The Trump administration suspended leases on Monday for five large offshore wind projects that are under construction off the US East Coast over what it called national security concerns, sending shares of offshore wind companies plunging.
The suspension was the latest blow for offshore wind developers that have faced repeated disruptions to their multi-billion-dollar projects under US President Donald Trump, who has said he finds wind turbines ugly, costly and inefficient.
The US Department of the Interior said the move was the result of complaints by the Pentagon that the movement of huge turbine blades for offshore wind projects, as well as the highly reflective towers that hold them up, cause radar interference that can make it hard to identify and locate threats.
The pause will give relevant federal agencies, "time to work with leaseholders and state partners to assess the possibility of mitigating the national security risks posed by these projects," the department said in a press release.
"The prime duty of the United States government is to protect the American people," Secretary of the Interior Doug Burgum said in the release.
The pause will affect Orsted's Revolution Wind and Sunrise Wind projects, Avangrid and Copenhagen Infrastructure Partners' Vineyard Wind 1 project, Dominion Energy's Coastal Virginia Offshore Wind, and Equinor's Empire Wind 1 project, according to the release.
New York Governor Kathy Hochul and Connecticut Attorney General William Tong said in separate statements on Monday that states affected by the freeze were reviewing their options.
The National Ocean Industries Association (NOIA), a trade group representing offshore wind developers, also urged the administration to end the pause quickly, pointing out that the Pentagon had been involved in approving the projects under past administrations.
"The regulatory process involves a rigorous framework for assessing the national security implications of proposed projects, and every project under construction has already undergone review by the Department of Defense with no objections," NOIA President Erik Milito said.
Shares in Danish energy firm Orsted, which owns two of the affected projects, traded down more than 12 per cent by late morning, with other companies such as Dominion and Equinor also trading lower.
Dominion said the suspension will threaten grid reliability for its Virginia customers, including military bases and data centres powering artificial intelligence.
"These electrons will power the datacenters that will win the AI race, support our war fighters, and build the nuclear warships needed to maintain our maritime supremacy," the company said in a press release.
Critics note, however, that such projects are largely underwritten by state subsidies, meaning private firms stand to benefit from public funding while taxpayers absorb much of the financial risk.
Orsted, Equinor, and Copenhagen Infrastructure Partners were not immediately available for comment.
In August, the administration had ordered Orsted to halt already advanced construction on the Revolution Wind project off Rhode Island, though a federal judge later lifted the ban.
Earlier in the year, the administration lifted a stop-work order on Equinor's Empire Wind in a compromise with New York state that paved the way for a natural gas pipeline Trump supports.
Trump campaigned for the White House on a promise to end the offshore wind industry - saying "windmills" are too expensive and hurt whales and birds - while promoting oil and gas.
The uncertainty has taken a financial toll on developers. Orsted raised $9.4 billion earlier this year to help fund US projects after potential partners were deterred by Trump's hostility to wind power.
Interior Secretary Burgum has previously said the administration is concerned that offshore wind installations can make the United States more vulnerable to attacks by swarms of drones.
(Reporting by Ryan Patrick Jones in Toronto and Stine Jacobsen in Copenhagen Writing by Richard Valdmanis Editing by Doina Chiacu, Toby Chopra, Frances Kerry, Rod Nickel)