15-i

CHAPTER 15. EMISSIONS ANALYSIS

TABLE OF CONTENTS

15.1 INTRODUCTION ......................................................................................................... 15-1

15.2 AIR EMISSIONS DESCRIPTIONS AND REGULATION......................................... 15-1

15.3 GLOBAL CLIMATE CHANGE................................................................................... 15-4

15.4 ANALYTICAL METHODS FOR AIR EMISSIONS................................................... 15-6

15.5 EFFECTS ON POWER PLANT EMISSIONS ............................................................. 15-7

15.6 EFFECTS ON UPSTREAM FUEL-CYCLE EMISSIONS .......................................... 15-9

15.7 SUMMARY OF EMISSIONS IMPACTS .................................................................. 15-10

LIST OF TABLES

Table 15.5.1 Power Sector Emissions Forecast from AEO2010 Reference Case................... 15-7

Table 15.5.2 Power Sector Emissions Impacts Forecasts for Microwave Oven Standby 

Power TSLs........................................................................................................ 15-8

Table 15.6.1 Estimated Upstream Emissions of Air Pollutants as a Percentage of Direct 

Power Plant Combustion Emissions.................................................................. 15-9

Table 15.7.1 Cumulative Emissions Reductions Under Microwave Oven Standby 

Power TSLs*.................................................................................................... 15-10
15-1

CHAPTER 15. EMISSIONS ANALYSIS

15.1 INTRODUCTION

This chapter describes potential changes to emissions of carbon dioxide (CO2) and three 

air pollutants that may result from amended energy conservation standards for standby power in 

microwave ovens.

15.2 AIR EMISSIONS DESCRIPTIONS AND REGULATION

This analysis considers three air pollutants: sulfur dioxide (SO2), nitrogen oxides (NOX), 

and mercury (Hg). An air pollutant is any substance in the air that can cause harm to humans or 

the environment. Pollutants may take the form of solid particles (i.e., particulates or particulate 

matter), liquid droplets, or gases.a DOE’s analysis also considers carbon dioxide (CO2), which is 

of interest because of its classification as a greenhouse gas (GHG). 

Sulfur Dioxide. Sulfur dioxide, or SO2, belongs to the family of sulfur oxide gases 

(SOx). These gases dissolve easily in water. Sulfur is prevalent in all raw materials, including 

crude oil, coal, and ore that contains common metals like aluminum, copper, zinc, lead, and iron. 

SOx gases are formed when fuel containing sulfur, such as coal and oil, is burned, and when 

gasoline is extracted from oil, or metals are extracted from ore. SO2 dissolves in water vapor to 

form acid, and interacts with other gases and particles in the air to form sulfates and other 

products that can be harmful to people and their environment.1

Nitrogen Oxides. Nitrogen oxides, or NOX, is the generic term for a group of highly 

reactive gases, all of which contain nitrogen and oxygen in varying amounts. Many of the 

nitrogen oxides are colorless and odorless. However, one common pollutant, nitrogen dioxide 

(NO2), along with particles in the air can often be seen as a reddish-brown layer over many urban 

areas. NO2 is the specific form of NOX reported in this document. NOX is one of the main 

ingredients involved in the formation of ground-level ozone, which can trigger serious 

respiratory problems. It can contribute to the formation of acid rain, and can impair visibility in 

areas such as national parks. NOX also contributes to the formation of fine particles that can 

impair human health.2

Nitrogen oxides form when fossil fuel is burned at high temperatures, as in a combustion 

process. The primary manmade sources of NOX are motor vehicles, electric utilities, and other 

industrial, commercial, and residential sources that burn fossil fuels. NOX can also be formed 

naturally. Electric utilities account for about 22 percent of NOX emissions in the United States.2

Mercury. Coal-fired power plants emit mercury (Hg) found in coal during the burning 

process. While coal-fired power plants are the largest remaining source of human-generated Hg 

emissions in the United States, they contribute very little to the global Hg pool or to 

contamination of U.S. waters.3

 

a More information on air pollution characteristics and regulations is available on the U.S. Environment Protection 

Agent (EPA)’s website at www.epa.gov.

