Regulation Database

President Obama and EPA announced the final Clean Power Plan rule on August 3, 2015. The rule aims to reduce CO2 emissions from existing power plants by 30% below 2005 levels by 2030. To accomplish this, the rule establishes CO2 emission performance rates representing the best system of emission reduction (BSER) for fossil fuel-fired electric utility steam generating units and stationary combustion turbines within each state. States have the flexibility to reach these targets individually or at the regional scale, and to translate the rate-based targets into mass-based targets for compliance purposes. The rule also establishes guidelines for the development, submittal and implementation of state plans to achieve the CO2 emission performance rates.

Rule Documents:

Associated Rule Proposals:


Industry groups and states immediately challenged the final rule in West Virginia v. EPA, No.15-1363 (D.C. Cir. 2015) In February 2016, the U.S. Supreme Court stayed the Clean Power Plan pending review in the D.C. Circuit Court of Appeals. In January 2017, State opponents of the EPA’s Clean Power Plan filed a petition for a new lawsuit, asking the D.C. Circuit Court of Appeals to review EPA’s denial of requests for reconsideration of the rule (which were filed after the rule was finalized but before the Supreme Court stayed its implementation).

On April 4, 2017, EPA  submitted a motion to hold the case in abeyance  pending it’s reconsideration of the rule. On April 28, the court granted EPA’s request and ordered a 60-day stay of the litigation as well as supplemental briefings on whether the case should be remanded to the agency rather than held in abeyance.  The court subsequently prolonged the stay. On September 17, 2019 the court dismissed the case as moot in light of the Affordable Clean Energy (ACE) Rule, discussed below, which formally rescinds the Clean Power Plan.

Deregulatory Actions: 

On March 28, 2017, President Trump issued an executive order directing EPA to review the Clean Power Plan and to rescind or rewrite the rule as needed to promote the President’s goals of energy independence and economic growth. EPA immediately submitted a request to the D.C. Circuit Court of Appeals to hold the West Virginia case in abeyance pending EPA’s reconsideration of the rule. On April 4, 2017, EPA published a notice in the Federal Register announcing that it is reviewing and, if appropriate will initiate proceedings to suspend, revise or rescind the rule.

The March 2017 executive order also directed EPA to review and rescind or re-write the proposed rule establishing federal implementation plans and model trading rules. On April 3, 2017, EPA officially withdrew that rule proposal as well as the rule proposal establishing details for the Clean Energy Incentive Program (CEIP).

On October 16, 2017, EPA published a proposal to repeal the Clean Power Plan. EPA did not specify whether it would promulgate a new rule, under section 111(d) of the CAA, to regulate carbon dioxide emissions from existing power plants.

On November 8, 2017, EPA announced that it was extending the comment deadline for the proposed repeal by 32 days to January 16, 2018.

On December 28, 2017, EPA issued an advanced notice of proposed rulemaking to replace the Clean Power Plan in which it solicited comment on what the EPA should include in a potential new rule to regulate GHG emissions from existing power plants under CAA section 111(d).

On June 19, 2019, EPA published a final rule to repeal and replace the Clean Power Plan, called the Affordable Clean Energy (ACE) Rule.  The ACE Rule gives states wide latitude in deciding how to regulate emissions from power plants. It defines BSER for greenhouse gas emissions from power plants as on-site, heat-rate efficiency improvements. This definition excludes fuel switching and improvements to demand-side energy efficiency.  In addition, the ACE rule does not establish any numeric emission guidelines or reduction targets for states (as the Clean Power Plan did). 

Effects of Staying and Rescinding the Plan: If implemented, the Clean Power Plan would have reduced carbon pollution from the power sector by 32% in 2030, amounting to 870 million tons less carbon pollution, the equivalent of taking 166 million cars off the road for a year. Climate and public health benefits would have reached between $34 and $54 billion annually by 2030 and reduced emissions of toxic air pollutants such as sulfur dioxide would have resulted in the prevention of over 1,500 premature deaths annually. 


On July 8, 2019, a coalition public health and environmental group challenged the ACE Rule in the D.C. Circuit. A coalition of states and cities followed suit on August 13, 2019.

On January 19, 2021, the D.C. Circuit vacated the ACE Rule and directed EPA to go back to the drawing board to issue a new rule. On February 22, the court took final action to vacate the ACE Rule, but agreed to stay a mandate that would vacate the EPA's repeal of the CPP so that it is clear that the CPP will not come into effect. On April 29, a coalition of states asked the Supreme Court to review the D.C. Circuit's ruling. The North American Coal Corporation also filed a petition with the Supreme Court, and coal industry trade groups followed suit as well.

On June 30, 2022, the Supreme Court held that the Clean Air Act did not provide EPA with authority to promulgate the Clean Power Plan, resting its decision on the "major questions doctrine."

Additional Resources