Originally published August 24, 2015. Updated September 28, 2026.
The Clean Power Plan was a 2015 EPA rule built to cut carbon dioxide from US power plants roughly 32% below 2005 levels by 2030, but it never got the chance to try. That fight over EPA’s authority is still open, and it decides whether a plant near you answers for its carbon again. The Supreme Court put the rule on hold in February 2016, before any plant had to comply, and EPA repealed it in 2019. The Supreme Court trimmed EPA’s carbon authority further in a 2022 ruling, EPA answered with a tougher standard in 2024, and part of that standard came off the books in a partial repeal taking effect in November 2026.
What the 2015 rule asked states to do
The rule didn’t set one national standard. Picture a coal or gas plant’s smokestack metered against how many megawatts it sends out the other side. That ratio, in pounds of CO2 per megawatt-hour, is what each state’s existing plants had to hit, 1,305 pounds for fossil steam units and 771 pounds for combustion turbines. States could meet those targets with a rate-based limit on pollution per unit of power or convert it into a mass-based cap on total tons, the same basic design behind state carbon-pricing programs.
Compliance was set to run in stages, with interim steps from 2022 to 2029 ahead of a final 2030 deadline, and EPA projected the rule would deliver $25 billion to $45 billion in net climate and health benefits by 2030.
If you lived in one of the 11 states already running a carbon market, like the Northeast’s Regional Greenhouse Gas Initiative, your state had a head start on compliance that others didn’t.
The Supreme Court stopped it before it took effect
EPA published the final rule on October 23, 2015, with an effective date of December 22, 2015. Twenty-four states sued to block it almost immediately, and the fight reached the Supreme Court within months.
On February 9, 2016, the Court stayed the rule while the legal challenge worked through a lower court, with Justices Ginsburg, Breyer, Sotomayor and Kagan noted as dissenting from that order. The rule never applied to a single plant, so if your state had drafted a compliance plan for it, that plan never had to take effect.
EPA swapped it for a narrower rule in 2019
EPA repealed the Clean Power Plan and replaced it with the Affordable Clean Energy rule on June 19, 2019. The new rule dropped the state-by-state targets and the option to shift generation toward gas or renewables across an entire grid, asking existing coal plants instead to improve their own efficiency, one plant at a time. If a coal plant near you kept running past that date, this version left it open. It asked that plant to trim its own carbon a little, plant by plant, instead of switching fuels or shutting down.
That was a much narrower ask than the rule it replaced, and it left the bigger structural question, whether EPA could push utilities to shift generation away from coal at all, for the courts to settle. That same gap, a nationwide generation-shifting target against a plant-by-plant efficiency rule, was at the center of the case the Supreme Court decided three years later.
The Supreme Court curbed EPA’s carbon authority in 2022
The Supreme Court decided West Virginia v. EPA on June 30, 2022, ruling 6-3 that the Clean Power Plan’s generation-shifting approach, moving power generation away from coal and toward gas and renewables across a state’s whole grid, wasn’t authorized by Section 111(d) of the Clean Air Act. The Court invoked the major questions doctrine. Congress has to speak clearly before an agency claims power over a decision this size, the Court said, and it found the statute’s plain text alone wasn’t enough on its own.
Under this law, your utility can’t be forced to swap a coal plant for wind or solar. It can still be told to run that plant more efficiently, the way the rule that replaced the Clean Power Plan already asked it to.
The ruling didn’t touch that narrower 2019 rule directly, since it had already dropped the generation-shifting approach. It closed the door on EPA reviving the Clean Power Plan’s original design without new authority from Congress. Any future rule would have to set standards for equipment at specific plants instead of reshaping the grid as a whole. The rule EPA wrote two years later took exactly that shape.
Biden’s EPA tried a tougher, technology-based rule in 2024
EPA came back two years later, under the Biden administration, with a different, technology-based approach. The agency signed the new rule on April 25, 2024, published it on May 9, and put it into effect July 8, replacing that 2019 rule the same day. Instead of shifting generation across the grid, this one set standards for specific equipment at specific plants.
Existing coal units still expected to run past 2039 had to cut their emission rate 88.4% by January 1, 2032, mainly by capturing 90% of their own carbon, pulling the CO2 out of the exhaust and piping it underground instead of into the sky. Coal units planning to retire before 2039 got an easier path, co-firing 40% natural gas for a 16% emission-rate cut by 2030, and units already set to close before 2032 were exempt. New gas plants built to run nonstop faced that same 90% carbon-capture rule by 2032.
Which deadline applied to the coal plant serving your area came down to that plant’s own retirement plans, and those plans keep changing. For a closer look at how that timeline has played out, see coal decline.
The 32% target got hit years early, without the rule ever running
The reduction the Clean Power Plan promised never had to be forced on anyone. US electric-sector CO2 emissions stood at 2,411.5 million metric tons in 2005, the baseline year the rule used to set its target. By 2019, they had already fallen to 1,617.6 million metric tons, a 32.9% drop that beat the plan’s 32%-by-2030 goal eleven years early, without the rule ever taking effect.
Emissions kept falling from there. By 2024, they were down to 1,427.4 million metric tons, a 40.8% cut from 2005. 2025 brought a 4% increase from the year before, to 1,485.4 million metric tons, but that still left emissions 38.4% below the 2005 baseline.
The rollback in Washington hasn’t undone that. Power plants kept cutting carbon on their own, years ahead of any deadline, while the rule that was supposed to require it never got the chance to work as planned. Whichever rule happened to be on the books at the time, the power coming out of your outlet kept getting a little cleaner regardless.
The finding that gives EPA this power could disappear next
EPA Administrator Zeldin proposed repealing the 2024 rule on June 17, 2025. The proposal argued that power-plant carbon emissions are a small and decreasing part of global emissions and that 90% carbon capture isn’t cost-reasonable for new gas plants to install by the rule’s 2032 deadline.
That proposal became the Partial Repeal of the Carbon Pollution Standards, published in the Federal Register on September 17, 2026 and set to take effect November 16, 2026. It drops the 2024 rule’s existing-source guidelines and its 2032 carbon-capture standard for new gas turbines, while keeping that rule’s efficiency standards for new turbines in place. EPA again called 90% carbon capture not adequately demonstrated and not cost-reasonable, the agency’s own characterization of the technology.
The same day, EPA proposed rescinding the 2015 finding that gives it legal authority to regulate power-plant carbon dioxide, the “significant contribution” finding under the Clean Air Act. If it’s finalized, EPA would give up that authority altogether, for any future rule as well as this one. If you want a say in whether that happens, EPA is taking public comments through November 2, 2026, with a hearing on October 1.