U.S. coal-fired power plants emit Hg in three different forms: 
15-2

oxidized Hg (likely to deposit within the United States); elemental Hg, which can travel 

thousands of miles before depositing to land and water; and Hg that is in particulate form. 

Atmospheric Hg is then deposited on land, lakes, rivers, and estuaries through rain, snow, and 

dry deposition. Once there, it can transform into methylmercury and accumulate in fish tissue 

through bioaccumulation. 

Americans are exposed to methylmercury primarily by eating contaminated fish. Because 

the developing fetus is the most sensitive to the toxic effects of methylmercury, women of 

childbearing age are regarded as the population of greatest concern. Children exposed to 

methylmercury before birth may be at increased risk of poor performance on neurobehavioral 

tasks, such as those measuring attention, fine motor function, language skills, visual-spatial

abilities, and verbal memory.4

Carbon Dioxide. Carbon dioxide (CO2) is of interest because of its classification as a 

greenhouse gas (GHG). GHGs trap the sun’s radiation inside the Earth’s atmosphere and either 

occur naturally in the atmosphere or result from human activities. Naturally occurring GHGs 

include water vapor, CO2, methane (CH4), nitrous oxide (N2O), and ozone (O3). Human 

activities, however, add to the levels of most of these naturally occurring gases. For example, 

CO2 is emitted to the atmosphere when solid waste, fossil fuels (oil, natural gas, and coal), wood, 

and wood products are burned. In 2007, over 90 percent of anthropogenic (i.e., human-made) 

CO2 emissions resulted from burning fossil fuels.5

Concentrations of CO2 in the atmosphere are naturally regulated by numerous processes, 

collectively known as the “carbon cycle.” The movement of carbon between the atmosphere and 

the land and oceans is dominated by natural processes, such as plant photosynthesis. While these 

natural processes can absorb some of the anthropogenic CO2 emissions produced each year, 

billions of metric tons are added to the atmosphere annually. In the United States, in 2007, CO2

emissions from electricity generation accounted for 39 percent of total U.S. GHG emissions.5

Particulate Matter. Particulate matter (PM), also known as particle pollution, is a 

complex mixture of extremely small particles and liquid droplets. Particle pollution is made up 

of a number of components, including acids (such as nitrates and sulfates), organic chemicals, 

metals, and soil or dust particles.

PM impacts are of concern due to human exposures that can impact health. Particle 

pollution - especially fine particles - contains microscopic solids or liquid droplets that are so 

small that they can get deep into the lungs and cause serious health problems. Numerous 

scientific studies have linked particle pollution exposure to a variety of problems, including: 

increased respiratory symptoms, such as irritation of the airways, coughing, or difficulty 

breathing, for example; decreased lung function; aggravated asthma; development of chronic 

bronchitis; irregular heartbeat; nonfatal heart attacks; and premature death in people with heart or 

lung disease.

Power plant emissions can have either direct or indirect impacts on PM. A portion of the 

pollutants emitted by a power plant are in the form of particulates as they leave the smoke stack. 

These are direct, or primary, PM emissions. However, the great majority of PM emissions 
15-3

associated with power plants are in the form of secondary sulfates, which are produced at a 

significant distance from power plants by complex atmospheric chemical reactions that often 

involve the gaseous (non-particulate) emissions of power plants, mainly SO2 and NOx. The 

quantity of the secondary sulfates produced is determined by a very complex set of factors 

including the atmospheric quantities of SO2 and NOx, and other atmospheric constituents and 

conditions. Because these highly complex chemical reactions produce PM comprised of 

different constituents from different sources, EPA does not distinguish direct PM emissions from 

power plants from the secondary sulfate particulates in its ambient air quality requirements, PM 

monitoring of ambient air quality, or PM emissions inventories. Further, as described below, it is 

uncertain whether efficiency standards will result in a net decrease in power plant emissions of 

SO2, and of NOx in many States, since those pollutants are now largely regulated by cap and 

trade systems. For these reasons, it is not currently possible to determine how the standards

impact either direct or indirect PM emissions.

