carbon pollution standards

Carbon Pollution Standards

Carbon Pollution Standards

The U.S. Environmental Protection Agency's (EPA) Clean Power Plan, proposed in June 2014, would limit carbon pollution from existing power plants.

Electric power generation is responsible for nearly 40 percent of U.S. carbon dioxide emissions – making it the largest single source. Reducing power sector emissions is a key part of President Obama’s Climate Action Plan, which aims to reduce overall U.S. greenhouse gas emissions 17 percent below 2005 levels by 2020. His June 2013 presidential memorandum directed EPA to set standards for both new and existing plants.

Under the Clean Power Plan for existing power plants, each state has its own target (due to regional variation in generation mix and electricity consumption). Overall, the rule is designed to cut emissions 30 percent from 2005 emissions by 2030, with an interim target of 25 percent on average between 2020 and 2029.

In September 2013, EPA released a “Carbon Pollution Standard for New Power Plants,” replacing a March 2012 proposal. EPA proposed standards for coal- and natural gas-fired plants (measured as tons of greenhouse gas emissions per megawatt-hour of elec­tricity produced) that states would apply at each regulated plant.

EPA will issue the finalize rules for the Clean Power Plan for existing power plants and the Carbon Pollution Standard for New Power Plants in the summer of 2015.

Explore the issues and options involved in EPA regulation of carbon pollution from power plants through the following resources.

C2ES Resources

External Resources

Carbon Pollution Standards Map


In its proposed Clean Power Plan to reduce carbon dioxide emissions in the power sector, EPA has set a unique target emissions rate for each state to hit by 2030. To develop this target, EPA first determined a carbon emissions baseline (using 2012 data) based on each state’s level of CO2 emissions from fossil-fired power plants divided by its total electricity generation (including fossil-fired generation, renewable generation, and nuclear generation). Targets for 2030 were then established based on the capacity of each state to achieve reductions using the following four “building blocks” identified by EPA:

  1. Make coal-fired power plants more efficient;
  2. Use low-emitting natural gas combined cycle plants more where excess capacity is available;
  3. Use more zero- and low-emitting power sources such as renewables and nuclear; and
  4. Reduce electricity demand by using electricity more efficiently.

Since there is a wide variation among states in both emissions baseline and capacity to leverage each of the four building blocks, there is a wide variation in how much each state must cut from current emissions to hit its 2030 target emissions rate. (See Table 1.)

Each state can meet its established target however it sees fit, and does not need to leverage each building block to the extent that EPA projects. States will be able to convert their target emissions rate (pounds CO2 per megawatt-hour of electricity generated) to a mass-based standard (tons of CO2 emitted per year) to enable a cap-and-trade program. States are also free to join together and work toward an aggregated regional target.

Table 1: Building Block Reduction by State

StateEmissions Rate of Power System, including zero-carbon generation (lbs CO2 / MWh) (2012 Block 1 (Coal-plant Efficiency) Adding Block 2 (Natural Gas Fuel Switching) Adding Block 3 (Renewable and Nuclear Generation) Final Target by Adding Block 4 (Demand-side Energy Efficiency) Total Emissions Reduction Target by 2030
Washington75672844429821571.6%
Arizona1453139484381470251.7%
South Carolina15871506134286677251.4%
Oregon71770156545237248.1%
New Hampshire90588771053248646.3%
Georgia15001433121692683444.4%
Arkansas16341554105899691044.3%
New York97897082865254943.9%
New Jersey92891681161653142.8%
Minnesota*14701389999104287340.6%
North Carolina164715601248112599239.8%
Louisiana14551404104397888339.3%
Tennessee1903179716981322116338.9%
Texas1284123597986179138.4%
Florida1199116988281274038.3%
Virginia13021258104789481037.8%
Massachusetts92591581966157637.7%
Mississippi1093107180975269236.7%
Maryland1870177217221394118736.5%
Oklahoma13871334105396489535.5%
Colorado1714162113341222110835.4%
South Dakota*1135106773290074134.7%
Nevada98897079972064734.5%
Wisconsin1827172814871379120334.2%
New Mexico1586151312771163104833.9%
Illinois1894178416141476127132.9%
Idaho33933933929122832.7%
Delaware1234121199689284131.8%
Michigan1690160314081339116131.3%
Pennsylvania1531145813931157105231.3%
Connecticut76576473364354029.4%
Ohio1850175116731512133827.7%
Utah1813171315081454132227.1%
Alabama1444138512641139105926.7%
Nebraska2009188918031652147926.4%
Alaska1351134012371191100325.8%
California69869766261553723.1%
Kansas1940182818281658149922.7%
Missouri1963184917421711154421.3%
Montana2246211421141936177121.1%
Indiana1924181717721707153120.4%
West Virginia2019189818981687162019.8%
Wyoming2115198819571771171419.0%
Kentucky2158202819781947176318.3%
Iowa*1552146113041472130116.2%
Hawaii1540151215121485130615.2%
Rhode Island90790790786778213.8%
Maine*43743742545137813.5%
North Dakota1994187518751865178310.6%
VermontNo affected sources
D.C.

