Air Pollution: Emissions from Older Electricity Generating Units
(12-JUN-02, GAO-02-709).
Although fossil fuels--coal, natural gas, and oil--account for
more than two thirds of the nation's electricity, generating
units that burn these fuels are major sources of airborne
emissions that pose health and environmental risks. To limit
emissions and protect air quality, the Environmental Protection
Agency (EPA) regulates emissions of sulfur dioxide and nitrogen
oxides from a variety of sources including electricity generating
units that burn fossil fuels, other industrial sources, and
automobiles. Older electricity generating units--those that began
operating before 1972--emit 59 percent of the sulfur dioxide, 47
percent of the nitrogen oxides, and 42 percent of all electricity
produced by fossil-fuel units. Units that began operating in or
after 1972 are responsible for the remainder of the emissions and
electricity production. For equal quantities of electricity
generated, older units, in the aggregate, emitted twice as much
sulfur dioxide and 25 percent more nitrogen oxides than newer
units which must meet the new source standards for these
substances. Older and newer units emitted about the same amount
of carbon dioxide for equal quantities of electricity generated.
Of the older units, those in the Mid-Atlantic, Midwest, and
Southeast produced the majority of the emissions, and in
disproportionate quantities for the amount of electricity they
generated compared with units located in other parts of the
country. Older units that burned coal released a disproportionate
share of emissions for the electricity they produced compared
with units burning natural gas and oil. Thirty-six percent of
older units, in 2000, emitted sulfur dioxide at levels above the
new source standards applicable to newer units, and 73 percent
emitted nitrogen oxides at levels above the standards. These
"additional" emissions--those above the standards for newer
units--accounted for 34 percent of the sulfur dioxide and 60
percent of the nitrogen oxides produced by older units.
Coal-burning units emitted 99 percent of the additional sulfur
dioxide and 91 percent of the additional nitrogen oxides, while
other fossil fuel-burning units accounted for the remainder.
-------------------------Indexing Terms-------------------------
REPORTNUM: GAO-02-709
ACCNO: A03430
TITLE: Air Pollution: Emissions from Older Electricity
Generating Units
DATE: 06/12/2002
SUBJECT: Air pollution
Air pollution control
Comparative analysis
Electric power generation
Environmental monitoring
Fossil fuels
Statistical data
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GAO-02-709
Report to Congressional Committees
United States General Accounting Office
GAO
June 2002 AIR POLLUTION Emissions from Older Electricity Generating Units
GAO- 02- 709
Page i GAO- 02- 709 Air Pollution Letter 1
Results in Brief 3 Background 4 Units that Began Operation before 1972
Emitted More Sulfur
Dioxide and Nitrogen Oxides per Unit of Electricity Produced than Newer
Units 7 Emissions from Older Units Were Often Higher than the Emissions
Standards for Newer Units 12 Agency Comments 17 Scope and Methodology 17
Appendix I Electricity Generation and Emissions from Older Units 20
Appendix II GAO Contacts and Staff Acknowledgments 22
Table
Table 1: Electricity Generation and Emissions of Sulfur Dioxide, Nitrogen
Oxides, and Carbon Dioxide from Older Units by State, 2000 20
Figures
Figure 1: Percentage of Total U. S. Emissions Released by FossilFuel
Generating Units, the Transportation Sector, and Other Sources in 1999 5
Figure 2: Emissions per Megawatt- Hour of Electricity Generated,
2000 8 Figure 3: Sulfur Dioxide Emissions from Older Units, 2000 9 Figure 4:
Nitrogen Oxides Emissions from Older Units, 2000 10 Figure 5: Carbon Dioxide
Emissions from Older Units, 2000 11 Figure 6: Proportion of Older Units?
Emissions that Were Higher
than New Source Standards in 2000 13 Figure 7: Additional Sulfur Dioxide
Emissions from Older Units,
2000 14 Figure 8: Additional Nitrogen Oxides Emissions from Older Units,
2000 15 Contents
Page 1 GAO- 02- 709 Air Pollution
June 12, 2002 The Honorable James M. Jeffords Chairman, Committee on
Environment
and Public Works United States Senate
The Honorable Joseph I. Lieberman Chairman, Subcommittee on Clean Air,
Wetlands, and Climate Change Committee on Environment and Public Works
United States Senate
Electricity is critical to the nation?s economy and standard of living. The
nation depends on a variety of fuels to generate this electricity, including
coal, natural gas, nuclear power, oil, and renewable sources. While fossil
fuels- coal, natural gas, and oil- account for more than two thirds of our
electricity, generating units that burn these fuels are major sources of
airborne emissions that pose human health and environmental risks. Two of
the substances emitted, sulfur dioxide and nitrogen oxides, have been linked
to respiratory illness and acid rain. A third, carbon dioxide, has been
linked to global climate change and its potential adverse effects, including
drought and severe weather conditions. Addressing these concerns without
compromising economic and energy goals continues to pose significant
challenges.
