U.S. Interior Secretary Ken Salazar said his department will "hopefully" decide by the end of the year whether to approve plans for what may be the nation's first offshore wind farm along the coast of Massachusetts.

The Interior Department is working toward an "expeditious conclusion" of the approvals needed for Cape Wind in Nantucket Sound, Salazar said today. "We'll have a final decision to be made hopefully by the end of this year," he said, speaking to reporters after hosting a conference at the White House on renewable energy.

Energy Management Inc., the Massachusetts-based developer of Cape Wind, would construct 130 turbines capable of generating 420 megawatts of electricity. The project's cost is "in excess of a billion dollars," project spokesman Mark Rodgers said in a telephone interview today.

The project was opposed by the late Senator Edward Kennedy, a Massachusetts Democrat, and others who questioned its effect on the sound. Two American Indian tribes in Massachusetts asked the government to designate the sound as a "cultural property," which would block the project.

The turbines are to be built more than 5 miles from land. They would each be 440 feet (134 meters) above the surface of the water and would be visible from the Kennedy family compound at Hyannisport.

"We would like nothing more than for Secretary Salazar or perhaps even President Obama himself to be able to announce Cape Wind's approval at that climate change conference in Copenhagen in December," said Rodgers.

Approval from the U.S. by the end of the year means the project "could be completed and producing power by the end of Obama's first-term" in 2012, he said.

Aside from the department's permission, the project is seeking reinstatement of an approval that expired from the Federal Aviation Administration.