BOSTON — After nine years of regulatory review, the federal government gave the green light on Wednesday to the nation’s first offshore wind farm, a fiercely contested project off the coast of Cape Cod.
Opponents said they would continue to fight construction of the farm, known as Cape Wind, which would sprawl across 25 square miles of Nantucket Sound.
But the decision is expected to give a significant boost to the nascent offshore wind industry in the United States, which has lagged far behind Europe and China in harnessing the strong and steady power of ocean breezes to electrify homes and businesses.
“This will be the first of many projects up and down the Atlantic Coast,” Interior Secretary Ken Salazar said at a news conference here in the Massachusetts Statehouse with Gov. Deval Patrick, a Democrat and supporter of the venture, at his side.
In announcing the much-anticipated decision, Salazar hastened to add that he was requiring the developer, Cape Wind Associates, to take several steps to mitigate possibly adverse effects on the environment — including views from the Kennedy Compound National Historic Landmark, which overlooks Nantucket Sound. Those steps include adjusting the turbines’ color and configuration.
Opposition to the proposal from Sen. Edward M. Kennedy, who died in August, had been a major thorn in the Obama administration’s side in advancing the project.
The Cape Wind farm would lie about 5.2 miles from the nearest shore, on the mainland, and about 13.8 miles from Nantucket Island. The tip of the highest blade of each turbine would reach 440 feet above the water.
The long-running struggle over the project underscores how divisive even a “clean” energy project can be in the United States.
Friends and foes have squared off over the impact it would have on nature, local traditions, property values and electricity bills; on the profits to be pocketed by a private developer; and even the urgency of easing the nation’s dependence on fossil fuels, a priority of the Obama administration.
Opponents argued that Cape Wind would create an industrial eyesore in a pristine area; supporters countered that it was worth sacrificing aesthetics for the longer-term goal of producing clean, renewable energy.
Developers say that Cape Wind will provide 75 percent of the power for Cape Cod, Nantucket and Martha’s Vineyard — the equivalent of that produced by a medium-size coal-fired plant. It would also reduce carbon dioxide emissions by the equivalent of taking 175,000 cars off the road, officials said, and provide 1,000 construction jobs.
In a nod to the concerns of the Kennedys — and presumably other property owners in the area — Salazar said he had ordered Cape Wind to limit the number of turbines to 130 instead of the initial 170, to move the farm farther away from Nantucket and to reduce its breadth to make it less visible from the Nantucket Historic District.