The US Environmental Protection Agency (EPA) has revealed its long-promised plan to relax federal limits on greenhouse-gas emissions from power plants. The proposal, announced on 21 August, takes direct aim at former president Barack Obama’s flagship climate regulation, the Clean Power Plan. But the new EPA plan faces stiff opposition from scientists, environmentalists and many progressive states.

The EPA proposal would give states leeway to set their own emissions-reduction goals. It emphasizes the use of energy-efficiency technologies that can be applied at the scale of individual power plants.

By contrast, the Obama rules , released in 2015, sought to reduce CO ₂ emissions from the power sector to 32% below 2005 levels by 2030. The plan would have required states and utility companies to collectively reduce emissions by promoting energy efficiency, renewables and other low-carbon energy technologies.

“The era of top own one-size fits all federal mandates is over,” the EPA’s acting administrator, Andrew Wheeler, said at a 21 August press conference. He added that the proposal — dubbed the Clean and Affordable Energy plan — would continue to drive down emissions.

Facing challenges

Environmentalists argue that the EPA is blocking meaningful climate regulations by taking the narrowest possible view of its authority to regulate greenhouse gases. If President Donald Trump’s proposal survives the inevitable legal challenges, it will replace the Clean Power Plan, which the US Supreme Court blocked from implementation in 2016 pending a legal review. The plan has been mired in federal courts since.

The Trump administration wants to "leave a burning wreckage of the Clean Air Act behind them" when they go, says David Doniger, an attorney with the Natural Resources Defense Council, an activist group in New York City. “Our goal is to stymie these rollbacks and protect the EPA’s authority so that we can get back on track after President Trump.”

Doniger and others say that before the Supreme Court blocked the Clean Power Plan, the country was on track to meet or exceed the plan’s goals with minimal economic impact. The progress was due in part to existing trends towards cleaner energy sources in the power sector. As of 2017, CO ₂ emissions from the sector were already down by nearly 28% from 2005 levels, according to the US Energy Information Administration, a federal agency that tracks energy trends.

Economic impacts

Research by Resources For the Future (RFF), an environmental think tank in Washington DC, suggests that the Obama-era regulations would have increased the average price that consumers pay for electricity by just 1%. But the Clean Power Plan would have had more significant economic impacts on regions that still depend heavily on coal mining and coal-fired electricity, such as Appalachia and the parts of the Midwest.

“That’s what is really driving the political debate,” says Dallas Burtraw, an economist with the RFF.

He says the proposed rules will have a minimal impact on CO ₂ emissions. Utility companies might be able to boost the efficiency of any given power plant by a few per cent, which could bring down the price of coal-fired power. This could ultimately increase emissions if energy from coal-powered plants displaced that provided by natural gas and renewables. The upshot, Burtraw says, is that national emissions from electricity generation could decrease by as little as 1.5% from current levels.

The EPA will accept public comments on the draft rule for 60 days before finalizing the proposal.