The solar-energy business is booming. The average cost of installing solar panels has dropped by half since 2010, and a new solar electric system is now installed somewhere in the United States every four minutes. The growth extends well beyond the rooftops of American homes and small businesses; last week, Apple announced that it is investing in an eight-hundred-and-fifty-million-dollar solar farm in Monterey County, California, which it says will power its operations in the state by the end of 2016. Although solar is still small, supplying less than one per cent of the country’s electricity, its growth has alarmed the energy industry’s old guard—coal, oil, and utility companies. Working primarily through conservative advocacy groups such as the American Legislative Exchange Council (ALEC), which lobbies at the state level, and Americans for Prosperity (A.F.P.), which was founded by Charles and David Koch, the billionaire industrialists, this coalition is doing its best to weaken the nascent industry, particularly rooftop solar. In a curious twist, however, ALEC and A.F.P. have found themselves butting heads with—and even losing battles to—tough-minded, pro-solar branches of the Tea Party.

Debbie Dooley was one of the twenty-two organizers of the first nationwide Tea Party protest, in 2009. A preacher’s daughter from Louisiana, she is a co-founder of the Atlanta Tea Party, on the board of directors of the national Tea Party Patriots, and, since 2012, has been a fierce solar-power advocate. “I thought that the regulated monopoly in Georgia had far too much power,” she told me recently, describing the dominant utility company in her state. “They had begun to look out for the best interests of their stockholders instead of their utility customers.” Solar, she said, promised to give people energy autonomy. “The average person cannot build a power plant, but they can install solar panels on their rooftop, and they should be able to sell that energy to friends and neighbors if they wish.”

Dooley led a fight to persuade Georgia’s all-Republican utility commission to require Georgia Power to buy more of its energy from solar sources. A.F.P. fought back, sometimes in ways that Dooley found troubling. “They would put out completely false information,” she told me. Through mailers, mass e-mails, and Twitter, “they said that adding solar would cause disruption to the power supply and your household appliances. Electricity would be forty per cent higher! I don’t think they were really expecting me to go after what they were saying as forcefully as I did. I just ripped them to shreds over not being factual. We won that battle.” (A.F.P. did not respond to repeated requests for comment.) That was in 2013. Dooley had teamed up with the Sierra Club to form the Green Tea Coalition. Later, that coalition helped defeat an effort by Georgia Power to impose heavy fees on customers with rooftop solar systems.

Dooley and her environmentalist partners have tacitly agreed to disagree about many things, starting with climate change. “That’s something we don’t get involved in,” she said. “If you mention climate change, they’re going to tune you out.” She meant her Tea Party compatriots, of course, with whom she emphasizes, when she talks about solar energy, the free market, consumer choice, and national security. “Rooftop solar makes it harder for terrorists to render a devastating blow to our power grid,” she said. “There’s nothing more centralized in our nation. If terrorists were able to take down nine key substations, it would cause a blackout coast to coast.”

Utility companies are not wrong to fear rooftop solar. Its popularity, if unchecked, will certainly cut into their profits and, perhaps, into their budget for maintaining the electrical grid. Hence an ALEC campaign, revealed by the Guardian last winter, to promote legislation to penalize individual homeowners who use rooftop solar and to label them “free riders.” This effort is part of a broader campaign against renewable energy—solar, wind, biomass—that ALEC, whose leading members include such fossil-fuel giants as ExxonMobil and Peabody Energy, has been conducting for years. In 2012, according to the Guardian, “The group sponsored at least 77 energy bills in 34 states,” many with the goal of blocking renewable-energy efforts and weakening clean-energy regulations. The model legislation developed by ALEC in this area is called, of all things, the Electricity Freedom Act.

Solar is prospering in spite of these efforts, and not only among wealthy liberals in California. According to the Center for American Progress, a liberal think tank, the majority of solar-equipped households in New York and Massachusetts are located in neighborhoods with a median income of between forty and ninety thousand dollars. A recent study by researchers at Yale and the University of Connecticut found that socioeconomic and demographic factors like income, party affiliation, and the unemployment rate had little influence on the spread of residential solar-power systems in Connecticut between 2005 and 2013. The main factor that seemed to drive whether a household installed such a system was whether a neighbor had recently done so.

In Georgia, thanks in part to Dooley’s efforts, the State Senate is likely to pass a bill that will make rooftop solar easier and cheaper for residents to install. (The House just passed it unanimously.) “Georgia is the new sunshine state,” Dooley told me happily. When we spoke, she was driving to the old sunshine state, Florida, which has notably limited options or incentives for solar investors. Dooley is helping lead the launch of a major ballot initiative that would amend that state’s constitution to allow individuals and businesses with solar panels to sell the power that they generate directly to their tenants or neighbors. (Current law permits only utility companies to sell electricity.)

Floridians for Solar Choice, the group behind the initiative, is an inchoate alliance of libertarians, Christian Coalition conservatives, liberal environmentalists, and eighty-five Tea Party groups—Dooley’s people. They need to collect seven hundred thousand signatures by next February to get the measure on the ballot the following November. The stakes in Florida are high, and Dooley and her colleagues expect substantial resistance from the utility companies and their allies. Last fall, however, a Republican pollster found that seventy-four per cent of Floridians support the goals of the ballot measure. “I’ve got other states saying, ‘Please help us,’ ” Dooley told me. “But Florida is ground zero.”