To help limit emissions and protect air quality, the Environmental
Protection Agency (EPA), under the Clean Air Act, regulates emissions of
sulfur dioxide and nitrogen oxides from a variety of sources including
electricity generating units that burn fossil fuels, other industrial
sources, and automobiles. EPA does not regulate carbon dioxide. Under the
Clean Air Act, EPA requires certain electricity generating units built or
modified after August 17, 1971, to meet uniform national emissions standards
for the regulated substances. 1 Units built before that date that have not
undergone modifications do not have to meet these standards. In passing the
act, the Congress directed EPA to establish standards for units built or
1 The standards are called New Source Performance Standards and establish
the maximum allowable emissions from new sources and existing sources that
undergo modifications. For simplicity, we refer to them as ?new source
standards.?
United States General Accounting Office Washington, DC 20548
Page 2 GAO- 02- 709 Air Pollution
modified after that date, on the basis of evidence that adding pollution
controls at the time of construction was more efficient than adding them to
all existing units.
Many of the older units still operate- 1,396 (57 percent) of the fossil-
fuel units that generated electricity in 2000 began operating before 1972. 2
(We refer to fossil- fuel generating units that began operation before 1972
as
?older units? and those that began operating in 1972 or later as ?newer
units.?) Provided they otherwise comply with the act, these older units may
legally emit sulfur dioxide and nitrogen oxides at higher rates than newer
units that are subject to new source standards. Thus, one way of describing
the air quality impact of the older units is to estimate their
?additional? emissions- that is, the difference between their actual
emissions during a given period and the maximum emissions allowed under the
new source standards.
In May 2001, the administration issued a National Energy Policy report,
which cited forecast needs by the Energy Information Administration for
additional power plants over the next 20 years. In your September 2001
letter, you asked us to provide information on, among other things, air
emissions from future electricity generation. As part of this work, which we
will present in a subsequent report, we obtained information and briefed
your offices on emissions in 2000 (the most current data available) from
existing units that burned fossil fuel. This report transmits that
information. Specifically, we determined
the proportions of sulfur dioxide, nitrogen oxides, and carbon dioxide
emitted and electricity generated by older fossil- fuel units (as a group)
relative to newer units (as a group) in 2000, as well as the locations and
type of fuel burned by units responsible for the majority of the emissions;
and
the proportions of older fossil- fuel units that, in 2000, emitted sulfur
dioxide and nitrogen oxides at rates above the new source standards
applicable to newer units, the location of these additional emissions, and
the type of fuel burned by these units.
To address these objectives we analyzed data on air emissions and
electricity generation from units with a generating capacity greater than
2 We used 1972 as the cutoff date for our analysis- instead of August 17,
1971- because data on the age of generating units were only available for
full years.
Page 3 GAO- 02- 709 Air Pollution
15 megawatts. 3 We obtained these data from Platts/ RDI, a private vendor
that integrates data on air emissions from EPA with data on electricity
generation and the age of individual units from the Energy Information
Administration. While these data were the most comprehensive available, they
may understate the total emissions from fossil- fuel units because some
units are not required to report their emissions to regulatory agencies. The
units that did not report emissions, however, generated less than 1 percent
of the electricity from older units in 2000. Of the 1,396 operating older
units, 1,157 (83 percent) reported emissions data in 2000.
Older electricity generating units- those that began operating before 1972-
emitted 59 percent of the sulfur dioxide, 47 percent of the nitrogen oxides,
and 42 percent of the carbon dioxide from fossil- fuel units in 2000, while
generating 42 percent of all electricity produced by fossil- fuel units.
Units that began operating in or after 1972 were responsible for the
remainder of the emissions and electricity production. For equal quantities
of electricity generated, older units, in the aggregate, emitted about twice
as much sulfur dioxide and about 25 percent more nitrogen oxides than did
the newer units which must meet the new source standards for these
substances. Older and newer units emitted about the same amount of carbon
dioxide for equal quantities of electricity generated. Of the older units,
those in the Mid- Atlantic, Midwest, and Southeast produced the majority of
the emissions, and in disproportionate quantities for the amount of
electricity they generated compared with units located in other parts of the
country. Older units that burned coal released a disproportionate share of
emissions for the electricity they produced compared with units burning
natural gas and oil.
