December 19, 2009, whether energy conservation standards shall be issued for 

non-Class A external power supplies. Examples of these types of external power supplies include 

those with nameplate output power greater than 250 watts, those that are able to convert to more 

than one AC or DC output voltage at the same time, and those that are specifically excluded from 

coverage under the Class A external power supply definition provided by EISA by virtue of their 

application (e.g., EPSs used with medical devices). 

 Finally, section 310 of EISA established definitions for active mode, standby mode, and 

off mode, and directed DOE to amend its existing test procedures for both BCs and EPSs to 

measure the energy consumed in standby mode and off mode. (42 U.S.C. 6295(gg)(2)(B)(i)) 

DOE satisfied this requirement by publishing a final rule that incorporated standby and off mode 

measurement into the DOE test procedure. 74 FR 13318 (March 27, 2009). 

To initiate the bundled battery charger and Class A external power supply rulemaking, 

DOE has prepared a Framework Document to explain the issues, analyses, inputs, and processes 

it anticipates will arise in developing new energy conservation standards for battery chargers and 

EERE-2008-BT-STD-0005 COMMENT 03
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amended energy conservation standards for Class A external power supplies. In addition, DOE 

has prepared a draft technical report that presents DOE’s research, analysis, and methods on both 

these products as part of its work on the determination analysis in 2007. The publication of this 

draft technical report is not intended to set any new precedent for framework document 

meetings. Instead, DOE believes that it may receive better comment and more precise direction 

from interested parties on key issues by publishing its previously developed draft analyses in 

conjunction with this framework document. As discussed earlier, the work on the determination 

was overtaken by the changes introduced by EISA, which modified both its scope and schedule. 

As noted above, DOE will hold a public meeting on Thursday, July 16, 2009, in 

Washington, DC, to discuss the analyses presented and issues identified in the Framework 

Document. At the public meeting, the Department will make a number of presentations, invite 

discussion on the rulemaking process as it applies to battery chargers and external power 

supplies, and solicit comments, data, and information from participants and other interested 

parties. DOE will also invite comment on its preliminary analyses of battery chargers and 

external power supplies, as described in the draft technical report 

The public meeting will be conducted in an informal, facilitated conference style. There 

shall be no discussion of proprietary information, costs or prices, market shares, or other 

commercial matters regulated by U.S. antitrust laws. A court reporter will record the proceedings 

of the public meeting, which will be entered into the docket for this rulemaking. 

DOE encourages those who wish to participate in the public meeting to read the 

Framework Document and draft technical report and to be prepared to discuss their contents. 

EERE-2008-BT-STD-0005 COMMENT 03
9

Copies of both documents are available at 

www.eere.energy.gov/buildings/appliance_standards/residential/battery_external.html. 

Public meeting participants need not limit their comments to the issues identified in the 

Framework Document. DOE is also interested in receiving comments concerning other relevant 

issues that participants believe would affect any energy conservation standards for these 

products. For example, interested parties are invited to comment on external power supplies not 

included in Class A. DOE is conducting a separate determination analysis rulemaking for these 

products, but intends to invite public comment on the scope of coverage for non-Class A external 

power supplies at the end of the public meeting, if time permits. 

DOE invites all interested parties, whether they participate in the public meeting, to 

submit in writing by [INSERT DATE 45 DAYS AFTER DATE OF PUBLICATION IN 

THE FEDERAL REGISTER], comments and information on matters addressed in the 

Framework Document and on other matters relevant to assessment of energy conservation 

standards for battery chargers and external power supplies. 

After the public meeting and the close of the comment period on the Framework 

Document, DOE will begin collecting data, conducting the analyses as discussed in the 

Framework Document and at the public meeting, and reviewing the comments received. 

EERE-2008-BT-STD-0005 COMMENT 03
10

 DOE considers public participation to be a very important part of the process for setting 

energy conservation standards. DOE encourages the participation and interaction of the public 

during the comment period in each stage of the rulemaking process. Beginning with the 

Framework Document, and during each subsequent public meeting and comment period, 

interactions with and among members of the public provide a balanced discussion of the issues 

that assists DOE in the standards rulemaking process. Accordingly, anyone who would like to 

participate in the public meeting, receive meeting materials, or be added to the DOE mailing list 

to receive future notices and information regarding this and related rulemakings on battery 

chargers and external power supplies should contact Ms. Brenda Edwards at (202) 586-2945, or 

via e-mail at Brenda.Edwards@ee.doe.gov. 

 Issued in Washington, DC, on May 26, 2009. 

 _________________________________ 

 Steven Chalk 

 Principal Deputy Assistant Secretary 

 Energy Efficiency and Renewable Energy 

EERE-2008-BT-STD-0005 COMMENT 03
Energy Conservation Standards 

Rulemaking Framework Document for 

Battery Chargers and External Power Supplies 

U.S. Department of Energy 

Office of Energy Efficiency and Renewable Energy 

Building Technologies Program
 

May 2009 

i 

EERE-2008-BT-STD-0005 COMMENT 03
FOREWORD 

The U.S. Department of Energy (DOE) is publishing this framework document in 

conjunction with a draft technical report that summarizes the preliminary findings of DOE’s 

analysis conducted in 2006 and 2007. This analysis was part of DOE’s Determination Analysis 

for Battery Chargers and External Power Supplies (Docket No. EERE-2006-DET-0136) that the 

Energy Policy Act of 2005 (EPACT 2005) required DOE to perform by August 2008. The 

Energy Independence and Security Act of 2007 (EISA) superseded this determination analysis, 

redefining the scope of the analysis and extending the deadline to December 2009. Among other 

things, EISA also established energy conservation standards for certain types of external power 

supplies, directed DOE to conduct rulemakings to review and consider amending the external 

power supply standards, and required DOE to establish energy conservation standards for battery 

chargers. Given the similarities between these two products and the timing requirements imposed 

by Congress, DOE is bundling these two rulemakings into one proceeding, which together form 

the subject of this framework document. 

While DOE chose in this instance to publish a draft technical report in conjunction with 

this framework document to provide interested parties an opportunity to review and comment on 

the draft analysis prepared in 2006 and 2007, interested parties should not view this action as 

establishing a new precedent for framework document public meetings. Because DOE was 

already examining these products and developing its analysis for the determination analysis 

when EISA altered EPCA, DOE believes that publishing this draft analysis for public review 

now will encourage more detailed and targeted comments from interested parties that will help 

DOE prepare its analysis for the next stage of this rulemaking. 

 Building Technologies Program

 Office of Energy Efficiency and Renewable Energy 

U.S. Department of Energy 

ii 

EERE-2008-BT-STD-0005 COMMENT 03
HOW TO SUBMIT COMMENTS 

DOE seeks comments from the public on this document and any supplemental data or 

other information about battery chargers and external power supplies. The public may submit 

comments, identified by Docket Number EERE-2008-BT-STD-0005 and/or Regulation 

Identifier Number (RIN) 1904-AB57, by any of the following methods: 

	 E-mail: BC&EPS_ECS@ee.doe.gov. Include EERE-2008-BT-STD-0005 and/or RIN 

1904-AB57 in the subject line of the message. 

	 Federal eRulemaking Portal: www.regulations.gov. Follow the instructions for 

submitting comments. 

	 Mail: Ms. Brenda Edwards, U.S. Department of Energy, Building Technologies 

Program, Mailstop EE-2J, Framework Document for Battery Chargers and External 

Power Supplies, EERE-2008-BT-STD-0005 and/or RIN 1904-AB57, 1000 

Independence Avenue, SW., Washington, DC 20585-0121. Please submit one signed 

paper original. 

	 Hand Delivery/Courier: Ms. Brenda Edwards, U.S. Department of Energy, Building 

Technologies Program, 6th Floor, 950 L’Enfant Plaza, SW., Washington, DC 20024. 

Phone: 202-586-2945. Please submit one signed paper original. 

For access to the docket to read background documents, a copy of the transcript of the 

public meeting, or comments received, go to the U.S. Department of Energy, Resource Room of 

the Building Technologies Program, 6th Floor, 950 L’Enfant Plaza, SW., Washington, DC 

20024, between 9 a.m. and 4 p.m., Monday through Friday, except Federal holidays. For more 

information about visiting the Resource Room, contact Ms. Brenda Edwards, 202-586-2945. 

FOR FURTHER INFORMATION CONTACT: 

Mr. Victor Petrolati, U.S. Department of Energy, Office of Energy Efficiency and 

Renewable Energy, Building Technologies, EE-2J, 1000 Independence Avenue, SW., 

Washington, DC 20585-0121. Phone: 202-586-4549. E-mail: Victor.Petrolati@ee.doe.gov. 

Mr. Michael Kido, U.S. Department of Energy, Office of the General Counsel, GC-72, 

1000 Independence Avenue, SW., Washington, DC 20585. Phone: 202-586-9507. E-mail: 

mailto:Michael.Kido@hq.doe.gov. 

For information on how to submit or review public comments and on how to participate 

in the public meeting, contact Ms. Brenda Edwards, U.S. Department of Energy, Office of 

Energy Efficiency and Renewable Energy, Building Technologies Program, EE-2J, 1000 

Independence Avenue, SW., Washington, DC 20585-0121. Phone: 202-586-2945. E-mail: 

Brenda.Edwards@ee.doe.gov. 

iii 

EERE-2008-BT-STD-0005 COMMENT 03
 

TABLE OF CONTENTS 

1 INTRODUCTION .................................................................................................................. 1
 

1.1 The Appliance and Commercial Equipment Standards Program ....................................... 2
 

1.2 Overview of the Rulemaking Process................................................................................. 4
 

1.2.1 Test Procedures.......................................................................................................... 4
 

1.2.2 Rulemaking Process and Interested Party Participation ............................................ 4
 

1.3 Pre-Rulemaking Analyses and Other Activities ................................................................. 6
 

1.4 Notice of Proposed Rulemaking ......................................................................................... 8
 

1.5 Final Rule............................................................................................................................ 9
 

2 OVERVIEW OF ANALYSES FOR RULEMAKING........................................................... 9
 

3 MARKET AND TECHNOLOGY ASSESSMENT ............................................................. 11
 

3.1 Definitions......................................................................................................................... 11
 

3.1.1 Current Statutory Definitions................................................................................... 12
 

3.1.2 Additional Definitions ............................................................................................. 13
 

3.2 Scope of this Rulemaking ................................................................................................. 15
 

3.2.1 Wall Adapters That Do Not Power Battery Charging Systems............................... 16
 

3.2.1.1 Medical EPSs..................................................................................................... 16
 

3.2.2 Battery Charging Systems Not Powered by Wall Adapters .................................... 17
 

3.2.2.1 DC-Powered Battery Charging Systems............................................................ 18
 

3.2.3 Battery Charging Systems Powered by Wall Adapters ........................................... 18
 

3.2.3.1 Wall Adapters Specifically Excluded from Class A EPS Standards ................. 21
 

3.2.3.2 Key Questions.................................................................................................... 22
 

3.2.3.3 Possible Approaches to Interpreting the Definitions of BCs and EPSs............. 23
 

3.2.3.4 Details of Approach A ....................................................................................... 28
 

3.2.3.5 Details of Approach B ....................................................................................... 30
 

3.2.3.6 Details of Approach C ....................................................................................... 33
 

3.2.3.7 Details of Approach D ....................................................................................... 35
 

3.2.3.8 Summary of the Four Approaches ..................................................................... 37
 

3.2.4 Identification of Wall Adapters ............................................................................... 38
 

3.3 Market Assessment ........................................................................................................... 40
 

3.3.1 Distribution Channels .............................................................................................. 41
 

3.3.2 Shipments................................................................................................................. 42
 

3.3.3 Regulatory and Voluntary Programs ....................................................................... 44
 

3.3.4 Market Failures ........................................................................................................ 44
 

3.4 Technology Assessment.................................................................................................... 44
 

3.4.1 Battery Charger Design............................................................................................ 45
 

3.4.2 External Power Supply Design ................................................................................ 47
 

3.5 Measuring Efficiency........................................................................................................ 49
 

3.5.1 Measuring Battery Charger Efficiency .................................................................... 49
 

3.5.2 Measuring External Power Supply Efficiency......................................................... 50
 

3.6 Product Classes ................................................................................................................. 51
 

3.6.1 Battery Charger Product Classes ............................................................................. 51
 

3.6.2 External Power Supply Product Classes.................................................................. 52
 

3.7 Technology Options for Efficiency Improvement............................................................ 57
 

3.7.1 Battery Charger Technology Options ...................................................................... 57
 

iv 

EERE-2008-BT-STD-0005 COMMENT 03
3.7.2 External Power Supply Technology Options........................................................... 59
 

4 SCREENING ANALYSIS ................................................................................................... 59
 

5 ENGINEERING ANALYSIS............................................................................................... 61
 

5.1 Engineering Analysis Overview ....................................................................................... 61
 

5.2 Representative Product Classes and Units........................................................................ 63
 

5.2.1 Battery Charger Representative Units ..................................................................... 64
 

5.2.2 External Power Supply Representative Units.......................................................... 64
 

5.3 Engineering Analysis Approach ....................................................................................... 65
 

5.4 Proprietary Designs........................................................................................................... 67
 

5.5 Outside Regulatory Changes Affecting the Engineering Analysis................................... 68
 

6 ENERGY USE AND END-USE LOAD CHARACTERIZATION .................................... 68
 

6.1 Battery Charger Energy Use ............................................................................................. 69
 

6.2 External Power Supply Energy Use.................................................................................. 71
 

6.2.1 EPS Usage Profiles .................................................................................................. 71
 

6.2.1.1 EPS Modes and Application States.................................................................... 71
 

6.2.2 EPS Power Consumption by Modes of Operation................................................... 73
 

6.2.3 Calculating EPS Energy Use ................................................................................... 76
 

6.3 Off-Mode Energy Consumption ....................................................................................... 77
 

7 PRODUCT PRICE DETERMINATION ............................................................................. 78
 

8 LIFE-CYCLE COST AND PAYBACK PERIOD ANALYSES ......................................... 80
 

8.1 Life-Cycle Cost and Payback Period Methodology.......................................................... 82
 

8.2 Life-Cycle Cost and Payback Period Inputs ..................................................................... 84
 

8.2.1 Electricity Prices ...................................................................................................... 85
 

8.2.2 Life-Cycle Cost Discount Rates............................................................................... 86
 

8.2.3 BC and EPS Operational Lifetimes ......................................................................... 87
 

9 SHIPMENTS ANALYSIS.................................................................................................... 89
 

9.1 Base Case Forecast ........................................................................................................... 89
 

9.2 Standards Impacts on BC and EPS Shipments ................................................................. 92
 

10 NATIONAL IMPACT ANALYSIS..................................................................................... 93
 

10.1 Inputs to Forecasts ............................................................................................................ 93
 

10.2 Calculation of National Energy Savings........................................................................... 95
 

10.3 Net Present Value ............................................................................................................. 96
 

11 LIFE-CYCLE COST SUBGROUP ANALYSIS ................................................................. 97
 

12 MANUFACTURER IMPACT ANALYSIS......................................................................... 98
 

12.1 Sources of Information for the Manufacturer Impact Analysis........................................ 98
 

12.2 Industry Cash-Flow Analysis............................................................................................ 99
 

12.3 Manufacturer Subgroup Analysis ..................................................................................... 99
 

12.4 Competitive Impacts Analysis ........................................................................................ 100
 

12.5 Cumulative Regulatory Burden ...................................................................................... 100
 

13 UTILITY IMPACT ANALYSIS........................................................................................ 101
 

14 EMPLOYMENT IMPACT ANALYSIS............................................................................ 102
 

15 ENVIRONMENTAL ASSESSMENT ............................................................................... 103
 

16 REGULATORY IMPACT ANALYSIS............................................................................. 106
 

APPENDIX A – EPCA DIRECTIVES REGARDING BATTERY CHARGERS AND 

EXTERNAL POWER SUPPLIES ............................................................................................. 108
 

v 

EERE-2008-BT-STD-0005 COMMENT 03
 

APPENDIX B – DEFINITIONS ................................................................................................ 114
 

APPENDIX C – TEST PROCEDURES..................................................................................... 116
 

APPENDIX D – ENERGY INDEPENDENCE AND SECURITY ACT OF 2007................... 119
 

APPENDIX E – LIST OF ITEMS FOR COMMENT................................................................ 126
 

APPENDIX F – OTHER MANDATORY AND VOLUNTARY ENERGY-EFFICIENCY 

STANDARDS FOR BCEPS....................................................................................................... 131
 

F.1 United States – ENERGY STAR for BC and ENERGY STAR Tier I (V1.1) and Tier II 

(V2.0) for EPS ........................................................................................................................ 131
 

F.2 Australia and New Zealand – Minimum Energy Performance Standards (MEPS) AS/NZS 

4665:2005 ............................................................................................................................... 132
 

F.3 Canada – C381.1 for EPS and C381.2 for BC................................................................ 134
 

F.4 China – China National Institute of Standardization (CNIS) and China Standard 

Certification Center (CSC) Standards..................................................................................... 135
 

F.5 European Union—Code of Conduct on Efficiency of External Power Supplies, EU 

Standby Initiative .................................................................................................................... 136
 

F.6 European Union—Eco-design of Energy-using Products (EuP) Initiative, Directive 

2005/32/EC ............................................................................................................................. 138
 

F.7 EU (Subset of Member Countries)Group for Energy Efficient Appliances............... 140
 

F.8 Israel – SI 4665.2 (AS/NZX 4665.2-2005)..................................................................... 140
 

F.9 Korea – e-Standby Program............................................................................................ 141
 

LIST OF TABLES 

Table 1.1. Rulemaking Schedule for BC and EPS Energy Conservation Standards...................... 6
 

Table 3.1. Treatment of Different Types of Wall Adapters That Power a Battery Charging 

Table 3.2. Treatment of Different Types of Wall Adapters That Power a Battery Charging 

Table 3.3. The Answers to the Key Questions Are Combined to Form Four Distinct Approaches 

Table 3.4. Comparison of the Four Approaches to Interpreting the BC and EPS Definitions 

System Spending on the Answer to the First Key Question......................................................... 22
 

System Depending on the Answer to the Second Key Question.................................................. 23
 

to Dealing with Wall Adapters That Power Battery Charging Systems....................................... 23
 

Against Desirable Characteristics................................................................................................. 37
 

Table 3.5. BC-Powered Applications for Which DOE Has Shipment Data................................. 43
 

Table 3.6. EPS-Powered Applications for Which DOE Has Shipment Data ............................... 43
 

Table 3.7. Battery Charger Product Classes Developed for the Draft Determination Analysis... 52
 

Table 3.8. EISA Efficiency Standards for Class A EPSs ............................................................. 53
 

Table 3.9. ENERGY STAR Version 2.0 Active-Mode EPS Product Classes.............................. 54
 

Table 3.10. ENERGY STAR Version 2.0 No-Load-Mode EPS Product Classes........................ 54
 

Table 3.11. Product Classes Used in the EPS Determination Analysis........................................ 56
 

Table 5.1. Representative Unit Characteristics for Battery Chargers........................................... 64
 

Table 5.2. Representative Unit Characteristics Used for External Power Supplies ..................... 65
 

Table 6.1.Summary of EPS Modes............................................................................................... 72
 

Table 6.2. Usage and Output Power of 40W EPS for Inkjet Computer Printer ........................... 73
 

Table 7.1. BC Manufacturer-to-Consumer Markups.................................................................... 79
 

Table 7.2. EPS Manufacturer-to-Consumer Markups .................................................................. 80
 

Table 8.1. Draft Inputs to the Life-Cycle Cost and Payback Period Analyses............................. 85
 

vi 

EERE-2008-BT-STD-0005 COMMENT 03
Table 8.2. Shares and Interest or Return Rates Used for Household Debt and Equity Types...... 87
 

Table 9.3. Base Case Distribution of BC Shipments Across Efficiency Levels by Product Group 

Table 9.4. Base Case Distribution of EPS Shipments Across Efficiency Levels by Product Group 

Table F.1. U.S. ENERGY STAR Tier II for EPS Active-Mode Efficiency and No-Load Power: 

Table F.2. U.S. ENERGY STAR Tier II for EPS Active-Mode Efficiency and No-Load Power: 

Table F.4. Australia/New Zealand MEPS Levels for EPS Active-Mode Efficiency and No-Load 

Table F.5. Australia/New Zealand High Efficiency Level IV for EPS Active-Mode Efficiency 

Table F.6. Australia/New Zealand High Efficiency Level V for EPS Active-Mode Efficiency and 

Table F.8. CSC Levels for Active-Mode Efficiency and No-Load Power (Same as ENERGY 

Table F.9. EU Code of Conduct Version 2 Standards for EPS Active-Mode Efficiency and NoTable F.10. EU Code of Conduct Version 3 Standards for EPSs Excluding Cellular Telephone 

Table F.11. EU Code of Conduct Version 3 Standards for Cellular Telephone Adapters with 

Table F.14. GEEA Levels for EPS and “Portable Personal Equipment” Active-Mode Efficiency 

Table 8.3. Shipment-Weighted Average Lifetimes for Battery Chargers .................................... 88
 

Table 8.4. Shipment-Weighted Average Lifetimes for External Power Supplies ........................ 88
 

Table 9.1. Battery Charger Shipments by Product Group in 2007 ............................................... 90
 

Table 9.2. External Power Supply Shipments by Product Group in 2007.................................... 90
 

in 2007 .......................................................................................................................................... 90
 

in 2007 .......................................................................................................................................... 91
 

Table 9.5. Base Case Shipments Growth Rates for BCs and EPSs .............................................. 92
 

Table 10.1. Inputs to the National Impact Analysis...................................................................... 95
 

Table 12.1 National and International Voluntary and Regulatory Programs for BCs and EPSs 101
 

Standard Models ......................................................................................................................... 131
 

Low-Voltage Models .................................................................................................................. 132
 

Table F.3. ENERGY STAR Specifications for BC Maximum Nonactive Energy Ratio........... 132
 

Power .......................................................................................................................................... 133
 

and No-Load Power .................................................................................................................... 134
 

No-Load Power........................................................................................................................... 134
 

Table F.7. CNIS MEPS for Active-Mode Efficiency and No-Load Power................................ 136
 

STAR Tier 1) .............................................................................................................................. 136
 

Load Power ................................................................................................................................. 137
 

Adapters with Nameplate Output Power ≤ 8 Watts.................................................................... 138
 

Nameplate Output Power ≤ 8 Watts ........................................................................................... 138
 

Table F.12. EuP Version 1 Levels for EPS Active-Mode Efficiency and No-Load Power ....... 139
 

Table F.13. Version 2 Levels for EPS Active-Mode Efficiency and No-Load Power............... 139
 

and No-Load Power .................................................................................................................... 140
 

Table F.15. SI 4665.2 Levels for EPS Active-Mode Efficiency and No-Load Power............... 141
 

Table F.16. e-Standby Program Levels for EPS Active-Mode Efficiency and No-Load Power 142
 

Table F.17. e-Standby Program Levels for Cellular Telephone Charger No-Load Power......... 142
 

LIST OF FIGURES 

Figure 2.1. Analyses Conducted for an Energy Conservation Standard Rulemaking.................. 10
 

Figure 3.1 Example of a Wall Adapter and a Desktop Adapter, Treated Together as “Wall 

Adapters” ...................................................................................................................................... 13
 

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EERE-2008-BT-STD-0005 COMMENT 03
Figure 3.2 Example of a Cradle and a Charging Base................................................................. 14
 

Figure 3.4. Examples of the Three Categories of Products DOE is Considering for Inclusion in 

Figure 3.6. Charge Control Circuitry Required for Battery Charging Can Be Contained in (a) the 

Figure 3.7. The Same Wall Adapter Can Be Used for Both BC and EPS Functions, Depending 

Figure 3.8. Configurations of Power Conversion and Battery Charging Functions in Consumer 

Figure 3.9. Configurations of Power Conversion and Battery Charging Functions in Consumer 

Figure 3.10. Comparison of How Various Battery Charging Systems Would Be Treated Under 

Each of the Four Approaches. The charge control function can be split between enclosures. 

Enclosures covered by the “overlap” would be considered to be subject to both BC and EPS 

Figure 3.11. EPA ENERGY STAR Division Between Products Qualifying Under the EPS and 

Figure 3.3 Examples of Batteries.................................................................................................. 14
 

This Rulemaking........................................................................................................................... 15
 

Figure 3.5 Examples of USB ports. .............................................................................................. 18
 

Cradle or Charging Base, or (b) the Wall Adapter ....................................................................... 19
 

on Which Portion of Its Current-Voltage (I–V) Curve It Is Operating......................................... 20
 

Products......................................................................................................................................... 25
 

Products (Continued) .................................................................................................................... 26
 

standards. ...................................................................................................................................... 27
 

BC Specifications. This division is similar to that under consideration in Approach B. ............. 31
 

Figure 3.12. BC and EPS Distribution Networks ......................................................................... 41
 

Figure 6.1. DIY Power Tool Weekly Usage Profile in Hours...................................................... 71
 

Figure 6.2. Example Measurements from an EPS Test Procedure ............................................... 74
 

Figure 6.3. Relationship Between EPS Input Power and Output Power at Five Loading Points. 75
 

Figure 7.1. BC and EPS Distribution Networks ........................................................................... 78
 

Figure 8.1. Flow Diagram of Inputs for the Determination of LCC and PBP.............................. 83
 

Figure 8.2. AEO 2007 Residential Electricity Price Trend Forecast ............................................ 86
 

viii 

EERE-2008-BT-STD-0005 COMMENT 03
 

 

 

 

LIST OF ACRONYMS AND SYMBOLS 

AC alternating current 

A ampere 

Ah ampere-hour 

AEO Annual Energy Outlook 

AHAM Association of Home Appliance Manufacturers 

BC battery charger 

BOM bill of materials 

BT Building Technologies Program 

CAIR Clean Air Interstate Rule 

CAMR Clean Air Mercury Rule 

CBECS Commercial Building Energy Consumption Survey 

CEA Consumer Electronics Association 

CFR Code of Federal Regulations 

CO2 carbon dioxide 

CSL candidate standard level 

DC direct current 

DIY do-it-yourself 

DOE U.S. Department of Energy 

DOJ U.S. Department of Justice 

DTR Draft Technical Report 

EERE Office of Energy Efficiency and Renewable Energy 

EIA Energy Information Administration (DOE) 

EISA Energy Independence and Security Act of 2007 

EPA U.S. Environmental Protection Agency 

EPACT 2005 Energy Policy Act of 2005 

EPCA Energy Policy and Conservation Act of 1975 

EPS external power supply 

FR Federal Register 

GRIM Government Regulatory Impact Model 

Hg mercury 

IC Integrated Circuit 

ImSET Impact of Sector Energy Technologies 

LCC life-cycle cost 

MIA manufacturer impact analysis 

MSP manufacturer selling price 

NEMS National Energy Modeling System 

NES national energy savings 

NIA national impact analysis 

NOPR notice of proposed rulemaking 

NOx nitrogen oxides 

NPV net present value 

OEM original equipment manufacturer 

OMB U.S. Office of Management and Budget 

PFC Power Factor Correction 

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EERE-2008-BT-STD-0005 COMMENT 03
 

PTI Power Tool Institute 

RIA regulatory impact analysis 

SO2 sulfur dioxide 

SWEF shipment weighted energy factor 

TSD technical support document 

TSL trial standard level 

UEC Unit Energy Consumption 

U.S.C. United States Code 

V volt 

W watt 

x 

EERE-2008-BT-STD-0005 COMMENT 03
 

 

 

1 INTRODUCTION 

The U.S. Department of Energy (DOE) Appliance and Commercial Equipment Standards 

Program, within the Office of Energy Efficiency and Renewable Energy’s Building 

Technologies Program (BT), develops and promulgates test procedures and energy conservation 

standards for consumer products and commercial equipment. As a general matter, the process for 

developing standards involves analysis, public notice, and consultation with interested parties. 

Such parties include manufacturers, consumers, energy conservation and environmental 

advocates, State and Federal agencies, and any other groups or individuals with an interest in 

these standards and test procedures. A DOE report to Congress1

 issued on March 4, 2009, 

identifies the rulemakings DOE has scheduled for completion by June 2011, including standards 

for, battery chargers (BCs) and external power supplies (EPSs). The report explains many of the 

techniques that DOE will apply during the rulemaking process to meet this schedule. In February 

2008, DOE submitted a report to Congress2

 on appliance energy-efficiency rulemakings that sets 

forth DOE’s understanding of the new requirements under the Energy Independence and 

Security Act of 2007 (EISA). 

This Framework Document describes the procedural and analytical approaches that DOE 

anticipates using to evaluate energy conservation standards for BCs and EPSs. (See section 1.1 

below for a discussion of the statutory authority for this rulemaking.) With this document, DOE 

intends to inform interested parties of the process DOE will follow for the standards rulemaking 

for these products, and to encourage and facilitate input from interested parties during the 

rulemaking. DOE views this document as a starting point for developing standards, and not as a 

definitive statement about any issue to be determined in the rulemaking. 

Section 1 provides an overview of DOE’s rulemaking process and background, and 

context for DOE’s work on BCs and EPSs. Sections 2 through 16 discuss DOE’s proposed 

analyses to fulfill the statutory requirements and guidance for this particular standards 

rulemaking. DOE will conduct separate analyses for BCs and EPSs to determine whether new or 

amended energy conservation standards are technologically feasible and economically justified, 

and would result in significant energy savings. DOE will maintain information about these 

rulemakings on its website, 

www.eere.energy.gov/buildings/appliance_standards/residential/battery_external.html. 

1

 U.S. Department of Energy. Energy Conservation Standards Activities; Submitted Pursuant to Section 141 of the 

Energy Policy Act of 2005 and to the Conference Report (109-275) to the FY 2006 Energy and Water Development 

Appropriations Act. Jan. 31, 2006. Available at www1.eere.energy.gov/buildings/appliance_standards/ 

pdfs/congressional_report_013106.pdf. 

2

 U.S. Department of Energy. Implementation Report: Energy Conservation Standards Activities; Submitted
 

Pursuant to Section 141 of the Energy Policy Act of 2005 & Section 305 of the Energy Independence and Security
 

Act of 2007. February 2008. Available at www1.eere.energy.gov/buildings/appliance_standards/pdfs/
 

congressional_report_0208.pdf. 

1
 

EERE-2008-BT-STD-0005 COMMENT 03
Although DOE seeks comments on all aspects of the material presented in this document, 

specific issues are highlighted in comment boxes. DOE uses these comment boxes to ask 

questions about its proposed approaches for conducting the analyses required for the 

standards rulemaking. Requests for feedback are numbered sequentially throughout the 

document and are repeated in appendix E. 

1.1 The Appliance and Commercial Equipment Standards Program 

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 battery 

chargers and external power supplies 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, 71 FR 71340, on December 8, 2006. 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 notice of public meeting 

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.html. 

Regarding the third requirement, on December 19, 2007, EISA, Pub. L. 110-140, was 

enacted, 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 made several changes to EPCA related to BCs and EPSs. 

First, section 301 of EISA modified some of the definitions pertaining to EPSs. EPACT 

2005 defined an EPS as “an external power supply circuit that is used to convert household 

2
 

EERE-2008-BT-STD-0005 COMMENT 03
electric current into DC current or lower-voltage AC current to operate a consumer product.” (42 

U.S.C. 6291(36)(A)) Section 301 of EISA retained that definition, but created a subset of EPSs 

called Class A External Power Supplies. By the definition introduced by EISA, these devices 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.” (42 U.S.C. 6291(36)(C)(i)) Section 301 of EISA further 

amended EPCA by establishing standards for Class A EPSs, effective July 1, 2008, and directing 

DOE to conduct two successive rulemakings to review, and consider amending, the energy 

conservation standards for EPSs, the first of which is required to be completed by July 1, 2011. 

Second, section 309 of EISA amended section 325(u)(1)(E) of EPCA, instructing DOE to 

issue no later than two years after EISA's enactment a final rule determining whether to issue 

energy conservation standards for external power supplies or classes of external power supplies. 

(42 U.S.C. 6295(u)(1)(E)(i)(I)) However, DOE cannot conduct a determination analysis on 

whether it should issue conservation standards for a product for which standards have already 

been set by Congress in section 301(c) of EISA (i.e., Class A external power supplies). 

Furthermore, section 325(u)(1)(E) of EPCA, as amended by EISA, directs DOE to complete this 

determination analysis ‘‘No later than 2 years after the date of enactment of this subsection.’’ (42 

U.S.C. 6295(u)(1)(E)(I)) This subsection, however, is a result of EPACT, which was signed into 

law on August 8, 2005. Interpreting this subsection strictly as amended by EISA would place the 

determination analysis final rule issue date on August 8, 2007, more than four months prior to 

the passage of EISA. 

To resolve these inconsistencies, DOE interprets the ‘‘date of enactment of this 

subsection’’ (42 U.S.C. 295(u)(1)(E)(I)) as the date of passage of EISA, namely December 19, 

2007. In this context, DOE interprets sections 301 and 309 of EISA jointly as a requirement to 

determine, by December 19, 2009, whether energy conservation standards shall be issued for 

EPSs that are covered, but are not classified as Class A external power supplies. Examples of 

these EPSs include those with nameplate output power greater than 250 watts, those that are able 

to convert to more than one AC or DC output voltage at the same time, and those excluded from 

coverage under Class A External Power Supplies (e.g., medical devices). Section 309 also 

required DOE to issue a final rule prescribing energy conservation standards for BCs, if 

technologically feasible and economically justified, by July 1, 2011. (42 U.S.C. 

6295(u)(1)(E)(i)(II)) 

Finally, section 310 of EISA established definitions for active mode, standby mode, and 

off mode, and directs DOE to amend its existing test procedures for both BCs and EPSs to 

measure the energy consumed in standby mode and off mode. (42 U.S.C. 6295(gg)(2)(B)(i)) 

DOE satisfied this requirement by publishing a final rule that incorporated standby and off mode 

measurement into the DOE test procedure. 74 FR 13318 (March 27, 2009). It also amended the 

definitions of standby mode and off mode to better adapt them to how consumers use battery 

chargers and external power supplies. 

The above discussion summarizes the pertinent legislative and regulatory history for BCs 

and EPSs. It sets the stage for the issues raised in the balance of this framework document, which 

initiates an energy conservation standards rulemaking for BCs and EPSs, to be completed by 

July 1, 2011, as required by EISA. (42 U.S.C. 6295(u)(1)(E)(i)(II) and 42 U.S.C. 

3
 

EERE-2008-BT-STD-0005 COMMENT 03
6295(u)(3)(D)(i)) In this rulemaking, DOE will consider setting new standards for BCs and will 

consider amending existing standards for Class A EPSs, consistent with sections 309 and 301, 

respectively, of EISA. When setting any new standard, DOE will also consider the energy 

consumed in standby mode and off mode for these products consistent with EPCA, as amended 

by section 310 of EISA. See appendix B for the statutory definitions of BCs, EPSs, and Class A 

EPSs. 

1.2 Overview of the Rulemaking Process 

1.2.1 Test Procedures 

EPACT 2005 directed DOE to establish test procedures for BCs and EPSs. DOE 

complied with this requirement by publishing the test procedure final rule, 71 FR 71340, on 

December 8, 2006, which included definitions and test procedures for BCs and EPSs. 

As noted above, EISA further amended EPCA by defining active mode, standby mode, 

and off mode. EISA also directed DOE to amend its existing test procedures for both BCs and 

EPSs to measure the energy consumed in standby and off modes. To comply with this 

requirement, DOE published a notice of proposed rulemaking (NOPR) on August 15, 2008, 73 

FR 48054. In that NOPR, DOE also proposed a new test procedure to help with the 

determination analysis required under section 325(u)(1)(E)(i)(I) of EPCA, as amended by EISA. 

(42 U.S.C. 6295(u)(1)(E)(i)(I)) This test procedure would provide a method for measuring the 

standby mode, off mode, and average efficiency of multiple-voltage EPSs. 

Following a public meeting held on September 12, 2008, and after receiving comments 

from interested parties, DOE published a final rule on March 27, 2009. 74 FR 13318. In the final 

rule, DOE amended its test procedures for BCs and EPSs to include provisions for measuring 

standby-mode and off-mode energy consumption. However, due to the limited time provided by 

EISA and limited resources available prior to the publication of this final rule, DOE was unable 

to address the large number of stakeholder comments received on some of the other aspects of 

the NOPR and decided to defer action on these issues and the incorporation of multiple-voltage 

EPSs to a later rulemaking that will address changes to both the BC and EPS test procedures. 

1.2.2 Rulemaking Process and Interested Party Participation 

When DOE evaluates any new or amended energy conservation standard for “covered 

products,” EPCA, as amended, specifies that any standard DOE prescribes for consumer 

products shall be designed to “achieve the maximum improvement in energy efficiency . . . 

which the Secretary [of Energy] determines is technologically feasible and economically 

justified.” (42 U.S.C. 6295(o)(2)(A)) Moreover, EPCA states that the Secretary may not 

establish an amended standard if such standard will not result in a “significant conservation of 

energy,” or “is not technologically feasible or economically justified.” (42 U.S.C. 6295(o)(3)(B)) 

In determining whether a standard is economically justified, DOE considers, to the greatest 

extent practicable, the following seven factors (42 U.S.C. 6295(o)(2)(B)(i)): 

4
 

EERE-2008-BT-STD-0005 COMMENT 03
 

(1)	 the economic impact of the standard on the manufacturers and on the consumers 

of the products subject to such standard; 

(2)	 the savings in operating costs throughout the estimated average life of the covered 

products in the type (or class) compared to any increase in the price, or in the 

initial charges for, or maintenance expenses of, the covered products which are 

likely to result from the imposition of the standard; 

(3)	 the total projected amount of energy (or, as applicable, water) 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 and water conservation; and 

(7)	 other factors the Secretary considers relevant. 

Additional statutory requirements for prescribing new or amended standards are set forth 

in 42 U.S.C. 6295(o)(1)–(2)(A), (2)(B)(ii)-(iii), and (3)–(5). 

The process for developing new or amended energy conservation standards involves 

analysis, public notice, and consultation with interested parties. Such parties generally include 

manufacturers, consumers, energy conservation and environmental advocates, State and Federal 

agencies, and any other groups or individuals with an interest in energy conservation standards 

and test procedures. DOE considers the participation of interested parties a very important part of 

the rulemaking process. The broad array of interested parties who routinely provide comments 

during this process promotes a balanced discussion of critical information required to conduct 

the standards rulemaking. Accordingly, DOE encourages the participation and interaction of all 

interested parties during the comment period provided at each stage of the rulemaking. 

In conducting the test procedure rulemakings and the energy (and water) conservation 

standards rulemakings, DOE involves interested parties through a variety of means, including 

formal public notifications (i.e., Federal Register notices) and public meetings. As discussed in 

further detail below, the standards rulemaking process involves a preliminary publication of 

analyses on the Department’s website, and two major public notices, which are published in the 

Federal Register. The publication of the preliminary analyses as well as the NOPR will be 

accompanied by public meetings to solicit comment from interested parties to guide the 

rulemaking process. 

	 Preliminary publication of analyses and public meeting (section 1.3): The 

preliminary publication of analyses and public meeting is designed to obtain public 

review of the models and tools that DOE will use in the rulemaking and to facilitate 

public participation before the proposed rule stage. Candidate standard levels (CSLs), 

which span the range of efficiencies from baseline products to the most efficient 

technology, are the basis for demonstrating the functionality of the models and tools.3 

3

 In the past DOE issued an Advance Notice of Proposed Rulemaking (ANOPR) following publication of the 

framework document. The Energy Independence and Security Act of 2007 eliminated the requirement that DOE 

issue ANOPRs as part of the standards rulemaking process, see EISA, at sec. 307. DOE is now using an alternate 

5
 

EERE-2008-BT-STD-0005 COMMENT 03
 

 

 

	 NOPR (section 1.4): The NOPR presents a discussion of comments received in 

response to the preliminary analyses; DOE’s analysis of the impacts of standards on 

consumers, manufacturers, and the nation; DOE’s weighing of those impacts; and the 

proposed standard levels for public comment. 

	 Final rule (section 1.5): The final rule presents a discussion of comments received in 

response to the NOPR, the revised analysis of the impacts of standards, DOE’s 

weighting of the impacts, and the standard levels DOE is adopting. The final rule also 

establishes the effective date of the standards. 

DOE has prepared and intends to follow the schedule below for the BC and EPS energy 

conservation standards rulemaking. 

Table 1.1. Rulemaking Schedule for BC and EPS Energy Conservation Standards 

Rulemaking Notice Publication Date 

Framework Document May 2009 

Preliminary Analyses Public Meeting Notice March 2010 

NOPR December 2010 

Final Rule July 1, 2011 (EISA Deadline) 

Any amended standards for Class A EPSs promulgated by the Final Rule would apply to 

products manufactured on or after July 1, 2013. (42 U.S.C. 6295(u)(3)(D)(i)) A compliance date 

for new BC standards has not yet been established since EISA did not set one. 

1.3 Pre-Rulemaking Analyses and Other Activities 

DOE’s initial pre-rulemaking activity typically includes identifying product technology 

options and determining whether they warrant detailed analysis or can be eliminated from further 

consideration. This process includes a market and technology assessment (section 3) and a 

screening analysis (section 4). DOE applies four criteria in the screening analysis to determine 

which technology options to eliminate from further consideration: technological feasibility; 

practicability to manufacture, install, and service; adverse impacts on product utility or 

availability; and adverse impacts on health or safety. DOE calls technologies that pass the 

screening analysis “design options,” and considers them in the engineering analysis as methods 

of improving the efficiency of the covered products. 

Also in the pre-rulemaking stage of the analysis, DOE collects manufacturer cost data, 

historical shipment data, shipment-weighted average efficiency data, and preliminary 

manufacturer impact data (e.g., capital conversion expenditures, marketing costs, and research 

and development costs). Given these data, and the efficiency levels achievable by the design 

options developed earlier, DOE estimates the impact of potential standards on individual 

process to provide the same information and opportunity for public comment as the ANOPR, but without 

publication of analyses in the Federal Register. 

6 

EERE-2008-BT-STD-0005 COMMENT 03
 

 

consumers and the Nation as a whole. These calculations are contained within the following 

analyses, explained in subsequent sections of this framework document: 

	 the engineering analysis (section 5); 

	 the consumer life-cycle cost (LCC) and payback period (PBP) analyses (section 8); 

	 the national impact analysis, which considers national energy savings (NES) and 

national consumer net present value (NPV) (section 10); and 

	 a preliminary manufacturer impact analysis (section 12). 

DOE will present the results of these analyses in a technical support document (TSD) to 

be published prior to the NOPR stage of the rulemaking. The preliminary TSD, which will be 

made available on the Department’s website, will be followed by a preliminary analyses public 

meeting. A meeting agenda, presentation slides, and an executive summary highlighting the 

issues on which DOE seeks comment will accompany the TSD on the website. DOE will publish 

a notice announcing the availability of the materials and the meeting in the Federal Register. 

Discussion of various CSLs in the preliminary TSD will facilitate review by interested 

parties of the spreadsheet models that underpin the analyses. DOE will use these comments to 

refine the models for the NOPR stage of the rulemaking analyses, where DOE will propose 

specific efficiency levels for adoption. Based on the results, DOE selects CSLs from the energyefficiency or energy-use levels considered in the preliminary analyses. In addition to the 

efficiency levels corresponding to the maximum technologically feasible (“max-tech”)4

 design 

and the minimum LCC point, DOE generally selects for consideration levels or design options 

that span the full range of technologically achievable efficiencies. DOE typically analyzes the 

following CSLs: 

	 the baseline CSL (i.e., the minimum level) is represented by the product with the 

lowest energy-efficiency level currently sold on the market for a given product class; 

for classes where energy-efficiency standards already exist, the baseline efficiency 

level is typically defined by the existing energy conservation standard; 

	 the highest CSL or lowest energy consumption level that is technologically feasible 

(i.e., the “max-tech” level); 

	 the level with the minimum LCC or greatest LCC savings; and 

	 levels that incorporate noteworthy technologies or fill in large gaps between other 

CSLs considered. 

In the preliminary analyses DOE uses analytical models and tools to assess the different 

product classes at each efficiency or energy use level analyzed. Many of these analytical models 

and tools are in the form of spreadsheets, some of which DOE uses to conduct the LCC and PBP 

analyses and to determine the NES and NPV of prospective standards. Preliminary results may 

4

 The “max tech” 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. 

7
 

EERE-2008-BT-STD-0005 COMMENT 03
 

 

facilitate discussions among interested parties on potential joint recommendations for standard 

levels. 

In addition to the other materials mentioned above, DOE will make the spreadsheet tools 

used for the preliminary analyses available on its website for review and will consider comments 

after the public meeting.5 DOE will provide a 60-day public comment period following the 

publication of the preliminary analyses notice. At that point, DOE encourages interested parties 

to develop joint recommendations for standard levels to the extent possible. 

1.4 Notice of Proposed Rulemaking 

In developing the NOPR, DOE will first review and consider all the comments it receives 

after the public meeting. This process may result in revisions or refinements to the preliminary 

analyses, including the engineering and LCC analyses. DOE will also conduct additional 

economic and environmental impact analyses at this stage of the rulemaking. These analyses 

generally include a consumer LCC subgroup analysis (section 11), a complete manufacturer 

impact analysis (section 12), a utility impact analysis (section 13), an employment impact 

analysis (section 14), an environmental assessment (section 15), and a regulatory impact analysis 

(section 16). 

DOE will describe the methodology used and make the results of all the analyses 

available on its website for review and comments. Based on comments from interested parties, 

DOE may further revise the analyses. This analytical process ends with the selection of a 

proposed standard level (if any) for each product class that DOE will present in the NOPR. DOE 

selects the proposed standard levels from the trial standard levels (TSLs) analyzed during the 

NOPR phase of the rulemaking, equivalent to the CSLs analyzed during the preliminary 

analyses. The NOPR, published in the Federal Register, will document the evaluation and 

selection of any proposed standards levels, along with a discussion of other TSLs considered but 

not selected, including the reasons for not selecting them. 

In selecting proposed efficiency standards, DOE generally first identifies the max-tech 

efficiency level. If DOE proposes a level lower than that, it will explain sequentially the reasons 

for eliminating each higher level, beginning with the highest level considered. DOE will present 

the analytical results in the NOPR, with the details of the analysis provided in an accompanying 

TSD. 

DOE considers many factors in selecting proposed standards, as described above in 

section 1.3. These factors and the associated criteria are specified in EPCA and consider the 

benefits, costs, and impacts of energy conservation standards. Additionally, DOE encourages 

interested parties to develop joint recommendations for standard levels. DOE will carefully 

consider such recommendations in its decision process. 

When DOE publishes the NOPR, it will provide the Department of Justice (DOJ) with 

copies of the NOPR and TSD to solicit feedback on the impact on competition that the proposed 

5 All materials associated with the battery chargers and external power supplies rulemakings are available on DOE’s 

website at www1.eere.energy.gov/buildings/appliance_standards/residential/battery_external.html. 

8
 

EERE-2008-BT-STD-0005 COMMENT 03
standard levels would have. DOJ will review these standard levels in light of any lessening of 

competition that is likely to result from the imposition of standards. (42 U.S.C. 

6295(o)(2)(B)(i)(V) and (B)(ii)) Publication of the NOPR will be followed by a public meeting 

and a 60-day public comment period. 

1.5 Final Rule 

After the publication of the NOPR, DOE will consider public comments that it receives 

on the proposal (including TSLs) and accompanying analyses. On the basis of the public 

comments, DOE will review the engineering and economic impact analyses and proposed 

standards and consider modifications where necessary. Before issuing the final rule, DOE will 

also consider DOJ comments on the impacts of the proposed standard levels on competition to 

determine whether changes to these standard levels are needed. 

The standards rulemaking will conclude with the publication of the final rule. DOE will 

select the final standard level based on the complete record of the standards rulemaking. The 

final rule will specify the final standard level and its effective date and explain the basis for the 

selection. The final rule will be accompanied by a final TSD. 

2 OVERVIEW OF ANALYSES FOR RULEMAKING 

Analyses are conducted in support of the standards rulemaking to ensure that DOE 

selects energy conservation standards that achieve the maximum improvement in energy 

efficiency that is technologically feasible and economically justified, and will result in 

significant energy savings. Economic justification includes the consideration of economic 

impacts on domestic manufacturers and consumers, national benefits including environmental 

impacts, issues of consumer utility, and impacts from any lessening of competition. DOE expects 

the selection of such standards to achieve the maximum energy savings that are economically 

justified without imposing an undue financial burden on any particular party. 

Figure 2.1 summarizes the analytical components of the standards-setting process. The 

analyses are presented in the center column. Each analysis has a set of key inputs, which are data 

and information required for the analysis. The identified approaches are the methods that DOE 

will use to obtain key inputs, which may vary depending on the information in question. DOE 

will collect other information from interested parties or experts with special knowledge and 

develop analyses and other information in support of this rulemaking. The results of each 

analysis are key outputs, which feed directly into the rulemaking. Arrows indicate the flow of 

information among the various analyses. DOE ensures a consistent approach to its analyses 

throughout the rulemaking by considering each analysis as a part of the overall standards-setting 

framework. DOE intends to conduct each of these analyses separately for BCs and EPSs. 

9
 

EERE-2008-BT-STD-0005 COMMENT 03
Approaches Key Inputs Analyses Key Outputs 

Framework Document ork Document 

• Characterize Industry

• Analysis of Market Data 

• Market Segmentation 

• Non-Regulatory Programs 

• Identify Firms/Products

• Historical Shipments Market anMarket and Technology 

Assessment 

• Product Classes 

• Technology Options 

• Efficiency-Level Approach 

• Design Option Approach 

• Accounting Approach 

• BackcastBackcast and Forecast

• Market Saturation 

•Retail Price Collection and

Analysis

• Analysis of Energy Use 

Data 

• Analysis of Product Data 

 

 

 

ScreeninScreening Analysis 

Engineering Analysis 

Product Price 

Determination Life-Cycle Cost and

Payback Periack Period

Analyses 

National Impact 

Analysis 

Energy Use 

Shipments Shipments 

Analysis 

• Product Designs 

• Life-Cycle Costs

• Payback Periods 

• National Energy Savings 

• Net Present Values 

• Energy Prices 

• Installation Costs 

• Maintenance & Repair Costs 

Design Options 

Product Classes 

Retail 

Prices 

Design Energy/ Use 

• Efficiency/Performance 

• Commercial Products 

Candidate 

Standard 

Levels 

Technology Options 

• Design Options 

• Energy Price Forecasts 

• Site-to-Source Factors 

• Energy-Efficiency Levels • InstallatiInstallation 

Costs 

• Maint Costs 

• Repair Costs 

• UEC 

• Energy Prices 

Annual Energy Use (UEC) 

PreliminarPreliminary

Manufacturer Impact

Analysis 

• Manufacturer Prices 

• Average Costs 

• Conversion Capital Expenditures 

• Direct Emplect Employment Impacts 

• Product Prototypes 

Energy-Efficiency

Levels Product Designs 

Advance Notice of Proposed Rulemaking (ANO) Publication of Preliminary Analyses 

 

 

• Manufacturer Interviews 

• GRIM Analysis

• NEMS-BT 

• ImSET 

• Stakeholder Comments 

• Demographics 

• Manufacturer Prices 

• Average Costs 

• Manufacturer Financial Data 

• Utility Load Factors Load Factors 

• National Energy Savings 

• National Energy Savings 

• National Product Costs 

• National Operating Costs 

Revise Preliminary

Utility Impact 

Analysis 

Analyses 

Life-Cycle Cost

Sub-Group Analysis 

Manufacturer Impact

Analysis 

Employment Impact 

Analysis 

TSLs 

 

 

• Industry Cash Flow

• Sub-Group Cash-Flow 

• Direct Emplect Employment Impacts 

• Competitive Impacts 

• Cumulative Regulatory Burden 

• National Employment Impacts 

Direct Emplect Employment

Impacts 

• Utility Impacts 

• Life-Cycle Costs

• Payback Periods 

• Trial Standard Levels (TSLs) 

• NEMS-BT 

• Emission Rates 

• National Energy Savings Environmentalronmental 

Assessment • Emission Estimates 

• Non-Regulatory 

Alternatives Regulatory Impact 

Analysis 

• National Energy Savings 

• Net Present Values 

Notice of Prce of Proposed Rulemaking (NOPR) ng (NOPR) 

• Stakeholder Comments 

• Department of Justice Review 

Revise Analyses • Revised Results 

Final Rule 

Figure 2.1. Analyses Conducted for an Energy Conservation Standard Rulemaking 

10

EERE-2008-BT-STD-0005 COMMENT 03
Before the enactment of EISA, DOE was working to determine whether it should set 

standards for BCs and EPSs, as required by EPACT 2005. In a separate draft technical report 

published in conjunction with this framework document, DOE presents the determination 

analysis that it had been developing for BCs and EPSs. DOE invites interested parties to review 

the draft technical report and provide comments to DOE on all aspects of the draft analysis 

pertaining to the energy conservation standards rulemaking initiated by this framework 

document. All the major issues associated with the analysis presented in the draft technical report 

are identified for comment by “Item” boxes throughout this framework document. The draft 

technical report provides more detail on these issues by characterizing DOE’s current 

understanding of the technology and market for BCs and EPSs, as well as the inputs and methods 

DOE proposes to use in its future analyses. 

DOE developed the draft technical report, which is being made available in conjunction 

with this framework document, as part of the determination analysis on BCs and EPSs DOE is 

conducting under EPACT 2005. That determination analysis, however, was superseded by EISA, 

which modified its scope and schedule and initiated rulemakings to consider new and amended 

standards for BCs and EPSs, respectively. The publication of the draft technical report, therefore, 

represents a special case, and should not be construed as setting a precedent for future DOE 

action in conjunction with the publication of a framework document. 

Item 1 DOE invites interested parties to review the draft technical report published 

in conjunction with this framework document and to provide comments on the analytical 

structure, inputs, and method DOE followed. 

3 MARKET AND TECHNOLOGY ASSESSMENT 

The market and technology assessment will provide information about BC and EPS 

manufacturers and specifics about the performance attributes of BCs and EPSs. This assessment 

is particularly important at the outset of the rulemaking for developing product classes and 

identifying technology options that improve the efficiency of BCs and EPSs. 

3.1 Definitions 

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. 

11
 

EERE-2008-BT-STD-0005 COMMENT 03
 

3.1.1 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.”6

 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. The relevant portions of these acts follow: 

Battery Charger 

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)) 

External Power Supply 

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)) 

Class A External Power Supply 

i. IN GENERAL- The term class A external power supply means a device that— 

I.	 is designed to convert line voltage AC input into lower voltage AC or DC 

output; 

II.	 is able to convert to only 1 AC or DC output voltage at a time; 

III.	 is sold with, or intended to be used with, a separate end-use product that 

constitutes the primary load; 

IV.	 is contained in a separate physical enclosure from the end-use product; 

V.	 is connected to the end-use product via a removable or hard-wired male/female 

electrical connection, cable, cord, or other wiring; and 

VI.	 has nameplate output power that is less than or equal to 250 watts. 

ii.	 EXCLUSIONS- The term class A external power supply 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)) 

Consumer Product 

The term consumer product means any article (other than an automobile, as defined in 

section 32901 (a)(3) of title 49) of a type— 

A. which in operation consumes, or is designed to consume, energy or water with respect 

to showerheads, faucets, water closets, and urinals; and 

B. which, to any significant extent, is distributed in commerce for personal use or 

consumption by individuals without regard to whether such article of such type is in 

fact distributed in commerce for personal use or consumption by an individual, except 

6

 This part was originally titled Part B but it was redesignated Part A in the United States Code for editorial reasons. 

12
 

EERE-2008-BT-STD-0005 COMMENT 03
 

 

that such term includes fluorescent lamp ballasts, general service fluorescent lamps, 

incandescent reflector lamps, showerheads, faucets, water closets, and urinals 

distributed in commerce for personal or commercial use or consumption. (42 U.S.C. 

6291(1)) 

Detachable Battery 

The term detachable battery means a battery that is— 

A. contained in a separate enclosure from the product; and 

B. intended to be removed or disconnected from the product for recharging. (42 U.S.C. 

6291(52)) 

3.1.2 Additional Definitions 

The following additional terms are used by DOE throughout this framework document to 

provide clarification and further describe components of BCs and EPSs: 

 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). 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.7 

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 allow an observer to determine the internal 

circuitry (and the corresponding functions) of a wall adapter. Furthermore, some adapters can 

provide different functions depending on their region of operation—i.e., the output current and 

voltage at a particular time. 

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 3.2). 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 

7

 A transformer within the adapter—which also serves to reduce the voltage level from the mains voltage of 

120 V AC—passes power while blocking the direct electrical path between input and output. 

13
 

EERE-2008-BT-STD-0005 COMMENT 03
no distinguishing physical features that would allow an observer to conclusively determine their 

internal circuitry and function. 

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 

Item 2 DOE welcomes comment from interested parties on differentiating between 

wall adapters and cradles. DOE also seeks comment on the type of circuitry (or lack 

thereof) typically contained in cradles. 

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 non-standard, 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. 

Laptop battery Power tool battery pack Standard-size batteries 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. 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. In 

the following discussion, care has been taken to distinguish between these regulatory and 

physical terms. 

14
 

EERE-2008-BT-STD-0005 COMMENT 03
 

 

 

3.2 Scope of this Rulemaking 

EPCA, as amended by EISA, requires DOE to conduct this standards rulemaking on BCs 

and Class A EPSs. However, the statutory definitions of these two terms leave substantial room 

for interpretation. Comments received from interested parties during the public meeting on the 

standby and off mode test procedure NOPR on September 12, 2008, emphasized that many 

interested parties were unsure how to classify their products. Specifically, because wall adapters 

are sometimes used with battery charging systems and because the definitions of BCs and EPSs 

are not mutually exclusive, it is unclear which portions of the system fall under the EPS and BC 

definitions, respectively. 

To be clear, when a wall adapter meeting the EPS definition powers any application other 

than a battery charging system, DOE considers that device to be an EPS. Similarly, in cases 

where a battery charging system meets the BC definition, and does not use a wall adapter, DOE 

considers the entirety of the system to be a BC. Only in cases when a wall adapter powers a 

battery charging system is the situation ambiguous. These three cases are illustrated in Figure 

3.4. 

Category 

Wall adapter not 

powering a battery 

charging system 

(considered an EPS) 

Example (a) Computer monitor 

with wall adapter 

Battery charging not 

powered by a wall 

adapter (considered a 

BC) 

(b) Universal charger for 

AA batteries 

Unclear how DOE should 

consider the wall adapter 

and battery charging 

system components 

(c) Cell phone with wall 

adapter and battery 

Illustration 

Figure 3.4. Examples of the Three Categories of Products DOE is Considering for 

Inclusion in This Rulemaking 

How DOE interprets this term will affect both this rulemaking and the scope of other 

rulemakings underway for BCs and EPSs described earlier in section 1. More immediately, 

DOE’s interpretation of Class A EPS will also affect which wall adapters are subject to the EISA 

Class A EPS standards that became effective on July 1, 2008. The following subsections will 

discuss possible interpretations of the BC and EPS definitions and the impact of these 

interpretations on energy conservation standards.8 

8

 DOE outlined an interim approach to differentiating BCs and EPSs at the Scoping Workshop Public Meeting on 

Developing Energy Conservation Standards for BCEPS, on January 24, 2007. At that time, DOE indicated that it 

might review and revise this approach as well as consider whether devices serving both BC and EPS functions 

should be subject to both standards. The following subsections are intended to present this revision. 

15
 

EERE-2008-BT-STD-0005 COMMENT 03
 

3.2.1	 Wall Adapters That Do Not Power Battery Charging Systems 

As mentioned above, DOE considers wall adapters that meet the EPS definition and that 

do not power a battery charging system to be EPSs. Furthermore, based on the EISA definition 

for Class A EPS (42 U.S.C. 6291(36)(C)), DOE considers a wall adapter that meets the 

following conditions to fall within the scope of this rulemaking: 

(1)	 Able to convert to only one AC or DC output voltage at a time; 

(2)	 Has nameplate output power that is less than or equal to 250 watts; and 

(3)	 Does not power: 

i.	 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; or 

ii.	 the charger of a detachable battery pack or charges the battery of a 

product that is fully or primarily motor operated. 

EPSs excluded from the Class-A EPS definition (42 U.S.C. 6291(36)(C)) are not within the 

scope of this rulemaking, and will be covered in a separate rulemaking on non-Class A EPSs, as 

required by EISA. (42 U.S.C. 6295(u)(1)(E)(i)(I)) That separate rulemaking will determine 

whether energy conservation standards shall be issued for four types of 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)	 EPSs for Particular Battery Charging Applications: These devices provide power 

to battery chargers of detachable batteries or batteries of products that are motor 

operated. The devices included in this type are heavily dependent on the 

interpretation of the BC and EPS definitions chosen by DOE, as discussed in 

section 3.2.3.1. 

While the first two types of non-Class A EPSs are easily understood, the exclusions for 

EPSs that power medical devices and particular battery charging applications are more nuanced. 

The former is explained in section 3.2.1.1, the latter, in section 3.2.3.1. 

3.2.1.1 Medical EPSs 

The definition of Class A EPS excludes, in relevant part, “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).” (42 U.S.C. 

6291(36)(C)(ii)(I)) While this language may appear clear on its face, it raises a number of 

interpretive issues. 

First, it is unclear whether the exclusion should apply only to EPSs that are themselves 

listed as medical devices or also to EPSs that are components of listed medical devices. A literal 

16
 

EERE-2008-BT-STD-0005 COMMENT 03
 

reading of EPCA would exclude from Class A only those EPSs that are themselves medical 

devices. A search of the Food and Drug Administration’s (FDA) product classification database 

for “power supply,” however, shows that of the approximately 1,700 types of medical devices, 

only one device might be an EPS—an auxiliary power supply (ac or dc) for an external 

transcutaneous cardiac pacemaker. 

However, there are several other types of medical devices that may have EPSs as 

components, for example, nebulizers and sleep therapy devices. These medical devices are 

tested, listed, and approved for use with specific EPSs, which must meet the safety standards 

codified in International Electrotechnical Commission (IEC) Standard 60601-1. Furthermore, 

once the medical device has been approved for use with the EPS, the EPS is not interchangeable 

and can be considered an integral part of the medical device. Thus, DOE interprets EPCA to also 

exclude from Class A those EPSs that power medical devices. 

Second, the exclusion applies to devices that are required to be listed and approved under 

21 U.S.C. 360c. Section 360c creates three classes of medical devices (Classes I through III), all 

of which are subject to the listing requirements of FDA regulations. Similarly, each class 

requires some level of approval by FDA, ranging from the filing of forms with the agency (such 

as 510(k) approval filings) to premarket approvals for devices intended for human use (as occurs 

with Class III medical devices, which pose a higher degree of risk to users). 9 

Each device covered under Section 513 requires regulatory oversight by the FDA because 

of its impact on the public health. Since these devices play a vital role in helping to ensure public 

health, DOE believes that the exclusion created by Congress was designed to prevent any 

adverse impact on the public with respect to the safety of these regulated devices. This concern is 

highlighted by DOE’s obligation under EPCA to consider the performance of a regulated product 

when subjected to a new standard, as well as other factors that the agency considers relevant— 

such as the health and safety of the public, which could be put at risk by imposing limits on 

energy usage. (42 U.S.C. 6295(o)(IV) and (VII)) 

Accordingly, given the language provided by Congress with respect to this exclusion and 

the criteria set out under EPCA, DOE believes that under the most reasonable interpretation, this 

exclusion applies to all EPSs that are Class I, II, and III medical devices or that are components 

of such devices. 

Item 3 DOE requests comment from interested parties on its interpretation of the 

Class A EPS exclusion of medical EPSs. 

3.2.2 Battery Charging Systems Not Powered by Wall Adapters 

According to its statutory definition, a BC is “a device that charges batteries for 

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

U.S.C. 6291(32)) DOE considers all components of a system that meet this definition—but not 

9

 “Classify Your Medical Device,” Center for Devices and Radiological Health, U.S. Food and Drug 

Administration. www.fda.gov/cdrh/devadvice/313.html. 

17
 

EERE-2008-BT-STD-0005 COMMENT 03
necessarily the wall adapter, discussed further in section 3.2.3—to be within the scope of this 

rulemaking on BCs and Class A EPSs. 

3.2.2.1 DC-Powered Battery Charging Systems 

DOE also intends to include within this rulemaking battery charging systems that draw 

power from DC sources other than wall adapters. These DC sources include, for example, 

computer universal serial bus (USB) ports and automobile cigarette lighter receptacles. DOE 

believes these BCs are within the scope of the rulemaking because the BC definition—unlike the 

EPS definition—does not specify that the device input power must be AC. Furthermore, these 

BCs are a type of product “other than an automobile . . . which in operation consumes, or is 

designed to consume, energy”—i.e., “electricity, or fossil fuels.” (42 U.S.C. 6291(1) and (3)) 

A potential complication with including DC-powered chargers arises in the case of wall 

adapters with a USB output, as shown in Figure 3.5(b). A USB-powered charger embedded in a 

portable device can draw power from either a computer (Figure 3.5(a)) or one of these wall 

adapters. However, the USB output of this adapter could not only power a battery charger 

embedded in, for example, a portable music player, but also a consumer product without a 

battery. If the USB wall adapter is not designed for a specific battery charging system, but is sold 

as an after-market accessory, DOE proposes to treat it as a wall adapter that does not power a 

battery charging system (i.e., an EPS). If, however, it is packaged and sold together with a 

battery charging system, DOE proposes to treat it as a wall adapter for that system, according to 

one of the approaches presented in section 3.2.3. 

(a) USB port on a laptop (b) USB port on a wall 

computer adapter 

Figure 3.5 Examples of USB ports. 

Item 4 DOE seeks comments on including DC-powered battery chargers within the 

scope of the BC standards analysis. 

3.2.3 Battery Charging Systems Powered by Wall Adapters 

The current definitions for BCs and EPSs are not mutually exclusive. This fact becomes 

problematic when wall adapters (which can be considered EPSs) are a part of battery charging 

systems. While some of these wall adapters are electrically equivalent to wall adapters that 

power non-battery charging applications, others operate differently by providing additional 

functions necessary for battery charging. 

18
 

EERE-2008-BT-STD-0005 COMMENT 03
These additional functions include current and temperature sensing, timing, and current 

limiting, all of which are included in battery charging systems for safety reasons. When 

manufacturers decide to use a wall adapter to perform the power conversion for a battery 

charging system, they may also shift some of these charge control functions to the wall adapter, 

as illustrated in Figure 3.6. 

Figure 3.6. Charge Control Circuitry Required for Battery Charging Can Be Contained in 

(a) the Cradle or Charging Base, or (b) the Wall Adapter 

Wall adapter constant-voltage (CV) sources perform only AC/DC conversion functions, 

converting mains power at 120 volts AC to low-voltage DC power suitable for the safe operation 

of electronic products. Constant-voltage sources provide a fixed voltage regardless of the current 

drawn by the end-use product load (as long as the current remains within the specified region of 

operation and given some imperfections due to regulation—i.e., the dependence of output 

voltage on load current). 

Wall adapter constant-current (CC) sources also operate at low DC voltages; however, 

their output characteristics are opposite those of constant-voltage sources. Rather than provide a 

fixed voltage regardless of the current, they provide a fixed current, regardless of the load 

voltage. The latter characteristic is necessary in battery charging applications to limit charging 

current into the battery—as the battery voltage varies from fully discharged to fully charged, the 

constant-current source will maintain the charge current at a safe level and prevent overheating 

of the battery. 

Referring again to Figure 3.7, it is possible to see how the constant-current and constantvoltage sources are combined in a typical charger design for lithium-ion or lead-acid batteries. 

The wall adapter will act as a constant-current or constant-voltage source depending on its region 

of operation. When the battery is discharged and its voltage is low (see the bottom portion of 

Figure 3.7), the charger operates as a constant-current source, limiting the charge current flowing 

into the battery. However, when the battery is charged and its voltage is high (see the top portion 

of Figure 3.7), the charger operates as a constant-voltage source, outputting a fixed voltage and 

maintaining full charge. 

19
 

EERE-2008-BT-STD-0005 COMMENT 03
Figure 3.7. The Same Wall Adapter Can Be Used for Both BC and EPS Functions, 

Depending on Which Portion of Its Current-Voltage (I–V) Curve It Is Operating 

In other words, some wall adapters used in a battery charging system may do more than 

“convert household electric current into DC current or lower-voltage AC current”—the role of an 

EPS, according to the EPACT 2005 definition. (42 U.S.C. 6291(36)(A)) These additional charge 

control functions may add to the cost and power consumption of the wall adapter, and may even 

make it functionally unsuitable for use with other, non-battery charging applications. 

Once the EPS definition has been interpreted to either include or exclude wall adapters, 

DOE must then interpret the BC definition, which is also ambiguous. Specifically, the BC 

definition does not specify the input power source for the battery charger. As a result, in cases 

such as the one illustrated in Figure 3.6(a), where the wall adapter only performs power 

conversion and no battery charging functions, it is unclear whether to consider the entire battery 

charging system (i.e., from AC mains to the battery) as the BC, or only the components 

downstream from the wall adapter (i.e., from the charging base to the battery). 

The interpretation of the BC definition, like the EPS definition, depends on the 

functionality of the wall adapter. If a wall adapter provides charge control, the battery charging 

system it powers cannot operate or be tested without it. On the other hand, if the wall adapter 

only provides power conversion, it can be modeled as a voltage source, and the battery charging 

system can be tested independently of the wall adapter. In this case, the wall adapter portion of 

the battery charging system could therefore be included or not included in the eventual BC 

standards. 

20
 

EERE-2008-BT-STD-0005 COMMENT 03
 

3.2.3.1 Wall Adapters Specifically Excluded from Class A EPS Standards 

The above discussion concerns battery charging functionality, and its use as a 

determinant for inclusion of wall adapters within the scope of BC and EPS standards. However, 

though a particular wall adapter may be considered an EPS based on its lack of charge control 

functionality, it may still be excluded from this rulemaking because the Class A definition 

presented in section 3.2.1 excludes EPSs used within specific kinds of battery charging systems. 

In particular, 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” is excluded. (42 U.S.C. 6291 

(36)(C)(ii)(II)) EISA further defines a detachable battery as one that is “(A) contained in a 

separate enclosure from the product; and (B) intended to be removed or disconnected from the 

product for recharging.” (42 U.S.C. 6291(52)) 

The second criterion in paragraph (36)(C)(ii)(II) is clear: any wall adapter that falls under 

the definition of EPS is excluded from current and future Class A EPS standards if it is part of a 

battery charging system used with a power tool or other motor-operated rechargeable product. 

The meaning of the first criterion in paragraph (36)(C)(ii)(II) is less clear. The phrase 

“contained in a separate enclosure from the product,” however, appears earlier in the Class A 

EPS definition, providing a potential interpretation. In that case, the definition limits Class A 

EPSs to devices “contained in a separate physical enclosure from the end-use product,” i.e., a 

separate component outside the physical boundaries of the end-use consumer product. (42 U.S.C. 

6291(36)(C)(i)(IV)) 

Similarly, when applied to detachable batteries, this phrase can also be interpreted to 

mean “wholly outside the physical boundaries of the end-use consumer product.” This is in 

contrast to batteries contained in an enclosure wholly or partly inside the physical boundaries of 

the end-use consumer product (e.g., inside a battery compartment). 

A further constraint on the definition of detachable batteries is the requirement that they 

be “intended to be removed or disconnected from the product for recharging.” (42 U.S.C. 

6291(52)(B)) Thus, even if a battery is not contained inside the product, it may not be considered 

“detachable” unless it is also intended to be “removed or disconnected from the product.” 

In particular, several popular models of camcorders employ wall adapters that can be 

used to power the camcorder and charge its battery.10 However, even though these batteries are 

not contained inside the product, it is not necessary to remove them for charging. Rather, the 

wall adapter plugs directly into the camcorder body or into a cradle that accepts the entire 

camcorder. Therefore, DOE does not consider these batteries detachable and does not consider 

the wall adapters for these camcorders to be excluded from the Class A EPS definition per 42 

U.S.C. 6291(36)(C)(ii)(II). 

Other than camcorders, DOE has not identified any end-use consumer products with 

batteries that are not contained inside the product that are not also “fully or primarily motor 

operated.” Therefore, DOE considers only the wall adapters for motor operated products (e.g., 

10 The Sony Handycam HDR-TG1 and the Canon Vixia HF10 are two examples. 

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EERE-2008-BT-STD-0005 COMMENT 03
 

rechargeable power tools and household appliances) to be excluded from the Class A EPS 

definition and the scope of Class A standards. 

Item 5 DOE welcomes comment on any products with detachable batteries that are 

not motor operated, the wall adapters of which should also be excluded from Class A 

EPS standards. 

Finally, it is worth noting that there are no electrical differences between the two battery 

arrangements (i.e., wholly outside versus wholly or partly inside the end-use product). As a 

result, there is no explanation why charging one type of battery would require the associated EPS 

to be excluded from Class A, while charging another type would not. Nonetheless, DOE believes 

that excluding EPSs that charge batteries wholly outside the physical boundaries of the end-use 

consumer product is more appropriate in the context of the language in 42 U.S.C. 6291 

(36)(C)(ii)(II). 

