9

- i CHAPTER 9

. E MISSIONS ANALYSIS

TABLE OF CONTENTS

9.1 INTRODUCTION

................................ ................................ ................................ ........... 9

- 1

9.2 AIR EMISSIONS DESCRI PTIONS AND REGULATIO N

................................ ........... 9

- 1

9.3 GLOBAL CLIMATE CHANG E

................................ ................................ ..................... 9

- 5

9.4 ANAL YTICAL METHODS FOR A IR EMISSIONS

................................ ..................... 9

- 8

9.5 EFFECTS ON POWER PLA NT EMISSIONS

................................ ............................. 9

- 10

9.6 EFFECTS ON UPSTREAM FUEL

- CYCLE EMISSIONS

................................ .......... 9

- 14

9.7 SUMMARY OF EMISSIONS IMPACTS

................................ ................................ .... 9

- 14

LIST OF TABLES

Table 9.3.1 Reduction in Cumulative Energy

- Related Emissions of CO 2 over the analysis period for ASHRAE Energy Conservation Standards*,**,***

............. 9

- 7

Table 9.5.1 Power Sector Emissions Forecast from AEO2011 Reference Case

................... 9

- 10

Table 9.5.2 Power Sector Emissions Impacts Forecasts for Water and Evaporative Cooled Product Efficiency Levels

................................ ................................ ..... 9

- 11

Table 9.5.3 Power Sector Emissions Impact Forecasts for VRF Water Source Heat Pump E fficiency Levels

................................ ................................ ..................... 9

- 12

Table 9.5.4 Power Sector Emissions Impact Forecasts for Computer Room Air Conditioner Efficiency Levels

................................ ................................ ........... 9

- 13

Table 9.6.1 Estimated Upstream Emissions of Air Pollutants as a Percentage of Direct

Power Plant Combustion Emissions

................................ ................................ .. 9

- 14

Table 9.7.1 Cumulative Emissions Reductions Under ASHRAE Efficiency Levels*

......... 9

- 159

- 1 CHAPTER 9. E MISSIONS ANALYSIS

9.1 INTRODUCTION

This chapter describes potential changes to emissions of carbon dioxide (CO 2 ) and three air pollutants that may result from energy conservation standards for water and evaporative ly cooled products, VRF water source heat pumps, and computer room air conditioners . The impac ts on air emissions are largely driven by changes in power plant types and quantities of electricity gener ated under each of the considered standard levels . Changes in electricity generation are described in the utili ty impact analysis in chapter 11

.

DOE analyzed the effects of its amended standard levels on the electric utility industry using

a variant of the DOE/Energy Information Administration (EIA)’s National Energy Modeling System (NEMS). a NEMS is a public domain, multi

- sectored, partial equilibrium model of the U.S. energy sector. Each year, DOE/EIA uses NEMS to produce an energy forecast for the Uni ted States, the Annual Energy Outlook (AEO) . The AEO for 2011 (AEO2011) forecasts energy supply and demand through 2035. 1 DOE used a variant of this model, referred to as NEMS

- BT, b

NEMS

- BT has several advantages that have led to its adoption as the forecasting tool in the analysis of energy conservation standards. NEMS

- BT uses a set of assumptions that are well known and fairly transparent, due to the exposure and scrutiny each AEO receives. In addition, the comprehensiveness of NEMS

- BT permits the modeling of interactions among the various energy supply and demand sectors, producing a complete picture of the effects of energy conservation

s tandards. Perhaps most importantly, NEMS

- BT can be used to estimate marginal effects, which yield a better estimate of the actual impact of energy conservation standards than considering only average effects. to account for the impacts of energy conservation standards for water and evaporative cooled products, VRF water source heat pumps, and computer room air conditioners . DOE’s analysis consists of a comparison

between model results for the AEO2011 Reference Case and for cases in which standards are in place, and applies the same basic set of assumptions as the AEO2011 . The AEO2011 reference case corresponds to medium economic growth.