In 2000, 36 percent of older units emitted sulfur dioxide at levels above
the new source standards applicable to newer units, and 73 percent emitted
nitrogen oxides at levels above the standards. These ?additional?
emissions- those above the standards for newer units- accounted for 34
percent of the sulfur dioxide and 60 percent of the nitrogen oxides produced
by older units. Most of the additional emissions were released from units
located in the Mid- Atlantic, Midwestern, and Southeastern United States.
Coal- burning units emitted 99 percent of the additional sulfur dioxide and
91 percent of the additional nitrogen oxides, while other fossil fuel-
burning units accounted for the remainder.
3 A megawatt is one million watts, or enough electricity to power about 750
homes. Results in Brief
Page 4 GAO- 02- 709 Air Pollution
Sulfur dioxide and nitrogen oxides have been linked to a variety of health
and environmental concerns, and carbon dioxide has been linked to global
warming. For example, sulfur dioxide and nitrogen oxides contribute to the
formation of fine particles, 4 and nitrogen oxides contribute to the
formation of ozone. 5 Both fine particles and ozone have been linked to
respiratory illnesses. For example, fine particles have been linked to
premature death, aggravated asthma, and chronic bronchitis, while ozone can
inflame lung tissue and increase susceptibility to bronchitis and pneumonia.
In addition to affecting health, sulfur dioxide and nitrogen oxides reduce
visibility and contribute to acid rain, which harms aquatic life and
degrades forests. Carbon dioxide has been linked to increases in air and
ocean temperatures. Such climate changes, by the end of the century, could
cause rising sea levels, droughts, and wind and flood damage, according to
the National Academy of Sciences.
Electricity generating units that burn fossil fuels, along with other
stationary sources (such as chemical manufacturers and petroleum
refineries), and transportation sources (such as cars) emit one or all of
these substances. Figure 1 compares emissions of sulfur dioxide, nitrogen
oxides, and carbon dioxide from fossil- fuel units to those from other
sources in 1999, the most recent year for which data for all three
substances were available. While the overall proportion of each substance
emitted by fossil- fuel units varied- from 67 percent of all sulfur dioxide
to 23 percent of all nitrogen oxides- these units emitted more of each
substance than any other industrial source in 1999.
4 Sulfur dioxide and nitrogen oxides can transform into fine particles in
the atmosphere. Fine particles are a subset of particulate matter, a
regulated pollutant. 5 Ozone, a regulated pollutant, forms when nitrogen
oxides react with volatile organic compounds in the presence of heat and
sunlight. Background
Page 5 GAO- 02- 709 Air Pollution
Figure 1: Percentage of Total U. S. Emissions Released by Fossil- Fuel
Generating Units, the Transportation Sector, and Other Sources in 1999
Note: Transportation data for nitrogen oxides and sulfur dioxide include
only highway vehicles. Data for carbon dioxide include other transportation
sources, such as aircraft and boats. Percentages for nitrogen oxides do not
total 100 due to rounding.
Source: EPA.
Under the Clean Air Act, EPA establishes air quality standards and regulates
emissions from a number of sources, including electricity generating units
that burn fossil fuels. The act required EPA to issue regulations
establishing federal performance standards for new sources of air pollution
within certain categories of stationary sources. Accordingly, EPA issued new
source standards for certain generating units with a capacity greater than
73 megawatts that were built or modified after August 17, 1971. Over time,
EPA has made the standards more stringent, subjecting other types of units
and those with a lower generating capacity to the standards. The standards
do not apply to older units built before that date that have not been
modified, although some older units do meet the standards. In addition,
under a program called New Source Review, older units must install modern
pollution controls when they make ?major
modifications? that significantly increase their emissions. The level of
control required depends on the air quality in the area where the unit is
located- a unit in an area that does not meet federal air quality standards
must install more stringent controls. 6
6 In recent years, the Department of Justice and/ or EPA have brought nine
legal actions against the owners of coal- fired power plants, alleging
violations of New Source Review. As of May 2002, all nine cases were in
litigation and/ or settlement negotiations. EPA and the Department of
Justice settled similar actions in 1999 and 2002.
