In federal policymaking, the weight of the law can rest on a single word. When it comes to reducing planet-warming emissions from the power sector, that word is “significantly.” The Clean Air Act requires the Environmental Protection Agency to regulate any stationary source of emissions that “causes, or contributes significantly to, air pollution which may reasonably be anticipated to endanger public health or welfare.”
The EPA has considered power plants a significant source of dangerous greenhouse gases since 2015. But today, Trump’s EPA said, actually, never mind.
A proposed rule published in the Federal Register on Wednesday argues that U.S. fossil fuel-fired power plants make up “a small and decreasing part of global emissions” and therefore are not significant, and do not require regulation under the law. The rule would repeal all greenhouse gas emission standards for new and existing power plants — both the standards the Biden administration finalized last year, which have been tied up in court, as well as the standards that preceded them, which were enacted by Obama in 2015.
In a separate proposal, the EPA also took steps to repeal limits on mercury and hazardous air pollutants from coal plants that were enacted last year, reverting the standard back to one set in 2012.
The argument that U.S. power plants make up a small sliver of global emissions and thus aren’t worth addressing is like having “a five-alarm fire that could be put out if you send out all the trucks, and you don’t send any of the trucks because no one truck could put the fire out by itself,” David Doniger, a senior attorney and strategist at the Natural Resources Defense Council, told me. “We just think that is a wacky reversal and a wacky interpretation of the Clean Air Act.”
When you add up every plug, power button, and light switch across the country, electricity usage produces 25% of U.S. greenhouse gas emissions each year. Over the past 30 years, American power plants have contributed about 5% of the total climate pollution spewed into the atmosphere worldwide.
In the global context, that may sound small. But in a recent report titled “The Scale of Significance," New York University’s Institute for Policy Integrity estimated that if U.S. power plants were a country, it would be the sixth biggest emitter in the world, behind China, the European Union, India, Russia, and the remainder of U.S. emissions. The report also notes that U.S. actions on emissions make other countries more likely to follow, due to technological spillovers that reduce the cost of decarbonization globally.
The Technical Argument
In addition to the significance finding, the EPA gave two other reasons for repealing the power plant rules. It argued that “cost-effective control measures are not reasonably available,” meaning there’s no economic way to reduce emissions at the source. It also said the new administration’s priority “is to promote the public health or welfare through energy dominance and independence secured by using fossil fuels to generate power.”
The first argument is an attempt to say that Biden’s standards flouted the law. In 2022, the Supreme Court ruled that the EPA could not simply tell states to reduce emissions from the power sector, which is what the Obama administration had initially tried to do. Instead, the agency would have to develop standards that could be applied on a plant-by-plant basis — so long as those rules were “cost-reasonable” and “adequately demonstrated.”
To comply with that ruling, Biden’s EPA based its standards on the potential to install carbon capture technology that can reduce flue gas emissions by 90%. The regulations would have required existing coal plants to install carbon capture by 2039, or else shut down. (To the chagrin of many energy system observers, the administration chose not to apply limits to existing gas-fired power plants.) But while fossil fuel companies and utilities had, in the past, asserted that carbon capture was viable, they deemed the standards impossible to meet.
Trump’s EPA is now agreeing. “In 2024,” Zeldin said on Wednesday, “rules were enacted seeking to suffocate our economy in order to protect the environment, to make all sorts of industries including coal and more disappear, regulate them out of existence.”
The Long Game
When Trump moved to overturn Obama’s power plant regulations during his first term, his EPA did not contest the significance of the sector’s emissions, and simply enacted a weaker standard. A week before he left office, the agency also finalized a rule that set the threshold for “significance” at 3% of U.S. emissions — which exempted major polluters like refineries, but still applied to power plants.
This time, Trump has a new apparent game plan: Strip the Clean Air Act of its jurisdiction over greenhouse gases altogether. Today’s action was the first step; EPA Administrator Lee Zeldin has said the agency will similarly “reconsider” emissions rules for cars and oil and gas drilling. But the cornerstone of the plan is to reverse what’s known as the “endangerment finding” — the 2009 conclusion that greenhouse gases present a threat to public health and welfare, and therefore are one of the pollutants EPA must address under the Clean Air Act.
“The Trump administration is trying to say, don’t worry about the Clean Air Act. It will never apply, so you can go back to your old ways,” said Doniger. But if the argument that power plant emissions are insignificant is a stretch, appraising greenhouse gas emissions as benign is inconceivable, he said. “The endangerment finding was based, in 2009, on a Denali-sized mountain of evidence. Since then, it’s grown to Everest-size, so there’s no way that they would be able to put together a rational record saying the science is wrong.”
The Chevron Trap
These highly technical questions of whether emissions are “significant” or whether carbon capture is “adequately demonstrated” could soon be determined by a group of people who lack both the expertise to answer them and the inclination to wade through thousands of pages of atmospheric science and chemical engineering documents: judges.
Last year, the Supreme Court overturned a long-held precedent known as Chevron deference. That ruling means that the courts are no longer required to defer to an agency’s interpretation of statute — judges must make their own determinations of whether agencies are following the intent of the law.
When environmental groups begin challenging the EPA’s repeals in court, judges are “going to be bombarded with the need to make these highly technical, nuanced decisions,” Michael Wara, a lawyer and scholar focused on climate and energy policy at Stanford University, told me. He said the reason Chevron deference was established in the first place is that judges didn’t want to be making engineering decisions about power plants. “They felt extremely uncomfortable having to make these calls.”
The conservative Supreme Court overturned the precedent because of a sense that political decisions were being dressed up in scientific reasoning. But Wara doesn’t think the courts are going to like being put back into the role of weighing technical minutia and making engineering decisions.
“It’s a past that the courts didn’t like and they tried to engineer a way out of via the Chevron doctrine,” he said. “I would expect that we’re going to see a drift back toward a doctrine that looks a little bit more Chevron-like, maybe less deference to agencies. But it’s hard to predict in the current environment what’s going to happen.”
A chart showing which manufacturers are providing the turbines for America's gas projects. GEM