ENVIRONMENTAL ASSESSMENT FOR PROPOSED ENERGY CONSERVATION 

STANDARDS FOR RESIDENTIAL DISHWASHERS, DEHUMIDIFIERS, AND 

COOKING PRODUCTS, AND COMMERCIAL CLOTHES WASHERS 

TABLE OF CONTENTS 

1.0 INTRODUCTION ........................................................................................................EA-1

2.0 METHODOLOGY .......................................................................................................EA-2

3.0 RESULTS .....................................................................................................................EA-3

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EE-2006-STD-0127 COMMENT 39.2
ENVIRONMENTAL ASSESSMENT FOR PROPOSED ENERGY CONSERVATION 

STANDARDS FOR RESIDENTIAL DISHWASHERS, DEHUMIDIFIERS, COOKING

PRODUCTS, AND COMMERCIAL CLOTHES WASHERS 

1.0 INTRODUCTION 

The Department of Energy (DOE) will conduct an environmental assessment as part of 

the notice of proposed rulemaking. DOE will assess the impacts of proposed energy 

conservation standards for residential dishwashers, dehumidifiers, and cooking products and 

commercial clothes washers on certain environmental indicators using a variant of the U.S. 

DOE/Energy Information Administration (EIA)’s National Energy Modeling System (NEMS).a 

EIA uses NEMS to produce the Annual Energy Outlook (AEO). 1

 DOE will use a variant known 

as NEMS-BT to provide key inputs to the analysis, based on the 2007 version of the AEO 

(AEO2007). Results of the environmental assessment will be similar to those provided in 

AEO2007. 

DOE intends the environmental assessment to provide emissions results to policymakers 

and other stakeholders, and to fulfill requirements that the environmental effects of all new 

Federal rules be properly quantified and considered. The environmental assessment considers 

three pollutants— sulfur dioxide (SO2), nitrogen oxides (NOx), and mercury—as well as carbon 

emissions. The only form of carbon emissions tracked by NEMS-BT is carbon dioxide (CO2), so 

the carbon discussed in this report is only in the form of CO2. For each of the trial standard 

levels, DOE will calculate total emissions using NEMS-BT, using additional, external analysis as 

needed. 

Although DOE plans to consider only SO2, NOx, mercury, and CO2 in its environmental 

assessment, there are other air pollutants which are of concern. Specifically, the Clean Air Act 

requires the Environmental Protection Agency (EPA) to set National Ambient Air Quality 

Standards for the following six common air pollutants, also know as “criteria pollutants”: (1) 

ozone, (2) particulate matter (PM), (3) carbon monoxide (CO), (4) nitrogen dioxide, (5) SO2, and 

(6) lead.2

 EPA recently added to this list mercury. But none of the “criteria pollutants” not 

already considered (i.e., ozone, PM, CO, and lead) are driven significantly by either electric 

utility power plants or fuel-fired appliances. Therefore, DOE does not intend on addressing them 

in the environmental assessment. In the case of ozone and particulate matter, other pollutants are 

precursors to their formation and atmospheric conditions are the driver behind their formation. 

Also, SO2 and NOx are the primary precursors to ozone and PM, respectively, and will already 

be addressed by the environmental assessment. In the case of CO, electric utilities and fuel-fired 

appliances are not significant sources. For electric power plants, almost all carbon emissions 

come out in the form of CO2 as the combustion process is lean enough not to yield CO in 

significant amounts. For fuel-fired appliances, proper appliance maintenance, installation, and 

a For more information on NEMS, please refer to the U.S. Department of Energy, Energy Information 

Administration documentation. A useful summary is National Energy Modeling System: An Overview 2000, 

DOE/EIA-0581(2000), March 2000. EIA approves use of the name NEMS to describe only an official version of 

the model without any modification to code or data. Because this analysis entails some minor code modifications 

and the model is run under various policy scenarios that are variations on EIA assumptions, DOE refers to the model 

as NEMS-BT (BT is DOE’s Building Technologies Program). NEMS-BT was previously called NEMS-BRS. 

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use can prevents dangerous levels of CO. A well-designed and properly functioning heating or 

cooking appliance should not produce toxic or lethal levels of CO, as, most often, CO poisoning 

occurs in the home as a result of malfunctioning appliances. Finally, with regard to lead, the ban 

on the use of leaded gasoline has resulted in a dramatic decrease in lead emissions since the mid 

1970s. Now industrial processes (not electric utilities), particularly primary and secondary lead 

smelters and battery manufacturers, are responsible for most of lead emissions and all violations 

of the lead air quality standards. 

2.0 METHODOLOGY 

DOE will conduct the environmental assessment as a policy deviation from the 

AEO2007, using the same basic set of assumptions. For example, the emissions characteristics 

of an electricity generating plant will be exactly those used in AEO2007. The NEMS reference 

case and alternative growth scenarios are as described in the utility impact analysis (see Chapter 

13 of the technical support document). 

NEMS-BT tracks carbon emissions using a detailed carbon module; this approach 

provides good results because of its broad coverage of all sectors and inclusion of interactive 

effects. Past experience with carbon results from NEMS suggests that the NEMS-generated 

emissions estimates are somewhat lower than estimates based on simple average factors. One of 

the reasons for this divergence is that NEMS tends to predict that conservation displaces 

renewable generating capacity in the later years of its forecast. On the whole, NEMS-BT 

provides carbon emissions results of reasonable accuracy, at a level consistent with other 

published Federal results. 