Page 6 GAO- 02- 709 Air Pollution
Although older units are generally excluded from the new source standards,
they are subject to the acid rain provisions of the Clean Air Act Amendments
of 1990. The 1990 amendments directed EPA to reduce emissions of sulfur
dioxide from electricity generating units by setting a limit, known as a
?cap,? on emissions from all units and establishing an emissions trading
program. Under the trading program, each unit received emissions
?allowances? that represent the right to emit one ton of sulfur dioxide. The
allowances may be bought, sold, or banked for use in later years, but
generating unit owners or operators must own enough allowances at the end of
each year to cover their annual emissions. Although the program did not
start until 1995, some units affected by the program complied earlier,
according to EPA, thereby reducing sulfur dioxide emissions by about 2.2
million tons between 1990 and the end of 1994. Between 1995 and the end of
2000, the affected units reduced their sulfur dioxide emissions by 2. 5
million tons (from 13.7 million tons in 1994 to 11.2 million tons in 2000)-
a decline of about 18 percent. EPA expects the program to result in further
reductions in sulfur dioxide emissions between 2000 and 2010.
To reduce emissions of nitrogen oxides, the acid rain provisions of the 1990
amendments limited the annual rate of emissions for individual units, rather
than imposing an annual aggregate tonnage of emissions. 7 To achieve
emissions reductions while minimizing the burden on generators, the
legislation allowed companies with multiple units to comply with the
prescribed rate by averaging their emissions rates across two or more units
and ensuring that the average did not exceed the prescribed rate. Thus,
individual older units may continue to emit at levels above the prescribed
annual emissions rate. Although the program started in 1996, some of the
affected units complied earlier, according to EPA, thereby reducing
emissions of nitrogen oxides by 700,000 tons between 1990 and the end of
1995. Between 1996 and the end of 2000, the affected units reduced their
emissions of nitrogen oxides by 900,000 tons (from 6. 0 million tons in 1995
to 5.1 million tons in 2000)- a decline of 15 percent.
7 The emissions rates are expressed in pounds of emissions per British
thermal unit (Btu) of energy consumed as fuel by the unit.
Page 7 GAO- 02- 709 Air Pollution
In 2000, older units emitted more sulfur dioxide and nitrogen oxides- and
about the same amount of carbon dioxide- per unit of electricity produced
than newer units. For each megawatt- hour of electricity generated, older
units, in the aggregate, emitted about twice as much sulfur dioxide as newer
units- 12.7 pounds at older units, compared with 6.4 pounds at newer units.
Older units also emitted about 25 percent more nitrogen oxides than newer
units- 4.7 pounds versus 3. 8 pounds- for every megawatt- hour of
electricity generated. Older and newer units both emitted about 1 ton of
carbon dioxide for each megawatt- hour of electricity generated. (See fig.
2.) Overall, while generating 42 percent of the electricity, older units
emitted 59 percent of the sulfur dioxide, 47 percent of the nitrogen oxides,
and 42 percent of the carbon dioxide from fossil- fuel units. 8 Units that
began operating in 1972 or after were responsible for the remainder of the
emissions and electricity production.
8 Total electricity generated by older fossil- fuel units was 1.001 billion
megawatt- hours in 2000, compared with 1. 398 billion megawatt hours
generated by newer fossil- fuel units. Electricity generated by older units
totaled about 28. 6 percent of all U. S. electricity production, including
production by nuclear and renewable sources. Units that Began
Operation before 1972 Emitted More Sulfur Dioxide and Nitrogen Oxides per
Unit of Electricity Produced than Newer Units
Page 8 GAO- 02- 709 Air Pollution
Figure 2: Emissions per Megawatt- Hour of Electricity Generated, 2000
Source: GAO analysis of Platts/ RDI data.
Of the older units, those in the Mid- Atlantic, Midwest, and Southeast
released most of the emissions, and in disproportionate quantities for the
amount of electricity they produced. 9 Specifically, older units in these
regions accounted for 87 percent of the sulfur dioxide, 75 percent of the
nitrogen oxides, and 70 percent of the carbon dioxide emitted from older
units nationwide in 2000, while generating 67 percent of the electricity
from all older units. (App. I presents, by state, data on older units?
electricity generation, emissions per megawatt- hour of electricity
generated, and aggregate emissions.)
Figures 3, 4, and 5 show the location of older units and the amount of
sulfur dioxide, nitrogen oxides, and carbon dioxide they emitted in 2000.
9 These regions correspond to EPA Region 3 (Delaware, District of Columbia,
Maryland, Pennsylvania, Virginia, and West Virginia); Region 4 (Alabama,
Florida, Georgia, Kentucky, Mississippi, North Carolina, South Carolina, and
Tennessee); and Region 5 (Illinois, Indiana, Michigan, Minnesota, Ohio, and
Wisconsin).
