EPA Power Plant & Emissions Compliance Brief
Headline
EPA proposes to rescind statutory authority for all power plant greenhouse gas regulation under Clean Air Act Section 111
Executive Summary
The EPA published a supplemental proposed rulemaking on September 17, 2026, proposing that Clean Air Act Section 111 does not authorize regulation of power plant greenhouse gas emissions. The proposal would rescind the agency's 2015 endangerment-equivalent findings and repeal all associated 2015 and 2024 greenhouse gas standards for fossil fuel-fired electric generating units.
Bottom Line
The proposal removes the legal foundation for all EPA greenhouse gas regulation of fossil fuel-fired power plants under Section 111, not merely the specific standards already repealed by the concurrent final rule. Fossil fuel-fired electric generating unit operators face two simultaneous regulatory actions: a final rule eliminating certain 2024 standards now, and this supplemental proposal that, if finalized, eliminates the statutory basis for any future greenhouse gas standard under this authority. The 2015 administrator findings, which have served as the administrative predicate for every subsequent power sector greenhouse gas rule, are proposed for rescission. The concurrent final rule's repeal of certain 2024 standards stands independently and is not affected by the outcome of this supplemental proceeding.
Key Regulatory Signals
- Statutory Authority Withdrawn at the Root: The EPA proposes that Section 111 of the Clean Air Act provides no legal basis for regulating greenhouse gas emissions from power plants in response to climate change. This is not a technical revision to existing standards; it is a proposed elimination of the legal foundation on which all prior power sector greenhouse gas rules rested.
- 2015 and 2024 Standards Both Targeted: The proposal covers the rescission of the 2015 administrator findings and the repeal of all associated 2015 and 2024 greenhouse gas emission standards for fossil fuel-fired electric generating units. A concurrent final rule has already repealed certain 2024 standards on separate legal and technical grounds; this supplemental action addresses the broader statutory question.
- Concurrent Final Rule Operates Independently: The EPA finalized repeal of certain 2024 greenhouse gas standards in a separate action published the same day. That final rule is not reopened by this supplemental notice, and comment on those issues is not solicited here except where commenters believe it bears on the distinct statutory-authority questions raised.
- Compliance Posture for Regulated Generators Shifts: Fossil fuel-fired electric generating unit operators currently subject to the 2024 standards face a bifurcated regulatory landscape: the concurrent final rule removes certain 2024 obligations now, while this supplemental proposal, if finalized, would eliminate the remaining statutory predicate for any future greenhouse gas standard under this authority.
- Comment Period Opens on Statutory Question: The supplemental notice solicits public comment specifically on whether Section 111 authorizes EPA greenhouse gas regulation for power plants and on the proposed rescission of the 2015 findings. The concurrent final rule's distinct grounds are outside the scope of this comment period.
Regulatory Delta
- This proposal goes beyond the concurrent final rule by targeting the statutory authority itself. That is a structural departure from prior EPA rulemaking posture, under which Section 111 has been treated as a valid vehicle for greenhouse gas regulation since at least 2015.
- The proposed rescission of the 2015 administrator findings removes the administrative predicate that has anchored every subsequent power sector greenhouse gas standard, including the 2024 rule.
- The Supreme Court's 2022 decision in West Virginia v. EPA constrained EPA's authority to mandate grid-wide generation shifting, but left Section 111 facility-level regulation intact. This proposal goes further, contesting the authority to regulate power plant greenhouse gas emissions at all.
Materiality Classification
HIGH — This supplemental proposed rulemaking contests the statutory authority underlying all EPA greenhouse gas regulation of fossil fuel-fired power plants, requiring electric generators, utilities, and their counterparties to reassess compliance obligations and long-term capital planning against a bifurcated and actively shifting regulatory baseline.
Intelligence Outlook
Monitor the EPA Federal Register docket for this supplemental rulemaking for the comment-period close date, any final rule publication, and any judicial challenge filings in federal circuit courts.