Item 6 DOE requests comment on its interpretation of the definition of “detachable 

battery,” and the impact on EPSs excluded from Class A. 

3.2.3.2 Key Questions 

The above discussion of how to treat wall adapters when used with battery charging 

systems can be reduced to two key questions. The answers to these two questions will determine 

whether DOE will treat a particular wall adapter as an EPS, a part of a BC, both, or neither, and 

will determine which components of a battery charging system are subject to which test 

procedure (BC or EPS) and which standard they must meet. 

Question 1: Should a wall adapter that powers a battery charging system be considered an 

EPS? Based on the answer to this question, DOE will determine whether to test the wall adapter 

to meet the requirements of an EPS energy conservation standard. There are three possible 

answers to this question: 

(1) A wall adapter that powers a battery charging system is always considered an EPS. 

(2) A wall adapter that powers a battery charging system is considered an EPS only if it does 

not perform a charge control function. 

(3) A wall adapter that powers a battery charging system is never considered an EPS. 

Table 3.1. Treatment of Different Types of Wall Adapters That Power a Battery Charging 

System Spending on the Answer to the First Key Question 

Q1: Should the wall adapter be considered an EPS? 

(1) Always (2) Only if no charge control (3) Never 

Wall Adapter Without Charge 

Control Functionality 

Wall Adapter with Charge Control 

Functionality 

EPS EPS Not EPS 

EPS Not EPS Not EPS 

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EERE-2008-BT-STD-0005 COMMENT 03
 

 

Question 2: Should the wall adapter that powers a battery charging system be considered part 

of the BC? There are two possible answers to this question: 

(1) A wall adapter that powers a battery charging system is always considered part of the 

BC. 

(2) A wall adapter that powers a battery charging system is considered part of the BC 

only if it performs charge control functions. 

Based on the answers to these questions, DOE will determine which components of a battery 

charging system will have to meet the requirements of a possible BC energy conservation 

standard. 

Table 3.2. Treatment of Different Types of Wall Adapters That Power a Battery Charging 

System Depending on the Answer to the Second Key Question 

Q2: Should the wall adapt

(1) Always 

er be considered part of the BC? 

(2) Only if charge control 

Wall Adapter Without Charge 

Control Functionality 

Wall Adapter with Charge Control 

Functionality 

BC 

BC 

Not BC 

BC 

3.2.3.3 Possible Approaches to Interpreting the Definitions of BCs and EPSs 

The answers to each of the key questions presented above can be combined in several 

different ways to fully describe the treatment of wall adapters that power battery charging 

systems. These combinations of answers are summarized as one of four possible “Approaches,” 

which are presented in Table 3.3. 

Table 3.3. The Answers to the Key Questions Are Combined to Form Four Distinct 

Approaches to Dealing with Wall Adapters That Power Battery Charging Systems 

Q2: Should the wall adapter be considered part of the BC? 

(1) Always (2) Only if charge control 

(1) Always Approach D Approach not evaluated.* 

Q1: Should the 

wall adapter be 

considered an 

(2) Only if no 

charge control Approach A Approach C 

EPS? 

(3) Never Approach B Approach not evaluated.** 

* DOE will not evaluate this approach further because it would result in too many additional 

product classes as discussed under section 3.2.3.7, Details of Approach D. 

** DOE will not evaluate this approach further because it would require granting an exclusion 

from Class A EPS standards that is inconsistent with EISA (see section 3.2.3.5) and would leave 

some wall adapters entirely outside of the scope of the BC and Class A EPS rulemakings. 

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EERE-2008-BT-STD-0005 COMMENT 03
Figure 3.8 and Figure 3.9 illustrate all the mains-powered product configurations that are 

within the scope of the BC and Class A EPS rulemakings. One of the four approaches, described 

abstractly in Table 3.3, will be applied to each of these configurations during this rulemaking. In 

particular, the key questions presented above concern the middle configurations (Configurations 

2–10) in the two figures, which include a wall adapter that powers a battery charging system. 

Configuration 1 in Figure 3.8 lacks a battery charging system, and is therefore outside the scope 

of this discussion, but was included for the sake of completeness. Similarly, Configurations 11– 

13 in Figure 3.9 lack wall adapters, so, as described in section 3.2.2 there is no question that they 

would be considered BCs in their entirety. 

Because the configurations are similar, with differences only in battery packaging and 

charger interface, it is useful to focus on the distribution of functions within the system. Figure 

3.10 illustrates the four approaches as they apply to generalizations of the product configurations 

presented in Figure 3.8 and Figure 3.9; the details of charger, cradle, and battery have been 

removed while the distributions of functions between the wall adapter and the rest of the system 

have been retained. The following sections detail the advantages and disadvantages of the four 

approaches. 

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EERE-2008-BT-STD-0005 COMMENT 03
AC/DC Conversion Charge control 

Key 

Battery End-Use Load 

Figure 3.8. Configurations of Power Conversion and Battery Charging Functions in 

Consumer Products 

25
 

EERE-2008-BT-STD-0005 COMMENT 03
AC/DC Conversion Charge control 

Key 

Battery End-Use Load 

Figure 3.9. Configurations of Power Conversion and Battery Charging Functions in 

Consumer Products (Continued) 

26
 

EERE-2008-BT-STD-0005 COMMENT 03
 

AC/DC Conversion Charge control 

Key Battery End-Use Load 

EPS BC Overlap 

Figure 3.10. Comparison of How Various Battery Charging Systems Would Be Treated 

Under Each of the Four Approaches. The charge control function can be split between 

enclosures. Enclosures covered by the “overlap” would be considered to be subject to both BC 

and EPS standards. 

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EERE-2008-BT-STD-0005 COMMENT 03
 

 

3.2.3.4 Details of Approach A 

Under Approach A, illustrated in Figure 3.10, DOE would: 

 only consider a wall adapter that powers a battery charging system to be an EPS if it 

does not perform a charge control function; 

 always consider the wall adapter to be part of the BC; and 

 potentially establish two standards: one for the wall adapters that perform only power 

conversion and one for all components of the BC system. 

The July 1, 2008, EISA standard levels were based on efficiency levels used by 

ENERGY STAR and at least 9 States and the District of Columbia. Their EPS efficiency 

programs, however, limited their scopes to wall adapters providing only power conversion 

functions,11 so the standards these programs—and subsequently Congress—adopted were 

developed specifically for these types of wall adapters. By adopting Approach A, which would 

harmonize with these prior programs, DOE would be ensuring that the current Class A EPS 

standards apply to all the wall adapters for which they were originally developed. 

For the purposes of describing BCs, this approach considers the entire battery charging 

system—from wall plug to battery—to be a BC. Any wall adapter that powers a battery charging 

system is a component of “a device that charges batteries for consumer products”—i.e., a BC— 

even if it is also considered an EPS and subject to EPS standards. (42 U.S.C. 6291(32)) Under 

this approach some battery charging systems would be subject to two standards: a BC standard 

for the battery charging system as a whole—from wall plug to battery—and an EPS standard 

specifically for the wall adapter. EISA permits this possibility since it provides that “an energy 

conservation standard for external power supplies shall not constitute an energy conservation 

standard for the separate end-use product to which the external power supply is connected.” (42 

U.S.C. 6295(u)(4)) 

Because Approach A would treat only wall adapters without charge control as EPSs, all 

devices subject to the EPS standards analysis would provide similar utility as constant-voltage 

sources. As a result, all EPSs could be held to a consistent set of standards, requiring no 

additional product classes (see section 3.6.2). Likewise, DOE expects the product-class divisions 

within the BC analysis to be straightforward because under this interpretation of the BC 

definition, all components of a battery charging system would be included in the standards 

analysis—extending from the wall plug to the battery. Thus, all AC mains-powered BCs would 

contain the same circuit functions—whether they are located within the consumer product, 

charging cradle, or wall adapter—and could be included within the same overarching product 

class before being separated by output voltage as described in section 3.6.1. An additional 

product class would be required to analyze DC-powered BCs. 

11 The ENERGY STAR and State programs specifically exclude wall adapters that “have batteries or battery packs 

that physically attach directly” or “have a battery chemistry or type selector switch AND an indicator light or state 

of charge meter.” (EPA. “ENERGY STAR Program Requirements for Single-Voltage External Ac-Dc and Ac-Ac 

Power Supplies: Eligibility Criteria.” Version 1.1 (emphasis in original).) These exclusions would apply to wall 

adapters with battery charging functions. 

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EERE-2008-BT-STD-0005 COMMENT 03
 

 

However, this approach would also introduce some overlap between the BC and EPS 

definitions, which would affect DOE’s analysis. Because certain wall adapters would be 

considered both EPSs and components of BC systems, the potential for energy savings may have 

to be analyzed sequentially. First, an economically justified and technologically feasible standard 

level would have to be developed for the wall adapter during the EPS analysis. Then, given a 

wall adapter that meets a particular EPS standard level, an economically justified and 

technologically feasible standard level would have to be developed for the system as a whole. 

As a result, a separate product class may have to be created to accurately analyze BCs 

powered by wall adapters that are also considered EPSs. However, based on testing and 

discussions with manufacturers, DOE believes that the majority of wall adapters used for battery 

charging applications have charge control functions, leaving only a small percentage of these 

wall adapters that would be considered EPSs under Approach A.12 

An added complication of the overlap between BC and EPS standards is the possibility 

that future EPS standards may impose a design constraint resulting in lower cost-justified energy 

savings than a single system-wide BC standard. This is because complying with future EPS 

standards may prevent implementing cost-justified energy efficiency improvements in the 

remainder of the BC system. (DOE would need to evaluate the likelihood of this possibility.) 

Furthermore, a general EPS analysis of a wall adapter independent of the battery charging 

system it powers would not fully account for the loading and usage of the battery charger as 

accurately as a dedicated battery charging system analysis. 

This problem could, however, be mitigated through the addition of product classes 

specifically for BCs powered by EPSs. By placing these products in a separate product class, 

DOE could exempt the wall adapters from additional EPS standards beyond those required by 

EISA, resulting in only one new system-wide BC standard. DOE may decide to exempt products 

in this class from additional EPS requirements beyond EISA, based on consideration of the seven 

EPCA factors (see section 1.2.2), particularly given the potential for additional cost-justified EPS 

energy savings and an analysis of burdens on the manufacturer. A single system-wide standard 

for BCs powered by EPSs could result in higher cost-justified energy savings. 

Finally, Approach A would require manufacturers to qualify and certify some wall 

adapters as compliant with EPS standards and subsequently re-qualify the entire battery charging 

system powered by the wall adapter as compliant with BC standards. However, as mentioned 

above, DOE does not believe that a significant number of battery charging systems use wall 

adapters that would be considered EPSs under Approach A. Futhermore, DOE does not expect 

the absolute duration of the qualification process to increase, as manufacturers should be able to 

qualify the wall adapter and the entire battery charging system in parallel, if the wall adapter is 

not already qualified under EISA. 

12 Furthermore, many battery charging systems powered by wall adapters either have detachable batteries or are 

“fully or primarily motor operated” and, therefore, are not subject to the EISA EPS standards. DOE is currently 

analyzing whether an energy conservation standards rulemaking should be conducted for these products. 

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EERE-2008-BT-STD-0005 COMMENT 03
 

Nonetheless, even if qualification and certification are conducted in parallel, adopting 

this approach could double the testing and documentation burden on manufacturers compared to 

a single system-wide BC standard (e.g., as under Approach B). Similarly, in cases where 

manufacturers outsource the design and production of the BC wall adapter, these compliance 

costs would affect the final cost of the product. This burden could be reduced if DOE places BCs 

powered by EPSs into a separate product class, as described above. 

Nonetheless, because of its consistency with the ENERGY STAR and State approaches, 

its inclusion of a large number of wall adapters under the current EISA EPS standards, and the 

possibility of reducing manufacturer compliance burdens, DOE believes that the benefits of 

Approach A outweigh the disadvantages. Accordingly, DOE proposes Approach A as its 

preferred approach. 

To summarize, under this approach, DOE would only consider wall adapters that do not 

perform a charge control function to be EPSs, while it would consider all wall adapters to be part 

of the BC, even if they are also considered EPSs. The advantages of this approach are that: 

 it is consistent with the ENERGY STAR and State interpretations of EPS definition 

and testing of products; 

 it provides the second greatest scope of coverage and savings for current EPS 

standards (equal to Approach C, second to Approach D); and 

	 it provides for an overall battery charging system standard (in addition to the EPS 

standard for some wall adapters) such that the system is tested in a manner similar to 

how it is operated. 

The disadvantages of this approach are that: 

	 it subjects BC manufacturers using wall adapters without charge control to both EPS 

and system-wide BC standards, potentially increasing compliance burden; and 

	 it may result in lower cost-justified energy savings than a single system-wide BC 

standard (unless certain wall adapters are exempted from EPS standards beyond 

EISA); 

3.2.3.5 Details of Approach B 

Under Approach B, illustrated in Figure 3.10, DOE would: 

 never consider a wall adapter that powers a battery charging system to be an EPS; 

 always consider the wall adapter to be part of the BC; and 

 potentially establish separate BC standards for the battery charging system and EPS 

standards for wall adapters that do not power battery charging systems. 

This approach is based in part on the EPA ENERGY STAR “heat, light, and motion” 

approach13 used to differentiate between EPSs and BCs that DOE initially considered adopting 

wholecloth. Under this ENERGY STAR approach, a product is classified as either a BC or EPS, 

13 EPA. “ENERGY STAR Program Requirements for Products with Battery Charging Systems: Eligibility Criteria.” 

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EERE-2008-BT-STD-0005 COMMENT 03
 

but not both.14 Qualifying devices under the BC category are further limited to (1) chargers 

packaged with “products whose principal output is mechanical motion, light, the movement of 

air, or the production of heat,” and (2) stand-alone chargers for removable and standard-size 

alkaline-battery replacement batteries. The ENERGY STAR approach is illustrated in Figure 

3.11. 

Source: U.S. EPA, 2009. 

Figure 3.11. EPA ENERGY STAR Division Between Products Qualifying Under the EPS 

and BC Specifications. This division is similar to that under consideration in Approach B. 

The ENERGY STAR approach eliminates overlap between the BC and EPS categories 

and would potentially reduce the compliance burden on manufacturers while resulting in higher 

economically justified energy savings. The ENERGY STAR BC and EPS divisions, however, 

conflict with the statutory BC definition, which is not limited to chargers used for heat, light, and 

motion products or stand-alone chargers. Consequently, when considering the scope set out in 

the statutory definition of a BC, DOE has determined that the ENERGY STAR Program 

approach is too narrow and would not permit DOE to satisfy its legal obligations under the 

statutory framework laid out by Congress. 

To address these shortcomings, DOE developed Approach B, which is similar in structure 

to the ENERGY STAR approach, but attempts to address the coverage issues presented by the 

statutory BC definition. Like the ENERGY STAR approach, Approach B results in no overlap 

between BC and EPS standards. But in contrast to ENERGY STAR, all components of the 

battery charging systems for every application are considered BCs, not just chargers for heat, 

light, and motion applications. 

14 EPA defines EPSs in terms similar to those used in section 301 of EISA to define Class A EPSs. (42 U.S.C. 

6291(36)(C)(i)) 

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EERE-2008-BT-STD-0005 COMMENT 03
 

 

 

Under this broader reading of the BC definition, the scope of the BC standard would 

include battery chargers embedded in products such as cellular telephones and laptop computers. 

The wall adapters of these products have been considered to be EPSs by the ENERGY STAR 

program and the ten States that have adopted EPS definitions and standards based on ENERGY 

STAR.15 

However, to prevent an overlap between BC and EPS standards, these wall adapters 

would not be considered EPSs under Approach B. Instead, DOE would interpret the phrase 

“consumer product” in the EPS definition to exclude devices already regulated separately under 

the BC standard. Although this interpretation would clarify the ambiguities in the BC and EPS 

definitions and resolve the issues with overlapping regulation raised by Approach A, it would 

result in a smaller scope of coverage for the current Class A EPS standards than Approaches A, 

B, and C, and may not be consistent with some additional requirements contained in EISA. 

Specifically, DOE cannot limit the scope of the EPS definition by adding another 

exclusion to those already created by Congress. Section 301 of EISA amended section 321 of 

EPCA by inserting a definition for Class A EPSs. In addition to defining a Class A EPS, EISA 

also created two specific exclusions for products that would otherwise be considered Class A 

EPSs. EISA excludes “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)) This exclusion limits its scope to those devices that (1) power the charger of a 

detachable battery pack or (2) charge the battery of a product that is fully or primarily motor 

operated. Congress did not authorize DOE to add to these exclusions. 

Given these specific statutory exclusions, and the absence of any statutory authority to 

add to these exclusions, DOE cannot create additional exclusions for Class A EPSs beyond those 

that Congress already created. Nonetheless, DOE has included this approach in the discussion 

because of its similarity to the accepted ENERGY STAR approach and potential for lower 

compliance burdens on manufacturers. 

Item 7 DOE welcomes comment on ways of amending Approach B to make it 

consistent with the statutory language in EISA, or proposals of alternate approaches 

based on the clear BC and EPS divisions of the ENERGY STAR program. 

In this context, it is worth emphasizing the possibility of creating a separate product class 

for wall adapters that power battery charging systems but that provide no charge control 

functions (and would therefore be considered EPSs under Approach A). See section 3.2.3.4, 

above. By placing these types of wall adapters into a product class separate from wall adapters 

15 To date, none of the states have adopted standards for BCs, and only one—California— has adopted a test 

procedure. Furthermore, none of the states have issued guidelines on delineating BCs and EPSs. 

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EERE-2008-BT-STD-0005 COMMENT 03
for other applications, these wall adapters could be subject only to future BC standards as 

components of a BC system. 

Treating wall adapters in this manner, Approach A becomes similar to Approach B and 

the ENERGY STAR approach, by removing overlap between future BC and EPS standards since 

only wall adapters for non-battery charging applications would be potentially subject to amended 

EPS standards. Similarly, wall adapters that are part of a battery charging system—together with 

any other enclosures that include the charge-control circuitry—would only be subject to a 

system-wide BC standard. Therefore, there would be no overlap between the scope of the two 

standards. 

The benefits of this elaboration to Approach A, as opposed to Approach B, are that it is 

consistent with the statute and would result in a larger number of wall adapters currently subject 

to the Class A EISA EPS standards, and greater immediate energy savings. 

Despite the advantages of Approach B, DOE will be unable to adopt this and similar 

approaches due to their exclusion of wall adapters that power battery charging systems from 

current EPS standards. Were it possible to implement it, the advantages of Approach B would be 

that: 

	 it eliminates overlap between the scopes of EPS and BC standards, limiting 

manufacturer burden of complying with one standard for both manufacturers of 

individual components and the entire BC-EPS system; and 

	 it provides broadest scope for system-wide BC standard (all components of battery 

charging systems), resulting in maximum economically justified energy savings. 

The disadvantages of Approach B would be that: 

 it is inconsistent with the EISA definition of Class A EPSs; 

 it excludes wall adapters for applications such as laptops and cell phones from EPS 

standards, contrary to ENERGY STAR and State precedent; and 

	 it provides the smallest scope of coverage and savings for current EPS standards, by 

interpreting the EPS definition to exclude any wall adapter that powers a battery 

charger, including applications such as laptops and cell phones. 

3.2.3.6 Details of Approach C 

Under Approach C, illustrated in Figure 3.10, DOE would: 

 consider a wall adapter that powers a battery charging system to be an EPS only if it 

does not perform charge control functions; 

 consider the wall adapter to be part of the BC only if it performs charge control 

functions; and 

 establish separate EPS standards for some wall adapters and BC standards for the 

remainder of the components of the battery charging system. 

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EERE-2008-BT-STD-0005 COMMENT 03
Approach C is similar to Approach A in its interpretation of the EPS definition; however, 

its interpretation of the BC definition is different. Under Approach C, DOE would interpret the 

EPS definition to include all wall adapters that perform no charge control functions. However, 

the Department would interpret the definition of a BC to apply only to battery charging system 

components intended exclusively for battery charging. This interpretation would therefore 

consider a wall adapter that powers a battery charging system to be part of the BC only if it 

performs charge control functions. 

Like Approach A, Approach C would apply EPS standards only to wall adapters that 

perform no charge control functions, which would harmonize this approach with the ENERGY 

STAR and State approaches. Approach C would, however, eliminate overlap between BC and 

EPS standards because a wall adapter that does not perform charge control function would not be 

considered as part of the BC. As a result, components of the same battery charging system could 

be subject to two separate, but disjointed, standards: an EPS standard for wall adapters with no 

charge control functions, and a BC standard for the remaining components of the BC system. 

Like Approach A, Approach C would subject all wall adapters currently within the scope of the 

ENERGY STAR program to the current Class A EISA standards, providing the second greatest 

scope of coverage for current standards. 

Even though there is no overlap between the EPS and BC standards under Approach C, 

applying separate standards to components of a system may still result in higher manufacturer 

burden and lower economically justified energy savings than a single, system-wide standard. 

Manufacturers of a single product would have to comply with two efficiency standards on 

different components of the product, while an analysis conducted under approach C would 

ignore any technology options that rely on the interaction between two components considered 

BCs and EPSs, respectively, to produce energy savings. Furthermore, by including the wall 

adapter within the scope of the general EPS standards analysis, it is not possible to account fully 

for the particular load presented by the battery charging system, since the application of the 

generic EPS loading conditions and usage profiles may not be completely representative of BC 

loads. 

Finally, unlike Approach A, there is no way to mitigate these concerns since Approach 

C’s definition of BC does not include the wall adapter, DOE cannot exclude wall adapters for 

BCs from possible future EPS standards, while subjecting them only to system-wide BC 

standards. 

Approach C also requires additional product classes. Unlike Approaches A and B, where 

the interpretation of EPS and BC definitions placed similar types of products within the scope of 

EPS and BC standards, under Approach C, the BC standard would include two distinct types of 

battery chargers. The first class of BCs, using an internal power supply or wall adapter with 

charge control circuitry for power conversion, would be tested with the power supply, and its 

presence would be reflected in the efficiency test results. In contrast, the second class, utilizing a 

voltage-source wall adapter subject to EPS standards, would be tested without the wall adapter to 

prevent overlap between the standards, which means that the power supply would not be 

included in the test results. Accordingly, the energy consumption of the two classes would not be 

directly comparable, requiring the use of separate standards. 

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To conclude, Approach C is similar to Approach A in that the definition of EPS is 

interpreted to include only wall adapters without charge control. It differs in its interpretation of 

the BC definition, which includes the wall adapter if it contains charge control functionality. The 

advantages of this approach are that: 

 it is consistent with the ENERGY STAR and State interpretation of the EPS 

definition and testing of products; and 

 it provides the second greatest scope of coverage and savings for current EPS 

standards (equal to Approach A, second to Approach D). 

The disadvantages of this approach are that: 

	 like Approach A, it subjects components of battery charging system powered by a 

wall adapter without charge control to EPS and BC standards, potentially increasing 

compliance burden for manufacturers of the entire BC-EPS system; and 

	 like Approach A, it will result in future equal or lesser cost-justified energy savings 

than a single-system-wide BC standard for BCs powered by EPSs. 

3.2.3.7 Details of Approach D 

Under Approach D, illustrated in Figure 3.10, DOE would: 

 always consider a wall adapter that powers a battery charging system to be an EPS; 

 always consider the wall adapter to be part of the BC; and 

 potentially establish two standards: one for wall adapters and one for the BC system 

as a whole. 

Unlike the previous approaches, which considered the circuit function when determining 

whether a component of a battery charging system should be subject to the EPS or potential BC 

standard, Approach D takes into account only the physical characteristics of the device. An EPS 

“converts household electric current into DC current or lower-voltage AC current,” and in the 

discussion of Approaches A and C, DOE indicated that this clause can be interpreted to exclude 

wall adapters that perform charge control functions and are intended solely to charge batteries 

(sections 3.2.3.4 and 3.2.3.6). However, one could also view wall adapters as providing charge 

control functions in addition to converting household current into lower voltage DC current and 

should therefore be considered EPSs. 

Further, while the EISA definition of a Class A power supply is modeled on the 

ENERGY STAR EPS definition, it contains a significant difference. Whereas the ENERGY 

STAR EPS definition excludes devices that “have batteries or battery packs that physically 

attach directly . . . to the power supply unit,”16 the EISA Class A definition does not. Because 

the EISA definition omits this exclusion, wall adapters that “physically attach directly” to the 

16 EPA. “ENERGY STAR Program Requirements for Single-Voltage External Ac-Dc and Ac-Ac Power Supplies: 

Eligibility Criteria.” Version 1.1 (emphasis added). 

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battery may now be considered as Class A EPSs. These wall adapters, however, are equipped 

with charge control, which is necessary when the wall adapter is connected directly to the battery 

to limit the charge current and prevent overheating. Therefore, the removal of the above 

exclusion from the EISA Class A EPS definition seems to imply that EPSs with charge control 

functionality could be included under the definition of Class A EPSs and therefore EPSs in 

general. This would expand the scope of coverage of current Class A EISA standards to all wall 

adapters, not just those that have been considered EPSs under ENERGY STAR. 

Under Approach D, all components of a battery charging system would be considered 

within the scope of the BC definition, similar to Approach A. This interpretation would likewise 

cause overlap between BC and EPS standards, with wall adapters that power battery charging 

systems considered both EPSs and components of BCs. Similarly as under Approaches A and C, 

this overlap may result in a higher compliance burden and lower cost-justified energy savings 

than achievable under single, system-wide BC standards. 

Also, because wall adapters with and without charge control would be considered EPSs, 

these two types of devices would need to be grouped into separate overarching product classes 

and be subject to two different standard levels. This would be necessary because wall adapters 

with charge control provide additional utility and may not be able to meet the same standard 

levels as wall adapters without charge control. 

Thus, although Approach D would facilitate the differentiation between BCs and EPSs by 

allowing quick visual inspection, differentiating wall adapters based on charge control function 

cannot be eliminated entirely and would complicate the downstream analysis and potential EPS 

standards.17 

By modifying Approach D to exclude wall adapters without charge control function from 

the scope of the BC definition, DOE could decrease the number of wall adapters potentially 

subject to both BC and EPS standards. Under this alternate approach, all wall adapters would be 

considered EPSs, but wall adapters without charge control would not be subject to BC standards. 

DOE did not consider this alternate approach because it would further add to the product classes 

required under Approach D, as separate standards for wall adapters with and without charge 

control would be needed as well as separate standards for BCs powered by wall adapters with 

and without charge control. 

However, the complications may go beyond separate product classes and standard 

levels—some wall adapters with charge control may not be testable under the EPS test 

procedure. As presented in Figure 3.7, some wall adapters for battery charging applications 

provide a constant current, rather than a constant voltage. This constant current varies from unit 

to unit due to manufacturing tolerances, such that a particular unit may not be able to deliver its 

nameplate current. Under these conditions, a manufacturer may not be able to test a wall adapter 

with charge control under the EPS test procedure, which requires loading the unit to 100 percent 

of its nameplate current, further complicating the implementation of Approach D and any similar 

approaches. 

17 Differentiating wall adapters based on charge control function would require testing of output current and voltage 

under load, as described in section 3.2.4. 

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EERE-2008-BT-STD-0005 COMMENT 03
Item 8 DOE seeks comment on the prevalence of wall adapters for battery charging 

applications that may not be testable under the EPS test procedure. 

To summarize, under Approach D, all wall adapters would be considered EPSs, while all 

components of a battery charging system, including those wall adapters that are considered 

EPSs, would be considered BCs. There would be significant overlap between the two definitions 

and scopes of potential standards. The advantages of this approach are that: 

	 it simplifies identification of EPSs by relying solely on physical characteristics; and 

	 it provides the greatest scope of coverage and savings for current EPS standards, 

because it considers all wall adapters (even those with charge control) to be EPSs and 

therefore subject to the current EISA standards. 

The disadvantages of this approach are that: 

	 it subjects wall adapters without charge control that power battery charging systems 

to both EPS and system-wide BC standards, potentially increasing the compliance 

burden for manufacturers of individual components as well as the entire BC-EPS 

system; 

	 it may result in lower cost-justified energy savings than a single, system-wide BC 

standard (unless certain wall adapters are exempted from EPS standards beyond 

EISA); 

	 it may lead to complications associated with testing wall adapters that perform charge 

control according to the EPS test procedure; 

 it would result in additional product classes and potential standard levels; and 

 it is inconsistent with ENERGY STAR and State interpretation of EPS definition and 

product testing. 

3.2.3.8 Summary of the Four Approaches 

DOE evaluated the above four approaches based on the desirable criteria presented in 

Table 3.4, assigning a “+” (advantage), “0” (neutral), or “–” (disadvantage), depending on how 

well the approach met each criterion. 

Table 3.4. Comparison of the Four Approaches to Interpreting the BC and EPS Definitions 

Against Desirable Characteristics 

Criterion 

Approach 

A 

Approach 

B 

Approach 

C 

Approach 

D 

Is consistent with the EISA Class A EPS definition + – + + 

Provides a broader scope of coverage for current EPS 

standards 0 – 0 + 

Results in higher cost-justified energy savings 0 + – 0 

Subjects manufacturers to lower compliance burdens – + – – 

Results in fewer potential product classes + + 0 – 

Is consistent with ENERGY and State EPS efficiency + 0 + 0 

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EERE-2008-BT-STD-0005 COMMENT 03
Criterion 

Approach 

A 

Approach 

B 

Approach 

C 

Approach 

D 

programs 

Provides a BC definition that encompasses entire battery 

charging system + + 0 + 

Item 9 DOE seeks comments on the four approaches to interpreting the BC and EPS 

definitions to resolve ambiguities in the scope of the analyses. DOE is also interested in 

determining whether Approach B could be modified to permit its use in a manner 

consistent with the statutory framework created by Congress. 

Item 10 DOE welcomes comment on additional functionality provided by some wall 

adapters for battery chargers that may impede their ability to meet the same standards as 

comparable wall adapters for other applications. DOE asks that commenters provide 

specific examples and suggest ways in which DOE can address any potential barriers 

that may arise. 

Item 11 DOE welcomes comment on the manufacturer burden of compliance with 

current EISA Class A EPS standards under each of the four approaches and seeks 

information on how DOE can minimize this burden while ensuring that the standards are 

being met consistently by the industry. 

Item 12 DOE also welcomes comment on the likely manufacturer burden of 

compliance with possible future EPS and BC standards under each of the four 

approaches. To this end, DOE also seeks information from the industry regarding how 

the monitoring of compliance with these standards can be accomplished. 

3.2.4 Identification of Wall Adapters 

The above approaches depend on identifying whether wall adapters that power battery 

charging systems also perform charge control functions, a task that is not always straightforward. 

To aid in this process, DOE is considering the adoption of three possible criteria to help identify 

those wall adapters that perform charge control functions: 

(1) Short-circuit operation: How the wall adapter performs when a short-circuit load is 

applied. 

(2) Voltage regulation: How the output voltage of the wall adapter varies at different 

active mode loading conditions relative to the nameplate output voltage. 

(3) No-load voltage: How the output voltage of the wall adapter varies at no load relative 

to the nameplate output voltage. 

Short-circuit operation is important to battery charging because a fully discharged battery 

connected to a battery charging system approximates a short circuit. The battery charger must be 

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EERE-2008-BT-STD-0005 COMMENT 03
 

 

designed to operate in this condition. It cannot cut off current to the battery completely, but must 

provide sufficient current for the battery to charge safely. For wall adapters without charge 

control that do not connect directly to batteries, a short circuit is an abnormal fault condition. In 

that case, the wall adapter may cut off all current to the output through a fuse or other protective 

element. 

In addition to short-circuit operation, DOE is considering voltage regulation and no-load 

voltage as possible criteria for determining the presence of charge control functions and the 

placement of a particular wall adapter within the scopes of the BC and EPS definitions under the 

four approaches. A wall adapter for non-battery charging applications is a voltage source that 

ideally provides constant output voltage with variable output current. In contrast, battery 

charging requires a current source that provides constant current with variable output voltage. 

However, some line-frequency wall adapters that are not used in battery charging 

applications tend to have poor voltage regulation,18 which limits the usefulness of this criterion 

because their voltage regulation and no-load voltage might be similar to that of a wall adapter 

that performs charge control. 

Item 13 DOE is seeking input on these and any additional criteria it should consider 

in determining the presence of wall adapter charge control functions. 

DOE is also considering requiring identification labels to easily differentiate between 

wall adapters that perform charge control functions and those that do not, as identified using 

criteria such as those listed above. Manufacturers could be required to label a wall adapter based 

on whether it performs charge control functions. Under Approaches A and C, this label would 

determine whether the wall adapter should be subject to an EPS standard or should be considered 

as part of the entire battery charging system, and therefore subject to a BC standard. Under 

Approach D, this label would determine which EPS product class a wall adapter belongs to, and 

therefore, which standard it may be required to meet. In any case, the label would serve only to 

expedite standards enforcement; because labeling is vulnerable to manipulation, DOE would also 

need to check whether the correct label has been applied through the more extensive tests noted 

above. 

Item 14 DOE welcomes comment on external characteristics (either physical or 

electrical) that can be used to identify a wall adapter performing charge control for 

determining compliance with the appropriate standard under Approaches A, C, and D, as 

well as the use of labeling to permit easy identification. How likely would it be that those 

requirements would be subject to potential manipulation by manufacturers? If 

manipulation is possible, what form, and in what context, would these activities likely 

occur? 

18 “Regulation” refers to the dependence of output voltage on output current. Ideal voltage sources have excellent 

voltage regulation, meaning the voltage does not vary significantly with output current. 

39 

EERE-2008-BT-STD-0005 COMMENT 03
 

3.3 Market Assessment 

DOE will qualitatively and quantitatively characterize the structure of the markets for 

BCs and EPSs. In the market assessment, DOE will identify and characterize the manufacturers 

of this equipment, estimate market shares and trends, address regulatory and non-regulatory 

initiatives intended to improve the efficiency or reduce the energy consumption of BCs and 

EPSs, and explore the potential for technological improvements in the design and manufacturing 

of these products. 

This market assessment will establish the context for the rulemaking, and it will serve as 

a resource to guide the analyses that follow. For example, DOE may use historical shipments and 

prices as an indicator of future shipments and prices. Similarly, DOE may use market structure 

data for the manufacturer impact analysis, as those data could be particularly useful for assessing 

competitive impacts. 

DOE recognizes that there may be limited public information on national shipments, 

manufacturing costs, distribution channels, and manufacturers’ market shares of BCs and EPSs. 

These types of data are important inputs to analyses that determine if energy conservation 

standards are economically justified and will result in significant energy savings. Therefore, 

DOE encourages interested parties to submit data pertaining to these areas of interest that would 

improve DOE’s understanding of the BC and EPS markets. These data may be provided under a 

confidentiality agreement with DOE’s contractors responsible for this part of the rulemaking 

analysis, namely Navigant Consulting, Inc. (NCI) and/or D&R International, Ltd. As with other 

DOE rulemakings, DOE’s contractors will aggregate data provided by manufacturers and other 

organizations when preparing results for DOE’s analyses. These aggregated results do not 

divulge the sensitive raw data from each interested party, but enable other parties to review and 

comment on the aggregated dataset. 

Alternatively, interested parties may submit confidential data to DOE, indicating in 

writing which data should remain confidential. To prevent public disclosure of the data as a 

result of third-party actions, interested parties providing confidential information to DOE must 

submit that data according to 10 CFR 1004.11. Under 10 CFR 1004.11, any person submitting 

information that he or she believes to be confidential and exempt by law from public disclosure 

should submit two copies. One copy of the document shall include all the information believed to 

be confidential, and the other copy of the document shall have the information believed to be 

confidential deleted. DOE will determine whether the information is confidential and treat it 

accordingly.19 

19 Factors of particular interest to DOE when evaluating requests to treat submitted information as confidential 

include the following: (1) a description of the items; (2) whether and why such items are customarily treated as 

confidential within the industry; (3) whether the information is generally known by or available from other sources; 

(4) whether the information has previously been made available to others without obligation concerning its 

confidentiality; (5) an explanation of the competitive injury to the submitting person which would result from public 

disclosure; (6) a date upon which such information might lose its confidential nature due to the passage of time; and 

(7) why disclosure of the information would be contrary to the public interest. 

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EERE-2008-BT-STD-0005 COMMENT 03
 

The following discussion reviews some aspects of DOE’s market assessment developed 

during its 2006–2007 determination analysis, and presents approaches that DOE may use in the 

forthcoming preliminary analyses. 

3.3.1 Distribution Channels 

Figure 3.12 characterizes the physical distribution networks for BCs and EPSs that DOE 

examined during its initial work for the determination analysis. A component manufacturer sends 

components to a BC manufacturer, who assembles the BC. The BC manufacturer often ships the 

assembled device to a separate original equipment manufacturer (OEM). The OEM incorporates 

the BC into a consumer product and ships the entire package to a retailer, who sells it to the 

consumer. Alternatively, a single company could manufacture both a consumer product and the 

BC that charges it. 

Component Manufacturers 

BC Manufacturers 

Consumer Product Retailers 

Consumers 

OEMs 

Component Manufacturers 

EPS Manufacturers 

Consumer Product 

Retailers 

Consumers 

OEMs EPS 

Distributors 

Battery Charger Distribution External Power Supply Distribution 

Sources: Calwell and Reeder, Manufacturer Incentives for Energy Efficient Power Supplies, 2002; Calwell and 

Reeder, Power Tools: A Hidden Opportunity for Energy Savings, 2002; Collon Lee, Astec Power, Personal 

Communication, 2006; Michael O’Connor and Michael Mueller, Phihong USA, Personal Communication, 2006; 

Power Tool Institute and Association of Home Appliance Manufacturers, DOE Scoping Workshop Transcript, 

January 24, 2007. 

Figure 3.12. BC and EPS Distribution Networks 

Item 15 DOE welcomes comment on the possible differences in distribution channels 

between wall adapters used for battery charging applications that do and do not have 

charge control functions. 

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EERE-2008-BT-STD-0005 COMMENT 03
Like BCs, EPS distribution also begins with component manufacturers. Unlike BCs, 

nearly all EPSs are built by EPS manufacturers. The EPS manufacturer will build either custom 

EPSs for an OEM or stock EPS models designed to work with a variety of consumer products. 

Stock products are manufactured according to popular designs that do not differ based on the 

application and then sold directly to OEMs or to EPS distributors. EPS distributors will then sell 

to retailers or OEMs. OEMs will bundle the EPS with a consumer product, and then sell to 

retailers or directly to consumers. One example of the latter is the direct-to-consumer sale of 

laptop computers. 

3.3.2 Shipments 

In section 2.2.1 of the associated draft technical report, DOE identifies 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). As a result of convergence, some consumers may 

now have fewer devices than in the past, thus reducing the demand for BCs or EPSs. 

	 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. 

Item 16 DOE seeks comments on whether these and/or other factors influence the 

shipments of BCs and EPSs, and the extent to which each trend is likely to affect 

shipments. 

Although some data on the shipments of BCs and EPSs exist, DOE is also examining 

shipment information for applications that use BCs or EPSs. Application-level data are important 

in determining the growth rate of BC and EPS shipments (discussed in section 9) as well as the 

usage characteristics of these products (discussed in section 6). The following are the sources of 

shipment information DOE has identified to date. DOE will update these as newer information 

becomes available. 

 Appliance Magazine. 30th Annual Portrait of the U.S. Appliance Industry. September 

2007. 

 Appliance Magazine. 54th Annual Report: A Ten-Year Review 1997–2006 of the U.S. 

Appliance Industry. May 2007. 

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EERE-2008-BT-STD-0005 COMMENT 03
 

 

 Consumer Electronics Association. US Consumer Sales and Forecasts, 2003–2008. 

July 2007. CEA: Arlington, VA. 

 Darnell Group. External AC-DC Power Supplies: Global Market Forecasts and 

Competitive Environment. Second Edition. 2005. Darnell Group: Corona, CA. 

	 Information Technology Industry Council. ITI PC Committee Projects Shipment 

Growth for 2007-2009. September 2007. Information Technology Industry Council: 

Washington, DC. 

	 TIAX LLC. Assessment of Analyses Performed for the California Energy Efficiency 

Regulations for Consumer Electronics Products. February 2006. TIAX LLC: 

Cambridge, MA. 

	 Unpublished information provided by trade associations. 

Tables 3.1 and 3.2 list the applications for which DOE was able to obtain shipment 

information. DOE intends to use the shipment data it has already collected for BCs and EPSs, as 

well as relevant new data. DOE invites submission of shipment data and specifically seeks data 

on applications not listed below. For a complete list of consumer product applications that use a 

BC or EPS and are considered in this rulemaking, please refer to section 2.3 of the draft technical 

report. 

Table 3.5. BC-Powered Applications for Which DOE Has Shipment Data 

Camcorders Kitchen products 

Digital cameras Personal care products 

Do-it-yourself (DIY) power tools Professional power tools 

Floor care products Universal battery chargers 

Table 3.6. EPS-Powered Applications for Which DOE Has Shipment Data 

Camcorders Notebook computers 

Cordless telephones Portable audio players 

Digital cameras Portable gaming devices 

Flat panel monitors Portable video players 

Flatbed scanners Small liquid crystal display (LCD) TVs 

Ink-jet computer printers Telephone answering devices 

Local area network (LAN) equipment Wi-Fi access points 

Medical devices Wireless telephones 

Modems/fax modems 

Item 17 DOE seeks input on shipment data for BCs and EPSs and the applications 

that use them, including applications that use non-Class A EPSs (section 3.6.2). DOE 

also seeks input on the percentage of applications that are shipped with either a BC or an 

EPS. 

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EERE-2008-BT-STD-0005 COMMENT 03
3.3.3 Regulatory and Voluntary Programs 

DOE has also identified several voluntary and regulatory programs within the United 

States and abroad that address the energy consumption of BCs and EPSs. Because the BC and 

EPS markets are global, these programs may affect the efficiency of BCs and EPSs sold in the 

United States, even in the absence of a similar Federal standard. For an overview of these 

programs, please refer to Appendix F of this document. 

Item 18 DOE invites interested parties to review and comment on domestic and 

foreign efficiency programs relating to BCs and EPSs. 

3.3.4 Market Failures 

To prepare for its review under Executive Order 12866, “Regulatory Planning and 

Review,” DOE will study market failures or other specific problems that may warrant agency 

action. DOE will assess the significance of any problem to determine whether a new regulation 

of BCs and EPSs is warranted. In its initial review of the market, DOE believes that there may be 

asymmetric information (one party to a transaction has better information than the other) 

regarding energy-efficiency opportunities in the BC and EPS markets. Battery chargers and 

external power supplies are generally bundled with the consumer product applications they 

power. Consumer purchasing decisions are based primarily on the merits of the end-use product 

and not the BC or EPS packaged with the product. 

In most cases, the party responsible for deciding which BC or EPS to use with a 

particular application is not the consumer who pays the cost of operating it, but rather the OEM, 

who does not pay the cost of operation. OEMs may decide which BC or EPS to package with 

their product based on the manufacturing cost, not the efficiency of the unit. Because BCs and 

EPSs are often custom-designed for the application, the end user has little ability to choose a 

more efficient power source. 

There may be certain external benefits resulting from the improved efficiency of BCs and 

EPSs that are not captured by users of these devices. These include both environmental and 

energy security-related effects that are not already reflected in energy prices, such as reduced 

emissions of greenhouse gases and reduced use of natural gas and oil for electricity generation. 

DOE seeks comments on the weight DOE should give to these factors when considering the 

maximum efficiency at which the total benefits are likely to exceed the total costs resulting from 

a new standard level. 

Item 19 DOE seeks comments and data from interested parties on these and other 

potential market failures that may apply to BCs and EPSs. 

3.4 Technology Assessment 

The technology assessment focuses on understanding how the product uses energy and 

how efficiency measures can reduce the energy consumption of the BC or EPS. Measures that 

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EERE-2008-BT-STD-0005 COMMENT 03
improve the energy efficiency of the product are called technology options. These are based on 

commercially available technologies as well as prototype designs and concepts. In consultation 

with interested parties, DOE will develop a list of technology options for consideration in this 

rulemaking. Following research into this list of technology options, DOE will consider each 

option against four screening criteria: technological feasibility; practicability to manufacture, 

install, and service; adverse impacts on product utility or availability; and adverse impacts on 

health or safety. (See section 4 for a discussion of these screening criteria.) Technology options 

that pass the four screening criteria are called design options and will be considered as 

appropriate ways of improving the efficiency of the product in the engineering analysis. 

Unlike other products regulated under the DOE Appliances and Commercial Equipment 

Standards Program, BCs and EPSs do not provide an end-user function, but rather serve to 

provide power to consumer products. EPSs convert household AC power to lower-voltage AC or 

DC power required by electronic circuits. BCs perform a similar function, using a battery as an 

intermediary. The BC first stores energy in the battery, which then powers the consumer product, 

allowing it to operate without a power cord. The power systems of certain products may include 

both BCs and EPSs. 

DOE is studying technology options that could improve the efficiency of the BCs and 

EPSs covered in this rulemaking. Accordingly, DOE is reviewing manufacturer catalogs, recent 

trade publications, technical journals, and patent filings. To gather more information, DOE is 

conducting manufacturer interviews and consulting with technical experts who have worked on 

BCs or EPSs. 

BC and EPS designs vary according to the maximum output power of the devices, the 

output voltage, and their intended application. Because the technology options for efficiency 

improvement will still need to meet the design requirements of a particular BC or EPS, a 

discussion of designs and product classes precedes a listing of technology options. 

3.4.1 Battery Charger Design 

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 

45
 

EERE-2008-BT-STD-0005 COMMENT 03
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 these 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 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. 

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 (section 3.4.2), 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. 

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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 an 

option for the baseline 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. 

Item 20 DOE seeks comments on whether the 0.2 C charge-rate division between slow 

and fast chargers is appropriate and seeks detailed information regarding the typical 

charge rates for both categories of BCs. 

3.4.2 External Power Supply Design 

To power a consumer product, EPSs must meet numerous specifications; of these, output 

power and output voltage have the largest impact on EPS efficiency. Together, the output power 

and voltage determine the current, which has the greatest impact on conduction losses and 

associated power dissipation in the EPS.20 EPSs are generally designed to provide power at a 

fixed output voltage with variable current to a consumer product. 

The consumer product powered 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 incorporate output voltage regulation 

to minimize voltage fluctuations caused by load or power source variations. Other applications 

that can tolerate some voltage fluctuation may use simpler EPSs, with no regulation of the output 

voltage. 

In these unregulated line-frequency EPSs, the two main sources of loss are the 

transformer and the rectifying diodes. A transformer consists of 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.21 The quality of the 

metal core, the intensity of magnetic induction, and the gauge of the wires determine transformer 

losses. The transformer secondary current then passes through rectifier diodes that have voltage 

drops that also cause losses. Typically, diodes have a drop of 0.6 volts; this fixed voltage drop 

constitutes a larger share of the losses at lower voltages. 

20 The draft technical report discusses conduction losses in more detail. 21 Magnetic induction is is the coupling of the magnetic fields surrounding the primary and secondary windings, 

allowing the transfer of power from one to the other without a galvanic (i.e., conductive) connection between the 

two.
 

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To achieve voltage regulation, one 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 design or topology. Because the AC/DC conversion stage 

of a regulated line-frequency EPS is essentially the same as that of an unregulated EPS, it has the 

same loss mechanisms. 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 current flowing through it to keep the 

output voltage proportional to a fixed reference. 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 excess voltage across the regulator to achieve the (lower) regulated 

output voltage. The power lost in the regulator is the product of the voltage drop and the load 

current and is dissipated as heat. 

A switching regulator can also follow the line-frequency AC/DC power-conversion stage, 

in place of the linear regulator described above. 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 output at high frequency, adjusting the proportion of “on” time during each 

switching cycle (i.e., the duty ratio) to maintain the regulated output voltage proportional to a 

fixed reference. Due to their higher costs, these switching regulators are not as common as linear 

regulators. 

The unregulated and two-stage regulated EPSs discussed above 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 

current to high-voltage DC, converting it back to AC by switching the current on and off at high 

frequencies. The high-voltage, high-frequency 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 losses, 

weight, and material costs, all of which decrease with transformer volume. 

Although DOE is aware of unregulated switched-mode power supplies used for specific 

applications, most switched-mode EPSs are regulated. In these EPSs, the output voltage signal is 

used to control the primary-side switching element, taking power from mains to match the needs 

of the consumer product load and maintaining a constant output voltage. 

The critical elements in a switched-mode EPS are the transistor, output rectifier, 

transformer, and controller. A transistor acts as a switch that constrains the flow of power into 

the transformer, through the output rectifier and, ultimately, to the consumer product. A 

controller, typically an IC, senses the output voltage of the EPS and switches the transistor on 

and off at frequencies in the kilohertz range. By adjusting the duty ratio, the IC controls both the 

average current through the primary winding of the transformer and the output voltage of the 

EPS. 

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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. The IC can also limit power dissipation in active mode by switching the transistor during 

the lowest portions of its current or voltage wavevorms. As before, the power lost in the 

transistor is proportional to the product of current and voltage, so performing the transistor state 

transition when either quantity is zero significantly decreases losses. 

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, transistor magnetization and resistive losses, controller IC power 

consumption, and rectifier losses. Although the number of different sources of loss is higher in 

switched-mode EPSs than in line-frequency EPSs, the total power lost in switched-mode EPSs 

tends to be lower. (See section 3.7.2 for more discussion on the efficiency of switched-mode 

EPSs.) 

3.5 Measuring Efficiency 

An evaluation of the effectiveness of technology options for efficiency improvement and 

the tradeoffs between them depends heavily on the measures used to quantify the efficiency of 

BCs and EPSs. DOE has already adopted test procedures for measuring the energy consumption 

of both BCs and EPSs. This section presents a brief discussion of the test procedures and any 

issues related to the test procedures that may affect the energy conservation standards 

rulemaking. 

Within this document, the term “energy consumption” is used loosely to refer to power 

dissipation or power consumption of BCs and EPSs in one of their several modes. Likewise, 

“efficiency” can mean EPS active-mode efficiency or BC energy ratio, both discussed in the 

following sections. More generally, “efficiency” can also refer to the energy consumption of a 

BC or EPS against that of comparable devices in any of their modes. 

3.5.1 Measuring Battery Charger Efficiency 

On December 8, 2006, DOE adopted a test method to measure the efficiency of battery 

chargers (section 1.2.1). 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 “nonactive 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 nonactive 

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 active mode 

energy consumption. 71 FR 71340, 71360. DOE is currently developing an approach for 

measuring BC active—i.e. charging—mode energy consumption and is considering adopting a 

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EERE-2008-BT-STD-0005 COMMENT 03
test procedure that would return multiple metrics that would correspond to energy consumption 

in each of the modes of operation of a BC. 

Under this approach, these separate metrics would then be weighted during the energy 

use and end-use load characterization (section 6) to reflect the typical usage of BCs in each 

product class. 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 power consumption in 

one mode for another as long as they meet the mode-weighted power consumption required by 

the standard. 

Also, in a separate rulemaking, DOE amended the BC test procedure, adding 

measurement of power consumption during off mode and standby mode for BCs. As presented in 

the test procedure final rule, standby mode is defined as the condition where the BC is connected 

to mains, the battery or product with an integral battery is disconnected from the charger, and 

any on-off switches are turned on. Off mode is defined to be applicable only to BCs with on-off 

switches, and is the same condition as standby mode, with the caveat that all on-off switches are 

off. Because both off mode and standby mode are nonactive modes, this standby and off mode 

final rule did not expand the test procedure to measure energy consumption in active mode. 74 

FR 13334. 

Item 21 Although DOE intends to revisit this issue in the future, its test procedure does 

not currently measure active-mode energy consumption. Nonetheless, DOE seeks 

comments on how it can best account for energy consumed during active mode. 

Item 22 DOE seeks comments on how DOE could, in a future rulemaking, amend its 

BC test procedure to measure energy consumption in active mode. 

3.5.2 Measuring External Power Supply Efficiency 

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. 

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 

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“matched pairs” that describe the CLSs used in setting potential energy conservation standards, 

discussed further in section 5.1. 

3.6 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 this section, DOE summarizes the various product 

classes used by EISA, ENERGY STAR, and the draft analysis prepared by DOE for the 

determination in 2007. (See section 3.6 of the draft technical report for details on these product 

classes.) 

3.6.1 Battery Charger Product Classes 

There are several capacity- and performance-related features of a BC that could be used 

for classification, including the charging method it uses (continuous charging or terminating 

charging), the charge rate, the voltage or capacity of the battery or batteries charged, and/or the 

battery chemistry. 

For example, ENERGY STAR uses product classes for battery charging systems based 

on the voltage of the batteries or battery packs they charge. The ENERGY STAR specification 

contains 20 product classes, from 1.2 volts to greater than 24 volts, in 1.2 volt increments. 

ENERGY STAR does not distinguish among battery charging systems by charging method, 

charge rate, battery capacity, or battery chemistry. There are no State or international standards 

for BCs. 

In conducting the determination analysis mandated by EPACT and superseded by EISA, 

DOE divided battery chargers into product classes based on battery voltage. This characteristic, 

more than any other, impacts the performance and utility of the battery charger. Battery voltage 

has a large impact on attainable battery charger efficiency as well as the opportunities for 

efficiency improvement. Furthermore, a BC designed for one battery voltage cannot be replaced 

with one designed for another, as it is the consumer product application that sets the battery 

voltage. 

Although one cannot easily exchange a fast charger for a slow one without significantly 

affecting consumer utility, the same cannot be said of the converse. In fact, exchanging a slow 

charger that uses a line-frequency power supply for a fast charger with a switched-mode power 

supply was a technology option for improving efficiency (section 3.7) that manufacturers 

identified during interviews held in 2007. 

Additionally, class divisions based on battery voltage permitted DOE to analyze the 

different technological paths to energy-efficiency improvement in the major categories of BCs 

for consumer products. For example, most chargers for personal-care applications (e.g., shavers, 

beard trimmers, etc.) have an output voltage less than 3 V, while those for power tools have an 

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output greater than 9 V. Using product class divisions based on voltage would, therefore, allow 

DOE to account for the varied usage of chargers for diverse consumer product applications by 

differentially weighting their energy consumption in each mode based on the usage. Table 3.7 

shows the product classes used in the determination analysis, while section 3.6.2 of the draft 

technical report describes them in detail. 

Table 3.7. Battery Charger Product Classes Developed for the Draft Determination 

Analysis 

Battery Voltage Product Class 

0 V through 3 V A 

>3 V through 9 V B 

>9 V through 48 V C 

Item 23 DOE seeks comments on BC product class divisions, including whether 

battery voltage is the appropriate product classification criterion, and/or whether DOE 

should take into account other factors, such as charge rate, battery capacity, or battery 

chemistry. 

3.6.2 External Power Supply Product Classes 

Output power and output voltage have the largest impact on achievable EPS efficiency 

(section 3.5.2); consequently, DOE is considering one or both of these criteria in developing EPS 

product classes for its preliminary analyses. DOE is reviewing EPS product classes created by 

EISA, ENERGY STAR, and manufacturers to determine what role output power and voltage 

play in their definitions. EISA defines Class A EPSs and sets efficiency standards by EPS output 

power. Version 1.1 of the ENERGY STAR specification only considered EPS output power but 

Version 2.0 considers output power, input power, conversion type (AC/DC versus AC/AC), and 

output voltage. 

In a previous analysis presented in section 3.6.1 of the draft technical report, DOE 

developed product classes by output power and output voltage based on manufacturer input. In 

this section, DOE summarizes these methods for establishing product classes and seeks 

comments from interested parties in developing product classes for its preliminary analyses. 

As mentioned in section 1.1, EISA amended EPCA, establishing energy conservation 

standards for Class A External Power Supplies that became effective on July 1, 2008. These 

energy conservation standards divide Class A EPSs into three product classes based on rated 

nameplate output power (in watts): less than 1 watt, 1–51 watts, inclusive; and greater than 51 

watts. Table 3.8 shows the classes and energy conservation standards established by EISA. 

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Table 3.8. EISA Efficiency Standards for Class A EPSs 

Nameplate Output Active-Mode Required Efficiency 

(decimal equivalent of a percentage) 

<1 watt 0.5 times the nameplate output 

1 to 51 watts The sum of 0.09 times the natural logarithm of the nameplate 

output and 0.5 

>51 watts 0.85 

Nameplate Output Maximum No-Load-Mode Power Consumption 

No more than 250 watts 0.5 watts 

Section 321 of EPCA, as amended by section 301 of EISA, defines a Class A External 

Power Supply as 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 through a removable or hardwired male-female electrical connection, 

cable cord, or other wiring; and (6) has nameplate output power that is less than or equal to 250 

watts. 

As such, the product classes listed in Table 3.8 do not apply to EPSs with output power 

greater than 250 watts or with multiple simultaneous output voltages. The statute further 

excludes 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.” All products that are excluded or not 

covered under the definition of “Class A External Power Supply” will be evaluated under the 

determination analysis for non-Class A EPSs required by EPCA, as amended by EISA. See 42 

U.S.C. 6295(u)(1)(E). 

 This topic is discussed further in section 3.2.1. In the context of this section, DOE seeks 

comment on how to extend the product-class divisions for Class A EPSs, introduced by EISA, to 

non-Class A EPSs, or how to create novel product-class divisions for non-Class A EPSs. 

Item 24 DOE seeks comments on creating potential product class divisions for EPSs 

excluded from the EISA definition of Class A. 

The ENERGY STAR program for EPSs, led by EPA, created the first EPS specification 

in 2004 (Version 1.1), and the product classes set forth by ENERGY STAR have affected other 

programs since. On April 23, 2008, EPA issued its ENERGY STAR specification Version 2.0 

for EPSs, where it presented two product class structures (Table 3.9 and Table 3.10) based on 

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output power and output voltage as well as output current, input power, power factor, and 

conversion type (AC/AC or AC/DC). 22 

Table 3.9. ENERGY STAR Version 2.0 Active-Mode EPS Product Classes 

Model Type 

Nameplate Output Power 

≤1 Watt 1–49 Watts >49 Watts 

Low-Voltage Models* A B C 

Standard Models D E F 

*Low-voltage models have output voltage of less than 6 volts and an output current greater than or equal to 550 

milliamps. 

Table 3.10. ENERGY STAR Version 2.0 No-Load-Mode EPS Product Classes 

Conversion Type 

Nameplate Output Power 

<50 Watts ≥50 Watts 

AC/AC Converters W X 

AC/DC Converters Y Z 

These product classes are based on the Version 1.1 product classes, which divide EPSs at 

a no-load-mode consumption of 10 watts and output power of 1 and 49 watts. Version 2.0 

retained these product-class divisions based on feedback from interested parties. Based on 

additional feedback, ENERGY STAR also created separate product classes for AC/AC 

converters, low-voltage units, and high-input-power units.23 

Input from interested parties also prompted ENERGY STAR to create a separate no-load 

power consumption specification for AC/AC EPSs because those converters are typically limited 

to line-frequency architectures and cannot meet the same no-load power consumption levels as 

switched-mode AC/DC EPSs. Additionally, the proposed ENERGY STAR Version 2.0 Program 

Requirements set a less stringent specification for low-voltage units with an “output voltage less 

than 6 volts and an output current greater than or equal to 550 milliamps.”24 Interested parties 

sought a separate product class for low-voltage EPSs because, for the same power, lower output 

voltages result in higher currents and associated conduction losses. Lower voltage EPSs are 

further affected by proportionally greater losses due to voltage drops in the output rectifier. 

Finally, interested parties prompted ENERGY STAR to include minimum power factor 

and efficiency requirements for high-power EPSs with input power of 100 watts or greater, 

where the power factor is the ratio of real power to total power drawn by the EPS. Due to 

22 “ENERGY STAR® Program Requirements for Single Voltage External Ac-Dc and Ac-Ac Power Supplies 

Eligibility Criteria (Version 2.0) Revised Final Draft.” April 2008. Available at 

www.energystar.gov/ia/partners/prod_development/revisions/downloads/Spec.pdf. 23 “Cover Letter to Accompany Final Draft of EPS Specification Version 2.0.” February 19, 2008. Available at 

www.energystar.gov/ia/partners/prod_development/revisions/downloads/CoverLetterV2.pdf. 24 “ENERGY STAR Program Requirements for Single Voltage External Ac-Dc and Ac-Ac Power Supplies 

Eligibility Criteria (Version 2.0) Revised Final Draft.” April 2008. Available at 

www.energystar.gov/ia/partners/prod_development/revisions/downloads/Spec.pdf. 

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nonlinear and energy-storage circuit elements such as diodes and inductors, respectively, 

electrical products often draw currents that are not proportional to the line voltage. These 

currents are either distorted or out of phase in relation to the line voltage, resulting in no real 

power drawn by the EPS or transmitted to the load. However, although the EPS itself consumes 

no real power, these currents are real and cause power dissipation from conduction losses in the 

transmission and distribution wiring. For a given nameplate output power and efficiency, 

products with a lower power factor cause greater power dissipation in the wiring, an effect that 

also becomes more pronounced at higher input powers. Therefore, in light of these concerns, 

ENERGY STAR, through Version 2.0, limits the power factor of EPSs with an input power of 

100 watts or greater, effectively creating an additional product class division based on input 

power. 

Taking into consideration the ENERGY STAR Version 1.1 specification and 

manufacturer suggestions, DOE developed product classes based on output power for its 

determination analysis, presented in section 3.6.1 of the draft technical report. DOE divided the 

EPSs into low-, medium-, and high-power units, with the boundaries at 4 and 60 watts nameplate 

output power. Based on manufacturer inputs, DOE expected EPSs in each product class to share 

design characteristics that would affect the cost of increasing active-mode efficiency and 

decreasing no-load power consumption. For example, DOE did not expect low-power switchedmode EPSs with output power of less than 4 watts to contain a controller IC, due to the high cost 

of an IC in relation to the total cost of the EPS. Because an IC is necessary for reducing power 

consumption at light and no load through such strategies as cycle-skipping, the high proportional 

cost of an IC would lead to an increased cost of improving no-load power consumption for lowpower EPSs. 

Similarly, DOE expected EPSs with output power greater than 60 watts to exhibit a twostage circuit architecture with active power factor correction (PFC), which is necessary for 

meeting power-factor requirements under the European Union Code of Conduct, a voluntary 

agreement of EPS manufacturers described later in Appendix F Due to the global nature of the 

EPS market, these requirements would affect the design of and cost-efficiency relationship for 

high-power EPSs in the United States. 

However, after analyzing 32 EPSs with output power less than 6 watts and 18 EPSs with 

output power greater than 50 watts, DOE was unable to find support for power level product 

class divisions. There were no clear thresholds at which manufacturers would begin to use 

controller ICs or PFC circuitry. Therefore, although DOE recognizes the important role of ICs 

and PFC in EPS design and anticipates further analysis of these criteria, it is not currently 

considering EPS product classes related to these criteria. 

In interviews held in 2007, manufacturers also suggested that DOE differentiate the EPS 

product classes by output voltage in addition to output power. This is because when comparing 

EPSs with the same output power, EPSs with lower output voltages have higher conduction and 

diode-drop losses that pose additional challenges to achieving high efficiency. To address this 

situation, manufacturers suggested that DOE further subdivide its product classes by output 

voltage, with a division at 12 volts, which is the point where the approximately 0.6-volt diode 

drop results in losses equal to 5 percent of the output voltage Table 3.11 presents the product 

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classes that DOE used in its determination analysis and described in detail in section 3.6.1 of the 

draft technical report. 

Table 3.11. Product Classes Used in the EPS Determination Analysis 

Nameplate Output Voltage 

Nameplate Output Power 

<4 Watts 4–60 Watts >60 Watts 

<12 volts A B C 

≥12 volts D E F 

Item 25 DOE seeks comments on whether to consider the presence of ICs or PFC 

circuitry in developing product classes for EPSs. 

Item 26 DOE seeks comments on how to consider output voltage in developing 

product classes, and how the low-voltage division should vary with EPS output power. 

Class A EPSs represent the vast majority of EPSs manufactured and sold. This group 

encompasses a broad range of products with many different designs and end-use utilities and 

applications. DOE is considering a few possible approaches concerning EPS product classes. 

Two options include: (1) subdividing the EISA Class A standard product classes, which are 

based on output power, into even narrower product classes that take into account unit output 

voltage; or (2) establishing new product classes based on output power divisions different from 

what the Class A EISA standard uses. Based on comments from interested parties, DOE may use 

one of these two approaches, modify one approach, or use an entirely different Class A EPS 

product class structure for the preliminary analyses. 

Item 27 DOE seeks comments on the possible approaches discussed concerning EPS 

product classes, and invites interested parties to propose alternative approaches and/or 

other factors DOE should consider in developing product classes for the preliminary 

analyses. 

As discussed earlier, EPCA, as amended by EISA, also requires DOE to conduct a 

determination analysis that considers EPSs other than Class A. While conducting the 

determination analysis, DOE may define additional classes of EPSs, for example, EPSs with 

nameplate output power greater than 250 watts and EPSs that are able to convert to more than 

one AC or DC output voltage simultaneously. If the determination is positive, standards for 

certain additional classes of EPSs may be considered under the scope of this energy conservation 

standards rulemaking. 

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Item 28 DOE seeks comments on how the product classes it is considering for Class A 

EPSs may apply to non-Class A EPSs and whether there are particular issues DOE needs 

to take into account. 

Item 29 DOE seeks comments on all aspects of the product classes it is considering for 

BCs and EPSs, as well as any other methods for establishing product classes in 

accordance with the requirements of 42 U.S.C. 6295(q). 

3.7 Technology Options for Efficiency Improvement 

3.7.1 Battery Charger Technology Options 

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. 

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	 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: 

	 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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4 

3.7.2 External Power Supply Technology Options 

The technology options under consideration that may improve the efficiency of EPSs, as 

discussed in section 3.4.2, are listed below. Because many of the technology options are the 

same as those for BCs, please refer to the discussion in section 3.7.1 for additional details. 

	 Switched-Mode Power Supply: Unlike battery chargers (see above), line-frequency 

EPSs often 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. 

	 Low-Power Integrated Circuits: See Battery Charger Technology discussion above. 

	 Schottky Diodes and Synchronous Rectification: See Battery Charger Technology 

discussion above. 

	 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 ("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. 

Item 30 DOE seeks comments on the preliminary technology options identified in this 

section and whether there are other technology options it should consider. In 

commenting on design options, please discuss their impacts, if any, on safety, 

performance, and consumer utility. 

SCREENING ANALYSIS 

The purpose of the screening analysis is to screen out technology options that DOE will 

not consider in the rulemaking for BCs and EPSs. DOE uses the following process to perform 

this screening. 

DOE starts by developing a list of technology options, developed through its own 

research and in consultation with interested parties, for consideration in the engineering analysis 

(section 5). The identified candidate technology options or best available technologies will 

encompass all those technologies that may be technologically feasible. DOE then reviews each 

technology option or best available technology in light of the following four criteria, as provided 

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in sections 4(a)(4) and 5(b) of the Process Rule.25 These criteria have been tailored to the current 

rulemaking: 

(1)	 Technological feasibility: DOE will not consider technologies that are not 

incorporated in commercially available products or working prototypes. 

(2)	 Practicability to manufacture, install, and service: If DOE determines that mass 

production of a technology in commercial products and reliable installation and 

servicing of that technology could not be achieved on the scale necessary to serve 

the relevant market by the time of the effective date of the standard, it will not 

consider that technology further. 

(3)	 Adverse impacts on product or equipment utility or availability: If DOE 

determines that a technology has a significant adverse impact on the utility of the 

product to significant subgroups of consumers, or results in the unavailability of 

any covered product type with performance characteristics (including reliability), 

features, size, capacities, and volumes that are substantially the same as products 

generally available in the United States at the time, it will not consider that 

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 that 

technology further. 

DOE will document its reasons for eliminating any technology option during the 

screening analysis, and will provide this documentation for review and comment by interested 

parties as part of the preliminary TSD. DOE will call those technology options that are not 

screened out by the above four criteria “design options” and will consider these options in the 

development of cost-efficiency curves in the engineering analysis. 

Item 31 DOE seeks comments on how the four screening criteria might apply to the 

technology options discussed in section 3.7, as well as any additional technology 

option(s) that an interested party recommends to DOE. 

As previously discussed, DOE is considering replacing line-frequency EPSs with 

switched-mode EPSs as a technology option. However, DOE acknowledges that the two 

technologies may not have equivalent utility for certain applications. Although switched-mode 

EPSs attempt to filter the electrical noise from their high-frequency switching, some highfrequency currents may still be present on their input or output lines, where they may interfere 

with nearby electronic equipment, including the load connected to the EPS. DOE has learned that 

certain medical, radio, and media player applications could suffer from electromagnetic 

interference when supplied by a switched-mode EPS instead of a line-frequency EPS. Because 

25 10 CFR Part 430, Subpart C, Appendix A. 

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switched-mode EPSs typically include more protections against short circuit and overcurrent 

conditions, some manufacturers have also reported difficulties when using a switched-mode EPS 

in place of a line-frequency EPS in high-current applications. 

Item 32 DOE seeks comments on any consumer product applications which require 

use of a line-frequency EPS, and which could not accommodate use of a switched-mode 

EPS. 

5 ENGINEERING ANALYSIS 

After conducting the screening analysis described above, DOE will perform an 

engineering analysis based on the remaining design options for efficiency improvement. The 

engineering analysis consists of estimating the energy consumption and cost of products at 

various levels of increased efficiency. Section 5.1 provides an overview of the engineering 

analysis. Section 5.2 discusses the representative units selected for BCs and EPSs. Section 5.3 

describes DOE’s proposed approach to the engineering analysis for both products. Section 5.4 

addresses proprietary designs, and section 5.5 discusses cumulative regulatory burdens that 

might affect the engineering analysis. 

5.1 Engineering Analysis Overview 

The purpose of the engineering analysis is to determine the relationship between BC and 

EPS efficiency and manufacturer selling price.26 This relationship serves as the basis for the 

underlying costs and benefits to individual consumers (section 8, LCC analysis) and the Nation 

(section 10, national impact analysis (NIA)). The output of the engineering analysis provides the 

manufacturer selling price at selected, discrete candidate standard levels (CSLs) of efficiency. 

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.27 

For example, DOE often considers the ENERGY STAR level as one CSL. 

DOE begins the engineering analysis by identifying the representative product classes 

and selecting one representative unit for analysis from each of the representative product classes. 

DOE presumes that findings relating to the representative unit are applicable to all the units in its 

product class. Later, the NIA scales the analytical findings for each representative unit to other 

units in the same representative product class, and from the representative product class to other 

product classes that DOE did not explicitly analyze. 

The analysis of the representative unit begins with the baseline CSL, which models the 

most common, least-efficient devices in a product class. Once DOE selects the representative 

units and establishes baseline CSLs, it may choose one or more possible approaches to arrive at a 

26 This price, which is what manufacturers charge distributors and retailers, forms the basis for the price consumers 

eventually pay. 

27 The “max tech” 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. 

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manufacturer selling price for re-designed devices that match the performance characteristics of 

the representative unit at the baseline CSL, but which have a higher efficiency. DOE has used the 

following four approaches in prior rulemakings: 

(1)	 Examination of published prices and efficiency results: For certain products, 

prices can be obtained from manufacturer or distributor catalogs. For prices 

obtained from catalogs, DOE would apply appropriate discounting to account for 

distributor markup, and catalog prices are typically provided at volumes several 

orders of magnitude lower than those used in typical production. Using these data, 

DOE will estimate the manufacturer selling price. Similarly, the results of 

efficiency tests can often be obtained from manufacturer or distributor literature 

or from the test databases of other regulatory agencies. This approach examines 

only commercially available products and may not provide information about the 

most efficient designs. 

(2)	 Testing and teardowns: DOE can purchase commercially available products and 

conduct its own efficiency tests followed by teardowns (i.e., disassembly of the 

product to obtain a bill of materials (BOM) and valuation of components). In this 

approach, sometimes called “reverse engineering,” DOE estimates the 

manufacturer selling price from the resulting BOM and estimated manufacturer 

markups. DOE examines only commercially available products; therefore, this 

approach may not provide information about the most efficient designs. 

(3)	 Efficiency level approach: DOE interviews product manufacturers, requesting 

estimates of the manufacturer selling price for commercially available as well as 

theoretical units at several CSLs. When providing these data, usually under a nondisclosure agreement, manufacturers characterize their least-cost-path to 

efficiency at each CSL for which DOE requests data. Manufacturers also 

generally provide some information on the design options used. 

(4)	 Design option modeling: In this approach to the engineering analysis, DOE 

develops or subcontracts product design software that simulates the efficiency of 

incorporating various combinations of design options into the representative unit. 

In this approach, the manufacturer selling price at a particular CSL is based on the 

component costs (i.e., BOM) of the design options necessary to achieve it. DOE 

obtains component costs from public and private sources and confirms the 

information during the manufacturer interviews. 

Although DOE may use information about design options to help select a particular CSL, 

the CSLs themselves are not technologically prescriptive and manufacturers are free to use any 

combination of design options to achieve the efficiency of a given CSL. 