Page 9 GAO- 02- 709 Air Pollution
Figure 3: Sulfur Dioxide Emissions from Older Units, 2000
Source: GAO analysis of Platts/ RDI data. Note: Emissions data for units at
the same location were aggregated. Emissions categories were determined by
taking the level of emissions at the highest- emitting unit (or co- located
units) and dividing into five equal categories. Because we aggregated
emissions at co- located units, the numbers in parentheses represent the
number of locations, rather than the number of individual generating units,
in each category.
Page 10 GAO- 02- 709 Air Pollution
Figure 4: Nitrogen Oxides Emissions from Older Units, 2000
Source: GAO analysis of Platts/ RDI data. Note: Emissions data for units at
the same location were aggregated. Emissions categories were determined by
taking the level of emissions at the highest- emitting unit (or co- located
units) and dividing into five equal categories. Because we aggregated
emissions at co- located units, the numbers in parentheses represent the
number of locations, rather than the number of individual generating units,
in each category.
Page 11 GAO- 02- 709 Air Pollution
Figure 5: Carbon Dioxide Emissions from Older Units, 2000
Source: GAO analysis of Platts/ RDI data. Note: Emissions data for units at
the same location were aggregated. Emissions categories were determined by
taking the level of emissions at the highest- emitting unit (or co- located
units) and dividing into five equal categories. Because we aggregated
emissions at co- located units, the numbers in parentheses represent the
number of locations, rather than the number of individual generating units,
in each category.
Older units that burned coal released a disproportionate share of emissions
for the electricity they produced, compared with units burning natural gas
and oil. Coal- burning units emitted 99 percent of the sulfur dioxide, 88
percent of the nitrogen oxides, and 85 percent of the carbon dioxide from
older units nationwide, while generating 79 percent of the total electricity
from older units.
Page 12 GAO- 02- 709 Air Pollution
Older units generally do not have to meet the standards applicable to newer
units, and in 2000, many of the older units emitted sulfur dioxide and
nitrogen oxides at levels higher than what is permitted under the standards
applicable to newer units for one or both of the pollutants. In that year,
36 percent of older units emitted sulfur dioxide at levels above the new
source standard for that pollutant, and 73 percent emitted nitrogen oxides
at levels above the new source standard. Approximately 31 percent of all
older units emitted both pollutants at levels above the new source
standards. 10
As shown in figure 6, in 2000, 34 percent of the total sulfur dioxide
emissions (2.13 million of 6. 34 million tons) and 60 percent of the total
nitrogen oxide emissions (1.41 million of 2.35 million tons) from older
units were ?additional? emissions- that is, emissions at levels above the
standards applicable to newer units. The additional sulfur dioxide emissions
represented 20 percent of the sulfur dioxide emissions from fossil- fuel
units (older and newer), and the additional emissions of nitrogen oxides
represented 28 percent of the emissions of nitrogen oxides from fossil- fuel
units.
10 The standards for both pollutants are expressed in pounds of pollutant
per million British thermal units (Btu) of energy in the fuel, and vary
depending on the age, size, and type of generating unit. The standards used
for this analysis ranged from 0. 5 to 1. 2 pounds of sulfur dioxide per
million Btu, and from 0.15 to 0.80 pounds of nitrogen oxides per million
Btu. The 0. 15 standard became effective in 1998. Emissions from Older
Units Were Often Higher than the Emissions Standards for Newer Units
Page 13 GAO- 02- 709 Air Pollution
Figure 6: Proportion of Older Units? Emissions that Were Higher than New
Source Standards in 2000
Source: GAO Analysis of Platts/ RDI data.
Most of the additional emissions- 91 percent of the sulfur dioxide and 78
percent of the nitrogen oxides- came from units located in the Mid-
Atlantic, Midwest, and Southeast. Figures 7 and 8 show the level of
additional emissions at older units in 2000. The majority of these
emissions- 99 percent of the sulfur dioxide and 91 percent of the nitrogen
oxides- were from coal units, while other fossil fuel- burning units
accounted for the remainder.
Page 14 GAO- 02- 709 Air Pollution
Figure 7: Additional Sulfur Dioxide Emissions from Older Units, 2000
Source: GAO analysis of Platts/ RDI data. Note: Emissions data for units at
the same location were aggregated. Emissions categories were determined by
taking the level of emissions at the highest- emitting unit (or co- located
units) and dividing into five equal categories. Because we aggregated
emissions at co- located units, the numbers in parentheses represent the
number of locations, rather than the number of individual generating units,
in each category.
Page 15 GAO- 02- 709 Air Pollution
Figure 8: Additional Nitrogen Oxides Emissions from Older Units, 2000
Source: GAO analysis of Platts/ RDI data. Note: Emissions data for units at
the same location were aggregated. Emissions categories were determined by
taking the level of emissions at the highest- emitting unit (or co- located
units) and dividing into five equal categories. Because we aggregated
emissions at co- located units, the numbers in parentheses represent the
number of locations, rather than the number of individual generating units,
in each category.
