WASHINGTON — Visitors to Rehoboth Beach, Del., soon may be greeted by more than sand dunes, gulls and beach umbrellas. If offshore wind advocates have their way, scores of 140-foot blades will be spinning in the ocean breeze nearly a dozen miles away, barely visible to the sunbathers.

Offshore wind has taken a back seat to offshore drilling for oil and natural gas in the current energy debate. But those wind-driven turbines probably will be operating long before oil platforms appear off Atlantic Coast states.

Delaware hopes to be the first state to construct a wind farm off its coast, although the idea also has drawn attention in Maine, Massachusetts and Rhode Island. The Delaware project is scheduled to be completed in 2012.

Proponents say wind offers more long-term energy independence than offshore oil. Residents along the Eastern Seaboard are embracing it as a stable-priced, environmentally friendly energy alternative.

“When people see the price of gas hit $4, they are very open to having discussions about alternatives,” said Stephen Smith, executive director of the Southern Alliance for Clean Energy, a nonprofit group.

Wind energy today accounts for only 1 percent of the nation’s electricity. A May report from the Energy Department concluded that wind energy could generate 20 percent by 2030, with offshore sources accounting for nearly 20 percent of that. Projects mostly would be located along the Atlantic coast because the seabed floor elsewhere drops off too quickly to anchor turbines.

Experts say the Gulf of Maine offers enormous potential for wind energy projects. However, the gulf’s deep waters and often brutal weather pose even more technological challenges than the comparatively shallow-water wind turbines proposed in Delaware and other locations.

Several groups, including researchers at the University of Maine and private companies, are working aggressively to develop floating platforms capable of supporting wind turbines deployed in deep coastal waters.

In Delaware, offshore wind has caught everyone’s imagination, said Patricia Gearity, a member of Citizens for Clean Power, a grass-roots organization based in the state.

“People liked that it was homegrown wind, that we weren’t going to import it from somewhere else,” said Jeremy Firestone, a professor of marine policy at the University of Delaware.

Offshore wind supporters say recent proposals have not faced the same kind of opposition that previously dogged projects off Massachusetts’ Cape Cod and New York’s Long Island. But even on Cape Cod, attitudes are changing. Where critics once held a floating anti-wind farm demonstration, polls show that public opinion has swung in favor of an offshore project.

The Long Island project was scrapped last year. But fishermen in neighboring New Jersey who once opposed offshore wind power have banded together to submit one of five bids for a 350-megawatt wind farm that would produce enough electricity for up to 100,000 households. Rhode Island may select a developer this fall for a wind energy project.

Delaware residents took to the blogosphere, called their legislators and turned out in droves at public hearings to push for the proposed project off Rehoboth Beach. It stalled last year, but months of negotiations and strong grass-roots organizing resulted in its approval by the Delaware Legislature in June.

“During that period of time, you saw headline after headline roll out about the increase in prices, not only in oil, not only in gas, but the big spike in natural gas and propane costs,” said Gearity, 58, a retired lawyer.

The project, proposed by Bluewater Wind, would include 60 to 200 wind turbines spaced about a half-mile apart. Delmarva Power has agreed to buy electricity from the project for 25 years. Bluewater is owned by the global investment firm Babcock & Brown, which operates wind farms in several states.

For each turbine, a pole would be hammered about 90 feet below the seabed floor. Another pole would rise above the water with three 140-foot spinning blades at the top. At the highest point, the turbines would reach up about 400 feet; by comparison, the Washington Monument is about 555 feet.

Unlike its mid-Atlantic neighbor, the Cape Cod project has faced vocal and well-funded opponents who complained it would mar the ocean vista. Rising energy prices have made that argument less persuasive, said Barbara Hill, executive director of Clean Power Now, an independent Hyannis, Mass.-based organization that favors the project.

The 130-turbine project has cleared most of the regulatory hurdles and proponents are hopeful it will be in operation within four years.

Cape Wind Associates, a subsidiary of the New England power company Energy Management Inc., has spent more than $30 million on the Massachusetts project, investing profits from its natural gas-fired power plants, said Cape Wind spokesman Mark Rodgers.

In New Jersey, Daniel Cohen, president of the offshore wind developer Fishermen’s Energy, said the organization reassessed its opposition, deciding to view offshore wind as an opportunity, not a threat.

“The public has a heightened interest to finding solutions in what it sees as a growing problem in our dependence on fossil fuels,” said Cohen, who owns Atlantic Capes Fisheries in Cape May, N.J. Fishing company owners have put up the money for the project’s development stage.

No formal offshore wind power proposal has surfaced in Maine, although officials from one company, Blue H USA, say they are exploring the possibility of deploying up to 90 turbines in the deep waters of the Gulf of Maine. The company also is moving forward with a windenergy demonstration off the coast of Massachusetts.

Maine already has New England’s largest land-based, utility-grade wind farm. But former Gov. Angus King has said the state should launch a major research and development project to create a $15 billion network of offshore wind turbines in the Gulf of Maine over the next decade.

King, who is working on two conventional wind farm proposals in western Maine, calls the Gulf of Maine “the Saudi Arabia of wind.”

Significant obstacles to offshore wind remain.

Policymakers and utility companies need to commit to long-term contracts, said Firestone, the University of Delaware professor. He pointed out that New Jersey and Rhode Island still do not have buyers for the power from the proposed projects.

There also needs to be more stability in the federal government’s support for wind power, said Laurie Jodziewicz, manager of siting policy at the American Wind Energy Association. When Congress allowed a renewable energy tax credit to expire in the past — in 2000, 2002 and 2004 — wind capacity installation dropped 93 percent, 73 percent and 77 percent, respectively, from the previous year. A current tax credit is set to expire Dec. 31.

Proponents point out that most of the technology hurdles have been cleared, though costs remain high. They look at the almost 1,100 megawatts of offshore wind farms in European waters and say the Cape Cod and projects could jump start offshore wind energy in the United States.

“This will be a game changer once this project is built,” said Hill, the Cape Wind advocate. “We are going to be dancing on Craigsville Beach someday, looking out and seeing the turbines spinning.”

BDN writer Kevin Miller contributed to this report.