9.2 AIR EMISSIONS DESCRI PTIONS AND REGULATION

This analysis considers three pollutants: sulfur dioxide (SO 2 ), nitrogen oxides (NO X ), and mercury (Hg). An air pollutant is any substance in the air that can cause harm to humans or the

a For more information on NEMS, refer to the U.S. Department of Energy, Energy Information Administration documentation. A useful summary is National Energy Modeling System: An Overview 2003 , DOE/EIA

- 0581(2003), March, 2003.

b DOE/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 DOE/EIA assumptions, DOE refers to it by the name NEMS

BT (BT is DOE’s Building Technologies Program, under whose aegis this work has been performed). NEMS

- BT was previously called NEMS

- BRS.9

- 2 environment. Pollutants may be natural or man

- made (i.e., anthropogen ic) and may take the form of solid particles (i.e., particulates or particulate matter), liquid droplets, or gases. c DOE’s analysis also considers carbon dioxide (CO 2 ).

Sulfur Dioxide. Sulfur dioxide, or SO 2 , 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 coa l and oil, is burned, and when gasoline is extracted from oil, or metals are extracted from ore. SO 2 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 p eople and their environment. 1

Nitrogen Oxides. Nitrogen oxides

, or NO X , 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 (NO 2 ), along with particles in the air can often be seen as a reddish

- brown layer over many urban

areas. NO 2 is the specific form of NO X reported in this document. NO X 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. NO X also contributes to the formation of fine particles that can

im pair human health. 2

Nitrogen oxides form when fossil fuel is burned at high temperatures, as in a combustion process. The primary manmade sources of NO X are motor vehicles, electric utilities, and other industrial, commercial, and residential sources that burn fossil fuels. NO X can also be formed naturally. Electric utilities account for about 22 percent of NO X 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 U.S. coal

- fired power plants emit Hg in three different forms: 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 i n 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 expo sed 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 methylme rcury before birth may be at increased risk of poor performance on neurobehavioral

c More informatio n on air pollution characteristics and regulations is available on the U.S. Environment Protection Agent (EPA)’s website at www.epa.gov.9

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

- spatial abilities, and verbal memory. 4

Carbon Dioxide. Carbon dioxide (CO 2 ) is not a criteria pollutant (see below), but it 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. Natur ally occurring GHGs include water vapor, CO 2 , methane (CH 4 ), nitrous oxide (N 2 O), and ozone (O 3 ). Human activities, however, add to the levels of most of these naturally occurring gases. For example, CO 2 is emitted to the atmosphere when solid waste, fossi l fuels (oil, natural gas, and coal), wood, and wood products are burned. In 2007, over 90 percent of anthropogenic (i.e., human

- made) CO 2 emissions resulted from burning fossil fuels. 5

Concentrations of CO 2 in the atmosphere are naturally regulated by n umerous 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 anthrop ogenic CO 2 emissions produced each year, billions of metric tons are added to the atmosphere annually. In the United States, in 2007, CO 2 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 t he 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 e xample; decreased lung function; aggravated asthma; development of chronic bronchitis; irregular heartbeat; nonfatal heart attacks; and premature death in people with heart or lung disease.

DOE acknowledges that particulate matter (PM) exposure can impac t human health. 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 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 SO 2 and NO

x . The quantity of the secondary sulfates produced is determined by a very complex set of factors including the atmospheric quantities of SO 2 and NO

x , 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 su lfate particulates in its ambient air quality requirements, PM monitoring of ambient air quality, or PM emissions inventories. For these reasons, it is not9

- 4 currently possible to determine how the amended standard impacts either direct or indirect PM

emissi ons. Therefore, DOE is not planning to assess the impact of these standards on PM emissions. Further, as described below , it is uncertain whether efficiency standards will result in a net decrease in power plant emissions of SO 2

, and of NO

x in many States, since those pollutants are now largely regulated by cap and trade systems.

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 SO 2 and NO X

. 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 o f SO 2 and NO X . Title IV of the 1990 amendments established a cap

- and

- trade program for SO 2 , 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 wit h 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). d 70 FR 25162

– 25405 (May 12, 2005). CAIR

limited emissions from 28 eastern S tates 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, 2010, EPA issued the Transport Rule proposal, a replacement for CAIR

. 75 FR 45210 (Aug. 2, 2010). On July 6, 2011, EPA promulgated the final Transport Rule, 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).