As noted, the additional emissions shown in figure 6 represent the emissions
by older units above the limits applicable to new sources. If the same older
units had generated the same quantity of electricity in 2000 but had met the
new source standards, total emissions would have been lowered by an amount
equal to the computed additional emissions. However, a requirement that
older units meet the standards could have reduced the quantity of
electricity generated, raised the price of electricity, and/ or shifted
generation among units. Among other things, owners might
Page 16 GAO- 02- 709 Air Pollution
have chosen to retire some older units rather than incur the costs of
meeting the standards. According to a December 2000 Energy Information
Administration study, requiring older coal units to install pollution
control equipment would, by 2010, result in retirements that would reduce
the nation?s coal- based electricity generating capacity by 7 percent more
than is otherwise projected (and the total U. S. capacity from all fuels by
3 percent), based on 1999 capacity levels. The study projected that such a
requirement would cause operators of coal units to spend $73 billion dollars
to install pollution control equipment by 2020. The study also concluded
that electricity prices in 2010 would be 4 percent higher with a requirement
to install control equipment than they would be without one. 11
If older units had been required to meet new source standards in 2000, to
the extent practicable, other units might have increased their operations-
for example, by running more hours each day- to meet the demand for
electricity that would have otherwise been produced by the units that
retired. Because it is not possible to determine exactly which units would
have been retired or run more to meet the demand, it is not possible to
quantify precisely what the emissions in 2000 would have been if all units
had been required to meet the new source standards. In addition, generating
units that increased production to meet the demand created by retirements
could have purchased sulfur dioxide emissions allowances from the retired
units. Thus, the net decrease in sulfur dioxide emissions would not have
been as great as the level of additional emissions reported above.
Similarly, it is difficult to predict precisely how such requirements would
affect future emissions levels. Any new coal, natural gas, or oil units
built to replace retired units would, at a minimum, have to meet the new
source standards, which would reduce the emissions for each quantity of
electricity generated.
To meet the new source standards, older units would need to switch fuels, or
add or upgrade pollution control equipment. Some older units already use
pollution control equipment or have taken other actions to reduce their
emissions of sulfur dioxide or nitrogen oxides. For example, we found that
681 older units met the sulfur dioxide standard by burning coal with low
sulfur content. We also found that the use of emissions controls did not
necessarily indicate that the units met the new source standards.
11 See Analysis of Strategies for Reducing Multiple Emissions from Power
Plants: Sulfur Dioxide, Nitrogen Oxides, and Carbon Dioxide, Office of
Integrated Analysis and Forecasting, Energy Information Administration (SR/
OIAF/ 2000- 05, December 2000).
Page 17 GAO- 02- 709 Air Pollution
For example, 399 older units with equipment to control their nitrogen oxide
emissions still exceeded the emissions standard applicable to newer units.
We provided EPA with a draft of this report for review and comment. We
subsequently received comments from the Office of Air Quality Planning and
Standards, and the Office of Atmospheric Programs. EPA generally agreed with
the information presented. Both offices suggested technical changes to the
report, which we have incorporated as appropriate.
To respond to the first objective, we reviewed information from the Energy
Information Administration and EPA on air emissions, electricity generation,
and the age of electricity generating units. While both agencies maintain
such information, the data we needed for this analysis were not readily
available in a user- friendly format. For example, EPA has reliable and
timely emissions data, but the 2000 data were not available with information
on electricity generation and the age of each unit.
Because of these limitations, we obtained alternative data from Platts/ RDI,
a private vendor that integrates EPA?s emissions data with the Energy
Information Administration?s data on electricity generation and the age of
generating units. Specifically, we obtained and analyzed air emissions and
electricity generation data for each active fossil- fuel unit above 15
megawatts in generating capacity that started operating before 1972. For
newer units, we obtained data on aggregate national emissions and
electricity generation at units with a capacity above 15 megawatts. We chose
15 megawatts as the threshold capacity because units above that capacity
accounted for almost all (about 99 percent) of the electricity generation
from all fossil- fuel units in 2000. Because data on air emissions and the
use of control equipment were available for only 1,157 of the 1,396 active
units (83 percent), the data may not fully represent the total level of
emissions and the number of units using control equipment. However, the
units that did not report emissions data generated less than 1 percent of
the electricity from older units and therefore are not likely to have
produced large quantities of emissions.
