Regulatory Tracker

Regulating Greenhouse Gases for Existing and New Fossil Fuel-Fired Power Plants

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Current Status

On May 9, 2024, EPA published standards for new gas-fired power plants and existing coal-fired power plants. States have two years (until May 2026) to develop state plans for existing coal-fired power plants. Litigation commenced immediately upon EPA’s finalization of the standards with several motions to stay the rule currently before the DC Circuit.

Read our summary of the rules.

Why it Matters

Greenhouse gas (GHG) emissions from the generation of electricity by fossil fuel-fired power plants, or electric generating units (EGUs), makes up roughly 25% of US total GHG emissions. Reducing GHG emissions from power plants is an important step in achieving US GHG emissions reductions, especially as other sectors look to reduce emissions through electrification.

Greenhouse Gas Standards for New Sources

For new, modified, or reconstructed power plants, EPA promulgates regulations under the Clean Air Act’s (CAA) New Source Performance Standards for Greenhouse Gas Emissions (section 111(b). The CAA defines new sources as those constructed after the proposed regulation’s publication date.

Greenhouse Gas Standards for Existing Sources

Once EPA promulgates new source performance standards (NSPS) under section 111(b) of the Clean Air Act, EPA must also issue emission guidelines under section 111(d) for existing sources’ emissions that are not already addressed under the National Ambient Air Quality Standards (section 108) or Hazardous Air Pollutant standards (section 112). Once EPA issues emission guidelines, states must adopt state plans consistent with those guidelines.

Key Resources

EPA’s Final CO2 Standards for the Power Sector: Robust Regulatory Record Sets the Stage for Legal Challenges

Timelines of EPA’s Final Rules to Reduce Climate Changing Pollution from Power Plants

CleanLaw–EPA’s Proposed Power Sector Rules with Jody Freeman, Jay Duffy, Kevin Poloncarz, and Carrie Jenks

Unplugging Emissions: Exploring New EPA Rules on Climate and Health (VIDEO)

CleanLaw—Jody Freeman, Richard Lazarus, and Carrie Jenks Break Down the West Virginia v. EPA Decision, Part 1

CleanLaw—Jody Freeman, Jay Duffy, and Kevin Poloncarz on West Virginia v. EPA—Implications for Regulating the Power Sector, Part 2

Supreme Court Embraces the Major Questions Doctrine as Limiting but Leaving the Door Open for Power Sector GHG Regulations

CleanLaw–Jody Freeman and Richard Lazarus on West Virginia v. EPA, What’s Next?

CleanLaw – Carrie Jenks and Kevin Poloncarz on the Petitions to the Supreme Court of the D.C. Circuit’s decision vacating the Affordable Clean Energy Rule

Timeline of Events

Obama administration
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New and Existing EGUs: Dec. 7, 2009 EPA released its “Endangerment Finding” that GHGs are a threat to human health and welfare and the agency begins the process of rulemakings to regulate GHG emissions.

New EGUs: Oct. 23, 2015 EPA published a final rule setting limits on CO2 emissions from new, modified, and reconstructed power plants. North Dakota challenged the rule on the same day. North Dakota v. EPA, Case No. 15-1381 (D.C. Cir.).

Existing EGUs: Oct. 23, 2015 EPA published the Clean Power Plan (or the “Carbon Pollution Emission Guidelines for Existing Stationary Sources: Electric Utility Generating Units”). This final rule set carbon pollution limits on existing power generators. Some states and industry groups immediately challenged the rule in the DC Circuit Court. West Virginia v. EPA, Case No. 15-1363 (D.C. Cir.).

Existing EGUs: Feb. 9, 2016 The Supreme Court stayed the Clean Power Plan to keep it on hold through review at the DC Circuit and through review at the Supreme Court if it is appealed and accepted. Many have noted that at the time, this response by the Supreme Court to stay the rule before any court ruled on the merits was very unusual.