With respect to Hg emissions, in 2005, EPA issued the final rule entitled “Standards of Performance for New and Existing Stationary Sources: Electric Steam Generating Units,” under

sections 110 a nd 111 of the Clean Air Act (40 CFR Parts 60, 63, 72, and 75)

. 7 This rule, called the Clean Air Mercury Rule (CAMR), was closely related to the CAIR and established standards of performance for Hg emissions from new and existing coal

- fired electric utility steam generating units. The CAMR regulated Hg emissions from coal

- fired power plants. On February 8, 2008, the U.S. Court of Appeals for the District of Columbia Circuit (D.C. Circuit) issued its

decision in State of New Jersey, et al. v. Environmental Pr otection Agency

, e

d See http://www.epa.gov/cleanairinterstaterule/. in which the Court, among other actions, vacated the CAMR.

e 517 F.3d 574, 583 (D.C. Cir. 2008).9

- 5 9.3 GLOBAL CLIMATE CHANG E

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 (CO 2 ), as major contributors to climate change. Because this r ule, if finalized, will likely decrease CO 2 emission

rates from the fossil fuel sector in th e United States, the Department here examines the impacts and causes of climate change and then the potential impact of the r ule on CO 2 emissions and global warming.

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 a n 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 cl imate 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

. 8

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 (CO 2 ), other greenhouse gases (GHGs), and aerosols. After that period, the rat e 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.

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 CO 29

- 6 and other long

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

rather than from natural causes.

Increasing the CO 2 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, CO 2 makes up about 77 percent of the t otal CO 2 - equivalent f
global warming potential in GHGs emitted from human activities, with the vast majority (74 percent) of the CO 2 attributable to fossil fuel use. 9 For the future, the IPCC Report describes a wide range of GHG emissions scenarios, but und er each scenario CO 2 would continue to comprise above 70 percent of the total global warming potential. 9

Stabilization of CO 2 Concentrations. Unlike many traditional air pollutants, CO 2 mixes thoroughly in the entire atmosphere and is long

- lived. The re sidence time of CO 2 in the atmosphere is long compared to the emission processes. Therefore, the global cumulative

emissions of CO 2 over long periods determine CO 2 concentrations because it takes hundreds of years for natural processes to remove the CO 2 . G lobally, 49 billion metric tons of CO 2

– equivalent of anthropogenic (man

- made) greenhouse gases are emitted every year. g Of this annual total, fossil fuels contribute about 29 billion metric tons of CO 2

. 10

Researchers have focused on considering atmospheric CO 2 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

CO 2 concentrations with temperature increases that plateau in a defined range. For example, at the low end, the IPCC Report scenarios target CO 2 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 pre

industrial levels h (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 th at 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

scenarios desc ribe some warming and some climate change is projected due to already

accumulated CO 2 and GHGs in the atmosphere. 11

f 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 CO 2 , i.e., CO 2 - equiva lent. CO 2 equivalent emission is the amount of CO 2 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.

g Other non

- fossil fuel contributors incl ude CO 2 emissions from deforestation and decay from agriculture biomass; agricultural and industrial emissions of methane; and emissions of nitrous oxide and fluorocarbons.

h IPCC Working Group 3 Table TS 29

- 7 The Beneficial Impact of the Rule on CO 2 Emissions. It is anticipated that the Rule will reduce energy

- related CO 2 emissions, particularly those associated with energy consumption in buildings. The U.S. Energy Information Administration (EIA) reports in its 2011 Annual Energy

Outlook ( AEO2011 ) 12 that U.S. annual energy

- related emissions of CO 2 in 2009 were about 5.4 billion metric tons, of whi ch 1.2 billion tons were attributed to the residential buildings sector (including energy

- using products such as space cooling products). Most of the greenhouse gas emissions attributed to residential buildings are emitted from fossil fuel

- fired power plan ts that generate electricity used in this sector. In the AEO2011 Reference Case, EIA projected that annual energy

- related CO 2 emissions would grow from 5.4 billion metric tons in 2009 to 6.3 billion metric tons in 2035, an increase of 16 percent, while res idential emissions would grow to from 1.17 billion metric tons to 1.23 billion metric tons, an increase of 5 percent.

The estimated cumulative CO 2 emission reductions from energy conservation standard s (shown a s a range of alternative Efficiency Level s) for water and evaporatively cooled products, VRF water source heat pumps, and computer room air conditioners, during the 30

- year analysis period are indicated in Table 9 .3 .1. Estimated CO 2 emission reductions in Table 9 .3 .1 only come

from electricity ge neration (i.e., power plants)

. The estimated CO 2 emission reductions from electricity generation are calc ulated using the NEMS

- BT model

.

