On June 2, 2014, the U.S. Environmental Protection Agency (EPA) released its proposed Carbon Pollution Standards for Existing Power Plants  (known as the Clean Power Plan), per its authority under Section 111(d)  of the Clean Air Act (CAA). The development of this rule was announced by President Obama during his June 25, 2013, climate policy speech . The Clean Power Plan would establish different target emission rates (lbs of CO2 per megawatt-hour) for each state due to regional variations in generation mix and electricity consumption, but overall is projected to achieve a 30 percent cut from 2005 emissions by 2030, with an interim target of 25 percent on average between 2020 and 2029.
See more resources and maps at the C2ES Carbon Pollution Standards Resource Page .
Why is regulation of greenhouse gas emissions from existing power plants important?
Electric power generation is responsible for nearly 40 percent of U.S. carbon dioxide emissions.
Figure 1: 2012 U.S. CO2 Emissions
Source: Energy Information Administration
Since the federal government adopted new vehicle efficiency standards  last summer to address transportation emissions through 2025, the power sector represents the greatest opportunity for greenhouse gas reductions.
Figure 2: Electric Power Sector Carbon Dioxide Emissions without Proposed Emission Standards
Source: Energy Information Administration
Power sector emissions have declined over the past five years in part due to the economic downturn, increased energy efficiency, greater use of renewable energy and a switch from coal, the most carbon-intensive fossil fuel, to natural gas, the least carbon-intensive (in terms of combustion). In the absence of any policy changes, the U.S. Energy Information Administration projects that as the economy grows and natural gas prices rise slowly over the next five years, emissions will rise. The Clean Power Plan will have to push against these underlying trends.
Figure 3: Distribution of Power Plants across the Contiguous United States
Source: Energy Information Administration 
What is in EPA’s proposal?
Typically, EPA regulations are set at the federal level and then administered by states. For example, EPA sets a limit on the level of smog in the atmosphere, and states then submit plans for how they will meet that standard. Once approved by EPA, states then administer these plans, known as State Implementation Plans.
The proposed Clean Power Plan is similar in that states would be given a target emissions rate, but have broad flexibility to determine how to achieve that target. Each state would be assigned a carbon emissions baseline based on its level of carbon emissions from fossil-fired power plants divided by its total electricity generation. (See our Proposed State Emission Rate Targets Map. ) Electricity generation in this case includes fossil generation, nuclear, renewables, plus generation avoided through the use of energy efficiency programs. A target for 2030 is then established for each state based on its capacity to achieve reductions using the following four “building blocks” identified by EPA:
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.
Each state could then meet its established target however it sees fit. States could join multi-state programs to reduce emissions collectively, for example through a cap-and-trade program.
How much flexibility will states have to minimize costs?
States would have considerable flexibility to adopt a variety of approaches to reduce carbon dioxide emissions from the power sector, if they can demonstrate that they will achieve the emissions target.
Among the possibilities:
How much will this rule cost?
EPA projects that the compliance costs for this rule would be between $7.3 billion and $8.8 billion annually by 2030. EPA projects that this would lead to about a 3 percent increase in electricity rates by 2030. The rule would deliver considerable benefits as well, including a total of $55 billion to $93 billion in public health benefits by 2030, as projected by EPA. The rule could also reduce electricity consumption, meaning a homeowner’s electricity bill could stay the same or even decrease. It is important to weigh any costs of the Clean Power Plan against the costs of allowing carbon dioxide emissions to continue to rise unabated, contributing to climate change. The costs of climate impacts such as more frequent and intense heat waves, higher sea levels, and more severe droughts, wildfires and downpours, are projected to be much higher.
What can power plants do to reduce emissions?
An individual power plant could reduce its greenhouse gas emission rate by using fuel more efficiently or by switching to a lower carbon fuel, such as natural gas or biomass instead of coal. However, states would be complying with this rule on a statewide basis using any number of emission reduction options. As long as states met carbon dioxide targets broadly, action would not necessarily be required at particular power plants. States could meet their emissions targets by increasing their consumption of renewable electricity relative to fossil-generated electricity or improving energy efficiency. Options to reduce carbon dioxide emissions in the power sector are illustrated in Figure 4.
Figure 4: Opportunities to reduce carbon dioxide emissions in the power sector
How will existing state policies, such as the Regional Greenhouse Gas Initiative, be affected?
States would have significant flexibility in setting regulations for existing power plants within their borders, but are required to follow the broad limits in EPA’s proposed rule. Since states have been given the authority to use market-based mechanisms , the nine Northeast states participating in the Regional Greenhouse Gas Initiative (RGGI) would be able to demonstrate that their cap-and-trade  program for power plants satisfies the required emission reductions, and that further regulation is therefore unnecessary. Policy measures that states might employ to achieve their carbon targets are listed in Table 1.
Table 1: Policy options to reduce power sector carbon dioxide emissions
|Power plant performance standard||Each power plant must achieve a set emissions intensity||California, New York, Washington|
|Renewable Portfolio Standard||Utilities must deliver a set percentage of renewable electricity||Colorado, Hawaii, Kansas, Missouri, Nevada, Rhode Island, and others |
|Energy Efficiency Resource Standard||Utilities must cut demand by a set amount by target years||Arizona, Connecticut, Maryland, Minnesota, Texas, and others |
|Decoupling||Reduce utility incentive to deliver more electricity by decoupling revenue and profit||California, Idaho, Massachusetts, Michigan, Oregon, and others |
|Net Metering||Encourage residential solar by paying homeowners to put excess electricity back on grid||Arkansas, Colorado, Georgia, Louisiana, and others |
|Cap & Trade||Issue a declining number of carbon allowances, which must be surrendered in proportion to each plant’s emissions||California, Regional Greenhouse Gas Initiative|
|Carbon Tax||Charge a tax for emitting carbon||British Columbia|
|Grid Operator Carbon Fee||Add a carbon price to grid operator decision over which power plants to run||None currently|
|Appliance Efficiency Standards||Require new appliances sold to meet set electricity consumption standards||California, Florida, New Jersey, and others |
|Commercial & Residential Building Codes||Require new buildings to include electricity saving measures||California, Illinois, Maryland, Mississippi, and others |
What happens now?
EPA has been directed by President Obama  to work closely with states, power plant operators, and other stakeholders as it finalizes its guidelines due to their novelty and far-reaching implications. Administration officials have said they aim to issue a final rule by June 2015. The target date for states to submit their proposed plans to EPA is June 30, 2016, but states can apply for a one-year extension. After a plan is submitted, EPA will have a year to either approve plans or send them back to states for revision. If a state does not submit an adequate plan, EPA is authorized to impose a federal plan to drive the necessary reductions.
It is important to note that this action is not voluntary on the part of EPA. According to the Supreme Court in Massachusetts v. EPA  (a decision that was recently reaffirmed ), EPA is legally required to regulate greenhouse gases  under the Clean Air Act if it finds them to endanger public health and welfare, just as EPA has addressed more traditional pollutants for the past 43 years. In 2010, EPA settled a suit with several states and environmental groups by agreeing  to finalize greenhouse gas standards for existing power plants by May 26, 2012.
Additional resources can be found on the C2ES Carbon Pollution Standards Resource Page .