FACT SHEET
Proposed ACE Rule - CO2 Emissions Trends
•	On August 21, 2018, the U.S. Environmental Protection Agency (EPA) proposed the
Affordable Clean Energy (ACE) rule which would establish emission guidelines for states to
develop plans to address greenhouse gas (GHG) emissions from existing coal-fired power
plants.
•	The ACE rule would replace the 2015 Clean Power Plan (CPP), which EPA has proposed to
repeal because it exceeded EPA's authority. The CPP was stayed by the U.S. Supreme Court
and has never gone into effect.
•	The proposed ACE rule is informed by the more than 270,000 public comments that EPA
received on its December 2017 Advance Notice of Proposed Rulemaking.
•	The ACE rule has several components: a determination of the best system of emission
reduction (BSER) for GHG emissions from coal-fired power plants, a list of "candidate
technologies" states can use when developing their plans, a new preliminary applicability
test for determining whether a physical or operational change made to a power plant may
be a "major modification" triggering New Source Review, and new implementation
regulations for emission guidelines under Clean Air Act section 111(d).
CO2 EMISSIONS STEADILY DECLINING
•	EPA projects that, compared to a no CPP scenario, the ACE rule will reduce carbon dioxide
(CO2) emissions in 2025 by between 13 and 30 million short tons, resulting in $1.6 billion in
monetized domestic climate benefits.
•	EPA evaluated three illustrative implementation scenarios. EPA estimates that the ACE rule
could reduce 2030 CO2 emissions by an amount equivalent to the annual emissions of up to
5 million cars. The rule could also reduce co-pollutant emissions by up to 2%.
•	These illustrative scenarios suggest that when states have fully implemented the ACE rule,
U.S. power sector CO2 emissions could be around 34% below 2005 levels.
•	CO2 emissions in the power sector have steadily declined in recent years due to a range of
factors including: market forces, technology improvements, regulatory and policy changes.
As a result, the industry has increased the use of natural gas and renewable energy sources.
These trends have resulted in CO2 emission reductions even as the U.S. has sustained
economic growth and job gains across the economy—and this has all happened without the
CPP ever going into effect. The ACE rule will continue this trend.
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40%
GDP
Population
Electricity Generation
Electricity C02 Emissions
Electricity S02 + NOx
	 -100%
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•	The power sector emitted roughly 1.9 billion tons of CO2 in 2017, compared to 2.7 billion
tons in 2005—a 28% decrease.1
o Table 1 in the appendix to this fact sheet provides state-level CO2 emissions data for
2005 and 2016 as well as the state-level percentage of generation by fuel-type for
2016.2
•	Approximately 600 coal-fired electric generating units at 300 facilities could be covered by
this rule.
•	The U.S. leads the world in reducing CO2 emissions. The Energy Information Administration
(EIA) found that U.S. energy-related CO2 emissions fell by 14 percent between 2005 to 2017,
with coal-related CO2 emissions down 39 percent over that period. During that time, global
energy-related CO2 emissions rose by 21 percent.
FOR MORE INFORMATION
•	Additional fact sheets along with copies of the proposed rule and accompanying Regulatory
Impact Analysis are available on EPA's website at https://www.epa.gov/stationarv-sources-air-
pollution/proposal-affordable-clean-energy-ace-rule
1	ElATable 12.6, available at
https://www.eia. gov/totalenergv/data/browser/index.php?tbl=T12.06#/?f=A&start=2005&end=2017&charted=0-
1-6-9.
2	2017 state-level data is not yet available from the Energy Information Administration (EIA).
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APPENDIX
Table 1: CO2 Emissions and Generation Mix by State3