Table 9.3.1 Reduction in Cumulative Energy

- Related Emissions of CO 2 over the analysis period for ASHRAE Energy Conservation Standa rds *,**,***
Efficiency Levels

Level 1 Level 2 Level 3 Level 4 Level 5

Million Metric Tons

Water and Evaporative Cooled

Products 0.099 0.096 0.253 0.363 0.371

VRF Water Source Heat Pumps 0.000 0.054 0.823 1.96 3.58

Computer Room Air

Conditioners 0.177 2.14 8.06 18.7 31.1

Total 0.276 2.29 9.13 21.1 35.1

Percent of Total Cumulative Emissions Reduction compared

with the AEO201 1 Reference

Case in 2014

- 2043 0.00 0.00 0.01 0.03 0.05

*The analysis period for Water and Evaporative cooled products runs from 2013 through 2043

**The analysis period for VRF water source heat pumps runs from 2013 through 2042

***The analysis period Computer Room Air Conditioners runs from 2012 through 2042

The Incremental Impact of the Rule on Climate Change. It is difficult to correlate specific emission rates with atmospheric concentrations of CO 2 and specific atmospheric concentrations with future temperatures because the IPCC Report describes a clear lag in the climate system between any given conce ntration of CO 2 (even if maintained for long periods) and the subsequent average worldwide and regional temperature, precipitation, and extreme9

- 8 weather regimes. For example, a major determinant of climate response is “equilibrium climate sensitivity”, a me asure of the climate system response to sustained radi ative 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 li kely 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 CO 2 mitigation scenarios that aim to meet specific temperature

levels.

Because of how complex global climate systems are, it is difficult to know to what extent

and w hen particular CO 2 emissions reductions will impact global warming. However, as Table

16.3 .1 indicates, the rule is expected to reduce CO 2 emissions associated with energy consumption in buildings.

9.4 ANALYTICAL METHODS F OR AIR EMISSIONS

For each of the c onsidered Efficiency Level s, DOE calculated total power

- sector emissions based on output from the NEMS

- BT model.

NEMS provides reference case load shapes for several end uses. The model uses predicted growth in demand for each end use to build up a project ion of the total electric system load growth for each region, which it uses in turn to predict the necessary additions to capacity. DOE uses

NEMS

- BT to account for the implementation of energy conservation standards by decrementing the appropriate referenc e case load shape. For ASHRAE products the cooling end use load shape was

selected , and t he NEMS was decremented with commercial sector energy savings. T he energy decrements are also divided amongst the nine U.S. Census divisions based upon the share of energy end use consumption in each division, as given in NEMS.

DOE used the site energy savings developed in the national impact analysis (chapter 8 ) for

each Efficiency Level as input to NEMS

- BT. The magnitude of the energy decrement that would be require d for NEMS

- BT to produce stable results out of the range of numerical noise is larger than the highest efficiency standard under consideration. Therefore, DOE estimated results corresponding to

each Efficiency Level using interpolation. DOE ran higher ener gy use reduction levels in NEMS

- BT, representing multipliers of each Efficiency Level , and used these outputs to linearly interpolate the results to estimate actual changes in generation and capacity due to the standard.

Although the current time horizon of NEMS

- BT is 2035, other parts of the energy conservation standards analysis extend through the year 204 3 . It is not feasible to extend the forecast period of NEMS

- BT for the purposes of this analysis, nor does DOE/EIA have an approved method for extrapo lation of many outputs beyond 2035. While it might seem reasonable to make simple linear extrapolations of results, in practice this is not advisable because outputs could be contradictory. An analysis of various trends sufficiently detailed to guarantee c onsistency is beyond the scope of this work, and, in any case, would involve a great deal of uncertainty. Therefore, all extrapolations beyond 2035 are simple replications of year 2035 results. To emphasize the9

- 9 extrapolated results wherever they appear, th ey are shaded in gray to distinguish them from actual

NEMS

- BT results.

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 restriction s 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 SO 2 emissions allowances according to the Clean Air Act Amendments. Consequently, the decision to build a particular capac ity type must consider the cost (if any) of obtaining sufficient allowances. This could involv e purchasing allowances or over

- complying at an existing unit.