To respond to the second objective, we identified the applicable new source
standard for each type of unit, as listed in the Code of Federal
Regulations, Title 40, part 60. We then determined the difference between
the actual rate of emissions at each unit, in pounds of pollutant per unit
of fuel consumed, and the rate allowed under the standard that applies to
Agency Comments
Scope and Methodology
Page 18 GAO- 02- 709 Air Pollution
newer units with the same capacity that burn the same fuel. We then
multiplied the difference by the amount of fuel burned in 2000 to determine
the annual level of ?additional? emissions. In cases where EPA has not
issued a standard for a particular type of unit, we excluded such units from
our analysis of additional emissions. Regulations for some types of
generating units were promulgated after 1971, but for purposes of this
report we have not distinguished these units and have classified them as
newer or older units based on their age. For example, EPA promulgated a
regulation in 1978 requiring certain electric utility steam- generating
units to meet new source standards. However, if one of these units was
constructed after August 17, 1971, but before September 18, 1978, we
classified it as a newer unit even though it would not have to meet the new
source standard.
We did not attempt to estimate the costs or benefits of requiring older
units to meet the new source standards. Therefore our analysis does not
allow us to comment on the economic or energy security implications of
requiring older units to meet the standards.
We conducted our work between October 2001 and May 2002 in accordance with
generally accepted government auditing standards.
As agreed with your offices, unless you publicly announce the contents of
this report earlier, we plan no further distribution until 30 days from the
report date. At that time, we will send copies to the Chairman and Ranking
Minority Member of the House Committee on Energy and Commerce and its
Subcommittee on Energy and Air Quality; the House Committee on Government
Reform and its Subcommittee on Energy Policy, Natural Resources, and
Regulatory Affairs; the Ranking Minority Member of the Senate Committee on
Environment and Public Works, and its Subcommittee on Clean Air, Wetlands,
and Climate Change; other interested members of Congress; the Administrator,
EPA; the Secretary of Energy; the Director of the Office of Management and
Budget; and other interested parties. We will also make copies available to
others upon request. In addition, the report will be available at no charge
on GAO?s Web site at http:// www. gao. gov.
Page 19 GAO- 02- 709 Air Pollution
If you have any questions about this report, please contact me at (202) 512-
3841. Key contributors to this report are listed in appendix II.
David G. Wood Director, Natural Resources
and Environment
Appendix I: Electricity Generation and Emissions from Older Units
Page 20 GAO- 02- 709 Air Pollution
Table 1 presents, by state, data on older units? electricity generation;
emissions of sulfur dioxide, nitrogen oxides, and carbon dioxide; and
aggregate emissions of these substances.
Table 1: Electricity Generation and Emissions of Sulfur Dioxide, Nitrogen
Oxides, and Carbon Dioxide from Older Units by State, 2000
State Electricity
Generation (Megawatt
Hours) Sulfur
Dioxide Emissions
Rate (Lbs. per Megawatt
Hour) Sulfur
Dioxide Emissions
(Tons) Nitrogen
Oxides Emissions
Rate (Lbs. per Megawatt
Hour) Nitrogen
Oxides Emissions
(Tons) Carbon
Dioxide Emissions Rate (Tons
per Megawatt
Hour) Carbon
Dioxide Emissions
(Tons)
Alabama 43,841,064 15.9 348,189 5. 4 117,612 1. 1 50,247,087 Arizona 6,
254,947 1.6 4, 965 4.5 14,026 0. 8 5,154,604 Arkansas 4,344,950 1.5 3, 362
2.9 6, 195 0.7 3, 041,883 California 49,643,659 - 0 0. 7 16,196 0. 6
30,594,610 Colorado 9,751,898 6.8 33,234 4. 9 23,764 1. 2 11,486,658
Connecticut 7,569,614 6.3 23,830 2. 6 9,767 0.9 6, 546,837 Delaware
2,915,799 18.9 27,601 4. 0 5,795 1.2 3, 597,684 District of Columbia 62,392
11.7 364 3.3 103 1.2 72,187 Florida 38,894,598 10.1 195,543 5. 7 110,722 1.
0 37,961,898 Georgia 26,114,968 14.4 187,523 6. 2 80,521 1. 0 26,968,799
Idaho 0 - 0 - 0 - 0 Illinois 49,414,341 10.8 267,923 5. 1 125,767 1. 1
56,372,741 Indiana 49,504,150 18.2 449,498 6. 3 156,414 1. 1 54,171,703 Iowa
8,373,882 10.6 44,481 5. 9 24,669 1. 3 10,787,523 Kansas 7,383,865 3.5
13,062 5. 0 18,582 1. 1 8,309,570 Kentucky 43,900,772 17.4 382,785 6. 2
135,662 1. 1 50,019,689 Louisiana 15,061,362 - 0 3. 3 24,915 0. 7 10,361,639
Maine 546,501 17.1 4, 683 3.1 852 0.9 483,827 Maryland 20,043,853 18.9
189,797 5. 8 57,846 1. 0 20,759,129 Massachusetts 16,044,319 8. 2 65,729 3.
