When Lieutenant Colonel Joseph Goana takes off in his T-38 Talon training jet, he flies a loop north toward the Red River, which forms a meandering border between north Texas and southern Oklahoma. For decades, the remote farming area has been an ideal training ground for Air Force pilots like Goana. But in recent years, he says, there’s been a new obstacle: wind turbines that now generate a third of Oklahoma’s electricity and 17 percent of the power in Texas.

"We need the space above the ground unimpeded so we can fly low to the ground," says Goana, commander of the 80th Training Wing at Sheppard Air Force Base. "Sort of like driver’s ed."

A year ago, military leaders at Sheppard joined state officials to beat back a proposed wind farm in nearby Oklahoma. But base officials now worry about more proposed wind farms that keep cropping up. They say they have been forced to close three of 12 low-flying training routes in the past decade because of “wind farm encroachment.”

“One or two is OK, we will move over,” Goana says about shifting Sheppard's training routes, which also have to avoid cell towers and radio masts. “But now it’s almost completely clogged.”

Similar disputes between some military officials and wind farm developers are underway in North Carolina, Tennessee, and upstate New York. In California, the Navy wants to declare the Pacific Ocean from Big Sur to the Mexican border off limits to proposed offshore wind farms, because they would conflict with "the requirements of Navy and Marine Corps missions conducted in the air, on the surface, and below the surface of these waters."

Given that the White House is AWOL when it comes to promoting most sources of renewable energy, the big battles over wind energy's future are happening in statehouses across the country. It's a place where state officials who like the idea are pushing back against legislators allied with the fossil fuel industry. The battles over these wind farms aren't making headlines, but they are having an impact across the country. Every fight slows the transition to a renewable-powered world.

Advocates say that wind is a win-win: Property leases and wind farm jobs help struggling rural economies with a new source of revenue, while helping wean utilities off fossil fuels. But if the fight over military flight paths continues, wind companies will seek greener pastures elsewhere, and that won't help residents of eastern North Carolina, says Katharine Kollins, the Raleigh-based president of the Southeastern Wind Coalition, a nonprofit industry group covering 11 states.

"When you have legislators that are so bent on removing those options, wind energy companies that are investing millions of dollars in these sites are starting to pull back," Kollins said.

This debate isn’t new. Congress asked the Pentagon to deal with the problem back in 2011, and the Pentagon set up a Siting Clearinghouse to resolve these conflicts by reviewing technical and engineering studies and meeting with both wind developers and military base leaders. For offshore areas, the Pentagon also confers with the Department of Interior’s Bureau of Offshore Energy Management. So California may still get its offshore wind installations.

Last year, the Clearinghouse reviewed 795 wind farm proposals, a jump of nearly 30 percent in the past five years, according to Defense Department spokesperson Elissa Smith. The Pentagon hasn't rejected any proposals, but it has recommended developers to build fewer turbines, lower them, or move them somewhere else, Smith says.

Although Pentagon officials don't see wind power as an obstacle to military readiness, in the past two years, a growing number of state lawmakers are citing national security to block wind farms. That’s what’s happening along the North Carolina coastline, which is home to Marine Corps and Naval aviation facilities as well as a burgeoning wind industry.