A federal judge on Thursday ordered the Pentagon to lift its freeze on reviewing onshore wind projects and to end some of the delays that have brought U.S. wind power development to a standstill.
Judge Karin Immergut of the U.S. District Court for the District of Oregon issued a preliminary injunction in a lawsuit that a coalition of renewable energy groups filed against the Defense Department. The groups argued that the Trump administration has unlawfully delayed dozens of wind projects across the country by halting military reviews that were once considered routine.
In her ruling, Judge Immergut, who was appointed by President Trump, said that the renewable energy groups were likely to prevail on the merits and that the Pentagon had violated legal deadlines when it stopped its reviews. She ordered the agency to resume reviewing wind projects and to report back to the court on its progress every 30 days while the broader legal case played out.
The Defense Department did not immediately respond to a request for comment.
Since April, the Pentagon has halted all military reviews of proposed wind farms, which are meant to ensure that turbines don’t interfere with radar or flight paths. While the Trump administration has cited national security as a rationale, the coalition of renewable energy groups said the delays were an unjustified tactic to thwart wind power, a technology that Mr. Trump has derided for decades.
The delays have led to a “total halt of all wind development in the United States,” the groups argued. At least 106 planned wind projects in 21 states have been stalled indefinitely, representing an estimated $47 billion in potential investment.
Before any large wind farm can begin construction, its developers need to apply for clearances from the Federal Aviation Administration, which regulates the national airspace. As part of that process, the F.A.A. refers the application to the Pentagon, which checks to see whether a project might interfere with military radar or nearby air bases.
In the past, many wind projects have quickly received “no hazard” determinations, allowing them to move forward. But some projects do create issues, and they typically need to reach a mitigation agreement with the Pentagon. That might involve the company paying to upgrade nearby radar systems or modifying the layout of its turbines.
This process was for years considered routine and predictable, with deadlines set by Congress. But last August, wind developers began encountering severe delays. Companies that had negotiated mitigation agreements could not move forward because top Pentagon officials would not deliver the final signatures needed.
Then, in April, the review process halted entirely, and Pentagon staff were directed to stop work on wind projects, according to the lawsuit filed by renewable energy groups. Meetings with developers were suddenly canceled.
During oral arguments on Tuesday, lawyers for the Justice Department argued that the federal government was trying to assess potential national security risks from new wind projects, such as the possibility that the turbines could make it harder to detect drones, and that there were no political motives for halting wind.
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But lawyers for the renewable energy groups countered that developers had not received an adequate explanation for why many projects were stalled, and that even if some projects might pose concerns, a halt on all new wind turbines nationwide was too broad and affected projects that clearly were not a threat.
Wind power currently provides about 10 percent of the nation’s electricity. About 15 gigawatts worth of wind projects are currently under development and have already received F.A.A. approval. But an additional 29 gigawatts are awaiting review by the Pentagon, according to the lawsuit. (One gigawatt of wind can provide enough electricity for roughly 300,000 homes, although wind turbines don’t run at all hours.)
In their lawsuit, the coalition of renewable energy groups said that further delays could jeopardize many projects. Some may miss deadlines to qualify for federal tax credits, while others may get canceled entirely.
The new ruling does not necessarily compel the Pentagon to approve specific wind farms. But the court has ordered the agency to restart reviews for a wide range of projects and follow legal deadlines. If there are further delays, developers could press for relief for individual projects once the case is decided on the merits.
The delayed reviews are the latest in a series of extraordinary actions by the Trump administration to halt the expansion of wind power in the United States. On his first day in office, Mr. Trump issued a moratorium on all approvals for wind farms on federal land, and the Interior Department last year issued stop-work orders for five wind farms in the Atlantic Ocean that were already under construction. More recently, the administration has so far agreed to pay several companies $3.9 billion to abandon their offshore wind plans, including in one deal announced Thursday.
Mr. Trump has called wind turbines ugly and expensive, and has instead pushed to meet rising power demand with fossil fuels like coal and natural gas.
“My goal,” he said in January, “is to not let any windmill be built.”
Federal courts have ruled against many of those actions. This year, several judges said they were not convinced by the administration’s arguments that offshore wind farms posed a threat to national security and allowed the five projects currently under construction to proceed.