Air Quality Regulation. The Clean Air Act Amendments of 1990 list 188 toxic air 

pollutants that EPA is required to control.6 EPA has set national air quality standards for six 

common pollutants (also referred to as “criteria” pollutants), two of which are SO2 and NOX. 

Also, the Clean Air Act Amendments of 1990 gave EPA the authority to control acidification 

and to require operators of electric power plants to reduce emissions of SO2 and NOX. Title IV of 

the 1990 amendments established a cap-and-trade program for SO2, in all 50 states and the 

District of Columbia (D.C.), intended to help control acid rain.

6 This cap-and-trade program 

serves as a model for more recent programs with similar features.

In 2005, EPA issued the Clean Air Interstate Rule (CAIR) under sections 110 and 111 of 

the Clean Air Act (40 CFR Parts 51, 96, and 97).b 70 FR 25162–25405 (May 12, 2005). CAIR 

limited emissions from 28 eastern States and D.C. by capping emissions and creating an 

allowance-based trading program. Although, CAIR was remanded to EPA by the U.S. Court of 

Appeals for the District of Columbia Circuit (D.C. Circuit), (see North Carolina v. EPA, 550 

F.3d 1176 (D.C. Cir. 2008),) it remained in effect temporarily, consistent with the D.C. Circuit’s 

earlier opinion in North Carolina v. EPA, 531 F.3d 896 (D.C. Cir. 2008). 

On July 6, 2011, EPA promulgated a replacement for CAIR, entitled “Federal 

Implementation Plans: Interstate Transport of Fine Particulate Matter and Ozone and Correction 

of SIP Approvals,” but commonly referred to as the Cross-State Air Pollution Rule or the 

Transport Rule. 76 FR 48208 (Aug. 8, 2011). On December 30, 2011, however, the D.C. Circuit 

stayed the new rules while a panel of judges reviews them, and told EPA to continue enforcing

CAIR (see EME Homer City Generation v. EPA, No. 11-1302, Order at *2 (D.C. Cir. Dec. 30, 

2011)).

On December 21, 2011, EPA announced national emissions standards for hazardous air 

pollutants (NESHAPs) for mercury and certain other pollutants emitted from coal and oil-fired 

EGUs. (http://epa.gov/mats/pdfs/20111216MATSfinal.pdf) The NESHAPs do not include a 

 

b See http://www.epa.gov/cleanairinterstaterule/.
15-4

trading program and, as such, DOE’s energy conservation standards would likely reduce Hg 

emissions.

15.3 GLOBAL CLIMATE CHANGE

Climate change has evolved into a matter of global concern because it is expected to have 

widespread, adverse effects on natural resources and systems. A growing body of evidence 

points to anthropogenic sources of greenhouse gases, such as carbon dioxide (CO2), as major 

contributors to climate change. Because this rule, if finalized, will likely decrease CO2 emission 

rates from the fossil fuel sector in the United States, the Department here examines the impacts 

and causes of climate change. 

Impacts of Climate Change on the Environment. Climate is usually defined as the 

average weather, over a period ranging from months to many years. Climate change refers to a 

change in the state of the climate, which is identifiable through changes in the mean and/or the 

variability of its properties (e.g., temperature or precipitation) over an extended period, typically 

decades or longer. 

The World Meteorological Organization and United Nations Environment Programme 

(UNEP) established the Intergovernmental Panel on Climate Change (IPCC) to provide an

objective source of information about climate change. According to the IPCC Fourth Assessment 

Report (IPCC Report), published in 2007, climate change is consistent with observed changes to 

the world’s natural systems; the IPCC expects these changes to continue.

7

Changes that are consistent with warming include warming of the world’s oceans to a 

depth of 3000 meters; global average sea level rise at an average rate of 1.8 mm per year from 

1961 to 2003; loss of annual average Arctic sea ice at a rate of 2.7 percent per decade, changes in 

wind patterns that affect extra-tropical storm tracks and temperature patterns, increases in intense 

precipitation in some parts of the world, as well as increased drought and more frequent heat 

waves in many locations worldwide, and numerous ecological changes.