Another important consideration in developing CSLs for EPSs is the use of “matched 

pairs” of active-mode efficiency and no-load-mode power consumption. CSLs based on matched 

pairs consist of simultaneous requirements of minimum active-mode efficiency and maximum 

no-load power consumption, instead of a single requirement based on some integrated efficiency 

metric. Matched pairs allow DOE to base CSLs on existing EPS specifications or standards, such 

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as those developed by ENERGY STAR. As these CSL “matched pairs” progress from least to 

most efficient, either one or both metrics (i.e., active-mode efficiency and no-load mode power 

consumption) increase in stringency. By preventing a decrease in the stringency of these metrics, 

DOE makes a tacit assumption that there is no trade-off between EPS performance in the two 

modes, and increasing the energy savings in one mode does not necessarily cause a decrease in 

energy savings in the other. 

Item 33 DOE seeks recommendations on possible candidate standard levels to use 

when analyzing EPSs and BCs. 

5.2 Representative Product Classes and Units 

Once DOE establishes its product classes for BCs and EPSs, it needs to determine which 

to study in the engineering analysis, i.e., whether to analyze all the product classes, or select a 

few representative product classes to study and then scale the findings from those product classes 

to the remainder. Representative product classes are typically chosen to encompass those types 

of devices that have the highest market share or some performance characteristic that deserves 

special consideration. 

Within each of the representative product classes, DOE then selects a representative unit, 

which is the theoretical BC or EPS that DOE will study in the engineering analysis. The 

representative unit is a theoretical unit specified by characteristics such as battery voltage, charge 

rate and battery capacity for BCs, or output power and output voltage(s) for EPSs, among others. 

These characteristics determine the usability of the BC or EPS with a particular end-use product 

application. As long as they are constant between two BCs or EPSs, these power converters are 

assumed to be interchangeable, providing consumers with the same utility. Characteristics such 

as costs and efficiency are variable, allowing DOE to calculate the relationship between 

improvements in efficiency and material costs, while maintaining constant utility. In other 

words, these units serve as reference points against which DOE can measure changes resulting 

from potential energy conservation standards. 

DOE develops a separate engineering analysis for each representative unit. Selection of 

the representative unit is a critical aspect of DOE’s analytical process, because this unit is meant 

to represent the characteristics of common or typical products sold in a given product class. 

Following selection, DOE evaluates the cost of the representative unit at a baseline efficiency 

level and any changes in cost necessary for the unit to meet the higher CSLs. The baseline 

representative unit is often selected to just meet the current energy conservation standard, as is 

the case for Class A EPSs. However, there are no standards in place for BCs. Therefore, DOE 

will select representative units typical of the most common or least efficient products offered for 

sale in the market as the baseline for its analysis. 

Once DOE has completed its engineering and subsequent life-cycle cost analyses on the 

representative units, the results will be scaled from the representative units to the representative 

product classes, and from those product classes to other product classes DOE did not analyze. 

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Item 34 DOE invites comments on the identification and selection of representative 

product classes and on models that may serve as good representative units within each 

product class. DOE also seeks comments on appropriate scaling relationships among 

product classes for both BCs and EPSs. 

5.2.1 Battery Charger Representative Units 

DOE decided to analyze all three BC product classes presented in Table 3.7, as part of its 

determination analysis presented in the draft technical report. Each class was represented by a 

unit that served as the focus of the analysis, except for product class C, which was represented by 

two units, one a slow charger and the other a fast charger. Although most low-voltage batteryoperated applications (product classes A and B) used slow chargers, this was not the case with 

many high-voltage applications, such as professional power tools, which typically ship with fast 

chargers. 

The characteristics of the representative units can be seen in Table 5.1. DOE chose these 

units because they represent high-volume BCs within each of the product classes discussed in 

section 3.4.1. Following the engineering analysis, each of the representative units underwent lifecycle cost and payback period analyses. DOE applied the cost-efficiency curves developed for 

each unit to all the products in its product class during the calculation of national energy savings 

and national net present value. 

Table 5.1. Representative Unit Characteristics for Battery Chargers 

Product Class Battery Voltage Battery Capacity Charge Rate 

Typical 

Application 

A 1.2 V 1.2 Ah 0.1 C Shaver 

B 4.8 V 1.2 Ah 0.1 C Vacuum 

C 18 V 1.5 Ah 0.15 C DIY tool 

C 18 V 2.4 Ah 1 C Pro tool 

5.2.2 External Power Supply Representative Units 

Following further discussion with manufacturers, DOE narrowed its focus within the list 

of the six product classes it had developed for the determination analysis to three representative 

product classes. While the original six product classes, presented in Table 3.11, were based on 

output power and voltage, the three representative product classes, presented in Table 5.2, were 

based solely on output power. DOE chose these representative product classes and criteria for 

division because manufacturers design “families” of EPSs with the same output power, but 

different output voltages. Therefore, for a given output power, low-voltage and high-voltage 

EPSs share the same design, often differing only in the choice of component values. Because of 

this similarity of design, there is a functional relationship between the efficiency achievable by 

units of different output voltage. Therefore, no differential analysis of separate voltage-based 

representative product classes is necessary. 

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For each of the three representative EPS product classes analyzed in 2007 (section 3.6), 

DOE identified a representative unit for evaluation in the engineering analysis. These three units 

were chosen to represent EPSs that ship with high-volume applications, such as laptop computers 

and cellular telephones. For additional discussion, please see section 5.2.3 of the draft technical 

report. 

Table 5.2. Representative Unit Characteristics Used for External Power Supplies 

Product Class Output Power (W) Output Voltage (V) Typical Application 

A 2.75 W 5 V Cellular Telephone 

B 18 W 12 V Modem 

F 90 W 19 V Laptop Computer 

DOE chose the representative unit for Product Class A to represent a typical charger for a 

cellular telephone, the consumer product associated with the highest volume of EPS sales. DOE 

chose Product Class B’s representative unit to be characteristic of mid-power applications such 

as a modem or wireless router. Finally, DOE chose the representative unit for Product Class F to 

represent a high-power application such as a laptop computer or video game console. 

DOE invites interested parties to comment on these three representative units and on 

whether DOE should analyze these or other representative units during the preliminary analyses. 

Note that DOE is publishing some of the results from the tear-down analysis conducted in 2007 

in section 5.5.5 of the draft technical report published in conjunction with this framework 

document. 

Item 35 DOE seeks comments on representative product classes and selection of 

representative units from those representative product classes. 

Item 36 DOE seeks comments on the scaling of findings from representative product 

classes to other product classes that DOE may not explicitly analyze. 

5.3 Engineering Analysis Approach 

This section discusses the Approach DOE intends to follow to estimate the manufacturer 

selling price for each representative unit (section 5.2) at successively more stringent CSLs. 

DOE is considering using three of the four approaches described in section 5.1 to gather 

data on and validate the relationship between manufacturer selling price and efficiency: (1) an 

efficiency level approach, (2) testing and teardowns, and (3) examination of published prices and 

efficiency results. DOE intends to use the manufacturer interviews as one of its data sources, 

structuring the collection of these data around an interview guide similar to the one presented in 

appendices 5.A and 5.B of the draft technical report. DOE will perform its own testing and 

teardowns. DOE will also consult publicly available data to validate the information 

manufacturers provide. 

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Item 37 DOE invites manufacturers to work with DOE in the interviews to help 

develop aggregated curves of manufacturer selling price versus efficiency for the various 

representative units. 

In interviews, manufacturers may provide data for products similar to the representative 

units, rather than the precise representative units. In those cases, DOE will scale the data to be 

consistent with the representative unit. For example, during the interviews conducted in 2007, 

manufacturers provided data on EPSs that were similar to the representative units in terms of 

capacity, functionality, and design, but had slightly different output power or output voltage. 

DOE then used typical relationships between power and efficiency or voltage and efficiency to 

adjust the efficiency data so that it would pertain to the representative unit. 

For example, EPSs with higher output power tend to be more efficient, so the efficiency 

of a lower-power unit would be increased when the data were scaled to a higher-power 

representative unit. This normalization maintained the unit’s relative standing within the market 

in terms of cost and efficiency and accounted for any differences in output power, output 

voltage, volume, and other characteristics and permitted aggregation of cost-efficiency data from 

the maximum number of manufacturers. The normalization method is presented in sections 5.4.5, 

5.4.9, 5.4.10, and 5.4.11 of the draft technical report. 

Item 38 DOE seeks comments on methods for normalizing cost and efficiency data 

provided by manufacturers for EPSs with output power and output voltage that differ 

from those of the representative units. 

Item 39 DOE seeks comments on the shipment volumes to use for the representative 

units. 

To validate the manufacturer-provided engineering data, DOE plans to develop a range of 

possible costs of production, from the bottom up, applying markups to arrive at a manufacturer 

selling price. The process of evaluating the cost of a BC or EPS starts with DOE conducting teardowns of commercially available BCs and EPSs, counting parts, and preparing BOMs. 

Typically, DOE first obtains low-volume BOM costs by summing individual component prices, 

obtained from electronic distributor catalogs using the largest possible retail volume, typically 

500 to 1,000 pieces. 

Because manufacturer selling prices calculated from 1000-piece parts costs are too high 

to meaningfully represent manufacturers’ production costs, in the 2007 determination analysis, 

DOE scaled these low-volume parts costs to reflect what the components would cost in more 

typical (much larger) volumes. In developing this more typical volume, DOE used a highvolume quote obtained from a distributor to perform the scaling, a process that consisted of 

calculating scaling ratios of low- and high-volume parts costs for several types of parts, and 

applying them to all parts of that type in each low-volume BOM. The high-volume parts costs 

were quoted at a volume of 500,000 pieces, which DOE considers to be a typical yearly volume 

of a single EPS design for a mid-size manufacturer. 

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After deciding on an appropriate volume, DOE then applied manufacturer markups to the 

resultant high-volume BOM cost to account for additional manufacturer costs not included in the 

BOM. These markups included (1) a production markup, (2) an add-on for packaging and 

mechanical components, and (3) a non-production markup. The production markup included all 

direct and indirect labor, indirect materials, local taxes, and factory operating expenses. In 

addition to the electronics, BCs or EPSs also consist of a plastic enclosure, cords, and other 

mechanical components such as heat sinks or printed circuit boards. DOE expected the 

mechanical costs to remain constant at all CSLs and added these costs to the marked-up BOM, 

rather than applying a second markup. At this point, DOE applied an additional non-production 

markup to take into account shipping, handling, import duty, and corporate overheads. The result 

of this markup chain was the manufacturer selling price, which could serve as an input for 

further analyses. The exact markups DOE used in its determination analysis are described in 

depth in sections 5.4.6 and 5.4.12 of the draft technical report for BCs and EPSs, respectively. 

Even given small manufacturer markups, DOE recognizes that the manufacturer selling 

prices obtained using the above method are at best an upper bound on the true cost of production. 

Actual EPS prices are lower because EPS manufacturers typically bypass the distributor used to 

obtain the high-volume quote. They also often deal at higher volumes. In its preliminary 

analyses, DOE plans to incorporate additional data on high-volume parts costs, obtained directly 

from component manufacturers or electronics-industry analysts. DOE welcomes input on 

factory-direct parts costs at 500,000 pieces per year and 2,000,000 pieces per year, which DOE 

considers to be typical yearly volumes for single EPS and BC designs. Obtaining parts costs at 

two different volumes allows DOE to obtain a more accurate cost estimate at additional volumes 

through interpolation. 

Item 40 DOE seeks comments on this and other possible methods of determining and 

validating manufacturing costs. DOE is particularly interested in obtaining high-volume 

component costs and typical manufacturer markups applied to the bill-of-materials cost. 

Finally, DOE realizes that by testing and pricing commercially available EPSs and BCs 

according to the method described above, it will be able to validate manufacturer-supplied data 

only along the efficiency range from baseline to best-in-market. DOE cannot purchase and test 

devices to validate manufacturer estimates at the max-tech CSL, because by definition no 

products exist in the market beyond the best-in-market CSL. DOE is, however, exploring 

methods of simulating the performance and evaluating the cost of EPSs and BCs that can meet 

CSLs beyond best-in-market. 

Item 41 DOE welcomes comment on methods for simulating the performance of 

highly-efficient EPSs and BCs as a means of validating data provided by manufacturers. 

5.4 Proprietary Designs 

DOE will consider in its engineering and economic analyses all design options that are 

commercially available or present in a working prototype, including proprietary designs, that 

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6 

meet the screening criteria discussed in section 4. However, DOE will consider a proprietary 

design in the subsequent analyses only if it does not represent a unique path to a given efficiency 

level. If the proprietary design is the only approach available to achieve a given efficiency level, 

DOE will reject the efficiency level from further analysis, because the analytical results would 

appear to favor one manufacturer over others. If, on the other hand, a given energy-efficiency 

level can be achieved by a number of design approaches, including a proprietary design, DOE 

may examine the given efficiency level based on that design. DOE is sensitive to manufacturer 

concerns about proprietary designs and will take appropriate steps to maintain the confidentiality 

of any proprietary data manufacturers provide. These data will provide input to the competitive 

impacts assessment and other economic analyses. 

Item 42 Are there proprietary designs of which DOE should be aware for any of the 

BCs and EPSs under consideration in this rulemaking? If so, how should DOE acquire 

the cost data necessary for evaluating these designs? 

5.5 Outside Regulatory Changes Affecting the Engineering Analysis 

In conducting an engineering analysis, DOE considers the effects of regulatory burdens 

outside DOE’s statutory energy conservation standards rulemaking process that can affect the 

manufacturers of the covered equipment. Outside regulatory requirements can also affect the 

energy efficiency or energy consumption of the BCs and EPSs covered under this rulemaking. 

DOE will attempt to identify all such outside regulatory requirements that could affect the 

engineering analysis. The consideration of these requirements is closely related to the cumulative 

regulatory burden assessment that DOE will carry out as part of the manufacturer impact 

analysis. DOE will consider the comments received on the engineering analysis described in the 

preliminary TSD and make any necessary changes. The updated analysis will be presented in the 

NOPR TSD. 

Item 43 DOE seeks comments on regulatory burdens or changes that should be 

considered in the engineering analysis of BCs and EPSs. 

Item 44 DOE seeks comments on any other issues that could affect the engineering 

analysis. 

ENERGY USE AND END-USE LOAD CHARACTERIZATION 

The purpose of the energy-use and end-use load characterization is to identify how 

consumers use products and equipment, and thereby determine the energy-savings potential of 

energy-efficiency improvements. For BCs and EPSs, DOE’s analysis will focus on how end 

users operate BCs and EPSs with the consumer products they power. 

The energy-use and end-use load characterization, which is an input to the LCC and 

national impact analyses, will represent the typical energy consumption in the field. End-use load 

characterization for BCs and EPSs is comprised of usage profiles, which estimate the time a 

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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 also assumes that usage profiles will not change 

over the analysis period. 

Sections 6.2.1 and 6.3.1 of the draft technical report provide a detailed list of usage 

profiles for BC and EPS applications. 

Item 45 DOE seeks comments on the consumer usage profiles presented in sections 

6.2.1 and 6.3.1 of the draft technical report. DOE seeks alternate sources, databases, or 

methodologies for developing usage profiles. DOE also seeks comments on its 

assumption that the usage profiles do not vary over the analysis period. 

For most electrical appliances, energy consumption is determined by measuring the 

energy 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 energy drawn from mains into another application. Therefore, the traditional method of 

calculating energy consumption is not appropriate for measuring BC or EPS energy consumption 

rates, which are more accurately described using the amount of energy dissipated by these 

devices. 

6.1 Battery Charger Energy Use 

For the purposes of calculating energy consumption, DOE considers a BC to always be in 

one of the following four states: 

	 Active Mode: The existing DOE test procedure for BCs defines active mode as the 

condition in which the battery charger is connected to mains power; a battery is 

attached to the charger; and the battery is receiving the main charge, equalizing 

cells,28 and performing other one-time or limited-time functions necessary for 

bringing the battery to the fully charged state. (See appendix C); 

	 Maintenance Mode: The existing 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. (See appendix C); 

	 Standby Mode or No-Battery Mode: The existing DOE test procedure for BCs defines 

no-battery mode as the condition in which the battery charger is connected to mains 

power and no battery is attached to the charger. As EISA requires, DOE is revising its 

BC test procedure to address standby mode. In a separate rulemaking, DOE defined 

standby mode as equivalent to no-battery mode for BCs. (See 74 FR 13318); and 

28 Equalization is a strategy implemented by some chargers whereby the states of charge of all the cells in a battery 

are brought to the same level to prevent the voltage across any cells from inverting—and thereby damaging the 

cell—during deep discharge. 

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	 Unplugged Mode: Unplugged mode represents the state in which the battery charger 

is disconnected from mains power. No energy is consumed in this mode. 

Unit energy consumption represents the annual consumption of a BC attaining a 

particular CSL. DOE calculates unit energy consumption at each CSL for each representative unit 

by combining the usage profile with the energy consumption characteristics for each energyconsuming mode. For BCs, unit energy consumption is the sum of: 

(1)	 Charge Energy Consumption: The product of the number of 24-hour charge 

cycles per year and the 24-hour charge cycle energy consumption; 

(2)	 Maintenance Mode Energy Consumption: The product of the time spent in 

maintenance mode and the power drawn during maintenance mode; and 

(3)	 Standby Mode Energy Consumption: The product of the time spent in standby 

mode and the power drawn during standby mode. 

Based on comments from interested parties about the variability of charge time among 

different battery chargers and charging behavior among end-users, DOE is considering using 24­

hour cycles to uniformly account for energy consumption during battery-charging sessions. A 

24-hour cycle models the behavior of a user who allows 24 hours for a battery to recharge. The 

cycle encompasses time spent in active mode, and once the battery reaches full charge, any 

remaining time spent in maintenance mode. The users of certain products, such as handheld 

vacuums, may keep the battery connected to the charger for extended periods of time following a 

24-hour charge cycle. In these cases, the usage profile would account for additional time spent in 

maintenance mode, in addition to the time spent in maintenance mode as part of the 24-hour 

charge cycle. 

Item 46 DOE requests comments on the use of 24-hour charge cycles for estimating 

energy consumption for BCs in active mode. 

Figure 6.1 shows an example of an estimated usage profile for do-it-yourself (DIY) power 

tools that DOE created for its determination analysis. A manufacturer trade organization 

suggested this usage pattern as being typical for this product application. As the figure shows, 

over the course of a week, a DIY power tool will go through approximately three 24-hour charge 

cycles, for a total of 72 hours. Time in maintenance mode is also 72 hours, and DOE estimates 

that the DIY power tool will spend 24 hours in standby mode per week and no time in unplugged 

mode. This weekly usage profile was then extended over a year to give an annual usage profile. 

DOE seeks comments on the usage profiles of BC applications. To view the annual usage 

profiles of all BC applications DOE has analyzed to date, please see section 6.2 of the draft 

technical report. 

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Figure 6.1. DIY Power Tool Weekly Usage Profile in Hours 

Item 47 DOE requests comments on the methodology presented for calculating unit 

energy consumption. DOE also requests comments on the usage profiles detailed in 

section 6.2 of the draft technical report. 

6.2 External Power Supply Energy Use 

Unit energy consumption represents the annual consumption of an EPS attaining a 

particular CSL. DOE calculates unit energy consumption at each CSL by combining usage 

profiles, which describe the time a device spends in each mode in one year, and the energy 

consumed by the EPS in each mode of operation. 

6.2.1 EPS Usage Profiles 

For many applications, usage depends strongly on the individual user. To account for the 

variety of users and their associated usage profiles, DOE will develop multiple usage profiles 

where appropriate. DOE will then calculate a weighted-average usage profile based on an 

estimated distribution of user types. 

6.2.1.1 EPS Modes and Application States 

Normally, when evaluating usage and energy consumption for a device, it is sufficient to 

observe only the energy-consuming modes of that device. Because the function of EPSs is to 

power consumer product applications, however, evaluating the usage and energy consumption of 

the EPS also requires evaluating the usage and energy consumption of the application itself. 

To avoid confusion, when describing usage and energy consumption from the perspective 

of the application, DOE uses the term “application state.” In contrast, when describing usage and 

energy consumption from the perspective of the EPS, DOE uses the term “EPS mode.” 

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By definition 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. These states vary by the type of application. 

An EPS can be in active mode, no-load mode, off mode, or unplugged. Table 6.1.gives a 

summary of these modes. 

Table 6.1.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: EISA generally defines active mode 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.” EISA further defines active mode for 

EPSs as “the mode of operation when an external power supply is connected to the 

main electricity supply and the output is connected to a load.”(42 U.S.C.6291(36)(B)) 

	 Standby Mode or No-Load Mode: EISA describes 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 to a load.”(42 U.S.C. 6291(36)(D)) 

Accordingly, DOE revised its EPS test procedure to address standby mode. In a 

separate rulemaking proceeding published in the Federal Register on March 27, 

2009, (74 FR 13318), DOE defined standby mode as equivalent to no-load mode for 

EPSs. 

	 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.” Off Mode is discussed further in section 6.3. 

	 Unplugged Mode: Unplugged mode is the state when the EPS is disconnected from 

mains power. No energy is consumed in this state. 

Consider a usage profile for an inkjet computer printer. DOE identified the following 

application states for multifunction devices. In each of these application states the EPS is in 

active mode: 

	 Printing: Where the inkjet printer is on and performing one of its primary functions. 

	 Idle: Where the printer is on but not performing any printing tasks. 

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	 Off: Where the printer is off (whether by automatic shutdown or by a user-controlled 

on/off switch). 

As illustrated in Table 6.2, in each application state, the power demands of the inkjet 

printer differ, so the EPS must supply a different amount of power for each state the application 

is in. 

Table 6.2. Usage and Output Power of 40W EPS for Inkjet Computer Printer 

EPS Mode Application State Annual Usage 

(hours/year) 

Reasoning EPS Output 

Power (W) 

Active Printing 52 Device in operation for 1 hour 

per week, or roughly 10-15 

minutes a day (5-7 tasks) each 

day of a 5-day work week. 

32* 

Idle 1,606 Device left idle for ~30 hours 

per work week, or 6 hours per 

day for 5 days a week. 

9.1 

Off 7,102 Device turned off when not in 

use. 

6.2 

No Load Disconnected from 

EPS 

0 The EPS is never disconnected 

from the load but left 

connected to mains. 

0 

Unplugged Disconnected from 

EPS 

0 EPS is never disconnected 

from mains. 

0 

* DOE estimated EPS output power for printing to be 80 percent of nameplate output power. 

Usage profile derived from TIAX LLC, "U.S. Residential Information Technology Energy Consumption 

in 2005 and 2010." Prepared for U.S. Department of Energy March 2006. 

Item 48 DOE requests comments on the usage profiles for EPS applications detailed 

in section 6.3 of the draft technical report. 

6.2.2 EPS Power Consumption by Modes of Operation 

EPS power consumption is a function of three factors: the nameplate output power of the 

EPS, the efficiency of the EPS, and the consumption of the EPS when in no load mode. 

No-load mode power (PNL) 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, an associated no-load 

mode power is given. 

EPS power consumption during active mode varies as the power requirements of its load 

vary. Nameplate output power is the highest output power that an EPS is capable of delivering. 

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X 

4 

X 

3 

X 

2 

X 

DOE intends to use two different approaches to calculating EPS power consumption 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 (η) 

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 4 values (points 2, 3, 4, and 5 in 

Figure 6.2.) As such, power consumption is 

PCon = PIn – POut
 

where 

POut = PIn x η
 

or 

PIn = POut x (1/η) 

Therefore, 

PCon = POut x (1/η – 1) 

For example, an EPS delivering an output power of 10 watts at 75 percent efficiency 

would consume: 

PCon = 10 W x (1/0.75 – 1) = 3.33 W 

5 

Input Power 

1 

(0W, PNL) X 

0% 25% 50% 75% 100% 

Output Power (Percent of Nameplate) 

Figure 6.2. Example Measurements from an EPS Test Procedure 

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EERE-2008-BT-STD-0005 COMMENT 03
X 

4 

X 

3 

X 

2 

X 

(25% x PNameplate, 25% x [PNameplate / η]) 

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 

consumption. 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. 

Because of this situation, DOE does not intend to use the active-mode efficiency metric alone. 

Instead, DOE will calculate energy consumption in this region by interpolating between 

two known points: (1) the no load power consumption and (2) the active mode consumption at 

25 percent of nameplate output power. These are points 1 and 2 in Figure 6.3. At an output 

power of 25 percent, the energy consumed by the EPS is: PConsumed = POut x (1/η – 1). At an 

output power of 0 percent (no load mode), the energy consumed by the EPS is: PConsumed = PNL. 

Given these two known values, DOE assumed 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. 

5 

Input Power 

1 

(0W, PNL) X 

0% 25% 50% 75% 100% 

Output Power (Percent of Nameplate) 

Figure 6.3. Relationship Between EPS Input Power and Output Power at Five Loading 

Points 

DOE approximated 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: 

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m = ∆y/∆x 

m = [(25% x [PNameplate / η]) – PNL] / [(25% x PNameplate) – 0] 

Thus, for output power levels below 25 percent nameplate output power, the input power 

of the EPS is: 

PIn = {[(25% x [PNameplate / η]) – PNL] / [25% x PNameplate]} x POut + PNL 

Since 

PConsumed = PIn – POut
 

Then 

PConsumed = {[(25% x [PNameplate / η]) – PNL] / [25% x PNameplate]} x POut + PNL – POut 

Or 

PConsumed = ({[(25% x [PNameplate / η]) – PNL] / [25% x PNameplate]}-1) x POut + PNL 

DOE seeks comment on its proposed methodology for calculating energy consumption at 

output power levels below 25 percent of nameplate output power. 

6.2.3 Calculating EPS Energy Use 

Unlike most other consumer products using electricity, the energy consumption of an 

EPS cannot always be measured as the energy drawn from mains, since the function of an EPS is 

to deliver power for the operation of other end-use applications. DOE intends to calculate the 

energy consumption of an EPS (ECON) as the difference between energy drawn from mains (EIN) 

and the energy supplied to the end-use application (EOUT), or: 

ECON = EIN - EOUT 

Since energy measures power (P) multiplied by a duration of time (T), the following 

equation is used: 

PCON * T = (PIN – POUT) * T 

Factoring in the different EPS modes: 

PCON * TTOTAL = PCON-Active * TActive + 

PCON-No-Load * TNo-Load
 

Further factoring in application states: 

PCON * TTOTAL = PCON-Active1 * TActive1 + 

PCON-Active2 * TActive2 + 

PCON-Active3 * TActive3 + 

... 

PCON-No-Load * TNo-Load 

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Thus, to calculate the energy consumption of an EPS, DOE will combine the time values 

(from usage profiles) with power consumption values. 

In its determination analysis, DOE did not differentiate between energy consumption of 

the EPS power levels above and below 25% of nameplate output power. Instead, DOE estimated 

a capacity factor, which is a single value expressed as the time-averaged ratio of actual output 

power during active mode divided by the nameplate output power. Capacity factor is described 

in detail in section 6.3.2.3 of the draft technical report. DOE does not intend to use capacity 

factor in this rulemaking. Rather, DOE believes the methodology described in this framework 

document will more accurately model EPS energy consumption. DOE invites stakeholder 

comment on this matter. 

Section 6.3 of the draft technical report lists usage profiles and unit energy consumption 

estimates for the following EPS-powered applications: 

Camcorders Laptop computers 

Cordless telephones Portable audio players 

Digital cameras Portable gaming devices 

Flat panel monitors Portable video players 

Flatbed scanners Small liquid crystal display (LCD) TVs 

Ink-jet computer printers Telephone answering devices 

Local area network (LAN) equipment Wi-Fi access points 

Medical devices Wireless telephones 

Modems/fax modems 

Item 49 DOE requests comment on its proposed methodology for calculating energy 

consumption at each application state under EPS active mode. 

Item 50 DOE requests comments on its proposed methodology for calculating energy 

consumption at output levels below 25 percent of nameplate output power. 

6.3 Off-Mode Energy Consumption 

EISA directs DOE to consider off mode energy consumption and defines this mode as the 

state when a device is connected to a main power source and not providing any standby or active 

mode function. In a separate rulemaking, DOE established that off mode only applies to those 

BCs and EPSs that have manual on-off switches (see 74 FR 13318). 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. For EPSs, off mode is the condition 

in which the EPS is connected to mains power, the EPS is not attached to a load, and all switches 

on the device are in the off position. 

Because the inclusion of on-off switches on BCs and EPSs is uncommon and the 

frequency with which these switches are used is unknown, DOE assumes that the energy 

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EERE-2008-BT-STD-0005 COMMENT 03
 

7 

consumption of the device would be zero while in off mode. That is, DOE assumes that the onoff switch controls the power input to the device, and thus switching it off would completely 

disconnect the device from mains. Therefore, as a simplification, DOE is proposing to include 

any time the device spends in off mode as part of the time the device spends in unplugged mode. 

Item 51 DOE requests comments on its proposal to associate off mode with 

unplugged mode for the purposes of calculating energy consumption. DOE also requests 

comments on time spent in off mode, as well as power consumption while in off mode. 

PRODUCT PRICE DETERMINATION 

As stated in section 5, the purpose of the engineering analysis and product price 

determination is to understand the relationship between end-user price and efficiency for BCs 

and EPSs. Because DOE needs a retail (consumer) price for each efficiency level used in the 

LCC and PBP analysis and the national impact analysis, DOE will start with manufacturer 

selling price (MSP) estimates and study the distribution value chain for BCs and EPSs moving 

from manufacturer to end-user. From that analysis, which includes volume estimates and typical 

markups applied by interested parties in the distribution chain, DOE will then calculate a 

manufacturer-to-retail markup to convert MSP estimates to retail price estimates. DOE will also 

develop a sales tax estimate and apply it to the retail price estimates to arrive at end-user product 

prices. 

Component Manufacturers 

BC Manufacturers 

Consumer Product Retailers 

Consumers 

OEMs 

Component Manufacturers 

EPS Manufacturers 

Consumer Product 

Retailers 

Consumers 

OEMs EPS 

Distributors 

Battery Charger Distribution External Power Supply Distribution 

Figure 7.1. BC and EPS Distribution Networks 

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EERE-2008-BT-STD-0005 COMMENT 03
 

 

 

Figure 7.1 shows the paths that BCs and EPSs typically take to market. Section 3.3.1 

discusses this distribution network in more detail. DOE estimates MSPs in its engineering 

analysis. For EPSs, OEM markups are then applied to the MSPs to arrive at the price to the 

retailer. To estimate the OEM markups, DOE will use publicly available data on the gross 

margins of major manufacturers. For BCs, DOE does not intend to derive separate OEM 

markups, because a single company will typically manufacture both a BC and the end-use 

application it powers. 

DOE will estimate retailer markups using publicly available data on the gross margins of 

major retailers of electronic and electrical products. When applying the retailer markups to arrive 

at pre-tax consumer prices, DOE will consider that some fraction of BCs and EPSs are not sold 

through a retailer but sold directly from the OEM to consumers. 

The sales tax represents state and local sales taxes and is a multiplicative factor that 

increases the end-user product price. DOE will obtain information on state and local sales tax 

from the Sales Tax Clearinghouse.29 These data will be compiled to calculate a national, 

population-weighted average sales tax as well as a population-weighted average tax for each 

Census division. The national-level sales tax figures will be used in the LCC, PBP (both 

discussed in section 8), and NPV (section 10) analyses, while the Census division-level tax 

figures may be used in life-cycle cost subgroup analyses (section 11). 

DOE has created initial estimates of manufacturer-to-consumer markups for BCs and 

EPSs. These estimates, shown in Table 7.1 and Table 7.2, are based on assumptions about how 

BCs and EPSs are sold (i.e., product grouping and distribution channels). Chapter 7 of the draft 

technical report explains these underlying assumptions in detail. 

DOE has grouped BCs and EPSs as the tables show merely for convenience of 

presentation. DOE is not proposing product classes at this time. If DOE adopts different product 

classes in the preliminary analyses, it will develop new estimates of the distribution chain 

markups for those classes. Section 3.6 discusses product classes, and comments from interested 

parties on this issue are welcome. 

Table 7.1. BC Manufacturer-to-Consumer Markups 

Battery Voltage 

0 to ≤ 3 V >3 to ≤ 9 V > 9 V 

Slow Charging 

>9 V 

Fast Charging 

OEM Markup 1.00 1.00 1.00 1.00 

Retailer Markup 1.37 1.45 1.51 1.51 

Sales Tax 1.069 1.069 1.069 1.069 

Total Markup 1.46 1.55 1.61 1.61 

Note: Total markup equals the product of the three markups. Multiplying the manufacturer selling price by the total 

markup yields the consumer purchase price. Column groupings represent past analysis and are provided as 

examples; products may be grouped differently in future analyses. 

29 The Sales Tax Clearinghouse, Inc., was established in August 1999 to facilitate the calculation of sales and use 

taxes administered by the Nation’s 7,000 taxing authorities at the State, county, and city levels. Information on the 

Sales Tax Clearinghouse can be found at www.thestc.com. 

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8 

Table 7.2. EPS Manufacturer-to-Consumer Markups 

Nameplate Output Power 

0 to < 4 W ≥ 4 to ≤ 60 W > 60 W 

OEM Markup 1.43 1.43 1.36 

Retailer Markup 1.31 1.31 1.31 

Sales Tax 1.069 1.069 1.069 

Total Markup 2.00 2.00 1.90 

Note: Total markup equals the product of the three markups. Multiplying the manufacturer selling price by the total 

markup yields the consumer purchase price. Column groupings represent past analysis and are provided as 

examples; products may be grouped differently in future analyses. 

Take, for example, low-voltage BCs, whose battery voltage is less than or equal to 3 

volts. The manufacturer selling prices DOE used as inputs in its preliminary analysis for BCs 

represent the prices at which BCs are sold to retailers. Because there is no separate OEM 

markup, it appears as 1.00 in Table 7.1. DOE found that the principal retailers of products that 

incorporate low-voltage BCs have an average markup of 37 percent or 1.37. The Sales Tax 

Clearinghouse reported a national average sales tax of 6.9 percent or 1.069. Multiplying these 

markups gives a total markup of 46 percent, or 1.46, for low-voltage BCs. DOE used the same 

process to arrive at manufacturer-to-consumer markups for other BCs and for EPSs. Chapter 7 of 

the draft technical report provides additional detail, including the data from which DOE derived 

the preliminary markups. 

Item 52 DOE seeks comments on all aspects of the product price determination for 

BCs and EPSs, including assumptions about the percent of shipments passing through 

each distribution channel and the markups associated with each channel. 

LIFE-CYCLE COST AND PAYBACK PERIOD ANALYSES 

This section describes the Department of Energy (DOE)’s methodology for analyzing the 

economic impacts of possible energy efficiency standards on individual consumers. The effect of 

standards on individual consumers includes a change in operating expense (usually decreased) 

and a change in purchase price (usually increased). This section describes three metrics DOE 

uses in the consumer analysis to determine the effect of standards on individual consumers: 

	 Life-cycle cost (LCC) is the total consumer expense over the life of a product, 

including purchase expense and operating costs (including energy expenditures). 

DOE discounts future operating costs to the time of purchase, and sums them over the 

lifetime of the equipment; 

	 Payback period (PBP) measures the amount of time it takes customers to recover the 

assumed higher purchase price of more energy-efficient equipment through lower 

operating costs; and 

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	 Rebuttable payback period is built on a rebuttable presumption that an energy 

conservation standard is considered economically justified if “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)) 

DOE’s LCC and PBP analyses generate values that calculate the payback period for 

consumers of potential energy conservation standards, which include, but are not limited to, the 

three-year payback period contemplated under the rebuttable presumption noted above. 

However, DOE routinely conducts a full economic analysis that considers the full range of 

impacts, including those to the consumer, manufacturer, Nation, and environment, as required 

under 42 U.S.C. 6295(o)(2)(B)(i). The results of this analysis serve as the basis for DOE to 

definitively evaluate the economic justification for a potential standard level. 

Because the test procedures codified in 10 CFR Part 430, Subpart B, Appendices Y and Z 

measure the energy efficiency of BCs and EPSs, and not actual energy consumption, DOE must 

analyze the effect on consumers of BCs and EPSs by calculating the LCC and PBP using data 

from the engineering analysis (section 5), the energy-use and end-use load characterization 

(section 6), and the product price determination (section 7). 

When calculating the LCC, DOE discounts future operating costs to the time of purchase 

and sums them over the lifetime of the equipment, as shown in the following equation: 

N	 OCt LCC  IC   t 

t 1 1  r

where: 

LCC = life-cycle cost in dollars, 

IC = total installed cost in dollars, 

∑ = sum over the lifetime, from year 1 to year N, 

N = lifetime of product in years, 

OC = operating cost in dollars, 

r = discount rate, and 

t = year for which operating cost is being determined. 

For BCs and EPSs, DOE conducted some preliminary work on the LCC as part of its 

determination analysis directed by EPACT 2005. The text that follows discusses some of these 

inputs and methodologies that DOE was developing when the determination analysis was 

rescheduled. One of the initial decisions DOE made for the LCC was to focus the analysis on the 

use of BCs and EPSs in the residential sector, rather than the commercial or industrial sectors. 

The scope of coverage for these rulemakings encompasses BCs and EPSs designed for consumer 

products, such as cellular telephones, laptop computers, portable music players, digital cameras, 

power tools, hand-held vacuum cleaners, and so on. While DOE recognizes that commercial and 

industrial entities use these products, and the BCs and EPSs that power them, it believes that the 

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residential sector uses a considerable majority of the products in service today. For this reason, 

DOE is considering focusing its preliminary LCC analysis on the residential sector. 

Item 53 DOE seeks comments on its intention to focus its preliminary LCC analysis on 

the residential sector, and not the commercial or industrial sectors. 

8.1 Life-Cycle Cost and Payback Period Methodology 

For the draft determination analysis, DOE developed an LCC methodology based on the 

approach followed in other rulemakings, tailored for some unique aspects of BCs and EPSs. For 

example, while the equation above mentions “total installed cost” in its list of LCC input 

variables, DOE considers installation costs to be zero because they 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. Therefore, the total installed cost would be the retail price of the product paid by the 

consumer. 

Similarly, DOE considers repair and maintenance costs (which are typically associated 

with larger products and appliances) to be zero. In making this decision, DOE recognizes the 

reality of the marketplace, where the service life of a BC or EPS typically exceeds that of the 

consumer product with which it is designed to operate. A consumer would not incur repair or 

maintenance costs for a BC or EPS. Also, if a BC or EPS did fail, consumers would typically 

discard the device and purchase a replacement BC or EPS. 

In Figure 8.1, DOE presents its flow diagram for the draft determination analysis LCC 

developed in 2007. The figure depicts, from left to right, LCC inputs in yellow boxes, interim 

calculated values in green boxes, and final output values (i.e., LCC and PBP) in blue boxes. 

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Figure 8.1. Flow Diagram of Inputs for the Determination of LCC and PBP 

Under 42 U.S.C. 6295(o)(2)(B)(iii), the statute establishes a rebuttable presumption that a 

standard is economically justified “[i]f 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. . . .” 

DOE’s LCC and PBP analyses generate values that indicate the cost-effectiveness of products 

meeting potential energy conservation standards. These values include, but are not limited to, the 

3-year payback period contemplated under the rebuttable presumption test discussed above. 

However, DOE routinely conducts a full economic analysis that considers the full range of 

impacts, including those to the consumer, manufacturer, Nation, and environment, as required 

under 42 U.S.C. 6295(o)(2)(B)(i). The results of this full analysis serve as the basis for DOE to 

definitively determine the economic justification for a potential standard level (thereby 

supporting or rebutting the results of any preliminary determination of economic justification). 

DOE intends to conduct the preliminary LCC and PBP analyses using typical values for 

equipment retail price, operating life, electricity costs, electricity consumption, and discount 

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rates. If DOE determines that there is significant variability in any of these inputs, it will conduct 

sensitivity analyses to determine how the LCC and PBP are affected by high and low estimates 

of each input. For any sensitivity analyses that it conducts, DOE will account for correlations 

that may exist between inputs (e.g., electricity usage may be correlated to electricity prices). The 

detailed impact calculation, which DOE will conduct during the NOPR stage of the rulemaking, 

may include an assessment of impacts on subgroups of consumers, as described in section 11 of 

this framework document. 

For the NOPR, DOE will carefully review all the comments it receives on the preliminary 

LCC analysis, make any necessary revisions, and evaluate additional parameters not included in 

the preliminary analysis if necessary. 

8.2 Life-Cycle Cost and Payback Period Inputs 

As discussed above, DOE conducted some preliminary work in developing its LCC for 

the determination analysis. The LCC methodology described above and the inputs presented in 

Table 8.1 are based on approaches that DOE developed for other energy conservation standards 

rulemakings. The draft inputs are presented here for review and comment by interested parties. 

In its LCC analysis, DOE noted that BCs and EPSs are most commonly sold as 

components of consumer products. That is, the BC or EPS works as an enabling part of a system, 

converting mains electricity to charge a battery or operate a product. Thus, the retail price of a 

BC or EPS is bundled with the retail price of the consumer product (e.g., cellular telephone, 

laptop computer, digital camera). To determine appropriate retail prices for BCs and EPSs, DOE 

reviewed distributor catalogs and interviewed manufacturers familiar with the supply chain. As 

section 7 discusses, DOE used product price determination and supply chain markups to 

calculate product price inputs. These product prices (detailed in section 8.3.1 of the draft 

technical report) varied significantly depending on the capacity of the device and its efficiency. 

Table 8.1 presents the draft inputs that DOE developed in 2007 for the determination 

analysis. Section 8.3 of the draft technical report provides further detail on the derivation of and 

sources for these inputs. 

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Table 8.1. Draft Inputs to the Life-Cycle Cost and Payback Period Analyses 

Input Description Average or 

Typical Value 

Sources 

Product Price The retail price before tax (i.e., 

bundled with a consumer product). 

Based on a manufacturer selling 

price marked up through the 

distribution chain. 

Varies Distributor catalogs, high-volume 

price estimates, manufacturer 

interviews. 

Sales Tax Used to convert the product price to 

a final consumer retail price 

including sales tax. 

6.9% Weighted average of sales tax in 13 

geographic regions and large states. 

Unit Energy 

Consumption 

The annual on-site electricity 

consumption associated with a BC 

or EPS. 

Varies Developed in section 6, Energy-use 

and End-use Load 

Characterization. 

Electricity 

Prices 

The national residential sector 

average price per kilowatt-hour (i.e., 

$/kWh). 

$0.097/kWh in 

2005 

Energy Information Administration 

(EIA). 

Electricity 

Price Trends 

Projects changes in the price of 

electricity over the analysis period. 

Includes a high and low scenario. 

Varies The Annual Energy Outlook from 

the EIA. 

Product 

Lifetime 

The total years in use after which 

the consumer retires the BC or EPS 

from service. The BC or EPS may 

be retired before the end of its useful 

life if the consumer product it 

operates is retired from service. 

3 - 5 years Discussed in section 8.2.3. 

Discount Rate The rate DOE estimates to be 

representative of BC and EPS 

consumers, used to discount future 

expenditures and establish their 

present value. 

5.6% Weighted average of residential 

financing methods, discussed in 

section 8.2.2. 

Analysis 

Period 

The time period over which DOE 

calculates the LCC. 

Product lifetime Discussed in section 1.5. 

8.2.1 Electricity Prices 

For residential consumers of BCs and EPSs, DOE plans to use projections of national 

average electricity prices from Energy Information Administration's (EIA) Annual Energy 

Outlook (AEO) for the most recent year available. In other rulemakings, DOE has calculated a 

shipment-weighted average electricity price, based on inventories of products developed through 

the EIA’s Residential Energy Consumption Survey. However, the survey did not include 

questions on inventories of BCs and EPSs, and therefore, DOE is unable to create a national 

installed-base-weighted average electricity price. Instead, DOE proposes to use the national 

average electricity price, as published by EIA. 

To ascertain the sensitivity of the LCC to future electricity price trends, in addition to the 

reference case, DOE will evaluate the LCC using both the low and high economic growth cases. 

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Together, these three cases reflect the uncertainty in electricity prices over the analysis period. 

Figure 8.2 presents the residential electricity price trends (in constant 2007$), based on AEO 

2007 projections. Cents/kWh (2007$)

10.8 

10.7 

10.6 

10.5 

10.4 

10.3 

10.2 

10.1 

10.0 

9.9 

High
 

Low
 

Ref 

9.8 

2006 2008 2010 2012 2014 2016 2018 2020 2022 

Figure 8.2. AEO 2007 Residential Electricity Price Trend Forecast 

Item 54 DOE seeks comments on the use of the EIA national average electricity price 

and the AEO forecast of electricity prices over the analysis period. 

8.2.2 Life-Cycle Cost Discount Rates 

Discounting reflects the current value of money spent or saved in the future. As discussed 

previously, calculation of consumer LCC requires DOE to use a discount rate to determine the 

present value of the money the consumer would spend to operate the BCs and EPSs over the 

products’ lifetime. Because consumers can use a variety of financial means to purchase a BC or 

EPS, the discount rate should equal the average cost of capital to the consumer. DOE assumes 

these financial means, listed in Table 8.2, to be similar to the ones consumers use when 

purchasing and financing replacement appliances for the home. 

For the draft determination analysis, DOE acknowledged the similarity between 

households financing replacement appliances and purchasing BCs and EPSs, and therefore 

adapted the LCC discount rate derivation from the home appliances rulemaking to its draft 

analysis. DOE’s approach involved identifying all possible debt or asset classes that consumers 

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might use to purchase replacement equipment, including household assets that might be affected 

indirectly. 

DOE estimated the shares of the various debt and equity classes in the typical U.S. 

household portfolio using the Federal Reserve’s Survey of Consumer Finances (SCF) data for 

1989, 1992, 1995, 1998, 2001, and 2004. DOE also used SCF data to determine rates of return 

for each class. DOE then calculated an average rate weighted by the share of each class of debt 

or equity, equal to 5.6 percent, to represent a household discount rate. For more detail on the data 

sources, methodology, and calculation of the residential discount rate, please see section 8.3.4 of 

the draft technical report. 

Table 8.2. Shares and Interest or Return Rates Used for Household Debt and Equity Types 

Type 

Average Share of 

Household Debt Plus 

Equity (%)* 

Mean Real Effective 

Discount Rate (%)** 

Home equity loans 

Credit cards 

Other installment loans 

Other residential loans 

Other line of credit 

Checking accounts 

Savings and money market accounts 

Certificates of Deposit 

Savings bonds 

Bonds 

Stocks

3.6 

2.0 

1.7 

4.9 

0.5 

4.5 

15.7 

9.0 

1.5 

10.0 

 29.1 

4.0 

11.0 

6.0 

4.6 

8.7 

0.0 

2.3 

2.4 

3.5 

4.2 

8.8 

Mutual funds 17.5 7.0 

Total/weighted-average discount rate 100.0 5.6.0 

* Not including primary mortgage or retirement accounts.
 

** Adjusted for inflation and, for home equity loans, loan interest tax deduction.
 

Item 55 DOE seeks comments on the methodology to be used for calculating 

residential discount rate used in the LCC analysis. 

8.2.3 BC and EPS Operational Lifetimes 

DOE intends to use information from manufacturer product catalogs, various literature 

sources such as technical reports and conference proceedings, and input from manufacturers and 

other interested parties to establish BC and EPS lifetimes for use in the LCC and subsequent 

analyses. 

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As discussed earlier in this section, because BCs and EPSs are often made specifically for 

use with particular consumer products, 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 group of BCs and EPSs, 

DOE has gathered lifetime values for consumer product applications and combined them with 

shipment estimates to derive a shipment-weighted average lifetime representative of the group. 

Table 8.3 and Table 8.4 display the shipment-weighted average lifetimes that DOE derived 

during its preliminary work. These results are from DOE’s initial analysis and may change 

depending on the product classes used in the preliminary analysis. 

Table 8.3. Shipment-Weighted Average Lifetimes for Battery Chargers 

Battery Voltage 

0 to ≤ 3 V > 3 to ≤ 9 V > 9 V Slow 

Charging 

> 9 V Fast 

Charging 

Lifetime 3 years 5 years 5 years 5 years 

Table 8.4. Shipment-Weighted Average Lifetimes for External Power Supplies 

Nameplate Output Power 

0 to < 4 W ≥ 4 to ≤ 60 W > 60 W 

Lifetime 4 years 5 years 4 years 

To see the lifetimes of specific consumer product applications, please refer to section 

8.3.5 of the draft technical report. Based on consideration of the comments received on this 

framework document, DOE will make necessary changes to the analysis. These changes will be 

reflected in the preliminary TSD. 

Item 56 DOE seeks comments on appropriate lifetimes for the BCs and EPSs covered 

in this rulemaking. 

The following is a list of the sources of BC and EPS lifetime data DOE has identified to 

date: 

	 “30th Annual Portrait of the U.S. Appliance Industry.” Appliance Magazine. 

September 2007. 

	 U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy. 

“FY2005 Preliminary Priority-Setting Summary Report and Actions Proposed. 

Appendix A: FY2005 Technical Support Document. Table A9-1: Background Data 

on Battery Chargers and Power Supplies.” (Last accessed March 3, 2006.) 

www.eere.energy.gov/buildings/appliance_standards/pdfs/fy05_priority_setting_app_ 

a.pdf. 

	 TIAX LLC. “Assessment of Analyses Performed for the California Energy Efficiency 

Regulations for Consumer Electronics Products.” February 2006. TIAX LLC: 

Cambridge, MA. 

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Item 57 DOE seeks input on additional sources for the lifetimes of BCs and EPSs and 

comments on the application lifetimes provided in section 8.3.5 of the draft technical 

report. 

9 SHIPMENTS ANALYSIS 

DOE develops shipment forecasts of products to calculate the national impacts of 

standards on energy consumption, NPV, and future manufacturer cash flows. DOE plans to 

develop shipments forecasts based on an analysis of key market drivers for BCs and EPSs. 

Principal among these drivers is demand for the consumer products that use BCs and EPSs. 

9.1 Base Case Forecast 

To evaluate the various impacts of standards, DOE develops a base case shipments 

forecast against which it compares standards case shipments forecasts at higher CSLs. DOE will 

design the base case forecast to depict what it anticipates would happen to energy consumption 

and energy costs over time if energy conservation standards for the units covered under this 

rulemaking are not adopted. In determining the base case forecast, DOE will consider historical 

shipments, the mix of BC and EPS efficiencies currently sold, and how that mix might change 

over time if new standards are not adopted. For these purposes, DOE needs data on historical 

equipment shipments and the market shares of the different efficiency levels offered in each 

product class. 

In its work on the determination, DOE estimated that in 2007, 69,562,200 battery 

chargers and 397,200,000 external power supplies were sold in the United States. Using its data 

on total shipments of applications, DOE divided these shipments into groups according to 

voltage for BCs and nameplate output power for EPSs. To divide BC shipments into product 

groups, DOE used input from the Association of Home Appliance Manufacturers (AHAM) and 

the Power Tool Institute (PTI). DOE estimated distributions for EPSs based on the work of 

TIAX30 and the Darnell Group.31 Table 9.1 and Table 9.2 show the distribution of shipments by 

product grouping for BCs and EPSs. For a more detailed description of how DOE estimated 

shipments of BCs and EPSs, see chapter 9 of the draft technical report. 

30 TIAX LLC. Assessment of Analyses Performed for the California Energy Efficiency Regulations for Consumer 

Electronics Products. TIAX LLC: Cambridge, MA. February 2006. 

31 Darnell Group. External AC-DC Power Supplies: Global Market Forecasts and Competitive Environment. Second 

Edition. Darnell Group: Corona, CA. 2005. 

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Table 9.1. Battery Charger Shipments by Product Group in 2007 

 Battery Voltage 

 0 to ≤ 3 V > 3 to ≤ 9 V > 9 V Slow 

Charging 

> 9 V Fast 

Charging 

Shipments 

(millions) 5.14 41.71 11.36 11.36 

Table 9.2. External Power Supply Shipments by Product Group in 2007 

Nameplate Output Power 

0 to < 4 W ≥ 4 to ≤ 60 W > 60 W 

Shipments 

(millions) 112.2 249.5 35.5 

Item 58 DOE seeks recommendations on sources of data on shipments of BCs and 

EPSs by product group. 

DOE also hopes to understand the breakdown of efficiency levels within each group of 

BCs or EPSs on which analyses are performed (i.e., data on the distribution of shipments by 

efficiency). DOE is considering using the efficiency distributions shown in Table 9.3 for BCs 

and Table 9.4 for EPSs. Because very little information is available about the distribution of 

shipments by efficiency for BCs and EPSs, DOE reports these distributions with some 

uncertainty and encourages comments on alternative distributions. 

To estimate the distribution of BCs by efficiency, DOE based its analysis on a subset of a 

large dataset published by the California Energy Commission (CEC).32 

Table 9.3. Base Case Distribution of BC Shipments Across Efficiency Levels by Product 

Group in 2007 

Percentage of Market at 

Efficiency Level* 

Battery Voltage 

0 to ≤ 3 V > 3 to ≤ 9 V > 9 V Slow 

Charging 

> 9 V Fast 

Charging 

Baseline 

Slightly Improved 

CEC Tier 1/ENERGY STAR 

Beyond Standard 

Best-in-Market

60 

20 

13 

0 

7 

45 65 

13 10 

26 10 

10 15 

6 0 

65 

10 

10 

15 

0 

All Levels 100 100 100 100 

*Efficiency levels are discussed in section 5.2. 

To estimate the current year’s efficiency distribution of EPSs for its determination 

analysis, DOE used a Pacific Gas and Electric study. The study estimated that in 2004, 40 

32 Blosser, J., H. Kameth, et al. Battery Charger Laboratory Test Data File. California Energy Commission Public 

Interest Energy Research Funding. 2006. 

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EERE-2008-BT-STD-0005 COMMENT 03
 

percent of EPSs met CEC Tier 1 standards and 25 percent met CEC Tier 2 standards.33 DOE 

used these estimates and the EPA ENERGY STAR Qualified Products List to arrive at a 

distribution of EPS shipments across efficiency levels for each product group,34 discussed in 

depth in section 9.1.2 of the draft technical report. DOE recognizes that this information may be 

outdated and may change dramatically with the standards imposed by EISA. DOE seeks input on 

sources of current data on this subject. 

Table 9.4. Base Case Distribution of EPS Shipments Across Efficiency Levels by Product 

Group in 2007 

Percentage of Market at 

Efficiency Level* 

Nameplate Output Power 

0 to < 4 W ≥ 4 to ≤ 60 W > 60 W 

Baseline Linear 

Baseline Switched-Mode EPS 

CEC 1/ENERGY STAR 

CEC 2 

> CEC 2 

Market Best 

Max Tech 

35 

25 

15 

12 

10 

3 

0 

16 

44 

15 

6 

18 

1 

0 

0 

60 

15 

9 

5 

11 

0 

All Levels 100 100 100 

*Efficiency levels are discussed in section 5.2. 

DOE intends to use two approaches to characterize changes in efficiency of both BCs and 

EPSs over time in the absence of new standards. In the static approach, the efficiency 

distribution does not change over time in the absence of a new standard. In the dynamic 

approach, efficiency improves progressively over time, even after a new standard takes effect. 

DOE uses these two approaches to provide an upper and lower bound, respectively, for 

calculated energy savings from improvements in energy efficiency. These improvements may be 

spurred by changes in technology, voluntary programs such as the ENERGY STAR program, 

consumer preferences, and other market forces. See section 9.2 of the draft technical report for a 

more detailed discussion of DOE’s proposed approaches to forecasting changes in efficiency 

over time. 

Item 59 DOE seeks recommendations on sources of data that would provide accurate 

and up-to-date information on BC and EPS efficiency distributions within product 

groups. DOE also seeks comments on how it might characterize long-term trends in the 

efficiency of BCs and EPSs for its base case shipments forecasts. 

33 Fenstrom, Gary. “Codes and Standards Enhancement Initiative for PY2004: Title 20 Standards Development 

Analysis of Standards Options for Single-Voltage External AC to DC Power Supplies.” Prepared by Ecos 

Consulting, Davis Energy Group, and Energy Solutions for Pacific Gas and Electric. May 2004. 

34 Environmental Protection Agency. “Qualified Product (QP) List for ENERGY STAR® Ac-Dc Qualified External 

Power Supplies.” www.energystar.gov/ia/products/prod_lists/eps_ac_dc_prod_list.pdf. Accessed December 17, 

2007. 

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EERE-2008-BT-STD-0005 COMMENT 03
 

DOE intends to prepare shipment forecasts for the base case. The model will keep track 

of the aging and replacement of BCs and EPSs given product lifetimes (section 8.2.3) and a 

projection of future BC and EPS sales growth. The shipments growth rate for many applications 

using BCs and EPSs is quite high. This is especially true for higher-powered EPS applications. 

DOE is considering using the constant annual growth rates in Table 9.5 as reference values. 

However, as the market for these goods becomes more saturated, growth rates may slow. DOE 

seeks comments on whether growth rates that decline over time would be more appropriate and 

what those growth rates should be for purposes of DOE’s analysis. 

Table 9.5. Base Case Shipments Growth Rates for BCs and EPSs 

All BCs EPSs by Nameplate Output Power 

0 to < 4 W ≥ 4 and ≤ 60 W > 60 W 

Compound 

Annual Growth 

Rate (%) 

4 2 3 4 

Note: DOE may use separate growth rates for each BC product group. 

Item 60 DOE seeks comments on appropriate shipment growth rates. 

9.2 Standards Impacts on BC and EPS Shipments 

DOE will develop a set of shipment forecasts for each set of efficiency standards 

analyzed. These standards case forecasts will help DOE evaluate the impacts of standards on BC 

and EPS shipments and therefore on the energy consumption of BCs and EPSs. DOE derives 

standards case forecasts using the same data sets it used for the base case forecasts. However, 

because the standards case forecasts account for the increase in purchase price and the decrease 

in operating costs caused by standards, forecasted shipments typically deviate from the base 

case. The magnitude of the difference between the standards case and base case shipment 

forecasts depends on the calculated purchase price increase, as well as 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 drop in shipments relative to the base case. However, in the case of BCs and 

EPSs, the demand may be inelastic if the cost of BCs and EPSs does not increase much relative 

to the cost of the application. 

Another market response to the presence of a standard for BCs or EPSs is to substitute a 

different power source for the BC or EPS. Possible substitute sources may include internal power 

supplies, external power supplies (for BCs), primary batteries, rechargeable batteries (for EPSs), 

and USB systems, among others. The extent to which manufacturers choose substitute power 

sources may be limited by design constraints. For example, in some cases, using an internal 

power supply makes an application less portable. Another substitute, USB power, is limited 

because USB ports are much less common than traditional wall outlets. In its preliminary 

analysis, DOE assumed that the demand for BCs and EPSs is inelastic; that is, price increases in 

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the standards case lead to no decrease in demand for the product. DOE seeks comments on the 

price elasticity of demand for BCs and EPSs. 

Item 61 DOE seeks input on the sensitivity of BC and EPS demand to changes in 

price. 

In addition to quantifying the projected impact of standards on total shipments, DOE 

must also quantify the change in the mix of product efficiencies due to standards. DOE is 

considering two market reactions: shift and rollup. In the shift scenario, all products become 

more efficient in response to a standard, even those that were more efficient than the standard. In 

the rollup scenario, those products that do not meet the standard become just efficient enough to 

meet the standard but not exceed it, while the products that were already more efficient than the 

standard remain unaffected. These two standards case scenarios will be used in combination with 

the static and dynamic base case scenarios discussed above in section 9.1. See section 9.3 of the 

draft technical report for a more detailed discussion of DOE’s proposed approach to forecasting 

the effects of standards on shipments. 

Market-pull programs such as the ENERGY STAR program and consumer rebate 

programs that encourage the purchase of more efficient BCs and EPSs also affect standards case 

forecasts. When such programs exist, DOE will consider their impacts on shipments. 

Item 62 DOE seeks comments on how any new energy conservation standard for BCs 

and EPSs might affect shipments of these products. DOE specifically seeks comments on 

its rollup and shift scenarios, as discussed in section 9.3 of the draft technical report. 

10 NATIONAL IMPACT ANALYSIS 

The national impact analysis reflects DOE’s assessment of the aggregate impacts of 

potential efficiency standards at the national level. Measures of impact that DOE will report 

include future NES from CSLs (i.e., the combined incremental energy savings from a new or 

increased energy conservation standard relative to a base case of no change in the energy 

conservation national standard over a specified forecast period) and the NPV from CSLs (i.e., the 

combined incremental LCC from a new or increased energy conservation state relative to the 

base case over a specified forecast period). 

10.1 Inputs to Forecasts 

Analyzing impacts of Federal energy conservation standards for BCs and EPSs requires 

comparing projected energy consumption in the United States with and without new energy 

conservation standards. The forecasts contain projections of unit energy consumption of BCs and 

EPSs, annual shipments, the price of purchased units, and base case and standards case 

efficiencies. Section 6 discusses approaches to determine unit energy consumption while 

section 7 discusses approaches to determine retail prices for equipment. Section 9 discusses the 

derivations of the base case shipments forecasts. 

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Although improving the energy efficiency of a product would generally lead to lower 

energy consumption, DOE recognizes other factors that may impact energy consumption: 

	 Rebound Effect: Consumers who encounter lower operating costs associated with a 

more energy-efficient product frequently use that product more often than a less 

efficient product. This phenomenon is called the rebound effect. For BCs and EPSs, 

DOE expects the rebound effect to be negligible because consumers are unlikely to 

notice the decrease in operating costs that would result from new standards for these 

products. 

	 Associated Application Effect: BCs and EPSs are distinct from other consumer 

products regulated by DOE in that their energy consumption is directly tied to the 

usage of another end-use consumer product. Therefore changes in energy 

consumption, energy efficiency, or usage of that consumer product may affect the 

energy consumption of the BC or EPS. Because of the wide range of consumer 

products included and the absence of any known trend in how consumer product 

designers respond to more efficient power converters, DOE assumes this effect to be 

negligible. 

	 Consumer Awareness Effect: Increased awareness of the energy consumption of a BC 

or EPS in non-active modes may lead to consumers unplugging these devices when 

not in use. Conversely, decreased heating of the devices due to increased efficiency, 

may lead to lower perceived energy consumption and less consumer willingness to 

unplug devices when in standby mode. Because of the wide range of possible 

consumer reactions and no apparent trend in how consumers respond to more 

efficient power converters, DOE assumes the effects of individual consumer reactions 

would effectively cancel each other, leaving a negligible effect. 

Item 63 DOE seeks comments on the impact of the rebound effect, the associated 

application effect, and the consumer awareness effect on energy consumption of BCs and 

EPSs. To the extent that commenters can offer reasons and data supporting the adoption 

of a particular quantitative value for each of these effects, DOE is also interested in this 

information. 

Table 10.1 describes some of the major inputs DOE is anticipating it will develop for the 

national impact analysis. 

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Table 10.1. Inputs to the National Impact Analysis 

Input Data Description of Data Sources 

Shipments Annual shipments developed in section 9. 

Stock of BCs and EPSs This stock is calculated from the service life of BCs and EPSs 

developed in section 8 and annual shipments developed in section 9. 

Effective Date of Standard 2013 for Class A EPSs; TBD for BCs. 

Analysis Period 2013 to 2043 (30 years) for Class A EPSs; TBD for BCs. 

Base Case Forecasted Efficiency Distribution of base case shipments by efficiency level over time 

developed in section 9. 

Standards Case Forecasted Efficiency Distribution of shipments by efficiency level for each standards case 

over time developed in section 5.2. 

Unit Energy Consumption (kWh/yr) The average energy consumption of a BC or EPS established in the 

energy-use and end-use load characterization, section 6. 

Total Installed Cost Established in the Product Price Determination, section 7, and the LCC 

analysis, section 8. 

Electricity Price Forecast Established in the Life-Cycle Cost Analysis, section 8. 

Electricity Site-to-Source Conversion Conversion varies yearly and is generated by EIA Annual Energy 

Outlook forecasts of electricity generation and electricity-related losses. 

Discount Rate The discount rate is the rate at which DOE discounts future expenditures 

to establish their present value. To comply with OMB requirements, 

DOE will use 3 and 7 percent discount rates. 

Present Year Future costs and savings will be discounted to the year the analysis is 

performed. 

Rebound Effect The difference between the projected and actual savings due to 

increased efficiency. 

10.2 Calculation of National Energy Savings 

DOE intends to calculate NES for each year beginning with the expected effective date of 

the standards. DOE will calculate these savings as the difference in national electricity 

consumption between the base case and each CSL analyzed. DOE will perform this calculation 

using a spreadsheet model that effectively multiplies unit energy savings by the stock of 

equipment affected by standards. The National Inventory catalogs this stock of equipment. 

DOE determines unit energy savings by: 

	 calculating the weighted-average unit energy consumption (UEC) for a device in the 

base case, obtained by multiplying the UECs at each efficiency level by the base case 

forecasted efficiency; 

	 calculating the weighted-average UEC for a device in the standards case, obtained by 

multiplying the UECs at each efficiency level by the standards case forecasted 

efficiency; and 

	 calculating the difference between the UEC of the base case to the UEC of the 

standards case, with the difference representing the weighted-average UEC for a 

device in that year. 

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The National Inventory represents the rolling stock of EPSs and BCs through the analysis 

period. It is obtained by adding new shipments each year and removing units after their lifetime 

has passed. Because the efficiency of new units put in service each year can change over time, 

the inventory keeps track of the sales year (or vintage) of every unit. The savings generated by 

the BCs and EPSs of a given vintage accrue over several years. The national energy savings in a 

given year are actually the sum of the savings from multiple vintages of units. 

10.3 Net Present Value 

DOE determines the national NPV of energy conservation standards in conjunction with 

the NES. DOE calculates annual energy expenditures from annual energy consumption by 

incorporating forecasted energy prices using the shipment and average energy-efficiency 

forecasts described in section 9. DOE calculates annual equipment expenditures by multiplying 

the price per unit by the number of units in forecasted shipments. The difference between a base 

case and a standards case scenario gives the national energy bill savings and increased equipment 

expenditure in dollars. For the BCs and EPSs rulemakings, this differential will likely result in a 

NES offset against increased expenditures on BCs and EPSs. The difference each year between 

energy bill savings and increased equipment expenditures is the net savings (if positive) or net 

cost (if negative). 

DOE will discount these annual values to the present and sum them to provide an NPV. 

Since the national cost of capital may differ from the consumer cost of capital, the discount rate 

in the NIA can be different from the rate used in the LCC. Consistent with U.S. Office of 

Management and Budget (OMB) guidance, DOE will conduct two NPV calculations, one using a 

real discount rate of 3 percent and another using a real discount rate of 7 percent (OMB, Circular 

A-4: Regulatory Analysis, September 17, 2003). DOE considers the 7-percent and 3-percent real 

discount rates to be representative of the present value of costs and benefits associated with two 

types of investments facing an average degree of risk. Specifically, the 7-percent real value is an 

estimate of the average before-tax rate of return to private capital in the U.S. economy. The 3­

percent real value represents the “societal rate of time preference,” the rate at which society 

discounts future consumption flows to their present value. 

In calculating national NPV, DOE intends to use the same energy price forecasts it uses 

in the LCC. However, there is an important difference between the two analyses: in the LCC 

analysis, residential and commercial consumers are considered separately; however, estimates of 

national NPV must consider all consumers at once. Thus, DOE calculates national NPV using a 

weighted-average energy price forecast that considers the proportion of energy savings that 

accrue to each type of consumer. 

Item 64 DOE requests comments on the percent distribution of residential and 

commercial energy use for calculation of the weighted-average energy price. 

In response to comments by interested parties who asked for a simple, transparent model, 

DOE developed NES/NPV spreadsheet models for its standards rulemakings in 1996. These 

models project energy savings and demonstrate how to account for efficiency growth over 

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EERE-2008-BT-STD-0005 COMMENT 03
 

 

time.35 Although these models are specific to each product, their general framework is applicable 

to the BC and EPS markets. DOE expects that the NES/NPV spreadsheet modelsone for BCs 

and one for EPSswill provide stand-alone forecasts of NES and NPV. Based on the comments 

DOE receives on this framework document and the preliminary TSD, DOE will make any 

necessary changes to the analysis and incorporate those changes in the documentation for the 

NOPR. 

Item 65 DOE seeks comments on the NES/NPV spreadsheet models that DOE plans to 

use for estimating national impacts of energy conservation standards for BCs and EPSs. 

See chapter 10 of the draft technical report for a description of these models. 

11 LIFE-CYCLE COST SUBGROUP ANALYSIS 

At the NOPR stage of this rulemaking, DOE will conduct a life-cycle cost subgroup 

analysis. In this analysis, DOE analyzes consumer impacts by dividing consumers into 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 a variety of reasons, to be affected disproportionately 

by new or revised energy conservation standards (e.g., small businesses, ethnic minorities, lowincome or elderly consumers, etc.).36 The purpose of a subgroup analysis is to determine the 

extent of any such disproportional impact. DOE will work with interested parties early in the 

rulemaking process to identify any subgroups for this consideration. However, as noted above, 

DOE will not analyze the consumer subgroups until the NOPR stage of the analysis. 

In comparing potential impacts on the different consumer subgroups, DOE will evaluate 

variations in regional electricity prices, usage profiles, and installation costs that might affect the 

NPV of an energy conservation standard to certain consumer subgroups. To the extent possible, 

DOE will obtain estimates of the variability in each input factor and consider this variability in 

its calculation of consumer impacts. DOE will discuss with interested parties the variability in 

each input factor and likely sources of information. 

Item 66 DOE seeks comments on which consumer subgroups, if any, DOE should 

consider when developing standards for BCs and EPSs. 

35 Several examples of NES spreadsheet models from previous rulemakings can be found on DOE’s website at 

www.eere.energy.gov/buildings/appliance_standards. 36 For example, consumer subgroups with lower electricity prices than the average consumer will experience lower 

operating cost savings in the face of a standard, resulting in lower life-cycle cost savings. As another example, lowincome consumers may be disproportionately affected by standards that eliminate lower-cost products from the 

market. 

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12 MANUFACTURER IMPACT ANALYSIS 

As required by section 141 of EPACT 2005, DOE announced changes to the 

manufacturer impact analysis (MIA) approach in a report issued to Congress on January 31, 

2006, titled “Energy Conservation Standards Activities”37. Under this new approach, DOE will 

collect, evaluate, and report preliminary information and data on manufacturer impacts in the 

preliminary TSD. (See “Energy Conservation Standards Activities,” page 48.) Such preliminary 

information includes the anticipated conversion capital expenditures by efficiency level and the 

corresponding anticipated impacts on employment. DOE will seek further input on these issues 

during its manufacturer interviews for the preliminary analyses. 

The MIA is designed to assess the potential impacts of energy conservation standards on 

manufacturers of BCs and EPSs. In addition to financial impacts, a wide range of quantitative 

and qualitative effects may occur following adoption of a standard that may require changes to 

the manufacturing practices for these units. DOE will identify these effects through interviews 

with manufacturers and other experts. 

For the NOPR, DOE will supplement the results of the preliminary MIA conducted as 

part of the preliminary analyses with more detailed analyses (sections 12.1 through 12.5). 

Specifically, DOE will conduct an industry-wide cash-flow analysis using the Government 

Regulatory Impact Model (GRIM), identify and analyze subgroups of manufacturers whose 

business varies significantly from the industry as a whole, perform a competitive impacts 

assessment, and review the cumulative regulatory burden for the industry. 

12.1 Sources of Information for the Manufacturer Impact Analysis 

Many of the analyses described earlier provide important information that DOE will use 

as inputs for the manufacturer impact analysis. Such information includes financial parameters 

developed in the market assessment (section 3.1), retail price forecasts (section 7), and shipments 

forecasts (section 9). DOE will supplement this information with information gathered during 

manufacturer interviews. 

DOE will conduct detailed interviews with manufacturers to gain insight into the range of 

potential impacts from standards. The interview process plays a key role in the manufacturer 

impact analysis, because it provides an opportunity for directly affected parties to express their 

views on important issues. During the interviews, DOE will solicit information on the possible 

impacts on manufacturing costs, equipment prices, sales, direct employment, capital assets, and 

industry competitiveness. Both qualitative and quantitative information are valuable for this 

analysis. DOE will schedule interviews well in advance to provide every opportunity for key 

individuals to be available to participate. In addition, DOE will provide manufacturers with 

questionnaires before the interviews to facilitate information gathering. Although a written 

response to the questionnaire is acceptable, DOE prefers an interactive interview process, which 

helps clarify responses and provides the opportunity to identify additional issues. 

37 This report, titled “Energy Conservation Standards Activities” (Standards Activities), is available on the DOE 

website at www1.eere.energy.gov/buildings/appliance_standards/2006_schedule_setting.html. 

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DOE will ask interview participants to identify all confidential information provided in 

writing or orally. DOE also will determine whether the information submitted is entitled to 

confidential treatment. DOE will consider the information gathered, as appropriate, in the energy 

conservation standard decision-making process. DOE will also ask participants to identify any 

information that they wish to include in the public record, but that they do not want to have 

associated with their interview (thereby identifying that particular manufacturer). DOE will 

incorporate this information into the public record, but will report it without attribution. 

DOE will collate the interview results and prepare a summary of the major issues and 

outcomes. This summary will become part of the technical support document for this 

rulemaking. 

12.2 Industry Cash-Flow Analysis 

The industry cash-flow analysis will rely primarily on the GRIM. DOE uses the GRIM to 

analyze the financial impacts of new or more stringent energy conservation standards on the 

industry that produces the equipment covered by the standard. 