Trump Administration
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New and Existing EGUs: March 28, 2017 President Trump signed the Executive Order on Promoting Energy Independence and Economic Growth, directing EPA to review and “if appropriate . . . publish for notice and comment proposed rules suspending, revising, or rescinding” the Clean Power Plan and NSPS rule. EPA asked the DC Circuit to pause the litigation while it reviewed the CPP. West Virginia v. EPA, Case No. 15-1363 (D.C. Cir.). EPA also requested that the DC Circuit delay oral argument and suspend the litigation for the NSPS. North Dakota v. EPA, Case No. 15-1381 (D.C. Cir.).

New EGUs: March 30, 2017 The court agreed to suspend oral argumentNorth Dakota v. EPA, Case No. 15-1381 (D.C. Cir.).

New EGUs: April 4, 2017 EPA published its intent to review the NSPS rule.

Existing EGUs: April 28, 2017 At the request of the Trump Administration, the DC Circuit suspended West Virginia v. EPA litigation for 60 days and ordered EPA to file 30-day status reports on the agency’s review of the rule. The court also asked the parties to file briefs to address whether the rule should be returned to EPA in lieu of continued suspension of the litigation. West Virginia v. EPA, Case No. 15-1363 (D.C. Cir.).

New EGUs: April 28, 2017 The DC Circuit put the litigation on hold for 60 days and ordered EPA to file 30-day status reports. North Dakota v. EPA, Case No. 15-1381 (D.C. Cir.).

Existing EGUs: May 15, 2017 EPA filed a brief arguing WV v. EPA should remain suspended to preserve the Supreme Court’s stay. Environmental groups sought a remand to EPA to lift the stay and require the agency to go through a rulemaking process to repeal the Clean Power Plan. The states and environmental groups supporting the CPP also asked the DC Circuit to rule on the merits of the case, arguing the same issues will reappear in any new rule issued under this section of the Clean Air Act. West Virginia v. EPA, Case No. 15-1363 (D.C. Cir.).

Existing EGUs: Aug. 8, 2017 The court agreed to continue to pause the litigation in WV v. EPA for another 60 days. Judges Millett and Tatel concur in the order but added that “[a]s this court has held the case in abeyance, the Supreme Court’s stay now operates to postpone the application of the Clean Power Plan indefinitely while the agency reconsiders and perhaps repeals the Rule… Combined with this court’s abeyance, the stay has the effect of relieving EPA of its obligation to comply with that statutory duty for the indefinite future.” West Virginia v. EPA, Case No. 15-1363 (D.C. Cir.).

New EGUs: Aug. 10, 2017 The DC Circuit suspended litigation indefinitely and ordered EPA to file 90-day status reports beginning Oct. 27, 2017. North Dakota v. EPA, Case No. 15-1381 (D.C. Cir.).

Existing EGUs: Oct. 10, 2017 EPA proposed to repeal the Clean Power Plan, stating the rule “exceeds the Agency’s statutory authority.” EPA indicated it will issue an Advanced Notice of Proposed Rulemaking to solicit comments on carbon control measures that could be implemented at individual power plants.

Existing EGUs: Dec. 28, 2017 EPA published an Advance Notice of Proposed Rulemaking to solicit comments on carbon dioxide emissions control measures that could be implemented at individual power plants.

Existing EGUs: Aug. 21, 2018 EPA announced the proposed replacement rule for the Clean Power Plan, the Affordable Clean Energy (ACE) Rule. The ACE rule included several components: a determination of the best system of emission reduction for greenhouse gas emissions from coal-fired power plants limited to modifications that can be made “within the fenceline” of each plant, a list of “candidate technologies” states can use when developing their plans, a proposed change to the New Source Review (NSR) program: a new applicability test based on hourly emissions for determining whether a physical or operational change made to a power plant may be a “major modification” triggering NSR, and new implementing regulations for emission guidelines under Clean Air Act section 111(d).

New EGUs: Dec. 6, 2018 EPA released proposed revisions to the 2015 GHG New Source Performance Standards for Power Plants. The proposal changed EPA’s determination of best system of emission reduction (BSER) for newly constructed coal-fired units. It replaced partial carbon capture and storage with steam cycle in combination with operating practices as BSER.

Existing EGUs: June 19, 2019 EPA released the final ACE Rule along with the final repeal of the Clean Power Plan. Read our analysis of the ACE rule.