8

Looking forward, the IPCC describes continued global warming of about 0.2 °C per 

decade for the next two decades under a wide range of emission scenarios for carbon dioxide 

(CO2), other greenhouse gases (GHGs), and aerosols. After that period, the rate of increase is 

less certain. The IPCC Report describes increases in average global temperatures of about 1.1 °C 

to 6.4 °C at the end of the century relative to today. These increases vary depending on the model 

and emissions scenarios.

8

The IPCC Report describes incremental impacts associated with the rise in temperature. 

At ranges of incremental increases to the global average temperature, IPCC reports, with either 

high or very high confidence, that there is likely to be an increasing degree of impacts such as 

coral reef bleaching, loss of wildlife habitat, loss to specific ecosystems, and negative yield 

impacts for major cereal crops in the tropics, but also projects that there likely will be some 

beneficial impacts on crop yields in temperate regions. 
15-5

Causes of Climate Change. The IPCC Report states that the world has warmed by about 

0.74 °C in the last 100 years. The IPCC Report finds that most of the temperature increase since 

the mid-20th century is very likely due to the increase in anthropogenic concentrations of CO2

and other long-lived greenhouse gases such as methane and nitrous oxide in the atmosphere, 

rather than from natural causes. 

Increasing the CO2 concentration partially blocks the earth’s re-radiation of captured 

solar energy in the infrared band, inhibits the radiant cooling of the earth, and thereby alters the 

energy balance of the planet, which gradually increases its average temperature. The IPCC 

Report estimates that currently, CO2 makes up about 77 percent of the total CO2-equivalentc

global warming potential in GHGs emitted from human activities, with the vast majority (74 

percent) of the CO2 attributable to fossil fuel use.8 For the future, the IPCC Report describes a 

wide range of GHG emissions scenarios, but under each scenario CO2 would continue to 

comprise above 70 percent of the total global warming potential.9

Stabilization of CO2 Concentrations. Unlike many traditional air pollutants, CO2 mixes 

thoroughly in the entire atmosphere and is long-lived. The residence time of CO2 in the 

atmosphere is long compared to the emission processes. Therefore, the global cumulative 

emissions of CO2 over long periods determine CO2 concentrations because it takes hundreds of 

years for natural processes to remove the CO2. Globally, 49 billion metric tons of CO2 –

equivalent of anthropogenic (man-made) greenhouse gases are emitted every year.d Of this 

annual total, fossil fuels contribute about 29 billion metric tons of CO2.

9

Researchers have focused on considering atmospheric CO2 concentrations that likely will 

result in some level of global climate stabilization, and the emission rates associated with 

achieving the “stabilizing” concentrations by particular dates. They associate these stabilized 

CO2 concentrations with temperature increases that plateau in a defined range. For example, at 

the low end, the IPCC Report scenarios target CO2 stabilized concentrations range between 350 

ppm and 400 ppm (essentially today’s value)—because of climate inertia, concentrations in this 

low-end range would still result in temperatures projected to increase 2.0 °C to 2.4 °C above preindustrial levelse

 c GHGs differ in their warming influence (radiative forcing) on a global climate system due to their different 

radiative properties and lifetimes in the atmosphere. These warming influences may be expressed through a common 

metric based on the radiative forcing of CO2, i.e., CO2-equivalent. CO2 equivalent emission is the amount of CO2

emission that would cause the same- time integrated radiative forcing, over a given time horizon, as an emitted 

amount of other long- lived GHG or mixture of GHGs.

