The Trump administration is expected as soon as this week to unveil a proposal to replace the Clean Power Plan, former President Barack Obama’s signature initiative to combat climate change, with a narrower rule more friendly to industry.

The 2015 Clean Power Plan, which was never implemented because of a Supreme Court stay, required states to reduce carbon dioxide emissions 32 percent below 2005 levels by 2030, by shifting away from coal plants.

It was the pledge that underpinned the U.S.’ commitment to the Paris climate change agreement before President Trump rejected the deal.

In choosing to replace the Clean Power Plan, rather than repeal it outright, the Environmental Protection Agency is acknowledging the federal government is legally obligated to regulate emissions of carbon and other greenhouse gases that cause global warming.

“If they don't do anything about it, the next administration might adopt a worse regulation, so this is checking the box for the coal fleet on carbon regulation in the near-term,” Paul Bailey, president emeritus and former CEO of the American Coalition for Clean Coal Electricity, told the Washington Examiner.

Trump administration opponents say the EPA is only acting out of legal desperation, and that its proposal would not significantly cut carbon emissions because it would help keep alive coal plants that would otherwise retire.

“We don't think they should limit themselves in the way they are expected to,” said David Doniger, director of the Natural Resources Defense Council’s climate and clean energy program. “It shows a lack of seriousness. The purpose of this plan is not to do nothing. It’s to prop up the coal industry."

The Trump administration argues that Obama based the Clean Power Plan on an overbroad interpretation of the Clean Air Act, and that it would be costly to implement, and have negligible impact on cutting carbon emissions.

Under the rule, the EPA gave each state a target for reducing emissions and encouraged power plants to meet those levels by moving away from coal to natural gas and transitioning to wind and solar power.

Experts and industry officials expect the rewritten rule to regulate power plants individually.

The EPA would mandate heat rate improvements in power plants, enabling them to run more efficiently by burning less coal to produce the same amount of electricity.

The Trump administration is expected to pair that component with reforms to a process known as New Source Review, or NSR. The program forces power plants to undergo new pollution reviews when they upgrade facilities, which operators say is so expensive and time-consuming that it discourages utilities from making efficiency improvements. Under changes sought by the EPA, power plants could make upgrades without triggering those extra reviews.

“We can do these efficiency upgrades we have wanted to do with NSR reform, and that may help the economics of coal units,” Michelle Bloodworth, president and CEO of the American Coalition for Clean Coal Electricity, told the Washington Examiner.

Critics say the benefits of reducing emissions from better efficiency would be overcome by the extra use of a coal plant that should be replaced by a less polluting energy source, such as natural gas.

“The efficiency upgrades would have negligible impact on emissions, or would be downright counterproductive,” Richard Revesz, an environmental law professor at New York University, told the Washington Examiner. “It’s an effort to continue the operation of plants that have been obsolete for decades. There is no economic or environmental justification for doing that.”

EPA is also likely to give more discretion to states to write their own regulations. An unpublished draft of the plan reported by Politico showed that EPA could allow states to opt out of regulating carbon emissions.

Joseph Goffman, a chief architect of the Clean Power Plan who was the lead attorney at the EPA when the Obama administration created the rule, said giving states too much power would be legally dubious.

He says the Clean Air Act only allows states to devise implementation plans to meet carbon emission reduction standards set by the federal government, and does not permit states to set its own rules, or ignore national ones.

“The power system operates on a statewide basis, so it's crazy to create a balkanized system where some states have plans and some states opt out,” Goffman told the Washington Examiner. “We are dealing with a global pollutant. The structure of the Clean Air Act anticipated all of this by not turning everything over to states and mandating EPA set national standards."

Many companies and states are moving away from coal even without a regulation, opting for cheaper natural gas or renewable power because it makes economic sense to do so.

The U.S. is already on pace to meet the Clean Power Plan's emissions reduction goals without it ever taking effect.

Environmentalists say this means the EPA should be acting more ambitiously.

“The underlying problem of carbon pollution is still very present,” Doniger said. “We need to cut carbon pollution much faster than the Clean Power Plan would have done in order to protect ourselves, our kids, and the planet.”

The coal industry also has concerns, recognizing a weaker Clean Power Plan could stave off its death, but fail to help coal stay competitive.

Bloodworth is seeking changes in competitive electricity markets that would reward coal with higher payments because it can store fuel on-site, making it easy to access if the power grid was damaged by weather, or attacked.

Trump has ordered Energy Secretary Rick Perry to use emergency authority to subsidize money-losing coal and nuclear plants.

“Revising the Clean Power Plan is necessary, but not sufficient,” Bloodworth said. “I don't think it will bring back coal, but I would hope it would postpone the impact it has on future retirements.”