The GRIM analysis uses several factors—annual expected revenues; manufacturer costs 

such as costs of goods sold; selling, general, and administrative costs; taxes; and capital 

expenditures (both ordinary capital expenditures and those related to standards)—to determine 

annual cash flows associated with a new standard, beginning from the announcement of the 

standard and continuing for several years after its implementation. DOE compares the results 

against base case projections that involve no new standards. The financial impact of new 

standards is the difference between the two sets of discounted annual cash flows. Other 

performance measures, such as return on invested capital, are also available from the GRIM. 

DOE will gather the inputs needed for the GRIM from two primary sources: the analyses 

conducted to this point, and interviews with manufacturers and other interested parties. 

Information gathered from previous analyses will include financial parameters, manufacturing 

costs, price forecasts, and shipments forecasts. Interviews with manufacturers and other 

interested parties will be essential in supplementing this information. 

12.3 Manufacturer Subgroup Analysis 

Using average industry cost values may not adequately assess differential impacts among 

subgroups of BC or EPS manufacturers. DOE recognizes that smaller, more specialized, or other 

manufacturers exhibiting a cost structure that differs significantly from the industry average may 

be affected differently by the imposition of standards. Ideally, DOE would consider the impact 

on every firm individually. In highly concentrated industries, this may be possible. In industries 

having numerous participants, however, DOE uses the results of the market and technology 

assessment to group manufacturers into subgroups, as appropriate. For BCs and EPSs, DOE does 

not intend to assess the impacts on every manufacturer individually, and therefore is interested in 

feedback from interested parties about potential subgroups. 

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The detailed manufacturer subgroup impact analysis will entail calculating cash flows 

separately for each defined class of manufacturer. 

Item 67 DOE seeks comments on which potential subgroups of BC and EPS 

manufacturers should consider in its manufacturer subgroup analysis. 

12.4 Competitive Impacts Analysis 

EPCA directs DOE to consider any lessening of competition likely to result from an 

imposition of standards. (42 U.S.C. 6295(o)(2)(B)(i)(V)) It further directs the Attorney General 

to determine in writing the impacts, if any, of any lessening of competition. (42 U.S.C. 

6295(o)(2)(B)(ii)) 

DOE will make a determined effort to gather firm-specific financial information and 

impacts, and it will then report the aggregated impact of the standard on manufacturers. The 

competitive impacts analysis will focus on assessing the impacts on smaller, yet significant, 

manufacturers. DOE will base the assessment on manufacturing cost data and on information 

collected from manufacturer interviews. The interviews will focus on gathering information that 

would help in assessing asymmetrical cost increases to some manufacturers, increased proportion 

of fixed costs potentially increasing business risks, and potential barriers to market entry (e.g., 

proprietary technologies). DOE will provide the Attorney General with a copy of the NOPR for 

consideration in evaluating the potential competitive impact that standards would have. 

12.5 Cumulative Regulatory Burden 

Other regulations may apply to the BCs and EPSs covered under this rulemaking, and to 

other equipment produced by the same manufacturers. Multiple regulations may result in a 

significant, cumulative regulatory burden on these manufacturers. DOE will analyze and 

consider the impact on BC and EPS manufacturers of multiple, equipment-specific regulatory 

actions. 

Other regulations that could impact the industry affected by this rulemaking include: 

	 energy conservation standards for Class A EPSs established by the Energy 

Independence and Security Act of 2007 (EISA, Public Law 110-140); 

	 existing and/or proposed State standards for BCs and EPSs; and 

	 international standards, including upcoming regulation of EPSs and proposed 

regulation of BCs by Canada, Australia, and the European Union. 

Table 12.1 lists the national and international voluntary and regulatory programs for BCs 

and EPSs, including the voluntary ENERGY STAR specification in the United States and eight 

regulatory efforts internationally. Most of the regulatory programs are for EPSs only and follow 

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a structure similar to the ENERGY STAR EPS Version 1.1 specification. ENERGY STAR and 

Canada also address BCs. Appendix F provides a more complete discussion of these programs. 

Table 12.1 National and International Voluntary and Regulatory Programs for BCs and 

EPSs 

Country/Region Program/Institution BC EPS 

United States ENERGY STAR for BC and ENERGY STAR Tier I (V1.1) and 

Tier II (V2.0) for EPS 

X X 

Australia and New Zealand Minimum Energy Performance Standards (MEPS) AS/NZS 

4665:2005 

X 

Canada C381.1 for EPS and C381.2 for BC X X 

China China National Institute of Standardization (CNIS) and China 

Standard Certification Center (CSC) Standards 

X 

European Union Code of Conduct on Efficiency of External Power Supplies, EU 

Standby Initiative 

X 

European Union Eco-design of Energy-using Products (EuP) Initiative, Directive 

2005/32/EC 

X 

European Union (Subset of 

Member Countries) 

Group for Energy Efficient Appliances X 

Israel SI 4665.2 (AS/NZX 4665.2-2005) X 

Korea e-Standby Program X 

Item 68 DOE seeks comments on other existing and pending regulations it should 

consider in its examination of cumulative regulatory burden. 

13 UTILITY IMPACT ANALYSIS 

Like the life-cycle cost subgroup analysis, DOE completes the utility impact analysis 

during the NOPR stage of this rulemaking. In the utility impact analysis, DOE estimates the 

effects of energy conservation standards for BCs and EPSs on electricity sales for the electric 

utility industry. To quantify this impact, DOE plans to use a variant of EIA’s NEMS, called 

NEMS-BT. 38 NEMS is a large, multi-sectoral, partial-equilibrium model of the U.S. energy 

sector used primarily to prepare the AEO. NEMS-BT is a customized version of NEMS 

appropriate for the rulemaking analyses conducted by DOE’s Office of Building Technologies. 

NEMS-BT provides the reference case forecast for the United States through 2030 and is 

available to the public. 

The utility impact analysis compares the NEMS-BT model results for the base case and 

standards cases. Outputs of the utility impact analysis usually parallel results that appear in the 

latest AEO, with some additions. Typical outputs include forecasts of electricity generation, 

38 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 2000, 

DOE/EIA-0581 (March 2000). EIA approves the 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” refers to DOE’s Building Technologies Program, under whose aegis this work has been 

performed.) 

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sales, price, and avoided capacity. DOE plans to conduct the utility impact analysis as a scenario 

departing from the latest AEO reference case. In other words, DOE will model the energy 

savings impacts from energy conservation standards for BCs and EPSs using NEMS-BT to 

generate forecasts that deviate from the AEO reference case.39 

Item 69 DOE seeks input on its plans to use NEMS-BT to conduct the utility impact 

analysis. 

14 EMPLOYMENT IMPACT ANALYSIS 

DOE includes employment impacts among the factors it considers in selecting a proposed 

efficiency standard. DOE also considers the impact of CSLs on both direct and indirect 

employment. There is a general presumption40 against any CSL that would directly cause plant 

closures or significant loss of domestic employment unless specifically identified expected 

benefits of the standard would outweigh such adverse effects. (See the Process Rule, 10 CFR 

Part 430, Subpart C, Appendix A, sections 4(d)(7)(ii) and (vi), and 5(e)(3)(i)(B).) 

During the NOPR stage of the BC and EPS rulemakings, DOE will estimate the impacts 

of standards on employment for equipment manufacturers, relevant service industries, energy 

suppliers, and the economy in general. DOE’s analysis will cover both direct and indirect 

employment impacts. Direct employment impacts would result if standards led to a change in the 

number of employees at manufacturing plants and related supply and service firms. Direct 

impact estimates are covered in the manufacturer impact analysis. 

Indirect employment impacts are impacts on the national economy other than in the 

manufacturing sector being regulated. Indirect impacts may result both from expenditures 

shifting among goods (the substitution effect) and changes in income that lead to a change in 

overall expenditure levels (the income effect). DOE defines indirect employment impacts from 

standards as net jobs eliminated or created in the general economy as a result of increased 

spending, driven by the increased equipment prices and reduced spending on energy. 

DOE will investigate the combined direct and indirect employment impacts in the 

employment impact analysis using the “Impact of Sector Energy Technologies” (ImSET) model 

that Pacific Northwest National Laboratory (PNNL) developed for DOE’s Office of Planning, 

Budget, and Analysis. The model estimates the employment and income effects of energy-saving 

technologies in buildings, industry, and transportation. In comparison with simple economic 

39 Several NEMS-BT models from previous rulemakings can be found on the DOE’s Web site at 

www1.eere.energy.gov/buildings/appliance_standards. 

40 “(B) If the Department determines that a candidate standard level would be the direct cause of plant closures, 

significant losses in domestic manufacturer employment, or significant losses of capital investment by domestic 

manufacturers, that standard level will be presumed not to be economically justified unless the Department 

determines that specifically identified expected benefits of the standard would outweigh this and any other expected 

adverse effects.” (Emphasis added, 10 CFR Part 430, Subpart C, Appendix A, section 5(e)(3)(i)(B)). 

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multiplier approaches, ImSET allows for more complete and automated analysis of the economic 

impacts of energy-efficiency investments. Although DOE intends to use ImSET for its analysis 

of employment impacts, it seeks input on other tools and factors it might consider. 

Item 70 DOE seeks feedback on its planned approach for assessing direct and indirect 

national employment impacts. 

15 ENVIRONMENTAL ASSESSMENT 

DOE will prepare its draft environmental assessment (EA) pursuant to the National 

Environmental Policy Act and the requirements under 42 U.S.C. 6295(o)(2)(B)(i)(VI) and 

6316(a), to determine the environmental impacts of the amended standards. The intent of the 

environmental assessment is to provide emissions results estimates and to fulfill requirements to 

properly quantify and consider the environmental effects of all new Federal rules. 

The environmental assessment will focus on the impact of possible energy conservation 

standards on the significant pollutants and emissions of electricity-generating power plants. 

Specifically, the environmental assessment for this rulemaking will consider three types of 

energy-related emissions — oxides of nitrogen (NOx), mercury (Hg), and carbon dioxide (CO2). 

An additional emission, sulfur dioxide (SO2), was previously considered. However, DOE has 

determined that due to the presence of national caps on SO2 emissions as addressed below, any 

such reduction resulting from an energy conservation standard would not affect the overall level 

of SO2 emissions in the United States. 

DOE will estimate the reduction in total emissions of carbon dioxide (CO2) using the 

NEMS-BT computer model. DOE will calculate a range of estimates for reduction in NOx 

emissions and Hg emissions using current power sector emission rates. DOE will conduct each 

portion of the environmental impact analysis performed under this rulemaking as an incremental 

policy impact (i.e., an energy conservation standard for BCs and EPSs) of EIA’s AEO forecast, 

applying the same basic set of assumptions used in the latest version of AEO available for use in 

this analysis. Also, forecasts conducted with NEMS-BT consider the supply-side and demandside effects on the electric utility industry. Thus, DOE’s analysis will account for any factors 

affecting the type of electricity generation and, in turn, the amount of airborne emissions the 

utility industry generates. 

The NEMS-BT is run similarly to the AEO2008 NEMS, except the energy use is reduced 

by the amount of energy saved due to the CSLs. DOE obtains the inputs of national energy 

savings from the NIA spreadsheet model. For the Environmental Assessment, the output is the 

forecasted physical emissions. The net benefit of the standard is the difference between 

emissions estimated by NEMS-BT and the AEO2008 Reference Case. The NEMS-BT tracks 

CO2 emissions using a detailed module that provides results with a broad coverage of all sectors 

and inclusion of interactive effects. 

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Item 71 DOE seeks input on its plans to use NEMS-BT to conduct the environmental 

impact analysis on the equipment covered by this rulemaking. DOE is particularly 

interested in whether there are any other approaches to the environmental assessment that 

it should consider and the advantages and disadvantages for each of those approaches. 

The Clean Air Act Amendments of 1990 set an emissions cap on SO2 for all power 

generation. The attainment of this target, however, is flexible among generators and is enforced 

through the use of emissions allowances and tradable permits. Because SO2 emissions 

allowances have value, they will almost certainly be used by generators, although not necessarily 

immediately or in the same year regardless of whether a standard is in place. In other words, with 

or without a standard, total cumulative SO2 emissions will always be at or near the ceiling, while 

there may be some timing differences among yearly forecasts. Thus, it is unlikely that there will 

be an SO2 environmental benefit from standards as long as there is enforcement of the emissions 

ceilings. Although there may not be an actual reduction in SO2 emissions from electricity 

savings, there still may be an economic benefit from reduced demand for SO2 emission 

allowances. Electricity savings decrease the generation of SO2 emissions from power production, 

which can decrease the need to purchase or generate SO2 emissions allowance credits, and 

decrease the costs of complying with regulatory caps on emissions. 

NOx emissions are currently subject to emissions caps under the Clean Air Interstate Rule 

(CAIR) published in the Federal Register on May 12, 2005. 70 FR 25162 (May 12, 2005). The 

CAIR caps emissions in 28 eastern States and the District of Columbia (D.C.). As with the SO2 

emissions cap, energy conservation standards are not likely to have a physical effect on NOx 

emissions in those States. However, the standards created by a final rule that may result from 

this framework document might produce an environmentally related economic impact in the 

form of lower prices for emissions allowance credits if they were large enough. DOE believes 

that such standards would not produce such an impact because the estimated reduction in NOx 

emissions or the corresponding increase in available allowance credits in States covered by the 

CAIR cap would be too small to affect allowance prices for NOx. 

In contrast, new or amended energy conservation standards would reduce NOx emissions 

in those 22 States that are not affected by the CAIR, and these emissions could be estimated from 

NEMS-BT. As a result, DOE will use NEMS-BT to forecast emission reductions from any 

standards that DOE ultimately proposes in a NOPR for the products covered by this framework 

document. 

Though currently in effect, CAIR has been the subject of significant litigation. CAIR 

was vacated by the U.S. Court of Appeals for the District of Columbia Circuit (D.C. Circuit) in 

its July 11, 2008, decision in North Carolina v. Environmental Protection Agency.

41 However, 

on December 23, 2008, the D.C. Circuit decided to allow the CAIR to remain in effect until it is 

replaced by a rule consistent with the court's earlier opinion.42 

41 531 F.3d 896 (D.C. Cir. 2008)
 42 North Carolina v. EPA, 550 F.3d 1176 (D.C. Cir. 2008) (remand of vacatur). 

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Similar to SO2 and NOx, future emissions of Hg would have been subject to emission 

caps under the Clean Air Mercury Rule (CAMR). The CAMR would have permanently capped 

emissions of Hg for new and existing coal-fired plants in all States by 2010, but was vacated by 

the D.C. Circuit in its February 8, 2008, decision in New Jersey v. Environmental Protection 

Agency.

43 DOE typically uses the NEMS-BT model to calculate emissions from the electrical 

generation sector; however, the 2008 NEMS-BT model is not suitable for assessing mercury 

emissions in the absence of a CAMR cap. Thus, DOE plans to use a range of Hg emissions rates 

(in metric tons of Hg per energy terawatt hour (TWh) produced) based on the AEO2008. To 

estimate the reduction in mercury emissions, DOE will then multiply the emission rate by the 

reduction in coal-generated electricity associated with standards considered. 

Item 72 Because court actions have vacated the CAIR, DOE seeks input on how it 

should address NOx emissions in this rulemaking. 

Item 73 Because court actions have vacated the CAMR, DOE seeks input on how it 

should address Hg emissions in this rulemaking. 

DOE will calculate the possible monetary benefit of CO2, NOx, and Hg reductions. 

Cumulative monetary benefits will be determined using discount rates of 3 and 7 percent. DOE 

will monetize reductions in CO2 emissions due to the potential standards based on a range of 

monetary values drawn from studies that attempt to estimate the present value of the marginal 

economic benefits (based on the avoided marginal social costs of carbon) likely to result from 

reducing greenhouse gas emissions. The marginal social cost of carbon is an estimate of the 

monetary value to society of the environmental damages of CO2 emissions. This concept will be 

used rather than compliance costs because CO2 is not regulated. 

SO2 emissions have markets for emissions allowances. The market clearing price of SO2 

emissions is roughly the marginal cost of meeting the regulatory cap, not the marginal value of 

the cap itself. Further, because SO2 (for the nation) is regulated by a cap and trade system, the 

effect of the need to meet these caps is already included in the price of energy or energy savings. 

With a cap on SO2, the value of energy savings already includes the value of SO2 control for 

those consumers experiencing energy savings. The economic cost savings associated with SO2 

emissions caps is approximately equal to the change in the price of traded allowances resulting 

from energy savings multiplied by the number of allowances that would be issued each year. 

That calculation is uncertain because the energy savings for BCs and EPSs would most likely be 

so small relative to the entire electricity generation market that the resulting emissions savings 

would have almost no impact on price formation in the allowances market and likely would be 

outweighed by uncertainties in the marginal costs of compliance with the SO2 emissions caps. 

43 New Jersey v. EPA, 517 F.3d 574 (D.C. Cir. 2008). 

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Item 74 DOE invites comments on how to estimate such monetary values associated 

with emissions reductions or on any widely accepted values which might be used in DOE’s 

analyses. 

Item 75 DOE seeks input on other environmental factors to consider in this 

rulemaking. 

16 REGULATORY IMPACT ANALYSIS 

In the NOPR stage of this rulemaking, DOE will prepare a regulatory impact analysis. 

This analysis will address the potential for non-regulatory approaches to supplant or augment 

energy conservation standards to improve the efficiency of BCs and EPSs in the market. 

The regulatory impact analysis will consider the likely effects of non-regulatory 

initiatives on BC and EPS energy use, consumer utility, and life-cycle costs. DOE will account 

for the actual impacts of any existing initiatives to date, and consider historical information that 

may reasonably estimate the impacts of any such initiative in the future. DOE will use the NES 

spreadsheet model (section 10.2, “Calculation of National Energy Savings”) to calculate the NES 

and NPV for the alternatives to the potential conservation standards under consideration. 

As part of the regulatory impact analysis, and as discussed in section 12, “Manufacturer 

Impact Analysis,” DOE will identify and seek to mitigate the overlapping effects on 

manufacturers of new or revised DOE standards and other regulatory actions affecting the same 

products. This will include the collection of data on potential small manufacturer impacts or 

competitive disruptions that may result from any regulation. Furthermore, DOE will consider 

small business impacts on consumers in the life-cycle cost subgroup analysis, section 11. 

If DOE proposes energy conservation standards for BCs and EPSs and if the proposed 

rule constitutes a significant regulatory action, DOE will submit to OMB an assessment of costs 

and benefits required under section 6(a)(3) of Executive Order 12866, “Regulatory Planning and 

Review,” 58 FR 51735 (October 4, 1993). The Executive Order requires agencies to identify the 

specific market failure or other specific problem they intend to address that warrant new agency 

action, and also to assess the significance of that problem to help determine whether new 

regulation is warranted. (Executive Order 12866, section 1(b)(1)) Without a market failure, a 

regulation cannot result in net benefits. DOE seeks comments on the potential market failures 

discussed in section 3.1 of this framework document. 

Of course, there are likely to be external benefits resulting from the improved efficiency 

of BCs and EPSs that are not captured by the users of such equipment. These benefits include 

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

prices such as reduced emissions of greenhouse gases and reduced use of natural gas and oil for 

electricity generation. DOE seeks comments on the weight that it should give to these factors in 

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determining the maximum efficiency level at which the total benefits are likely to exceed the 

total burdens resulting from a DOE standard. 

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APPENDIX A – EPCA DIRECTIVES REGARDING BATTERY CHARGERS AND 

EXTERNAL POWER SUPPLIES 

This appendix lists the relevant statutory requirements under 42 U.S.C. 6291, 42 U.S.C. 

6293, and 42 U.S.C. 6295 that apply to BCs and EPSs. These requirements are drawn from 

sections 321, 323, and 325 of EPCA, as amended by section 135 of EPACT 2005 and sections 

301, 309, and 310 of EISA. 

EPCA 321 (42 U.S.C. 6291) 

(32) The term “battery charger” means a device that charges batteries for consumer products, 

including battery chargers embedded in other consumer products. 

[ * * * * *] 

(36) EXTERNAL POWER SUPPLY-

(A) IN GENERAL- 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. 

(B) ACTIVE MODE- The term “`active mode”' means the mode of operation when an 

external power supply is connected to the main electricity supply and the output is 

connected to a load. 

(C) CLASS A EXTERNAL POWER SUPPLY- 

(i) IN GENERAL- The term “`class A external power supply”' means a device 

that--

(I) is designed to convert line voltage AC input into lower voltage AC or 

DC output; 

(II) is able to convert to only 1 AC or DC output voltage at a time; 

(III) is sold with, or intended to be used with, a separate end-use product 

that constitutes the primary load; 

(IV) is contained in a separate physical enclosure from the end-use 

product; 

(V) is connected to the end-use product via a removable or hard-wired 

male/female electrical connection, cable, cord, or other wiring; and 

(VI) has nameplate output power that is less than or equal to 250 watts. 

(ii) EXCLUSIONS- The term “`class A external power supply”' 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. 

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(D) NO-LOAD MODE- The term ““no-load mode”” means the mode of operation when 

an external power supply is connected to the main electricity supply and the output is not 

connected to a load. 

[ * * * * *] 

(52) DETACHABLE BATTERY- The term “`detachable battery”' means a battery that is-- 

(A) contained in a separate enclosure from the product; and 

(B) intended to be removed or disconnected from the product for recharging. 

EPCA 323(b) (42 U.S.C. 6293(b)) 

(17) CLASS A EXTERNAL POWER SUPPLIES- Test procedures for class A external power 

supplies shall be based on the “Test Method for Calculating the Energy Efficiency of SingleVoltage External AC-DC and AC-AC Power Supplies” published by the Environmental 

Protection Agency on August 11, 2004, except that the test voltage specified in section 4(d) of 

that test method shall be only 115 volts, 60 Hz. 

EPCA 325 (42 U.S.C. 6295) 

(u) Battery charger and external power supply electric energy consumption 

(1)(A) Not later than 18 months after August 8, 2005, the Secretary shall, after providing 

notice and an opportunity for comment, prescribe, by rule, definitions and test procedures 

for the power use of battery chargers and external power supplies. 

(B) In establishing the test procedures under subparagraph (A), the Secretary shall - 

(i) consider existing definitions and test procedures used for measuring 

energy consumption in standby mode and other modes; and 

(ii) assess the current and projected future market for battery chargers and 

external power supplies. 

(C) The assessment under subparagraph (B)(ii) shall include – 

(i) estimates of the significance of potential energy savings from technical 

improvements to battery chargers and external power supplies; and 

(ii) suggested product classes for energy conservation standards. 

(D) Not later than 18 months after August 8, 2005, the Secretary shall hold a scoping 

workshop to discuss and receive comments on plans for developing energy 

conservation standards for energy use for battery chargers and external power 

supplies. 

(E) EXTERNAL POWER SUPPLIES AND BATTERY CHARGERS-44 

(i) ENERGY CONSERVATION STANDARDS- 

(I) EXTERNAL POWER SUPPLIES- Not later than 2 years after 

the date of enactment of this subsection, the Secretary shall issue a 

final rule that determines whether energy conservation standards 

44 The determination required under 49 U.S.C. 6295(u)(1)(E) is due December 19, 2009, which is two years after the 

enactment of this provision. 

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shall be issued for external power supplies or classes of external 

power supplies. 

(II) BATTERY CHARGERS- Not later than July 1, 2011, the 

Secretary shall issue a final rule that prescribes energy 

conservation standards for battery chargers or classes of battery 

chargers or determine that no energy conservation standard is 

technically feasible and economically justified. 

(ii) For each product class, any energy conservation standards issued 

under clause (i) shall be set at the lowest level of energy use that – 

(I) meets the criteria and procedures of subsections (o), (p), (q), (r), 

(s), and (t) of this section; and 

(II) would result in significant overall annual energy savings, 

considering standby mode and other operating modes. 

(2) The Secretary and the Administrator shall collaborate and develop programs 

(including programs under section 6294a of this title and other voluntary industry 

agreements or codes of conduct) that are designed to reduce standby mode energy use. 

(3) EFFICIENCY STANDARDS FOR CLASS A EXTERNAL POWER SUPPLIES­

(A) IN GENERAL- Subject to subparagraphs (B) through (D), a class A external 

power supply manufactured on or after the later of July 1, 2008, or the date of 

enactment of this paragraph shall meet the following standards: 

Active Mode 

Nameplate Output Required Efficiency 

(decimal equivalent of a percent-age) 

Less than 1 watt 0.5 times the Nameplate Output 

From 1 watt to not more than 51 watts 

The sum of 0.09 times the Natural 

Logarithm of the Nameplate Output 

and 0.5 

Greater than 51 watts 0.85 

No-Load Mode 

Nameplate Output Maximum Consumption 

No more than 250 watts 0.5 watts 

(B) NONCOVERED SUPPLIES- A class A external power supply shall not be 

subject to subparagraph (A) if the class A external power supply 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. 

(C) MARKING- Any class A external power supply manufactured on or after the 

later of July 1, 2008 or the date of enactment of this paragraph shall be clearly and 

permanently marked in accordance with the External Power Supply International 

Efficiency Marking Protocol, as referenced in the ‘“Energy Star Program 

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Requirements for Single Voltage External AC-DC and AC-AC Power Supplies, 

version 1.1’” published by the Environmental Protection Agency. 

(D) AMENDMENT OF STANDARDS- 

(i) FINAL RULE BY JULY 1, 2011-

(I) IN GENERAL- Not later than July 1, 2011, the Secretary shall 

publish a final rule to determine whether the standards established 

under subparagraph (A) should be amended. 

(II) ADMINISTRATION- The final rule shall-- 

(aa) contain any amended standards; and 

(bb) apply to products manufactured on or after July 1, 

2013. 

(ii) FINAL RULE BY JULY 1, 2015- 

(I) IN GENERAL- Not later than July 1, 2015 the Secretary shall 

publish a final rule to determine whether the standards then in 

effect should be amended. 

(II) ADMINISTRATION- The final rule shall-- 

(aa) contain any amended standards; and 

(bb) apply to products manufactured on or after July 1, 

2017. 

(4) END-USE PRODUCTS- An energy conservation standard for external power 

supplies shall not constitute an energy conservation standard for the separate end-use 

product to which the external power supplies is [sic] connected. 

[ * * * * *] 

(gg) Standby Mode Energy Use-

(1) DEFINITIONS-

(A) IN GENERAL- Unless the Secretary determines otherwise pursuant to 

subparagraph (B), in this subsection: 

(i) ACTIVE MODE- The term '“active mode'” means 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. 

(ii) OFF MODE- The term '“off mode'” means the condition in which an 

energy-using product--

(I) is connected to a main power source; and 

(II) is not providing any standby or active mode function. 

(iii) STANDBY MODE- The term '“standby mode'” means the condition 

in which an energy-using product--

(I) is connected to a main power source; and 

(II) offers 1 or more of the following user-oriented or protective 

functions: 

(aa) To facilitate the activation or deactivation of other 

functions (including active mode) by remote switch 

(including remote control), internal sensor, or timer. 

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(bb) Continuous functions, including information or status 

displays (including clocks) or sensor-based functions. 

(B) AMENDED DEFINITIONS- The Secretary may, by rule, amend the 

definitions under subparagraph (A), taking into consideration the most current 

versions of Standards 62301 and 62087 of the International Electrotechnical 

Commission. 

(2) TEST PROCEDURES-

(A) IN GENERAL- Test procedures for all covered products shall be amended 

pursuant to section 323 to include standby mode and off mode energy 

consumption, taking into consideration the most current versions of Standards 

62301 and 62087 of the International Electrotechnical Commission, with such 

energy consumption 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. 

(B) DEADLINES- The test procedure amendments required by subparagraph (A) 

shall be prescribed in a final rule no later than the following dates: 

(i) December 31, 2008, for battery chargers and external power supplies. 

(ii) March 31, 2009, for clothes dryers, room air conditioners, and 

fluorescent lamp ballasts. 

(iii) June 30, 2009, for residential clothes washers. 

(iv) September 30, 2009, for residential furnaces and boilers. 

(v) March 31, 2010, for residential water heaters, direct heating 

equipment, and pool heaters. 

(vi) March 31, 2011, for residential dishwashers, ranges and ovens, 

microwave ovens, and dehumidifiers. 

(C) PRIOR PRODUCT STANDARDS- The test procedure amendments adopted 

pursuant to subparagraph (B) shall not be used to determine compliance with 

product standards established prior to the adoption of the amended test 

procedures. 

(3) INCORPORATION INTO STANDARD- 

(A) IN GENERAL- Subject to subparagraph (B), based on the test procedures 

required under paragraph (2), any final rule establishing or revising a standard for 

a covered product, adopted after July 1, 2010, shall incorporate standby mode and 

off mode energy use into a single amended or new standard, pursuant to 

subsection (o), if feasible. 

(B) SEPARATE STANDARDS- If not feasible, the Secretary shall prescribe 

within the final rule a separate standard for standby mode and off mode energy 

consumption, if justified under subsection (o). 

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 (ii) APPLICATION DATE.—Section 327 [42 U.S.C. 6297] applies— 

(1) to products for which energy conservation standards are to be established under 

subsection (l), (u), or (v) of this section beginning on the date on which a final rule is 

issued by the Secretary, except that any State or local standard prescribed or enacted for 

the product before the date on which the final rule is issued shall not be preempted until 

the energy conservation standard established under subsection (l), (u), or (v) of this 

section for the product takes effect; and 

(2) to products for which energy conservation standards are established under subsections 

(w) through (hh) on August 8, 2005, except that any State or local standard prescribed or 

enacted before the date of enactment of August 8, 2005 shall not be preempted until the 

energy conservation standards established under subsections (w) through (gg) take effect. 

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APPENDIX B – DEFINITIONS 

This appendix provides statutory definitions relevant to BCs and EPSs. 

“Battery Charger” 

42 U.S.C. 6291(32) 

(32) The term "battery charger" means a device that charges batteries for consumer 

products, including battery chargers embedded in other consumer products. 

“External Power Supply” 

42 U.S.C. 6291(36)(A) 

(A) IN GENERAL- 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. 

“Class A External Power Supply” 

42 U.S.C. 6291(36)(C) 

(i) IN GENERAL- The term “`class A external power supply'” means a device that-- 

(I) is designed to convert line voltage AC input into lower voltage AC or DC 

output; 

(II) is able to convert to only 1 AC or DC output voltage at a time; 

(III) is sold with, or intended to be used with, a separate end-use product that 

constitutes the primary load; 

(IV) is contained in a separate physical enclosure from the end-use product; 

(V) is connected to the end-use product via a removable or hard-wired 

male/female electrical connection, cable, cord, or other wiring; and 

(VI) has nameplate output power that is less than or equal to 250 watts. 

(ii) EXCLUSIONS- The term “`class A external power supply'” 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. 

“Detachable Battery” 

42 U.S.C. 6291(52) 

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The term “`detachable battery'” means a battery that is-- 

(A) contained in a separate enclosure from the product; and 

(B) intended to be removed or disconnected from the product for recharging. 

“Consumer Product” 

42 U.S.C. 6291(1) 

The term “consumer product” means any article (other than an automobile, as defined in 

section 32901(a)(3) of title 49) of a type— 

(A) which in operation consumes, or is designed to consume, energy or, with 

respect to showerheads, faucets, water closets, and urinals, water; and 

(B) which, to any significant extent, is distributed in commerce for personal use 

or consumption by individuals; 

without regard to whether such article of such type is in fact distributed in commerce for 

personal use or consumption by an individual, except that such term includes fluorescent 

lamp ballasts, general service fluorescent lamps, incandescent reflector lamps, 

showerheads, faucets, water closets, and urinals distributed in commerce for personal or 

commercial use or consumption. 

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APPENDIX C – TEST PROCEDURES 

This appendix provides the DOE test procedures for measuring the energy consumption 

of BCs and EPSs, as contained in 10 CFR 430, Subpart B, Appendices Y and Z, respectively. 

These test procedures were published in the Federal Register on December 8, 2006 and amended 

by the standby and off mode final rule on March 27, 2009. 

Battery Chargers 

1. Scope: This appendix covers the test requirements used to measure battery charger energy 

consumption. 

2. Definitions: The following definitions are for the purposes of understanding terminology 

associated with the test method for measuring battery charger energy consumption.45 

Accumulated nonactive energy is the sum of the energy, in watt-hours, consumed by the battery 

charger in battery-maintenance mode and standby mode over time periods defined in the test 

procedure. 

Active mode is the condition in which the battery is receiving the main charge, equalizing cells, 

and performing other one-time or limited-time functions necessary for bringing the battery to the 

fully charged state. 

Battery or battery pack is an assembly of one or more rechargeable cells intended to provide 

electrical energy to a consumer product, and may be in one of the following forms: (a) 

detachable battery: a battery that is contained in a separate enclosure from the consumer product 

and is intended to be removed or disconnected from the consumer product for recharging; or (b) 

integral battery: a battery that is contained within the consumer product and is not removed from 

the consumer product for charging purposes. 

Battery energy is the energy, in watt-hours, delivered by the battery under the specified discharge 

conditions in the test procedure. 

Battery maintenance mode or maintenance mode is the mode of operation when the battery 

charger is connected to the main electricity supply and the battery is fully charged, but is still 

connected to the charger. 

Energy ratio or nonactive energy ratio means the ratio of the accumulated nonactive energy 

divided by the battery energy. 

Multi-port charger means a battery charger that is capable of simultaneously charging two or 

more batteries. These chargers also may have multi-voltage capability, allowing two or more 

batteries of different voltages to charge simultaneously. 

45 For clarity on any other terminology used in the test method, please refer to IEEE Standard 1515– 2000. 

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Multi-voltage a la carte charger means a separate battery charger that is individually packaged 

without batteries, and is able to charge a variety of batteries of different nominal voltages. 

Standby mode or no-load mode means the mode of operation when the battery charger is 

connected to the main electricity supply and the battery is not connected to the charger. 

3. Test Apparatus and General Instructions: The test apparatus, standard testing conditions, and 

instructions for testing battery chargers shall conform to the requirements specified in section 4, 

‘‘Standard Testing Conditions,’’ of the EPA’s ‘‘Test Methodology for Determining the Energy 

Performance of Battery Charging Systems,’’ December 2005 Incorporated by reference, see § 

430.22). The test voltage specified in section 4.1.1, ‘‘Voltage,’’ shall be 115 volts, 60 Hz. The 

battery charger should be tested using the full test methodology, which has a test duration of 48 

hours. In section 4.3.1, ‘‘Precision Requirements,’’ append this sentence to the end: ‘‘The test 

equipment must be capable of accounting for crest factor and frequency spectrum in its 

measurement of the UUT input current.’’ 

4. Test Measurement: (a) Inactive Mode Energy Consumption Measurement. The measurement 

of the battery charger energy ratio shall conform to the requirements specified in section 5, 

‘‘Determining BCS Energy Ratio,’’ of the EPA’s ‘‘Test Methodology for Determining the 

Energy Performance of Battery Charging Systems, December 2005’’ (Incorporated by reference, 

see § 430.22). 

(b) Active Mode Energy Consumption Measurement. [RESERVED] 

External Power Supplies 

1. Scope: This appendix covers the test requirements used to measure the active mode efficiency 

and the no-load energy consumption of external power supplies. 

2. Definitions: The following definitions are for the purposes of understanding terminology 

associated with the test method for measuring external power supply energy consumption.1 

Active mode is the mode of operation when the external power supply is connected to the main 

electricity supply and the output is connected to a load. 

Active mode efficiency is the ratio, expressed as a percentage, of the total real output power 

produced by a power supply to the real input power required to produce it. 

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. 

Single voltage external AC–AC power supply means an external power supply that is designed to 

convert line voltage AC input into lower voltage AC output and is able to convert to only one 

AC output voltage at a time. 

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Single voltage external AC–DC power supply means an external power supply that is designed to 

convert line voltage AC input into lower voltage DC output and is able to convert to only one 

DC output voltage at a time. 

Total harmonic distortion, expressed as a percent, is the RMS value of an AC signal after the 

fundamental component is removed and interharmonic components are ignored, divided by the 

RMS value of the fundamental component. 

True power factor is the ratio of the active (also referred to as real) power consumed in watts to 

the apparent power, drawn in volt-amperes. 

3. Test Apparatus and General Instructions: The test apparatus, standard testing conditions, and 

instructions for testing external power supplies shall conform to the requirements specified in 

section 4, ‘‘General Conditions for Measurement,’’ of the CEC’s ‘‘Test Method for Calculating 

the Energy Efficiency of Single-Voltage External AC–DC and AC–AC Power Supplies,’’ 

August 11, 2004. The test voltage specified in section 4.d, ‘‘Test Voltage,’’ shall only be 115 

volts, 60 Hz. 

4. Test Measurement: The measurement of the external power supply active mode efficiency and 

no-load energy consumption shall conform to the requirements specified in section 5, 

‘‘Measurement Approach,’’ of the CEC’s ‘‘Test Method for Calculating the Energy Efficiency 

of Single-Voltage External AD–DC and AC–AC Power Supplies,’’ August 11, 2004 

(Incorporated by reference, see § 430.22). 

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APPENDIX D – ENERGY INDEPENDENCE AND SECURITY ACT OF 2007 

On December 19, 2007, the President signed into law the Energy Independence and 

Security Act of 2007 (EISA 2007) (P.L. 110-140). This legislation amended certain aspects of 

EPCA, including, in particular, the potential amendment of existing testing requirements for BCs 

and EPSs (section 310 of EISA) and addition of mandatory efficiency standards for external 

power supplies (section 301 of EISA). 

SEC. 301. EXTERNAL POWER SUPPLY EFFICIENCY STANDARDS. 

(a) Definitions- Section 321 of the Energy Policy and Conservation Act (42 U.S.C. 6291) is 

amended-- 

(1) in paragraph (36)--

(A) by striking ”(36) The” and inserting the following: 

“(36) EXTERNAL POWER SUPPLY-

“(A) IN GENERAL- The”; and 

(B) by adding at the end the following: 

“(B) ACTIVE MODE- The term `active mode' means the mode of 

operation when an external power supply is connected to the main 

electricity supply and the output is connected to a load. 

“(C) CLASS A EXTERNAL POWER SUPPLY- 

“(i) IN GENERAL- The term `class A external power supply' 

means a device that-- 

“(I) is designed to convert line voltage AC input into lower 

voltage AC or DC output; 

”(II) is able to convert to only 1 AC or DC output voltage 

at a time; 

”(III) is sold with, or intended to be used with, a separate 

end-use product that constitutes the primary load; 

”(IV) is contained in a separate physical enclosure from the 

end-use product; 

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”(V) is connected to the end-use product via a removable or 

hard-wired male/female electrical connection, cable, cord, 

or other wiring; and 

”(VI) has nameplate output power that is less than or equal 

to 250 watts. 

“(ii) EXCLUSIONS- The term `class A external power supply' 

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. 

“(D) NO-LOAD MODE- The term `no-load mode' means the mode of 

operation when an external power supply is connected to the main 

electricity supply and the output is not connected to a load.”; and 

(2) by adding at the end the following: 

”(52) DETACHABLE BATTERY- The term `detachable battery' means a battery 

that is-­

”(A) contained in a separate enclosure from the product; and 

”(B) intended to be removed or disconnected from the product for 

recharging.”. 

(b) Test Procedures- Section 323(b) of the Energy Policy and Conservation Act (42 U.S.C. 

6293(b)) is amended by adding at the end the following: 

”(17) CLASS A EXTERNAL POWER SUPPLIES- Test procedures for class A external 

power supplies shall be based on the `Test Method for Calculating the Energy Efficiency 

of Single-Voltage External AC-DC and AC-AC Power Supplies' published by the 

Environmental Protection Agency on August 11, 2004, except that the test voltage 

specified in section 4(d) of that test method shall be only 115 volts, 60 Hz.”. 

(c) Efficiency Standards for Class A External Power Supplies- Section 325(u) of the Energy 

Policy and Conservation Act (42 U.S.C. 6295(u)) is amended by adding at the end the following: 

”(6) EFFICIENCY STANDARDS FOR CLASS A EXTERNAL POWER SUPPLIES120
 

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”(A) IN GENERAL- Subject to subparagraphs (B) through (D), a class A external 

power supply manufactured on or after the later of July 1, 2008, or the date of 

enactment of this paragraph shall meet the following standards: 

“Active Mode 

“Nameplate Output Required Efficiency 

(decimal equivalent of a percent-age) 

Less than 1 watt 0.5 times the Nameplate Output 

From 1 watt to not more than 51 watts 

The sum of 0.09 times the Natural 

Logarithm of the Nameplate Output 

and 0.5 

Greater than 51 watts 0.85 

“No-Load Mode 

“Nameplate Output Maximum Consumption 

No more than 250 watts 0.5 watts 

”(B) NONCOVERED SUPPLIES- A class A external power supply shall not be 

subject to subparagraph (A) if the class A external power supply 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. 

”(C) MARKING- Any class A external power supply manufactured on or after 

the later of July 1, 2008 or the date of enactment of this paragraph shall be clearly 

and permanently marked in accordance with the External Power Supply 

International Efficiency Marking Protocol, as referenced in the `Energy Star 

Program Requirements for Single Voltage External AC-DC and AC-AC Power 

Supplies, version 1.1' published by the Environmental Protection Agency. 

”(D) AMENDMENT OF STANDARDS- 

”(i) FINAL RULE BY JULY 1, 2011- 

”(I) IN GENERAL- Not later than July 1, 2011, the Secretary shall 

publish a final rule to determine whether the standards established 

under subparagraph (A) should be amended. 

”(II) ADMINISTRATION- The final rule shall-- 

”(aa) contain any amended standards; and 

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”(bb) apply to products manufactured on or after July 1, 

2013. 

”(ii) FINAL RULE BY JULY 1, 2015- 

”(I) IN GENERAL- Not later than July 1, 2015 the Secretary shall 

publish a final rule to determine whether the standards then in 

effect should be amended. 

”(II) ADMINISTRATION- The final rule shall-- 

”(aa) contain any amended standards; and 

”(bb) apply to products manufactured on or after July 1, 

2017. 

”(7) END-USE PRODUCTS- An energy conservation standard for external power 

supplies shall not constitute an energy conservation standard for the separate end-use 

product to which the external power supplies is connected.”. 

SEC. 309. BATTERY CHARGERS. 

Section 325(u)(1)(E) of the Energy Policy and Conservation Act (42 U.S.C. 6295(u)(1)(E)) is 

amended-- 

(1) by striking ”(E)(i) Not” and inserting the following: 

”(E) EXTERNAL POWER SUPPLIES AND BATTERY CHARGERS- 

”(i) ENERGY CONSERVATION STANDARDS- 

”(I) EXTERNAL POWER SUPPLIES- Not”; 

(2) by striking ”3 years” and inserting ”2 years”; 

(3) by striking ”battery chargers and” each place it appears; and 

(4) by adding at the end the following: 

”(II) BATTERY CHARGERS- Not later than July 1, 2011, the Secretary shall 

issue a final rule that prescribes energy conservation standards for battery 

chargers or classes of battery chargers or determine that no energy conservation 

standard is technically feasible and economically justified.”. 

SEC. 310. STANDBY MODE. 

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Section 325 of the Energy Policy and Conservation Act (42 U.S.C. 6295) is amended— 

(1) in subsection (u)— 

(A) by striking paragraphs (2), (3), and (4); and 

(B) by redesignating paragraphs (5) and (6) as paragraphs (2) and (3), 

respectively; 

(2) by redesignating subsection (gg) as subsection (hh); 

(3) by inserting after subsection (ff) the following: 

”(gg) Standby Mode Energy Use-

”(1) DEFINITIONS-

”(A) IN GENERAL- Unless the Secretary determines otherwise pursuant to 

subparagraph (B), in this subsection: 

”(i) ACTIVE MODE- The term `active mode' means 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. 

”(ii) OFF MODE- The term `off mode' means the condition in which an 

energy-using product— 

”(I) is connected to a main power source; and 

”(II) is not providing any standby or active mode function. 

”(iii) STANDBY MODE- The term `standby mode' means the condition 

in which an energy-using product— 

”(I) is connected to a main power source; and 

”(II) offers 1 or more of the following user-oriented or protective 

functions: 

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”(aa) To facilitate the activation or deactivation of other 

functions (including active mode) by remote switch 

(including remote control), internal sensor, or timer. 

”(bb) Continuous functions, including information or status 

displays (including clocks) or sensor-based functions. 

”(B) AMENDED DEFINITIONS- The Secretary may, by rule, amend the 

definitions under subparagraph (A), taking into consideration the most current 

versions of Standards 62301 and 62087 of the International Electrotechnical 

Commission. 

”(2) TEST PROCEDURES-

”(A) IN GENERAL- Test procedures for all covered products shall be amended 

pursuant to section 323 to include standby mode and off mode energy 

consumption, taking into consideration the most current versions of Standards 

62301 and 62087 of the International Electrotechnical Commission, with such 

energy consumption 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. 

”(B) DEADLINES- The test procedure amendments required by subparagraph 

(A) shall be prescribed in a final rule no later than the following dates: 

”(i) December 31, 2008, for battery chargers and external power supplies. 

”(ii) March 31, 2009, for clothes dryers, room air conditioners, and 

fluorescent lamp ballasts. 

”(iii) June 30, 2009, for residential clothes washers. 

”(iv) September 30, 2009, for residential furnaces and boilers. 

”(v) March 31, 2010, for residential water heaters, direct heating 

equipment, and pool heaters. 

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”(vi) March 31, 2011, for residential dishwashers, ranges and ovens, 

microwave ovens, and dehumidifiers. 

”(C) PRIOR PRODUCT STANDARDS- The test procedure amendments adopted 

pursuant to subparagraph (B) shall not be used to determine compliance with 

product standards established prior to the adoption of the amended test 

procedures. 

”(3) INCORPORATION INTO STANDARD-

”(A) IN GENERAL- Subject to subparagraph (B), based on the test procedures 

required under paragraph (2), any final rule establishing or revising a standard for 

a covered product, adopted after July 1, 2010, shall incorporate standby mode and 

off mode energy use into a single amended or new standard, pursuant to 

subsection (o), if feasible. 

”(B) SEPARATE STANDARDS- If not feasible, the Secretary shall prescribe 

within the final rule a separate standard for standby mode and off mode energy 

consumption, if justified under subsection (o).”; and 

(4) in paragraph (2) of subsection (hh) (as redesignated by paragraph (2)), by 

striking ”(ff)” each place it appears and inserting ”(gg)”. 

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APPENDIX E – LIST OF ITEMS FOR COMMENT 

This appendix lists all the items for comments contained in this framework document and 

the page numbers on which those items can be found. 

Item 1 DOE invites interested parties to review the draft technical report published in 

conjunction with this framework document and to provide comments on the analytical structure, 

inputs, and method DOE followed................................................................................................ 11 

Item 2 DOE welcomes comment from interested parties on differentiating between wall 

adapters and cradles. DOE also seeks comment on the type of circuitry (or lack thereof) typically 

contained in cradles....................................................................................................................... 14 

Item 3 DOE requests comment from interested parties on its interpretation of the Class A 

EPS exclusion of medical EPSs.................................................................................................... 17 

Item 4 DOE seeks comments on including DC-powered battery chargers within the scope of 

the BC standards analysis. ............................................................................................................ 18 

Item 5 DOE welcomes comment on any products with detachable batteries that are not 

motor operated, the wall adapters of which should also be excluded from Class A EPS standards. 

22 

Item 6 DOE requests comment on its interpretation of the definition of “detachable battery,” 

and the impact on EPSs excluded from Class A........................................................................... 22 

Item 7 DOE welcomes comment on ways of amending Approach B to make it consistent 

with the statutory language in EISA, or proposals of alternate approaches based on the clear BC 

and EPS divisions of the ENERGY STAR program. ................................................................... 32 

Item 8 DOE seeks comment on the prevalence of wall adapters for battery charging 

applications that may not be testable under the EPS test procedure............................................. 37 

Item 9 DOE seeks comments on the four approaches to interpreting the BC and EPS 

definitions to resolve ambiguities in the scope of the analyses. DOE is also interested in 

determining whether Approach B could be modified to permit its use in a manner consistent with 

the statutory framework created by Congress............................................................................... 38 

Item 10 DOE welcomes comment on additional functionality provided by some wall adapters 

for battery chargers that may impede their ability to meet the same standards as comparable wall 

adapters for other applications. DOE asks that commenters provide specific examples and 

suggest ways in which DOE can address any potential barriers that may arise. .......................... 38 

Item 11 DOE welcomes comment on the manufacturer burden of compliance with current 

EISA Class A EPS standards under each of the four approaches and seeks information on how 

DOE can minimize this burden while ensuring that the standards are being met consistently by 

the industry.................................................................................................................................... 38 

Item 12 DOE also welcomes comment on the likely manufacturer burden of compliance with 

possible future EPS and BC standards under each of the four approaches. To this end, DOE also 

seeks information from the industry regarding how the monitoring of compliance with these 

standards can be accomplished. .................................................................................................... 38 

Item 13 DOE is seeking input on these and any additional criteria it should consider in 

determining the presence of wall adapter charge control functions. ............................................ 39 

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Item 14 DOE welcomes comment on external characteristics (either physical or electrical) 

that can be used to identify a wall adapter performing charge control for determining compliance 

with the appropriate standard under Approaches A, C, and D, as well as the use of labeling to 

permit easy identification. How likely would it be that those requirements would be subject to 

potential manipulation by manufacturers? If manipulation is possible, what form, and in what 

context, would these activities likely occur? ................................................................................ 39
 

Item 15 DOE welcomes comment on the possible differences in distribution channels 

between wall adapters used for battery charging applications that do and do not have charge 

Item 16 DOE seeks comments on whether these and/or other factors influence the shipments 

Item 17 DOE seeks input on shipment data for BCs and EPSs and the applications that use 

them, including applications that use non-Class A EPSs (section 3.6.2). DOE also seeks input on 

Item 18 DOE invites interested parties to review and comment on domestic and foreign 

Item 19 DOE seeks comments and data from interested parties on these and other potential 

Item 20 DOE seeks comments on whether the 0.2 C charge-rate division between slow and 

fast chargers is appropriate and seeks detailed information regarding the typical charge rates for 

Item 21 Although DOE intends to revisit this issue in the future, its test procedure does not 

currently measure active-mode energy consumption. Nonetheless, DOE seeks comments on how 

Item 22 DOE seeks comments on how DOE could, in a future rulemaking, amend its BC test 

Item 23 DOE seeks comments on BC product class divisions, including whether battery 

voltage is the appropriate product classification criterion, and/or whether DOE should take into 

Item 24 DOE seeks comments on creating potential product class divisions for EPSs excluded 

Item 25 DOE seeks comments on whether to consider the presence of ICs or PFC circuitry in 

Item 26 DOE seeks comments on how to consider output voltage in developing product 

Item 27 DOE seeks comments on the possible approaches discussed concerning EPS product 

classes, and invites interested parties to propose alternative approaches and/or other factors DOE 

Item 28 DOE seeks comments on how the product classes it is considering for Class A EPSs 

may apply to non-Class A EPSs and whether there are particular issues DOE needs to take into 

Item 29 DOE seeks comments on all aspects of the product classes it is considering for BCs 

and EPSs, as well as any other methods for establishing product classes in accordance with the 

control functions. .......................................................................................................................... 41
 

of BCs and EPSs, and the extent to which each trend is likely to affect shipments..................... 42
 

the percentage of applications that are shipped with either a BC or an EPS................................ 43
 

efficiency programs relating to BCs and EPSs............................................................................. 44
 

market failures that may apply to BCs and EPSs. ........................................................................ 44
 

both categories of BCs.................................................................................................................. 47
 

it can best account for energy consumed during active mode. ..................................................... 50
 

procedure to measure energy consumption in active mode.......................................................... 50
 

account other factors, such as charge rate, battery capacity, or battery chemistry. ...................... 52
 

from the EISA definition of Class A............................................................................................. 53
 

developing product classes for EPSs. ........................................................................................... 56
 

classes, and how the low-voltage division should vary with EPS output power.......................... 56
 

should consider in developing product classes for the preliminary analyses. .............................. 56
 

account. 57
 

requirements of 42 U.S.C. 6295(q)............................................................................................... 57
 

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Item 30 DOE seeks comments on the preliminary technology options identified in this section 

and whether there are other technology options it should consider. In commenting on design 

options, please discuss their impacts, if any, on safety, performance, and consumer utility........ 59
 

Item 31 DOE seeks comments on how the four screening criteria might apply to the 

technology options discussed in section 3.7, as well as any additional technology option(s) that 

Item 32 DOE seeks comments on any consumer product applications which require use of a 

Item 33 DOE seeks recommendations on possible candidate standard levels to use when 

Item 34 DOE invites comments on the identification and selection of representative product 

classes and on models that may serve as good representative units within each product class. 

DOE also seeks comments on appropriate scaling relationships among product classes for both 

Item 35 DOE seeks comments on representative product classes and selection of 

Item 36 DOE seeks comments on the scaling of findings from representative product classes 

Item 37 DOE invites manufacturers to work with DOE in the interviews to help develop 

aggregated curves of manufacturer selling price versus efficiency for the various representative 

Item 38 DOE seeks comments on methods for normalizing cost and efficiency data provided 

by manufacturers for EPSs with output power and output voltage that differ from those of the 

Item 40 DOE seeks comments on this and other possible methods of determining and 

validating manufacturing costs. DOE is particularly interested in obtaining high-volume 

Item 41 DOE welcomes comment on methods for simulating the performance of highlyItem 42 Are there proprietary designs of which DOE should be aware for any of the BCs and 

EPSs under consideration in this rulemaking? If so, how should DOE acquire the cost data 

Item 43 DOE seeks comments on regulatory burdens or changes that should be considered in 

Item 44 DOE seeks comments on any other issues that could affect the engineering analysis.
 

an interested party recommends to DOE. ..................................................................................... 60
 

line-frequency EPS, and which could not accommodate use of a switched-mode EPS............... 61
 

analyzing EPSs and BCs............................................................................................................... 63
 

BCs and EPSs. .............................................................................................................................. 64
 

representative units from those representative product classes. ................................................... 65
 

to other product classes that DOE may not explicitly analyze. .................................................... 65
 

units. 66
 

representative units. ...................................................................................................................... 66
 

Item 39 DOE seeks comments on the shipment volumes to use for the representative units.. 66
 

component costs and typical manufacturer markups applied to the bill-of-materials cost........... 67
 

efficient EPSs and BCs as a means of validating data provided by manufacturers...................... 67
 

necessary for evaluating these designs?........................................................................................ 68
 

the engineering analysis of BCs and EPSs. .................................................................................. 68
 

68
 

Item 45 DOE seeks comments on the consumer usage profiles presented in sections 6.2.1 and 

6.3.1 of the draft technical report. DOE seeks alternate sources, databases, or methodologies for 

developing usage profiles. DOE also seeks comments on its assumption that the usage profiles 

do not vary over the analysis period. ............................................................................................ 69
 

Item 46 DOE requests comments on the use of 24-hour charge cycles for estimating energy 

Item 47 DOE requests comments on the methodology presented for calculating unit energy 

consumption for BCs in active mode............................................................................................ 70
 

consumption. DOE also requests comments on the usage profiles detailed in section 6.2 of the 

draft technical report..................................................................................................................... 71
 

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EERE-2008-BT-STD-0005 COMMENT 03
Item 48 DOE requests comments on the usage profiles for EPS applications detailed in 

section 6.3 of the draft technical report. ....................................................................................... 73
 

Item 49 DOE requests comment on its proposed methodology for calculating energy 

Item 50 DOE requests comments on its proposed methodology for calculating energy 

Item 51 DOE requests comments on its proposal to associate off mode with unplugged mode 

for the purposes of calculating energy consumption. DOE also requests comments on time spent 

Item 52 DOE seeks comments on all aspects of the product price determination for BCs and 

EPSs, including assumptions about the percent of shipments passing through each distribution 

Item 53 DOE seeks comments on its intention to focus its preliminary LCC analysis on the 

Item 54 DOE seeks comments on the use of the EIA national average electricity price and the 

Item 55 DOE seeks comments on the methodology to be used for calculating residential 

Item 56 DOE seeks comments on appropriate lifetimes for the BCs and EPSs covered in this 

Item 57 DOE seeks input on additional sources for the lifetimes of BCs and EPSs and 

Item 58 DOE seeks recommendations on sources of data on shipments of BCs and EPSs by 

Item 59 DOE seeks recommendations on sources of data that would provide accurate and upto-date information on BC and EPS efficiency distributions within product groups. DOE also 

seeks comments on how it might characterize long-term trends in the efficiency of BCs and EPSs 

Item 62 DOE seeks comments on how any new energy conservation standard for BCs and 

EPSs might affect shipments of these products. DOE specifically seeks comments on its rollup 

Item 63 DOE seeks comments on the impact of the rebound effect, the associated application 

effect, and the consumer awareness effect on energy consumption of BCs and EPSs. To the 

extent that commenters can offer reasons and data supporting the adoption of a particular 

Item 64 DOE requests comments on the percent distribution of residential and commercial 

Item 65 DOE seeks comments on the NES/NPV spreadsheet models that DOE plans to use 

for estimating national impacts of energy conservation standards for BCs and EPSs. See chapter 

Item 66 DOE seeks comments on which consumer subgroups, if any, DOE should consider 

Item 67 DOE seeks comments on which potential subgroups of BC and EPS manufacturers 

consumption at each application state under EPS active mode. ................................................... 77
 

consumption at output levels below 25 percent of nameplate output power................................ 77
 

in off mode, as well as power consumption while in off mode. ................................................... 78
 

channel and the markups associated with each channel. .............................................................. 80
 

residential sector, and not the commercial or industrial sectors. .................................................. 82
 

AEO forecast of electricity prices over the analysis period.......................................................... 86
 

discount rate used in the LCC analysis......................................................................................... 87
 

rulemaking. ................................................................................................................................... 88
 

comments on the application lifetimes provided in section 8.3.5 of the draft technical report.... 89
 

product group................................................................................................................................ 90
 

for its base case shipments forecasts............................................................................................. 91
 

Item 60 DOE seeks comments on appropriate shipment growth rates. ................................... 92
 

Item 61 DOE seeks input on the sensitivity of BC and EPS demand to changes in price....... 93
 

and shift scenarios, as discussed in section 9.3 of the draft technical report................................ 93
 

quantitative value for each of these effects, DOE is also interested in this information. ............. 94
 

energy use for calculation of the weighted-average energy price................................................. 96
 

10 of the draft technical report for a description of these models. ............................................... 97
 

when developing standards for BCs and EPSs. ............................................................................ 97
 

should consider in its manufacturer subgroup analysis. ............................................................. 100
 

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EERE-2008-BT-STD-0005 COMMENT 03
Item 68 DOE seeks comments on other existing and pending regulations it should consider in 

its examination of cumulative regulatory burden. ...................................................................... 101 

Item 69 DOE seeks input on its plans to use NEMS-BT to conduct the utility impact analysis. 

102 

Item 70 DOE seeks feedback on its planned approach for assessing direct and indirect 

national employment impacts. .................................................................................................... 103 

Item 71 DOE seeks input on its plans to use NEMS-BT to conduct the environmental impact 

analysis on the equipment covered by this rulemaking. DOE is particularly interested in whether 

there are any other approaches to the environmental assessment that it should consider and the 

advantages and disadvantages for each of those approaches...................................................... 104 

Item 72 Because court actions have vacated the CAIR, DOE seeks input on how it should 

address NOx emissions in this rulemaking.................................................................................. 105 

Item 73 Because court actions have vacated the CAMR, DOE seeks input on how it should 

address Hg emissions in this rulemaking.................................................................................... 105 

Item 74 DOE invites comments on how to estimate such monetary values associated with 

emissions reductions or on any widely accepted values which might be used in DOE’s analyses. 

106 

Item 75 DOE seeks input on other environmental factors to consider in this rulemaking. ... 106 

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APPENDIX F – OTHER MANDATORY AND VOLUNTARY ENERGY-EFFICIENCY 

STANDARDS FOR BCEPS 

F.1	 United States – ENERGY STAR for BC and ENERGY STAR Tier I (V1.1) and Tier 

II (V2.0) for EPS 

Revised U.S. ENERGY STAR levels became effective on November 1, 2008. These 

voluntary levels are stricter than V1.1 levels, and provide separate levels for standard vs. lowvoltage models and for AC/AC versus AC/DC models. 

Power converters covered under this standard include all single-voltage EPSs with 

nameplate output power up to 250 watts, and battery chargers for heat, light, and motion 

products with a 42-V limit and a 2-watt to 300-watt input limit. Notable exclusions to V1.1 are 

devices with detachable batteries, motor-operated devices, and medical devices. Notable 

exclusions to V2.0 are devices with batteries that attach directly. Exclusions to battery charger 

standards are inductive chargers and systems with additional functions. 

F.1.1 Current Standards 

 Version: Tier II v2.0 for EPS 

 Compliance: Voluntary 

 Effective: November 1, 2008 

Table F.1. U.S. ENERGY STAR Tier II for EPS Active-Mode Efficiency and No-Load 

Power: Standard Models 

Nameplate Output Power Minimum Efficiency in Active Mode 

0 < W ≤ 1 0.480 * Nameplate Output + 0.140 

1 < W ≤ 49 0.0626 * Ln(Nameplate Output) + 0.622 

49 < W 0.870 

Nameplate Output Power 

Maximum No-Load 

Power 

Consumption 

AC/AC 

Maximum No-Load 

Power 

Consumption 

AC/DC 

0 < W < 50 

≤ 0.50 W 

≤ 0.30 W 

50 ≤ W ≤ 250 ≤ 0.50 W 

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Table F.2. U.S. ENERGY STAR Tier II for EPS Active-Mode Efficiency and No-Load 

Power: Low-Voltage Models 

Nameplate Output Power 

Minimum Efficiency in Active Mode 

(Less than 6 Volts) 

0 < W ≤ 1 0.497 * Nameplate Output + 0.067 

1 < W ≤ 49 0.0750 * Ln(Nameplate Output) + 0.561 

49 < W 0.86 

Nameplate Output Power 

Maximum NoLoad Power 

Consumption 

AC/AC 

Maximum NoLoad Power 

Consumption 

AC/DC 

0 < W < 50 

≤ 0.50 W 

≤ 0.30 W 

50 ≤ W ≤ 250 ≤ 0.50 W 

 Version: ENERGY STAR for BC 

 Compliance: Voluntary 

 Effective: January 1, 2006 

Table F.3. ENERGY STAR Specifications for BC Maximum Nonactive Energy Ratio 

Nominal Battery Voltage 1.2 2.4 3.6 4.8 6.0 7.2 8.4 9.6 10.8 12.0 

Maximum Nonactive Energy Ratio 20.0 16.9 13.7 11.6 9.6 7.5 7.0 6.5 6.1 5.6 

Nominal Battery Voltage 13.2 14.4 15.6 16.8 18.0 19.2 20.4 21.6 22.8 ≥ 24 

Maximum Nonactive Energy Ratio 5.1 4.5 4.3 4.2 3.8 3.6 3.5 3.3 3.2 3.0 

*Energy Ratio is a function of maintenance mode power and no-load power. 

F.2	 Australia and New Zealand – Minimum Energy Performance Standards (MEPS) 

AS/NZS 4665:2005 

Administered by the Australian Greenhouse Office (AGO) through the National 

Appliance and Equipment Energy Efficiency Committee (NAEEEC), the Australian MEPS are 

mandatory. Voluntary higher efficiency levels exist, which will become the new MEPS in the 

future. 

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Power converters covered under this standard include all single-voltage EPSs with 

nameplate output power up to 250 watts. Notable exclusions are devices with batteries that attach 

directly, replacements, and medical devices. No-load power requirements only apply to AC/DC 

power supplies. 

The MEPS program does not yet deal with battery chargers, but if future standards were 

introduced, they would likely use the ENERGY STAR test method and MEPS, applying at 230 

Vac only. If specific MEPS are not introduced for battery chargers, the 1-watt standby proposal 

will apply. 

F.2.1 Current Standards 

 Version: MEPS for EPS 

 Compliance: Mandatory MEPS (Mark III), Voluntary High Efficiency (Mark IV and 

Mark V) 

 Effective: Australia - December 1, 2008, New Zealand – April 1, 2009 

Table F.4. Australia/New Zealand MEPS Levels for EPS Active-Mode Efficiency and NoLoad Power 

Nameplate Output Power Minimum Efficiency in Active Mode 

0 < W ≤ 1 0.49 * Nameplate Output 

1 < W ≤ 49 0.09 * Ln(Nameplate Output) + 0.49 

49 < W ≤ 250 0.84 

Nameplate Output Power Maximum No-Load Power Consumption 

0 < W < 10 ≤ 0.50 W 

10 ≤ W ≤ 250 ≤ 0.75 W 

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Table F.5. Australia/New Zealand High Efficiency Level IV for EPS Active-Mode 

Efficiency and No-Load Power 

Nameplate Output Power Minimum Efficiency in Active Mode 

0 < W ≤ 1 0.5 * Nameplate Output 

1 < W ≤ 51 0.09 * Ln(Nameplate Output) + 0.5 

51 < W ≤ 250 0.85 

Nameplate Output Power Maximum No-Load Power Consumption 

0 < W ≤ 250 ≤ 0.50 W 

Table F.6. Australia/New Zealand High Efficiency Level V for EPS Active-Mode Efficiency 

and No-Load Power 

Nameplate 

Output Power 

Minimum Efficiency in 

Active Mode – Less than 6 

Volts 

Minimum Efficiency in Active 

Mode – Greater than 6 Volts 

0 < W ≤ 1 0.497 * Nameplate Output + 

0.067 

0.480 * Nameplate Output + 

0.140 

1 < W ≤ 51 0.0750 * Ln(Nameplate 

Output) + 0.561 

0.0626 * Ln(N ameplate 

Output) + 0.622 

51 < W ≤ 250 0.86 0.87 

Nameplate 

Output Power 

Maximum NoLoad Power 

Consumption 

AC/AC 

Maximum No-Load 

Power 

Consumption 

AC/DC – Less than 

6 Volts 

Maximum NoLoad Power 

Consumption 

AC/DC – Greater 

than 6 Volts 

0 < W ≤ 51 

≤ 0.50 W 

≤ 0.30 W ≤ 0.30 W 

51 < W ≤ 250 ≤ 0.50 W No Maximum 

F.3 Canada – C381.1 for EPS and C381.2 for BC 

The Canadian Standards Association (CSA) is developing standards for external power 

supplies and battery chargers that are expected to become mandatory, which will require 

approval from Natural Resources Canada after the CSA has finalized the standards. 

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The proposed specifications for EPSs follow EISA levels, and scope. The specifications 

for BCs will likely follow CEC test procedures, levels, and scope. 

F.3.1 Current Standards 

 Version: Minimum Energy Performance Standards for EPSs 

 Compliance: Mandatory 

 Effective: Proposed September 1, 2009 for EPSs; awaiting comment from 

stakeholders. 2010 for BCs. 

Nameplate Output Power Minimum Efficiency in Active Mode 

0 < W ≤ 1 0.5 * Nameplate Output 

1 < W ≤ 51 0.09 * Ln(Nameplate Output) + 0.5 

51 < W ≤ 250 0.85 

Nameplate Output Power Maximum No-Load Power Consumption 

0 < W ≤ 250 ≤ 0.50 W 

F.4	 China – China National Institute of Standardization (CNIS) and China Standard 

Certification Center (CSC) Standards 

Designed and administered by the China National Institute of Standardization (CNIS) and 

the China Standard Certification Center (CSC), Chinese standards for external power supplies 

include both mandatory minimum efficiency levels and voluntary high-efficiency levels. 

Power converters covered under this standard include all single-voltage EPSs with 

nameplate output power up to 250 watts. Notable exclusions to the CSC standards are devices 

with batteries that attach directly. Battery charger standards do not exist but plans to draft them 

are in place, with consideration of modes beyond no-load mode. 

F.4.1 Current Standards 

 Version: CNIS levels 

 Compliance: Mandatory 

 Effective: Possibly 2009 

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Table F.7. CNIS MEPS for Active-Mode Efficiency and No-Load Power 

Nameplate Output Power Minimum Efficiency in Active Mode 

0 < W ≤ 1 0.39 * Nameplate Output 

1 < W ≤ 49 0.107 * Ln(Nameplate Output) + 0.39 

49 < W ≤ 250 0.82 

Nameplate Output Power Maximum No-Load Power Consumption 

0 < W < 10 ≤ 0.75 W 

10 ≤ W ≤ 250 ≤ 1 W 

 Version: CSC levels 

 Compliance: Voluntary 

 Effective: May 2005 

Table F.8. CSC Levels for Active-Mode Efficiency and No-Load Power (Same as ENERGY 

STAR Tier 1) 

Nameplate Output Power Minimum Efficiency in Active Mode 

0 < W < 1 0.49 * Nameplate Output 

1 ≤ W ≤ 49 0.09 * Ln(Nameplate Output) + 0.49 

49 < W ≤ 250 0.84 

Nameplate Output Power Maximum No-Load Power Consumption 

0 < W < 10 ≤ 0.50 W 

10 ≤ W ≤ 250 ≤ 0.75 W 

F.5	 European Union—Code of Conduct on Efficiency of External Power Supplies, EU 

Standby Initiative 

Developed and administered by the European Commission Joint Research Centre, the EU 

Code of Conduct is a voluntary agreement. Signatories to the Code of Conduct, which include 

major manufacturers of external power supplies, agree to meet active-mode efficiency and noload power consumption targets for at least 90 percent of their product lines. 

Power converters covered under this standard include all single-voltage EPSs and battery 

charger wall adapters with nameplate output power in the range 0.3 watts to 150 watts. The 

scope of the standard will be expanded in 2009 to include external power supplies with 

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nameplate output power up to 250 watts. Version 3 of the Code of Conduct includes a separate 

product class for cellular telephone EPSs, which is subject to different standards. 

F.5.1 Current Standards 

 Version: 2 

 Compliance: Voluntary 

 Effective: January 1, 2007 

Table F.9. EU Code of Conduct Version 2 Standards for EPS Active-Mode Efficiency and 

No-Load Power 

Nameplate Output Power Minimum Efficiency in Active Mode* 

0 to < 1 W 0.49 * Nameplate Output 

≥ 1 and ≤ 49 W 0.09 * Ln(Nameplate Output) + 0.49 

> 49 W to 150 W 0.84 

Nameplate Output Power Maximum No-Load Power Consumption 

≥ 0.3 W and < 60 W 0.30 W 

≥ 60 W and < 150 W 0.50 W 

* Power supplies that have a power factor correction (PFC) to comply with EN61000-3-2 (above 

75 W input power) have a 0.04 (4-percent) allowance. Therefore, the minimum on mode-load 

efficiency (100 percent or averaged) is relaxed to 0.80 (80 percent). 

F.5.2 Future Standards 

 Version: 3 

 Compliance: Voluntary 

 Effective: January 1, 2009 

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Table F.10. EU Code of Conduct Version 3 Standards for EPSs Excluding Cellular 

Telephone Adapters with Nameplate Output Power ≤ 8 Watts 

Nameplate Output Power Minimum Efficiency in Active Mode 

0 < W ≤ 1 0.44 * Pno + 0.145 

1 < W ≤ 36 [0.08 * ln(Pno)] + 0.585 

36 < W ≤ 250 0.870 

Nameplate Output Power Maximum No-Load Power Consumption 

> 0.3 W and < 50 W 0.30 W 

> 50 W and < 250 W 0.50 W 

Table F.11. EU Code of Conduct Version 3 Standards for Cellular Telephone Adapters 

with Nameplate Output Power ≤ 8 Watts 

Nameplate Output Power Minimum Efficiency in Active Mode 

> 0 W and < 1 W 0.50*Pno+0.029 

> 1 W and < 8 W [0.095*ln(Pno)]+0.529 

Nameplate Output Power Maximum No-Load Power Consumption 

> 0.3 W and < 8.0 W 0.25 W from 1.1.2009 to 31.12.2010 

> 0.3 W and < 8.0 W 0.15 W from 1.1.2011 

F.6	 European Union—Eco-design of Energy-using Products (EuP) Initiative, Directive 

2005/32/EC 

Developed and administered by the European Commission, the Eco-design of EuP 

Initiative is a mandatory directive. When complete, the directive will provide EU-wide rules for 

eco-design so that differences in national regulations do not present barriers to intra-EU trade. 

Minimum energy-efficiency requirements are among the product characteristics being addressed, 

including MEPS for external power supplies. 

Power converters covered under this standard include all single-voltage EPSs with 

nameplate output power up to 250 watts. Though battery chargers are not addressed, there are 

tentative plans for BC standards of 1 watt in off mode, enforced in 2009, dropping to 0.5 watt by 

2011. 

