WASHINGTON Five companies are interested in developing wind farms in the ocean off North Carolina, hoping to take advantage of what could be the East Coast’s most promising chance to create energy through giant turbines anchored to the sea floor.

The idea is embraced by both Republican Gov. Pat McCrory and the Sierra Club, who see North Carolina as the next potential center for renewable energy in America. But big obstacles remain before the whirling farms become a reality. Offshore wind is an expensive form of energy, and Congress is losing interest in federal subsidies to encourage it. There are no offshore wind farms in the United States, although they’re common in Europe.

The federal government asked companies in December whether they’d be interested in North Carolina offshore wind development. Five responded positively in filings released Tuesday. One is Virginia Electric and Power Co., part of the Dominion utility that serves Virginia and northeastern North Carolina.

“We responded we are interested, but there is a long way to go,” said Dominion spokesman Dan Genest. “We are interested. We would like to be a player. There’s a lot we have to learn, though.”

The federal government has to finish an environmental study before auctioning offshore leases. It also needs to decide whether to change areas considered for wind farms in light of newly released public comments. Those include the assertion of the World Shipping Council, a trade association that represents container vessels, that inviting wind farm proposals off Kitty Hawk is “dangerous and imprudent” for shipping.

Two potential development areas are between Myrtle Beach and Wilmington, while another is beyond the Outer Banks, across from the island towns of Kitty Hawk, Nags Head and Manteo. All potential areas are at least 6 miles from shore.

National Renewable Energy Laboratory estimates suggest that North Carolina’s offshore wind potential is the highest on the East Coast. The five companies interested in leasing did not make binding commitments or detailed proposals. But Brian O’Hara, president of the N.C. Offshore Wind Coalition, said their responses are still a good sign wind farms will be coming.

“I’m excited to see this level of interest,” he said. “This is great.”

O’Hara said it could be at least five years before the turbine construction would begin.

Duke Energy spokesman Thomas Williams said Tuesday the company doesn’t oppose offshore wind projects and would be interested in purchasing such energy if its price were comparable to that of other renewable energy sources.