On September 14, 2026, the Environmental Protection Agency (“EPA”) finalized a partial repeal (“Final Rule”) of the 2024 Carbon Pollution Standards (“CPS”) for greenhouse gas emissions (“GHG”) from fossil fuel-fired electric generating units (“EGUs”). The Final Rule strikes most of the emission restrictions from the 2024 CPS and rejects the agency’s prior findings. Concurrent with the Final Rule, the EPA issued a proposed rule to rescind all remaining GHG emissions standards for power plants grounded on a lack of authority to regulate GHG emissions from EGUs under Section 111 of the Clean Air Act (“CAA”).
Justification Behind the Final Rule
The 2024 CPS guidelines originate from 2015, when the EPA promulgated new source performance standards (“2015 NSPS”) and emission guidelines under the Clean Power Plan (“2015 CPP”), aiming to regulate GHG emissions from both new and existing fossil fuel-fired power plants in response to global climate change concerns. Following the United States Supreme Court’s decision in West Virginia v. EPA that the emission restrictions went beyond the agency’s authority under the CAA, the EPA created new GHG emission regulations through the 2024 CPS issued on April 25, 2024. The 2024 CPS was premised, in part, on agency findings that the best system of emission reduction (“BSER”) for both long-term and medium-term fossil fuel-fired EGUs was requiring carbon capture and sequestration/storage (“CCS”) of carbon dioxide emissions.
In the Final Rule, the EPA reevaluated the record and prior determinations of BSER in the 2024 CPS and found that the agency’s prior findings on compliance feasibility and cost implications had “not been adequately demonstrated.” Specifically, the EPA made four separate findings to support its decision that most of the 2024 CPS emission restrictions and associated standards of performance are unachievable and unreasonable: (1) 90 percent CCS is not the BSER for existing long-term coal steam generating units; (2) 40 percent natural gas co-firing is not the BSER for medium-term coal-fired steam generating units; (3) requiring States to submit plans for oil and natural gas-fired steam generating units is imprudent; and (4) 90 percent CCS is not BSER for new base load combustion turbines.
The Final Rule stated that the technical challenges, along with the cost of expanding necessary infrastructure, made compliance with the 2024 CPS regulatory deadlines “highly unlikely, if not impossible.” Therefore, the EPA determined that the vast majority of the 2024 CPS was not reasonable and not achievable.
Impact of the Final Rule
The Final Rule specifically repeals three primary components of the 2024 CPS. First, the Final Rule repeals GHG emission guidelines for existing fossil fuel-fired steam generating units, including 90 percent CCS and 40 percent natural gas co-firing requirements for long-term coal-fired and medium-term coal-fired units respectively.
Second, the Final Rule rescinds the CCS-based standards of performance for coal-fired steam generating units that undertake a large modification. The EPA finds that such 90 percent CCS requirements are not an “adequately demonstrated system of emission reduction” and mandate unreasonable costs onto generators.
Finally, the Final Rule repeals the Phase 2 CCS-based standards for new base load stationary combustion turbine EGUs. This finding is based on the same reasons as rescinding the standards of performance for coal-fired steam generating units that undertake a large modification. Notably, however, the final rule does not annul the Phase 1 CCS-based standards of performance for new base load stationary combustion turbines.
Appeal. On September 17, 2026, shortly following the issuance of the Final Rule, several environmental and public health organizations filed a petition for review with the U.S. Court of Appeals for the District of Columbia challenging the validity of the Final Rule.
Proposed Rule
In a concurrent action with the September 2026 Final Rule, the EPA also published a supplemental notice of proposed rulemaking (“Proposed Rule”) aiming to rescind all remaining GHG regulations for EGUs under Section 111 of the CAA. Unlike the final rule, the EPA is supporting the Proposed Rule on the grounds that the agency lacks authority to regulate GHG emissions for EGUs in the first place when done in response to global climate change under Section 111. Specifically, the EPA seeks public comment to determine the threshold legal question of whether emissions from EGUs which lead to concerns about global climate change are sufficiently considered to “reasonably be anticipated to endanger public health and welfare” under Section 111(b)(1)(A) of the CAA.
The EPA is hosting a virtual public hearing regarding the Proposed Rule on October 1, 2026. The last day to pre-register to speak at the hearing is September 29, 2026.
Comments on the Proposed Rule are due on or before November 2, 2026 (45 days from the September 17, 2026 posting of the Proposed Rule in the Federal Register).
For more information, please contact Bhaveeta K. Mody, Sean M. Neal, Peter J. Scanlon, and Andrea I. Sarmentero Garzón.
Article By DWGP Law Clerk Griffin Krawitz