The NEMS-BT model reports the two airborne pollutant emissions that DOE has reported 

in past analyses, SO2 and NOx. The Clean Air Act Amendments of 1990 set an SO2 emissions 

cap on all power generation.3 The attainment of this target, however, is flexible among 

generators through the use of emissions allowances and tradable permits. The NEMS-BT model 

includes a module for SO2 allowance trading and delivers a forecast of SO2 allowance prices. 

Accurate simulation of SO2 trading tends to imply that physical emissions effects will be zero, as 

long as emissions are at the ceiling. There is an SO2 benefit from conservation in the form of a 

lower allowance price but, since the impact of any one standard on the allowance price is likely 

small and highly uncertain, DOE does not plan to monetize the SO2 benefit. 

NEMS-BT also has an algorithm for estimating NOX emissions from power generation. 

The impact of these emissions, however, will be affected by the Clean Air Interstate Rule 

(CAIR), which the U.S. Environmental Protection Agency (EPA) issued on May 12, 2005.4 

CAIR will permanently cap emissions of NOx in 28 eastern States and the District of Columbia. 

As with SO2 emissions, a cap on NOX emissions means that equipment efficiency standards may 

have no physical effect on these emissions. When NOx emissions are subject to emissions caps, 

DOE’s emissions reduction estimate corresponds to incremental changes in the prices of 

emissions allowances in cap-and-trade emissions markets rather than physical emissions 

reductions. Therefore, while the emissions cap may mean that physical emissions reductions 

will not result from standards, standards could produce an environmental-related economic 

benefit in the form of lower prices for emissions allowance credits. However, as with SO2 

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allowance prices, DOE does not plan to monetize this benefit because the impact on the NOx 

allowance price from any single energy conservation standard is likely small and highly 

uncertain. 

While NEMS-BT contains provisions for estimating emissions of CO2, NOx, and SO2 

from power generation, it does not estimate emissions from gas appliances (e.g., gas water 

heaters used to heat water for commercial clothes washers and residential dishwashers, and gas 

cooking products). Therefore, DOE plans to conduct an analysis that includes separate estimates 

of the effect of energy conservation standards on CO2, NOx, and SO2 emissions from gas 

appliances, based on simple emissions factors derived from the literature.5 Although household 

NOx and SO2 emissions savings will be small, DOE will report them because the emissions caps 

do not apply to the residential sector. 

With regard to mercury emissions, NEMS has an algorithm for estimating these 

emissions from power generation. However, the impact on mercury emissions will be affected 

by the Clean Air Mercury Rule (CAMR), which the EPA issued on May 18, 2005.6 CAMR will 

permanently cap emissions of mercury for new and existing coal-fired plants in all States. As 

with SO2 and NOx emissions, a cap on mercury emissions means that equipment efficiency 

standards may have no physical effect on these emissions. When mercury emissions are subject 

to emissions caps, DOE’s emissions reduction estimate corresponds to incremental changes in 

the prices of emissions allowances in cap-and-trade emissions markets rather than physical 

emissions reductions. Therefore, while the emissions cap may mean that physical emissions 

reductions will not result from standards, standards could produce an environmental-related 

economic benefit in the form of lower prices for mercury emissions allowance credits. However, 

as with SO2 and NOx allowance prices, DOE does not plan to monetize this benefit because the 

impact on the mercury allowance price from any single energy conservation standard is likely 

small and highly uncertain. 

3.0 RESULTS 

The results for the environmental assesssment are similar to a complete NEMS run, as 

published in the AEO2007. These include emissions for SO2, NOx, mercury, and CO2 in fiveyear forecasted increments, extrapolated to the year 2042. DOE will report the outcome of the 

analysis for each trial standard level as a deviation from the AEO2007 reference case results. 

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REFERENCES 

1 U.S. Department of Energy-Energy Information Administration. Annual Energy Outlook 

2007 with Projections to 2030, February, 2007. Washington, DC. DOE/EIA-0383(2007). 

2 U.S. Environmental Protection Agency. Six Common Air Pollutants. Washington, DC. 

<http://www.epa.gov/air/urbanair/> 

3 U.S. Environmental Protection Agency. Clean Air Act. Washington, DC. 

<http://www.epa.gov/air/caa/> 

4 U.S. Federal Register. Rule To Reduce Interstate Transport of Fine Particulate Matter and 

Ozone (Clean Air Interstate Rule); Revisions to Acid Rain Program; Revisions to the NOX 

SIP Call, Final Rule, May 12, 2005. 70 FR 25162. 

5 U.S. Environmental Protection Agency. Compilation of Air Pollutant Emission Factors, AP42, Fifth Edition, Volume I: Stationary Point and Area Sources. 1998. (Posted October) 

<http://www. epa.gov/ttn/chief/ap42.html> 

6 U.S. Federal Register. Standards of Performance for New and Existing Stationary Sources: 

Electric Utility Steam Generating Units, Final Rule, May 18, 2005. 70 FR 28606. 

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