(about 1.3 °C to 1.7 °C above today’s levels). To achieve concentrations 

between 350 ppm to 400 ppm, the IPCC scenarios present that there would have to be a rapid 

downward trend in total annual global emissions of greenhouse gases to levels that are 50 to 85 

percent below today’s annual emission rates by no later than 2050. Since it is assumed that there 

would continue to be growth in global population and substantial increases in economic 

production, the scenarios identify required reductions in greenhouse gas emissions intensity 

(emissions per unit of output) of more than 90 percent. However, even at these rates, the 

d Other non-fossil fuel contributors include CO2 emissions from deforestation and decay from agriculture biomass; 

agricultural and industrial emissions of methane; and emissions of nitrous oxide and fluorocarbons.

e IPCC Working Group 3 Table TS 2
15-6

scenarios describe some warming and some climate change is projected due to already 

accumulated CO2 and GHGs in the atmosphere.10

It is difficult to correlate specific emission rates with atmospheric concentrations of CO2 

and specific atmospheric concentrations with future temperatures because the IPCC Report 

describes a clear lag in the climate system between any given concentration of CO2 (even if 

maintained for long periods) and the subsequent average worldwide and regional temperature, 

precipitation, and extreme weather regimes. For example, a major determinant of climate 

response is “equilibrium climate sensitivity”, a measure of the climate system response to 

sustained radioactive forcing. It is defined as the global average surface warming following a 

doubling of carbon dioxide concentrations. The IPCC Report describes its estimated, numeric 

value as about 3 °C, but the likely range of that value is 2 °C to 4.5 °C, with cloud feedbacks the 

largest source of uncertainty. Further, as illustrated above, the IPCC Report scenarios for 

stabilization rates are presented in terms of a range of concentrations, which then correlates to a 

range of temperature changes. Thus, climate sensitivity is a key uncertainty for CO2 mitigation 

scenarios that aim to meet specific temperature levels. 

15.4 ANALYTICAL METHODS FOR AIR EMISSIONS 

For each of the considered TSLs, DOE calculated total power-sector emissions based on 

output from the NEMS-BT model (see chapter 14 for description of the model).

Coal-fired electric generation is the single largest source of electricity in the United 

States. Because the mix of coals used significantly affects the emissions produced, the model 

includes a detailed representation of coal supply. The model considers the rank of the coal as 

well as the sulfur contents of the fuel used when determining optimal dispatch.

Within the NEMS-BT model, planning options for achieving emissions restrictions in the 

Clean Air Act Amendments include installing pollution control equipment on existing power 

plants and building new power plants with low emission rates. These methods for reducing 

emission are compared to dispatching options such as fuel switching and allowance trading. 

Environmental regulations also affect capacity expansion decisions. For instance, new plants are 

not allocated SO2 emissions allowances according to the Clean Air Act Amendments. 

Consequently, the decision to build a particular capacity type must consider the cost (if any) of 

obtaining sufficient allowances. This could involve purchasing allowances or over-complying at 

an existing unit.

For this analysis, DOE used the version of NEMS-BT based on AEO 2010, which 

assumes the implementation of CAIR. Thus, DOE’s analysis assumes the presence of nationwide 

emission caps on SO2 and caps on NOX emissions in the 28 States covered by CAIR. 

SO2 emissions from affected Electric Generating Units (EGUs) are subject to nationwide 

and regional emissions cap and trading programs, which create uncertainty about the impact of 

energy efficiency standards on SO2 emissions. The attainment of emissions caps is typically 
15-7

flexible among EGUs and is enforced through the use of emissions allowances and tradable 

permits. Under existing EPA regulations, any excess SO2 emissions allowances resulting from 

the lower electricity demand caused by the imposition of an efficiency standard could be used to 

permit offsetting increases in SO2 emissions by any regulated EGU. However, if the standard 

resulted in a permanent increase in the quantity of unused emissions allowances, there would be 

an overall reduction in SO2 emissions from the standards. While there remains some uncertainty 

about the ultimate effects of efficiency standards on SO2 emissions covered by the existing cap 

and trade system, the NEMS-BT model that DOE uses to forecast emissions reductions currently 

indicates that no physical reductions in power sector emissions would occur for SO2.

f

The CAIR established a cap on NOx emissions in 28 eastern states and the District of 

Columbia. All these States and D.C. have elected to reduce their NOx emissions by participating 

in cap-and-trade programs for EGUs. Therefore, energy conservation standards may have little 

or no physical effect on these emissions in the 28 eastern States and the D.C. for the same 

reasons that they may have little or no physical effect on SO2 emissions. 

