President Donald Trump’s administration has vowed to revive the coal industry, challenged climate-change science and blasted renewable energy as expensive and dependent on government subsidies.

And yet the solar power industry is booming across Trump country, fueled by falling development costs and those same subsidies, which many Republicans in Congress continue to support.

Data provided to Reuters by GTM Research, a clean energy market information firm, shows that eight of the 10 fastest-growing U.S. solar markets between the second quarters of 2016 and 2017 were Western, Midwestern or Southern states that voted for Trump, with Alabama and Mississippi topping the list. And solar firms are ramping up investments in these regions, signaling their faith that key renewable energy incentives will remain in place for years to come.

The industry’s sunny outlook illustrates the complexity of green power politics in Washington and casts doubt on whether the administration can boost the coal and nuclear sectors while subsidies continue to the fuel growth of competing wind and solar.

Solar expansion in the middle of the country is offsetting its slowing growth in the maturing California and Northeast markets. That marks a big shift for an industry that has historically relied on politically liberal coastal states where renewable energy development is mandated to combat air pollution and climate change.

With falling development costs, solar firms now see strong prospects in conservative states with no such mandates.

“Climate change has never come up in any discussion about why we would do a project,” said Matt Beasley, chief marketing officer for Silicon Ranch Corp, a solar developer based in Nashville, Tennessee. “It is always about the economics.”

The estimated costs of solar power generation have dropped 85% since 2009, making its unsubsidized cost competitive with natural gas in the sunniest locations, according to a report by Lazard, an asset management firm.

Still, the sector’s growth continues to rely on public support. The U.S. Congress’ Joint Committee on Taxation earlier this year estimated that solar projects would receive $12.3 billion in tax breaks between 2016 and 2020.

Trump has never specifically proposed repealing those incentives but has expressed skepticism about the viability of solar and wind, calling both "very, very expensive".

The president’s Energy Secretary Rick Perry last month called for new rules to subsidize coal and nuclear energy, arguing that the rise of weather-dependent solar and wind power would make the grid less reliable.

This week, Environmental Protection Agency chief, Scott Pruitt, said during in a speech in Kentucky that he would scrap incentives for renewable energy firms and let them “stand on their own,” while acknowledging the decision rests with Congress.

A White House official did not respond to a request for comment and clarification of the administration’s position on solar subsidies. But other Republicans are outspoken in their continuing support for the incentives, using an economic rather than environmental rationale.

“The expansion of solar and other clean technologies has created thousands of jobs and reduced emissions,“ said Sen. Richard Burr, a North Carolina Republican. ”Once these technologies have reached a competitive position in the energy market, a gradual reduction in incentives is an appropriate way to approach their sustained growth.”

Of the 10 states that installed the largest amounts of solar power over the past year, six were Republican-led, according to the GTM Research data. Of those, Utah, North Carolina and Texas each installed more than 1 gigawatt of solar, or enough to power about 700,000 homes.

Industry players hope solar growth in states that form Trump’s political base will influence how he decides later this year in a trade case they fear could lead to tariffs on solar panels imported to the U.S.