Clean energy advocates breathed a sigh of relief late last month when the North Carolina legislature adjourned without extending a ban on new wind farms set to expire Jan. 1.

It’s unclear, though, whether a powerful lawmaker will yet seize on a new state study to try to cement the wind moratorium — in part because the analysis isn’t public, and just one civilian has been authorized to see its results.

Sen. Majority Leader Harry Brown, who last year pushed for the suite of maps showing how wind farms could interfere with military operations, said three days before the end of session that even he hadn’t viewed the research.

“I haven’t seen anything to do anything with,” Brown said.

Wind proponents contend the mapping was duplicative and unnecessary, but the law required it to be finished in time “to inform the development of policies” during the summer legislative session. The deadline prompted fears that Brown would use the maps to advance a permanent ban on wind farms; he tried a similar tactic two years ago.

As it happened, Brown didn’t press for any wind energy legislation during the short, six-week session. But he’ll have another chance to do so when the General Assembly reconvenes in November.

“I don’t want to sit back and say, ‘oh, great we made it through the legislative session,’” said Katherine Kollins, president of the nonprofit Southeastern Wind Coalition. “I think it’s going to be wait and see until December.”

‘Layers and layers of data’

North Carolina is home to only one wind farm, a 104-turbine project near Elizabeth City. The moratorium has delayed at least two other projects in northeastern North Carolina, where wind speeds are high and counties are eager for economic development.

For Brown, the economic engine that matters most is the military. His Onslow County district hosts one of the nation’s largest Marine bases. Six other military installations in the region generate tens of billions of dollars in activity each year.

A 2013 state law prevents any wind farm that would “result in a detriment to continued military presence in the state.” The Federal Aviation Administration also won’t allow any project over 200 feet without sign-off from the Department of Defense.

But Brown still worries 500-foot tall turbines could interfere with military radar or flight routes, and cause military officials to close, downsize, or relocate installations to other states. The solution, he says, is a statewide map to rule out wind energy in certain places.

“The map says it’s okay here, it’s not okay here,” Brown has said. “To me that’s the only way we’re ever going to be able to resolve this issue.”

Critics of this approach say the military already has similar maps, and the information contained in them is fluid.

“Routes can change. How we approach the training can change,” said John Castellaw, a retired lieutenant general who spent 12 years stationed in North Carolina with the Marine Corps. “Once you get something like that that seems to be black and white, sometimes it doesn’t work out that way. You need a little more flexibility.”

Encapsulating complex information about ground and air military operations in a single map is also difficult, said Chuck Hefren, the nonpartisan legislative staff person who was in charge of the state study.

“I think there was some sort of an expectation that you could look at the map, and some layman would be able to say you can’t put a windmill there,” said Hefren. “But it’s really hard to do that with all these layers of data.”

The Navy designated the information in the study as “For Official Use Only,” so far preventing its public release, Hefren said.

“According to the military,” he said, “I’m the only one allowed access to this information.”

Hefren said a legislator could give him coordinates for a potential wind farm that he could plug into the mapping tool, producing a list of potential conflicts with military operations. But wind developers are already required to obtain and consider this information from the military.

“Nobody’s seen the maps,” said Kollins. But, she stressed,“they’re likely not that important. They never were.”

‘Sustainable energy and national security can live together’

No wind project has ever been built over the objections of the military — in North Carolina or elsewhere — but Castellaw admits communications between the Pentagon and local military communities has not always been perfect. That’s partly why last year President Donald Trump signed revisions into federal law to ensure local base commanders give the okay to new wind farms.

The changes were a key talking point in meetings this summer between Castellaw, another retired military leader and lawmakers. Rep. John Szoka, a Cumberland County Republican, says it’s Sen. Brown who should take credit for the modifications.

“They tightened up the law to get local bases involved, and that wasn’t there before,” said Szoka, a wind energy champion in the House. “So that’s kind of a win for him.”

But neither Szoka nor wind advocates know whether Brown agrees. Castellaw, who spent three of his four tours at New River Marine Corps Air Station in Brown’s district, couldn’t get an appointment with the senator this summer.

“It was really disappointing that he didn’t have the opportunity to meet with us,” Castellaw said. “At some point I would really like to assure him that sustainable energy and our national security are important to each other and they can live together. We just have to work toward it.”

Asked if his meetings with other lawmakers made him hopeful the moratorium would expire on schedule, Castellaw hedged.

“The price of freedom is eternal vigilance,” he said with a small laugh. But, he continued, “the sense that I got was that things are pretty set right now.”