*In the cases of Iowa, Maine, Minnesota, and South Dakota, the emission rate rises when building block three is added. The 2012 renewable generation levels in these states were higher than what EPA's methodology projects for 2030, meaning EPA assumes lower renewable generation, and therefore higher emission rates, for these states in 2030. These increases in emission rates are reflected by negative percentage changes for the effect of building block three when you click on these states in the map above.

Source: U.S. Environmental Protection Agency, Technical Support Document (TSD) for the CAA Section 111(d) Emission Guidelines for Existing Power Plants: Goal Computation, Appendix 5.

C2ES Carbon Pollution Standards Resource Page

EPA’s proposed carbon standard for power plants is stringent and flexible

The Obama Administration today took a major step toward reducing the carbon dioxide emissions that are impacting our climate. The Environmental Protection Agency (EPA) released its “Clean Power Plan,” which leverages existing authority in the Clean Air Act to propose carbon pollution standards for existing power plants, the largest single source of U.S. carbon emissions. The proposal would cut emissions in the power sector by 30 percent by 2030, based on 2005 levels. We reviewed the basics of the Clean Power Plan with four critical questions in mind:

1. Is the standard based on emission reductions outside the power plant fence line?

The short answer is “yes.” EPA cannot require states or power plant operators to take any specific measures, but it can set the emissions target stringent enough so that it would be challenging to achieve unless certain measures are taken. EPA is proposing state-specific targets based on the capacity of each state to leverage four “building blocks.” They are:

  1. Make fossil fuel power plants more efficient.
  2. Use low-emitting natural gas combined cycle plants more where excess capacity is available.
  3. Use more zero- and low-emitting power sources such as renewables and nuclear.
  4. Reduce electricity demand by using electricity more efficiently.

Although “outside-the-fence-line” measures are not specifically required under the proposal, states would be hard-pressed to meet their targets without using programs to reduce the demand for fossil electricity, by, for example, increasing energy efficiency and encouraging renewable energy.

Looking to Figure 1, EPA has chosen the System-level Option.

Figure 1: Scope of reduction requirements

What to watch in EPA’s power plant carbon emissions proposal

On June 2, the Environmental Protection Agency (EPA) is expected to release its proposal to cut carbon dioxide (CO2) emissions from existing power plants. This proposal is a key element of President Obama’s Climate Action Plan, and will be critical to reducing U.S emissions of CO2, the most common greenhouse gas contributing to climate change.

The proposed rule, being developed under EPA’s authority under Section 111(d) of the Clean Air Act, could be groundbreaking for at least two reasons. First, it has the potential to drive major reductions in the highest emitting sector in the United States – the power sector – which is responsible for nearly 40 percent of U.S. carbon emissions.  Second, EPA has indicated that the proposal will include a number of novel policy provisions to advance low-emitting generation and energy efficiency.

At C2ES, we’ll be looking for answers to four key questions as we read through EPA’s proposal. These questions are expanded upon in our new brief, Carbon Pollution Standards for Existing Power Plants: Key Challenges.

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