The two top lawmakers on the Senate Energy Committee had threatened to oppose final passage of the funding bill in that chamber unless roadblocks to the 400 megawatt wind project were removed.

The compromise gives the Coast Guard more authority to weigh whether the windmills are a danger to passing ships, but "it prevents local special interests from torpedoing a reasonable and much-needed energy project in federal waters," committee chairman Pete Domenici said in a statement.

The White House had also weighed in and supported the project.

A House-Senate bargaining committee in April included a provision in the Coast Guard funding bill that would have allowed Romney to block a plan by Cape Wind Associates LLC to put 130 giant wind turbines near the tony resort islands of Martha's Vineyard and Nantucket.

Romney, a Republican, is an outspoken opponent of the project, as is US Sen. Ted Kennedy, a Democrat, and many wealthy residents who own coastal property and belong to exclusive yacht clubs in the area.

Kennedy, who was involved in crafting the compromise, said the project previously had "been moving forward irresponsibly before any safety rules for such large off-shore developments have been established."

On a clear day, the windmills would be visible from many of the area's resort homes, including the Kennedy family compound in Hyannisport six miles away.

Studies show the area has some of the strongest, most consistent wind in the eastern United States. At peak output, the project would generate more than 400 megawatts of electricity, enough to meet the needs of some 400,000 homes on Cape Cod and the nearby islands.