The Obama administration will offer leases next year for wind-energy development off the coasts of Massachusetts, Rhode Island and Virginia, the Interior Department said.

The agency, which oversees energy development in federal waters more than 3 miles from shore, set aside 277,550 acres divided into two wind-energy areas on the outer continental shelf, according to a statement today. The two areas are estimated to support more than 4,000 megawatts of wind power, enough for 1.4 million homes, Interior said.

The auctions will be the first competitive sales for wind energy on the outer continental shelf, where no projects are yet operating, according to the agency. The sales differ from leases previously awarded to Cape Wind Associates LLC and NRG Energy Inc. (NRG) for projects in Massachusetts and Delaware because those areas were deemed non-competitive by Interior, enabling a single developer to negotiate the leases in each case.