After nearly a decade of review, the Dept. of the Interior gave the go-ahead on April 28 for the nation’s first offshore wind farm—the $1 billion Cape Wind project, located off the coast of Nantucket. Construction on the project could begin as early as this year, says the project’s developer.

But the project is highly controversial, and a broad coalition of historic-preservation and environmental groups, along with Indian tribes, say they will file a lawsuit to attempt to block the project.

In response to critics, the Interior Dept. says it will require Cape Wind Associates LLC, the Boston-based developer of the project, to modify its proposal to minimize potential adverse environmental and aesthetic impacts of construction and operation of the facility.

The project, which will be built about five miles off the coast of Massachusetts, would occupy a 25-sq-mile section of the Nantucket Sound and generate a maximum electric output of 468 megawatts, with an average anticipated output of 182 Mw. The project includes a 66.5-mile buried-submarine transmission cable system, an electric service platform and two 115-kilovolt lines connecting to the mainland power grid.

The Interior Dept. says the project would create several hundred construction jobs and be one of the largest greenhouse-gas-reduction initiatives in the nation, annually cutting carbon-dioxide emissions from conventional powerplants by 700,000 tons.

Modifications to Cape Wind’s original plan include a reduction in turbines from 170 to 130 as well as a reconfiguration of the turbine array to diminish any negative visual impact from the shoreline.

Industry observers say the decision on Cape Wind should be a boon to the offshore-wind-energy industry. The American Wind Energy Association (AWEA) says approximately 12 additional offshore wind projects are in various stages of development. “This project sends the message that the U.S. is open for business,” says Tom Vinson, AWEA’s director of federal and legislative affairs.

Interior Secretary Ken Salazar says the northeastern U. S. has the potential to tap one million Mw of offshore-Atlantic wind energy. “This will be the first of many projects up and down the Atlantic Coast [that] I expect will come online in the years ahead,” he says.

Among the groups that legally will challenge the decision are the Alliance to Protect the Nantucket Sound and the Animal Welfare Institute.

Some environmental groups have been supportive of the Cape Wind project, although some, like Environment America, have said the approval process could be improved.