BOSTON — The Obama administration has approved what would be the nation's first offshore wind farm, off Cape Cod, two government officials briefed on the decision confirmed today, inching the U.S. closer to harvesting an untapped domestic energy source — the steady breezes blowing along its vast coasts.

The officials spoke on condition of anonymity to The Associated Press because they were not authorized to speak publicly ahead of U.S. Interior Secretary Ken Salazar's announcement scheduled for this afternoon in Boston.

Salazar's decision on the controversial Cape Wind project clears the way for a 130-turbine wind farm in Nantucket Sound.

Cape Wind was in its ninth year of federal review, and Salazar stepped in early this year to bring what he called much-needed resolution to the bitterly contested proposal.

Approval of the project would break new ground in the drive toward renewable power, Massachusetts Environmental Affairs Secretary Ian Bowles said.

Cape Wind says it can generate power by 2012 and aims to eventually supply three-quarters of the power on Cape Cod, which has about 225,000 residents.