Existing EGUs: Summer/Fall 2019 Several organizations and states filed petitions challenging the ACE Rule in the DC Circuit. Industry groups also challenged EPA’s authority to regulate carbon dioxide emissions in the ACE Rule and states and cities intervened to support EPA’s authority to regulate carbon dioxide emissions from fossil-fueled power plants. All consolidated in American Lung Association v. EPA, Docket No. 19-1140 (D.C. Cir.).

Existing EGUs: Sep. 17, 2019 The DC Circuit dismissed the Clean Power Plan case as moot, meaning there is no longer an active case because the Clean Power Plan has officially been repealed. West Virginia v. EPA, Case No. 15-1363 (D.C. Cir.).

New EGUs: Jan. 13, 2021 EPA finalized its rule that required the agency to make a pollutant-specific significant contribution finding for newly constructed coal-fired units. EPA had not previously considered pollutant-specific significant contribution findings necessary reasoning that the agency makes a finding of significant contribution for the source category when it lists it. The final rule also established a new threshold of 3 percent of total US GHG emissions for finding that sources contribute significantly to dangerous air pollution due to their GHG emissions. Applying this threshold, the agency concluded the units’ GHG emissions contribute significantly. The agency also introduced the requirement of a pollutant-specific significant contribution finding in its oil and gas GHG standards rule (read more about that here). The final action did not include the Dec. 20, 2018 proposal to change the best system of emission reduction (BSER).

Existing EGUs: Jan. 19, 2021 The DC Circuit struck down the ACE rule, remanding it to the agency, explaining that “EPA rewrites rather than reads the plain statutory text.”

Biden Administration
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New EGUs: Jan. 20, 2021 President Biden’s Executive Order 13990 required EPA to consider suspending, revising, or rescinding the Jan. 2021 final significant contribution rule establishing a 3 percent threshold of total US GHG emissions before regulation of a new, modified, or reconstructed source is warranted.

Existing EGUs: Feb. 22, 2021 The DC Circuit stayed its mandate vacating the Clean Power Plan Repeal Rule to allow EPA to respond with a new rulemaking to avoid confusion about what rule was in place, making clear that the Clean Power Plan was not revived by the decision.

New EGUs: March 17, 2021 EPA asked the DC Circuit to vacate the Jan. 13, 2021 significant contribution rule for newly constructed coal-fired units due to procedural defects and requested that the court remand it to the agency. California v. EPA, 21-1035 (D.C. Cir.).

New EGUs: Apr. 5, 2021 The DC Circuit vacated and remanded to EPA the Jan. 2021 significant contribution rule. California v. EPA, 21-1035 (D.C. Cir.).

Existing EGUs: April 2021 A group of states led by West Virginia, as well as several companies petitioned the Supreme Court asking that it address whether section 111(d) of the Clean Air Act allows for the type of generation shifting envisioned in the Clean Power Plan, arguing the decision vacating the ACE rule improperly attributed wider authority to the agency than Congress intended. West Virginia, et al., Petitioners vs. Environmental Protection Agency, et al., Docket No. 20-1530 (U.S. May 4, 2021).

Existing EGUs: Aug. 5, 2021 The Biden administrationstatesNGOs, and power companies filed briefs opposing the petitions for a writ of certiorari.

Existing EGUs: Oct. 29, 2021 The Supreme Court granted the petitions for writ of certiorari on the section 111 statutory interpretation questions presented by the petitioners related to the major questions doctrine, whether Congress authorized EPA to set a standard that accounts for measures that reduce emissions from the electric system, including generation shifting and cap-and-trade programs, and whether EPA’s standard limits measures states may include in their compliance plans.

Existing EGUs: June 30, 2022 The Supreme Court held in a 6-3 decision that EPA lacks the authority under Section 111(d) of the CAA to set a cap on GHG emissions from power plants based on generation shifting. The majority reached this holding by applying the major questions doctrine, which it stated requires Congress to provide EPA with clear authorization before forcing a nationwide transition away from coal-fired electric generation. This decision created practical challenges and legal hurdles for the Biden administration in drafting rules to regulate power plant GHG emissions, but it did not strip EPA’s authority to do so, nor did it preclude EPA from considering measures applied outside the fenceline. Read our analysis of the decision here.