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F.6.1 Current Standards 

 Version: 1 

 Compliance: Mandatory 

 Effective: April 26, 2010 

Table F.12. EuP Version 1 Levels for EPS Active-Mode Efficiency and No-Load Power 

Nameplate Output Power Minimum Efficiency in Active Mode 

0 < W < 1 0.5 * Nameplate Output 

1 < W ≤ 51 0.09 * Ln(Nameplate Output) + 0.50 

51 < W ≤ 250 0.85 

Nameplate Output Power Maximum No-Load Power Consumption 

0 < W < 250 0.50 W 

F.6.2 Future Standards 

 Version: 2 for EPS 

 Compliance: Mandatory 

 Effective: April 26, 2011 

Table F.13. Version 2 Levels for EPS Active-Mode Efficiency and No-Load Power 

Nameplate 

Output Power 

Minimum Efficiency in 

Active Mode – Less than 6 

Volts 

Minimum Efficiency in Active 

Mode – Greater than 6 Volts 

0 < W ≤ 1 0.497 * Nameplate Output + 

0.067 

0.480 * Nameplate Output + 

0.140 

1 < W ≤ 51 0.0750 * Ln(Nameplate 

Output) + 0.561 

0.0626 * Ln(N ameplate 

Output) + 0.622 

51 < W ≤ 250 0.86 0.87 

Nameplate 

Output Power 

Maximum NoLoad Power 

Consumption 

AC/AC 

Maximum No-Load 

Power 

Consumption 

AC/DC – Less than 

6 Volts 

Maximum NoLoad Power 

Consumption 

AC/DC – Greater 

than 6 Volts 

0 < W ≤ 51 

≤ 0.50 W 

≤ 0.30 W ≤ 0.30 W 

51 < W ≤ 250 ≤ 0.50 W No Maximum 

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F.7 EU (Subset of Member Countries)Group for Energy Efficient Appliances 

Developed by the Group for Energy Efficient Appliances, which includes government 

agencies and institutions from Denmark, the Netherlands, Sweden, Switzerland, Germany, 

France, and Austria, the GEEA standards are voluntary. The purpose of the GEEA, organized in 

1996, is to harmonize national regulations pertaining to electronics and home office equipment. 

Minimum energy-efficiency requirements are among the product characteristics GEEA 

addresses, including MEPS for external power supplies and battery chargers. 

Power converters covered under this standard include all single-voltage EPSs with 

nameplate output power up to 150 watts. In addition to EPS and BC, this standard applies to 

portable personal equipment, which is defined as “equipment that is sold as part of a product 

with non-removable rechargeable batteries and is sold with the aim of recharging batteries.” 

F.7.1 Current Standards 

 Version: N/A 

 Compliance: Voluntary 

 Effective: 2007 

Table F.14. GEEA Levels for EPS and “Portable Personal Equipment” Active-Mode 

Efficiency and No-Load Power 

Nameplate Output Power Minimum Efficiency in Active Mode 

0 < W ≤ 1 0.49 * Nameplate Output 

1 < W ≤ 49 0.09 * Ln(Nameplate Output) + 0.50 

49 < W ≤ 150 0.84 

Nameplate Output Power Maximum No-Load Power 

Consumption* 

0 < W < 150 0.30 W 

* Includes Battery Chargers 

F.8 Israel – SI 4665.2 (AS/NZX 4665.2-2005) 

Administered by the Standards Institution of Israel (SII), the SI 4665.2 standards are a 

Hebrew translation of the AS/NZX 4665.2-2005 standards developed by Australia. These 

voluntary standards apply to external power supplies only. 

Power converters covered under this standard include all single-voltage EPSs with 

nameplate output power up to 250 watts. Notable exclusions are devices with batteries that attach 

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EERE-2008-BT-STD-0005 COMMENT 03
 

 

directly, replacements, and medical devices. The scope and test procedures are identical to those 

in the Australian standards (i.e., EPA EPS). 

F.8.1 Current Standards 

 Version: SI 4665.2 

 Compliance: Voluntary 

 Effective: December 2007 

Table F.15. SI 4665.2 Levels for EPS Active-Mode Efficiency and No-Load Power 

Nameplate Output Power Minimum Efficiency in Active Mode 

0 < W ≤ 1 0.49 * Nameplate Output 

1 < W ≤ 49 0.09 * Ln(Nameplate Output) + 0.49 

49 < W ≤ 250 0.84 

Nameplate Output Power Maximum No-Load Power Consumption 

0 < W < 10 ≤ 0.50 W 

10 ≤ W ≤ 250 ≤ 0.75 W 

F.9 Korea – e-Standby Program 

The e-Standby standards, developed and implemented by the Ministry of Commerce, 

Industry, and Energy (MOCIE) and Korea Energy Management Corporation (KEMCO), are 

voluntary. However, a presidential directive with mandatory standby power limits, similar to 

President George W. Bush's Executive Order 13221, is likely to be implemented by 2010. 

Power converters covered under this standard include all single-voltage EPSs with 

nameplate output power up to 150 watts and cellular telephone chargers. Notable exclusions are 

EPSs with charge circuitry. 

F.9.1 Current Standards 

 Version: N/A 

 Compliance: Voluntary 

 Effective: January 1, 2007 for EPS, January 1, 2006 for BC 

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Table F.16. e-Standby Program Levels for EPS Active-Mode Efficiency and No-Load 

Power 

Nameplate Output Power Minimum Efficiency in Active Mode 

0 < W ≤ 1 0.49 * Nameplate Output 

1 < W ≤ 49 0.09 * Ln(Nameplate Output) + 0.49 

49 < W ≤ 150 0.84 

Nameplate Output Power Maximum No-Load Power Consumption 

0 < W ≤ 10 ≤ 0.50 W 

10 < W ≤ 150 ≤ 0.75 W 

Table F.17. e-Standby Program Levels for Cellular Telephone Charger No-Load Power 

Maximum No-Load Power Consumption 

≤ 0.50 W 

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DRAFT TECHNICAL REPORT 

ENERGY CONSERVATION PROGRAM 

FOR CONSUMER PRODUCTS: 

Battery Chargers and External Power Supplies 

May 2009 

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 03
DRAFT TECHNICAL REPORT 

FRAMEWORK DOCUMENT 

BUILDING TECHNOLOGIES PROGRAM 

APPLIANCES AND COMMERCIAL EQUIPMENT STANDARDS 

BATTERY CHARGERS AND EXTERNAL POWER SUPPLIES 

CHAPTERS
 

CHAPTER 1 INTRODUCTION 

CHAPTER 2 MARKET ASSESSMENT 

CHAPTER 3 TECHNOLOGY ASSESSMENT 

CHAPTER 4 SCREENING ANALYSIS 

CHAPTER 5 ENGINEERING ANALYSIS 

CHAPTER 6 ENERGY USE AND END-USE LOAD CHARACTERIZATION 

CHAPTER 7 PRODUCT PRICE DETERMINATION 

CHAPTER 8 LIFE-CYCLE COST AND PAYBACK PERIOD ANALYSES 

CHAPTER 9 SHIPMENTS ANALYSIS 

CHAPTER 10 NATIONAL IMPACT ANALYSIS 

EERE-2008-BT-STD-0005 COMMENT 03
 

CHAPTER 1.INTRODUCTION 

1.1 Introduction...................................................................................................... 1-2 

1.2 Regulatory and Legislative History ................................................................. 1-2 

1.3 Overview of the Determination Analysis ........................................................ 1-3 

1.3.1 Components of a Determination Analysis Rulemaking........................... 1-3 

1.3.2 Overview of Determination Analysis Content.........................................1-4 

LIST OF FIGURES 

Figure 1.1. Flow Diagram of the Components of a Determination Analysis .................. 1-4 

1-1
 

EERE-2008-BT-STD-0005 COMMENT 03
1.1 Introduction 

The U.S. Department of Energy (DOE) Draft Technical Report presents the 

preliminary findings of DOE’s Determination Analysis for Battery Chargers (BCs) and 

External Power Supplies (EPSs), Docket No. EERE-2006-DET-0136. The purpose of the 

determination analysis, mandated by the Energy Policy and Conservation Act (EPCA), as 

amended by the Energy Policy Act of 2005 (EPACT 2005), was to determine whether 

energy conservation standards should be set for BCs and EPSs. DOE’s analysis was 

interrupted by passage of the Energy Independence and Security Act of 2007 (EISA 

2007). This report provides details of the work undertaken for the determination analysis 

until that point, and includes inputs, methods, and some draft outputs of the analysis. 

This report is published in conjunction with the “Energy Conservation Standards 

Rulemaking Framework Document for Battery Chargers and External Power Supplies,” 

which outlines the analytical process DOE will follow for the BC and EPS standards 

rulemaking over the next two years as a result of EISA 2007. This rulemaking may result 

in updated standards for EPSs and new standards for BCs by July 1, 2011. Unlike the 

framework document, this report presents a retrospective view of work already 

completed, and should not be construed as setting a precedent for future DOE action. 

Rather, DOE invites stakeholders to review the report and provide comments on all 

aspects of the draft analysis that are pertinent to the energy conservation standards 

rulemaking being initiated. 

This chapter describes the regulatory and legislative background for the 

determination analysis, explains the analytic process, and introduces the work described 

in detail in the body of the report. 

1.2 Regulatory and Legislative History 

DOE’s Appliances and Commercial Equipment Standards Program, within the 

Office of Energy Efficiency and Renewable Energy’s Building Technologies Program, 

develops and promulgates test procedures and energy conservation standards for 

consumer appliances and commercial equipment. 

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.” On August 8, 2005, the Energy Policy Act of 2005 (Pub. L. 109-58; 

EPACT 2005) amended sections 321 and 325 of EPCA, inserting definitions for BCs and 

EPSs and directing the Secretary of Energy to (1) establish test procedures, (2) hold a 

scoping workshop to discuss plans for developing energy conservation standards, and (3) 

conduct a determination analysis of 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, 71 FR 71340, on December 8, 2006, which included definitions and 

test procedures for BCs and EPSs. DOE codified a test procedure for BCs in title 10 of 

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EERE-2008-BT-STD-0005 COMMENT 03
 

 

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 notice of public 

meeting and availability of documentation for public review on December 29, 2006. 71 

FR at 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 was called a “Scoping Workshop” and was held on January 24, 2007. As 

required by EPACT 2005, the workshop focused on DOE’s plans for developing energy 

conservation standards for BCs and EPSs.1 

Complying with the third requirement, DOE initiated a determination analysis of 

energy conservation standards for BCs and EPSs in 2007, scheduled for completion in 

August 2008. However, on December 19, 2007, EISA 2007 (Docket No. EERE-2006-

DET-0136; Pub. L. 110-140) was enacted, amending sections 321, 323, and 325 of 

EPCA. These amendments required significant changes to the determination analysis 

DOE had been conducting on BCs and EPSs. As a result, work on the determination 

analysis was suspended. The details of the analytical process up to that point are detailed 

in this report. 

1.3 Overview of the Determination Analysis 

The purpose of the determination analysis rulemaking was to provide sufficient 

information to determine whether energy conservation standards should be set for BCs 

and EPSs. DOE’s determination and the possible establishment of energy conservation 

standards are two separate actions; however, the supporting analyses are similar. A full 

description of the analyses conducted as part of an energy conservation standards 

rulemaking can be found in the “Energy Conservation Standards Rulemaking Framework 

Document for Battery Chargers and External Power Supplies.” 

1.3.1 Components of a Determination Analysis Rulemaking 

Figure 1.1 summarizes the determination analysis process and presents the 

analytical components discussed in this report. Each component (represented by the 

boxes with dark numbers) had a set of “key inputs,” which represent the information 

required for the analysis. The numbers correspond to the chapter numbers where these 

analyses are found. The “approaches” column lists the methods used to obtain these 

inputs. For example, some key inputs existed in public databases, while others were 

collected from stakeholders or subject-matter experts. DOE developed the remaining 

inputs on its own. The “key outputs” column lists the results of each analysis, which feed 

1

 Information pertaining to the Scoping Workshop is available at 

www.eere.energy.gov/buildings/appliance_standards/residential/battery_external.html. 

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directly into the rulemaking. The arrows indicate the flow of information between the 

various analyses. 

Approaches Key Inputs* Analyses* Key Outputs 

Market and Technology 

Assessment 

Screening Analysis 

Engineering Analysis 

Markups for 

Equipment Price 

Determination 

Energy Use and 

End-Use Load 

Characterization 

Shipments 

Analysis 

Life-Cycle Cost and 

Payback Period 

Analysis 

National Impact 

Analysis 

• 

• Product Classes 

Market Structure 

• Design Options 

• Cost-Efficiency Relationship 

• Life-Cycle Costs 

• Payback Periods 

• National Energy Savings 

• Net Present Value 

• Characterize Industry 

• Analysis of Market Data 

• Market Segmentation 

• Non-Regulatory Programs 

Determination Analysis 

• Efficiency Level Approach 

• Design Option Approach 

• Product Prototypes 

• Energy Prices 

• Installation Costs 

• Maintenance & Repair Costs 

• Accounting Approach: 

Backcast and Forecast; 

Market Saturation 

• Identify Firms/Products 

• Define Distribution Channels 

• Economic Census Data 

Analysis 

• Retail Price Collection and 

Analysis 

Design Options 

Retail Prices 

Design Energy 

4 

5 

6 

7 

8 

9 

10 

• Efficiency/Performance 

• Manufacturing Cost 

• UEC 

• Energy Prices 

• Analysis of Energy Use Data 

• Energy Efficiency Levels 

• Historical Shipments 

Product Classes Technology Options 

Energy 

Efficiency 

Levels 

Annual Energy Use 

• Analysis of Product Data 

• Candidate 

Standard 

Levels 

• Installation Costs 

• Maintenance Costs 

• Repair Costs 

• Energy Price Forecasts 

• Site-to-Source Factors

 2, 3 

* Dark boxes indicate Determination Analysis chapters. 

Figure 1.1. Flow Diagram of the Components of a Determination Analysis 

1.3.2 Overview of Determination Analysis Content 

The BC and EPS determination analysis included a market and technology 

assessment, screening analysis, engineering analysis, energy-use and end-use load 

characterization, markups for equipment price determination, life-cycle cost (LCC) and 

payback period analysis, shipments analysis, and national impact analysis (NIA). As 

described in the framework document, DOE may use the work conducted during the 

determination analysis as a basis for the analyses it conducts during the energy 

conservation standards rulemaking process. 

Chapters 2 and 3 present the market and technology assessments, respectively, for 

BCs and EPSs. These chapters outline the typical consumer-product applications of these 

power converters, as well as the product classes for analysis and technologies for energy 

efficiency improvement. Chapter 4 describes the screening analysis, which eliminates for 

technical or economic reasons technology options that DOE will not consider in the 

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EERE-2008-BT-STD-0005 COMMENT 03
rulemaking. Chapter 5 describes the engineering analysis, which involved the selection of 

representative units for analysis and the calculation of the costs associated with 

increasing the efficiency of these units. 

Chapters 6 and 7 describe approaches DOE used to determine the impacts of the 

cost-efficiency relationship developed in chapter 5 on end users of products powered by 

BCs and EPSs. Chapter 8 is an analysis of LCC and payback period, while chapter 9 

describes methods for deriving base and standards case shipment forecasts. Chapter 10 

describes a national impact analysis, which includes a methodology to calculate national 

energy savings and the net present value of those savings. DOE will use the methodology 

described in chapter 10 to measure the impact of Federal energy conservation standards 

by (1) comparing projected U.S. energy consumption with and without new energy 

conservation standards, and (2) weighing the cost savings associated with decreased 

energy consumption against the increased end-user cost of more energy efficient products 

discounted over the 30-year analysis period. 

A determination analysis is typically less rigorous than an energy conservation 

standards rulemaking, which DOE is initiating with the publication of its framework 

document. The analyses above focused on finding just one candidate standard level the 

Secretary could use to decide whether to proceed with setting energy conservation 

standards. An energy conservation standards rulemaking considers several standards 

levels. Additionally, the analyses at each standard level are more detailed in a standards 

rulemaking compared with the determination, which evaluates average or typical cases 

and does not include sensitivity or subgroup analyses. Nonetheless, many of the inputs 

and methods used for the determination can be applied to the standards rulemaking, and 

the Department welcomes stakeholder comment on all aspects of the determination 

analysis presented in this report. 

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CHAPTER 2. MARKET ASSESSMENT 

2.1 Introduction.............................................................................................. 2-2 

2.2 The Importance of Applications .............................................................. 2-2 

2.2.1 Market Trends.......................................................................................... 2-2 

2.2.2 Consumer Products: Impact of Design on the Market for Battery Chargers 

and External Power Supplies................................................................... 2-3 

2.3 Applications That Use Battery Chargers and External Power Supplies..2-5 

LIST OF TABLES 

Table 2.1. Battery Charger Applications for Which DOE Has Shipment Data...............2-5 

Table 2.2. External Power Supply Applications for Which DOE Has Shipment Data ...2-6 

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EERE-2008-BT-STD-0005 COMMENT 03
2.1 Introduction 

This section of the Draft Technical Report summarizes the key points, data, and 

methods used in DOE’s work during the determination analysis to assess the current and 

future market for BCs and EPSs. 

2.2 The Importance of Applications 

To characterize the market for BCs and EPSs, DOE gathered information on the 

applications that use them. This method was chosen for two reasons. First, the demand 

for consumer electronics applications drives the demand for BCs and EPSs. Nearly all 

BCs and most EPSs are custom-designed for use with the application they power, 

therefore they are bundled with the application. Second, because BCs and EPSs are not 

stand-alone products, their usage profiles, energy consumption, and power requirements 

are all determined by the associated application. To develop reliable estimates of the realworld unit energy consumption of a BC or EPS, it is necessary to examine the 

application. 

Sales volume is the primary driver of demand for BCs and EPSs, but trends in 

consumer product design also affect demand. For example, increased demand for 

portability in the consumer electronics industry has driven demand for battery-powered 

products. This has increased demand for BCs and EPSs, which are used to charge 

batteries in consumer electronics. In terms of volume, the main consumer products that 

drive demand for BCs are digital cameras and power tools. For EPSs, the drivers are 

mobile phones, flat panel monitors, cordless phones, and notebook computers. 

2.2.1 Market Trends 

The major trends that affect the market for BCs and EPSs are related to the 

consumer products that are powered by these products. During its work on the 

determination analysis, DOE noted examples of particular importance to the BC and EPS 

markets. 

2.2.1.1 Demand for Consumer Product Applications 

Sales of consumer electronics and handheld appliances that use a BC or EPS have 

increased significantly in recent years. In the BC market, the sales drivers in terms of 

shipments are power tools and digital cameras. The rechargeable power tool market is 

growing strongly, partly due to improved batteries and chargers that offer more power 

and shorter charge times. 

For EPSs, DOE’s initial analysis shows that market drivers in terms of shipments 

are wireless phones, flat panel monitors, cordless phones, and notebook computers. 

Wireless phones account for the largest number of EPS sales. The Consumer Electronics 

Association estimated that 138.2 million wireless phones were sold in 2007.1 

Despite the recent rapid growth, EPS sales in this segment are expected to level 

off as wireless phones become ubiquitous in the United States. Notebook computer sales 

are the main driver behind shipments of high-power EPSs, and an emerging trend of 

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EERE-2008-BT-STD-0005 COMMENT 03
purchasing notebooks instead of desktops has pushed the nameplate output power of 

these EPSs upward, sometimes over 100 watts. 

2.2.1.2 Convergence 

Some applications using BCs and EPSs are in decline as their functions are 

incorporated into other applications. For example, personal digital assistants (PDAs) have 

become rare because their functions are increasingly incorporated into wireless phones. 

Sales of digital cameras are also slowing. This may be due largely to market saturation, 

but convergence is a factor as well as the cameras built into wireless phones improve in 

quality. Multi-function devices, some of which use EPSs, combine the features of a 

printer, copier, scanner, and fax machine into one product, and make the stand-alone, 

single-function products redundant. The convergence of applications could decrease 

demand for BCs and EPSs as consumers do more with fewer products. 

2.2.1.3 Emergence 

The consumer electronics market is quick to adopt new technology and 

experiment with new consumer products. As battery and charger technology advances, 

products that are now stationary may become portable in the future. Some of the products 

that DOE analyzed for its determination did not exist 10 years ago. New BC and EPS 

applications are likely to emerge during the period of analysis. 

2.2.1.4 Substitution 

Applications use a number of methods to obtain power, including internal power 

supplies, external power supplies, primary batteries, rechargeable batteries, and USB 

ports. Market forces and changing design choices may cause shifts between these 

methods. For example, a portable digital audio player can receive power from an EPS, a 

BC, or a USB port. One brand of portable audio player that has dominated this market is 

typically charged through a USB port. However, users can purchase an EPS to charge 

their player through a traditional wall outlet. Small LCD televisions may use an EPS, but 

as they grow larger, power requirements dictate that an internal power supply (IPS) is a 

better option. 

The presence of a standard may cause a shift away from BCs or EPSs toward 

other power sources. The magnitude of this effect depends on the design considerations 

(e.g., the need to dissipate heat in high-power applications), and the demands of the 

consumer (e.g., the desire for portability may exclude the use of an IPS). In its work on 

the determination, DOE assumed that a standard would cause no substitution effects. 

2.2.2 Consumer Products: Impact of Design on the Market for Battery Chargers 

and External Power Supplies 

Manufacturer product design and consumer choice both affect the size and growth 

of the BC and EPS market. In some consumer product categories, nearly all models are 

powered the same way. For example, most handheld vacuums are powered by BCs while 

most Wi-Fi access points are powered by EPSs. In other consumer product categories, the 

power conversion device can vary by manufacturer or model. For example, designers of 

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EERE-2008-BT-STD-0005 COMMENT 03
digital cameras have a variety of choices when deciding how to power their products, 

including using a mains-powered BC or EPS, a universal serial bus (USB)-powered BC, 

or Power over Ethernet. These differences in the source of power relate to the intended 

use of a product, consumer preferences, and industry norms. Designers choose BCs to 

power handheld vacuums because users desire portability. Wi-Fi access points are 

stationary, so designers choose an EPS. If the designer expects a digital camera to be 

used by professional photographers, a BC or EPS might be a good choice. If the designer 

expects the camera to be used in close conjunction with a computer, power through USB 

might be a good option. 

An increasing number of portable devices, such as portable digital music players, 

can be recharged through a connection to a USB computer port. It is also possible to 

charge a portable digital music player by using an EPS purchased separately from the 

music player, but because most consumers use a computer’s USB port to load music onto 

the device, most charging also occurs through the USB port. The market trend toward 

consumer products that are USB-powered could affect the number of products that are 

shipped with stand-alone power conversion devices considered to be BCs and/or EPSs. 

Both technical issues and consumer preferences can influence manufacturer 

design choices. Technical considerations may relate to the method the device uses to 

consume power (e.g., short bursts of high current as in a power tool or low levels of 

consumption as in a portable music player). Consumer preferences can also influence the 

design choice, such as having longer time between recharge, being able to operate the 

device from the mains power, and not having to wait for a battery to recharge. Variations 

in power system designs occur as manufacturers develop different design solutions to 

these problems. 

This variance in design affects the market. The shipments of a given type of 

consumer product in a given year do not necessarily correspond one-to-one with the 

number of BCs and/or EPSs that ship with those products. Technical issues and consumer 

preferences will influence manufacturer design choices, and sales of BCs and/or EPSs 

could decrease even as total sales of consumer electronics increase. 

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EERE-2008-BT-STD-0005 COMMENT 03
 

 

2.3 Applications That Use Battery Chargers and External Power Supplies 

Table 2.1 and Table 2.2 list the applications for which DOE has gathered 

shipment data. 

Table 2.1. Battery Charger Applications for Which DOE Has Shipment Data 

Product Application Notes/Definition 

Personal care products Includes rechargeable shavers, beard trimmers, massagers, 

toothbrushes, etc. 

Floor care products Includes rechargeable stick vacuums, handheld vacuums, robotic 

vacuums, etc. 

Kitchen products Includes rechargeable hand-held mixers, blenders, knives, etc. 

Universal battery chargers Used to charge rechargeable batteries. 

Digital cameras Digital cameras that are powered by proprietary batteries. 

Camcorders Camcorders and digital camcorders that are powered by proprietary 

batteries. 

Do-it-yourself (DIY) power tools Generally less powerful tools aimed at the occasional user; includes 

drills, saws, grinders, and others. 

Professional power tools Generally more powerful tools aimed at the professional user; includes 

drills, saws, grinders, and others. Typically use a fast-charging BC. 

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Table 2.2. External Power Supply Applications for Which DOE Has Shipment Data 

Product Application Notes/Definition 

Camcorders Portable consumer video recorders.* 

Cordless phones Phones lacking a cord between the base station and headset for use in 

the public switched telephone network, e.g., a traditional land line. 

Digital cameras Includes digital cameras that use an EPS. 

Flatbed scanners Desktop scanning devices.* 

Flat panel monitors Also known as a LCD monitor, to be used with a computer 

Ink-jet computer printers 

Only ink-jet computer printers are included in this analysis because 

laser printers, the other dominant technology type, use an internal 

power supply. 

LAN equipment Local Area Network equipment. This segment includes routers, hubs, 

and switches. 

Modems/fax modems Broadband modems used for digital subscriber lines (DSL), cable, or 

broadband over power line (BPL).* 

Notebook computers Desktop computers use an internal power supply and therefore only 

notebooks are considered for the analysis. 

Portable audio players Includes personal MP3 players, CD and mini disc players, and portable 

radios powered by EPSs. 

Portable gaming devices Portable gaming devices such as PlayStation Portable and Nokia 

Ngage.* 

Portable video players Includes portable DVD and multimedia players. 

Small LCD TVs Note: Large LCD TVs (23” screen size or greater) and plasma TVs use 

an internal power supply.. 

Telephone answering devices Stand-alone telephone answering machines and telephones with built-in 

answering machines. 

Wi-Fi access points IEEE 802.11a/b/g/n access points.* Hardware used as a connecting hub 

for a wireless network. 

Wireless telephones Also known as mobile or cellular phones. This category includes “smart 

phones” and personal digital assistants (PDAs). 

* Darnell Group. External AC-DC Power Supplies: Global Market Forecasts and Competitive 

Environment. 2nd Edition. 2005. Darnell Group: Corona, California. 

DOE identified other products that use a BC or EPS but did not include them in 

the determination analysis because complete data was unavailable. These applications are 

listed below. For these products, DOE lacks shipment data, splits between voltage or 

output power, usage information, or all of the above. 

Battery charger applications for which DOE lacks data include: 

• Electric carts 

• Electric outdoor appliances 

• Electric ride on toys 

• Golf cars 

• Mobility chairs 

• Rechargeable light devices 

• Toys 

• Uninterruptible power supplies 

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External power supply applications for which DOE lacks data include: 

• Alarm clocks 

• Amplifiers 

• Aquarium pumps/lights 

• Baby monitoring devices 

• Bluetooth headsets 

• Caller ID devices 

• Computer speakers 

• Distribution amplifiers 

• Electronic musical instruments 

• External computer drives 

• Fluorescent desk lamps 

• Guitar effects 

• Hair dryers 

• Handheld computers 

• Handheld image scanners 

• Indoor fountain pumps/lights 

• MP3 player speaker systems 

• MP3 player docking stations 

• Multifunction printing/scanning/faxing devices 

• Non-portable gaming devices 

• Set-top boxes 

• Water filters 

• Water softeners 

References 

1

 Consumer Electronics Association. U.S. Consumer Sales & Forecasts, 2004–2009. July 

2008. CEA: Arlington, VA. 

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CHAPTER 3.TECHNOLOGY ASSESSMENT 

3.1 Introduction................................................................................................................... 3-3 

3.1.1 The Role of Power Converters............................................................................. 3-3 

3.1.2 Different Modes of Operation.............................................................................. 3-4 

3.1.3 EPS Design Parameters........................................................................................ 3-5 

3.1.4 BC Design Parameters ......................................................................................... 3-5 

3.1.5 Product Classes .................................................................................................... 3-5 

3.1.6 Efficiency Metrics................................................................................................ 3-6 

3.1.7 Technology Options for Efficiency Improvement............................................... 3-6 

3.2 External Power Supply Modes of Operation ................................................................ 3-6 

3.2.1 EPS Active Mode................................................................................................. 3-6 

3.2.2 EPS No-Load Mode............................................................................................. 3-7 

3.3 Battery Charger Modes of Operation............................................................................ 3-7 

3.3.1 BC Active Mode .................................................................................................. 3-7 

3.3.2 BC Maintenance Mode ........................................................................................ 3-8 

3.3.3 BC No-Load Mode ............................................................................................. 3-8 

3.4 External Power Supply Design ..................................................................................... 3-9 

3.4.1 General Design of an External Power Supply ..................................................... 3-9 

3.4.2 AC/AC External Power Supplies......................................................................... 3-9 

3.4.3 Unregulated Line-Frequency AC/DC External Power Supplies ....................... 3-10 

3.4.4 Linear-Regulated Line-Frequency AC/DC External Power Supplies ............... 3-11 

3.4.5 Switching-Regulated Line-Frequency AC/DC External Power Supplies ......... 3-13 

3.4.6 Switched-Mode AC/DC External Power Supplies ............................................ 3-14 

3.5 BC Design................................................................................................................... 3-16 

3.6 Product Classes ........................................................................................................... 3-18 

3.6.1 EPS Product Classes .......................................................................................... 3-18 

3.6.2 BC Product Classes............................................................................................ 3-19 

3.7 Energy Efficiency Metrics .......................................................................................... 3-20 

3.7.1 Using Energy Efficiency Metrics....................................................................... 3-20 

3.7.2 Energy Efficiency Metrics for External Power Supplies................................... 3-20 

3.7.3 Energy Efficiency Metrics for Battery Chargers ............................................... 3-21 

3.8 Technology Options for Efficiency Improvement...................................................... 3-21 

3.8.1 EPS Technology Options................................................................................... 3-21 

3.8.2 BC Technology Options .................................................................................... 3-22 

3.8.3 Transformers...................................................................................................... 3-23 

3.8.4 Diode Losses and Synchronous Rectification.................................................... 3-24 

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LIST OF FIGURES 

Figure 3.1 Block diagram of power flowing through an external power supply......................... 3-3 

Figure 3.2 Block diagram of power flowing through a battery charger. ..................................... 3-4 

Figure 3.3 Example of an Efficiency Curve of an EPS in Active Mode ..................................... 3-7 

Figure 3.4 Circuit Diagram for an AC/AC External Power Supply .......................................... 3-10 

Figure 3.5 Circuit Diagram of a Line-Frequency Raw Supply.................................................. 3-10 

Figure 3.6 Block Diagram of a Linear Regulator ...................................................................... 3-11 

Figure 3.7 Simplified Circuit Diagram of a Linear Regulator................................................... 3-12 

Figure 3.8 Block Diagram of a Switching-Regulated Line-Frequency AC/DC EPS ................ 3-13 

Figure 3.9 Block Diagram of a Switched-Mode Power Supply ................................................ 3-14 

Figure 3.10 Simplified Circuit Diagram of a Flyback Switching Regulator ............................. 3-15 

Figure 3.11 Circuit Diagram of a BC......................................................................................... 3-16 

LIST OF TABLES 

Table 3.1. Product Classes Used in the EPS Draft Determination Analysis. ............................ 3-19 

Table 3.2 BC Product Classes Developed for the Draft Determination Analysis ..................... 3-20 

Table 3.3 Quality of Core Steel and Level of Magnetic Induction........................................... 3-23 

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EERE-2008-BT-STD-0005 COMMENT 03
 

3.1 Introduction 

This technology assessment examines BC and EPS technology, with a focus on the 

factors most affecting their efficiency. The assessment begins by explaining the purpose of EPSs 

and BCs, their legal definitions, and their different modes of operation. Next, it presents the 

parameters that govern power converter design and, based on those parameters, how DOE 

considered grouping them into product classes. Last, the technology assessment reviews 

efficiency metrics as well as methods for improving efficiency. This introduction briefly 

examines each of these points. In other chapters of this document, discussion begins with BCs; 

for the purposes of the technology assessment, it is more natural to examine EPSs first. 

The assessment presents DOE’s current understanding as well as previous unpublished 

work. In December 2006, DOE published a draft technology assessment in “The Current and 

Projected Future Market for Battery Chargers and External Power Supplies.”a DOE then 

continued to research BCs and EPSs in preparation for a determination analysis it intended to 

publish in August 2008. This technology assessment presents DOE’s understanding of BC and 

EPS technology as it was developed for the determination analysis until EISA suspended DOE’s 

examination in 2007. The purpose of this technology assessment is to present DOE’s 

understanding of the factors DOE reviewed in the screening analysis and then used in the 

engineering analysis to establish the relationship between cost and efficiency. 

3.1.1 The Role of Power Converters 

EPSs and BCs are power converters that support consumer products; hence, their 

operation and design is primarily governed by the consumer products they support (Figure 3.1 

and Figure 3.2). Generally, external power supplies provide power at a constant output voltage 

and are interchangeable among consumer products with similar power requirements. 

Alternatively, battery chargers deliver power while controlling the output current, the output 

voltage is determined by the battery. Battery chargers tend to be custom-designed for the 

charging and safety requirements of specific battery packs. 

Figure 3.1 Block diagram of power flowing through an external power supply. 

a

 This document is available at 

www.eere.energy.gov/buildings/appliance_standards/residential/pdfs/market_analysis.pdf. 

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Figure 3.2 Block diagram of power flowing through a battery charger. 

To specify, DOE is developing energy conservation standards for battery chargers and 

external power supplies defined by EPCA, as amended by EPACT. EPCA defines a battery 

charger as “a device that charges batteries for consumer products, including battery chargers 

embedded in other consumer products.” (42 U.S.C. 6291(32)) The definition for external power 

supply 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” (42 U.S.C. 

6291(36)(A)) but Section 301 of EISA further amended this definition by creating a subset of 

external power supplies called Class A External Power Suppliesb

. EISA defined this subset as 

those external power supplies that, in addition to meeting several other requirements common to 

all external power supplies, are “able to convert to only 1 AC or DC output voltage at a time” 

and that have “nameplate output power that is less than or equal to 250 watts.” (42 U.S.C. 

6291(36)(C)(i)) EPCA excludes from Class A an EPS if it “requires Federal Food and Drug 

Administration listing and approval as a medical device” or if it “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)) This framework document only considers battery 

chargers and Class A external power supplies. Separately, DOE is conducting a determination 

analysis for non-Class A external power supplies. 

3.1.2 Different Modes of Operation 

BC and EPS design choices are driven by the anticipated power requirements and time 

spent in their modes of operation, including active mode, maintenance mode (for BCs only), and 

no-load mode. Of these modes, active mode has the largest effect on the power converter’s size 

and efficiency because the maximum amount of power passes through in active mode. In the 

other operational modes, power converters provide less power; however, their power 

consumption is typically larger in proportion to the output power. 

b

 The full EISA definition of a Class A external power supply includes a device that "(I) is designed to convert line 

voltage AC input into lower voltage AC or DC output; (II) is able to convert to only 1 AC or DC output voltage at a 

time; (III) is sold with, or intended to be used with, a separate end-use product that constitutes the primary load; (IV) 

is contained in a separate physical enclosure from the end-use product; (V) is connected to the end-use product via a 

removable or hard-wired male/female electrical connection, cable, cord, or other wiring; and (VI) has nameplate 

output power that is less than or equal to 250 watts.” (42 U.S.C. 6291(36)(C)(i)) The EISA definition also excludes 

from Class A “ 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)(ii)) 

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Although both BCs and EPSs are power converters with similar modes of operation, there 

are important differences between them. An EPS can be in active mode for an indefinite amount 

of time while providing power to a load. Typically, EPSs spend most of their time in active 

mode. On the other hand, while in active mode, a BC refills a battery with energy. Therefore, the 

BC is in active mode only until the battery is filled. After that point, the BC is in maintenance 

mode, when the BC maintains the battery at full charge. 

These differences in operation lead to differences in design. For instance, BCs are 

designed around the charge type in active modefast or slow charging. The power requirements 

of the EPS load in active mode are the primary criteria affecting the EPS’s design. 

3.1.3 EPS Design Parameters 

EPSs are designed to take power from mains and convert it to a form useful to a 

consumer product. Thus, it is the consumer product that dictates the output power and output 

voltage of the EPS, the two design parameters with the biggest effect on EPS efficiency. The 

voltage requirements of the consumer product also define the tolerance of the EPS output voltage 

and whether it requires voltage regulation. These and other design parameters help determine 

whether the EPS is line frequency or high-frequency switched mode, and unregulated or voltage 

regulated. In turn, those design choices constrain which the technology options that the EPS can 

use and its consequent efficiency. 

3.1.4 BC Design Parameters 

BCs are designed to take power from mains and convert that power over time to energy 

stored in a battery; later, the battery delivers the energy to a consumer product. Thus, the 

consumer product determines the choice of battery, which also determines the characteristics of 

the battery charger. The most important design parameters of a BC are the voltage of the battery 

it will charge and the charge type, either fast or slow. The charge type—a measure of how 

quickly the BC refills its battery with energy—determines maximum output power. A BC 

defines the output current, while the battery controls the BC’s output voltage. Like an EPS, 

output power and battery voltage have the largest effect on BC design and efficiency. In turn, 

those design choices constrain which the technology options that the BC can use and its 

consequent efficiency. 

3.1.5 Product Classes 

The Department of Energy groups products into “product classes” for different energyefficiency standards when a product’s characteristics constrain its energy efficiency. As 

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)) For example, when compared 

with a standard device, a device with additional functionality that provides extra utility to the 

consumer would be grouped in a separate product class, if the additional functionality inherently 

limits its efficiency. DOE then conducts its analysis and considers establishing or amending 

standards to provide separate standard levels for each product class. For the determination 

analysis, DOE considered EPS product classes primarily based on output power and output 

voltage. For BCs, DOE considered charge type and battery voltage. 

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3.1.6	 Efficiency Metrics 

Any evaluation of efficiency depends heavily on the measures used to quantify it. This 

document considers conversion efficiency in active mode for EPSs and power consumption in 

other modes for both BCs and EPSs. DOE used previously adopted test procedures codified in 10 

CFR part 430 appendices Y and Z as the basis for evaluating efficiency for the determination 

analysis. 

3.1.7	 Technology Options for Efficiency Improvement 

The largest gains in efficiency in EPSs and BCs come from converting power with lower 

loss components and using more energy-efficient controls in the power converter. DOE analyzed 

the components in the power converter that consume significant power, such as transformers, or 

influence power consumption of other components, such as integrated circuits. By identifying 

sources of power loss and possible methods for improvement, DOE developed technology 

options that would allow a manufacturer to design a power converter with similar design 

characteristics but improved efficiency. 

3.2	 External Power Supply Modes of Operation 

3.2.1	 EPS Active Mode 

When the external power supply takes power from mains and converts it to a form usable 

by the consumer product or load it is considered to be in “active mode.” 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 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: 

Pout Pout η EPS = =	 Eq. 3.1 P P In out EPS + P _ consumption 

where ηEPS is the EPS efficiency, 

PEPS_consumptiont is the power consumed by the external power supply itself, 

Pin is the power from mains into the external power supply, and 

Pout is the power out of the external power supply to the consumer product. 

EPS efficiency varies with the amount of output power as shown in Figure 3.3. Typically, 

EPS are inefficient at low load (0 percent to 20 percent of maximum rated output power of the 

EPS) when the consumer product demands little power. However, EPS are more efficient at 

larger loads (between 20 and 100 percent of maximum rated output power) as when the 

consumer product is fully functional and demanding more power. 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 losses increase slightly, but have 

less of an effect on EPS efficiency. The EPS test procedure evaluates active mode conversion 

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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 3.3 

shows an example of a typical efficiency curve for an EPS in active mode. 

Figure 3.3 Example of an Efficiency Curve of an EPS in Active Mode 

3.2.2 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 1 watt) in no-load mode for Class A EPSs. 

3.3 Battery Charger Modes of Operation 

3.3.1 BC Active Mode 

DOE codified the definition of active mode for battery chargers in the test procedure final 

rule published in December 2006 (10 CFR part 430 subpart B appendix Y): “Active mode is the 

condition in which the battery is receiving the main charge, equalizing cells, and performing 

other onetime or limited-time functions necessary for bringing the battery to the fully charged 

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state.” For the determination analysis, DOE studied BC active mode for its effect on BC design 

and performance. However, DOE used the non-active energy ratio to evaluate efficiency, which 

does not include active mode. 

The output current of a BC in active mode is most critical at two points: when the battery 

is fully charged and when the battery is empty. When the battery is fully charged, the BC may 

need to immediately stop sending current to the battery, as in the case of lithium-based batteries. 

When a battery is empty of charge its voltage becomes very low. In that state, the BC needs to 

limit its output current because it could damage the battery and pose a safety hazard from heat 

generation. Therefore, the BC must limit the charging current until the battery voltage increases. 

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. 

3.3.2 BC Maintenance Mode 

DOE codified the definition of maintenance mode for battery chargers in the test 

procedure final rule published in December 2006 (10 CFR part 430 subpart B appendix Y): 

“Battery maintenance mode or maintenance mode is the mode of operation when the battery 

charger is connected to the main electricity supply and the battery is fully charged, but is still 

connected to the charger.” 

Once the battery reaches a fully charged state, the BC and battery are considered to be in 

maintenance mode. In this mode, the BC controls the output current to prevent the battery from 

being damaged due to excess heat generation or unwanted electro-chemical reactions. 

Specifically, the battery has different requirements depending on its chemistry. Lithium-ion (LiIon) batteries do not significantly self-discharge but do pose a serious safety hazard if 

overcharged. Consequently, Li-Ion BCs stop charging once the battery is full and require no 

maintenance current. Conversely, nickel-based batteries, such as nickel-cadmium (NiCd) and 

nickel-metal-hydride (NiMH), significantly self-discharge but are tolerant of overcharging. 

Hence, their BCs continue to provide maintenance current to keep the battery fully charged. 

Efficiency can be improved by reducing the charge current to the minimum. For BCs that do not 

provide charge current in maintenance mode, efficiency can be improved by turning off circuits 

that are not in use. 

3.3.3 BC No-Load Mode 

For the determination analysis, DOE used the definition of no-load mode codified in 10 

CFR part 430 subpart B appendix Y: “Standby mode or no-load mode means the mode of 

operation when the battery charger is connected to the main electricity supply and the battery is 

not connected to the charger.” 

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Similar to the EPS that is disconnected from the load, a BC in no-load mode does not 

deliver power to a battery. Improved efficiency in these modes stems from reducing BC power 

consumption. Many of the technology options for reducing no-load mode power consumption in 

EPSs are also valid for BCs. Some BCs also use a cradle to hold the battery during charging, 

which offers an additional energy saving technology. A BC could have a switch in the cradle that 

senses the battery’s presence and electrically disconnects the BC from mains when the battery is 

removed. 

3.4 External Power Supply Design 

3.4.1 General Design of an External Power Supply 

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 

voltage regulation to minimize voltage fluctuations caused by load or power source variations. 

Other applications that can tolerate some voltage fluctuation may use simpler EPSs that do not 

regulate the output voltage. Also, EPSs might have other specifications, such as total harmonic 

distortion or power factor. 

Of all these specifications, output power and output voltage have the largest impact on 

EPS efficiency, because together they determine the output current, which directly affects 

conduction losses and associated power dissipation in the EPS. 

Line-frequency EPSs have that name 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 linefrequency 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 high-frequency AC current 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 the AC current 

passing through the transformer is at high frequency, the transformer is smaller, resulting in 

lower weight, material costs, and losses in the transformer, all of which decrease with 

transformer volume. 

3.4.2 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 at a lower voltage 

through magnetic induction in the core. The size of the wires and core depend on the output 

power of the transformer. The output 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 

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consumer product from the 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 3.4 Circuit Diagram for an AC/AC External Power Supply 

3.4.3 Unregulated Line-Frequency AC/DC External Power Supplies 

An unregulated line-frequency EPS is referred to as a “raw supply,” which has three 

distinct stages (Figure 3.5): 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. 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 in that it is 

more than 10% of losses, if the rectifier is a bridge with two diodes. 

Figure 3.5 Circuit Diagram of a Line-Frequency Raw Supply 

The raw supply is directly responsive to the load: A change in the 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 device before the load. 

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3.4.4 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 is a concern, such as when an EPS is used with a mobile 

phone. 

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 the power-dissipating element to keep the output voltage 

fixed. 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 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 3.6). 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. 

Raw Supply 

Stage 

Mains 

Power Pass Device 

Sensor 

Linear Regulator 

Stage 

Figure 3.6 Block Diagram of a Linear Regulator 

VOut 

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Figure 3.7 shows a circuit diagram of a “low-dropout” linear regulator, one of the more 

common types of linear regulators. To determine the voltage drop across the pass device, 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 stable output voltage, which is what the load receives as the output voltage of the EPS. 

Figure 3.7 Simplified Circuit Diagram of a Linear Regulator 

The efficiency of the linear regulator, ηLinReg, is: 

P V I LinReg _ out LinReg _ out LinReg _ out η LinReg	 = = Eq. 3.2 P V I LinReg _ in LinReg _ in LinReg _ in 

where ILinReg_in is the current into the linear regulator, 

ILinReg_out is the current out of the linear regulator, 

PLinReg_in is the power into the linear regulator, 

PLinReg_out is the power out of the linear regulator, 

VLinReg_in is the voltage into the linear regulator, and 

VLinReg_out is the voltage out of the linear regulator. 

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Because the linear regulator directly attaches to the raw supply, VLinReg_in is equal to 

VRawSupp_out, the output voltage of the raw supply. 

Because the input current flows directly to the output through the pass device, with other 

currents being negligible, I LinReg _ out ≈ I LinReg _ in . Therefore, the efficiency of the linear regulator 

alone is approximately: 

VLinReg _ out η LinReg ≈ Eq. 3.3 VLinReg _ in 

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 raw supply, ηRawSup, also varies with load, 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: 

η Lin _ EPS =η RawSupp *η LinReg Eq. 3.4 

3.4.5 Switching-Regulated Line-Frequency AC/DC External Power Supplies 

An alternate to a linear regulator is a switching regulator that can also follow the raw 

supply (Figure 3.8). Switching regulators tend to be much more efficient than linear regulators 

because they do not dissipate excess power. Rather, to regulate output they take power as 

necessary to maintain constant output voltage. Due to their higher costs, these switching 

regulators tend not to be as common as linear regulators, since it is typically more cost-effective 

to use a switched-mode power supply design. 

Raw Supply 

Stage 

Mains 

Power Chopper 

Control 

VOut 

Switching Regulator Stage 

Energy 

Transfer 

Feedback 

Isolation 

Figure 3.8 Block Diagram of a Switching-Regulated Line-Frequency AC/DC EPS 

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3.4.6 Switched-Mode AC/DC External Power Supplies 

A switched-mode power supply 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 

3.9). 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 a feedback isolation stage to the controller, which tracks the output 

voltage and adjusts the chopper to make the desired voltage. 

Figure 3.9 Block Diagram of a Switched-Mode Power Supply 

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 (IC), 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 reducing 

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 usually consists of an integrated circuit controller and discrete 

components. The circuit diagram in Figure 3.10 depicts a “flyback” switching regulator, the most 

common type for EPSs used with consumer electronics; 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; the duty cycle of the transistor determines how much 

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energy is transferred through the energy transfer stage. 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. 

AC/DC Conversion 

PWM Optocoupler 

Chopper 

Control Isolation 

Energy Transfer 

+

VOut

-

+ 

VMains

-

Figure 3.10 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 3.10 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 feedback 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 for 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 

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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 at low-load or when there is no load attached, because 

the EPS will only take from the mains the small amount of power it needs to keep itself running. 

As an alternative to 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, by not having an IC, the EPS may consume less overhead 

power, but offers less functionality, such as cycle-skipping at low load, which can limit EPS 

efficiency. 

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. 

3.5 BC Design 

BCs are power converters that support consumer products and their associated batteries. 

The circuit model for the battery is a device with certain electro-chemical characteristics, as 

shown in Figure 3.11. 

Figure 3.11 Circuit Diagram of a BC 

Technology options for improving BC efficiency depend on whether the BC is a slow 

charger or a fast charger. The distinction is based on the charge rate (also referred to as C-rate), 

often defined as the average charging current into the battery, divided by the nominal battery 

charge capacity. For current expressed in amperes and battery capacity expressed in amperehours, the resulting quantity is expressed in units of 1/hours or C. For example, a BC with a 

100 milliamp (mA) output current charging a 1,000 milliamp-hour (mAh) battery would result in 

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a charge rate of 0.1 C. Charging time is roughly the inverse of the charge rate, adjusted for the 

efficiency of the battery itself, which varies with chemistry. In the previous example, charging a 

battery at 0.1 C would take slightly longer than 10 hours to charge. Slow chargers are sometimes 

referred to as “continuous chargers” because they continuously charge the battery with no 

distinction between active mode and maintenance mode. Fast chargers are typically considered 

“terminating chargers” because they charge at high current during active mode, which terminates 

in maintenance mode when the battery is fully charged. 

Slow, continuous-charging BCs are more commonly found in consumer products that 

operate infrequently and spend most of their life in maintenance mode. An example is a cordless 

hand-vacuum, which spends most of its life in a charging-base awaiting use. Continuous BCs 

provide current to the battery using the same circuit regardless of battery state and usually only 

monitor the battery for safety purposes, not the state of the 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 charge-control impedance 

used in a slow charger will cause the charging current to decrease. This reduces power 

consumption and lessens battery heating due to overcharging, thereby extending battery life. 

Slow chargers are not typically used in combination with lithium-based batteries, because of the 

safety concerns associated with overcharging these batteries. 

Slow chargers are typically composed of a line-frequency transformer followed by a 

rectifier. The charger can use either a discrete resistor or the resistance or reactance of the 

transformer windings to control the battery charging current. The conversion losses in a slow 

charger are mostly the result of magnetization losses in the transformer core, resistive losses in 

the transformer windings or other charge-control element, and diode drops in the rectifier. 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 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 power due to the transformer magnetization 

losses. 

Fast-terminating BCs recharge a battery more quickly than continuous BCs because they 

provide a high-current charge while the battery can safely accept it (during active mode). For 

example, a cordless power drill with a rapid-charge BC uses a high current to quickly charge the 

battery, often in an hour. Once the battery is fully charged, the BC maintains the battery at full 

charge with a lower current. To determine when to charge at high current, terminating BCs 

monitor inputs such as battery voltage, rate of change of battery voltage, battery temperature, 

rate of change of battery temperature, charging time, and charging current. These inputs direct a 

charging regulator in the BC to adjust output current. 

Thus, a battery charger that contains monitoring, cutoff, or limiting circuitry can safely 

charge lithium-based batteries or fast-charge nickel-based batteries. DOE considers BCs with 

charge rates greater than 0.2 C (typically between 0.6 C and 1 C) and containing safety circuits 

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that monitor the battery to be fast chargers. Because of their faster charge rate, their maximum 

rated output power is 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 often 

used with slow chargers. This design difference means that the designs are susceptible to 

different loss mechanisms. 

The two primary sources of energy consumption (and opportunities for energy savings) in 

fast-terminating BCs are transformers and battery monitoring circuits. First, there are conversion 

losses associated with switching and rectification and fixed losses due to overhead power 

consumption associated with the integrated circuit switching controller and the safety monitoring 

circuitry in a BC with a switched-mode power supply. 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 maintenance-mode power 

consumption. Even with the battery removed, the charger continues to consume significant 

power due to overhead losses. 

3.6 Product Classes 

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 this section, DOE summarizes the various product classes used by EISA 2007, 

ENERGY STAR, and the draft analysis prepared by DOE for the determination in 2007. 

3.6.1 EPS Product Classes 

Because output power and output voltage have the largest impact on achievable EPS 

efficiency, DOE considered both criteria when developing EPS product classes for its 

determination analysis. DOE reviewed EPS product classes developed by ENERGY STAR and 

those proposed by manufacturers. Version 1 of the ENERGY STAR specification only 

considered EPS output power; however, in interviews, manufacturers prompted DOE to consider 

output voltage as well. 

DOE divided the EPSs under analysis into low-, medium-, and high-power units, with the 

boundaries at 4 and 60 watts nameplate output power. Based on manufacturer input, DOE 

expected EPSs in each product class to share design characteristics that would affect the cost of 

increasing active-mode efficiency and decreasing no-load mode power consumption. For 

example, DOE expected low-power switched-mode EPSs with output power of less than 4 watts 

not to contain a controller IC, due to the high cost of an IC in relation to the total cost of the EPS. 

The high proportional cost of an IC in this case would increase the cost of improving no-load 

power consumption. 

Similarly, DOE expected EPSs with output power greater than 60 watts to be switchedmode EPSs with a two-stage circuit architecture and active power factor correction (PFC). This 

is because many EPSs are sold in both US and European markets, where there is a standard for 

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power factor. Power factor correction is necessary for meeting power-factor requirements under 

the European Union Code of Conduct, a voluntary agreement of EPS manufacturers. Due to the 

global nature of the EPS market, these requirements affect the design and cost-efficiency 

relationship of high-power EPSs in the United States. 

However, after analyzing 32 EPSs with output power less than 6 watts and 18 EPSs with 

output power greater than 50 watts, DOE was unable to find support for the above product class 

divisions (discussed further in chapter 5, Engineering Analysis). There did not appear to be clear 

thresholds at which manufacturers would begin to use controller ICs or PFC circuitry. Therefore, 

DOE did not consider EPS product classes related to these criteria, although DOE recognizes the 

important role of ICs and PFC in EPS design and anticipates further analysis of these criteria. 

In interviews held in 2007, manufacturers also suggested that DOE differentiate the EPS 

product classes by output voltage in addition to output power. When comparing EPSs with the 

same output power, EPSs with lower output voltages have higher conduction and diode-drop 

losses that pose additional challenges to achieving high efficiency. Manufacturers therefore 

suggested that DOE further subdivide its product classes by output voltage, with a division at 

12 volts, the point where the approximately 0.6-volt diode drop results in losses equal to 

5 percent of the output voltage (for a switched-mode EPS with one output rectification diode), 

and corresponding efficiency losses. Table 3.1 presents the product classes that DOE used in its 

determination analysis. Again, although there is overlap between the terms, “product class A” 

from the DOE draft determination analysis is not related to “Class A” EPSs set forth in EISA 

2007. 

Table 3.1. Product Classes Used in the EPS Draft Determination Analysis. 

Nameplate Output Nameplate Output Power 

Voltage <4 watts 4–60 watts >60 watts 

<12 volts A B C 

>12 volts D E F 

3.6.2 BC Product Classes 

There are several capacity- and performance-related features of a BC that could be used 

for classification, including the charging method it uses (continuous charging versus terminating 

charging), the charge rate, the voltage or capacity of the battery or batteries charged, and/or the 

battery chemistry. When conducting the determination analysis, DOE divided battery chargers 

into product classes based on battery voltage. This parameter, more than any other, affects the 

performance and utility of the battery charger. Battery voltage has a large impact on attainable 

battery charger efficiency as well as the opportunities for efficiency improvement. 

ENERGY STAR also created product classes for battery charging systems based on the 

voltage of the batteries or battery packs that they charge. The ENERGY STAR specification 

contains 20 product classes, divided into increments of 1.2 volts, starting at 1.2 volts to greater 

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than 24 volts. ENERGY STAR does not distinguish between battery charging systems by 

charging method, charge rate, battery capacity, or battery chemistry. 

Although manufacturers cannot easily exchange a fast charger for a slow one without 

significantly affecting consumer utility (i.e., slower charge time provides less utility), the same 

cannot be said of exchanging a slow charger for a fast one. In fact, exchanging a slow charger 

that uses a line-frequency power supply for a fast charger with a switched-mode power supply 

was a technology option manufacturers identified during interviews. 

Additionally, class divisions based on battery voltage permitted DOE to analyze the 

different technological paths to energy efficiency improvement in the major categories of BCs 

for consumer products. Table 3.2 shows these product classes. 

Table 3.2 BC Product Classes Developed for the Draft Determination Analysis 

0 V through 3 V A 

>3 V through 9 V B 

>9 V through 48 V C 

3.7 Energy Efficiency Metrics 

3.7.1 Using Energy Efficiency Metrics 

An evaluation of the effectiveness of technology options for efficiency improvement and 

the tradeoffs among them depends heavily on the measures used for quantification. This section 

presents a brief discussion of the test procedures DOE used to measure the energy consumption 

of BCs and EPSs, and any issues related to the test procedures that may affect the energy 

conservation standards rulemaking. 

Within this document, the term “energy consumption” is used loosely to refer to power 

dissipation or power consumption by BCs and EPSs in one of several modes. Likewise, 

“efficiency” can mean EPS active-mode efficiency or BC energy ratio, both discussed in the 

following sections. More generally, “efficiency” can also refer to the energy consumption of a 

BC or EPS against that of comparable devices in any of their modes. 

3.7.2 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 U.S. Environmental Protection 

Agency’s (EPA) ENERGY STAR EPS test procedure, measures active-mode efficiency and noload-mode (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 

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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 (CSLs) used in setting potential energy 

conservation standards. This “matched pairs” combination affected the analysis and is discussed 

further in chapter 5, Engineering Analysis. 

3.7.3 Energy Efficiency Metrics for Battery Chargers 

On December 8, 2006, DOE adopted a test method to measure the efficiency of battery 

chargers. 71 FR at 71340. This test method, based on the 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 “nonactive 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 nonactive power dissipation in the BC – i.e., a less efficient battery charger. 

3.8 Technology Options for Efficiency Improvement 

3.8.1 EPS Technology Options 

DOE considered seven technology options for the determination analysis 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. Section 

3.8.3 elaborates on transformers further. 

•	 Switched-Mode Power Supply. Line-frequency EPSs often 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 3.4.4 and section 

3.4.5. 

•	 Low-Power Integrated Circuits. The efficiency of the EPS can be further improved 

by substituting low-power IC controllers to drive the switching transistor, 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. This increases conversion 

efficiency and decreases no-load power consumption. 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 

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increasingly significant at low output voltage. Section 3.8.4 elaborates on rectification 

further. 

•	 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 

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. 

3.8.2 BC Technology Options 

These EPS technology options can also benefit BCs. Following is a list of four 

preliminary technology options that DOE studied for the determination analysis that apply to 

BCs in particular. 

•	 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. Most fast chargers use this technology 

option, but many slow chargers do not. 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 overcharge. 

•	 Elimination of No-Load 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. 

•	 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 

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light dimmers, can be added to the primary side of the BC power supply circuitry to 

limit input current in lower-power modes. This technology option is particularly 

applicable to fast chargers that have high maximum output current. 

3.8.3 Transformers 

For line-frequency BCs and EPSs, the largest losses are in the transformer, particularly at 

light loads. The most effective means to reduce transformer power loss at light loads is to select a 

transformer with higher quality core material and a lower level of magnetic induction. At line 

frequency, the transformer core material typically is thinly laminated steel alloyed with silicon. 

The amount of silicon affects the core power loss and the cost of the transformer. Core 

performance is enhanced by magnetically orienting the grain structure in the metal. The industry 

standard for common non-oriented grain-structure core material ratings range from M19 to M45, 

with the lower number having fewer electrical losses. M6 core steel is used in an energy efficient 

EPS transformer because it is a high-quality grain-oriented core steel that has very low electrical 

losses. 

The second important factor contributing to core loss is the level of magnetic induction. 

Core losses are measured in watts per pound (W/lb), and induction is given in kilogauss (kG). 

Induction levels in these devices typically range between 10 kG and 15 kG. Reducing the 

induction level will reduce the core losses, but increase the winding losses. Reducing the 

induction requires more wire turns and therefore a larger core for a given power rating. The 

trade-off of these improvements is the increased size and weight of the transformer, and 

ultimately the EPS. Table 3.3 shows the effects of material type and induction on core loss. 

Power loss in the transformer core can be reduced by an order of magnitude by increasing the 

quality of the core steel and reducing the level of magnetic induction: 0.28 W/lb versus 3.1 W/lb. 

Table 3.3 Quality of Core Steel and Level of Magnetic Induction 

Steel 

Core Losses at Various Levels of Magnetic Induction 

10 kG 12 kG 15 kG 

M6 0.28 W/lb 0.40 W/lb 0.60 W/lb 

M19 0.85 W/lb 1.2 W/lb 2.0 W/lb 

M45 1.4 W/lb 1.9 W/lb 3.1 W/lb 

Additionally, some primary transformer windings have high resistance to prevent failure 

in the case of overload conditions. Using a separate fuse or thermal cutout to prevent failure 

would allow the transformer to have a lower winding resistance, thus reducing electrical losses. 

A large potential source of energy loss in a high-frequency EPS is the flyback choke, 

similar to the transformer in line-frequency EPSs. Methods of improving the energy efficiency of 

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chokes are similar to those for improving transformers, that is, improving the core material and 

increasing the amount of copper to reduce copper losses. 

Particularly, for EPSs with output power greater than 10 W, a switched-mode power 

supply is generally a more efficient alternative to a line-frequency. At lower wattages, however, 

neither regulation technology has a clear efficiency advantage. This is partly because the 

switching regulator circuit components themselves consume some energy, regardless of the 

output power of the device. At lower wattages, this fixed energy consumption is a more 

significant proportion of total EPS energy consumption. 

3.8.4 Diode Losses and Synchronous Rectification 

Diodes are another source of loss for DC line-frequency EPSs. These losses increase as 

the output voltage decreases, and become particularly significant below 12 V. The power 

consumed by a diode is the product of the current flowing through the diode multiplied by the 

voltage drop across it. When a line-frequency EPS is designed for low-output voltage, that drop 

becomes a significant portion of the overall losses in the EPS. Using Schottky diodesc

 reduces 

the voltage drop across the diodes, thus improving efficiency. Conventional diodes have a 

voltage drop of about 0.6 V, which can be reduced to about 0.3 V to 0.4 V by using Schottky 

diodes. 

Synchronous rectification offers even lower losses by replacing diodes with transistors. In 

this situation, the transistor mimics the rectification effect of the diode. However, the loss across 

the source-to-drain resistance of the transistor is much lower than that of a diode. Typically, 

synchronous rectification replaces diodes on the secondary side of the transformer in switchedmode EPSs because that is where it offers the most energy savings. 

c

 A Schottky diode is a metal-semiconductor diode with a smaller voltage drop than a conventional diode, therefore 

consumes less power. 

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CHAPTER 4. SCREENING ANALYSIS 

4.1 Introduction.................................................................................................................. 4-2 

4.2 Technology Options for Improving BC and EPS Efficiency....................................... 4-2 

4.3 Design Options Not Screened Out of the Analysis...................................................... 4-3 

4.3.1 Improved Transformer Cores............................................................................... 4-3 

4.3.2 Improved Transformer Windings ........................................................................4-3 

4.3.3 Switched-Mode Power Supply Architecture ....................................................... 4-4 

4.3.4 Low-Power Integrated Circuit Controllers .......................................................... 4-4 

4.3.5 Schottky Rectifier Diodes....................................................................................4-4 

4.3.6 Synchronous Rectification...................................................................................4-5 

4.3.7 Low-Loss Transistors...........................................................................................4-5 

4.3.8 Resonant Switching ............................................................................................. 4-5 

4.3.9 Resonant Snubbers............................................................................................... 4-6 

4.3.10 Termination.......................................................................................................... 4-6
 

4.3.11 Elimination or Limitation of Maintenance Current ............................................. 4-6 

4.3.12 Elimination of No-Battery Current ...................................................................... 4-7 

4.3.13 Phase Control to Limit Input Power .................................................................... 4-7 

4.4 Conclusion ................................................................................................................... 4-7 

LIST OF TABLES 

Table 4.1. Technology Options for Improving BC and EPS Efficiency ..................................... 4-3 

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4.1 Introduction 

The purpose of the screening analysis is to identify and eliminate any technology options 

that DOE will not consider in the rulemaking for BCs and EPSs. For the determination analysis, 

DOE began with the technology options presented in the technology assessment (chapter 3), 

which were developed following consultations with industry, technical experts, and other 

interested parties, and by reviewing the available literature. Before considering the technology 

options in the engineering analysis (chapter 5), DOE reviewed each technology option or best 

available technology in light of the following four criteria, as adapted from sections 4(a)(4) and 

5(b) of the Process Rule1

: 

1. Technological feasibility. DOE will not consider technologies that are not incorporated in 

commercially available products or working prototypes. 

2. Practicability to manufacture, install, and service. If DOE determines that mass 

production of a technology in commercial products and reliable installation and servicing 

of the technology could not be achieved on the scale necessary to serve the relevant 

market by the time of the effective date of the standard, it will not consider that 

technology further. 

3. Adverse impacts on product or equipment utility or availability. If DOE determines that a 

technology has significant adverse impact on the utility of the product to significant 

subgroups of consumers, or results in the unavailability of any covered product type with 

performance characteristics (including reliability), features, size, capacities, and volumes 

that are substantially the same as products generally available in the United States at the 

time of the rulemaking, it will not consider that 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 that technology 

further. 

This chapter discusses all the technology options DOE considered for improving the 

energy efficiency of BCs and EPSs, and describes how DOE applied the screening criteria. 

Technology options that were not screened out through this process were termed “design 

options” and became instrumental to the development of cost-efficiency curves in the 

engineering analysis. 

4.2 Technology Options for Improving BC and EPS Efficiency 

The technology options for improving BC and EPS efficiency, previously identified in 

chapter 3, are listed again in Table 4.1 for convenience. As noted in chapter 3, BCs contain a 

power supply, either external or internal, for converting high-voltage AC wall current to lowvoltage DC, necessary for charging the battery. Therefore, because many of the technology 

options are general improvements to power supply efficiency, they are applicable to both BCs 

and EPSs. 

1 10 CFR part 430, subpart C, appendix A. 

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Table 4.1. Technology Options for Improving BC and EPS Efficiency 

Technology Option Area of Improvement Applicability (BC or EPS) 

Improved Transformer Cores 

Improved Transformer 

Windings 

Switched-Mode Power Supply 

Architecture 

Low-Power Integrated 

Circuit (IC) Controllers 

Schottky Diode Rectifiers 

Synchronous Rectification 

Low-Loss Transistors 

Resonant Switching 

Resonant Snubbers 

Charge Termination 

Elimination or Limitation of 

Maintenance Current 

Elimination of No-Battery 

Current 

Primary-Side Phase Control 

Magnetization Losses 

Conduction Losses 

General 

General 

Rectification Losses 

Rectification Losses 

Switching Losses 

Switching Losses 

Switching Losses 

Non-Active BC Losses 

Non-Active BC Losses 

Non-Active BC Losses 

Non-Active BC Losses 

BC, EPS 

BC, EPS 

BC, EPS 

BC, EPS 

BC, EPS 

BC, EPS 

BC, EPS 

BC, EPS 

BC, EPS 

BC 

BC 

BC 

BC 

4.3 Design Options Not Screened Out of the Analysis 

In the subsections that follow, these technology options are evaluated as design options 

based on the four screening analysis criteria. 

4.3.1 Improved Transformer Cores 

In line-frequency power supplies, whether for BC or EPS applications, the transformer 

has the largest effect on efficiency. Even in switched-mode power supplies, gains in efficiency 

can be made by improving the core of the high-frequency choke, a component with a similar 

structure and function as the transformer. In either case, DOE found that efficiency can be 

improved by replacing cores with ones made of lower-loss material. 

DOE did not screen out improved cores as a means of improving efficiency. Because this 

design technique is in commercial use today, DOE considered this technology option to be both 

technologically feasible and practicable to manufacture, install, and service. DOE considered but 

is not aware of any adverse impacts on consumer utility or reliability associated with improved 

cores. Similarly, DOE is not aware of any adverse impacts on health or safety that might be 

associated with improved cores. 

4.3.2 Improved Transformer Windings 

Besides the core, a transformer or choke also consists of windings. These are typically 

composed of long lengths of thin copper wire, which contribute significant resistance. As 

explained in chapter 3, increasing the thickness of the wire is one method of decreasing the 

losses due to winding resistance. 

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DOE did not screen out improved windings as a means of improving efficiency. 

Designers routinely vary winding resistance to meet specifications. Because this design 

technique is in commercial use today, DOE considered this technology option to be both 

technologically feasible and practicable to manufacture, install, and service. DOE considered but 

is not aware of any adverse impacts on consumer utility or reliability associated with improved 

windings. Similarly, DOE is not aware of any adverse impacts on health or safety that might be 

associated with improved windings. 

4.3.3 Switched-Mode Power Supply Architecture 

Despite improvements that can be made to line-frequency designs, the topology is 

fundamentally limited in efficiency. By redesigning the power supply to use a switched-mode 

circuit architecture, a designer can limit losses associated with both the transformer and the 

linear regulator that is typically used in line-frequency designs. 

DOE did not screen out switched-mode architectures as a means of improving efficiency. 

Despite the fact that a switched-mode architecture represents a complete redesign of the power 

supply, it is becoming increasingly common even in lower-power applications, where its smaller 

size promotes mobility. Because this design technique is in commercial use today, DOE 

considered this technology option to be both technologically feasible and practicable to 

manufacture, install, and service. Although DOE received input during the determination 

analysis about some applications whose usability was affected by lower output current limits and 

lesser electromagnetic compatibility of switched-mode EPS designs, DOE does not regard these 

as insurmountable obstacles to the adoption and commercialization of this technology option. 

DOE is not aware of any adverse impacts on health or safety that might be associated with a 

change to switched-mode architecture. 

4.3.4 Low-Power Integrated Circuit Controllers 

The efficiency of the EPS can be further improved by substituting in low-power 

integrated circuit (IC) controllers, which can switch more efficiently in active mode and reduce 

power consumption in no-load mode. 

DOE did not screen out low-power IC controllers as a means of improving efficiency. IC 

manufacturers offer numerous low-power controllers for use in BCs and EPSs, and many designs 

already incorporate these components. Because it is in commercial use today, DOE considered 

this technology option to be both technologically feasible and practicable to manufacture, install, 

and service. DOE considered but is not aware of any adverse impacts on consumer utility or 

reliability associated with low-power controllers. Similarly, DOE is not aware of any adverse 

impacts on health or safety that might be associated with low-power IC controllers. 

4.3.5 Schottky Rectifier Diodes 

Except for limited applications that require an AC output, both line-frequency and 

switched-mode power supplies use rectifier diodes to convert the AC output of the transformer to 

DC, usable by the application. Schottky diodes, which have lower voltage drops, can replace 

standard p-n junction diodes to reduce rectification losses, which become increasingly significant 

at lower output voltages. 

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EERE-2008-BT-STD-0005 COMMENT 03
DOE did not screen out Schottky diodes as a means of improving efficiency. These 

devices are commonly used in BCs and EPSs with lower output voltages. Because it is in 

commercial use today, DOE considered this technology option to be both technologically 

feasible and practicable to manufacture, install, and service. DOE considered but is not aware of 

any adverse impacts on consumer utility or reliability associated with Schottky diodes. Similarly, 

DOE is not aware of any adverse impacts on health or safety that might be associated with 

Schottky diodes. 

4.3.6 Synchronous Rectification. 

Synchronous rectification, only used in switched-mode power supplies, further reduces 

losses by substituting transistors for the rectifying diodes. The voltage drop across a transistor is 

much lower than that across even a Schottky diode, leading to lower losses in the output rectifier. 

DOE did not screen out synchronous rectification as a means of improving efficiency. 

Despite its high cost and complexity of implementation, synchronous rectification is available 

today and is used in EPSs when the application merits it. Because it is in commercial use today, 

DOE considered this technology option to be both technologically feasible and practicable to 

manufacture, install, and service. DOE considered but is not aware of any adverse impacts on 

consumer utility or reliability associated with synchronous rectification. Similarly, DOE is not 

aware of any adverse impacts on health or safety that might be associated with synchronous 

rectification. 

4.3.7 Low-Loss Transistors 

The transistor in a switched-mode power supply dissipates energy because of 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. 

DOE did not screen out low-loss transistors as a means of improving efficiency. 

Switching transistors continually improve, providing options for increasing efficiency with little 

added design complexity. Because it is in commercial use today, DOE considered this 

technology option to be both technologically feasible and practicable to manufacture, install, and 

service. DOE considered but is not aware of any adverse impacts on consumer utility or 

reliability associated with low-loss transistors. Similarly, DOE is not aware of any adverse 

impacts on health or safety that might be associated with low-loss transistors. 

4.3.8 Resonant Switching 

In addition to reducing the RDS_ON of the transistor, power consumption can be lowered 

further by the IC controller decreasing switching transients through zero-voltage or zero-current 

switching, which greatly limits losses due to switching transients in the transistor. 

DOE did not screen out resonant switching as a means of improving efficiency. Resonant 

switching does involve some additional circuit complexity, but is a common method of 

increasing efficiency. Because it is in commercial use today, DOE considered this technology 

option to be both technologically feasible and practicable to manufacture, install, and service. 

DOE considered but is not aware of any adverse impacts on consumer utility or reliability 

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EERE-2008-BT-STD-0005 COMMENT 03
associated with resonant switching. Similarly, DOE is not aware of any adverse impacts on 

health or safety that might be associated with resonant switching. 

4.3.9 Resonant Snubbers 

In switched-mode EPSs, a snubber protects the switching transistor from the high voltage 

spike that occurs after the transistor turns off. Whereas a conventional snubber dissipates the 

energy in the voltage spike as heat, a resonant or lossless snubber recycles that energy, leading to 

lower losses. 

DOE did not screen out resonant snubbers as a means of improving efficiency. As with 

resonant switching, resonant snubbers involve some additional circuit complexity, but are a 

common method of increasing efficiency. Because it is in commercial use today, DOE 

considered this technology option to be both technologically feasible and practicable to 

manufacture, install, and service. DOE considered but is not aware of any adverse impacts on 

consumer utility or reliability associated with resonant snubbers. Similarly, DOE is not aware of 

any adverse impacts on health or safety that might be associated with resonant snubbers. 

4.3.10 Termination 

Substantially decreasing the charge current delivered by the BC to the battery after it has 

reached full charge, either by using a timer or sensor, can significantly decrease maintenancemode power consumption. Whereas fast chargers already universally employ this technology 

option for safety reasons, many slow chargers do not, and wider popularity could lead to 

increased energy savings. 

