EPA’s signed final rule repeals key portions of the 2024 Carbon Pollution Standards for existing steam plants, certain coal-unit modifications and new baseload turbines, while a separate proposal seeks comment on repealing the remaining power-plant greenhouse-gas rules.
Published by Allstream Insiders
Allstream Insiders Summary
The U.S. Environmental Protection Agency signed a final partial repeal of the 2024 Carbon Pollution Standards for fossil fuel-fired power plants on September 14, 2026, while separately proposing to rescind the remaining greenhouse-gas standards for the sector under Clean Air Act Section 111.
The final action repeals the 2024 emission guidelines for existing coal-, oil- and gas-fired steam generating units; carbon-capture-and-storage-based requirements for coal-fired steam units undertaking a large modification; and the Phase 2 carbon-capture-based standards for new baseload stationary combustion turbines.
The final action is a partial repeal, not a complete elimination of all power-plant greenhouse-gas standards. EPA did not revise or repeal the 2024 efficiency-based Phase 1 standards for new stationary combustion turbines in this final rule. Those and other remaining standards are addressed in the separate proposal, which remains subject to public comment and a future final action.
EPA’s signed prepublication rule states that the final action will become effective 60 days after publication in the Federal Register. The agency’s September 14 online version is not itself the official Federal Register version for compliance purposes.
What has EPA finalized?
EPA finalized the repeal of several requirements adopted in the 2024 Carbon Pollution Standards after reevaluating the statutory “best system of emission reduction” determinations underlying those requirements.
| 2024 requirement | Status under EPA’s September 2026 final rule |
|---|---|
| Emission guidelines for existing fossil fuel-fired steam generating units | Repealed in their entirety, covering existing coal-, oil- and gas-fired steam units |
| CCS-based standards for coal-fired steam units undertaking a large modification | Repealed |
| Phase 2 CCS-based standards for new baseload stationary combustion turbines | Repealed |
| 2024 efficiency-based Phase 1 standards for new stationary combustion turbines | Remain in place under this final action |
EPA concluded that 90% carbon capture and storage was not adequately demonstrated or cost-reasonable as the best system of emission reduction for the affected coal and new baseload turbine categories. The agency also concluded that 40% natural-gas co-firing was not the best system of emission reduction for existing medium-term coal-fired steam units.
What is still only proposed?
EPA has issued a supplemental proposal, rather than a final rule, that would repeal the remaining greenhouse-gas standards for fossil fuel-fired electric generating units under Clean Air Act Section 111.
The proposal covers the remaining partial-CCS-based standards for new and efficiency-based standards for reconstructed or modified steam generating units and integrated-gasification-combined-cycle facilities, as well as efficiency-based standards for new or reconstructed stationary combustion turbines.
EPA’s proposal advances the agency’s legal interpretation that Section 111 does not authorize regulation of power-plant greenhouse-gas emissions in response to global climate-change concerns. That is EPA’s proposed position; it would have no legal effect unless and until the agency completes the proposal with a final rule.
When do the final rule and proposal take effect?
The signed final partial-repeal rule is scheduled to take effect 60 days after Federal Register publication. EPA has indicated that the official Federal Register version will replace its September 14 prepublication document once published.
The supplemental proposal has a separate process. EPA said it will hold a virtual public hearing 15 days after the proposal is published in the Federal Register and keep the public-comment period open for 45 days after publication. The proposal does not change applicable requirements unless EPA issues a later final rule.
Which power plants are covered?
The rulemaking addresses fossil fuel-fired electric utility steam generating units and stationary combustion-turbine electric generating units that provide electricity to the grid. EPA identifies the affected source category with NAICS code 221112 as a guide, while noting that the code is not intended to be exhaustive.
What does EPA’s $310 billion figure represent?
EPA estimates approximately $310 billion in present-value social-cost savings from the final partial repeal between 2026 and 2047, expressed in 2024 dollars and discounted to 2025. The figure is EPA’s model-based estimate, not a direct forecast of retail electricity-bill reductions for individual customers.
In the final-rule preamble, EPA distinguishes this modeled social-cost figure from estimated power-sector compliance-cost savings and real-resource-cost savings. The agency also states that its model does not account for changes in environmental quality resulting from the action.
Allstream analysis: What should power-sector participants do differently?
For owners, developers and suppliers, the immediate takeaway is to separate the signed partial repeal from the broader proposal. The final action removes specified 2024 requirements on its stated effective-date schedule; it does not by itself eliminate every Section 111 greenhouse-gas requirement for fossil fuel-fired power plants.
Teams evaluating natural-gas generation, coal-unit modifications, carbon-capture systems, power-plant engineering and related infrastructure should track the Federal Register publication, the proposal docket and any subsequent final agency action. Project-specific permitting, state requirements and other federal obligations remain separate compliance considerations.
