US to open California coast to wind power
Wind turbines of the Block Island Wind Farm off the coast of Rhode Island in October 2016 (AFP)

The US government is set to open California's Pacific coast to offshore wind farms, officials announced Tuesday, adding to the approval of the nation's biggest wind project to date off Massachusetts.

The opening up of California waters came after a resolution to longstanding opposition from the Pentagon, which uses the ocean waters for military exercises and had put swaths of coast off limits to the industry, officials said.

This now gives the green light to the "first commercial scale offshore clean energy projects" on the West Coast, the White House said in a statement.

Two areas have already been identified off the central part of California near Morro Bay and the northern coast off Humboldt County.

"These identified areas will enable the build out of a significant new domestic clean energy resource for years to come," the White House said.

Between them, officials said, the two areas could support enough clean energy production to power about 1.6 million homes.

National climate adviser Gina McCarthy told reporters the Biden government was "thinking big and thinking bold" in its bid to leapfrog the nascent offshore wind turbine industry to a new level.

Earlier this month, Washington granted final approval for its biggest wind power project yet, which will be located off the coast of the north-eastern state of Massachusetts.

The "Vineyard Wind" project calls for up to 84 wind turbines to be built 12 nautical miles off Martha's Vineyard and Nantucket, two upscale islands off the Massachusetts coast.

Biden has set a goal of generating 30 gigawatts of energy from offshore wind by 2030.

The 800-megawatt Vineyard Wind project would provide enough power for 400,000 homes and businesses, the Interior Department said.

Currently the only ocean wind farms are small installations off the coasts of Virginia and Rhode Island.

Vineyard Wind, a joint venture between Avangrid Renewables and Copenhagen Infrastructure Partners, said the Atlantic project will be operational in 2023.