1 24,811 1. 0 15,625,832 Michigan 34,882,007 11.7 203,421 3. 9 68,674 1. 1
38,980,846 Minnesota 10,500,702 10.3 53,832 7. 2 37,903 1. 2 12,603,068
Mississippi 7,285,810 4.3 15,745 6. 2 22,470 1. 0 7,347,536 Missouri
27,776,027 8. 8 122,550 6. 5 89,622 1. 1 31,785,320 Montana 1,523,880 5.8 4,
397 3.3 2, 543 1.2 1, 898,300 Nebraska 4,922,776 6.9 16,944 5. 4 13,371 1. 2
5,887,622 New Hampshire 3, 971,049 22.7 45,027 4. 0 7,969 1.2 4, 639,472
Nevada 15,193,917 5. 8 43,920 4. 2 32,155 1. 0 14,629,653 New Jersey
9,146,856 12.6 57,806 6. 3 28,798 1. 1 10,051,576 New Mexico 17,453,290 4. 2
36,895 5. 7 49,592 1. 1 18,612,310 New York 35,195,389 13.0 228,813 3. 3
57,300 1. 0 36,715,581 North Carolina 41,162,804 12.6 258,948 4. 2 87,450 1.
0 41,469,611
Appendix I: Electricity Generation and Emissions from Older Units
Appendix I: Electricity Generation and Emissions from Older Units
Page 21 GAO- 02- 709 Air Pollution
State Electricity
Generation (Megawatt
Hours) Sulfur
Dioxide Emissions
Rate (Lbs. per Megawatt
Hour) Sulfur
Dioxide Emissions
(Tons) Nitrogen
Oxides Emissions
Rate (Lbs. per Megawatt
Hour) Nitrogen
Oxides Emissions
(Tons) Carbon
Dioxide Emissions Rate (Tons
per Megawatt
Hour) Carbon
Dioxide Emissions
(Tons)
North Dakota 4,300,003 20.4 43,911 5. 9 12,657 1. 3 5,605,774 Ohio
69,151,066 22.8 789,672 5. 4 188,078 1. 0 71,298,574 Oklahoma 6, 743,970 - 0
3. 8 12,725 0. 6 4,352,123 Oregon 0 - 0 - 0 - 0 Pennsylvania 80,866,255 20.5
830,616 3. 9 159,062 1. 0 83,278,788 Rhode Island 0 - 0 - 0 - 0 South
Carolina 15,180,903 15.9 121,059 4. 7 35,399 1. 0 15,772,080 South Dakota
393 - 0 - 0 0. 04 Tennessee 41,045,623 19.3 396,165 5. 1 103,751 1. 1
43,178,072 Texas 68,938,998 1. 2 42,411 2. 7 93,228 0. 7 45,508,059 Utah
2,118,089 4.2 4, 462 3.4 3, 555 0.9 1, 978,780 Virginia 27,170,249 14.8
200,460 4. 9 66,277 1. 1 29,493,051 Vermont 0 - 0 - 0 - 0 Washington 0 - 0 -
0 - 0 West Virginia 46,981,339 18.6 436,309 6. 4 150,433 1. 0 47,548,879
Wisconsin 21,430,208 10.0 107,205 5. 5 58,913 1. 1 23,606,146 Wyoming 8,
734,567 7.8 34,068 5. 2 22,853 1. 2 10,098,931
Total 1,001,343, 104 - 6,337,203 - 2,358,996 - 1,008,904, 054
Note: There was no reported electricity production or emissions from older
units in Idaho, Oregon, Rhode Island, Vermont, or Washington.
Source: GAO?s analysis of Platts/ RDI data.
Appendix II: GAO Contacts and Staff Acknowledgments
Page 22 GAO- 02- 709 Air Pollution
David G. Wood (202) 512- 3841 Eileen R. Larence (202) 512- 6510
In addition to the individuals named above, Michael Hix, Chase Huntley,
Vincent Price, and Laura Yannayon made key contributions to this report.
Important contributions were also made by Cynthia Norris, Frank Rusco, and
Amy Webbink. Appendix II: GAO Contacts and Staff
Acknowledgments GAO Contacts Acknowledgments
(360147)
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