DOE did not screen out termination as a means of improving efficiency. While 

termination may require redesign and significant circuit cost in the case of slow chargers, it is 

already universal in fast chargers. Because it is in commercial use today, DOE considered this 

technology option to be both technologically feasible and practicable to manufacture, install, and 

service. DOE considered but is not aware of any adverse impacts on consumer utility or 

reliability associated with termination. Similarly, DOE is not aware of any adverse impacts on 

health or safety that might be associated with termination. 

4.3.11 Elimination or 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 further decrease maintenance-mode power consumption. 

DOE did not screen out elimination or limitation of maintenance current as a means of 

improving efficiency. While this technology may add some circuit complexity in the form of 

timers or sensors, DOE did not consider the added design difficulty insurmountable. Unlike 

many of the other technologies, elimination or limitation of maintenance current is not 

widespread today, but several manufacturers have suggested it as an option for further 

eliminating maintenance current. Because manufacturers familiar with the intricacies of BC 

design identified this technology, DOE considered it to be both technologically feasible and 

practicable to manufacture, install, and service. DOE considered but is not aware of any adverse 

impacts on consumer utility or reliability associated with limitation of maintenance-mode 

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current, and in some applications complete elimination of the current may be possible. Similarly, 

DOE is not aware of any adverse impacts on health or safety that might be associated with the 

elimination or limitation of maintenance-mode current. 

4.3.12 Elimination of No-Battery Current 

A mechanical AC line switch inside the charger "cup," or charging base, automatically 

disconnects the BC from the mains supply when the battery is removed from the charger, thereby 

eliminating no-battery power consumption without incurring energy consumption penalties in 

any of the other modes. 

DOE did not screen out elimination of no-battery current as a means of improving 

efficiency. Although AC line switches are not in widespread use today, the fundamentals of this 

technology option are simple and DOE considered it to be both technologically feasible and 

practicable to manufacture, install, and service. DOE considered, but was not aware of any 

adverse impacts on consumer utility or reliability associated with elimination of no-battery 

current. Similarly, DOE was not aware of any adverse impacts on health or safety that might be 

associated with elimination of no-battery current. 

4.3.13 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. 

DOE did not screen out phase control as a means of improving efficiency. Similar to AC 

line switches, this technology option is not in widespread use today, but it is well understood and 

common in other applications outside of BCs and EPSs. DOE therefore considered it to be both 

technologically feasible and practicable to manufacture, install, and service. DOE considered but 

is not aware of any adverse impacts on consumer utility or reliability associated with elimination 

of no-battery current. Similarly, DOE is not aware of any adverse impacts on health or safety that 

might be associated with elimination of no-battery current. 

4.4 Conclusion 

Because all of the technology options summarized in Table 4.1 met the four screening 

criteria, none were eliminated in the screening analysis. DOE therefore evaluated all of the 

technology options as design options in the engineering analysis described in chapter 5. 

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CHAPTER 5. ENGINEERING ANALYSIS 

5.1 Introduction................................................................................................................... 5-4 

5.2 Selection of Representative Product Classes and Representative Units....................... 5-5 

5.2.1 BC Representative Product Classes and Representative Units............................ 5-5 

5.2.2 EPS Representative Product Classes ................................................................... 5-6 

5.2.3 EPS Representative Units .................................................................................... 5-7 

5.3 Selection of Candidate Standard Levels ....................................................................... 5-8 

5.3.1 BC Candidate Standard Levels ............................................................................ 5-9 

5.3.2 EPS Candidate Standard Levels......................................................................... 5-10 

5.4 Manufacturer Interviews............................................................................................. 5-12 

5.4.1 BC Manufacturer Interview Overview .............................................................. 5-13 

5.4.2 BC Manufacturer Interview Responses and Preferred Design Options............. 5-14 

5.4.3 BC Manufacturer Interview Data Analysis........................................................ 5-16 

5.4.4 Supplements to BC Manufacturer Interview Data............................................. 5-17 

5.4.5 Scaling of BC Manufacturer Interview Data to Representative Units............... 5-19 

5.4.6 BC Manufacturer Markups ................................................................................ 5-21 

5.4.7 EPS Manufacturer Interview Overview............................................................. 5-22 

5.4.8 EPS Manufacturer Interview Responses and Preferred Design Options........... 5-22 

5.4.9 Scaling of EPS Manufacturer Interview Data to Representative Unit Volume. 5-24 

5.4.10 Scaling of EPS Manufacturer Interview Data to Representative Unit Power ... 5-25 

5.4.11 Scaling of EPS Manufacturer Interview Data to Representative Unit Voltage. 5-28 

5.4.12 EPS Manufacturer Markups............................................................................... 5-29 

5.5 Efficiency Testing and Teardowns ............................................................................. 5-30 

5.5.1 BC Testing ......................................................................................................... 5-30 

5.5.2 BC Teardowns ................................................................................................... 5-32 

5.5.3 EPS Testing........................................................................................................ 5-34 

5.5.4 EPS Teardown Methodology............................................................................. 5-37 

5.5.5 EPS Teardown Results....................................................................................... 5-37 

5.6 Conclusion .................................................................................................................. 5-43 

APPENDIX 5.A Battery Charger Cost-Efficiency Estimation Survey .............................. 5-44 

APPENDIX 5.B EPS Cost-Efficiency Estimation Survey ................................................. 5-51 

APPENDIX 5.C Example BC Teardown Analysis Report ................................................ 5-57 

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LIST OF FIGURES 

Figure 5.1 Comparison of Active Mode Efficiency and No-Load Power; Arrows Point in 

Direction of Increased Efficiency........................................................................... 5-11 

Figure 5.2 Relationship Between BC Wall-Adapter No-Load Power and System No-Battery and 

Maintenance Power ................................................................................................ 5-19 

Figure 5.3 Full Cost of Product: Breakdown of Production and Non-Production Costs........... 5-21 

Figure 5.5 Markup Chain Diagram for Battery Chargers.......................................................... 5-22 

Figure 5.6. Schematic Illustration of the Distribution of Efficiency Versus Maximum Rated 

Output Power; the ENERGY STAR Level Is Shown as a Pink Line, while the Blue 

Background Indicates Where Most of the Units Lie .............................................. 5-26 

Figure 5.8. ENERGY STAR Level and Calculated Best-in-Market and Worst-in-Market Curves5-27 

Figure 5.11 DOE Battery Charger Test Data Superimposed over CEC Data gathered by Ecos 

Figure 5.7. Schematic Illustration of Scaling EPS Efficiency with Output Power.................... 5-27 

Figure 5.9 Relationship Between Output Voltage and Efficiency............................................. 5-29 

Figure 5.10 DOE Battery Charger Test Results by Consumer Product Application................. 5-31 

Consulting............................................................................................................... 5-32 

Figure 5.12 Low-Volume Cost Versus Efficiency for Tested and Torn-Down Battery Chargers5-33 

Figure 5.13 Illustration of Units in Product Class A Selected for Phase 2 Testing and Teardowns5-36 

Figure 5.14 Illustration of Units in Product Class B Selected for Phase 2 Testing and Teardowns5-36 

Figure 5.15 Illustration of Units in Product Class F Selected for Phase 2 Testing and Teardowns5-37 

Figure 5.19 Average Efficiency and No-Load Power Consumption of 5-Watt EPSs with BOM 

Figure 5.16 BOM Cost versus Average Efficiency of 5-Watt Units ......................................... 5-38 

Figure 5.17 BOM Cost vs. No-Load Power of 5-Watt Units .................................................... 5-39 

Figure 5.18 BOM Cost and Efficiency of 5-Watt EPS Units .................................................... 5-40 

Costs; Increasingly Stringent CSLs Are Represented by Darker Shades of Blue.. 5-40 

Figure 5.20 BOM Cost vs. Average Efficiency of 60-Watt Units............................................. 5-41 

Figure 5.21 BOM Cost versus No-Load Power of 60-Watt Units............................................. 5-42 

Figure 5.22 BOM Cost and Efficiency of 60-Watt EPS Units .................................................. 5-42 

Figure 5.23 Average Efficiency and No-Load Power Consumption of 60-Watt EPSs with BOM 

Costs; the Increasing CSLs Are Represented by Darker Shades of Blue............... 5-43 

LIST OF TABLES 

Table 5.1 Representative Unit Characteristics for Battery Chargers........................................... 5-5 

Table 5.2 Additional Characteristics of BC Representative Units .............................................. 5-6 

Table 5.3 Representative Product Classes Used in the EPS Determination Analysis................. 5-6 

Table 5.4 External Power Supply Representative Unit Characteristics....................................... 5-7 

Table 5.5 Additional Characteristics of EPS Representative Units............................................. 5-8 

Table 5.6 BC Candidate Standard Levels by Representative Unit ............................................ 5-10 

Table 5.7 EPS Candidate Standard Levels by Representative Unit........................................... 5-12 

Table 5.8 Maintenance and No-Battery Mode Power Consumption Levels Used in Manufacturer 

Interviews ............................................................................................................... 5-14 

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Table 5.9 Product Class-Average BC Wall Adapter No-Load Power Consumption ................ 5-18 

Table 5.10 Average Calculated BC Performance Used to Supplement Manufacturer Data ..... 5-19 

Table 5.11 Typical Markups and Add-Ons for Each BC Representative Unit.......................... 5-22 

Table 5.12 Unit Volumes and Volume Discount Rates for Each EPS Representative Unit ..... 5-24 

Table 5.13 Volume Prices Used to Calculate Average per-Decade Discount Rate................... 5-25 

Table 5.14 Manufacturer Markups Used in the EPS Engineering Analysis.............................. 5-30 

Table 5.15 Phase One Units Purchased and Their Characteristics ............................................ 5-35 

Table 5.16 Phase One Units Torn Down ................................................................................... 5-38 

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5.1 Introduction 

The purpose of the engineering analysis is to determine the relationship between a power 

converter’s efficiency and its manufacturer selling price (MSP).1 This relationship serves as the 

basis for the underlying costs and benefits to individual consumers (chapter 8, life-cycle cost 

analysis) and the nation (chapter 10, national impact analysis). The output of the engineering 

analysis provides the MSP at selected, discrete levels of efficiency for several “representative” 

BCs and EPSs. The levels are termed candidate standard levels (CSLs). This chapter details the 

development of this portion of the rescheduled determination analysis, which DOE conducted in 

2007, and includes descriptions of the analysis structure, inputs, and some draft outputs for 

stakeholder review and comment. 

Representative product classes and units allow DOE to focus on a few specific power 

converters and expand that knowledge to all units. Thus, DOE began the engineering analysis by 

identifying the representative product classes and selecting one representative unit for analysis 

from each of the representative product classes. The representative product classes, a subset of 

the product classes identified in chapter 3, contain the majority of the covered devices available 

in the market. The representative units, in turn, are idealized models of the most popular or 

typical devices within the representative product classes. Representative units are defined partly 

by specifications on output power and/or voltage. 

During the determination analysis, DOE presumed that findings relating to the 

representative unit would be applicable to all the units in the product class. Later, in the national 

impact analysis (NIA), DOE scaled the analytical findings for each representative unit to other 

units in the same representative product class, and from the representative product classes to 

other product classes that DOE did not explicitly analyze. See section 5.2 for a description of 

representative product classes and units used in the determination analysis. 

Although the efficiency of power converters in the market forms an almost continuous 

spectrum, DOE focused its analysis at several discrete CSLs (described in section 5.3). In the 

engineering analysis, DOE examined the cost of meeting each CSL for each representative unit. 

The resulting relationship, which followed a path of increasing cost with increasing efficiency, 

was termed an “engineering curve” or “cost-efficiency curve.” 

The analysis began with the baseline CSL, which models the most common, cheapest, 

least-efficient devices in a product class, and ended with the maximum technologically feasible 

(“max-tech”) CSL, which is typically the most expensive. To construct engineering curves for 

the determination analysis conducted in 2007, DOE relied on manufacturer interviews as its 

primary source of data, structuring the collection of this data around the interview guide 

presented in appendix 5.A. 

In its interviews, DOE asked manufacturers to speculate on the costs of improving each 

representative unit from the baseline CSL to the maximum technologically feasible CSL. DOE 

also asked manufacturers to describe the markups they would be likely to apply to the cost of 

1

 This is the price that a power converter manufacturer charges original equipment manufacturers, distributors, 

and/or retailers. The MSP forms the basis for the price consumers eventually pay. 

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EERE-2008-BT-STD-0005 COMMENT 03
production, resulting in a manufacturer selling price to distributors, original equipment 

manufacturers (OEMs), or retailers. For a detailed discussion of the interview process, see 

section 5.4. To validate the information provided by manufacturers, DOE performed its own 

testing and teardowns. 

In addition to obtaining information through manufacturer interviews, DOE developed a 

range of possible costs of production, beginning with component costs. DOE then applied 

markups to arrive at an MSP. The process of evaluating the cost of a BC or EPS started with 

DOE conducting efficiency tests of commercially available BCs and EPSs, followed by 

teardowns, parts counts, and preparation of bills of materials (BOMs). DOE then scaled these 

BOM costs to account for the lower prices paid by manufacturers purchasing at higher volumes. 

Following the teardowns, and in cases when manufacturers provided BOM costs rather 

than MSPs, DOE applied typical manufacturer markups to the resulting high-volume BOM cost 

to account for additional manufacturer costs not included in the BOM. The manufacturer 

markups included (1) a production markup, (2) an add-on for packaging and mechanical 

components, and (3) a non-production markup. The result of this markup chain was an MSP, 

which could be compared against the prices provided directly by manufacturers. Throughout this 

process, DOE consulted publicly available literature and datasets, which served as a third type of 

validation. For detailed discussion of testing and teardowns, see section 5.5. 

5.2 Selection of Representative Product Classes and Representative Units 

5.2.1 BC Representative Product Classes and Representative Units 

Each product class discussed in chapter 3 was represented by a unit that served as the 

focus of the analysis, except for product class C, which was represented by two units. Although 

fast chargers exist in all three BC product classes, they are particularly prevalent in high-voltage 

power-tool chargers, so DOE decided to split the analysis of the high-voltage product class C by 

charge rate. Table 5.1 shows the characteristics of the representative units. DOE chose these 

units because they represent high-volume BCs within each of the BC product classes. The 

engineering analysis that DOE performed on each of these units served as the basis for 

subsequent analyses of the impacts of potential energy conservation standards on consumers and 

the Nation. 

Table 5.1 Representative Unit Characteristics for Battery Chargers 

Product Class Battery Voltage Battery Capacity Charge Rate 

Typical 

Application 

A 1.2 V 1.2 Ah 0.1 C Shaver 

B 4.8 V 1.2 Ah 0.1 C Vacuum 

C 18 V 1.5 Ah 0.15 C DIY* tool 

C 18 V 2.4 Ah 1 C Pro tool 

* Do-it-yourself (DIY) tools are typically purchased by non-professional users. 

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EERE-2008-BT-STD-0005 COMMENT 03
The efficiency of BCs is affected by other parameters besides battery voltage, battery 

capacity, and charge rate. These other parameters include the length of the DC output cord (if 

one exists) and venting, among others. Again, to isolate the impacts of efficiency on cost, these 

parameters were fixed throughout the analysis to the values listed in Table 5.2. 

Table 5.2 Additional Characteristics of BC Representative Units 

Parameter Value 

Input Voltage 

Input Protection 

Unit Volume 

Packaging 

Cord Length 

Regulatory Compliance 

Product Lifetime 

115 volts rms, 60 Hz 

Primary current fuse 

200,000 units/year 

Sealed plastic 

6 feet 

UL, FCC 

> 2 years 

5.2.2 EPS Representative Product Classes 

Initially, DOE divided EPSs into six product classes, presented in chapter 3. These 

classes were based on output power and voltage because of the impact these design parameters 

have on the efficiency of an EPS. Following further discussion with manufacturers, DOE 

narrowed its focus within the list of the six product classes to three representative product 

classes. While the six EPS product classes were based on output power and voltage, the three 

representative product classes, presented in Table 5.3, were based solely on output power. DOE 

chose these representative product classes and criteria for division because manufacturers design 

“families” of EPSs with the same output power, but different output voltages. Therefore, for a 

given output power, low-voltage and high-voltage EPSs share the same design, often differing 

only in the choice of component values. Because of this similarity in design, there is a functional 

relationship between the efficiency achievable by units of different output voltage. Therefore, 

DOE did not perform a differential analysis of separate voltage-based representative product 

classes. 

Table 5.3 Representative Product Classes Used in the EPS Determination Analysis 

Nameplate Output Power 

< 4 watts 4–60 watts > 60 watts 

Product Class A B F 

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5.2.3 EPS Representative Units 

For each of the three representative EPS product classes described in section 5.2.2, DOE 

identified a representative unit for evaluation in the engineering analysis. A representative unit is 

an idealized EPS that shares the design specifications of popular EPS in the product class. Using 

these idealized units allows DOE to vary the active mode efficiency and no-load current while 

holding all other parameters (e.g., nameplate output power, voltage, safety requirements, etc.) 

constant. 

The representative units for each of the three representative product classes discussed 

previously are listed in Table 5.4. These units model typical EPSs that ship with high-volume 

applications, such as laptop computers or video-game consoles, in the case of the 90-watt, 19­

volt representative unit for product class F.2 

Similarly, the other EPS representative units model typical nameplate output power and 

voltage combinations for other high-volume products. DOE chose the representative unit for 

product class A to represent a typical wall adapter for a cellular telephone, the consumer product 

associated with the highest volume of EPS sales. DOE chose product class B’s representative 

unit to be characteristic of mid-power applications such as modems or wireless routers. 

Although DOE recognizes that laptop computer EPSs span a wide range of nameplate 

output powers and voltages, 90 watts is near the shipment-weighted average output power for the 

product class, while 19 volts is a common output voltage. Similarly, the nameplate output 

powers and voltages of the other representative units are also typical, with the output powers 

falling near the shipment-weighted averages for each class. 

Table 5.4 External Power Supply Representative Unit Characteristics 

Representative 

Product Class 

Output Power 

(W) 

Output Voltage 

(V) Typical Application 

A 

B 

F 

2.75 W 

18 W 

90 W 

5 V 

12 V 

19 V 

Cellular Telephone 

Modem 

Laptop Computer 

In addition to output current and voltage, manufacturers and customers specify other EPS 

parameters to ensure safe compatibility of the EPS design with the product it is meant to power. 

These other parameters, like output cord length, input protection, or transient response, can also 

have an impact on EPS efficiency and no-load power. Therefore, when conducting the 

engineering analysis, DOE fixed these parameters to eliminate certain design options, such as a 

shorter output cord, that might negatively affect the usability or interoperability of the EPS. 

2

 The associated framework document includes a discussion of the BC and EPS definitions and how they would be 

applied to a battery powered product, such as a laptop computer, that uses an external wall adapter. For the 

determination analysis, DOE used the ENERGY STAR delineation whereby wall adapters for electronic products 

such as laptop computers and cellular telephones were considered EPSs. 

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A full list of EPS design parameters that DOE fixed for isolating the impacts of 

efficiency is presented in Table 5.5. In addition to the usability, safety, and interoperability 

parameters already mentioned, the table also includes the yearly manufacturing volume at which 

cost information associated with efficiency improvements was obtained or calculated during the 

engineering analysis. A yearly manufacturing volume was also specified to permit comparisons 

between data from different sources, and to isolate efficiency improvement as the only variable 

under analysis. This volume was 1,000,000 units/year for representative unit A (due to the 

popularity of cellular telephones) and 500,000 units/year for the other two representative units. 

Table 5.5 Additional Characteristics of EPS Representative Units 

Parameter Value 

Input Voltage 

Input Protection 

Output Voltage Regulation 

Output Voltage Ripple 

Transient Response 

Output Protection 

Unit Volume 

Application 

Package 

Output Cord Length 

Regulatory Compliance 

Product Lifetime 

115 volts rms, 60 Hz 

Primary current fuse, inrush current 

limiting 

± 1% (excluding cord) 

1% maximum (peak-to-peak) 

0.5 ms for 50% load change typical 

Overcurrent protection, short-circuit 

protection 

1 M/year for product class A 

500 k/year for product classes B & F 

Information technology/consumer 

electronics 

Sealed polycarbonate 

6 feet 

UL, FCC, 

PFC for PIN > 75 W 

> 2 years 

5.3 Selection of Candidate Standard Levels 

In the determination engineering analysis, selection of CSLs followed the identification 

of representative product classes and representative units, described in section 5.2. Although the 

production cost and manufacturer selling price of a unit would appear in the aggregate as a 

continuous function of efficiency, data for each point along the curve were not available, so DOE 

focused its analysis at discrete efficiency levels, or CSLs. 

CSLs are generally based on (1) efficiencies achievable by commonly used design 

options, (2) voluntary guidelines or mandatory standards already in existence that have prompted 

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manufacturers to develop products at particular efficiency levels, and (3) the max-tech level.3 

For example, DOE often considers the ENERGY STAR level as one CSL, while the least 

efficient models in a product class serve as the baseline CSL. Basing CSLs on established 

guidelines or standards increases the availability of data because manufacturers may have 

already designed products to meet the CSL, and may therefore be able to provide cost 

information. Furthermore, products meeting the CSL may exist in the marketplace and be 

available for testing and teardowns, further strengthening the analysis. 

However, even if CSLs are based on design options in units currently being 

manufactured, they should not be seen as technologically prescriptive. In other words, 

manufacturers are free to use any combination of design options to achieve the efficiency 

specified by a given CSL. To maintain this approach throughout the analysis, DOE specifically 

did not examine CSLs that could only be achieved through proprietary design options not 

available to all manufacturers. 

5.3.1 BC Candidate Standard Levels 

As described in chapter 3, the DOE test procedure references the U.S. Environmental 

Protection Agency’s (EPA) ENERGY STAR “Test Methodology for Determining the Energy 

Performance of Battery Charging Systems,” which combines measurements of maintenance and 

no-battery mode power consumption into an integrated metric called the energy ratio. 

Manufacturers are free to trade off power consumption in one mode versus the other to meet the 

energy ratio requirements imposed by each CSL. The CSLs DOE used in the BC determination 

analysis are presented in Table 5.6. 

As the table shows, DOE did not analyze the cost-efficiency relationship at the max-tech 

CSL due to a lack of data. Instead, DOE increased the level of detail by analyzing data at 

efficiency levels between such established CSLs as ENERGY STAR and baseline. Because DOE 

initially obtained data on a more limited set of CSLs, DOE calculated cost-efficiency data at 

these additional levels through interpolation. 

3

 The max-tech level represents the most efficient design that 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. 

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Table 5.6 BC Candidate Standard Levels by Representative Unit 

CSL 

Energy Ratio 

Representative 

Product 

Class A 

1.2 V, Slow 

Representative 

Product 

Class B 

4.8 V, Slow 

Representative 

Product 

Class C 

18 V, Slow 

Representative 

Product 

Class C 

18 V, Fast 

0 

1 

2 

3 

4 

Baseline 

Above 

Baseline 

ENERGY 

STAR 

Beyond 

Standard 

Best-in-Market 

Technology 

66.5 

27.9 

22.0 

15.0 

8.8 

14.0 

12.3 

11.6 

6.3 

4.5 

13.0 

5.5 

3.8 

2.5 

1.5 

13.0 

5.5 

3.8 

2.5 

1.5 

5.3.2 EPS Candidate Standard Levels 

The CSLs in the determination analysis were specified in terms of DOE’s efficiency 

metrics for EPSs (active mode efficiency and no-load power) and BCs (energy ratio). Because 

both of the efficiency metrics output by the EPS test procedure affect the energy consumption of 

the unit, DOE developed CSLs that included “matched pairs” of limits on both metrics 

simultaneously. 

Matched pairs allowed DOE to base CSLs on existing EPS standards, such as those 

developed by ENERGY STAR or the California Energy Commission (CEC). As these CSL 

matched pairs progress from least to most efficient, either the active mode efficiency or no-load 

power-consumption requirements, or both, increase in stringency. By preventing a decrease in 

the stringency of these metrics, DOE makes a tacit assumption that there is no trade-off between 

EPS performance in the two modes, and increasing the energy savings in one mode does not 

necessarily cause a decrease in energy savings in the other. 

To verify this assumption, DOE analyzed the relationship between active mode efficiency 

and no-load power consumption for products currently in the market. Figure 5.1 plots efficiency 

measurements conducted by DOE on EPSs with nameplate output power around 5 watts and 

60 watts. The figure shows that EPSs with higher active mode efficiencies tend to also have 

lower no-load-mode power consumption. This is probably true only up to a point, however, and 

one can imagine cases in which an EPS manufacturer tries to minimize no-load power, but can 

only do so at the expense of lower active mode efficiency. Therefore, DOE based its matched 

pairs on those currently seen in the market. The CSLs followed—as much as possible—the 

efficiency metrics achieved by actual EPSs at representative-unit output powers and voltages. 

This ensured that for CSLs below max-tech, current EPSs would be able to meet both active 

mode and no-load-mode requirements. 

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0 

0.5 

1 

1.5 

2 

2.5 

No-Load Power [W] 

0–6 Watts Maximum Rated Output Power

40–66 Watts Maximum Rated Output Power 

20% 30% 40% 50% 60% 70% 80% 90% 

Average Efficiency [%] 

Figure 5.1 Comparison of Active Mode Efficiency and No-Load Power; Arrows Point in 

Direction of Increased Efficiency 

DOE evaluated the relationship between EPS cost and efficiency for each representative 

unit at seven CSLs: 

• CSL 0: baseline line-frequency 

• CSL 1: baseline switched-mode 

• CSL 2: meeting CEC Tier 1 

• CSL 3: meeting CEC Tier 2 

• CSL 4: surpassing CEC Tier 2 

• CSL 5: best in market 

• CSL 6: maximum technologically feasible 

In each case, the name of the CSL refers to the standard upon which the CSL is based, or 

indicates the types of EPSs that can generally meet the CSL. For example, switched-mode EPSs 

that contain conventional integrated circuit (IC) pulse-width modulation (PWM) controllers 

without any specific provisions for efficiency are likely to meet CSL 1 (baseline switchedmode), but not CSL 2. 

The active mode efficiency and no-load power requirements corresponding to each CSL 

are listed in Table 5.7. As can be seen, even though the names of the CSLs are the same for each 

representative unit, they correspond to different active mode efficiencies and no-load power 

consumptions. This is because of technological and scaling differences between the 

representative units, highlighted in chapter 3. For example, the EPS design a conventional PWM 

controller (CSL 1) may only achieve 71% efficiency and 1.5 watts of no-load power 

consumption at 18 watts and 12 volts, but it should be able to achieve 78% and 2 watts of noload power when redesigned for 90 watts and 19 volts. DOE did not analyze representative 

unit F at CSL 0 due to a lack of high-power EPSs that use a linear-regulated line-frequency 

design. 

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Table 5.7 EPS Candidate Standard Levels by Representative Unit 

CSL 

Representative Unit 

A 

2.75 W, 5 V 

Representative Unit B 

18 W, 12 V 

Representative Unit F 

90 W, 19 V 

Mini 

mum 

Effici 

ency 

(%) 

Max. NoLoad Input 

Power (W) 

Minimum 

Efficiency 

(%) 

Max. NoLoad Input 

Power (W) 

Minimum 

Efficiency 

(%) 

Max. NoLoad Input 

Power (W) 

0 30 2.00 66 2.00 n/a n/a 

1 55 0.80 71 1.50 78 2.00 

2 58 0.50 75 0.75 84 0.75 

3 59 0.50 76 0.50 85 0.50 

4 65 0.40 80 0.40 87 0.40 

5 72 0.30 85 0.20 89 0.31 

6 75 0.20 88 0.15 92 0.15 

5.4 Manufacturer Interviews 

DOE interviewed eight BC and eight EPS manufacturers to obtain price estimates for 

representative units at the CSLs listed in Table 5.7 and Table 5.6. Following aggregation and 

validation, this price information was combined with efficiency data to form one of the key 

outputs of the engineering analysis. 

The interviews were structured according to the manufacturer surveys presented in 

appendices 5.A and 5.B. In the course of the interview, DOE contractors asked manufacturers to 

provide the costs of reaching each CSL for each representative unit. Manufacturers listed the 

least expensive technology options that met the CSLs and their costs, either as a BOM cost or the 

marked-up MSP. 

Although manufacturers were initially asked about a more limited set of CSLs than those 

listed in Table 5.7 and Table 5.6, they provided additional information on the costs at other 

efficiency levels. Additional CSLs were developed later by fitting curves to data obtained during 

the interviews and interpolating between the points. These CSLs enabled greater resolution in the 

downstream analyses. 

A further caveat was that manufacturers sometimes provided data for products with 

parameters close to, but not the same as, the representative units. This occurred when 

manufacturers had direct experience with a similar unit and could provide cost and efficiency 

data with greater confidence than for the idealized representative unit. In these cases, DOE 

scaled the data the manufacturer provided to align with the representative unit. Although DOE 

could have requested that the manufacturer perform the scaling from manufacturer-supplied unit 

to the representative unit, some manufacturers were reluctant to make statements about BCs or 

EPSs they had designed. By performing the scaling itself, DOE could also use a consistent and 

transparent method. 

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For example, some manufacturers provided data on EPSs that were similar to the 

representative units in terms of capacity, functionality, and design, but had slightly different 

output power or output voltage. DOE then used typical relationships between power and 

efficiency or voltage and efficiency to adjust the efficiency data so that it would apply to the 

representative unit. This normalization accounted for any differences in output power, output 

voltage, volume, and other characteristics, and permitted aggregation of all the manufacturers’ 

cost-efficiency data. Sections 0 and 5.4.9 present the normalization methods for BCs and EPSs, 

respectively. 

5.4.1 BC Manufacturer Interview Overview

 Under non-disclosure agreements, DOE interviewed representatives of several 

consumer-product firms that manufacture battery-powered products. Interviewers asked each 

representative to provide information about technology options for increasing the energy 

efficiency of BCs that ship with their products. The following list shows the number of 

manufacturers that provided data for each representative unit: 

• representative product unit A (personal-care products): 3 manufacturers 

• representative product unit B (small tools and floor care): 4 manufacturers 

• representative product unit C (DIY power tools): 3 manufacturers 

• representative product unit C (professional power tools): 3 manufacturers 

Before each interview, each manufacturer received a Cost-Efficiency Estimation Survey 

(appendix 5.A) to guide their estimates. To ensure consistency among manufacturers, the survey 

specified the parameters of each BC representative unit under consideration (Table 5.1 and Table 

5.2). Although battery chemistry was not specified, most manufacturers provided information for 

nickel-based chemistries (NiMH and Ni-Cd). Although lithium chemistries have lower selfdischarge and may decrease maintenance current, DOE did not expect significant differences in 

BC energy consumption due to the increased safety and monitoring overhead associated with 

lithium batteries. 

The interviewers asked manufacturers to describe the technological improvements for 

each representative unit and associated costs necessary to meet each CSL (section 5.3.1). 

Although the CSLs for battery chargers are specified in terms of energy ratio, the DOE metric of 

non-active energy consumption, the survey presented them as disaggregated maintenance and 

no-battery mode power consumption levels.4

 DOE decided to disaggregate the metrics after 

finding that manufacturers were more responsive to CSLs directly specified in terms of 

maintenance and no-battery mode power consumption. 

DOE recognizes that separating the integrated energy ratio metric and asking 

manufacturers to meet two separate power consumption levels instead of a CSL expressed in 

terms of a single metric risked over-constraining the manufacturers. Because DOE was in effect 

asking them to estimate the costs of meeting standards on power consumption in two distinct 

4

 The energy ratio is calculated as the sum of maintenance mode power, integrated over 36 hours, and no-battery 

power, integrated over 12 hours, divided by the battery energy, measured under a 0.2 C discharge. 

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modes, there was a chance that manufacturers could not make the necessary tradeoffs between 

the two and meet the specified CSL at the lowest cost. 

To mitigate this potential problem, DOE used typical maintenance to no-battery mode 

power consumption of devices currently in the market to disaggregate the energy ratio CSLs. 

When possible, DOE used BC test results5 to select maintenance and no-battery mode power 

consumption of typical BCs that met a particular CSL. DOE then extrapolated additional data 

from related work on EPSs. Table 5.8 lists the resulting maintenance and no-battery mode power 

consumption limits for each CSL. 

As will be presented later (see Figure 5.2), there is actually a moderate correlation 

between BC maintenance and no-battery mode power. This correlation implies that there are 

currently no significant tradeoffs between decreasing power-consumption in one mode versus the 

other, further decreasing the risk that DOE over-constrained manufacturer design options during 

its interviews. 

Table 5.8 Maintenance and No-Battery Mode Power Consumption Levels Used in 

Manufacturer Interviews 

CSL 

Representative Unit 

A 

Representative Unit 

B 

Representative Unit 

C 

Representative Unit 

F 

Maintenance 

Mode 

Power 

[W] 

NoBattery 

Mode 

Power 

[W] 

Maintenance 

Mode 

Power 

[W] 

NoBattery 

Mode 

Power 

[W] 

Maintenance 

Mode 

Power 

[W] 

NoBattery 

Mode 

Power 

[W] 

Maintenance 

Mode 

Power 

[W] 

NoBattery 

Mode 

Power 

[W] 

0 

1 

2 

3 

0.80 0.60 

0.70 0.50 

0.35 0.04 

0.10 0.01 

1.90 0.60 

1.70 0.50 

1.50 0.40 

0.50 0.05 

6.00 1.50 

1.50 0.80 

1.00 0.30 

0.30 0.10 

4.70 2.10 

4.00 1.80 

3.00 1.00 

1.20 0.10 

5.4.2 BC Manufacturer Interview Responses and Preferred Design Options 

Representative unit A models battery chargers for such small, low-voltage consumer 

product applications as shavers and beard trimmers. Because of the low battery voltage and small 

battery capacity, these BCs have a very low output power, and are typically composed of a linefrequency center-tapped transformer followed by a full-wave rectifier. Battery charge control is 

performed through current limiting with a discrete resistor or the winding resistance of the 

transformer. 

The BC described above would charge the battery in 10 or more hours. To decrease the 

charge time, some manufacturers replaced the slow BC’s line-frequency power supply with a 

switched-mode power supply, which permits the same size package to deliver higher output 

power, resulting in faster charging. This development also improved the efficiency of the power 

supply, both due to the higher efficiency of the switched-mode power supply and the need for 

5

 DOE used its own test results as well as datasets provided by Ecos Consulting (a CEC contractor) and ENERGY 

STAR. 

5-14
 

EERE-2008-BT-STD-0005 COMMENT 03
 

termination when charging at a higher rate. A list of technology improvements that 

manufacturers suggested during interviews appears below. 

•	 CSL 0: line-frequency transformer, center-tapped rectifier, standard p-n junction rectifier 

diodes, current-limiting resistor or winding resistance 

•	 CSL 1: same design as CSL 0, but with improved transformer core, Schottky rectifier 

diodes 

•	 CSL 2: switched-mode power supply 

•	 CSL 3: switched-mode power supply with improved components 

•	 CSL 4: not available 

Representative unit B models battery chargers for household appliances, such as kitchen 

tools, floor-care products, and small power tools that are typically packaged with integral 

batteries, such as cordless screwdrivers. As for representative unit A, these devices are used 

infrequently enough that users do not require a fast recharge, so they typically ship with slow 

chargers. However, as for representative unit A, some higher-end manufacturers have begun 

packaging products with fast chargers, which require switched-mode power supplies and 

therefore tend to be more efficient than slow chargers, which use line-frequency power supplies. 

According to manufacturers interviewed during the determination analysis, the 

technology options for improving the efficiency of representative unit B are similar to those for 

representative unit A. Because of the higher battery voltage of representative unit B, more power 

is delivered to the battery during maintenance mode, leading to higher charger power 

consumption during that mode. As a result, termination, or significant reduction of current into 

the battery during maintenance, becomes a bigger concern. Manufacturers proposed sensors and 

timers as a way of limiting power consumption in maintenance mode. A list of manufacturersuggested technology options for representative unit B appears below. 

•	 CSL 0: line-frequency transformer, center-tapped rectifier, standard p-n junction rectifier 

diodes, current-limiting resistor or winding resistance 

•	 CSL 1: same design as CSL 0, but with improved transformer core, Schottky rectifier 

diodes 

•	 CSL 2: same design as CSL 1, but with timer or other termination circuitry 

•	 CSL 3: switched-mode power supply 

•	 CSL 4: switched-mode power supply with improved components 

Representative unit C models slow, higher-voltage BCs that typically ship with power 

tools for DIY use. Because the architecture of this charger is similar to representative unit B, the 

technology options for efficiency improvement are generally similar as well. However, due to 

the much higher battery voltage6

 and consequent battery charger output power, certain 

technology options result in much greater savings than in the case of representative unit B. For 

example, the amount of power delivered to the primary side of a line-frequency power supply 

can be controlled with the use of a phase-control circuit, limiting the power dissipated in the 

transformer core. A list of some of the typical technology options that manufacturers identified 

for representative unit C appears below. 

6

 Representative unit C has an 18-volt battery, compared to the 4.8-volt battery of representative unit B. 

5-15
 

EERE-2008-BT-STD-0005 COMMENT 03
•	 CSL 0: line-frequency transformer, center-tapped rectifier, standard p-n junction rectifier 

diodes, current-limiting resistor or winding resistance 

•	 CSL 1: same design as CSL 0, but with improved transformer core 

•	 CSL 2: same design as CSL 1, but with timer or other termination circuitry and/or 

primary-side phase control 

•	 CSL 3: switched-mode power supply 

•	 CSL 4: switched-mode power supply with improved components, termination, and/or AC 

switch during no-battery mode 

Representative unit D is also typically used for charging power-tool batteries. This unit 

differs from the power tool chargers described previously because the application—professional 

power tools—gets frequent use and requires frequent recharging. As a result, the BCs are fast 

chargers, with charge rates typically at or above 1 C. 

Because the output power of a BC is directly proportional to the charge rate, professional 

power-tool fast chargers can have output power an order of magnitude higher than the slow 

chargers modeled by representative product unit C. Therefore, the following technology options 

differ significantly from those discussed for the other representative units: 

•	 CSL 0: switched-mode power supply and charge controller, or line-frequency transformer 

followed by silicon-controlled rectifiers (SCRs) 

•	 CSL 1: switched-mode power supply, but with improved components 

•	 CSL 2: same design as CSL 1, but with improved power supply compensation 

•	 CSL 3: same design as CSL 2, but with lower power consumption during maintenance 

mode 

•	 CSL 4: same design as CSL 3, but with improved startup circuit, synchronous 

rectification, and/or automatic AC-side switch during no-battery mode 

5.4.3 BC Manufacturer Interview Data Analysis 

During interviews, manufacturers followed the power consumption levels contained in 

the survey only loosely. When responding, they typically considered a unit currently under 

production as the baseline, reporting its measured power consumption in maintenance, nobattery, and in some cases, active mode. They then speculated on methods for improving the 

baseline unit, such as improving components, adding or exchanging subcircuits, or redesigning 

the topology. They accompanied each set of improvements with the increased costs over the 

baseline as well as incremental gains in efficiency, again expressed in terms of power consumed 

during the three modes of operation. 

DOE calculated a non-active energy ratio from the maintenance and no-battery mode 

power consumption provided by manufacturers. To represent active mode energy consumption, 

DOE used integrated, 24-hour, active and maintenance mode energy consumption that 

represents consumption experienced by a typical user over a 24-hour charging cycle. 

Manufacturers, however, expressed the active mode performance of their BCs in terms of power 

consumption during active mode, if at all. DOE therefore calculated the 24-hour integrated 

energy consumption figure using the following formula: 

5-16
 

EERE-2008-BT-STD-0005 COMMENT 03
1 1 E = P + (24hr − )P , 24 ACTIVE MAINT

rη CELL rη CELL 

Eq. 5.1 

where: 

r is the charge rate of the BC in units of 1/hours; 

η CELL is the cell efficiency, assumed to be 80 percent; 

PACTIVE is the power consumption of the BC in active mode while charging the battery; and 

PMAINT is the power consumption of the BC in maintenance mode after the battery has been fully 

charged. 

As Equation 1 shows, DOE used the BC’s charge rate to calculate the charge time, which 

also depends on the cell efficiency of the battery being charged. During the remainder of the 24 

hours, DOE assumed the charger to be in maintenance mode. Most manufacturers, however, only 

provided estimates of power consumption in maintenance mode, not in active mode. 

When manufacturers did not provide the active mode power consumption, DOE 

estimated this metric in one of two ways. If the charger was a slow charger and no additional 

information was available, DOE substituted the maintenance mode figure for active mode power 

consumption because of the lack of clear distinction between active mode and maintenance mode 

in slow chargers. If the manufacturer provided BC “efficiency,” defined as the power delivered 

to the battery over the power consumed, DOE calculated the active mode power consumption 

from the power required to charge the battery, divided by this BC efficiency. In either case, these 

calculations allowed DOE to estimate the typical energy consumption of a BC in all three modes. 

5.4.4 Supplements to BC Manufacturer Interview Data 

Although some of the consumer-product manufacturers DOE interviewed designed BCs 

for their products in-house, many acquired their BCs from outside vendors. These manufacturers 

were therefore unable to provide detailed information about the design options necessary to meet 

the CSLs or even to decrease energy consumption in the three modes. 

This lack of familiarity with energy efficient design prevented many manufacturers from 

providing detailed power consumption estimates in the three modes of BC operation. They were 

often able to supply only two cost-efficiency points, one before and one after the enactment of 

California’s Title 20 appliance efficiency standards for EPSs, which affected some BCs. Because 

many slow BCs fell under the California Energy Commission (CEC) definition of EPSs, many 

manufacturers had to ensure their products complied with these standards, which went into effect 

July 1, 2007. 

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EERE-2008-BT-STD-0005 COMMENT 03
Nonetheless, the burden of redesigning for compliance remained with the outside BC 

vendors, and some of the manufacturers interviewed could not offer more detail than the CEC 

compliance status of the wall adapter. Where manufacturers could not provide detailed efficiency 

data, DOE sought to acquire the specific units described by the manufacturer, performing 

efficiency tests and using that information to fill in gaps in the data. 

When DOE could not purchase the requisite BC and therefore no direct substitution of 

measurement results was possible, DOE averaged the performance of the wall adapter 

components of other BCs in its test database that were in the same product class. DOE then 

paired these averages with the manufacturer costs to arrive at an estimate of the manufacturer’s 

cost-efficiency relationship. 

Table 5.9 Product Class-Average BC Wall Adapter No-Load Power Consumption 

Product 

Class 

Voltage 

Range 

Non-CEC Compliant CEC Compliant 

Number of 

Adapters 

Class-Average NoLoad Power [W] Number of 

Adapters 

Class-Average NoLoad Power [W] 

A 

B 

C 

0 V–3 V 

3 V–9 V 

9 V–36 V 

4 0.93 

20 0.81 

4 1.13 

0 – 

6 0.15 

2 0.35 

Manufacturers, however, only specified whether the BC’s wall adapter component had 

met the CEC EPS standard based on its active mode efficiency and no-load power, as measured 

by the EPS test procedure. Because nothing more was known about these units, DOE had to 

extrapolate from the wall adapter to the entire BC system, by estimating the energy consumption 

in all three BC modes based on the average BC wall-adapter no-load power consumption in 

Table 5.9. 

Figure 5.13 shows, however, that no-load power consumption is a fairly good predictor of 

battery charger power consumption in no-load and maintenance modes. DOE therefore used the 

relationship between the two metrics to estimate class-average no-load- and maintenance mode 

power consumption for pre- and post-CEC BCs. Again, because these were slow chargers 

without a clear distinction between maintenance and active modes, DOE substituted maintenance 

mode power consumption for active mode power consumption. The resulting three average 

metrics appear in Table 5.10. 

5-18
 

EERE-2008-BT-STD-0005 COMMENT 03
 Maintenance or No-Battery Power [W] 

3.00 

2.50 

2.00 

1.50 

1.00 

0.50 

0.00 

y = 1.0023x 

R2

 = 0.9896 

y = 2.1306x + 0.4198 

R2

 = 0.6386 

No-Battery Power w/o Outliers 

Maintenance Power w/o Outliers 

0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 

EPS No-Load Power [W] 

Figure 5.2 Relationship Between BC Wall-Adapter No-Load Power and System NoBattery and Maintenance Power 

Table 5.10 Average Calculated BC Performance Used to Supplement Manufacturer Data 

Product 

Class 

Voltage 

Range 

Non-CEC Compliant CEC Compliant 

Maint. 

Mode 

Power 

[W] 

NoBattery 

Power 

[W] 

24-Hour 

Charge and 

Maint. Energy 

[Wh] 

Maint. 

Mode 

Power 

[W] 

NoBattery 

Power 

[W] 

24-Hour 

Charging and 

Main. Energy 

[Wh] 

A 

B 

C 

0 V–3 V 

3 V–9 V 

9 V–36 V 

2.36 0.93 56.56 

2.10 0.81 50.49 

2.77 1.13 66.39 

1.067

0.76 

1.15 

 0.307

 25.397 

0.15 18.15 

0.35 27.61 

5.4.5 Scaling of BC Manufacturer Interview Data to Representative Units 

Following the collection of data from the manufacturers and supplementation with test 

results, DOE scaled the cost-efficiency data, aligning them with the representative units to permit 

aggregation of data from various sources. As described earlier, manufacturers often based their 

data submission on actual BCs currently in production. These did not always have the same 

specifications as the representative units, but were similar enough that DOE could scale the 

power consumption estimates provided by manufacturers to be applicable to the representative 

units. 

For example, the BC upon which a manufacturer had based its data submission could 

have been charging a battery with a capacity twice that of the closest representative unit. In this 

case, DOE calculated what the energy consumption would have been had the battery capacity 

7

 Since no data were available on low-voltage CEC-compliant chargers (Table 5.9), DOE assumed a moderate noload power consumption value of 0.3 W. 

5-19
 

EERE-2008-BT-STD-0005 COMMENT 03
 

 

been decreased to that of the representative unit, keeping all other characteristics of the design 

constant. 

Only the maintenance and no-battery mode power consumption metrics were scaled to 

the representative units. DOE did not scale the active mode power consumption or the 24-hour 

integrated active and maintenance mode energy consumption because of the excessive 

complexity of modeling the effects of unit parameters on active mode performance and the lack 

of empirical data upon which to base a simpler, linearized model. 

DOE scaled the maintenance mode power consumption by the ratio of the battery 

voltages of the representative unit and the manufacturer-described unit as follows: 

V ′ P′ = B

MAINT MAINT P , VB 

Eq. 5.2 

where the primed quantities pertain to the representative unit. 

Since a maintenance current into a battery of a higher voltage results in proportionally 

higher power into the battery, DOE modeled the change in the maintenance mode power 

consumption as proportional to the ratio of battery voltages. DOE did not include a dependence 

on battery capacity after learning from manufacturers that the maintenance current into the 

battery is typically held constant by the BC and does not vary with battery capacity, even though 

higher-capacity batteries will have a higher self-discharge current, and should compensate with a 

higher maintenance current. DOE also did not include a dependence on charge rate, as 

maintenance mode power consumption did not depend on charge rate.8 

No-battery mode power consumption was likewise scaled, using the following equation: 

VB ′CB ′ r′

2 3 

P′ = 

  P , NO _ BATTERY NO _ BATTERY V C r  B B 

Eq. 5.3 

where: 

VB is the battery voltage; 

CB is the battery capacity, expressed in ampere-hours; 

8

 Chargers of 1 C and 2 C (where C is the unit of charge rate equivalent to 1/hour) made by the same manufacturer 

are likely to have the same maintenance current, and therefore maintenance mode power consumption, as the 

operational characteristics of the BC in active and maintenance modes are specified independently. 

5-20
 

EERE-2008-BT-STD-0005 COMMENT 03
r is the charge rate or the charge current divided by the battery capacity, expressed in units of C 

or 1/hour; and 

all primed quantities refer to the representative unit. 

Most no-battery mode power consumption in a slow battery charger can be attributed to 

magnetization and winding losses in the line-frequency transformer, which typically scale in 

relation to its volt-ampere (VA) rating, raised to the 2/3 power. Furthermore, in a battery charger, 

the volt-ampere rating of the transformer is determined by the peak power delivered to the 

battery during active mode, which is the product of the battery voltage, battery capacity, and the 

charge rate. Although this scaling of no-load power consumption should also affect maintenance 

mode power consumption because transformer losses are always present, the scaling model did 

not account for this second-order effect. 

5.4.6 BC Manufacturer Markups 

The BOM costs manufacturers provided incorporate only a portion of the full production 

cost. Full production cost is defined as the sum of direct material, direct labor, and overhead 

(including investment depreciation). Other cost elements (sales, general and administrative, 

research and development, interest, and profit) comprise the non-production costs. Together 

these costs make up the full cost, or manufacturer’s selling price, of a product (Figure 5.3). 

Figure 5.3 Full Cost of Product: Breakdown of Production and Non-Production Costs 

In addition to the electronics, the direct material costs also include the BC’s plastic 

enclosure, AC or DC cord, and mechanical components such as contacts and springs. For the 

determination analysis, DOE assumed that the costs of these components would stay constant as 

efficiency improved and would not scale in proportion to the electronics BOM cost, in contrast 

with production overheads such as direct labor. 

Figure 5.11 shows the relationship between the two types of direct material costs, the 

other production cost (consolidated into a single production markup), and the non-production 

costs (another markup). DOE used the typical values in Figure 5.11, aggregated from data 

obtained during manufacturer interviews, in conjunction with this markup chain to scale 

manufacturer-provided electronics BOM costs to MSP. 

5-21
 

EERE-2008-BT-STD-0005 COMMENT 03
Figure 5.5 Markup Chain Diagram for Battery Chargers 

Table 5.11 Typical Markups and Add-Ons for Each BC Representative Unit 

Electronics 

BOM Cost 

Production 

Cost 

Markup 

Mechanical 

Component 

Add-On 

NonProduction 

Markups 

× + × = 

Manufacturer’s 

Selling Price 

Representative 

Unit 

Electronic 

Component 

Production 

Markup 

Case, Cord, and 

Mechanical 

Components 

Add-On 

Total Non-Production 

Markups (Includes 

Corporate, Shipping, 

and Tariffs) 

A 

B 

C 

D 

28% 

28% 

32% 

32% 

$0.24 

$0.40 

$0.73 

$1.50 

92% 

77% 

63% 

63% 

5.4.7 EPS Manufacturer Interview Overview 

Between October and December 2008, DOE conducted interviews and received data 

from manufacturers of EPSs and manufacturers of integrated circuits (ICs) for EPSs. Each 

manufacturer reviewed DOE’s methodology and assumptions, and in addition to cost-efficiency 

data, supplied DOE with information about the EPS design process, the structure of the supply 

chain, production volumes, and related issues. 

The manufacturer survey (appendix 5.B) sought to obtain estimates of the MSP paid to 

the manufacturer by distributors or OEMs for representative-unit EPSs at each CSL. To develop 

a more accurate price estimate, DOE also asked manufacturers to list and cost the design options 

they would use to meet the CSLs. The consensus views for each representative unit follow. 

5.4.8 EPS Manufacturer Interview Responses and Preferred Design Options 

Representative unit A models EPSs with nameplate output power intended for such 

applications as charging cellular or cordless telephones or powering small appliances. Because of 

the popularity of cellular telephones, EPSs in product class A are typically sold in large volumes 

but, because of the high degree of competition, are subject to smaller manufacturer markups. 

Portability also affects the cost-efficiency relationship of representative unit A. The lower 

the power, the smaller the transformer in a baseline line-frequency EPS, and the lower the costs 

associated with the steel core and copper windings. Throughout representative product class A, 

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EERE-2008-BT-STD-0005 COMMENT 03
 

switched-mode designs cost significantly more than line-frequency designs, which would be 

universally adopted were it not for the need for portability. Because consumers demand smaller, 

more portable EPSs for charging cellular telephones while traveling, manufacturers use 

switched-mode power supplies9

 for this application, by far the biggest in terms of volume. This 

change in design from line-frequency to switched-mode also decreases the energy consumption 

of the EPS, allowing it to meet CSL 1. Manufacturers provided the following list of design 

options that are necessary for the representative unit to meet each CSL: 

•	 CSL 0: line-frequency transformer, Schottky rectifier diodes 

•	 CSL 1: switched-mode EPS with standard IC PWM controller or ringing-choke controller 

•	 CSL 2: switched-mode EPS with energy-efficient IC PWM 

•	 CSL 3: same design as above, with improved components 

•	 CSL 4: same design as above, with improved components 

•	 CSL 5: switched-mode EPS with zero-voltage switching, lower-resistance field-effect 

transistor (FET) switch, more copper in choke 

•	 CSL 6: not available 

The representative unit for product class B has a nameplate output power of 18 watts and 

output voltage of 12 volts. This unit is typically used to power household networking appliances 

such as modems or other computer peripherals. Because of the immobility of these devices, there 

has been no strong pressure on manufacturers to produce smaller and lighter EPSs. During the 

determination analysis, the typical EPS in product class B featured a line-frequency design, 

which at this output power tended to still be less expensive than an equivalent switched-mode 

design. A switched-mode design, however, would be necessary for meeting CSL 1, as the 

following list of design options—suggested by a consensus of manufacturers during 

interviews—shows. 

•	 CSL 0: line-frequency transformer, standard rectifier diodes 

•	 CSL 1: switched-mode EPS with standard IC PWM controller 

•	 CSL 2: switched-mode EPS with energy-efficient IC PWM 

•	 CSL 3: same design as above, with improved components 

•	 CSL 4: same design as above, with improved components 

•	 CSL 5: better core material, improved FET switch 

•	 CSL 6: synchronous rectification, resonant snubbers, zero-voltage/zero-current switching 

The final representative unit analyzed during the determination analysis (for product 

class F) has a nameplate output power of 90 watts and output voltage of 19 volts. The main 

application of this high-power device is supplying laptop computers and video-game consoles. 

Throughout product class F, it is no longer practical to produce line-frequency EPSs due to the 

large size of the transformer and high cost of the necessary steel and copper. Therefore, even 

though DOE did not consider line-frequency designs applicable for this representative unit, 

9

 Switched-mode power supplies are smaller and lighter than line-frequency designs at the same nameplate output 

power. 

5-23
 

EERE-2008-BT-STD-0005 COMMENT 03
 

 

 

CSL 0 was reserved in the analysis for consistency with the other representative units. The 

design options necessary for meeting the other CSLs are listed below. 

• CSL 0: not applicable 

• CSL 1: switched-mode EPS with standard IC PWM controller 

• CSL 2: switched-mode EPS with energy-efficient IC PWM 

• CSL 3: same design as above, with improved components 

• CSL 4: same design as above, with improved components 

• CSL 5: better core material, more copper, improved components 

• CSL 6: synchronous rectification, resonant snubbers, zero-voltage/zero-current switching 

5.4.9 Scaling of EPS Manufacturer Interview Data to Representative Unit Volume 

After marking up the BOM costs to arrive at manufacturer selling prices, DOE had to 

further adjust the individual manufacturer prices to a common yearly volume. Although 

manufacturers were asked to provide their prices at a common volume, not all were able to do so. 

Therefore, DOE marked up or marked down the MSP, as appropriate, to arrive at commonvolume prices that were comparable to one another. Table 5.12 presents these common volumes 

and the rate DOE used to scale the prices according to volume. 

Table 5.12 Unit Volumes and Volume Discount Rates for Each EPS Representative Unit 

Representative 

Unit Volume of Representative Unit 

Per-Decade Discount Rate 

(percent) 

A 

B 

C 

1,000,000 units/year 

500,000 units/year 

500,000 units/year 

17.7 

17.7 

17.7 

The discount rate DOE used to scale prices across decades (i.e., factors of ten) of volume 

was based on MSPs for 2-watt and 5-watt switched-mode EPSs reported by the manufacturer 

Ten Pao in a public comment submitted by the Natural Resources Defense Council to the 

California Energy Commission during the 2006 Appliance Efficiency Standards rulemaking.10 

Table 5.13 shows the prices and discount-rate calculations, which result in an average volume 

discount rate of 17.7 percent per decade. 

10 This comments is available at 

www.energy.ca.gov/appliances/2006rulemaking2/documents/comments/NRDC.PDF. 

5-24
 

EERE-2008-BT-STD-0005 COMMENT 03
 

 

 

Table 5.13 Volume Prices Used to Calculate Average per-Decade Discount Rate 

Quantity 

[Units/Year] 

2 W EPS 

Manufacturer 

Selling Price 

at Quantity 

[$] 

Percentage 

Difference 

from 2 W 

Price at 

Next-Lowest 

Volume 

Percentage 

Difference 

in 2 W 

Price per 

Decade 

5 W EPS 

Manufacturer 

Selling Price 

at Quantity 

[$] 

Percentage 

Difference 

from 5 W 

Price at 

Next-Lowest 

Volume 

Percentage 

Difference 

in 5 W 

Price per 

Decade 

50,000

100,000 

1,000,000 

10,000,000 

 1.65 

1.50 

1.35 

1.20 

– 

-09.1 

-10.0 

-11.1 

– 

-30.2 

-10.0 

-11.1 

2.10 

1.89 

1.60 

1.50 

– 

-10.0 

-15.3 

 -6.3 

– 

-33.2 

-15.3 

-6.3 

Average -17.1 -18.3 

Average across 2 W and 5 W Units -17.7 

5.4.10 Scaling of EPS Manufacturer Interview Data to Representative Unit Power 

Similarly to how it scaled manufacturer-provided data to the volume of the representative 

unit, DOE also scaled data to the power of the representative unit. Although manufacturers 

provided data on units within the same representative product class, not all manufacturers 

produce EPSs with 90-watt nameplate output power or 19-volt output voltage. Therefore, both 

the price and efficiency data they provided had to be scaled to the representative unit output 

power to account for the fact that higher-power units tend to be not only more expensive, but 

also more efficient. 

To determine the dependence of cost on output power, DOE examined an EPS 

manufacturer’s price list, obtained under a confidentiality agreement. The price charged by the 

manufacturers to distributors seemed to be proportional to the output power, across a wide range 

of efficiencies and spanning output powers from 4 watts to 150 watts. DOE used the slope of the 

least-squares line passing through the points, with an R2

 value of 0.984, to scale the costs to the 

output powers of the representative unit. 

Because the practically achievable efficiency of an EPS also depends on the output 

power, DOE expects that shifting the manufacturer-provided cost-efficiency data to the output 

power of the representative unit would result in a change in active mode efficiency. Figure 5.6 is 

a schematic representation of the EPS efficiency distribution with power, which shows the 

general trend in EPS. DOE therefore assumed that if a manufacturer were to design two similar 

EPSs with slightly different powers, the efficiency of the higher-power EPS would be higher, 

and vice versa. However, there is a wider range of efficiency at low output power than at high 

output power. Any shift of a manufacturer’s unit to the representative unit output power should 

therefore preserve a unit’s relative standing in terms of efficiency among other units in the 

market. 

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EERE-2008-BT-STD-0005 COMMENT 03
ENERGY STAR demarcates the 75th 

percentile of efficiency. 

Efficiency [%] 

Pout_max [W] 

Figure 5.6. Schematic Illustration of the Distribution of Efficiency Versus Maximum 

Rated Output Power; the ENERGY STAR Level Is Shown as a Pink Line, while the Blue 

Background Indicates Where Most of the Units Lie 

To preserve the relative standing of the manufacturer’s unit in the market, while shifting 

the results to the representative unit output power, DOE maintained the ratios among the unit’s 

efficiency, the ENERGY STAR level, and the best-in-market level. Figure 5.8 shows how DOE 

generated the best-in-market curve-fit using data on the highest-performing units taken from the 

ENERGY STAR qualifying products database. Since no correlation has been found between noload power and output power, DOE did not scale the no-load power. 

5-26
 

EERE-2008-BT-STD-0005 COMMENT 03
Efficiency [%] 

η BEST_IN_MARKET 

η′

MFR_UNIT 

η ENERGY_STAR 

η MFR_UNIT 

Shift 

PMFR_UNIT PREP_UNIT 

Pout_max [W] 

Figure 5.7. Schematic Illustration of Scaling EPS Efficiency with Output Power 

0% 

10% 

20% 

30% 

40% 

50% 

60% 

70% 

80% 

90% 

100% 

0 50 100 150 200 250 

Rated Output Power [W] 

Conversion Efficiency

Highest performing units 

ENERGY STAR v. 1.1 level 

Best-in-market level 

Worst-in-market level 

Figure 5.8. ENERGY STAR Level and Calculated Best-in-Market and Worst-in-Market 

Curves 

5-27
 

EERE-2008-BT-STD-0005 COMMENT 03
DOE performed the shift in efficiency relative to the best-in-market and ENERGY STAR 

levels using the following equations: 

η′ =η′ − r ⋅(η′ −η′ MFR _ UNIT BEST _ IN _ MARKET BEST _ IN _ MARKET ENERGY _ STAR )

Eq. 5.4 

and 

η BEST _ IN _ MARKET MFR −η _ UNIT 

r = , η BEST _ IN _ MARKET −η ENERGY _ STAR 

Eq. 5.5 

where: 

η MFR _ UNIT , η BEST _ IN _ MARKET , and η ENERGY _ STAR are the efficiencies of the unit under analysis, 

the best-in-market point, and the ENERGY STAR level, respectively, at the 

manufacturer-provided nameplate output power, while 

the primed terms refer to the same quantities at the nameplate output power of the representative 

unit, to which the unit efficiency is being scaled, and 

r is a scaling ratio that represents the position of the efficiency of the manufacturer-provided unit 

to that of other EPSs in the market. 

5.4.11 Scaling of EPS Manufacturer Interview Data to Representative Unit Voltage 

After scaling manufacturer-provided cost-efficiency data to account for any differences in 

output power, DOE scaled the efficiency to account for any differences in output voltage. As 

mentioned in chapter 3, for a given output power, EPS output voltage has a strong effect on 

efficiency because of conduction losses and rectifier voltage drops. 

By testing families of EPSs produced by the same manufacturer with the same nameplate 

output power but different voltage, DOE was able to establish a relationship between voltage and 

efficiency. The relationship is illustrated in Figure 5.9, which shows the results of tests 

conducted on four pairs of EPSs with nameplate output power of 60 watts. Each pair was part of 

the same product family, and included a 12-volt unit and another unit with an output of 18 volts 

or 24 volts. The gains in efficiency due to increasing the output voltage are described well by a 

best-fit line with an R2 value of 0.914; DOE used the slope of the line to scale the manufacturerprovided efficiency data. 

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EERE-2008-BT-STD-0005 COMMENT 03
y = 0.0023x - 0.0275 

R2 = 0.9137 

0% 

1% 

2% 

3% 

4% 

0 5 10 15 20 25 30 

Voltage [V] 

Gain in Efficiency over 12 V 

Figure 5.9 Relationship Between Output Voltage and Efficiency 

While EPS output voltage has a pronounced effect on efficiency, available literature 

suggests and manufacturer interviews confirm that output voltage does not influence EPS price. 

Therefore, DOE did not scale the price with voltage as it had done for efficiency. 

5.4.12 EPS Manufacturer Markups 

Although the output of the engineering analysis is the MSP of the representative units at 

each CSL, some manufacturers did not provide it during the interviews. Instead, they focused on 

what they knew most intimately and reported the total BOM cost, which in contrast with the BC 

interviews, included both electronic components and mechanical hardware and packaging. DOE 

therefore asked additional questions to construct an appropriate model of manufacturer markups 

and obtain the MSP from the BOM cost. 

As in the description of BC markups in section 5.4.6, manufacturer markups fall into two 

categories: production and non-production markups (Figure 5.5). Low and high estimates for the 

two types of markups, constructed from averages of data provided by manufacturers during 

interviews, appear in Table 5.14. To obtain the MSP of a representative unit, DOE multiplied the 

BOM cost first by the production markup and then by the non-production markup appropriate to 

that representative unit. Because EPS manufacturers provided a total BOM cost, DOE did not 

have to apply a separate mechanical component add-on, as during the BC analysis. 

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EERE-2008-BT-STD-0005 COMMENT 03
Table 5.14 Manufacturer Markups Used in the EPS Engineering Analysis 

Representative 

Typical Production 

Markup (%) 

Typical NonProduction 

Markup (%) 

Average Total 

Manufacturer 

Markup (%) 

Unit Low High Low High Low High 

A 

B 

F 

18 37 

24 39 

24 39 

18 25 

18 30 

18 30 

45 74 

47 81 

47 81 

Following the markups and scaling described above, the manufacturer-provided MSPs at 

each CSL were validated through DOE testing and teardowns. The MSPs and CSLs served as 

inputs into subsequent analyses. 

5.5 Efficiency Testing and Teardowns 

To validate data manufacturers provided during interviews (section 5.4.7), DOE conducted 

tests and teardowns of commercially available BCs and EPSs. The tests and teardowns also 

served to validate publicly available efficiency data and identify common EPS design features in 

support of the product classes described in chapter 3. 

DOE conducted the efficiency tests in accordance with its BC and EPS test procedures, 

as codified in appendices Y and Z of subpart B to 10 CFR part 430. DOE also disassembled 

numerous BCs and all 46 of the purchased EPSs, noting the defining features of their circuits. 

DOE also tore down a subset of these units to evaluate the relationship between cost and 

efficiency among units with comparable design characteristics. The teardowns involved a 

detailed parts count and cost estimate (sections 5.5.2 and 5.5.4). Because it is not possible to 

purchase and test models with the maximum technologically feasible efficiency, DOE was only 

able to examine devices with efficiencies between baseline and best-in-market. 

5.5.1 BC Testing 

In September 2007, DOE purchased 29 battery chargers for testing and teardown. The 

BCs were purchased either as part of a kit that included a battery-operated consumer product and 

battery or independently of the product and packaged with just the battery. 

DOE performed the testing and teardowns to achieve the following goals, listed from 

general to specific: 

1.	 gain an understanding of BCs and battery-powered products in the market today, 

2.	 evaluate the DOE and CEC BC test procedures, and also test BC wall adapters using the 

DOE EPS test procedure, 

3.	 validate efficiency test data stakeholders provided in comments to DOE, and 

4.	 validate efficiency and cost data manufacturers provided during interviews. 

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EERE-2008-BT-STD-0005 COMMENT 03
 

The BCs purchased for testing spanned a wide range of applications and voltages and 

were selected for the apparent popularity of the products with which they were sold,11 ensuring a 

sample typical of the market. 

Figure 5.10 shows the results of the efficiency tests conducted on the BCs, expressed in 

terms of energy ratio. The consumer product applications served by the BCs are also indicated on 

the plot, confirming the typical voltage-based divisions described in chapter 3. Figure 5.11 

superimposes the results of DOE’s efficiency data on CEC test data gathered by its contractor, 

Ecos Consulting, showing general agreement between DOE test data and that gathered during 

prior tests. 

0 

10 

20 

30 

40 

50 

60 

70 

Energy Ratio 

Shavers 

Universal BC 

Floor Care 

Power Tools 

Other 

0 5 10 15 20 25 

Voltage [V] 

Figure 5.10 DOE Battery Charger Test Results by Consumer Product Application 

11 DOE evaluated popularity based on the product’s sales rank on retailer websites and ConsumerReports.com. 

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EERE-2008-BT-STD-0005 COMMENT 03
 

0 

10 

20 

30 

40 

50 

60 

70 

80

Energy Ratio 

Ecos Test Results 

DOE Test Results 

0 5 10 15 20 25 30 

Voltage [V] 

Figure 5.11 DOE Battery Charger Test Data Superimposed over CEC Data gathered by 

Ecos Consulting 

5.5.2 BC Teardowns 

Following efficiency testing, DOE tore down the purchased BCs to evaluate costs. The 

process began with the disassembly of the battery chargers, and when any battery charging 

circuitry resided outside the charger, the associated consumer products itself. Following 

disassembly, DOE listed all the electronic components pertaining to battery charging. As 

explained in section 5.2.1, the batteries were excluded from the analysis. 

To aid in the next step, DOE compiled a master list of component costs taken from two 

online electronic component distributors12 at quantities of 1,000 pieces. For components that 

were either unmarked or unavailable in the manufacturer catalogs (e.g., magnetic components), 

DOE estimated their costs based on the costs of parts with similar specifications, construction, 

weight, and materials. Appendix 5.C provides an example teardown analysis report. 

Although DOE purchased 29 BCs, not all were comparable to the four representative 

units described in section 5.2.1.Therefore, DOE only tore down the 11 units that could be 

immediately used to validate or complete the cost-efficiency data manufacturers supplied. The 

results of the teardowns appear in Figure 5.12, which plots BOM cost versus energy ratio for 

each unit. Data points of different cost and shape denote different battery voltages. 

Although there are some outliers, Figure 5.12 shows a clear pattern for BCs with the 

same output voltage. For example, the BOM cost of a 6-volt unit with an energy ratio of 2.4 is 

12 The Digi-Key catalog can be viewed at www.digikey.com. The Mouser catalog can also be viewed at 

www.mouser.com. 

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EERE-2008-BT-STD-0005 COMMENT 03
 

greater than $5, while the costs of two other less efficient units, as well as a comparable 4.8-volt 

unit, with energy ratios between 7 and 11, are around $0.50. 

$0.00 

$1.00 

$2.00 

$3.00 

$4.00 

$5.00 

$6.00 

$7.00 

$8.00 

$9.00 

BOM Cost [USD]

1.2 V 

2.4 V 

4.8 V 

6 V 

18 V 

0 5 10 15 20 25 30 35 40 

Energy Ratio 

Figure 5.12 Low-Volume Cost Versus Efficiency for Tested and Torn-Down Battery 

Chargers 

Although DOE had not thoroughly analyzed the outliers at the time the determination 

analysis was rescheduled in December 2007, one possible explanation may lie in the BC charge 

rate. The more expensive units are all fast chargers that charge the battery in up to one-tenth the 

time of the slow chargers, requiring higher charger output power and more expensive 

components capable of handling the higher power. There are numerous such complicating 

factors, such as the ability of a BC to double as an EPS in a “cord-cordless” product; additional 

circuitry in multi-voltage or multi-port chargers; and proprietary designs that may distinguish 

products by different manufacturers, especially at the higher charge rates and costs. 

One of the goals of the first round of BC testing and teardowns was to identify these sorts 

of dependencies, though further BC purchases may be necessary to establish a clearer 

relationship between cost and efficiency, independent of the complicating factors mentioned 

above. Nonetheless, because there was significant overlap between the units torn down and those 

described by manufacturers (section 5.4), the results of the tests and teardowns were immediately 

useful in validating the information manufacturers provided. 

To compare data provided by manufacturers and the materials costs calculated by DOE’s 

subject matter experts,13 DOE discounted the calculated costs to reflect the higher volumes at 

which BC manufacturers typically operate. DOE scaled volume with the aid of a high-volume 

quote and simplification of the method described in section 5.5.3, which resulted in an 80­

13 DOE relied on two subject matter experts (SMEs), who are independent engineering contractors with extensive 

experience in the design of battery chargers and external power supplies, when conducting its analyses. 

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EERE-2008-BT-STD-0005 COMMENT 03
 

percent discount on all electronic components. Magnetic components were not discounted, as 

their price was already estimated based on high-volume commodity (i.e., steel and copper) 

prices. 

In subsequent calculations, the scaled, high-volume BOM costs were marked up to 

include additional production and non-production costs, as was done for data provided during 

manufacturer interviews (section 5.4. DOE then aggregated the MSP and efficiency data for each 

teardown unit with data provided by manufacturers to create average price-efficiency curves. 

These curves fed into subsequent analyses of the potential impacts of standards on consumers 

and the Nation. 

5.5.3 EPS Testing 

As with BC testing, DOE conducted EPS testing and teardowns to gain insight into the 

design of commercially available EPSs, which influenced the technology assessment presented 

in chapter 3. A further goal was the validation of cost-efficiency data obtained during 

manufacturer interviews. 

DOE performed EPS testing and teardowns for the determination analysis in two phases. 

Phase 1 consisted of two groups of EPSs whose nameplate output power ranged between 1 watt 

and 6 watts, and between 40 watts and 66 watts. Within these two ranges, DOE subjected EPSs 

with 5-watt and 60-watt output power to detailed teardowns to assess the cost-efficiency 

relationship at these two wattage ratings. DOE selected the 5-watt and 60-watt ratings due to 

their popularity, based on a review of eight EPS manufacturer catalogs14 and the advice of its 

subject matter experts. 

Table 5.15 lists some of the parameters of the 46 units purchased in phase 1. In the batch 

of units purchased, 12 units (26 percent) were ENERGY STAR/CEC Tier 1 compliant. 

14 DOE surveyed the websites of the following companies: Delta Electronics, Astec, FRIWO Group, Phihong, 

Leader Electronics, AcBel Polytech, FSP Group, and Dee Van Enterprises. 