DOE estimated mercury emissions reductions using NEMS-BT based on AEO2010, 

which does not incorporate the NESHAPs. DOE expects that future versions of the NEMS-BT 

model will reflect the implementation of the NESHAPs.

As noted in chapter 14, NEMS-BT model forecasts end in year 2035. Rather than 

extrapolate beyond this year, DOE assumes that emissions impacts beyond 2035 are equal to the 

impacts in 2035.

15.5 EFFECTS ON POWER PLANT EMISSIONS

Table 15.5.1 shows AEO2010 reference case power plant emissions in selected years. 

The Reference Case emissions are the emissions shown by the NEMS-BT model to result if none 

of the TSLs are promulgated (the base case). 

Table 15.5.1 Power Sector Emissions Forecast from AEO2010 Reference Case

NEMS-BT Results 2010 2015 2020 2025 2030 2035

CO2 (million metric tons) 2,218 2,278 2,341 2,421 2,534 2,636

NOX (million tons) 2.24 2.06 2.02 2.03 2.06 2.07

Hg (tons) 40.6 30.6 30.1 30.0 30.2 30.3

 

f In contrast to the modeling forecasts of NEMS-BT that SO2 emissions will remain at the cap, during the years 2007 

and 2008, SO2 emissions were below the trading cap. This raises the possibility that standards could cause some 

reduction in SO2 emissions. However, because DOE does not have a method to predict when emissions will be 

below the trading cap, it continues to reply on NEMS-BT and thus does not estimate SO2 emissions reductions at 

this time.
15-8

Table 15.5.2 shows the estimated changes in power plant emissions by TSL for standby 

power in microwave ovens. The tables display changes in CO2, NOx, and Hg emissions in 

selected years for each of the TSLs. “Mt” refers to “million metric tons.”

Table 15.5.2 Power Sector Emissions Impacts Forecasts for Microwave Oven Standby 

Power TSLs

NEMS-BT Results* Difference from AEO2010 Reference Case

Total

2010 2015 2020 2025 2030 2035 2040 2043 2014-2043

Standard Level 1

CO2 (Mt/yr) 0.04 0.02 -0.42 -0.72 -0.67 -0.60 -0.60 -0.60 -15.8

NOx (1,000 tons/yr) 0.04 0.02 -0.36 -0.61 -0.55 -0.47 -0.47 -0.47 -12.9

Hg (ton/yr) 0.000 0.000 -0.003 -0.003 -0.004 -0.003 -0.003 -0.003 -0.074

Sandard Level 2

CO2 (Mt/yr) 0.06 0.03 -0.61 -1.04 -0.97 -0.87 -0.87 -0.87 -22.9

NOx (1,000 tons/yr) 0.06 0.03 -0.52 -0.87 -0.79 -0.68 -0.68 -0.68 -18.6

Hg (ton/yr) 0.000 0.001 -0.004 -0.004 -0.005 -0.004 -0.004 -0.004 -0.107

Standard Level 3

CO2 (Mt/yr) 0.09 0.05 -0.84 -1.43 -1.34 -1.19 -1.19 -1.19 -31.5

NOx (1,000 tons/yr) 0.09 0.04 -0.72 -1.20 -1.09 -0.94 -0.94 -0.94 -25.6

Hg (ton/yr) 0.000 0.001 -0.006 -0.006 -0.007 -0.005 -0.005 -0.005 -0.147

Standard Level 4

CO2 (Mt/yr) 0.14 0.07 -1.29 -2.20 -2.06 -1.84 -1.84 -1.84 -48.5

NOx (1,000 tons/yr) 0.14 0.07 -1.11 -1.85 -1.67 -1.44 -1.44 -1.44 -39.4

Hg (ton/yr) 0.000 0.001 -0.009 -0.009 -0.011 -0.008 -0.008 -0.008 -0.226

*CO2 results are in metric tons, NOX and Hg results are in short tons.