For th is analysis , DOE used the version of NEMS

- BT based on AEO 2011 , which assumes the implementa tion of CAIR. Thus, DOE’s analysis assume s the presence of nationwide emission caps on SO 2 and caps on NO X emissions in the 28 States covered by CAIR. DOE expects that the NEMS

- BT based on AEO 2012 will incorporate implementation of the Transport

Rule.

SO 2 emissions from affected Electric Generating Units (EGUs) are subject to nationwide and regional emissions cap and trading programs, and DOE has determined that these programs create uncertainty about the standards’ impact on SO 2 emissions. The attainment of emissions caps is typically flexible among EGUs and is enforced through the use of emissions allowances and tradable permits. Under existing EPA regulations, any excess SO 2 emissions allowances resulting from the lower electricity demand caused by the imposition of an efficiency standard could be used to permit offsetting increases in SO 2 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 red uction in SO 2 emissions from the standards. While there remains some uncertainty about the ultimate effects of efficiency standards on SO 2 emissions covered by the existing cap and trade system, the NEMS

- BT modeling system that DOE uses to forecast

emissio ns reductions currently indicates that no physical reductions in power sector emissions

would occur for SO 2

. i

i In contrast to the modeling forecasts of NEMS

- B T that SO 2 emissions will remain at the cap, during the years 2007 and 2008, SO 2 emissions were below the trading cap. This raises the possibility that standards could cause some

reduction in SO 2 emissions. However, because DOE does not have a method to pr edict when emissions will be below the trading cap, it continues to reply on NEMS

- BT and thus does not estimate SO 2 emissions reductions at

this time.9

- 10 The CAIR established a cap on NO

x 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 for water and evaporatively cooled products, VRF water source heat pumps, and computer room air

conditioners may have little or no physical e ffect 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 SO 2 emissions.

With respect to Hg, in the absence of CAMR or an other trading program, a DOE standard would likely reduc e Hg emissions and DOE uses NEMS

- BT to estimate these emission

reductions. However, DOE continues to review the impact of rules that reduce energy consumption on Hg emissions, and may revise its assessment of Hg emission reductions in future rulemakings.

9.5 EFFECTS ON POWER PLA NT EMISSIONS

Table 9 .5.1 shows AEO201 1 R eference C ase 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 Efficiency Level s are promulgated (the base case).

Table 9.5.1 Power Sector Emissions Forecast from AEO201 1 Reference Case

NEMS

- BT Results 2010 2015 2020 2025 2030 2035

CO 2 (million metric tons) 2,303 2,138 2,225 2,360 2,444 2,526

NO X (million tons) 2.57 1.98 1.98 2.00 2.01 2.03

Hg (tons) 40.5 26.8 26.8 28.0 28.7 29.3

Table 9 .5

. 2 through Table 9 .5

. 4 show the estimated changes in power plant emissions of

CO 2 , NO X, and Hg in selected years for each of the Efficiency Level s considered in this rulemaking

. As in Table 9 .5.1 , values for CO 2 are given in metric tons , while values for NO X and Hg are given in short tons.9

- 11 Table 9.5.2 Power Sector Emissions Impact s Forecasts for Water and Evaporative

Cooled Product Efficiency Level s

NEMS-BT Results* Difference from AEO2011 Reference Case

Total

2010 2015 2020 2025 2030 2035 2040 2042 2043 2013-2043

ASHRAE

CO 2 (Mt/yr) 0.00 0.00 0.00 -0.01 0.00 0.00 0.00 0.00 0.00 -0.099

NOx (1,000 tons/yr) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 -0.081
Hg (ton/yr) 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 -0.001