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EERE-2008-BT-STD-0005 COMMENT 03
 

 

 

 

 

 

 

 

 

 

 

 

Table 5.15 Phase One Units Purchased and Their Characteristics 

Number 

of Units 

Output 

Power 

Output 

Voltage 

ENERGY 

STAR 

Number 

of Units 

Output 

Power 

Output 

Voltage 

ENERGY 

STAR 

1 

1 

1 

3 

2 

3 

2 

7 

1 

1 

1 

1 

1 

1 

1 

1 

1.125 

2.4 

2.5 

3 

3.6 

4.8 

5 

5 

5.15 

5.2 

6 

40 

40 

40 

45 

45 

5 

6 

5 

5 

6 

6 

5 

5 

5.15 

5.2 

5 

24 

24 

48 

12 

18 

Yes 

Yes 

Yes 

Yes 

1 

1 

1 

1 

1 

1 

1 

2 

2 

1 

1 

2 

1 

1 

1 

48 

48 

50 

50 

50 

50 

55 

60 

60 

60 

60 

60 

65 

66 

66 

12 

24 

5 

12 

18 

24 

19 

12 

12 

18 

20 

24 

24 

15 

18 

Yes 

Yes 

Yes 

Yes 

Yes 

46 total - - -

Following the development of the EPS product classes described in chapter 3, DOE 

purchased additional EPSs, many selected to have the same power or almost the same power as 

the representative units. To further isolate the effect of efficiency on cost, DOE strove to 

purchase multiple units by the same manufacturer. Additional EPSs by the same manufacturer 

were purchased, with output powers either higher or lower than the representative unit, to 

determine how the cost and efficiency scales with power within a product class, to validate the 

product-class boundaries defined in chapter 3, and to asses the variability of EPSs design within 

each product class. 

Figure 5.13, Figure 5.14, and Figure 5.15 present diagrams of EPSs purchased in phase 2, 

with efficiency on the y-axis and output power on the x-axis. To promote comparisons within and 

among different output power ranges, the EPSs were purchased such that a plot of their output 

power and efficiency would form an “inverted letter T.” The leg of each inverted T in the 

figures helped determine the cost-efficiency relationship, while the arms allowed DOE to 

validate product class divisions and improve its understanding of scaling. EPSs contributing 

additional points in the figures were purchased to enable additional comparisons. 

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EERE-2008-BT-STD-0005 COMMENT 03
Increasing 

Efficiency 

1.75 W 2.5 W 

2.6 W 3 W 

2.5 W 

2.75 W 

4 W 

Legend: 

Phihong 

Other 

0.5 W 1.7 W 2.5 W 3 W 4 W

Nameplate Output Power 

Figure 5.13 Illustration of Units in Product Class A Selected for Phase 2 Testing and 

Teardowns 

Increasing Legend: Efficiency Elpac 

SL Power 

18 W 

12 W 18 W 

10.2 W 18 W 30W 60 W 

10 W 18 W 50 W

Nameplate Output Power 

Figure 5.14 Illustration of Units in Product Class B Selected for Phase 2 Testing and 

Teardowns 

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EERE-2008-BT-STD-0005 COMMENT 03
Increasing 

Efficiency 

120 W 

100 W 

96 W 120 W 

100 W 

66 W 120 W 150 W 

Legend: 

Elpac XP Power 

SL Power Other 

Nameplate Output Power 

Figure 5.15 Illustration of Units in Product Class F Selected for Phase 2 Testing and 

Teardowns 

5.5.4 EPS Teardown Methodology 

DOE tore down a subset of the previously tested EPS units to identify design 

characteristics that can be used to improve EPS efficiency and to determine their associated 

costs. The end result of each teardown was a bill of materials, which included the electronic 

components of the EPS. This BOM was the only component of costs directly evaluated by DOE 

during the teardown portion of the EPS determination analysis. DOE estimated electronics BOM 

costs using the same method as for BCs (section 5.5.2). This included a master list of commonly 

available components, combined with catalog lookups and price estimates of similar parts when 

a given part was unavailable. 

While the online distributor catalogs provide a consistent set of prices at low volumes, 

most EPS are manufactured in very large volumes. Thus, DOE developed a second cost estimate 

assuming large-volume orders of 100,000 to 1,000,000 pieces. To develop the high-volume 

estimate, a separate volume discount was applied to each component category in the BOM (e.g., 

resistors, capacitors, semiconductors, magnetic parts). DOE developed these volume discounts 

by obtaining a high-volume quote for a power converter BOM and comparing the high-volume 

costs, from the quote, with low-volume costs obtained from distributor catalogs. The results of 

this comparison were then averaged by component category. DOE used the averages to scale the 

low-volume BOM costs of components in each category. 

5.5.5 EPS Teardown Results 

Using the above scaled BOM costs, DOE developed cost-efficiency plots for 5-watt and 

60-watt power supplies. Table 5.16 summarizes the 5-watt units DOE evaluated, which all had 

the same output voltage. The 60-watt EPSs were analyzed at four different output voltages: 

12 volts, 18 volts, 20 volts, and 24 volts. Because active mode efficiency depends on voltage, the 

12-volt units would have a different efficiency than the 24 volt units, even given the same 

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EERE-2008-BT-STD-0005 COMMENT 03
energy-efficient design and components. Therefore, only the results for the 60-watt, 12-volt unit 

were analyzed. 

Table 5.16 Phase One Units Torn Down 

Maximum Rated 

Output Power (W) Rated Voltage (V) 

Number of 

Units Analyzed 

5 

60 

60 

60 

60 

5 

12 

18 

20 

24 

9 

4 

1 

1 

2 

Figure 5.16 presents the cost versus active mode average efficiency plot for the 5-watt 

EPS units. The costs are shown for the two component cost estimates—high and low—calculated 

using the low-volume catalog lookup and the high-volume quote, respectively. 

$0.00 

$1.00 

$2.00 

$3.00 

$4.00 

$5.00 

$6.00 

BOM Cost [USD]

Low Estimate 

High Estimate 

30% 40% 50% 60% 70% 80% 

Average Efficiency [%] 

Figure 5.16 BOM Cost versus Average Efficiency of 5-Watt Units 

Figure 5.16 shows that there was approximately a four-fold difference in BOM costs 

between the high estimate calculated using distributor catalogs alone and the low estimate 

calculated through the volume quote and discounting. Considering that the electronics BOM 

costs presented in the figure would be marked up to account for mechanical components and 

packaging, as well as production and non-production costs, to arrive at an MSP, the low cost 

estimate is more representative of typical EPS costs. 

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Figure 5.16 also shows that costs tended to increase significantly between 35-percent 

efficiency and 60-percent efficiency due to the necessary transition from line-frequency to 

switched-mode power supply (SMPS) technology. However, once the designs incorporated 

SMPS technology and surpassed 65 percent efficiency, there was no clear relationship between 

cost and efficiency. 

Figure 5.17 presents the BOM cost versus no-load energy consumption for the 5-watt 

EPS units. As was the case with active mode efficiency, there was a significant cost increase 

associated with lowering no-load power from approximately 1.5 watt to 0.5 watt, corresponding 

with the shift from line-frequency to switched-mode designs. Further reductions in no-load 

power seem to incur no additional cost. 

$0.00 

$1.00 

$2.00 

$3.00 

$4.00 

$5.00 

$6.00 

BOM Cost [USD] 

Low Estimate 

High Estimate 

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 

No-Load Power [W] 

Figure 5.17 BOM Cost vs. No-Load Power of 5-Watt Units 

Figure 5.18 presents the high-volume (i.e., low estimate) BOM costs versus average 

efficiency of 5-watt EPS units, but combines energy consumption in both active and no-load 

modes. The color and shape of the data points reflect the CSL (section 5.3.2) met by each unit. 

For example, green circles represent units exceeding the CEC Tier 2 standard for active mode 

efficiency and no-load power consumption. The figure shows that increases in average efficiency 

track reductions in no-load power for the 5-watt units analyzed, but the only significant change 

in price is the increase caused by the shift in technology from line-frequency to switch-mode 

designs. 

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2 

EERE-2008-BT-STD-0005 COMMENT 03
$1.50 

$1.25 

BOM Cost [USD] $1.00 

$0.75 

$0.50 

$0.25 

$0.00 

Baseline Line-Frequency 

Baseline Switch-Mode 

CEC 2 

> CEC 2 

Market Best 

30% 40% 50% 60% 70% 80% 

Average Efficiency [%] 

Figure 5.18 BOM Cost and Efficiency of 5-Watt EPS Units 

Figure 5.19 displays the same data in a different way, plotting the active mode efficiency 

of the 5-watt EPSs directly against the no-load power consumption. Because the CSLs are 

defined in terms of these two metrics, they are also portrayed in the figure as shaded rectangles, 

with the most efficient CSLs grouped in the lower right of the figure. The shape and color of the 

data points indicate the low estimate of the BOM cost. Once an EPS uses switch-mode 

technology, there are no discernable incremental costs associated with meeting levels just 

beyond CEC 2. 

Baseline Switch-Mode 

CEC 1 & 2 

> CEC 

0 

0.25 

0.5 

0.75 

1 

1.25 

1.5 

1.75 

2 

No-Load Power [W]

< $0.50 

$0.50–0.75 

$0.75–1.00 

$1.00–1.25 

> $1.25 

30% 40% 50% 60% 70% 80% 

Average Efficiency [%] 

Figure 5.19 Average Efficiency and No-Load Power Consumption of 5-Watt EPSs with 

BOM Costs; Increasingly Stringent CSLs Are Represented by Darker Shades of Blue 

As with its analysis of the 5-watt units, DOE tore down 60-watt, 12-volt EPSs and 

estimated high and low BOM costs using the same methodology that included the master price 

lists and volume discounting using the high-volume quote. Figure 5.20 presents the cost versus 

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EERE-2008-BT-STD-0005 COMMENT 03
active mode average efficiency for the 60-watt EPS units. Figure 5.20 shows there is no apparent 

increase in cost for efficiency points greater than 65 percent. Since all the 60-watt EPSs DOE 

tore down incorporated switch-mode designs, these findings are consistent with the cost 

relationship for switch-mode 5-watt units presented in Figure 5.16. The small sample size, 

however, made robust comparisons difficult. 

$0.00 

$2.00 

$4.00 

$6.00 

$8.00 

$10.00 

$12.00 

$14.00 

$16.00 

BOM Cost [USD] 

Low Estimate 

High Estimate 

77% 78% 79% 80% 81% 82% 83% 84% 85% 86% 87% 

Average Efficiency [%] 

Figure 5.20 BOM Cost vs. Average Efficiency of 60-Watt Units 

Figure 5.21 presents the BOM cost and no-load energy consumption for the 60-watt EPS 

units. The costs are shown again for the low and high price estimates. Figure 5.21 shows there 

was no significant relationship between cost and no-load power for the EPSs DOE analyzed. 

This is similar to the conclusion DOE reached for 5-watt switched-mode EPSs. 

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EERE-2008-BT-STD-0005 COMMENT 03
$0.00 

$2.00 

$4.00 

$6.00 

$8.00 

$10.00 

$12.00 

$14.00 

$16.00 

BOM Cost [USD] 

Low Estimate 

High Estimate 

0 0.5 1 1.5 2 2.5 

No-Load Power [W] 

Figure 5.21 BOM Cost versus No-Load Power of 60-Watt Units 

Figure 5.22 presents the high-volume BOM costs and active mode efficiency of 60-watt 

EPS units. The color and shape of the data points provide a measure of the no-load mode 

efficiency for each unit. For example, the yellow triangles represent 60-watt, 12-volt EPSs that 

meet the CEC Tier 2 standard for active mode efficiency and no-load power consumption. The 

figure seems to show that increases in average efficiency tended to track reductions in no-load 

power in the sample of torn-down units, and that efficiency appeared to increase without a 

corresponding increase in cost. 

$4.00 

$3.50 

BOM Cost [USD]$3.00 

$2.50 

$2.00 

$1.50 

$1.00 

$0.50 

$0.00 

Baseline Switch-Mode 

CEC 2 

> CEC 2 

Market Best 

75% 77% 79% 81% 83% 85% 87% 89% 

Average Efficiency [%] 

Figure 5.22 BOM Cost and Efficiency of 60-Watt EPS Units 

Figure 5.23 rearranges the same data, presenting active mode efficiency and no-load 

power. Units in the lower-right corner meet the highest CSLs of efficiency, in terms of both 

active mode efficiency and no-load power. The shape and color of the data points indicate the 

calculated BOM costs. 

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Baseline Switch-Mode 

CEC 1 

> CEC 2 

CEC 2 

0 

0.5 

1 

1.5 

2 

2.5 

No-Load Power [W] 

< $3.00 

> $3.00 

76% 78% 80% 82% 84% 86% 88% 

Average Efficiency [%] 

Figure 5.23 Average Efficiency and No-Load Power Consumption of 60-Watt EPSs with 

BOM Costs; the Increasing CSLs Are Represented by Darker Shades of Blue 

5.6 Conclusion 

DOE did not finish the validation component of the engineering analysis, which consisted 

of testing and teardowns, before the rescheduling of the determination analysis in December 

2007. As a result, additional teardowns of BCs and EPSs, necessary to address some of the issues 

raised above, remained unfinished. Despite its incompleteness, the above description provides 

examples of the methods that DOE had planned to use to arrive at cost-efficiency estimates, such 

as output power and voltage scaling, as well as volume discounts and manufacturer markups. 

These results would have been incorporated into the life-cycle cost and payback period analyses 

and the national impact assessment described in the following chapters. 

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EERE-2008-BT-STD-0005 COMMENT 03
APPENDIX 5.A Battery Charger Cost-Efficiency Estimation Survey 

Navigant Consulting, Inc. (NCI) is conducting an engineering analysis to understand the relationship be

cost and the energy efficiency of Battery Chargers. This engineering analysis is part of a larger determination an

U.S. Department of Energy should conduct an energy conservation standards rulemaking on battery chargersupplies (BC-EPSs). Through this survey, NCI is seeking your guidance on design improvements you might ma

to improve their efficiency. All information you provide is covered by the Non-Disclosure Agreement be

company. NCI is focusing the engineering analysis on four types of battery chargers with differing charge rates, operating vcapacities, and consumer product applications. NCI believes each of these units is representative of other comm

product chargers. These four battery chargers are: 

• C/10, 1.2 V, 1.2 Ah, representing chargers for infrequently used personal care products, such as electric • C/10, 4.8 V, 1.2 Ah, representing chargers for cradle devices that typically remain in the charging cra

vacuums and kitchen appliances; 

• C/8, 18 V, 1.5 Ah, representing chargers for do-it-yourself (DIY) power tools that are used sporadically; • 1 C, 18 V, 2.5 Ah, representing chargers for professional power tools that are used frequently. 

For each of the above chargers, please use the tables on the following pages to describe the changes in factory coselling price associated with redesigning a baseline unit to achieve higher energy-efficiency levels. The efficienc

as: 

0. The industry-average energy consumption for typical chargers manufactured today (i.e., the “baseline” ch

1a. The energy consumption of infrequently-used and some cradle chargers with a wall adapter that meets CE

for external power supplies, adopted in January 2007. 

1b. The energy consumption of chargers without a wall adapter (i.e., some cradle, DIY-tool, and pro-tool cha

voluntary ENERGY STAR battery-charger standard. 

2. The lowest energy consumption achieved by comparable battery chargers in the market today. 3. The lowest energy consumption feasible, regardless of price (e.g., by using premium components, redesig

using exotic materials, etc.). 

In the data tables that follow, the energy consumption target at each efficiency level is based on the results of testhe Department of Energy, the Environmental Protection Agency, and the California Energy Commission, as welIn each case, the energy-efficiency of a charger is evaluated in terms of its maintenancemode power and No-Batt

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EERE-2008-BT-STD-0005 COMMENT 03
former is defined as the power consumed by the charger to maintain a fully-charged battery, while the latter is th

the charger once the battery or appliance has been disconnected from the charger. In addition to providing the manufacturer’s selling price of a unit that meets a given efficiency level, please also improvements that would be necessary to attain that level, as well as the resultant active mode efficiency exclusi

Also, please estimate the incremental change in production cost over the baseline for each design improvement. 

itemize the cost changes, please specify the total factory bill-of-materials (BOM) cost increase for all the improvWe would also welcome your input on the current distribution of battery chargers in each category by efficiency 

typical lifetime of the consumer products that use those chargers. We recognize that detailed designs would be burdensome to prepare; therefore, in the interests of generating reasshort amount of time, we invite you to use your best judgment and experience when completing the following tabPlease use the following design specifications for all chargers (or please indicate to us if one or more of these nee

Input voltage: 115 volts rms, 60 Hz Input protection: Primary current fuse Unit volume: 500,000 units/year Packaging: Sealed plastic Cord length: 6 feet Regulatory compliance: UL, FCC Product lifetime: > 2 years 

Thank you for your input. If you have any questions or suggestions, please contact: 

Matt Malinowski Michael Vladimer 202-481-7304 202-481-7323 Matt.Malinowski@NavigantConsulting.com MVladimer@NavigantConsulting.com 

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EERE-2008-BT-STD-0005 COMMENT 03
Example: Infrequently-Used Charger; C/10, 1.2 V, 1.2 Ah; 

The table on this page provides an example of the kind of information we are seeking to create an engineering-an

curve for battery chargers. In this particular example, we show one set of improvements for increasing the effici

a 1.2 V electric shaver to meet the requirements of the CEC Tier 1 external power supply standard. This exampl

and should not be interpreted as the only path to making a CEC-compliant shaver adapter. However, this table dindication of the level of detail being requested for the following tables. The column labeled “Incremental ChanCost” represents the cost of the specific improvement described. If additional rows are needed to describe all the improvements you would make, please feel free to modify the tables. The column labeled “Total Mfr. Unit Selliselling price to your customers, such as retail chains or other manufacturers (for bundling with a consumer produ

# 

Efficiency Level 

Maint.­

Mode 

Power 

[W] 

NoBattery 

Power 

[W] 

Active-Mode 

Conversion 

Efficiency 

[%] 

Defining Design 

Characteristics 

Mfr. 

Production 

Cost 

[$] 

Total M

Unit Sell

Price 

[$] 

0 

Baseline: Lowestcost Battery 

Charging System 

0.80 W 0.60 W 30 % 

60-Hz linear power supply $0.69 $1.50 

Rectifier diode $0.01 1.2 Ah NiMH cell $0.30 

# 

Efficiency Level 

Maint.­

Mode 

Power 

[W] 

NoBattery 

Power 

[W] 

Active-Mode 

Conversion 

Efficiency 

[%] 

Defining Design 

Characteristics 

Incremental 

Change in 

Mfr. 

Production 

Cost 

[+/- $] 

Total M

Unit Sell

Price 

[$] 

1a 

Charger Wall 

Adapter Meets 

CEC Tier 1 

0.70 W 0.50 W 60 % 

Improved core steel + $0.20 

Schottky diodes + $0.10 $1.95 

5-46

EERE-2008-BT-STD-0005 COMMENT 03
BC 1: Infrequently Used Charger; C/10, 1.2 V, 1.2 Ah; 

# 

Efficiency 

Level 

Maint. 

-Mode 

Power 

[W] 

NoBattery 

Power 

[W] 

Active-Mode 

Conversion 

Efficiency 

[%] 

Defining Design 

Characteristics 

Mfr. 

Production 

Cost 

[$] 

Total M

Unit Sell

Price 

[$] 

Baseline: 

0 

Lowest-cost 

Battery 

Charging 

System 

0.80 W 0.60 W 

# 

Efficiency 

Level 

Maint. 

-Mode 

Power 

[W] 

NoBattery 

Power 

[W] 

Active-Mode 

Conversion 

Efficiency 

[%] 

Defining Design 

Characteristics 

Incremental 

Change in 

Mfr. 

Production 

Cost 

[+/- $] 

Total M

Unit Sell

Price 

[$] 

1a 

Charger with 

Wall Adapter 

that Meets 

CEC Tier 1 

0.70 W 0.50 W 

2 Best in Market 0.35 W 0.04 W 

3 

Maximum 

Technologically 

Feasible 

0.10 W 0.01 W 

5-47

EERE-2008-BT-STD-0005 COMMENT 03
BC 2: Cradle Charger; C/10, 4.8 V, 1.2 Ah; 

# 

Efficiency Level 

Mainte 

nance 

Mode 

Power 

[W] 

NoBattery 

Power 

[W] 

Active-Mode 

Conversion 

Efficiency 

[%] 

Defining Design 

Characteristics 

Mfr. 

Production 

Cost 

[$] 

Total M

Unit Sell

Price 

[$] 

Baseline: 

0 Lowest-cost Battery Charging 

System 

1.9 W 0.6 W 

# 

Efficiency Level 

Mainte 

nance 

Mode 

Power 

[W] 

NoBattery 

Power 

[W] 

Active-Mode 

Conversion 

Efficiency 

[%] 

Defining Design 

Characteristics 

Incremental 

Change in 

Mfr. 

Production 

Cost 

[+/- $] 

Total M

Unit Sell

Price 

[$] 

1a 

Charger with 

Wall Adapter 

that Meets 

CEC Tier 1 

1.7 W 0.5 W 

2 Best in Market 1.5 W 0.4 W 

3 

Maximum 

Technologically 

Feasible 

0.5 W 0.05 W 

5-48

EERE-2008-BT-STD-0005 COMMENT 03
BC 3: DIY Tool Charger; C/8 18 V, 1.5 Ah; 

# 

Efficiency 

Level 

Maint.­

Mode 

Power 

[W] 

NoBattery 

Power 

[W] 

Active-Mode 

Conversion 

Efficiency 

[%] 

Defining Design 

Characteristics 

Mfr. 

Production 

Cost 

[$] 

Total M

Unit Sell

Price 

[$] 

Baseline: 

0 

Lowest-cost 

Battery 

Charging 

System 

6 W 1.5 W 

# 

Efficiency 

Level 

Maint.­

Mode 

Power 

[W] 

NoBattery 

Power 

[W] 

Active-Mode 

Conversion 

Efficiency 

[%] 

Defining Design 

Characteristics 

Incremental 

Change in 

Mfr. 

Production 

Cost 

[+/- $] 

Total M

Unit Sell

Price 

[$] 

1b 

Charger Meets 

ENERGY 

STAR 

Requirements 

1.5 W 0.8 W 

2 Best in Market 1 W 0.3 W 

3 

Maximum 

Technologically 

Feasible 

0.3 W 0.1 W 

5-49

EERE-2008-BT-STD-0005 COMMENT 03
BC 4: Pro Tool Charger; 1 C, 18 V, 2.5 Ah; 

# 

Efficiency 

Level 

Maint.­

Mode 

Power 

[W] 

NoBattery 

Power 

[W] 

Active-Mode 

Conversion 

Efficiency 

[%] 

Defining Design 

Characteristics 

Mfr. 

Production 

Cost 

[$] 

Total M

Unit Sell

Price 

[$] 

Baseline: 

0 

Lowest-cost 

Battery 

Charging 

4.7 W 2.1 W 

System 

# 

Efficiency 

Level 

Maint.­

Mode 

Power 

[W] 

NoBattery 

Power 

[W] 

Active-Mode 

Conversion 

Efficiency 

[%] 

Defining Design 

Characteristics 

Incremental 

Change in 

Mfr. 

Production 

Cost 

[+/- $] 

Total M

Unit Sell

Price 

[$] 

1b 

Charger Meets 

ENERGY 

STAR 

Requirements 

4.0 W 1.8 W 

2 Best in Market 3.0 W 1.0 W 3 

Maximum 

Technologically 

Feasible 1.2 W 0.1 W 

5-50

EERE-2008-BT-STD-0005 COMMENT 03
 

APPENDIX 5.B EPS Cost-Efficiency Estimation Survey 

Navigant Consulting, Inc. (NCI) is conducting an engineering analysis to understand the 

relationship between manufacturers’ cost and the efficiency15 of EPSs. This engineering analysis 

is part of a larger determination analysis on whether the U.S. Department of Energy should 

conduct an energy conservation standards rulemaking on battery chargers and external power 

supplies (BC-EPSs). Through this worksheet, NCI is seeking your guidance on design changes 

you might make to external power supplies to improve their efficiency. All information you 

provide is covered by the Non-Disclosure Agreement between NCI and your company. 

NCI is focusing its analysis on three switch-mode power supplies (SMPSs) with output powers of 

75 W, 12 W and 2.75 W. NCI believes each of these units represents similar SMPSs. In 

particular: 

•	 The 75 W, 12 V SMPS represents higher-power models that require power-factor 

correction (PFC) and therefore typically employ a two-stage forward topology; 

•	 The 12 W, 12 V SMPS represents general-purpose models with a single-stage flyback 

topology and PWM controller IC; and 

•	 The 2.75 W, 5 V SMPS represents lower-power models that typically employ a singlestage ring-choke converter topology, foregoing a PWM controller IC to save costs. 

For each of the supplies, please describe the discrete design steps you would undertake to 

achieve the efficiency level and no-load power specification shown in the table. In each case, 

start with a baseline SMPS, and list the necessary design changes to enable it to meet the higher 

efficiency levels. The efficiency levels are defined to be: 

0.	 The industry-average efficiency level, circa 2005, prior to the adoption of ENERGY 

STAR and California Energy Commission (CEC) Tier I, efficiency standards 

1.	 The level specified by the (voluntary) EPA ENERGY STAR program in 2006 and 

(mandatory) CEC Tier I standard in 2007 

2.	 The Tier II level adopted by the CEC, which will become the (mandatory) CEC standard 

on July 1, 2008. 

3.	 The maximum efficiency level achieved by products in the market today. 

4.	 The maximum efficiency level feasible regardless of price, using premium components 

and exotic materials. 

For each design change, please also provide an estimate of your incremental production cost over 

the baseline, as well as the total unit selling price to an OEM or distributor. In case it is not 

possible to list the increase in cost per design change, please specify the total bill-of-materials 

(BOM) cost increase for all the improvements. Finally, please describe your markup structure to 

make it clear how increases in production costs impact the total per-unit manufacturer’s selling 

price. 

We recognize that detailed designs may be difficult to prepare; therefore, in the interests of 

generating reasonable results in a short space of time, we invite you to use your best judgment 

and experience when completing the following tables. 

15 “Efficiency” is used in this worksheet as a proxy for both conversion efficiency and no-load power. 

5-51
 

EERE-2008-BT-STD-0005 COMMENT 03
Please use the following design specifications for all three SMPSs (or please indicate to us if one 

or more of these are problematic): 

Input voltage: 115 volts rms, 60 Hz Unit volume: 1 million units 

Input protection: Primary current fuse, 

inrush current limiting Application: Information technology/ 

consumer electronics 

Output voltage 

regulation: ± 1% (excluding cord) Package: Sealed polycarbonate 

Output voltage ripple: 1% VP-P maximum Output cord 

length: 6 feet 

Transient response: 0.5 ms for 50% load 

change typical 

Regulatory 

compliance: 

UL, FCC, 

PFC for PIN > 75 W 

Output protection: Overcurrent protection, 

short-circuit protection Product lifetime: > 2 years 

Thank you for your input. If you have any questions or suggestions, please contact: 

Matt Malinowski Michael Vladimer 

202-481-7304 202-481-7323 

Matt.Malinowski@NavigantConsulting.com MVladimer@NavigantConsulting.com 

5-52
 

EERE-2008-BT-STD-0005 COMMENT 03
 

 

 

 

The table on this page provides an example of the kind of information we need in order to create 

a cost-efficiency curve for SMPSs. In this particular example, we show one set of improvements 

for increasing the efficiency of an 80%-efficient 75 W, 12 V SMPS to meet the requirements of 

the ENERGY STAR program. This example is purely illustrative, and should not be taken as the 

only pathway to make a 75 W ENERGY-STAR SMPS. However, this table does provide an 

indication of the level of detail being requested for the tables on pages 3 through 5. The column 

labeled “Incremental Unit Cost per Improvement” represents the cost of the specific 

improvement described. If additional rows are needed to describe all the design changes you 

would make, please feel free to modify the tables. The column labeled “Total Mfr. Unit Selling 

Price” is your final selling price to your customers, such as OEMs or distributors. 

# Efficiency 

Level 

End-of-Cord 

Conversion 

Efficiency 

Example: EPS 1: POUT = 75 W, VOUT = 12 V 

No-Load 

Power 

Defining Design 

Characteristics 

Mfr. 

Production 

Cost 

Total Mfr. 

Unit Selling 

Price 

0 

Baseline: 

lowest-cost 

SMPS 

74%16 1 W 

2-stage topology with 

PFC -

$8 

UC3844 PWM 

controller -

-

Output rectifier w/ 

Schottkies 

E-type transformer 

-

Size: 4 in x 2.5 in x 1.5 

in -

# Efficiency 

Level 

End-of-Cord 

Conversion 

Efficiency 

No-Load 

Power 

Improvements over 

Baseline to Meet 

Efficiency Level 

Incremental 

Cost (over 

Baseline) per 

Improvement 

Total Mfr. 

Unit Selling 

Price 

1 

Efficiency 

Level 

(ENERGY 

STAR, CEC 

Tier I) 

III 

84 % 0.75 W 

Variable-frequency 

PWM controller IC + $0.05 

$10 

Change in transformer 

due to higher IC 

switching frequency 

+ $0.20 

Additional filtering 

caps due to higher IC 

EMI 

+ $0.12 

Miscellaneous 

additional components 

(e.g., XXXXX) 

+ $0.10 

16 These are NCI’s straw-man estimates of efficiency values. We welcome your input on these values. 

5-53 

EERE-2008-BT-STD-0005 COMMENT 03
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

EPS 1: POUT = 90 W, VOUT = 12 V 

# Efficiency 

Level 

End-of-Cord 

Conversion 

Efficiency17 

NoLoad 

Power 

Defining Design 

Characteristics 

Mfr. 

Production 

Cost 

Total Mfr. 

Unit Selling 

Price 

Baseline: 

0 lowest-cost 

SMPS 

82%18 0.8 W4 

# Efficiency 

Level 

End-of-Cord 

Conversion 

Efficiency 

NoLoad 

Power 

Improvements over 

Baseline to Meet 

Efficiency Level 

Incremental 

Cost (over 

Baseline) per 

Improvement 

Total Mfr. 

Unit Selling 

Price 

1 

Efficiency 

Level 

(ENERGY 

STAR, CEC 

Tier I) 

III 

84% 0.75 W 

2 

Efficiency 

Level 

(CEC Tier II) 

IV 

85% 0.5 W 

3 

Maximum 

Commercially 

Achieved (U.S. 

EPA, 2007) 

88% 0.18 W 

4 

Maximum 

Technologically 

Feasible 

92%4

 0.1 W4 

•	 How do you apply markups to your production costs in order to arrive at an OEM 

and distributor selling price? 

17 Conversion efficiency, as defined by DOE, ENERGY STAR, and CEC test procedures, is the arithmetic mean of
 

efficiencies at 100%, 75%, 50%, and 25% of maximum rated output current. 

18 These are NCI’s straw-man estimates of efficiency values. We welcome your input on these values. 

5-54
 

EERE-2008-BT-STD-0005 COMMENT 03
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

EPS 2: POUT = 18 W, VOUT = 12 V 

# Efficiency 

Level 

End-of-Cord 

Conversion 

Efficiency19 

NoLoad 

Power 

Defining Design 

Characteristics 

Mfr. 

Production 

Cost 

Total Mfr. 

Unit Selling 

Price 

0 

Baseline: 

lowest-cost 

SMPS 

67%20 1.4 W6 

# Efficiency 

Level 

End-of-Cord 

Conversion 

Efficiency 

NoLoad 

Power 

Improvements 

over Baseline to 

Meet Efficiency 

Level 

Incremental 

Cost (over 

Baseline) per 

Improvement 

Total Mfr. 

Unit Selling 

Price 

1 

Efficiency 

Level 

(ENERGY 

STAR, CEC 

Tier I) 

III 

75% 0.5 W 

2 

Efficiency 

Level 

(CEC Tier II) 

IV 

76% 0.5 W 

3 

Maximum 

Commercially 

Achieved (U.S. 

EPA, 2007) 

85% 0.06 W 

4 

Maximum 

Technologically 

Feasible 

88%6

 0.04 W6 

•	 How do you apply markups to your production costs in order to arrive at an OEM 

and distributor selling price? 

19 Conversion efficiency, as defined by DOE, ENERGY STAR, and CEC test procedures, is the arithmetic mean of
 

efficiencies at 100%, 75%, 50%, and 25% of maximum rated output current. 

20 These are NCI’s straw-man estimates of efficiency values. We welcome your input on these values. 

5-55
 

EERE-2008-BT-STD-0005 COMMENT 03
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

EPS 3: POUT = 2.75 W, VOUT = 5 V 

# Efficiency 

Level 

End-of-Cord 

Conversion 

Efficiency21 

NoLoad 

Power 

Defining Design 

Characteristics 

Mfr. 

Production 

Cost 

Total Mfr. 

Unit Selling 

Price 

0 

Baseline: 

lowest-cost 

SMPS 

55%22 0.77 W8 

# Efficiency 

Level 

End-of-Cord 

Conversion 

Efficiency 

NoLoad 

Power 

Improvements 

over Baseline to 

Meet Efficiency 

Level 

Incremental 

Cost (over 

Baseline) per 

Improvement 

Total Mfr. 

Unit Selling 

Price 

1 

Efficiency 

Level 

(ENERGY 

STAR, CEC 

Tier I) 

III 

58% 0.5 W 

2 

Efficiency 

Level 

(CEC Tier II) 

IV 

59% 0.5 W 

3 

Maximum 

Commercially 

Achieved (U.S. 

EPA, 2007) 

72% 0.02 W 

4 

Maximum 

Technologically 

Feasible 

75%8

 0.01 W8 

21 Conversion efficiency, as defined by DOE, ENERGY STAR, and CEC test procedures, is the arithmetic mean of
 

efficiencies at 100%, 75%, 50%, and 25% of maximum rated output current. 

22 These are NCI’s straw-man estimates of efficiency values. We welcome your input on these values. 

5-56 

EERE-2008-BT-STD-0005 COMMENT 03
 

 

 

APPENDIX 5.C Example BC Teardown Analysis Report 

Cost Estimate - External Power Supplies 

BC #2 Rev. B 

Estimate conducted by: J. Wexler 

Date: 2Dec07 

EPS Testing Label Number: 2 

Maximum Rated Output Power [W]: 6.3 

Output Voltage [V] 15 

Regulation Type: switch mode 

Manufacturer: China-made for Philips 

Model Number 8000X 

Estimated part costs taken from: Mouser, Digi-Key 

Total number of parts: 54; 23 leaded, 31surface mount 

Estimated Total Cost [$] $2.529 

Cost per part breakdown breakdown: 

Part Type mount: 

Surface/ Lead 

Part Details Part 

count 

Cost/ 

part [$] 

Cost 

[$] 

Choke L Axial lead choke 3.9mH TDK in 

Mouser 

2 0.35 0.70 

Diode L FR07 5 0.05 0.25 

Capacitor L 10uF, 400V 1 0.23 

Capacitor L 1500pF ceramic 1 0.025 

Zener L 1/2W 4 0.025 0.10 

Resistor L 1/4W 2 0.012 0.024 

Diode L 1N4148 2 0.02 0.04 

Transistor L TO-92 STBV32 1 0.10 

Capacitor L 100uF 25V 1 0.10 

Capacitor L 0.47uF 50V 1 0.05 

Diode L HEF02 1 0.07 

Transformer L Flyback choke 1 0.40 

Choke L Ferrite bead wound as small 

common mode choke 

1 0.10 

Resistor S 0603 13 0.007 0.091 

Resistor S 1206 13 0.012 0.156 

Capacitor S 0603 3 0.014 0.042 

Transistor S SOT-23 1 0.03 

Zener S SOT-23 1 0.021 

5-57
 

EERE-2008-BT-STD-0005 COMMENT 03
 

CHAPTER 6 ENERGY USE AND END-USE LOAD CHARACTERIZATION 

6.1 Introduction.......................................................................................................... 6-2 

6.2 Battery Chargers .................................................................................................. 6-2 

6.2.1 Battery Charger Usage Profiles ...............................................................6-2 

6.2.2 Battery Charger Energy Consumption.....................................................6-4 

6.3 External Power Supplies...................................................................................... 6-6 

6.3.1 External Power Supply Usage Profiles....................................................6-6 

6.3.2 External Power Supply Energy Consumption ......................................... 6-8 

LIST OF FIGURES 

Figure 6.1. Weekly Usage Profiles for BC Applications................................................. 6-3 

Figure 6.2. Usage Profiles for EPS Applications.............................................................6-7 

LIST OF TABLES 

Table 6.1. Weekly Usage Profiles for BC Applications–Numeric Values......................6-4 

Table 6.2. Energy Consumption Characteristics by Representative Product Class and 

Efficiency Level ..............................................................................................6-5 

Table 6.3. Unit Energy Consumption by Representative Product Class and Efficiency 

Level (kilowatt hours per year (kWh/yr)......................................................... 6-6 

Table 6.4. Usage Profiles for EPS Applications.............................................................. 6-8 

Table 6.5 EPS Active Mode Conversion Efficiency and No-Load Input Power by 

Efficiency Level ............................................................................................6-10 

Table 6.6. Average EPS Nameplate Output Power by Applications............................. 6-11 

Table 6.7 External Power Supply Active Mode Capacity Factors ................................6-12 

Table 6.8 Unit Energy Consumption of EPSs in Representative Product Class A 

(kWh/yr) ........................................................................................................ 6-18 

Table 6.9 Unit Energy Consumption of EPSs in Representative Product Class B 

(kWh/yr) ........................................................................................................ 6-19 

Table 6.10 Unit Energy Consumption of EPSs in Representative Product Class F 

(kWh/yr) ........................................................................................................ 6-20 

6-1
 

EERE-2008-BT-STD-0005 COMMENT 03
6.1 Introduction 

For the determination analysis, the Department of Energy (DOE) calculated unit 

energy consumption (UEC) using a combination of the inputs described in the following 

sections. The UEC represented the weighted average energy consumption of a single unit 

within a representative product class, and allowed for the simplified calculation of 

aggregate savings when combined with shipments. As a simplification, DOE assumed 

that the power and energy requirements of external power supply (EPS) applications 

would not change during the analysis period. In this section, DOE describes the 

calculation of usage profiles and unit energy consumption for battery chargers and for 

external power supplies. 

6.2 Battery Chargers 

6.2.1 Battery Charger Usage Profiles 

For the determination analysis, DOE developed usage profiles for each of the four 

representative product classes of battery chargers (BCs) by considering how their 

associated applications are used. Given the lack of published data on the subject, DOE 

relied heavily on input from industry experts to determine how applications are used. 

DOE developed usage patterns for each BC application, as an expression of the 

total time (in hours) spent per week in active mode, maintenance mode, no-battery mode, 

and stowed/unplugged. To better capture energy consumption across all potential usage 

behaviors, active mode and a portion of maintenance mode were grouped into 24-hour 

charge cycles. A 24-hour charge cycle is composed of the time spent in active mode to 

charge the battery and the remaining hours, which are spent in maintenance mode. 

Therefore, the modified usage profiles were expressed as a combination of the number of 

24-hour charge cycles, additional time spent in maintenance mode, no-battery mode, and 

unplugged. Figure 6.1 and Table 6.1 detail the weekly usage profiles for each BC 

application. 

6-2
 

EERE-2008-BT-STD-0005 COMMENT 03
 

Charge Cycle Maintenance Mode No Battery Mode Unplugged Mode 

Personal Care Products 

Kitchen Products 

Floor Care Products 

Universal Battery Chargers 

Digital Cameras* 

Video Cameras* 

Power Tools (non-professional) 

Power Tools (professional) 

Application 

0 24 48 72 96 120 144 168 

Hours per Week 

Figure 6.1. Weekly Usage Profiles for BC Applications 

Source: DOE, based on input from the Power Tool Institute and the Association of Home Appliance 

Manufacturers. 

* Only those digital cameras and camcorders that have a separate charging base and a battery designed to 

be removed from the camera for charging were considered BC applications. 

6-3
 

EERE-2008-BT-STD-0005 COMMENT 03
 

Table 6.1. Weekly Usage Profiles for BC Applications–Numeric Values 

Representative 

Product Class 

Product 

Application 

Weekly Usage Profile 

Number of 

24-Hour 

Charge 

Cycles 

Maintenance 

Mode Hours 

No-Battery 

Mode 

Hours 

Unplugged 

Hours 

Class A (0 to ≤ 3 

V) 

Personal Care 

Products 1 72 6 66 

Class B (3 < to ≤

9 V) 

Kitchen Products 1 143 1 0 

Floor Care 

Products 1 143 1 0 

Universal Battery 

Chargers 1 72 36 36 

Digital Cameras* 1 48 72 24 

Video Cameras* 1 72 48 24 

All Applications 

(shipmentweighted avg.) 1 83 38 23 

Class C (> 9V, 

Slow Charge) 

Power Tools (nonprofessional) 3 72 24 0 

Class F (> 9V, 

Fast Charge) 

Power Tools 

(professional) 5 36 12 0 

Source: DOE, based on input from the Power Tool Institute and the Association of Home Appliance 

Manufacturers. 

* Only those digital cameras and camcorders that have a separate charging base and a battery designed to 

be removed from the camera for charging were considered BC applications. 

6.2.2 Battery Charger Energy Consumption 

For the determination, DOE expressed BC energy consumption as the sum of 

energy consumed during 24-hour charge cycles (UEC24hr), maintenance mode 

(UECMaintenance) and no-battery mode (UECNoBattery). DOE calculated energy consumption 

for each representative product class using the following formulas: 

UEC = (UEC24hr +UECMa int enance +UECNoBattery )*365 / 7 Eq. 6.1 

Where: 

UEC 24hr = E 24hr ×N24hr 

UEC = P *t Ma int enance Ma int enance Ma int enance 

UEC = P *t NoBattery NoBattery NoBattery 

and 

6-4
 

EERE-2008-BT-STD-0005 COMMENT 03
E24 represents the energy consumed from mains by the battery charging system during a 

24 hour charge cycle, less the energy capacity of the battery, expressed in watt-hours 

(Wh); 

N24 represents the total number of 24-hour charge cycles per week; 

PMaintenance represents the average input power consumption of the battery charging 

system while in maintenance mode, expressed in watts (W); 

tMaintenance represents the time spent per week in maintenance mode, expressed in hours 

per week; 

PNoBattery represents the average input power consumption of the battery charging system 

while in no-battery mode, expressed in watts; 

tNoBattery represents the time spent per week in no battery mode, expressed in hours per 

week; and 

365/7 represents the adjustment for converting weekly energy consumption to annual 

energy consumption. 

6.2.2.1 E24, PMaintenance, PNoBattery 

From the engineering analysis in chapter 5, DOE calculated 24-hour energy 

consumption, maintenance mode input power, and no-battery mode input power value 

pairs for each representative product class at each candidate standard level CSL. Table 

6.2 gives these values. 

Table 6.2. Energy Consumption Characteristics by Representative Product Class 

and Efficiency Level 

Representative 

Product Class 

Characteristic Efficiency Level 

CSL 0 CSL 1 CSL 2 CSL 3 CSL 4 

Class A (0 to ≤ 3 

V) 

E24 

(Wh) 

55.0 22.0 14.0 10.0 7.0 

PMaintenance 

(W) 

2.4 1.0 0.7 0.5 0.3 

PNoBattery 

(W) 

0.9 0.5 0.5 0.3 0.2 

Class B 

(3 < to ≤ 9 

Volts(V)) 

E24 

(Wh) 

60.0 48.0 45.0 40.0 20.0 

PMaintenance 

(W) 

2.0 1.8 1.7 0.9 0.7 

PNoBattery 

(W) 

0.7 0.5 0.4 0.3 0.2 

Class C 

(> 9V, Slow 

Charge) 

E24 

(Wh) 

150.0 90.0 43.0 40.0 25.0 

PMaintenance 

(W) 

9.4 3.8 2.4 1.7 1.0 

PNoBattery 

(W) 

1.0 1.1 1.3 0.6 0.3 

Class F 

(> 9V, Fast 

Charge) 

E24 

(Wh) 

140.0 135.0 110.0 93.0 58.0 

PMaintenance 

(W) 

14.2 5.0 4.2 2.7 1.7 

PNoBattery 

(W) 

6.0 5.5 1.5 1.2 0.5 

6-5
 

EERE-2008-BT-STD-0005 COMMENT 03
Based on these inputs, DOE calculated the following values for UEC for each 

representative product class and each CSL. 

Table 6.3. Unit Energy Consumption by Representative Product Class and 

Efficiency Level (kilowatt hours per year (kWh/yr) 

Representative Product Class 

Efficiency Level 

CSL 0 CSL 1 CSL 2 CSL 3 CSL 4 

Class A (0 to ≤ 3 V) 12.0 4.9 3.5 2.5 1.5 

Class B (3 to ≤ 9 V) 13.2 11.3 10.6 6.6 4.3 

Class C (> 9V, Slow Charge) 60.0 29.5 17.4 13.4 8.0 

Class F (> 9V, Fast Charge) 66.9 48.0 37.5 30.1 18.6 

6.3 External Power Supplies 

6.3.1 External Power Supply Usage Profiles 

For the determination analysis, DOE developed usage profiles for each of the 

three representative product classes of EPSs by considering how the associated 

applications are used. DOE developed usage patterns for each EPS application, as an 

expression of the total time (in hours) spent per week in active mode, no-load mode, and 

stowed/unplugged. 

Considerable information was available on usage of EPS powered applications. 

DOE used the following sources to develop usage profiles for EPS applications: 

Porter, Moorefield, Ostendorp. Final Field Research Report. October 2006. Ecos 

Consulting: Durango, CO. 

Rosen and Meier. Energy Use of Consumer Electronics at the End of the 20th 

Century. 2000. Lawrence Berkeley National Laboratory: Berkeley, CA. 

Roth, Ponoum, and Goldstein. US Residential Information Technology Energy 

Consumption in 2005 and 2010. May 2006. TIAX: Cambridge, MA 

TIAX LLC. Assessment of Analyses Performed for the California Energy Efficiency 

Regulations for Consumer Electronics Products. Prepared by TIAX for CEA. 2 

February 2006. TIAX LLC: Cambridge, MA. 

Figure 6.2 and Table 6.4 show the usage profiles DOE developed for EPS applications. 

6-6
 

EERE-2008-BT-STD-0005 COMMENT 03
Camcorders
 

Cordless Phones
 

Digital Cameras
 

Flat Panel Monitors
 

Flatbed Scanners
 

Ink-jet Computer Printers
 

LAN Equipment
 

Modems/fax Modems
 

Notebook Computers
 

Portable Audio Players
 

Portable Gaming Devices
 

Portable Video Players
 

Small LCD TVs
 

Telephone Answering Devices 

Wi-Fi Access Points 

Wireless telephones 

0% 20% 40% 60% 80% 100% 

Percent of Time 

Application 

Active No-Load Unplugged 

Figure 6.2. Usage Profiles for EPS Applications 

6-7
 

EERE-2008-BT-STD-0005 COMMENT 03
Table 6.4. Usage Profiles for EPS Applications 

Product Application 

Usage Profile 

Percent Time 

Spent in Active 

Mode 

Percent Time 

Spent in Noload Mode 

Percent Time 

Spent 

Unplugged 

Camcorders 10 10 80 

Cordless Phones 100 0 0 

Digital Cameras* 10 10 80 

Flat Panel Monitors 100 0 0 

Flatbed Scanners 100 0 0 

Ink-Jet Computer Printers 100 0 0 

LAN Equipment 100 0 0 

Modems/Fax Modems 100 0 0 

Notebook Computers 82 10 8 

Portable Audio Players 18 36 46 

Portable Gaming Devices 70 20 10 

Portable Video Players 80 20 0 

Small LCD TVs 100 0 0 

Telephone Answering 

Devices 100 0 0 

Wi-Fi Access Points 100 0 0 

Wireless telephones 42 50 8 

* Only those digital cameras and camcorders that used an EPS in combination with an integrated charger 

and battery designed to remain in the camera for charging were considered EPS applications. 

6.3.2 External Power Supply Energy Consumption 

EPS energy consumption is the sum of energy consumed in active mode 

(UECactive) and in no-load mode (UECNL). 

To calculate energy consumption for EPS, DOE first calculated UECs for each 

application, then calculated an average UEC for each representative product class based 

on shipment weighting in each representative product class. This is in contrast to BCs, for 

which DOE calculated UECs for each representative product class based on weighted 

average usage and consumption characteristics. . This was due primarily to the greater 

availability of data on the usage and energy consumption for EPS applications, as well as 

the fact that many applications spanned multiple representative product classes. In 

addition, DOE assumed the UEC of an EPS application to be a function of EPS 

nameplate output power and application usage, both of which vary considerably from 

application to application. 

6-8
 

EERE-2008-BT-STD-0005 COMMENT 03
 

DOE calculated energy consumption for a given application and efficiency level 

using the following formulas: 

UEC = UEC active +UEC NL Eq. 6.2

Where: 

(1−η ) active UEC = × P × D ×t active out active

ηactive 

UEC = P *t NL NL NL 

and 

ηactive represents the active mode conversion efficiency of the EPS, expressed as 

percentage; 

Pout represents the nameplate output power of the EPS, expressed in watts; 

D represents the capacity factor of the EPS, based on the application, expressed as 

percentage; 

tactive and tNL represents the active mode time and no-load mode time, based on the usage 

profile previously discussed in this section, expressed in hours per year; and 

PNL represents the no-load input power, expressed in watts. 

6-9
 

EERE-2008-BT-STD-0005 COMMENT 03
6.3.2.1 Active Mode Conversion Efficiency, No-Load Input Power 

From the engineering analysis in chapter 5, DOE calculated active mode 

conversion efficiencies and no-load input power value pairs for each CSL. Table 6.5, 

taken from chapter 5, Table 5.7 gives these values. 

Table 6.5 EPS Active Mode Conversion Efficiency and No-Load Input Power by 

Efficiency Level 

Efficiency Level 

CSL 

0 

CSL 

1 

CSL 

2 

CSL 

3 

CSL 

4 

CSL5 CSL 

6 

Representative 

Product Class 

A (0 to < 4 W) 

Active 

Mode 

Conversion 

Efficiency 

30% 55% 58% 59% 65% 72% 75% 

No-Load 

Input 

Power (W) 

2.00 0.80 0.50 0.50 0.40 0.30 0.20 

Representative 

Product Class 

B (4 ≤ to ≤ 60 

W) 

Active 

Mode 

Conversion 

Efficiency 

66% 71% 75% 76% 80% 85% 88% 

No-Load 

Input 

Power (W) 

2.00 1.50 0.75 0.50 0.40 0.20 0.15 

Representative 

Product Class 

F (>60 W) 

Active 

Mode 

Conversion 

Efficiency 

N/A* 78% 84% 85% 87% 89% 92% 

No-Load 

Input 

Power (W) 

N/A* 2.00 0.75 0.50 0.40 0.31 0.15 

*During the determination, DOE found that all EPSs from representative product class F were already 

switch mode, therefore no values were calculated for CSL 0. 

6.3.2.2 Nameplate Output Power 

Table 6.6 lists the average nameplate output power for each application as used in 

the determination. Where applications spanned two representative product classes, 

separate average nameplate output powers were estimated for each. DOE used data from 

the qualified product (QP) list for ENERGY STAR end-use products and matched these 

applications with their associated EPSs in the QP list for ENERGY STAR qualified 

EPSs.1,2 For each application, DOE calculated the average nameplate output power of 

the associated EPSs. These estimates were verified by examining the distribution of EPS 

shipments across output powers in a report produced for the California Energy 

6-10
 

EERE-2008-BT-STD-0005 COMMENT 03
Commission.3

 This report was also used to estimate the average nameplate output power 

for those applications not included in the ENERGY STAR product lists. 

Table 6.6. Average EPS Nameplate Output Power by Applications 

Average Nameplate Output Power (W) 

Application 

Representative 

Product Class A 

<4W 

Representative 

Product Class B 

4-60W 

Representative 

Product Class F 

>60W 

Camcorders - 8 -

Cordless Phones 2.75 5 -

Digital Cameras 2.75 8 -

Flat Panel Monitors - 40 70 

Flatbed Scanners - 20 -

Ink-Jet Computer Printers - 25 -

LAN Equipment - 12 -

Modems/Fax Modems - 20 70 

Notebook Computers - 60 90 

Portable Audio Players 2.75 6 -

Portable Gaming Devices - 8 -

Portable Video Players - 15 -

Small LCD TVs - 45 70 

Telephone Answering 

Devices 2.75 5 -

Wi-Fi Access Points - 10 -

Wireless Telephones & PDAs 2.75 5 -

6.3.2.3 External Power Supply Capacity Factor 

For the determination, DOE used capacity factors to account for the fact that 

nearly all EPS-powered applications draw only a fraction of the nameplate output power 

of their EPS at any given time. This is because by definition, active mode accounts for all 

the time an EPS is plugged into mains and attached to an application. Many applications 

have multiple energy-consuming states that may fall under active mode consumption. To 

account for the variety of energy consuming active mode states, and using the same 

sources as those used to develop overall usage profiles, DOE then subdivided active 

mode into four states, including a) high-power start-up or energy-intensive states, b) 

medium power normal mode states, c) lower power idle states while “on”, and, d) “off” 

states. To estimate capacity factor, DOE considered the output power (as a percentage of 

nameplate output power) and time spent in each state (as a percentage of active mode 

time). DOE then calculated capacity factor as the weighted average of all states. Table 

6.7 shows the values used in the determination analysis. Where DOE could not determine 

capacity factor due to lack of information on either output power or time spent in each 

state, it used a default of 50 percent for capacity factor. 

6-11
 

EERE-2008-BT-STD-0005 COMMENT 03
Table 6.7 External Power Supply Active Mode Capacity Factors 

Camcorders 

EPS Mode Application State 

Percent of 

Nameplate 

Output Power 

(A) 

Percent of 

Time 

(B) 

Product 

(A×B) 

(Percent) 

Active Mode 

Charging 80 25 20 

Battery Maintenance 18 75 13.5 

Total Time 100% Sum Product

 Capacity Factor 33.5% 

Cordless Phones 

EPS Mode Application State 

Percent of 

Nameplate 

Output Power 

(A) 

Percent of 

Time 

(B) 

Product 

(A×B) 

(Percent) 

Active Mode 

Charging Handset 80 60 48 

Transmitting 69 5 4.8 

Standby 58 35 20.3 

Total Time 100 Sum Product

 Capacity Factor 73.1% 

Digital Cameras 

EPS Mode Application State 

Percent of 

Nameplate 

Output Power 

(A) 

Percent of 

Time 

(B) 

Product 

(A×B) 

(Percent) 

Active Mode 

Charging 80 25 20 

Battery Maintenance 18 75 13.5 

Total Time 100 Sum Product

 Capacity Factor 33.5% 

6-12
 

EERE-2008-BT-STD-0005 COMMENT 03
Flat Panel Monitors 

EPS Mode Application State 

Percent of 

Nameplate 

Output Power 

(A) 

Percent of 

Time 

(B) 

Product 

(A×B) 

(Percent) 

Active Mode 

Active 80 26 20.8 

Sleep 5 1 0.1 

Off 3 73 2.2 

Total Time 100 Sum Product

 Capacity Factor 23.1% 

Flatbed Scanners 

EPS Mode Application State 

Percent of 

Nameplate 

Output Power 

(A) 

Percent of 

Time 

(B) 

Product 

(A×B) 

(Percent) 

Active Mode 

Active 80 1 0.8 

Sleep 37 71 26.3 

Off 13 28 3.6 

Total Time 100% Sum Product

 Capacity Factor 30.7% 

Ink-Jet Computer Printers 

EPS Mode Application State 

Percent of 

Nameplate 

Output Power 

(A) 

Percent of 

Time 

(B) 

Product 

(A×B) 

(Percent) 

Active Mode 

Printing 80 1 0.8 

Sleep 24 18 4.3 

Off 9 81 7.3 

Total Time 100 Sum Product

 Capacity Factor 12.4% 

6-13
 

EERE-2008-BT-STD-0005 COMMENT 03
LAN Equipment 

EPS Mode Application State 

Percent of 

Nameplate 

Output Power 

(A) 

Percent of 

Time 

(B) 

Product 

(A×B) 

(Percent) 

Active Mode Active 80 100 80 

Total Time 100 Sum Product

 Capacity Factor 80% 

Modems/Fax Modems 

EPS Mode Application State 

Percent of 

Nameplate 

Output Power 

(A) 

Percent of 

Time 

(B) 

Product 

(A×B) 

(Percent) 

Active Mode Active 80 100 80 

Total Time 100 Sum Product

 Capacity Factor 80% 

Notebook Computers 

EPS Mode Application State 

Percent of 

Nameplate 

Output Power 

(A) 

Percent of 

Time (B) 

Product 

(A×B) 

(Percent) 

Active Mode 

High Power 80 13 10.4 

Low Power 33 14 4.6 

Sleep 3 11 0.3 

Off 3 62 1.9 

Total Time 100 Sum Product

 Capacity Factor 17.2% 

Portable Audio Players 

EPS Mode Application State 

Percent of 

Nameplate 

Output Power 

(A) 

Percent of 

Time (B) 

Product 

(A×B) 

(Percent) 

Active Mode 

Active 80 4 3.2 

Sleep 59 7 4.1 

Off 34 89 30.3 

Total Time 100 Sum Product

 Capacity Factor 37.6% 

6-14
 

EERE-2008-BT-STD-0005 COMMENT 03
Portable Gaming Devices 

EPS Mode Application State 

Percent of 

Nameplate 

Output Power 

(A) 

Percent of 

Time 

(B) 

Product 

(A×B) 

(Percent) 

Active Mode 

Charging 80 50 40 

Battery Maintenance 20 50 10 

Total Time 100 Sum Product

 Capacity Factor 50% 

Portable Video Players 

EPS Mode Application State 

Percent of 

Nameplate 

Output Power 

(A) 

Percent of 

Time 

(B) 

Product 

(A×B) 

(Percent) 

Active Mode 

Charging 80 50 40 

Battery Maintenance 20 50 10 

Total Time 100 Sum Product

 Capacity Factor 50% 

Small LCD TVs 

EPS Mode Application State 

Percent of 

Nameplate 

Output Power 

(A) 

Percent of 

Time (B) 

Product 

(A×B) 

(Percent) 

Active Mode 

Active 80 17 13.6 

Off 3 83 2.5 

Total Time 100% Sum Product

 Capacity Factor 16.1% 

Telephone Answering Devices 

EPS Mode Application State 

Percent of 

Nameplate 

Output Power 

(A) 

Percent of 

Time (B) 

Product 

(A×B) 

(Percent) 

Active Mode 

Play/Record 80 1 0.8 

Standby 71 99 70.3 

Total Time 100% Sum Product

 Capacity Factor 71.1% 

6-15
 

EERE-2008-BT-STD-0005 COMMENT 03
Wi-Fi Access Points 

EPS Mode Application State 

Percent of 

Nameplate 

Output Power 

(A) 

Percent of 

Time (B) 

Product 

(A×B) 

(Percent) 

Active Mode Active 80 100 80 

Total Time 100 Sum Product

 Capacity Factor 80% 

Wireless Telephones 

EPS Mode Application State 

Percent of 

Nameplate 

Output Power 

(A) 

Percent of 

Time 

(B) 

Product 

(A×B) 

(Percent) 

Active Mode 

Charging Handset 80 20 16 

Transmitting 15 2 0.3 

Standby 6 78 4.7 

Total Time 100 Sum Product

 Capacity Factor 21% 

6.3.2.4 Calculating Unit Energy Consumption by Application and Efficiency Level 

Using the inputs and formula given above, DOE calculated a UEC for each combination 

of application, efficiency level, and representative product class. These values are given 

in 

6-16
 

EERE-2008-BT-STD-0005 COMMENT 03
Table 6.8, Table 6.9, and Table 6.10. Using shipment weighting within each 

representative product class, DOE then calculated UECs for each representative product 

class at each efficiency level. These values are shown in the last row of the tables. 

6-17
 

EERE-2008-BT-STD-0005 COMMENT 03
Table 6.8 Unit Energy Consumption of EPSs in Representative Product Class A 

(kWh/yr) 

Application 

Efficiency Level 

CSL 0 CSL 1 CSL 2 CSL 3 CSL 4 CSL 5 CSL 6 

Camcorders - - - - - - -

Cordless Phones 40.47 14.19 12.56 12.05 9.34 6.75 5.78 

Digital Cameras 3.61 1.35 1.01 0.99 0.78 0.57 0.44 

Flat Panel Monitors - - - - - - -

Flatbed Scanners - - - - - - -

Ink-Jet Computer Printers - - - - - - -

LAN Equipment - - - - - - -

Medical Devices 39.48 14.02 12.04 11.59 9.00 6.52 5.49 

Modems/Fax Modems - - - - - - -

Notebook Computers - - - - - - -

Portable Audio Players 10.05 3.84 2.74 2.69 2.13 1.57 1.17 

Portable Gaming Devices - - - - - - -

Portable Video Players - - - - - - -

Small LCD TVs - - - - - - -

Telephone Answering 

Devices 39.91 13.99 12.39 11.89 9.21 6.65 5.70 

Wi-Fi Access Points - - - - - - -

Wireless Telephones 13.72 5.24 3.73 3.67 2.90 2.14 1.58 

Representative Product 

Class A UEC 21.30 7.76 6.25 6.06 4.73 3.45 2.79 

6-18
 

EERE-2008-BT-STD-0005 COMMENT 03
Table 6.9 Unit Energy Consumption of EPSs in Representative Product Class B 

(kWh/yr) 

Application 

Efficiency Level 

CSL 0 CSL 1 CSL 2 CSL 3 CSL4 CSL 5 CSL 6 

Camcorders 3.56 2.75 1.83 1.54 1.23 0.79 0.61 

Cordless Phones 16.25 12.88 10.51 9.96 7.88 5.57 4.30 

Digital Cameras 2.94 2.26 1.43 1.17 0.93 0.58 0.45 

Flat Panel Monitors 41.52 32.92 26.86 25.45 20.15 14.22 10.99 

Flatbed Scanners 27.98 22.18 18.10 17.15 13.58 9.58 7.41 

Ink-Jet Computer Printers 14.67 11.63 9.49 8.99 7.12 5.02 3.88 

LAN Equipment 43.32 34.35 28.03 26.56 21.02 14.84 11.47 

Medical Devices 55.49 43.85 34.95 32.74 25.93 18.16 14.02 

Modems/Fax Modems 72.20 57.25 46.72 44.26 35.04 24.73 19.11 

Notebook Computers 39.50 31.24 25.08 23.58 18.67 13.10 10.12 

Portable Audio Players 8.11 6.16 3.53 2.68 2.14 1.25 0.95 

Portable Gaming Devices 16.14 12.65 9.49 8.62 6.83 4.68 3.61 

Portable Video Players 30.58 24.10 18.83 17.47 13.84 9.63 7.43 

Small LCD TVs 32.49 25.76 21.02 19.92 15.77 11.13 8.60 

Telephone Answering 

Devices 16.02 12.70 10.37 9.82 7.77 5.49 4.24 

Wi-Fi Access Points 36.10 28.62 23.36 22.13 17.52 12.37 9.56 

Wireless Telephones 10.75 8.15 4.57 3.41 2.72 1.56 1.18 

Representative Product 

Class B UEC 29.39 23.15 18.03 16.69 13.22 9.18 7.09 

6-19
 

EERE-2008-BT-STD-0005 COMMENT 03
 

Table 6.10 Unit Energy Consumption of EPSs in Representative Product Class F 

(kWh/yr) 

Application 

Efficiency Level 

CSL 0 CSL 1 CSL 2 CSL 3 CSL 4 CSL 5 CSL 6 

Camcorders - - - - - -

Cordless Phones - - - - - -

Digital Cameras - - - - - -

Flat Panel Monitors 39.78 26.86 24.89 21.07 17.43 12.26 

Flatbed Scanners - - - - - -

Ink-Jet Computer Printers - - - - - -

LAN Equipment - - - - - -

Medical Devices 114.19 76.07 70.13 59.34 49.05 34.39 

Modems/Fax Modems 138.36 93.44 86.57 73.30 60.63 42.66 

Notebook Computers 32.75 21.59 19.83 16.77 13.86 9.69 

Portable Audio Players - - - - - -

Portable Gaming Devices - - - - - -

Portable Video Players - - - - - -

Small LCD TVs 27.67 18.69 17.31 14.66 12.13 8.53 

Telephone Answering 

Devices - - - - - -

Wi-Fi Access Points - - - - - -

Wireless Telephones - - - - - -

Representative Product 

Class C UEC 40.63 27.04 24.92 21.09 17.43 12.21 

References 

1

 Environmental Protection Agency. Qualified Product (QP) List for ENERGY STAR 

End-Use Products. http://energystar.gov/ia/products/prod_lists/eup_prod_list.xls. Last 

Accessed December 17, 2007. 

2

 Environmental Protection Agency. Qualified Product (QP) List for ENERGY STAR AcDc Qualified External Power Supplies. 

http://www.energystar.gov/ia/products/prod_lists/eps_ac_dc_prod_list.pdf. Last accessed 

December 17, 2007.

3

 TIAX LLC. “Assessment of Analyses Performed for the California Energy Efficiency 

Regulations for Consumer Electronics Products.” February 2006. TIAX LLC: 

Cambridge, MA. 

6-20
 

EERE-2008-BT-STD-0005 COMMENT 03
CHAPTER 7.PRODUCT PRICE DETERMINATION 

7.1 Introduction...................................................................................................... 7-2 

7.2 Battery Charger Markups................................................................................. 7-3 

7.3 External Power Supply Markups ..................................................................... 7-4 

LIST OF FIGURES 

Figure 7.1. BC and EPS Product Distribution Networks................................................. 7-2 

LIST OF TABLES 

Table 7.1. Retailer Markups for Battery Chargers...........................................................7-3 

Table 7.2. BC Manufacturer-to-Consumer Markups....................................................... 7-4 

Table 7.3. OEM Markups for External Power Supplies .................................................. 7-4 

Table 7.4. Retailer Markups for External Power Supplies .............................................. 7-5 

Table 7.5. EPS Manufacturer-to-Consumer Markups ..................................................... 7-5 

7-1
 

EERE-2008-BT-STD-0005 COMMENT 03
7.1 Introduction 

The purpose of the product price determination is to assess the impacts of the 

relationship between efficiency and manufacturer selling price (MSP) on end users. 

Therefore, during the determination analysis, DOE developed a retail (consumer) price 

for each candidate standard level (CSL) used in the life-cycle cost (LCC) and pay back 

period (PBP) analyses and the national impact analysis. DOE used MSP estimates 

(chapter 5) and studied the distribution value chain for battery chargers (BCs) and 

external power supplies (EPSs) moving from manufacturer to end user. With that 

information, DOE calculated a manufacturer-to-retail markup to convert MSP estimates 

to retail price estimates. DOE also developed a sales tax estimate, which it applied to the 

retail price estimates to arrive at end-user product prices. 

Component Manufacturers 

BC Manufacturers 

Consumer Product Retailers 

Consumers 

OEMs 

Component Manufacturers 

EPS Manufacturers 

Consumer Product 

Retailers 

Consumers 

OEMs EPS 

Distributors 

Battery Charger Distribution External Power Supply Distribution 

Figure 7.1. BC and EPS Product Distribution Networks 

Figure 7.1 shows the distribution networks for BCs and EPSs discussed in chapter 

3. DOE estimated MSPs in its engineering analysis. To estimate OEM and retailer 

markups, DOE used publicly available data on the gross margins of major publicly traded 

manufacturers and retailers.1

 Gross margin represents that portion of revenues that are 

over and above the cost of goods sold. The cost of goods sold includes variable and fixed 

costs directly linked to the product, such as material and labor. DOE used the following 

formula to derive markups from gross margins: 

7-2
 

EERE-2008-BT-STD-0005 COMMENT 03
 

GrossM arg in 

Markup = 1+ Eq.7.1 1− GrossM arg in 

7.2 Battery Charger Markups 

Table 7.1 displays the retailers and their respective gross margins, which DOE 

used to estimate markups for the determination analysis. DOE chose these retailers 

because they represent significant distribution channels for BC-powered applications. For 

BCs, DOE did not derive separate original equipment manufacturer (OEM) markups, 

because it received information from manufacturers about the prices at which BCs are 

sold to retailers. 

Table 7.1. Retailer Markups for Battery Chargers 

Battery 

Voltage 

Dominant 

Applications 

Leading 

Retailers 

Gross Margin 

(%) Markup 

Representative Product Class A 

0 to ≤ 3 V Personal care 

products 

Wal-Mart 24.21 1.32 

Target 32.74 1.49 

CVS 22.83 1.30 

Walgreens 28.35 1.40 

Average Markup 1.37 

Representative Product Class B 

>3 to ≤ 9 V 

Universal 

battery 

chargers, 

digital cameras, 

kitchen and 

floor care 

appliances 

Wal-Mart 24.21 1.32 

Target 32.74 1.49 

Best Buy 23.99 1.31 

Sears 28.37 1.40 

Bed Bath & 

Beyond 42.47 1.74 

Average Markup 1.45 

Representative Product Classes C and F 

> 9 V Power tools Home Depot 32.65 1.48 

Lowe’s 34.76 1.53 

Average Markup 1.51 

Note: Gross margins current as of December 21, 2007. 

The sales tax represents state and local sales taxes and is a multiplicative factor 

that increases the end-user product price. DOE obtained information on state and local 

sales taxes from the Sales Tax Clearinghouse. The Clearinghouse was established in 

August 1999 to facilitate the calculation of sales and use taxes administered by the 

Nation's 7,000 taxing authorities at the State, county, and city levels.2 DOE used a 

national, population-weighted average sales tax of 6.9 percent in its determination 

analysis. 

7-3
 

EERE-2008-BT-STD-0005 COMMENT 03
Using the sales tax information and information on markups by OEMs and 

retailers, DOE calculated the total markup for representative BC product classes (Table 

7.2). 

Table 7.2. BC Manufacturer-to-Consumer Markups 

Battery Voltage 

0 to ≤ 3 V >3 to ≤ 9 V 

> 9 V 

Slow 

Charging 

>9 V 

Fast Charging 

Retailer Markup 1.37 1.45 1.51 1.51 

Sales Tax 1.069 1.069 1.069 1.069 

Total Markup 1.46 1.55 1.61 1.61 

Note: Total markup equals the product of the three markups. Multiplying the manufacturer selling price by 

the total markup yields the consumer purchase price. 

Take, for example, low-voltage BCs, whose battery voltage is less than or equal to 

3 volts. The manufacturer selling prices DOE used as inputs in its preliminary BC 

analysis represent the prices at which BCs are sold to retailers. DOE found that the 

principal retailers mark up products by 37 percent over their wholesale price, resulting in 

a markup of 1.37. The Sales Tax Clearinghouse reported a national average sales tax of 

6.9 percent or 1.069. Multiplying these markups gives a total markup of 46 percent or 

1.46 for low-voltage BCs. DOE used the same process to arrive at manufacturer-toconsumer markups for EPSs and other BCs. 

7.3 External Power Supply Markups 

Most EPSs are manufactured for an OEM and sold through a retailer to the 

consumer. DOE gathered gross margin data of major OEM manufacturers in each 

representative product class, in addition to gross margins for major retailers of those 

products (Table 7.3 and Table 7.4). Because the retail outlets for the dominant EPS 

product applications are similar, DOE used a single retailer markup for all EPSs. During 

work on its determination analysis, DOE did not adjust its gross margin figures to 

account for alternate distribution patterns for EPSs, such as direct sales from an OEM to a 

consumer. 

Table 7.3. OEM Markups for External Power Supplies 

Representative Product Classes A and B 

Nameplate 

Output Power 

Dominant 

Applications Leading OEMs 

Gross 

Margin 

(%) 

Markup 

0 to < 4 W and 

≥ 4 to ≤ 60 W 

Telecommunications 

equipment 

Nokia 32.73 1.49 

Motorola 27.22 1.37 

Average Markup 1.43 

7-4
 

EERE-2008-BT-STD-0005 COMMENT 03
 

Representative Product Class F 

Nameplate 

Output Power 

Dominant 

Applications Leading OEMs 

Gross 

Margin 

(%) 

Markup 

> 60 W Notebook computers 

Dell, Inc. 18.71 1.23 

Hewlett Packard 24.36 1.32 

Apple, Inc. 33.97 1.51 

Average Markup 1.37 

Table 7.4. Retailer Markups for External Power Supplies 

All Representative Product Classes 

Nameplate 

Output Power 

Dominant 

Applications 

Leading 

Retailers 

Gross 

Margin 

(%) 

Markup 

All EPSs Consumer 

electronics 

Best Buy 24.00 1.32 

Circuit City 22.50 1.29 

Wal-Mart 24.21 1.32 

Average Markup 1.31 

Using the sales tax information and information on markups by OEMs and 

retailers, DOE calculated the total markup for representative EPS product classes (Table 

7.5. 

Table 7.5. EPS Manufacturer-to-Consumer Markups 

Nameplate Output Power 

0 to < 4 W ≥ 4 to ≤ 60 W > 60 W 

OEM Markup 1.43 1.43 1.36 

Retailer Markup 1.31 1.31 1.31 

Sales Tax 1.069 1.069 1.069 

Total Markup 2.00 2.00 1.90 

Note: Total markup equals the product of the three markups. Multiplying the manufacturer selling price by 

the total markup yields the consumer purchase price. 

References 

1

 Yahoo! Finance. . . . http://finance.yahoo.com. . . . Last accessed December 21, 2007. 

2

 Further information on the Sales Tax Clearinghouse can be found at www.thestc.com. 

