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PRELIMINARY ANALYSIS REQUESTS FOR COMMENT

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

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

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

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

 The following list of requests for stakeholder comment is reproduced from section four of 

the Executive Summary to the Battery Charger (BC) and External Power Supply (EPS) 

Preliminary Technical Support Document (preliminary TSD). Note that these comments 

correspond to the numbered items in the preliminary analysis public meeting slides. Following 

the list are several additional requests for comment that are included in the public meeting slides 

but not in the preliminary TSD. 

1. Criteria for Identifying Charge Control in Wall Adapters 

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

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

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

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

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

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

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

of the preliminary TSD. 

2. Design Options for Battery Chargers and External Power Supplies 

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

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

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

3. Product Classes for Battery Chargers 

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

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

low energy, high voltage product class. 

4. Dissimilarities Between Low Energy, High Voltage Battery Chargers 

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

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

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

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

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

through the creation of additional product classes.
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5. Scaling Within Battery Charger Product Classes 

During interviews, some manufacturers suggested using the EPS ENERGY STAR 

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

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

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

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

6. Medium Energy, Low Voltage Representative Unit for BCs 

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

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

7. EPS Representative Units 

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

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

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

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

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

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

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

8. EPS Max-Tech Value for 2.5-Watt Representative Unit

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

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

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

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

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

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

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

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

level for 2.5W EPSs in the NOPR. 

9. Efficiency Metrics for Multiple-Voltage EPSs 

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

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

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

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

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

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

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

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

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

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

operating conditions described by a stakeholder (Microsoft, EERE‐2008‐BT‐TP‐0004 No.8 at p. 
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1-2). Overall, DOE faces the same challenge with multiple-voltage EPSs as it does with singlevoltage EPSs: products change continuously, so the test metric should be robust enough to be 

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

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

10. Representative Product Classes and Units for MADB EPSs 

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

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

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

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

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

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

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

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

analyze that unit if it cannot identify any associated applications. 

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

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

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

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

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

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

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

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

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

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

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

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

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

in light of their critical lifesaving role. 

12. Scaling for EPS Representative Units and CSLs 

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

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

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

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

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

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

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

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

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

relationships: 

• Efficiency by nameplate output power 
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• Efficiency by nameplate output voltage 

• Efficiency by output cord length 

• Cost by nameplate output power 

• Cost by output cord length 

• Markups to MSP 

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

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

its decision on which scaling relationships to develop. 

13. Cost Estimates for Product Classes not Fully Analyzed 

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

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

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

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

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

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

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

corresponding representative unit. DOE invites comment on these approaches. 

14. Market Data 

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

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

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

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

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

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

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

representative unit. 

15. Product Lifetimes 

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

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

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

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

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

unit. 

16. Estimated Markups and Incremental Markup Assumptions 

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

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

comment on the accuracy of its estimated markups and specifically seeks comment on the 
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assumptions and methods used to calculate markups applied to baseline product costs (baseline 

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

17. Sensitivity Analysis Methodology and Results 

DOE conducted sensitivity analyses to quantify the relationship between certain critical 

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

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

seeks comment on the sensitivity analysis results and methodology. 

18. Use in the Commercial Sector 

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

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

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

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

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

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

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

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

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

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

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

savings estimations. DOE seeks comments on this proposal. 

19. Prospects for Substitution in Response to Standards

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

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

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

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

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

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

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

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

standards. 

20. Usage Profiles 

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

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

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

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

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

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

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

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

comment on all of these usage profiles. 

21. Selecting Battery Charger Usage Profiles for Use in Determining Compliance with 

Standards 

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

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

should be determined. 

22. Shipment Trends 

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

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

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

assumption. 

23. Base Case Efficiency Distributions 

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

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

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

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

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

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

forecast for use in calculating NES and NPV. 

24. Quantifying Non-Consumer Benefits 

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

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

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

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

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

25. Impact on Manufacturers 

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

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

on manufacturers presented in chapter 12. 

26. Cumulative Regulatory Burdens 

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

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

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

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

contribute to manufacturers’ cumulative regulatory burden. DOE also requests information on 
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the cost of low- and high-efficiency BCs and EPSs that are expected to be compliant with these 

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

27. Valuing Airborne Emission Reductions 

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

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

BCs and EPSs are to reduce power plant emissions resulting from reduced consumption of 

electricity. DOE will assess these environmental effects by using NEMS-BT to provide key 

inputs to its analysis. The portion of the environmental assessment that will be produced by 

NEMS-BT considers carbon dioxide (CO2), sulfur dioxide (SO2), nitrogen oxides (NOX), and 

mercury (Hg). DOE also plans to monetize the emission reductions due to standards consistent 

with methods used in recent DOE standards rulemakings pertaining to commercial clothes 

washers and other consumer products and commercial equipment. For example, in the case of 

CO2, the most recent interagency estimates of the potential global benefits resulting from 

reduced CO2 emissions in 2010 were $4.7, $21.4, $35.1, and $64.9 per metric ton in 2007 

dollars. DOE invites comment on possible approaches to monetizing the emission reductions 

expected to result from energy conservation standards. 

ADDITIONAL REQUESTS FOR COMMENT

 In addition to the above issues, which were identified in the preliminary TSD, DOE also 

seeks comment on the following issues. 

A. MADB EPS Shipments

DOE seeks comment on the percent of wall adapters for MADB applications that lack 

charge control and thus are EPSs under the ENERGY STAR criteria. 

 

B. EPS Representative Units and CSLs

DOE seeks comment on the appropriateness of its EPS representative units and CSLs. In 

particular, DOE requests comment on whether 2.5W EPSs may be able to achieve a maxtech efficiency higher than 73.9 percent. 

 

C. Aggregation Methodology

As detailed in the TSD, manufacturers’ data was aggregated into a three-dimensional 

equation. DOE seeks comment on this aggregation methodology. 

D. Scaling CSLs within BC Product Classes

DOE seeks comment on suggested methodologies to scale CSLs from representative 

units to all units within each BC product class.