The Pentagon has halted the return of new onshore wind energy project reviews to the Federal Aviation Administration in recent weeks, leaving more than 250 wind farm proposals on private land without completed national security clearances, according to the American Clean Power industry association. The pending projects span over 30 states and represent at least 30 gigawatts of potential generating capacity, the association said.

The Pentagon evaluates wind energy projects during the FAA review process. Before a wind farm is built, the FAA conducts a regulatory review to determine whether turbines over 200 feet pose hazards to air navigation, and works with defense officials to assess whether the structures could create national security risks or interfere with radar. Wind developers and defense officials frequently negotiate mitigation agreements to address those concerns.

According to American Clean Power, developers first noticed issues last summer, when previously signed mitigation agreements were not countersigned by the Pentagon. In February, the Pentagon stopped issuing new draft mitigation agreements even after negotiations had concluded, and in April it canceled meetings to work on those agreements. Last week, routine processing of projects that did not require mitigation measures also stopped. About 50 of the pending projects are in Texas.

"If the projects remain stalled, it would dramatically obstruct the industry at a time when the power is needed to meet skyrocketing demand and help lower utility bills," said Jason Grumet, CEO of American Clean Power. Grumet said there had never been a backlog of that size or a near-systemwide halt in transmittals back to the FAA.

The Pentagon's siting clearinghouse is actively evaluating land-based wind energy projects to ensure they do not impair national security or military operations, according to a Pentagon statement, which added that the evaluation involves interagency coordination in accordance with statutory and regulatory requirements. Robert Thompson, principal deputy assistant secretary for energy, installations and the environment at the Department of Defense, wrote on April 8 that further review of wind energy proposals would be conducted as soon as feasible, citing delays from the government shutdown in the fall. "The department intends to complete review of all companies' proposals efficiently without compromising the integrity of the review," Thompson wrote.

American Clean Power wrote to the Pentagon in March to express concerns over the scope and duration of the delays. Consultancy firm Baringa said its clients are experiencing delays on wind projects at various stages of approval and that no new agreements are being signed. Many of the projects must begin construction by July 4 to qualify for expiring clean energy tax credits but cannot start without Pentagon signatures, said Tom Harper, a partner at Baringa. Most of the pending projects are at late stages of development with considerable time and resources already invested, he said.