The CEO of the nation’s biggest public utility said Tuesday that the agency isn’t going to reopen coal-fired power plants under President Donald Trump, who has promised a comeback for the downtrodden coal industry.

Tennessee Valley Authority CEO Bill Johnson said he thinks very little will actually change for the federal utility under Trump.

TVA has said it’s on track to cut its carbon emissions by 60 percent by 2020, compared with 2005 levels. By the end of 2018, the utility will have retired five of its original 11 coal-fired power plants.

Trump, meanwhile, has begun repealing President Barack Obama-era environmental regulations aimed at reducing pollution from mining and burning coal. He has promised to repeal and already ordered a review of the Clean Power Plan, Obama’s centerpiece push to curb climate change by limiting carbon dioxide emissions from coal plants.

Johnson said the retirement of many of TVA’s coal plants was the cheapest way to serve customers, which include more than 9 million people in seven southeastern states. Natural gas prices, not regulation, caused the recent downturn for coal, Johnson said.

“Our statutory duty is to produce electricity at the lowest feasible rate,” Johnson said in an interview with The Associated Press. “And when we decided to close the coal plants, that was the math we were doing. We weren’t trying to comply with the Clean Power Plan or anything else. What’s the cheapest way to serve the customer? It turned out to be retiring those coal plants.”

Johnson acknowledged that Trump could try to change the direction of the agency. By May, Trump can fill five of nine TVA board slots to establish a new majority. The U.S. Senate confirms them.

TVA hasn’t had direct discussions with the administration about the agency’s direction or been invited to meet top administration officials yet, Johnson said.

As a federal employee, Johnson said that he cannot comment on Trump’s efforts to peel back U.S. Environmental Protection Agency and other coal-related regulations.

Among those, Trump has moved to end a moratorium on the sale of coal mining leases on federal lands, and he signed a measure to block an Obama-era regulation that aimed to prevent coal mining debris from being dumped into nearby streams.

Johnson said he recalls “cinders falling from the sky” and not being able to see across the street when he lived in Pittsburgh in his younger years.

“If we look at the history of the environment in this country, and whether it’s improved or not since the creation of the EPA, I believe that we can say that it has improved dramatically,” Johnson said.