New EGUs: Aug. 16, 2022 President Biden signed the Inflation Reduction Act, which expanded tax credits for carbon capture and hydrogen (as a fuel), which changed the cost considerations for these technologies as a potential basis for BSER. Read more about the IRA’s impacts on the power sector here.

New and Existing EGUs: Apr. 21, 2022 EPA released a white paper summarizing control techniques and measures to reduce GHG emissions from stationary combustion turbines. The measures explored include efficiency improvements, integrated renewables, CCUS, and hydrogen.

New EGUs: Dec. 8, 2022 The Environmental Defense Fund (EDF) and the Sierra Club filed a suit against the EPA for failing to update NSPS for new combustion turbines. EPA’s administrator is required to update these standards every eight years, but has not done so in 16 years. EDF and Sierra Club are seeking injunctive relief to compel EPA to issue a final revision of NSPS rule by December 15, 2023 at the latest. Environmental Defense Fund et al v. United States Environmental Protection Agency, Docket No. 3:22-cv-07731 (N.D. Cal. Dec 07, 2022).

Existing EGUs: Dec. 15, 2022 EPA issued its proposed rule for CAA section 111(d) state plan adoption and submittal deadlines.

New and Existing EGUs: May 11, 2023 EPA proposed standards for new gas-fired power plants and existing coal- and gas-fired power plants. See timelines of the proposed rules here: EPA proposes new rules to combat climate changing pollution from power plants.

Existing EGUs:  July 7, 2023 EPA published its Integrated Proposal Modeling and Updated Baseline Analysis Memo that incorporated estimated impacts of the proposed rule for existing combustion turbines.

Existing EGUs: Nov. 9, 2023 EPA issued its final 111(d) implementing regulations for existing sources.

New and Existing EGUs: Nov. 15, 2023 EPA issued a supplemental proposal soliciting comment on reliability mechanisms to include in the final rule and an Initial Regulatory Flexibility Analysis (IRFA) following the completion of a Small Business Advocacy Review (SBAR) panel for the proposed rule.

Existing EGUs: Feb. 29, 2024 EPA announced that it would take a new approach for GHG standards for existing gas-fired power plants that would “cover the entire fleet of natural gas-fired turbines, as well as cover more pollutants including climate, toxic and criteria air pollution.”

Existing EGUs: Mar. 26, 2024 EPA opened a non-regulatory docket and issued framing questions to gather input about ways to design a strong and durable approach to greenhouse gas regulation of existing gas combustion turbines in the power sector under Clean Air Act 111(d). Docket ID EPA-HQ-OAR-2024-0135.

New and Existing EGUs: May 9, 2024 EPA published the final GHG standards for existing coal-fired power plants and new gas-fired power plants. Read our analysis of the rule here: EPA’s Final CO2 Standards for the Power Sector: Robust Regulatory Record Sets the Stage for Legal Challenges

New and Existing EGUs: May/June 2024: States and industry filed petitions in the DC Circuit challenging the rule. All cases were consolidated with West Virginia v. EPA, Docket No. 24-1120 (D.C. Cir. May 9, 2024). States, cities, and industry filed an unopposed motion to intervene in support of EPA.

New and Existing EGUs: May 17, 2024 The D.C. Circuit denied petitioners request for administrative stay and established the following schedule for the briefing of stay motions: any additional motions for stay due May 24th, respondents’ consolidated response to motions for stay due June 11th, and replies in support of motions for stay due June 18thWest Virginia v. EPA, Docket No. 24-1120 (D.C. Cir. May 9, 2024).

New and Existing EGUs: July 2, 2024 Petitioner states filed a 28j letter arguing that the D.C. Circuit should stay EPA’s new rule given the Supreme Court’s recent opinion in Ohio v. EPA. West Virginia v. EPA, Docket No. 24-1120 (D.C. Cir.).

New and Existing EGUs: July 8-10, 2024 EPA and intervening states and cities filed responses to petitioner states’ 28j letter. They contrast EPA’s new rule with the rule at issue in Ohio v. EPA and argue that the petitioner’s stay motions should be denied. West Virginia v. EPA, Docket No. 24-1120 (D.C. Cir.).