Developers, state officials and federal agencies working toward the creation of a thriving wind industry off California's Central Coast have encountered a formidable opponent: the U.S. military.

The Pentagon's space restrictions in West Coast waters have so far stymied efforts to generate carbon-free electricity using floating wind turbines above the Outer Continental Shelf. The conflict threatens to further delay the federal government's auction of leases in the state's most desirable area for offshore wind energy development, originally planned for 2018.

Four years after reviewing the proposal for California's first major floating wind farm, offshore Morro Bay, the U.S. Department of the Interior's Bureau of Ocean Energy Management, or BOEM, is stalled in the planning stages of a competitive leasing process after the Department of Defense in 2019 objected to two of the three areas identified for possible development.

While the sites attracted interest from more than a dozen developers vying to build several gigawatts of offshore wind farms on floating platforms — a prerequisite for California's deep coastal waters — it is unclear how long it may take to launch large-scale facilities off the state's 840-mile coastline.

"There's still much work to be done to identify adequate space in the ocean so that a sustainable offshore wind industry can be established in California," Adam Stern, executive director of Offshore Wind California, a trade group recently founded by global offshore wind developers, said in an email.

Coastal defense vs. renewable energy

Among the group's members are some of Europe's largest players in conventional offshore and floating wind projects, including Norway's Equinor ASA and Denmark's Ørsted A/S, as well as California-based Principle Power Inc., a floating offshore wind technology company backed by Spanish oil giant Repsol SA and Norwegian industrial offshore company Aker Solutions ASA.

The group is urging California to set an offshore wind power target of 10,000 MW by 2040 to help diversify the state's approach to completely decarbonizing its power sector by 2045. To do so, the group hopes to lean on "continued collaboration" to identify the best areas for offshore wind development, "while also recognizing the nation's coastal defense priorities," Stern said.

The Pentagon is open to "additional exploratory discussions," Steve Chung, director of the Defense Department's encroachment program, said during a March 9 meeting of a task force that California launched with BOEM to identify appropriate locations for offshore wind development.

But an initial attempt at compromise does not look promising.

The reduced areas potentially available for lease on the Central Coast, detailed in a revised map the California Energy Commission released in February, leave no room for full-scale commercial offshore wind projects, industry and BOEM officials acknowledged.

Responding to the Defense Department's objections, the new map shows only about around 80 square miles of non-contiguous ocean surface across two locations, said Molly Croll, offshore wind program director for the American Wind Energy Association's California chapter, at the March meeting. That compares with roughly 600 square miles across two previously identified Central Coast sites and is "not sufficient sea space to stimulate the development ... of our emerging industry," Croll said.

Offshore wind developers want to take advantage of transmission capacity on the Central Coast freed up by the 2014 retirement of the nearly 1,000-MW natural gas-fired Morro Bay project and by Pacific Gas and Electric Co.'s scheduled 2025 retirement of the 2,240-MW Diablo Canyon nuclear power plant, the state's largest generating station and a major source of zero-carbon power. An area adjacent to Diablo Canyon previously considered for wind development has been taken off the table, at least for now.

'Not quite there yet'

While the two new sites under consideration near Morro Bay could hold only one small project, new wind facilities along the Central Coast need to support multiple projects sized 1,000 MW or larger to fill the existing transmission capacity and maximize project economics, Croll said.

BOEM is seeking, so far without success, an area on the Central Coast that could host 3,000 MW to 5,000 MW, Doug Boren, BOEM's regional supervisor, said during the meeting.

"It's safe to say that we're not quite there yet," he said.

Croll asked for commercial leasing to start "as quickly as possible" for federal waters off of Morro Bay and on the coast of Humboldt County, in northern California.

The rugged Humboldt shore, while free of the military opposition developers have encountered on the Central Coast, is constrained by a lack of transmission. But for a state seeking to decarbonize its electricity supply by midcentury, that is a shortcoming California may need to address, according to one state official.

"On the North Coast the wind resource is very strong ... and the DOD conflicts are less, so as we look longer term at significantly larger potential amounts of offshore wind, we do have to look at the transmission question," said Karen Douglas, a member of the California Energy Commission.