LOS ANGELES (Reuters) - 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.

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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 percent 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”.

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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, Trump’s 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 Apple One 4.9 MW solar project, built by Cypress Creek Renewables, is pictured in Newton, North Carolina, United States in this undated handout photo obtained by Reuters March 28, 2017. Cypress Creek Renewables/Handout via REUTERS

“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 yar in a trade case they fear could lead to tariffs on solar panels imported to the U.S.

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SOLAR SUPPORT IN TRUMP COUNTRY

Solar and wind energy firms have become important constituents in some Republican-led states because they employ about 300,000 people nationwide - six times the number working in the coal industry, according to industry and government data.

In 2015, a Republican-controlled Congress extended lucrative tax credits for renewable energy industries through 2020, primarily a tax credit worth 30 percent of the cost of residential and utility-scale installations.

Under current law, the solar credits would phase out gradually, ending at a permanent 10 percent for utility projects after 2021. The residential credit would expire. Solar firms expect that, by then, they can bring down costs enough to compete without government help.

Solar providers in rural states have also gotten a boost from a pair of other federal programs.

One is a U.S. Department of Agriculture program ushered in by former President Barack Obama, which provided more than $400 million in funding for rural solar projects in 2015 and 2016. Seventy percent of the money went to states that voted for Trump.

The other is the federal Public Utility Regulatory Policies Act (PURPA), a 40-year-old law requiring utilities to buy renewable power from small providers if their prices are competitive with fossil fuels - something solar developers have only recently been able to offer.

The growth of solar directly undermines Trump’s goal of boosting the coal industry. Luke Popovich, a spokesman for the National Mining Association, called Republican support of solar subsidies “inconsistent with market-based energy policy.”

“Solar is a competitor - and a handsomely subsidized one, along with wind,” he said.

House of Representatives Republican Majority Leader Kevin McCarthy, of California, has supported such incentives but said clean power firms should soon start fending for themselves.

“It’s not a level playing field,” McCarthy told Reuters in an interview. “So you will see those (subsidies) beginning to phase out.”

BOON TO DEVELOPERS

Beyond subsidy politics, solar developers’ confidence in red-state markets reflects strong demand from utilities there.

When Reuters surveyed 32 utilities with operations in politically conservative states earlier this year, they overwhelmingly rejected making new investments in coal-fired power despite Trump’s pro-coal agenda - citing falling costs of renewable energy as a factor.

In one example last month, Ameren Corp's AEE.N coal-dependent Missouri utility said it would add 100 megawatts of solar in the next decade.

One installer benefitting from solar’s geographic shift is Inovateus Solar LLC, based in South Bend, Indiana. Eighty percent of its planned project pipeline is in either its home state or neighboring Michigan.

“A red state like Indiana has a lot to show the current administration on how solar energy is valuable and economical,” said Inovateus Chief Executive TJ Kanczuzewski.

Vermont-based groSolar, a subsidiary of France's EDF EDF.PA, just opened a Minnesota office and called the Midwest its "number one priority" for future development.

“There’s been a groundswell of interest and curiosity from utilities,” she said. “We’re anxious to fill that need.”

Coronal Energy, a California developer backed by Panasonic 6752.T, meanwhile, is targeting electric cooperatives, many of which are in rural states, according to Danny Van Clief, the company's chief commercial officer.

Solar capacity at co-ops, which are not-for-profit utilities owned by their customers, has tripled in the last three years, according to the National Rural Electric Cooperative Association.

Texas, where Energy Secretary Perry was once governor, is expected to be the second biggest state for solar growth over the next five years, according to the Solar Energy Industries Association, largely because of demand from electric cooperatives and municipal utilities, according to Colin Smith of GTM Research.

The wide open spaces of Texas and other states where solar is growing offer cheaper real estate and easier permitting for solar installations than the industry’s traditional markets in densely populated coastal cities, said Silicon Ranch Co-founder Reagan Farr.

“The math works quite well,” he said.