CO2 Emissions
(million short
tons)
2006 2016
2016 Generation Mix
(percent of total generation by fuel-type)4
Coal Natural Nuclear Renewable5 Other6
Gas
Alaska
3.9
3.4
8%
50%
0%
28%
13%
Alabama
92.1
61.2
25%
41%
29%
5%
0%
Arkansas
31.0
34.1
40%
30%
23%
6%
0%
Arizona
58.6
49.0
28%
31%
30%
11%
0%
California
52.0
41.0
0%
47%
10%
43%
0%
Colorado
46.4
39.6
55%
23%
0%
22%
0%
Connecticut
11.9
8.7
0%
48%
47%
3%
2%
District of
0.1
0.0
0%
0%
0%
100%
0%
Columbia







Delaware
6.2
4.0
6%
91%
0%
1%
1%
Florida
138.0
119.0
17%
67%
13%
1%
2%
Georgia
94.5
63.6
29%
41%
27%
3%
0%
Hawaii
9.6
7.4
16%
0%
0%
12%
71%
Iowa
40.7
27.4
45%
5%
9%
40%
0%
Idaho
0.6
1.4
0%
21%
0%
79%
0%
Illinois
103.7
73.3
31%
9%
54%
6%
0%
Indiana
134.5
91.9
74%
20%
0%
6%
1%
Kansas
39.8
28.1
49%
4%
17%
30%
0%
Kentucky
103.7
79.5
84%
10%
0%
5%
2%
Louisiana
42.5
40.2
16%
53%
23%
2%
6%
Massachusetts
25.1
13.2
6%
66%
17%
7%
4%
Maryland
32.6
19.3
38%
13%
40%
7%
1%
Maine
3.4
2.1
1%
33%
0%
63%
3%
Michigan
80.5
60.8
37%
26%
29%
6%
2%
Minnesota
39.5
30.4
39%
15%
24%
21%
1%
Missouri
87.6
68.8
77%
8%
12%
3%
0%
Mississippi
28.2
28.5
9%
82%
10%
0%
0%
Montana
21.3
18.1
51%
2%
0%
44%
3%
North Carolina
78.4
56.1
29%
30%
33%
7%
0%
North Dakota
34.2
32.5
70%
3%
0%
27%
0%
3	ElA's Detailed State Data, available at https://www.eia.gov/electricitv/data/state/.
4	These data exclude industrial and commercial sources.
5	Includes geothermal, hydroelectric (conventional and pumped storage), biomass (including wood and wood
derived fuels), solar (thermal and photovoltaic), and wind.
6	Includes petroleum and other gases.
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Nebraska
24.0
23.9
60%
1%
26%
13%
0%
New Hampshire
7.6
2.7
2%
24%
56%
17%
0%
New Jersey
20.9
22.5
2%
57%
39%
2%
1%
New Mexico
37.0
25.5
56%
30%
0%
14%
0%
Nevada
18.3
15.4
6%
73%
0%
22%
0%
New York
53.6
32.1
1%
42%
31%
24%
1%
Ohio
141.0
87.9
58%
24%
14%
2%
1%
Oklahoma
56.3
39.4
24%
47%
0%
29%
0%
Oregon
7.2
8.7
3%
26%
0%
71%
0%
Pennsylvania
136.0
91.1
26%
31%
39%
3%
0%
Rhode Island
2.6
2.8
0%
96%
0%
4%
0%
South Carolina
43.6
30.1
22%
17%
59%
2%
0%
South Dakota
4.0
2.9
18%
8%
0%
74%
0%
Tennessee
62.5
39.7
39%
14%
38%
8%
0%
Texas
255.0
233.1
30%
45%
10%
15%
0%
Utah
39.6
30.1
69%
22%
0%
9%
0%
Virginia
41.1
37.3
18%
45%
33%
3%
1%
Vermont
0.0
0.0
0%
0%
0%
100%
0%
Washington
10.9
10.6
4%
10%
9%
77%
0%
Wisconsin
48.6
42.7
52%
24%
16%
8%
0%
West Virginia
93.2
74.9
95%
1%
0%
3%
0%
Wyoming
48.8
45.7
88%
0%
0%
12%
0%

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