7-5
 

EERE-2008-BT-STD-0005 COMMENT 03
CHAPTER 8.LIFE-CYCLE COST AND PAYBACK PERIOD ANALYSES 

8.1 Introduction................................................................................................................... 8-2 

8.2 Overview of LCC and PBP Inputs................................................................................ 8-2 

8.3 Life-Cycle Cost Inputs.................................................................................................. 8-5
 

8.3.1 Total Installed Cost Inputs................................................................................... 8-6 

8.3.2 Operating Cost Inputs .......................................................................................... 8-8 

8.3.3 Electricity Prices ................................................................................................ 8-10 

8.3.4 Life-Cycle Cost Discount Rates......................................................................... 8-11 

8.3.5 BC and EPS Operational Lifetimes ................................................................... 8-12 

LIST OF FIGURES 

Figure 8.1. Flow Diagram of Inputs for the Determination of LCC and PBP............................. 8-4 

Figure 8.2. AEO 2007 Residential Electricity Price Trend Forecast......................................... 8-11 

LIST OF TABLES 

Table 8.1. Draft Inputs to the Life-Cycle Cost and Payback Period Analysis............................. 8-5 

Table 8.3. Sales Tax by Division and Large States ..................................................................... 8-8 

Table 8.5. Shares and Interest or Return Rates Used for Household Debt and Equity Types... 8-12 

Table 8.6. Average Lifetimes for Battery Charger Applications............................................... 8-13 

Table 8.7. Shipment-Weighted Average Lifetimes for Battery Chargers ................................. 8-13 

Table 8.8. Average Lifetimes for External Power Supply Applications ................................... 8-14 

Table 8.9. Shipment-Weighted Average Lifetimes for External Power Supplies ..................... 8-14 

8-1 

EERE-2008-BT-STD-0005 COMMENT 03
8.1 Introduction 

This chapter describes the methodology that the Department of Energy (DOE) used to 

analyze the economic impacts of possible energy efficiency standards on individual consumers. 

DOE performed this analysis for the determination analysis on the same representative units 

evaluated in the engineering analysis. The effect of standards on individual consumers includes a 

change in operating expense (usually decreased) and a change in purchase price (usually 

increased). This chapter describes the two metrics DOE used in the consumer analysis to 

determine the effect of potential standards on individual consumers: 

•	 Life-cycle cost (LCC) is the total consumer expense over the life of an appliance, 

including purchase price and operating costs (including energy expenditures). DOE 

discounts future operating costs to the time of purchase, and sums them over the lifetime 

of the equipment. 

•	 Payback period (PBP) measures the amount of time it takes customers to recover the 

assumed higher purchase price of more energy-efficient equipment through lower 

operating costs. It represents the number of years it would take the customer to recover 

the increased purchase price through decreased operating expenses. 

DOE analyzed the net effect on consumers by calculating the LCC and PBP using data 

from the engineering analysis, the energy-use and end-use load characterization, and the product 

price determination. 

8.2 Overview of LCC and PBP Inputs 

For the determination analysis, DOE categorized inputs to the LCC and PBP analysis as 

follows: (1) inputs for establishing the purchase price, otherwise known as the total installed 

cost, and (2) inputs for calculating the operating cost. 

The primary inputs for establishing the total installed cost are: 

•	 baseline manufacturer cost, or the costs incurred by the manufacturer to produce 

equipment meeting existing minimum efficiency standards; 

•	 standard-level manufacturer cost increases, or the change in manufacturer cost 

associated with producing equipment to meet a particular standard level; and 

•	 markups and sales tax, or the markups and sales tax associated with converting the 

manufacturer cost to a consumer equipment price (chapter 7). 

The primary inputs for calculating the operating cost are: 

•	 equipment energy consumption, the site energy use associated with operating the 

equipment; 

8-2 

EERE-2008-BT-STD-0005 COMMENT 03
 

 

•	 equipment efficiency, which dictates the equipment energy consumption associated with 

standard-level equipment (i.e., equipment with efficiencies greater than baseline 

equipment); 

•	 energy prices, the prices paid by consumers for energy (i.e., electricity), determined using 

current energy prices based on data from DOE‘s Energy Information Administration 

(EIA); 

•	 energy price trends , derived from the EIA Annual Energy Outlook 2007 (AEO2007) to 

forecast energy prices into the futurea; 

•	 lifetime, the age at which the equipment is retired from service; and 

•	 discount rate, the rate at which DOE discounted future expenditures to establish their 

present value. 

Figure 8.1 presents the flow diagram for the draft determination analysis LCC developed 

in 2007. The figure depicts, from left to right, LCC inputs in yellow boxes, interim calculated 

values in green boxes, and final output values (i.e., LCC and PBP) in blue boxes. Table 8.1. lists 

the draft inputs DOE developed in 2007 for the determination analysis. 

a

 For the results presented in this chapter, DOE used the AEO2007 reference case to forecast future energy prices. 

8-3 

EERE-2008-BT-STD-0005 COMMENT 03
Figure 8.1. Flow Diagram of Inputs for the Determination of LCC and PBP 

8-4 

EERE-2008-BT-STD-0005 COMMENT 03
 

Table 8.1. Draft Inputs to the Life-Cycle Cost and Payback Period Analysis 

Input Description Average or 

Typical Value 

Sources 

Product Price The retail price before tax (i.e., 

bundled with a consumer 

product). Based on a 

manufacturer selling price 

marked up through the 

distribution chain. 

Varies Distributor catalogs, highvolume price estimates, 

manufacturer interviews. 

Sales Tax Used to convert the product 

price to a final consumer 

purchase price including sales 

tax. 

6.9% Weighted average of sales tax 

in 13 geographic regions and 

large states. 

Unit Energy 

Consumption 

The annual on-site electricity 

consumption associated with a 

BC or EPS. 

Varies Developed in section 6, Energyuse and End-use Load 

Characterization. 

Electricity 

Prices 

The national residential sector 

average price per kilowatt-hour 

(i.e., $/kWh). 

$0.097/kWh in 

2005 

Energy Information 

Administration (EIA), discussed 

in section 8.3.3. 

Electricity 

Price Trends 

Projects changes in the price of 

electricity over the analysis 

period. Includes a high and low 

scenario. 

Varies The Annual Energy Outlook 

from the EIA. 

Product 

Lifetime 

The total years in use after 

which the consumer retires the 

BC or EPS from service. The 

BC or EPS may be retired 

before the end of its useful life 

if the consumer product it 

operates is retired from service. 

3 - 5 years Discussed in section 8.3.5. 

Discount Rate The rate DOE estimates to be 

representative of BC and EPS 

consumers, used to discount 

future expenditures and 

establish their present value. 

5.6% Weighted average of residential 

financing methods, discussed in 

section 8.3.4. 

Analysis 

Period 

The time period over which 

DOE calculates the LCC. 

Product lifetime Discussed in section 8.3.5. 

8.3 Life-Cycle Cost Inputs 

When calculating the LCC, DOE discounted future operating costs to the time of 

purchase and summed them over the lifetime of the equipment, as shown in Equation 1: 

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EERE-2008-BT-STD-0005 COMMENT 03
N OC LCC = IC +∑ t

t Eq.8-1 t=1 (1+ r)

where: 

LCC = life-cycle cost in dollars,
 

IC = total installed cost in dollars, 

∑ = sum over the lifetime, from year 1 to year N, 

N = lifetime of product in years, 

OC = operating cost in dollars, 

r = discount rate, and 

t = year for which operating cost is being determined. 

DOE conducted preliminary work on the LCC as part of its determination analysis 

directed by EPACT 2005. The text that follows discusses some of these inputs and 

methodologies that DOE was developing when the analysis was rescheduled. 

DOE developed an LCC methodology based on the approach followed in other 

rulemakings, but tailored it for some unique aspects of BCs and EPSs. For example, while the 

equation above mentions “total installed cost” in its list of LCC input variables, DOE considers 

these costs to be just the equipment price, because BCEPS 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. 

The following sections discuss total installed cost, operating cost, lifetime, and discount 

rate. 

8.3.1 Total Installed Cost Inputs 

DOE defines the total installed cost using the following equation: 

IC = EQP Eq.8-2 

where: 

IC= total installed cost, expressed in dollars, and 

EQP = equipment price (i.e., purchase price for the equipment 

only), expressed in dollars. 

The equipment price is based on how the consumer purchases the equipment. DOE 

defined markups and sales taxes for converting manufacturing costs into consumer equipment 

prices. For BCs and EPSs the cost of installation is zero; therefore, it is not included in the 

equation. 

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EERE-2008-BT-STD-0005 COMMENT 03
 

There are four inputs that determine total installed cost. 

• Baseline Manufacturer Cost 

• Standard-Level Manufacturer Cost 

• Markups 

• Sales Tax 

The baseline manufacturer cost is the cost incurred by the manufacturer to produce 

equipment meeting existing minimum efficiency standards. Standard-level manufacturer cost 

increases are the change in manufacturer cost associated with producing equipment at a standard 

level. Markups and sales tax convert the manufacturer cost to a consumer equipment price. Thus, 

the total installed cost accounts for all factors contributing to the consumer equipment price. 

DOE calculated the total installed cost for baseline products based on the following equation: 

ICBASE = EQPBASE Eq.8-3 = COSTMFG × MUOVERALL 

where: 

ICBASE = baseline total installed cost, 

EQPBASE = consumer equipment price for baseline models, 

COSTMFG = manufacturer cost for baseline models, and 

MUOVERALL = overall markup (product of manufacturer markup, retailer 

or distributor markup, and sales tax). 

DOE calculated the total installed cost for standard-level products based on the following 

equation: 

IC STD STD = EQP

= (EQPBASE + ∆EQPSTD ) Eq.8-4 

= (IC BASE + ∆COST MFG OVERALL )× MU

where: 

ICSTD = standard-level total installed cost, 

EQPSTD = consumer equipment price for standard-level models, 

EQPBASE = consumer equipment price for baseline models, 

∆EQPSTD = change in equipment price for standard-level models, 

ICBASE = baseline total installed cost, and 

∆COSTMFG = change in manufacturer cost for standard-level models. 

MUOVERALL = overall markup (product of manufacturer markup, retailer 

or distributor markup, and sales tax). 

8-7 

EERE-2008-BT-STD-0005 COMMENT 03
DOE researched information about each of the above input variables that it used to 

calculate the total installed cost for external power supplies and battery chargers. DOE developed 

its manufacturer prices through manufacturer interviews, testing and teardowns, and researching 

distributor catalogues (chapter 5). OEM, distributor, and retailer markups came from 

manufacturer interviews and a review of publicly available company financial filings. Sales tax 

was based on a weighted average in 13 geographic regions and large states (Table 8.2). 

Table 8.2. Sales Tax by Division and Large States 

State/Region Sales Tax 

(%) 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

New England 

Mid Atlantic 

East North Central 

West North Central 

South Atlantic 

East South Central 

West South Central 

Mountain 

Pacific 

New York State 

California 

Texas 

Florida 

4.8 

7.1 

15.5 

6.7 

13.0 

5.9 

3.6 

7.0 

4.0 

6.4 

12.2 

7.9 

6.0 

 U.S. Average 6.9 

8.3.2 Operating Cost Inputs 

DOE defines the operating cost by the following equation: 

OC = EC Eq.8-5 

where: 

OC = operating cost, expressed in dollars, and 

EC = energy expenditure associated with operating the 

equipment. 

Although operating costs typically encompass repair and maintenance costs, DOE 

considered those costs (which are usually associated with larger products and appliances) to be 

zero in the draft LCC for the determination analysis. In making this decision, DOE recognized 

the reality of the marketplace, where 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 did fail, DOE expects that 

consumers would typically discard the device and purchase a replacement BC or EPS. 

8-8 

EERE-2008-BT-STD-0005 COMMENT 03
__

The inputs for determining the operating costs are listed below. 

• Annual Energy Consumption 

• Energy Prices 

• Energy Trends 

• Product Lifetime 

• Discount Rate 

• Effective Date of Standard 

The annual energy consumption is the site energy use associated with operating the 

equipment. The annual energy consumption varies with the product efficiency. That is, the 

energy consumption associated with standard-level equipment (i.e., equipment with efficiencies 

greater than baseline equipment) is less than the consumptions associated with baseline 

equipment. Energy prices are the prices paid by consumers for energy (i.e., electricity). 

Multiplying the annual energy by the energy prices yields the annual energy cost. DOE used 

energy price trends to forecast energy prices into the future and, along with the product lifetime 

and discount rate, to establish the lifetime energy costs. The product lifetime is the age at which 

the equipment is retired from service. The discount rate is the rate at which DOE discounted 

future expenditures to establish their present value. DOE calculated the operating cost for 

baseline products based on the following equation: 

OC BASE BASE = EC

Eq.8-6 = AECBASE × PRICEENERGY 

where: 

OCBASE = baseline operating cost, 

ECBASE = energy expenditure associated with operating the baseline 

equipment, 

AECBASE = annual energy consumption for baseline equipment, and 

PRICEENERGY = energy price. 

DOE calculated the operating cost for standard-level products based on the following equation: 

OCSTD = ECSTD 

= AEC STD × PRICE ENERGY Eq.8.7

= (AEC BASE ∆AEC STD )× PRICEENERGY 

where: 

OCSTD = standard-level operating cost, 

ECSTD = energy expenditure associated with operating standardlevel equipment, 

AECSTD = annual energy consumption for standard-level equipment, 

8-9 

EERE-2008-BT-STD-0005 COMMENT 03
PRICEENERGY = energy price, 

∆AECSTD = change in annual energy consumption caused by standardlevel equipment, and 

AECBASE = annual energy consumption for baseline equipment. 

The following sections provide information about electricity prices, discount rate, and 

product lifetime that DOE used to calculate the operating costs for external power supplies and 

battery chargers. Annual energy consumption is discussed in chapter 6. 

8.3.3 Electricity Prices 

For residential consumers of BCs and EPSs, DOE used projections of national average 

electricity prices from EIA’s Annual Energy Outlook (AEO) for the most recent year available. 

In other rulemakings, DOE has calculated a regionally-weighted average electricity price, based 

on inventories of products developed through EIA’s Residential Energy Consumption Survey. 

This data allows the electricity price used in the LCC to be more accurate if products have 

different regional sales rates (i.e., heaters in colder regions). However, the survey did not include 

questions on inventories of BCs and EPSs; therefore, DOE was unable to create a national 

installed-base-weighted average electricity price. Instead, DOE used the national average 

electricity price, as published by EIA. 

To ascertain the sensitivity of the LCC to future electricity price trends as well as the 

reference case, DOE evaluated the LCC using both the low and high economic growth cases. 

Together, these three cases reflect the uncertainty in electricity prices over the analysis period. 

Figure 8.2 presents the residential electricity price trends (in constant 2007$), based on AEO 

2007 projections. 

8-10 

EERE-2008-BT-STD-0005 COMMENT 03
Cents/kWh (2007$)

10.8 

10.7 

10.6 

10.5 

10.4 

10.3 

10.2 

10.1 

10.0 

9.9 

High
 

Low
 

Ref 

9.8 

2006 2008 2010 2012 2014 2016 2018 2020 2022 

Figure 8.2. AEO 2007 Residential Electricity Price Trend Forecast 

8.3.4 Life-Cycle Cost Discount Rates 

Discounting reflects the current value of money spent or saved in the future. As 

discussed, calculating consumer LCC required DOE to use a discount rate to determine the 

present value of the money the consumer would spend to operate the BCs and EPSs over their 

lifetime. Because consumers can use a variety of financial means to purchase a BC or EPS, the 

discount rate should equal the average cost of capital to the consumer. DOE assumed these 

financial means, listed in Table 8.3, to be similar to the ones consumers use when purchasing and 

financing replacement appliances for the home. 

DOE adapted the LCC discount rate derived in the home appliances rulemaking to its 

draft analysis. DOE’s approach involved identifying all possible debt or asset classes that 

consumers might use to purchase replacement equipment, including household assets that might 

be affected indirectly. 

DOE estimated the shares of the various debt and equity classes in the typical U.S. 

household portfolio using the Federal Reserve’s Survey of Consumer Finances (SCF) data for 

1989, 1992, 1995, 1998, 2001, and 2004. DOE also used SCF data to determine rates of return 

for each class. DOE then calculated an average rate weighted by the share of each class of debt 

or equity, equal to 5.6 percent, to represent a household discount rate, shown in Table 8.3. 

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EERE-2008-BT-STD-0005 COMMENT 03
 

Table 8.3. Shares and Interest or Return Rates Used for Household Debt and Equity 

Types 

Type 

Average Share of 

Household Debt Plus 

Equity* (%) 

Mean Real 

Effective Discount 

Rate** (%) 

Home Equity Loans 3.6 

Credit Cards 2.0 

Other Installment Loans 1.7 

Other Residential Loans 4.9 

Other Line of Credit 0.5 

Checking Accounts 4.5 

Savings and Money Market Accounts 15.7 

Certificates of Deposit 9.0 

Savings Bonds 1.5 

Bonds 10.0 

Stocks 29.1 

Mutual Funds 17.5 

4.0 

11.0 

6.0 

4.6 

8.7 

0.0 

2.3 

2.4 

3.5 

4.2 

8.8 

7.0 

Total/Weighted-Average Discount 

Rate 

100 

* Not including primary mortgage or retirement accounts. 

** Adjusted for inflation and, for home equity loans, loan interest tax deduction. 

5.6 

8.3.5 BC and EPS Operational Lifetimes 

Lifetime data are important for determining life-cycle costs and payback periods. In the 

NIA, lifetime data allow for an estimate of the total stock of EPSs being used. Because BCs and 

EPSs are often made specifically for use with particular consumer products, their lifetimes relate 

directly to the lifetimes of those products. DOE assumed 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 group of BCs and EPSs, DOE gathered lifetime values for consumer product 

applications and combined them with shipment estimates to derive a shipment-weighted average 

lifetime representative of the group. Average lifetimes for BC and EPS applications are shown in 

Table 8.4 and Table 8.6. 

DOE estimated lifetimes for categories that include multiple applications by examining the 

lifetimes of popular applications within them. For example, DOE examined the lifetimes of 

shavers, beard trimmers, hand-held massagers, and heating pads and used their relative shipments 

to derive the lifetime of personal care products. With shipments data and these application 

lifetimes, DOE calculated the shipment-weighted average lifetime of each representative product 

class of BCs and EPSs. These values are shown in 1. Appliance Magazine. . 30th Annual Portrait of the 

U.S. Appliance Industry. . September 2007. 

2. 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: 

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EERE-2008-BT-STD-0005 COMMENT 03
 

Background Data on Battery Chargers and Power Supplies. Cited henceforth as DOE FY05 Rulemaking Appendix 

A9. 

Table 8.5 and Table 8.7. 

Table 8.4. Average Lifetimes for Battery Charger Applications 

Representative 

Product Class Application Lifetime (Years) Source 

A Personal Care Products 3 Appliance Magazine1 

Kitchen Products 6 Appliance Magazine1 

Floor Care Products 6 Appliance Magazine1 

Universal Battery Chargers 4 DOE estimate 

B Digital Cameras 6 DOE FY05 Rulemaking Appendix 

A92 

Camcorders 6 DOE FY05 Rulemaking Appendix 

A92 

C DIY Power Tools 5 DOE estimate 

F Pro Power Tools 5 DOE estimate 

1. Appliance Magazine. . 30th Annual Portrait of the U.S. Appliance Industry. . September 2007. 

2. 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. Cited henceforth as DOE FY05 Rulemaking Appendix 

A9. 

Table 8.5. Shipment-Weighted Average Lifetimes for Battery Chargers 

Battery Voltage 

0 to ≤ 3 V >3 to ≤ 9 V > 9 V Slow Charging >9 V Fast Charging 

Lifetime 3 years 5 years 5 years 5 years 

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EERE-2008-BT-STD-0005 COMMENT 03
 

Table 8.6. Average Lifetimes for External Power Supply Applications 

Application Lifetime 

(Years) 

Source 

Ink-Jet Computer Printers 5 DOE FY05 Rulemaking Appendix A9 

Notebook Computers 4 DOE FY05 Rulemaking Appendix A9 

Modems/Fax Modems 4 DOE FY05 Rulemaking Appendix A9 

LAN Equipment 4 DOE FY05 Rulemaking Appendix A9 

Wi-Fi Access Points 4 DOE FY05 Rulemaking Appendix A9 

Flat Panel Monitors 4 DOE FY05 Rulemaking Appendix A9 

Flatbed Scanners 4 Estimated based on average computer peripheral lifetime 

Portable Video Players 4 Estimated based on TV/VCR/DVD combined lifetime of 6 

years, adjusting for increased wear and tear 

Cordless Phones 6 DOE FY05 Rulemaking Appendix A9 

Wireless Telephones 2 DOE FY05 Rulemaking Appendix A9 

Telephone Answering 

Devices 6 DOE FY05 Rulemaking Appendix A9 

Digital Cameras 6 DOE FY05 Rulemaking Appendix A9 

Portable Gaming Devices 2 

Estimated based on fast turnover of gaming operating systems 

and software, as well as greater wear and tear relative to 

stationary gaming systems. 

Small LCD TVs 6 DOE FY05 Rulemaking Appendix A9 

Portable Audio Players 6 DOE estimate 

Camcorders 6 DOE FY05 Rulemaking Appendix A9 

Table 8.7. Shipment-Weighted Average Lifetimes for External Power Supplies 

Nameplate Output Power 

0 to < 4 W ≥ 4 to ≤ 60 W > 60 W 

Lifetime 4 years 5 years 4 years 

References 

1. Appliance Magazine. . 30th Annual Portrait of the U.S. Appliance Industry. . September 2007. 

2. U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy. . FY2005 

Preliminary Priority-Setting Summary Report and Actions Proposed. . Appendix A: FY2005 

Technical Support Document. . Table A9-1: Background Data on Battery Chargers and Power 

Supplies. . (Last accessed March 3, 2006.) 

www.eere.energy.gov/buildings/appliance_standards/pdfs/fy05_priority_setting_app_a.pdf. 

8-14 

EERE-2008-BT-STD-0005 COMMENT 03
 

CHAPTER 9. SHIPMENTS ANALYSIS 

9.1 Current Year Shipments................................................................................... 9-3 

9.1.1 Battery Charger Shipments...................................................................... 9-3 

9.1.2 External Power Supply Shipments........................................................... 9-4 

9.2 Base Case Shipments Forecasts....................................................................... 9-8 

9.2.1 Total Annual Shipments .......................................................................... 9-8 

9.2.2 Natural Progression of Efficiency Over Time ......................................... 9-9 

9.3 Standards Case Shipments Forecasts.............................................................9-12 

9.3.1 Impact of Standards on Total Annual Shipments.................................. 9-13 

9.3.2 Impact of Standards on Distribution of Shipments Across Efficiency 

Levels 9-13 

9.3.3 Adjusting Dynamic Progression Rates Following the Standard............9-14 

LIST OF FIGURES 

Figure 9.1. Progression in a Dynamic Market State ...................................................... 9-15 

LIST OF TABLES 

Table 9.1. Battery Charger Shipments by Representative Product Class in 2007...........9-3 

Table 9.2. Distribution of BC Shipments Across Efficiency Levels by Representative 

Table 9.4. Distribution of EPS Application Shipments Across Representative Product 

Table 9.5. External Power Supply Shipments by Representative Product Class in 20079-6 

Table 9.9. Final Distribution of Shipments by Efficiency for External Power Supplies.9-8 

Table 9.16. EPS Representative Product Class A, Dynamic Natural Progression, Base 

Table 9.17. EPS Representative Product Class A, Dynamic Natural Progression, Standard 

Product Class in 2007 ...................................................................................................... 9-3 

Table 9.3. Distribution of BCs in Representative Product Class B by CSL....................9-4 

Classes in 2007 (as a Percentage of Total Shipments) ....................................................9-6 

Table 9.6. Distribution of External Power Supply Shipments by Efficiency – Part 1..... 9-7 

Table 9.7. Distribution of External Power Supply Shipments by Efficiency – Part 2..... 9-7 

Table 9.8. Distribution of 2.75-Watt External Power Supply Models by Efficiency...... 9-8 

Table 9.10. Base Case Shipments Growth Rates for BCs and EPSs...............................9-9 

Table 9.11. Static Scenario for Group A EPSs in the Base Case................................... 9-11 

Table 9.12. Dynamic Scenario for Group A EPSs in the Base Case ............................. 9-12 

Table 9.13. Example of a Roll-Up Response................................................................. 9-14 

Table 9.14. Example of a Shift Response ...................................................................... 9-14 

Table 9.15. List of Following Roll-Up and Shift Tables ............................................... 9-16 

Case................................................................................................................................ 9-17 

at CSL3, Roll-Up Response...........................................................................................9-18 

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EERE-2008-BT-STD-0005 COMMENT 03
Table 9.18. EPS Representative Product Class A, Dynamic Natural Progression, Standard 

at CSL3, Shift Response ................................................................................................ 9-19 

Table 9.19. EPS Representative Product Class B, Dynamic Natural Progression, Base 

Table 9.20. EPS Representative Product Class B, Dynamic Natural Progression, Standard 

Table 9.21. EPS Representative Product Class B, Dynamic Natural Progression, Standard 

Table 9.22. EPS Representative Product Class F, Dynamic Natural Progression, Base 

Table 9.23. EPS Representative Product Class F, Dynamic Natural Progression, Standard 

Table 9.24. EPS Representative Product Class F, Dynamic Natural Progression, Standard 

Case................................................................................................................................ 9-20 

at CSL3, Roll-Up Response...........................................................................................9-21 

at CSL3, Shift Response ................................................................................................ 9-22 

Case................................................................................................................................ 9-23 

at CSL3, Roll-Up Response...........................................................................................9-24 

at CSL3, Shift Response ................................................................................................ 9-25 

9-2
 

EERE-2008-BT-STD-0005 COMMENT 03
 

 

 

 

 

9.1 Current Year Shipments 

In its work on the determination analysis, DOE estimated that 70 million battery 

chargers and 397 million external power supplies were sold in the United States in 2007. 

DOE divided total shipments into the BC and EPS representative product classes 

described in chapter 3. 

9.1.1 Battery Charger Shipments 

Based on its analysis and input from manufacturers, DOE divided BC applications 

into three representative product classes, grouped by battery voltage. Because of the 

prevalence of fast chargers for professional power tool applications, the analysis of the 

high-voltage product class C further focused on two representative units differing in 

charge rate. Table 9.1 shows the distribution of BC shipments by representative product 

class. 

Table 9.1. Battery Charger Shipments by Representative Product Class in 2007 

Representative Product Class Dominant Applications Total Shipments 

(millions) 

Class A (0 to ≤ 3 V) Personal Care Products 5.1 

Classes B (>3 to ≤ 9 V) 

Kitchen Products 

Floor Care Products 

Universal BCs 

Digital Cameras 

Camcorders 

41.7 

Class C (> 9 V) Power Tools 22.8 

All Groups All Applications 69.6 

Table 9.2 shows the distribution of BC shipments by candidate standard level 

(CSL) used in the determination analysis. To divide the shipments of BCs among the 

CSLs (discussed in chapter 5 of the Draft Technical Report), DOE began with a large 

dataset published by the California Energy Commission, counting the number of models 

that met each CSL.1

 However, DOE included in the count only those BCs with a battery 

voltage close to those of the representative units. As a result, the sample sizes are 

relatively small. 

Table 9.2. Distribution of BC Shipments Across Efficiency Levels by Representative 

Product Class in 2007 

CSL Efficiency Level 

Class A 

(0 to ≤ 3 V) 

(percent) 

Class B 

(>3 to ≤ 9 V) 

(percent) 

Class C 

(>9 V) 

(percent) 

CSL0 Baseline 60 45 65 

CSL1 Slightly Improved 20 13 10 

CSL2 CEC Tier 1/ENERGY STAR 13 26 10 

CSL3 Beyond Standard 0 10 15 

CSL4 Best-in-Market Technology 7 6 0 

All Levels 100 100 100 

9-3
 

EERE-2008-BT-STD-0005 COMMENT 03
 

 

Product class A had a representative unit with a battery voltage of 1.2 volts, but 

DOE included in the count all units with a battery voltage between 0 volts and 3 volts to 

ensure an adequate sample size. Similarly, the representative unit for product class B had 

a battery voltage of 4.8 volts, but DOE included in the count all units with a battery 

voltage between 3.6 volts and 6 volts. For product class C, DOE included all BCs with a 

battery voltage between 18 volts and 19.2 volts. DOE did not differentiate between fast 

and slow models when counting BCs in this class. 

The final count used to distribute BCs among the CSLs included 15 units for 

representative product class A, 62 for product class B, and 20 for product class C. Table 

9.3 shows how representative units from the dataset were distributed among the CSLs for 

representative product class B. 

Table 9.3. Distribution of BCs in Representative Product Class B by CSL 

CSL Efficiency Level Number of Units, 

3.6 to 6 V Percent of Total 

CSL0 Base Line 33 45 

CSL1 Slightly Improved 8 13 

CSL2 CEC Tier 1/ENERGY STAR 22 26 

CSL3 Beyond Standard 6 10 

CSL4 Best-in-Market 7 6 

All Levels 62 100 

Because shipments data for the individual BCs in the dataset were not available, 

the BC models in the dataset that DOE included in the count were not weighted by their 

shipments. Thus, the base case distribution in Table 9.3 is only a rough representation of 

the population of BCs in the market. 

9.1.2 External Power Supply Shipments 

DOE divided EPSs into three representative product classes based on nameplate 

output power. However, many applications using an EPS spanned two product classes. 

DOE referred to prior work by the California Energy Commission on consumer 

electronic products for guidance on fitting applications into the three representative 

product classes.2 

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EERE-2008-BT-STD-0005 COMMENT 03
Table 9.4 shows the distribution of EPS application shipments across product classes; 

Table 9.5 shows the total EPS shipments in each product class. 

9-5
 

EERE-2008-BT-STD-0005 COMMENT 03
 

 

Table 9.4. Distribution of EPS Application Shipments Across Representative 

Product Classes in 2007 (as a Percentage of Total Shipments) 

Application Class A 

0 to < 4 W 

(percent) 

Class B 

≥ 4 to ≤ 60 W 

(percent) 

Class F 

> 60 W 

(percent 

All 

Classes 

(percent) 

Ink-Jet Computer Printers 0 100 0 100 

Notebook Computers 0 15 85 100 

Modems/Fax Modems 0 92 8 100 

LAN Equipment 0 100 0 100 

Wi-Fi Access Points 0 100 0 100 

Flat Panel Monitors 0 100 0 100 

Flatbed Scanners 0 100 0 100 

Medical Devices 10 87 3 100 

Portable Video Players 0 100 0 100 

Cordless Telephones 75 25 0 100 

Cellular Telephones 50 50 0 100 

Telephone Answering Devices 50 50 0 100 

Digital Cameras 25 75 0 100 

Portable Gaming Devices 0 100 0 100 

Small LCD Tvs 0 70 30 100 

Portable Audio Players 40 60 0 100 

Camcorders 0 100 0 100 

Table 9.5. External Power Supply Shipments by Representative Product Class in 

2007 

Representative Product Class Shipments (millions) 

Class A (0 to < 4 W) 112.2 

Class B (≥ 4 to ≤ 60 W) 249.5 

Class F (> 60 W) 35.5 

During work on the determination analysis, DOE found limited information on 

the distribution of shipments by efficiency level. The Darnell Group forecasted that in 

2007, 21 percent of EPSs on the market would use line-frequency technology and the 

remaining EPSs would use switched-mode technology.3 However, during the Scoping 

Workshop in January 2007, some stakeholders noted that this figure was too high.4 For 

simplicity, DOE assumed that line-frequency EPSs made up 20 percent of 2007 

shipments (79.4 million of 397.2 million total EPSs). Although some of the available 

line-frequency power supplies met CSL2, the specific number of shipments was 

unknown. DOE estimated that the number is likely to be very small. To simplify matters, 

DOE assumed that all line-frequency power supplies fell into CSL0, and divided the 

remaining 80 percent among the higher CSLs. 

Information gathered during work on the engineering analysis suggested that as 

output power increases, line-frequency power supplies become less common. DOE 

assumed product class F contained no line-frequency supplies. DOE also assumed that 

half of all line-frequency power supplies are in product class A (39.7 million of 112.2 

million EPSs) and half in product class B (39.7 million of 249.5 million EPSs). Thus, 35 

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EERE-2008-BT-STD-0005 COMMENT 03
 

 

 

 

 

 

 

 

 

 

 

percent of total shipments in product class A fell in CSL0. In product class B, 16 percent 

of total shipments fell in CSL0. 

Before CEC Tier 1 became a mandatory standard in California, a 2004 study 

completed by Pacific Gas and Electric estimated that 40 percent of the market already 

met the qualifications, which corresponded to CSL2.5 DOE assumed this 40 percent was 

distributed evenly across representative product classes.a

 In product class A, if 35 percent 

of EPSs are in CSL0 and 40 percent meet CSL2 or better, then the remaining 25 percent 

meet CSL1. Applying this logic to representative product classes B and F, CSL1 

comprises 44 and 60 percent of EPSs in each class, respectively (Table 9.6). 

Table 9.6. Distribution of External Power Supply Shipments by Efficiency – Part 1 

CSL Efficiency Level 

Group A 

(0 to < 4 W) 

(percent) 

Group B 

(≥ 4 to ≤ 60 W) 

(percent) 

Group F 

(> 60 W) 

(percent) 

CSL0 Baseline Line Frequency 35 16 0 

CSL1 Baseline SMPS 25 44 60 

CSL2 CEC 1 

40 40 40 

CSL3 CEC 2 

CSL4 > CEC 2 

CSL5 Market Best 

CSL6 Max Tech 

All Levels 100 100 100 

The study further estimated that 25 percent of the 2004 EPS market was at least as 

efficient as CEC Tier 2 Standards, corresponding to CSL3. With this information, DOE 

calculated the percentage of EPSs in CSL2 as 15 percent - the remainder of the original 

40 percent meeting CEC Tier 1 or better (Table 9.7). DOE assumed that no products on 

the market met the max-tech efficiency level (CSL6). 

Table 9.7. Distribution of External Power Supply Shipments by Efficiency – Part 2 

CSL Efficiency Level 

Group A 

0 to < 4 W 

(percent) 

Group B 

≥ 4 to ≤ 60 W 

(percent) 

Group F 

> 60 W 

(percent) 

CSL0 Baseline Line Frequency 35 16 0 

CSL1 Baseline SMPS 25 44 60 

CSL2 CEC 1 15 15 15 

CSL3 CEC 2 

CSL4 > CEC 2 25 25 25

CSL5 Market Best 

CSL6 Max Tech 0 0 0 

Total 100 100 100 

To divide the final 25 percent of shipments among CSL3, CSL4, and CSL5, DOE 

used the ENERGY STAR list of qualified EPS units.6

 DOE examined a subset of EPSs 

a

 The CEC Tier 1 standard that California adopted is slightly more stringent than that suggested by the 

literature above. This should not have a significant impact on the percentage of the market that already met 

the standard. 

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EERE-2008-BT-STD-0005 COMMENT 03
 

 

 

 

 

 

whose nameplate output power matched that of the representative units (developed in the 

engineering analysis) in each representative product class. Units selected met or exceeded 

CSL3 active mode efficiency. The list included 10 units at 2.75 watts, 39 units at 

18 watts, and 16 units at 120 watts, which were then divided among CSL3, CSL4, and 

CSL5. Table 9.8 shows the categorization of units at 2.75 watts by active mode 

efficiency. DOE applied the same technique to representative product classes B and F. 

Because shipments data for the individual EPSs in the data set were not available DOE 

did not weight the EPSs in CSL3, CSL4, and CSL5 by their shipments. Thus, the 

distribution in those CSLs may not have accurately represented the population of EPSs 

shipped to the market. 

Table 9.8. Distribution of 2.75-Watt External Power Supply Models by Efficiency 

CSL Name Number of Units, 

2.75 W 

Percent of Total 

CSL3 CEC 2 5 50 

CSL4 > CEC 2 4 40 

CSL5 Market Best 1 10 

CSL6 Max Tech 0 0 

Total 10 100 

This last piece of information provides the entire distribution of shipments across 

efficiency levels that DOE used in its determination analysis. 

Table 9.9. Final Distribution of Shipments by Efficiency for External Power 

Supplies 

CSL Name Group A 

0 to < 4 W 

(percent) 

Group B 

≥ 4 to ≤ 60 W 

(percent) 

Group F 

> 60 W 

(percent) 

CSL0 Baseline Line Frequency 35 16 0 

CSL1 Baseline SMPS 25 44 60 

CSL2 CEC 1 15 15 15 

CSL3 CEC 2 12 6 9 

CSL4 > CEC 2 10 18 5 

CSL5 Market Best 3 1 11 

CSL6 Max Tech 0 0 0 

9.2 Base Case Shipments Forecasts 

9.2.1 Total Annual Shipments 

To evaluate the various impacts of standards, DOE developed a base case 

shipments forecast against which to compare the standards case shipments forecasts 

developed for each CSL. For the determination analysis, DOE designed the base case 

forecasts based on what it anticipated would happen to energy consumption and energy 

costs over time if federal energy conservation standards were not adopted. In determining 

the base case forecasts, DOE considered historical shipments, the mix of BC and EPS 

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EERE-2008-BT-STD-0005 COMMENT 03
 

 

efficiencies currently sold, and how that mix might change over time if new standards are 

not adopted. 

The base case shipments model tracked the aging and replacement of BCs and 

EPSs given product lifetimes (chapter 8) and projected future BC and EPS sales growth. 

Shipments growth rates for many applications using BCs and EPSs have been historically 

high. This has been especially true for higher-wattage EPS applications. Also, as 

applications incorporate more features, output powers have risen to accommodate them. 

For example, compared to a basic cellular telephone, cellular telephones that incorporate 

a digital camera and PDA functionality require a higher-capacity battery and therefore an 

EPS with a higher output power to charge it. 

In the determination analysis, DOE used the constant annual growth rates in Table 

9.10 as reference values. These growth rates considered historic shipments of BCs and 

EPSs, market saturation of those products, and U.S. population growth. High saturation 

of consumer products would tend to slow growth in BC and EPS shipments. DOE 

considered population growth, which was projected to average 0.79 percent per year 

during the analysis period (2014 to 2039) to be the lower bound of its considered growth 

rates.7 

Because recent improvements in battery charging systems such as shorter charge 

times helped increase demand for BCs, DOE estimated growth rates to be 4 percent per 

year for each BC product class. Because of a high saturation of cellular telephones and 

their dominance in the 0 to 4 watt EPS category, DOE estimated growth to be only 2 

percent per year over the analysis period for this product class. EPSs with higher output 

have been growing more quickly in recent years, with the highest output category 

experiencing the fastest growth and the least saturation. DOE estimated that EPSs 

between 4 and 60 watts would grow 3 percent per year and EPSs above 60 watts would 

grow 4 percent per year between 2014 and 2039. 

Table 9.10. Base Case Shipments Growth Rates for BCs and EPSs 

Battery Chargers Compound Annual 

Growth Rate 

(percent) 

All Representative Product Classes 4 

External Power Supplies Compound Annual 

Growth Rate 

(percent) 

Representative Product Class A (0 to < 4 W) 2 

Representative Product Class B (≥ 4 and ≤ 60 W) 3 

Representative Product Class F (> 60 W) 4 

9.2.2 Natural Progression of Efficiency Over Time 

To provide an upper and lower bound for estimated energy savings in the NIA, 

DOE considered two possibilities for the natural market state of efficiencies over time. 

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EERE-2008-BT-STD-0005 COMMENT 03
Natural in this case referred to improvements in efficiency that might take place 

independent of a federal standard. These two market states, static and dynamic, presented 

situations in which the BC and EPS markets would experience either no improvement in 

efficiency (static) or progressive improvements in efficiency (dynamic). 

To simplify calculations, DOE assumed that the natural market state could be 

either static or dynamic, but that the market could not change states within the period of 

analysis. That is, markets could not change from static to dynamic or from dynamic to 

static. 

The static market state represented the case in which there would be no 

progression toward higher efficiency. Because the efficiency of BCs or EPSs would 

remain unchanged outside a standard, scenarios with a static market state represented 

cases in which a standard would have the most impact in generating energy savings and 

thus provided an upper bound for energy savings. As reflected in the National Energy 

Savings model, a static natural market state was represented by an unchanging 

distribution of efficiencies over time. Table 9.11 gives the static scenario for group A 

EPSs in the base case (no standard) as calculated for the NES in the determination 

analysis. Although only EPS tables are provided as examples, the same model would 

apply to BCs; however, DOE did not complete equivalent tables for BCs for the 

determination analysis. 

9-10
 

EERE-2008-BT-STD-0005 COMMENT 03
 

Table 9.11. Static Scenario for Group A EPSs in the Base Case 

Year 

Distribution of Shipments Across Efficiency Levels (percent) 

CSL0 CSL1 CSL2 CSL3 CSL4 CSL5 CSL6 

2007 35 25 15 12 10 3 0 

2008 35 25 15 12 10 3 0 

2009 35 25 15 12 10 3 0 

2010 35 25 15 12 10 3 0 

2011 35 25 15 12 10 3 0 

2012 35 25 15 12 10 3 0 

2013 35 25 15 12 10 3 0 

2014 35 25 15 12 10 3 0 

2015 35 25 15 12 10 3 0 

2016 35 25 15 12 10 3 0 

2017 35 25 15 12 10 3 0 

2018 35 25 15 12 10 3 0 

2019 35 25 15 12 10 3 0 

2020 35 25 15 12 10 3 0 

2021 35 25 15 12 10 3 0 

2022 35 25 15 12 10 3 0 

2023 35 25 15 12 10 3 0 

2024 35 25 15 12 10 3 0 

2025 35 25 15 12 10 3 0 

2026 35 25 15 12 10 3 0 

2027 35 25 15 12 10 3 0 

2028 35 25 15 12 10 3 0 

2029 35 25 15 12 10 3 0 

2030 35 25 15 12 10 3 0 

2031 35 25 15 12 10 3 0 

2032 35 25 15 12 10 3 0 

2033 35 25 15 12 10 3 0 

2034 35 25 15 12 10 3 0 

2035 35 25 15 12 10 3 0 

2036 35 25 15 12 10 3 0 

2037 35 25 15 12 10 3 0 

2038 35 25 15 12 10 3 0 

The dynamic market state represented the case in which the BC and EPS market 

would progress toward higher efficiency regardless of the presence of a standard. 

Because the efficiencies of BCs and EPSs would improve naturally, scenarios with a 

dynamic market state represented cases in which a standard would have the least impact 

on generating energy savings, and thus provided the lower bound for energy savings. 

During its work on the determination analysis, DOE assumed that a dynamic 

market state would progress toward CSL5 (Best-in-Market Technology), with 100 

percent of production in CSL5 in the last year of the analysis period. To reflect the 

assumption of diminishing returns on efficiency improvements, the time for each 

subsequent progression step was increased, i.e., while the progression from CSL0 to 

CSL1 would take only 3 years, the progression from CSL1 to CSL2 would take 4 years, 

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EERE-2008-BT-STD-0005 COMMENT 03
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

the progression from CSL2 to CSL3 would take 6 years, etc. Table 9.12 gives the 

dynamic scenario for class A EPSs in the base case (no standard) as calculated for the 

NES in the determination analysis. 

Table 9.12. Dynamic Scenario for Group A EPSs in the Base Case 

Year 

Distribution of Shipments Across Efficiency Levels (percent) 

CSL0 CSL1 CSL2 CSL3 CSL4 CSL5 CSL6 

2007 35 25 15 12 10 3 0 

2008 23 33 17 13 10 5 0 

2009 12 40 18 13 11 6 0 

2010 0 48 20 14 11 8 0 

2011 0 36 29 14 11 9 0 

2012 0 24 39 15 12 11 0 

2013 0 12 48 16 12 12 0 

2014 0 0 58 17 12 14 0 

2015 0 0 48 25 13 15 0 

2016 0 0 38 33 13 16 0 

2017 0 0 29 41 13 17 0 

2018 0 0 19 50 14 18 0 

2019 0 0 10 58 14 19 0 

2020 0 0 0 66 15 20 0 

2021 0 0 0 58 22 21 0 

2022 0 0 0 49 29 21 0 

2023 0 0 0 41 36 22 0 

2024 0 0 0 33 44 23 0 

2025 0 0 0 25 51 24 0 

2026 0 0 0 16 58 25 0 

2027 0 0 0 8 66 26 0 

2028 0 0 0 0 73 27 0 

2029 0 0 0 0 66 34 0 

2030 0 0 0 0 59 42 0 

2031 0 0 0 0 51 49 0 

2032 0 0 0 0 44 56 0 

2033 0 0 0 0 37 63 0 

2034 0 0 0 0 29 71 0 

2035 0 0 0 0 22 78 0 

2036 0 0 0 0 15 85 0 

2037 0 0 0 0 7 93 0 

2038 0 0 0 0 0 100 0 

9.3 Standards Case Shipments Forecasts 

After calculating the volume of shipments and distribution across efficiency levels 

in the base case, DOE considered the market response to the standard with respect to (1) 

the total volume of shipments, and (2) the distribution of those shipments across 

efficiency levels. 

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EERE-2008-BT-STD-0005 COMMENT 03
9.3.1 Impact of Standards on Total Annual Shipments 

For the determination analysis, DOE made the simplifying assumption that the 

aggregate demand for BCs and EPSs would be the same in the standards case as in the 

base case. This assumption was based on two factors. First, the cost of BCs and EPSs 

would not increase much relative to the cost of the application; therefore, the increased 

manufacturing cost would not materially affect consumer demand. Second, the 

substitution options for BCs and EPSs are limited due to the design considerations and 

functionality of BCs and EPSs. That is, designers cannot easily substitute another power 

supply technology when size or the ability to operate without mains power are important 

attributes of the product. Therefore, DOE assumed that standards would have no impact 

on the volume of shipments of BCs and EPSs, and the shipment growth rate as calculated 

in section 9.2.1 could be used for both base and standards cases. 

9.3.2 Impact of Standards on Distribution of Shipments Across Efficiency Levels 

To account for the change in distribution across efficiencies due to a standard, 

DOE considered two possibilities for how manufacturers would adapt production: roll-up 

and shift. Note that these two responses occur between the year immediately preceding 

the standard and the year the standard takes effect, and are intended to reflect the 

immediate need of the market to comply with the increased efficiency required by the 

standard. 

9.3.2.1 Roll-Up Response 

In the roll-up scenario, DOE assumed that manufacturers would stop producing 

units that did not meet the standard but would maintain total production levels by 

producing more of those units that just met the standard. Looking at the overall 

distribution of efficiencies in the marketplace, those units that did not meet the standard 

would be “rolled up” to the minimum efficiency level set by the standard, while units 

already meeting the standard would remain unchanged. This response gives a lower 

bound on energy savings, because the roll-up response represents the minimum possible 

improvement in energy efficiency. 

Table 9.13 gives an example of a roll-up response to a standard set at CSL2 for 

EPSs in representative product class A. In the year before the effective date of the 

standard (2013), units are produced at all efficiency levels. The year the standard takes 

effect (2014), units at CSL0 and CSL1 no longer meet the efficiency required by the 

standard. As a result, the units produced at those levels are rolled up to CSL2. Thus: 

•	 the 35 percent of the market at CSL0 and the 25 percent of the market at 

CSL1 are rolled up and added to the 15 percent of the market at CSL2; and 

•	 the portions of the market at CSL3, CSL4, and CSL5 are unaffected and are 

carried down with no changes. 

9-13
 

EERE-2008-BT-STD-0005 COMMENT 03
 

 

 

 

 

 

Table 9.13. Example of a Roll-Up Response 

Distribution of Shipments Across Efficiency Levels (percent) 

Year CSL0 CSL1 CSL2 CSL3 CSL4 CSL5 

2013 35 25 15 12 10 3 

2014 0 0 75 12 10 3 

9.3.2.2 Shift Response 

In the shift scenario, DOE assumed that manufacturers would respond to a 

standard by improving those units that did not meet the standard, but would also improve 

units that already met the standard. In the shift scenario, the distribution of products 

across efficiency levels remains the same, but the base level of existing production is 

shifted to the standard level, and higher levels are shifted the same number of levels, with 

a cap at the best-in-market level (CSL5). This response gives an upper bound on energy 

savings. 

Table 9.14 gives an example of a shift response to a standard (with an effective 

start date of 2014) set at CSL2 for EPSs in Representative Product Class A. In the year 

before the standard (2013), units are produced at all efficiency levels. The year the 

standard takes effect (2014), units at CSL0 and CSL1 no longer meet the efficiency 

required by the standard. As a result, the entire distribution moves, so that the portion of 

the market at the lowest efficiency level (CSL0) shifts up to the minimum level required 

by the standard (CSL2), while the portions of the market at all other levels shift the same 

number of levels. No units exceed CSL5. Thus: 

• the 35 percent of the market at CSL0 shifts up to CSL2; 

• the 25 percent of the market at CSL1 shifts up to CSL3; 

• the 15 percent of the market at CSL2 shifts up to CSL4; 

• the 12 percent of the market at CSL3 shifts up to CSL5; and 

• the 10 percent of the market at CSL4 shifts up to CSL5 (due to the cap); while 

• the 3 percent of the market at CSL5 is unaffected. 

Table 9.14. Example of a Shift Response 

Distribution of Shipments Across Efficiency Levels (percent) 

Year CSL0 CSL1 CSL2 CSL3 CSL4 CSL5 

2013 35 25 15 12 10 3 

2014 0 0 35 25 15 25 

9.3.3 Adjusting Dynamic Progression Rates Following the Standard 

In those scenarios with a dynamic market state, DOE assumed that units would 

continue to improve in efficiency following the market’s initial response to the standard. 

However, DOE chose not to consider efficiency levels beyond the available best-inmarket technologies, because such levels would be speculative. Therefore, DOE adjusted 

the progression rate following the market response. Efficiency would progress toward 

100 percent distribution at CSL5, limiting potential energy savings to bounds based on 

9-14
 

EERE-2008-BT-STD-0005 COMMENT 03
practical technologies, rather than the max-tech technologies at CSL6. Figure 9.1 

provides a visual representation of an adjusted progression rate in the standards case. 

Progression in a Dynamic Market State 

2007 

2009 

2011 

2013 

2015 

2017 

2019 

2021 

2023 

2025 

2027 

2029 

2031 

2033 

2035 

2037 

2039 

Year 

Efficiency 

B a se C a se S t an da rd C a s e 

Figure 9.1. Progression in a Dynamic Market State 

Tables 16 to 24 give an example of how the dynamic progression in the base case 

would eventually catch up with the accelerated progression in the standards case. By the 

end of the analysis period, however, the distributions in the base case eventually catch up 

to the standards case. 

Tables 16 to 24 are further examples of the roll-up and shift responses to 

standards in the context of a dynamic market state. For all tables except the first, which 

represents the base case, DOE used the standard level of CSL3. These tables reflect 

actual tables DOE calculated for the determination analysis. 

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EERE-2008-BT-STD-0005 COMMENT 03
Table 9.15. List of Following Roll-Up and Shift Tables 

EPS Representative 

Product Class 

Base Case Roll-Up Response to 

Standard 

Shift Response to 

Standard 

A Table 9.16 Table 9.17 Table 9.18 

B Table 9.19 Table 9.20 Table 9.21 

F Table 9.22 Table 9.23 Table 9.24 

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Table 9.16. EPS Representative Product Class A, Dynamic Natural Progression, 

Base Case 

Year 

Percent of Market at Each Efficiency Level 

CSL0 CSL1 CSL2 CSL3 CSL4 CSL5 

2007 35 25 15 12 10 3 

2008 23 33 17 13 10 5 

2009 12 40 18 13 11 6 

2010 0 48 20 14 11 8 

2011 0 36 29 14 11 9 

2012 0 24 39 15 12 11 

2013 0 12 48 16 12 12 

2014 0 0 58 17 12 14 

2015 0 0 48 25 13 15 

2016 0 0 38 33 13 16 

2017 0 0 29 41 13 17 

2018 0 0 19 50 14 18 

2019 0 0 10 58 14 19 

2020 0 0 0 66 15 20 

2021 0 0 0 58 22 21 

2022 0 0 0 49 29 21 

2023 0 0 0 41 36 22 

2024 0 0 0 33 44 23 

2025 0 0 0 25 51 24 

2026 0 0 0 16 58 25 

2027 0 0 0 8 66 26 

2028 0 0 0 0 73 27 

2029 0 0 0 0 66 34 

2030 0 0 0 0 59 42 

2031 0 0 0 0 51 49 

2032 0 0 0 0 44 56 

2033 0 0 0 0 37 63 

2034 0 0 0 0 29 71 

2035 0 0 0 0 22 78 

2036 0 0 0 0 15 85 

2037 0 0 0 0 7 93 

2038 0 0 0 0 0 100 

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Table 9.17. EPS Representative Product Class A, Dynamic Natural Progression, 

Standard at CSL3, Roll-Up Response 

Year 

Percent of Market at Each Efficiency Level 

CSL0 CSL1 CSL2 CSL3 CSL4 CSL5 

2007 35 25 15 12 10 3 

2008 23 33 17 13 10 5 

2009 12 40 18 13 11 6 

2010 0 48 20 14 11 8 

2011 0 36 29 14 11 9 

2012 0 24 39 15 12 11 

2013 0 12 48 16 12 12 

2014 0 0 0 74 12 14 

2015 0 0 0 68 17 15 

2016 0 0 0 62 23 16 

2017 0 0 0 56 28 17 

2018 0 0 0 50 33 18 

2019 0 0 0 43 38 19 

2020 0 0 0 37 43 20 

2021 0 0 0 32 45 22 

2022 0 0 0 28 47 25 

2023 0 0 0 23 49 28 

2024 0 0 0 19 51 30 

2025 0 0 0 14 53 33 

2026 0 0 0 9 55 36 

2027 0 0 0 5 57 39 

2028 0 0 0 0 59 41 

2029 0 0 0 0 53 47 

2030 0 0 0 0 47 53 

2031 0 0 0 0 41 59 

2032 0 0 0 0 35 65 

2033 0 0 0 0 29 71 

2034 0 0 0 0 24 77 

2035 0 0 0 0 18 82 

2036 0 0 0 0 12 88 

2037 0 0 0 0 6 94 

2038 0 0 0 0 0 100 

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Table 9.18. EPS Representative Product Class A, Dynamic Natural Progression, 

Standard at CSL3, Shift Response 

Year 

Percent of Market at Each Efficiency Level 

CSL0 CSL1 CSL2 CSL3 CSL4 CSL5 

2007 35 25 15 12 10 3 

2008 23 33 17 13 10 5 

2009 12 40 18 13 11 6 

2010 0 48 20 14 11 8 

2011 0 36 29 14 11 9 

2012 0 24 39 15 12 11 

2013 0 12 48 16 12 12 

2014 0 0 0 12 48 40 

2015 0 0 0 11 45 44 

2016 0 0 0 10 42 48 

2017 0 0 0 9 39 52 

2018 0 0 0 8 36 56 

2019 0 0 0 7 33 60 

2020 0 0 0 6 30 64 

2021 0 0 0 5 29 66 

2022 0 0 0 4 28 68 

2023 0 0 0 4 27 70 

2024 0 0 0 3 25 72 

2025 0 0 0 2 24 73 

2026 0 0 0 1 23 75 

2027 0 0 0 1 22 77 

2028 0 0 0 0 21 79 

2029 0 0 0 0 19 81 

2030 0 0 0 0 17 83 

2031 0 0 0 0 15 85 

2032 0 0 0 0 13 87 

2033 0 0 0 0 10 90 

2034 0 0 0 0 8 92 

2035 0 0 0 0 6 94 

2036 0 0 0 0 4 96 

2037 0 0 0 0 2 98 

2038 0 0 0 0 0 100 

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Table 9.19. EPS Representative Product Class B, Dynamic Natural Progression, 

Base Case 

Year 

Percent of Market at Each Efficiency Level 

CSL0 CSL1 CSL2 CSL3 CSL4 CSL5 

2007 15 45 15 6 18 1 

2008 10 43 20 8 16 4 

2009 5 40 25 9 14 7 

2010 0 38 30 11 12 10 

2011 0 28 36 13 12 12 

2012 0 19 41 15 12 13 

2013 0 9 47 18 11 15 

2014 0 0 53 20 11 16 

2015 0 0 44 27 12 17 

2016 0 0 35 34 13 18 

2017 0 0 26 41 14 19 

2018 0 0 18 49 14 20 

2019 0 0 9 56 15 21 

2020 0 0 0 63 16 22 

2021 0 0 0 55 23 23 

2022 0 0 0 47 29 24 

2023 0 0 0 39 36 25 

2024 0 0 0 31 43 26 

2025 0 0 0 23 50 27 

2026 0 0 0 16 57 28 

2027 0 0 0 8 64 29 

2028 0 0 0 0 71 30 

2029 0 0 0 0 63 37 

2030 0 0 0 0 56 44 

2031 0 0 0 0 49 51 

2032 0 0 0 0 42 58 

2033 0 0 0 0 35 65 

2034 0 0 0 0 28 72 

2035 0 0 0 0 21 79 

2036 0 0 0 0 14 86 

2037 0 0 0 0 7 93 

2038 0 0 0 0 0 100 

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Table 9.20. EPS Representative Product Class B, Dynamic Natural Progression, 

Standard at CSL3, Roll-Up Response 

Year 

Percent of Market at Each Efficiency Level 

CSL0 CSL1 CSL2 CSL3 CSL4 CSL5 

2007 15 45 15 6 18 1 

2008 10 43 20 8 16 4 

2009 5 40 25 9 14 7 

2010 0 38 30 11 12 10 

2011 0 28 36 13 12 12 

2012 0 19 41 15 12 13 

2013 0 9 47 18 11 15 

2014 0 0 0 73 11 16 

2015 0 0 0 67 16 17 

2016 0 0 0 61 22 18 

2017 0 0 0 55 27 19 

2018 0 0 0 49 32 20 

2019 0 0 0 42 37 21 

2020 0 0 0 36 42 22 

2021 0 0 0 32 44 24 

2022 0 0 0 27 46 27 

2023 0 0 0 23 48 30 

2024 0 0 0 18 50 32 

2025 0 0 0 14 52 35 

2026 0 0 0 9 54 37 

2027 0 0 0 5 55 40 

2028 0 0 0 0 57 43 

2029 0 0 0 0 52 48 

2030 0 0 0 0 46 54 

2031 0 0 0 0 40 60 

2032 0 0 0 0 34 66 

2033 0 0 0 0 29 71 

2034 0 0 0 0 23 77 

2035 0 0 0 0 17 83 

2036 0 0 0 0 11 89 

2037 0 0 0 0 6 94 

2038 0 0 0 0 0 100 

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Table 9.21. EPS Representative Product Class B, Dynamic Natural Progression, 

Standard at CSL3, Shift Response 

Year 

Percent of Market at Each Efficiency Level 

CSL0 CSL1 CSL2 CSL3 CSL4 CSL5 

2007 15 45 15 6 18 1 

2008 10 43 20 8 16 4 

2009 5 40 25 9 14 7 

2010 0 38 30 11 12 10 

2011 0 28 36 13 12 12 

2012 0 19 41 15 12 13 

2013 0 9 47 18 11 15 

2014 0 0 0 9 47 44 

2015 0 0 0 9 44 48 

2016 0 0 0 8 41 52 

2017 0 0 0 7 38 55 

2018 0 0 0 6 34 59 

2019 0 0 0 5 31 63 

2020 0 0 0 5 28 67 

2021 0 0 0 4 27 69 

2022 0 0 0 4 26 71 

2023 0 0 0 3 25 72 

2024 0 0 0 2 23 74 

2025 0 0 0 2 22 76 

2026 0 0 0 1 21 78 

2027 0 0 0 1 20 79 

2028 0 0 0 0 19 81 

2029 0 0 0 0 17 83 

2030 0 0 0 0 15 85 

2031 0 0 0 0 13 87 

2032 0 0 0 0 11 89 

2033 0 0 0 0 9 91 

2034 0 0 0 0 8 93 

2035 0 0 0 0 6 94 

2036 0 0 0 0 4 96 

2037 0 0 0 0 2 98 

2038 0 0 0 0 0 100 

9-22
 

EERE-2008-BT-STD-0005 COMMENT 03
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 9.22. EPS Representative Product Class F, Dynamic Natural Progression, 

Base Case 

Year 

Percent of Market at Each Efficiency Level 

CSL0 CSL1 CSL2 CSL3 CSL4 CSL5 

2007 0 60 15 9 5 11 

2008 0 50 23 10 6 12 

2009 0 40 30 11 6 13 

2010 0 30 38 12 7 14 

2011 0 23 40 15 8 14 

2012 0 15 43 18 8 15 

2013 0 8 46 22 9 16 

2014 0 0 49 25 10 17 

2015 0 0 41 31 11 18 

2016 0 0 33 37 12 19 

2017 0 0 24 43 13 19 

2018 0 0 16 49 15 20 

2019 0 0 8 55 16 21 

2020 0 0 0 61 17 22 

2021 0 0 0 53 24 23 

2022 0 0 0 46 30 24 

2023 0 0 0 38 37 25 

2024 0 0 0 31 43 26 

2025 0 0 0 23 50 27 

2026 0 0 0 15 57 28 

2027 0 0 0 8 63 29 

2028 0 0 0 0 70 30 

2029 0 0 0 0 63 37 

2030 0 0 0 0 56 44 

2031 0 0 0 0 49 51 

2032 0 0 0 0 42 58 

2033 0 0 0 0 35 65 

2034 0 0 0 0 28 72 

2035 0 0 0 0 21 79 

2036 0 0 0 0 14 86 

2037 0 0 0 0 7 93 

2038 0 0 0 0 0 100 

9-23
 

EERE-2008-BT-STD-0005 COMMENT 03
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 9.23. EPS Representative Product Class F, Dynamic Natural Progression, 

Standard at CSL3, Roll-Up Response 

Year 

Percent of Market at Each Efficiency Level 

CSL0 CSL1 CSL2 CSL3 CSL4 CSL5 

2007 0 60 15 9 5 11 

2008 0 50 23 10 6 12 

2009 0 40 30 11 6 13 

2010 0 30 38 12 7 14 

2011 0 23 40 15 8 14 

2012 0 15 43 18 8 15 

2013 0 8 46 22 9 16 

2014 0 0 0 74 10 17 

2015 0 0 0 67 15 18 

2016 0 0 0 61 20 19 

2017 0 0 0 55 26 19 

2018 0 0 0 49 31 20 

2019 0 0 0 43 36 21 

2020 0 0 0 37 42 22 

2021 0 0 0 32 44 24 

2022 0 0 0 28 46 27 

2023 0 0 0 23 48 30 

2024 0 0 0 18 50 32 

2025 0 0 0 14 52 35 

2026 0 0 0 9 54 37 

2027 0 0 0 5 56 40 

2028 0 0 0 0 58 43 

2029 0 0 0 0 52 48 

2030 0 0 0 0 46 54 

2031 0 0 0 0 40 60 

2032 0 0 0 0 35 66 

2033 0 0 0 0 29 71 

2034 0 0 0 0 23 77 

2035 0 0 0 0 17 83 

2036 0 0 0 0 12 89 

2037 0 0 0 0 6 94 

2038 0 0 0 0 0 100 

9-24
 

EERE-2008-BT-STD-0005 COMMENT 03
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 9.24. EPS Representative Product Class F, Dynamic Natural Progression, 

Standard at CSL3, Shift Response 

Year 

Percent of Market at Each Efficiency Level 

CSL0 CSL1 CSL2 CSL3 CSL4 CSL5 

2007 0 60 15 9 5 11 

2008 0 50 23 10 6 12 

2009 0 40 30 11 6 13 

2010 0 30 38 12 7 14 

2011 0 23 40 15 8 14 

2012 0 15 43 18 8 15 

2013 0 8 46 22 9 16 

2014 0 0 0 8 46 47 

2015 0 0 0 7 43 50 

2016 0 0 0 6 40 54 

2017 0 0 0 6 36 58 

2018 0 0 0 5 33 62 

2019 0 0 0 4 30 66 

2020 0 0 0 4 27 70 

2021 0 0 0 3 26 71 

2022 0 0 0 3 24 73 

2023 0 0 0 2 23 75 

2024 0 0 0 2 22 76 

2025 0 0 0 1 21 78 

2026 0 0 0 1 20 80 

2027 0 0 0 0 18 81 

2028 0 0 0 0 17 83 

2029 0 0 0 0 15 85 

2030 0 0 0 0 14 86 

2031 0 0 0 0 12 88 

2032 0 0 0 0 10 90 

2033 0 0 0 0 9 91 

2034 0 0 0 0 7 93 

2035 0 0 0 0 5 95 

2036 0 0 0 0 3 97 

2037 0 0 0 0 2 98 

2038 0 0 0 0 0 100 

References 

1

 Blosser, J., H. Kameth, et al. (2006). Battery Charger Laboratory Test Data File. 

California Energy Commission Public Interest Energy Research Funding.

2

 TIAX LLC. “Assessment of Analyses Performed for the California Energy Efficiency 

Regulations for Consumer Electronics Products.” Prepared by TIAX for California 

Energy Commission. 2 February 2006. TIAX LLC: Cambridge, MA. Distributions used 

were updates to the distribution created by the Darnell Group in 2005 (cited elsewhere in 

this document). 

3

 Darnell Group. External AC-DC Power Supplies: Global Market Forecasts and 

Competitive Environment. 2nd Edition. 2005. Darnell Group: Corona, California. 

9-25
 

EERE-2008-BT-STD-0005 COMMENT 03
 4

 Pacific Gas and Electric. Comments from the Scoping Workshop on Battery Chargers 

and External Power Supplies.. June 29, 2007.

5

 Fernstrom, Gary. Codes and Standards Enhancement Initiative For PY2004: Title 20 

Standards Development Analysis of Standards Options For Single-Voltage External AC 

to DC Power Supplies. May 2004. Prepared by Ecos Consulting et al. for Pacific Gas and 

Electric. 

6

 Environmental Protection Agency. Qualified Product (QP) List for ENERGY STAR® 

Ac-Dc Qualified External Power Supplies. 

http://www.energystar.gov/ia/products/prod_lists/eps_ac_dc_prod_list.pdf. Last accessed 

December 17, 2007. 

7

 United States Census Bureau. U.S. Interim Projections by Age, Sex, Race, and Hispanic 

Origin. . March 2004. 

9-26
 

EERE-2008-BT-STD-0005 COMMENT 03
CHAPTER 10. NATIONAL IMPACT ANALYSIS 

10.1 Introduction.................................................................................................... 10-2 

10.2 Unit Energy Savings ...................................................................................... 10-2 

10.3 National Inventory ......................................................................................... 10-3 

10.4 National Energy Savings................................................................................ 10-5 

10.5 National Net Present Value............................................................................ 10-5 

LIST OF FIGURES 

Figure 10.1. Flow Diagram of the Calculation of UES ................................................. 10-3 

Figure 10.2. Flow Chart of the Calculation of National Inventory................................10-4 

Figure 10.3. Flow Chart of the Calculation of NES ...................................................... 10-5 

Figure 10.4. Flow Chart of the Calculation of NPV...................................................... 10-6 

LIST OF TABLES 

Table 10.1 Sample National Inventory Table ................................................................10-4 

10-1
 

EERE-2008-BT-STD-0005 COMMENT 03
10.1 Introduction 

For the determination analysis, DOE intended to use the national impact analysis 

to measure the affects of Federal energy conservation standards by comparing projected 

U.S. energy consumption with and without new energy conservation standards. 

Aggregate impacts combined projections of unit energy consumption of new battery 

chargers and external power supplies, annual equipment shipments, and the price of 

purchased equipment. Approaches to determining unit energy consumption are described 

in chapter 6, methods for deriving base case shipment forecasts are discussed in 

chapter 9, and approaches to determining retail prices for products are described in 

chapter 7. 

The national impact analysis consisted of four calculations: 

•	 Unit energy savings (UES), which measured the change in unit energy 

consumption due to the impact of the standard (section 10.2); 

•	 National inventory, which measured the total number of units affected by the 

standard (section 10.3); 

•	 National energy savings (NES), which combined unit energy savings and the 

national inventory to obtain the aggregate energy savings generated by the 

standard (section 10.4); and 

•	 Net present value, which calculated the net present savings and costs of a 

standard by comparing the present value of energy savings from national 

energy savings with the present value of the increased consumer purchase 

costs associated with the standard (section 10.5). 

10.2 Unit Energy Savings 

The unit energy savings is the difference between the unit energy consumption 

(UEC) in the standard case and the UEC in the base case. Thus, the UES represents the 

reduced energy consumption of a single unit due to the higher efficiency generated by a 

standard. Once calculated, the UES would then be multiplied by the national inventory of 

units to calculate national energy savings. 

For each representative product class, DOE calculated the shipment-weighted 

average UEC of products in that class sold in a given year. Chapter 6 provides the UEC 

of products at each candidate standard level (CSL); chapter 9 provides the proportion of 

total shipments at each CSL. DOE calculated weighted-average UECs for each year in 

the evaluation period in both the standards case and the base case. DOE then calculated 

UES by taking the difference between the two cases (Figure 10.1). 

10-2
 

EERE-2008-BT-STD-0005 COMMENT 03
Calculation of Unit Energy Savings 

Inputs 

Unit Energy 

Consumption by 

Efficiency Level 

Base Case 

Distribution of 

Shipments Across 

Efficiency Levels 

Standard Case 

Distribution of 

Shipments Across 

Efficiency Levels 

Standard Case 

Unit Energy 

Consumption 

Base Case 

Unit Energy 

Consumption 

Unit Energy Savings 

Figure 10.1. Flow Diagram of the Calculation of UES 

10.3 National Inventory 

DOE used the national inventory to represent the installed base of BCs and EPSs 

that a standard would affect. Because the BCs and EPSs remain in use for several years, 

the national inventory represents the stock of BCs or EPSs in service for any given year 

of the analysis period. It is important to track the date of manufacture, or vintage, of 

products in the installed base because the energy efficiency and price of products sold 

changes over time. DOE used the following inputs to calculate the national inventory for 

the determination analysis: 

• Start-Year Shipments 

The values for start-year shipments by representative product class, estimated 

in chapter 9 of the draft technical report. 

• Shipment Growth Rate 

The values for shipment growth rate by representative product class, estimated 

in chapter 9 of the draft technical report. 

• Lifetime by Representative Product Class 

The values for lifetime by product class, drawn from chapter 8 of the draft 

technical report. 

10-3
 

EERE-2008-BT-STD-0005 COMMENT 03
 

 

Table 10.1 shows how the national inventory model tracks the number of products 

by vintage in the installed base for a given year. In 2014, 100 units are sold and enter the 

installed base. In this example, the product has an average lifetime of 3 years. Therefore, 

the units sold in 2014 are retired in 2017. The shipment growth rate is 5 percent, so 105 

units are sold in 2015. These units are added to the 100 units that remain in the installed 

base from the year before. In 2015, 205 units are in the installed base. This process of 

adding to and subtracting from the installed base is carried forward throughout the 

analysis period (Figure 10.2). 

Table 10.1 Sample National Inventory Table 

Vintage Year of Analysis 

2014 2015 2016 2017 2018 2019 2020 

2014 100 100 100 - - - -

2015 - 105 105 105 - - -

2016 - - 110 110 110 - -

2017 - - - 116 116 116 -

2018 - - - - 122 122 122 

2019 - - - - - 128 128 

2020 - - - - - - 134 

Total 100 205 315 331 348 366 384 

Calculation of National Inventory 

Inputs 

Shipment Growth 

Rate 

Start Year Shipments 

Product Lifetimes 

National Inventory 

Figure 10.2. Flow Chart of the Calculation of National Inventory 

10-4
 

EERE-2008-BT-STD-0005 COMMENT 03
10.4 National Energy Savings 

Using the calculated national inventory and unit energy savings for each year of 

the analysis, DOE then calculated national energy savings by multiplying the two inputs 

together, depicted in Figure 10.3. 

Calculation of National Energy Savings 

Inputs 

National Inventory 

Unit Energy Savings 

National Energy 

Savings 

Figure 10.3. Flow Chart of the Calculation of NES 

10.5 National Net Present Value 

The national NPV of energy conservation standards for the determination analysis 

is the difference between electricity cost savings and equipment cost increases. DOE 

calculated electricity cost savings for each year by multiplying energy savings by 

forecasted electricity prices. DOE assumed that consumers paying residential electricity 

rates would receive 80 percent of the total energy savings, and that the commercial sector 

would receive the remainder. DOE calculated equipment cost increases for each year by 

taking the incremental price increase per unit (from chapter 8) between a base case and a 

standards case scenario and multiplying the difference by the national inventory. For each 

year, DOE took the difference between the savings and cost to calculate the net savings 

(if positive) or net cost (if negative). 

After calculating the net savings and costs, DOE discounted these annual values 

to the present time and summed them to obtain the national net present value, displayed 

in Figure 10.4. 

10-5
 

EERE-2008-BT-STD-0005 COMMENT 03
Calculation of Net Present Value
 

Discount Rate Net Present Value 

Figure 10.4. Flow Chart of the Calculation of NPV 

Electricity Price 

Unit Energy Savings 

National Energy
 

Savings ($)
 

National Energy
 

Savings (kWh)
 

National Inventory 

Unit Improvement
 

Cost
 

National
 

Improvement Costs
 

10-6
 

EERE-2008-BT-STD-0005 COMMENT 03
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Battery Chargers and External

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solicit comments, data, and information from

participants. DOE will also invite comment on

its preliminary analyses of battery chargers

and external power supplies as described in

the draft technical report.

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Battery Charger and External Power

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