13 EER (Water)/12.5 EER (Evap)

CO 2 (Mt/yr) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 -0.096

NOx (kt/yr) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 -0.079

Hg (ton/yr) 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 -0.001

14 EER (13.1 Evap)

CO 2 (Mt/yr) 0.00 0.00 0.00 -0.01 -0.01 -0.01 -0.01 -0.01 -0.01 -0.253

NOx (1,000 tons/yr) 0.00 0.00 0.00 -0.01 -0.01 -0.01 -0.01 -0.01 -0.01 -0.208

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

15 EER (13.1 Evap, 14.8 VL Water)

CO 2 (Mt/yr) 0.00 0.00 -0.01 -0.02 -0.02 -0.02 -0.02 -0.02 -0.02 -0.363

NOx (1,000 tons/yr) 0.00 0.00 -0.01 -0.01 -0.01 -0.01 -0.01 -0.01 -0.01 -0.298

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

Max Tech

CO 2 (Mt/yr) 0.00 0.00 -0.01 -0.02 -0.02 -0.02 -0.02 -0.02 -0.02 -0.371

NOx (1,000 tons/yr) 0.00 0.00 -0.01 -0.01 -0.01 -0.01 -0.01 -0.01 -0.01 -0.305

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

*CO 2 results are in metric tons, NO X and Hg results are in short tons. Extrapolation9

- 12 Table 9.5.3 Power Sector Emissions Impact Forecasts for VRF Wate r Source Heat Pump Efficiency Level s

NEMS-BT Results* Difference from AEO2011 Reference Case

Total

2010 2015 2020 2025 2030 2035 2040 2041 2042 2013-2042

ASHRAE

CO 2 (Mt/yr) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.000

NOx (1,000 tons/yr) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.000
Hg (ton/yr) 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Level 1

CO 2 (Mt/yr) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 -0.054

NOx (kt/yr) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 -0.044

Hg (ton/yr) 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 -0.001

Level 2

CO 2 (Mt/yr) 0.00 0.01 -0.02 -0.03 -0.04 -0.04 -0.04 -0.04 -0.04 -0.823

NOx (1,000 tons/yr) 0.00 0.00 -0.01 -0.03 -0.03 -0.04 -0.04 -0.04 -0.04 -0.675

Hg (ton/yr) 0.000 0.000 0.000 0.000 0.000 -0.001 -0.001 -0.001 -0.001 -0.009

Level 3

CO 2 (Mt/yr) 0.00 0.01 -0.04 -0.08 -0.08 -0.10 -0.10 -0.10 -0.10 -1.96

NOx (1,000 tons/yr) 0.00 0.01 -0.03 -0.07 -0.07 -0.08 -0.08 -0.08 -0.08 -1.60

Hg (ton/yr) 0.000 0.000 0.000 -0.001 -0.001 -0.001 -0.001 -0.001 -0.001 -0.022

Max Tech

CO 2 (Mt/yr) 0.00 0.02 -0.07 -0.14 -0.15 -0.19 -0.19 -0.19 -0.19 -3.58

NOx (1,000 tons/yr) 0.00 0.02 -0.06 -0.12 -0.13 -0.15 -0.15 -0.15 -0.15 -2.93

Hg (ton/yr) 0.000 0.000 0.000 -0.001 -0.002 -0.002 -0.002 -0.002 -0.002 -0.040

*CO 2 results are in metric tons, NO X and Hg results are in short tons. Extrapolation9

