WASHINGTON — Seattle’s Principle Power will receive up to $47 million in federal grants for its proposed floating wind farm off Coos Bay, Ore., pushing it closer to generating the nation’s first electricity from offshore West Coast winds.

The U.S. Department of Energy on Wednesday named Principle as one of three offshore wind projects chosen to receive the grants over four years. The other recipients, chosen from seven competitors, are the Fishermen’s Energy project off the coast of Atlantic City, N.J., and Dominion Virginia Power off Virginia Beach, Va.

Principle’s WindFloat project plans to use novel, triangular floating platforms to anchor turbines in the deep waters off the West Coast. The $200 million, 30-megawatt wind farm would place five turbines about 17 miles from shore.

Principle two years ago successfully tested a smaller prototype in Aguçadoura, Portugal.

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Energy Secretary Ernest Moniz said offshore winds hold vast sources of potential energy that could be tapped to create jobs and to diversify the nation’s energy portfolio. More than 60 percent of U.S. offshore winds — including along the entire length of the West Coast — are found over waters that are 200 feet or deeper. Such depths make it difficult to economically deploy traditional single-pile turbines driven into the ocean floor.

Kevin Banister, WindfFloat project manager, said the government grant would help the company’s plan to start generating electricity by 2017.

“This enables us to really move ahead,” he said.

In March, Principle signed a partnership with Deepwater Wind of Providence, R.I., to become the project developer in Coos Bay.

Principle’s shareholders include Energias de Portugal, Spain’s oil-and-gas giant Repsol and individual investors.

Gov. Jay Inslee, for whom developing renewable energy is a personal passion and a legislative priority, said Principle’s federal grants could help the Pacific Northwest take the lead on a pioneering technology.

This project “can represent a world-leading advancement in wind-energy-demonstrating technologies and methodologies that not only open huge new areas to the prospect of renewable-energy development but also bring jobs and opportunity,” Inslee said in a statement.

The nation’s first offshore wind farm was proposed in 2001 off Cape Cod, Mass. But to date, no U.S. offshore wind turbines are generating utility-scale electricity.

Kyung Song: 202-383-6108 or ksong@seattletimes.com. Twitter: @KyungMSong