Extrapolation
15-9

15.6 EFFECTS ON UPSTREAM FUEL-CYCLE EMISSIONS

Upstream fuel-cycle emissions refer to the emissions associated with the amount of 

energy used in the upstream production and downstream consumption of electricity, including 

energy used at the power plant.17 Upstream processes include the mining of coal or extraction of 

natural gas, physical preparatory and cleaning processes, and transportation to the power plant. 

The NEMS-BT does a thorough accounting of emissions at the power plant due to downstream 

energy consumption, but does not account for upstream emissions (i.e., emissions from energy 

losses during coal and natural gas production). Thus, this analysis reports only power plant 

emissions.

However, previous DOE environmental assessment documents have developed 

approximate estimates of effects on upstream fuel-cycle emissions. These emissions factors 

provide the reader with a sense of the possible magnitude of upstream effects. These upstream 

emissions would be in addition to emissions from direct combustion. 

Relative to the entire fuel cycle, estimates based on the work of Dr. Mark DeLuchi, and 

reported in earlier DOE environmental assessment documents, find that an amount 

approximately equal to eight percent, by mass, of emissions (including SO2) from coal 

production are due to mining, preparation that includes cleaning the coal, and transportation from 

the mine to the power plant.18 Transportation emissions include emissions from the fuel used by 

the mode of transportation that moves the coal from the mine to the power plant. In addition, 

based on Dr. DeLuchi’s work, DOE estimated that an amount equal to approximately 14 percent 

of emissions from natural gas production result from upstream processes. 

Emission factor estimates and corresponding percentages of contributions of upstream 

emissions from coal and natural gas production, relative to power plant emissions, are shown in 

Table 15.6.1 for CO2 and NOX. The percentages provide a means to estimate upstream emission 

savings based on changes in emissions from power plants. This approach does not address Hg 

emissions.

Table 15.6.1 Estimated Upstream Emissions of Air Pollutants as a Percentage of 

Direct Power Plant Combustion Emissions

Pollutant

Percent of Coal

Combustion Emissions

Percent of Natural Gas

Combustion Emissions

CO2 2.7 11.9

NOX 5.8 40
15-10

15.7 SUMMARY OF EMISSIONS IMPACTS

Table 15.7.1 summarizes the estimated emissions impacts for each of the TSLs for

standby power in microwave ovens. It shows cumulative changes in emissions for CO2, NOX, 

and Hg for 2014 through 2043 for each of the TSLs. Cumulative CO2, NOX, and Hg emissions 

are reduced compared to the Reference case for all TSLs. For comparison, the cumulative power 

sector emissions in the AEO2010 Reference case, over the period 2014 through 2043, are 74,571 

Mt for CO2, 61,625 kt for NOx, and 917 tons for Hg.

Upstream fuel cycle emission of CO2 and NOX are described but not quantified in section 

15.2.6. The text describes potential reductions in fuel cycle emissions as percentage of decreases 

in power plant emissions. This approach suggests that upstream fuel cycle emissions would 

decrease and provides a sense for the magnitude of effects; however DOE does not report actual 

estimates of the effects. 

For subgroups of low-income and senior consumers that purchase microwave ovens, 

DOE determined that the average LCC impact of the standards is similar to that for the full 

sample of consumers. Therefore, DOE concludes that the proposed standards would have no 

significant adverse socioeconomic impact.

No impacts are anticipated in the areas of environmental justice, wetlands, endangered 

and threatened species, and cultural resources; or noise and aesthetics.

Table 15.7.1 Cumulative Emissions Reductions Under Microwave Oven Standby 

Power TSLs*

TSL 1 TSL 2 TSL 3 TSL 4

Microwave Oven Standby Power

 CO2 (Mt)

 NOX (1,000 tons)

 Hg (ton)

15.8

12.9

0.074

22.9

18.6

0.107

31.5

25.6

0.147

48.5

39.4

0.226

*CO2 results are in million metric tons; NOX and Hg results are in short tons.
15-11

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3 U.S. Environmental Protection Agency, Mercury, 2011. http://www.epa.gov/mercury/

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Argonne, IL. Report No. ANL/ESD/TM-22-Vol.2.