- 13 Table 9.5.4 Power Sector Emissions Impact Forecasts for Computer Room Air

Conditioner Efficiency Level s

NEMS-BT Results* Difference from AEO2011 Reference Case

Total

2010 2015 2020 2025 2030 2035 2040 2041 2042 2012-2042

ASHRAE

CO 2 (Mt/yr) 0.00 0.00 -0.01 -0.01 -0.01 -0.01 -0.01 -0.01 -0.01 -0.177

NOx (kt/yr) 0.00 0.00 -0.01 -0.01 -0.01 -0.01 -0.01 -0.01 -0.01 -0.145

Hg (ton/yr) 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 -0.001

Level 1

CO 2 (Mt/yr) 0.00 0.01 -0.04 -0.09 -0.10 -0.10 -0.10 -0.10 -0.10 -2.14

NOx (1,000 tons/yr) 0.00 0.01 -0.04 -0.08 -0.08 -0.08 -0.08 -0.08 -0.08 -1.76

Hg (ton/yr) 0.000 0.000 0.000 -0.001 -0.001 -0.001 -0.001 -0.001 -0.001 -0.023

Level 2

CO 2 (Mt/yr) 0.00 0.05 -0.16 -0.35 -0.38 -0.40 -0.40 -0.40 -0.40 -8.06

NOx (1,000 tons/yr) 0.00 0.05 -0.14 -0.30 -0.32 -0.32 -0.32 -0.32 -0.32 -6.62

Hg (ton/yr) 0.001 0.000 -0.001 -0.004 -0.005 -0.005 -0.005 -0.005 -0.005 -0.087

Level 3

CO 2 (Mt/yr) 0.00 0.12 -0.38 -0.81 -0.89 -0.92 -0.92 -0.92 -0.92 -18.7

NOx (1,000 tons/yr) 0.00 0.11 -0.34 -0.69 -0.73 -0.74 -0.74 -0.74 -0.74 -15.4

Hg (ton/yr) 0.002 0.001 -0.002 -0.008 -0.011 -0.012 -0.012 -0.012 -0.012 -0.203

Max Tech

CO 2 (Mt/yr) 0.00 0.20 -0.63 -1.35 -1.48 -1.53 -1.53 -1.53 -1.53 -31.1

NOx (1,000 tons/yr) 0.00 0.18 -0.56 -1.14 -1.22 -1.23 -1.23 -1.23 -1.23 -25.6

Hg (ton/yr) 0.003 0.002 -0.003 -0.014 -0.018 -0.020 -0.020 -0.020 -0.020 -0.337

*CO 2 results are in metric tons, NO X and Hg results are in short tons. Extrapolation9

- 14 9.6 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. Upstream processes include the mining of coal or extraction of natural gas, physical preparatory and cleaning processe s, 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 g as 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 DO E environmental assessment documents, find that an amount approximately equal to eight percent, by mass, of emissions (including SO 2 ) from coal production are due to mining, preparation that includes cleaning the coal, and transportation from

the mine to t he power plant. 13 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 9 .6.1 for CO 2 and NO X . 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 9.6.1 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

CO 2 2.7 11.9

NO X 5.8 40

9.7 SUMMARY OF EMISSIONS IMPACTS

Table 9 .7 .1 summarize s the estimated emissions impacts for each of the Efficiency

Level s for water and evaporatively cooled products, VRF water source heat pumps, and computer room air conditioners

. It show s cumulative changes in emissions for CO 2 , NO X , and9

- 15 Hg for 2014 through 2043 for each of the Effi ciency Level s

. C umulative CO 2 , NO X , and Hg

e missions are reduced compared to the R eference case for all Efficiency Level s. For comparison,

t he cumulative power sector emissions in the AEO 201 1 R eference case, over the period 2014 through 2043

, ar e 71,472 Mt for CO 2 , 60,127 kt for NOx, and 855 tons for H g

.

Table 9.7.1 Cumulative Emissions Reductions Under ASHRAE Efficiency Level s *

Level 1 Level 2 Level 3 Level 4 Level 5 Water and Evaporative Cooled Products

CO 2 (Mt)

NO X (kt) Hg (t) 0.099

0.081

0.001 0.096

0.079

0.001 0.253

0.208

0.003 0.363

0.298

0.004 0.371

0.305

0.004 VRF Water Source Heat Pumps

CO 2 (Mt)

NO X (kt) Hg (t) 0.000

0.000

0.000 0.054

0.044

0.001 0.823

0.675

0.009 1.96

1.60

0.022 3.58

2.93

0.040 Computer Room Air Conditioners

CO 2 (Mt)

NO X (kt) Hg (t) 0.177

0.145

0.001 2.14

1.76

0.023 8.06

6.62

0.087 18.7

15.4

0.203 31.1

25.6

0.337

* Values for CO 2 are given in metric tons, while values for NO X and Hg are given in short tons.9

- 16 REFERENCES

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. http://www.epa.gov/air/nitrogenoxides/

3 U.S . Environmental Protection Agency, Mercury, 20 11. http://www.epa.gov/mercury/

4 Trasande, L., C. Schechter, K.A. Haynes, and P.J. Landrigan,, Applying Cost Analyses to Drive Policy That Protects Children : Mercury as a Case Study. Annals of the New York Academy of Sciences, 2006. 1076

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28606.

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– Impacts, Adaptation and Vulnerability. http://www.ipcc

- wg2.gov

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- Use Change And Forestry, 2000. http://www.grida.no/publications/other/ipcc_sr/?src=/Climate/ipcc/land_use/index.htm

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- 17 13 DeLuchi, M. A., Emissions of Greenhouse Gases from the Use of Transp ortation Fuels and Electricity, Volume 2: Appendixes A

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