The Department of the Interior is proposing a large expansion of U.S. efforts to make energy from offshore winds, with a plan centered off the Massachusetts coast. Here, a 2010 photo shows a sunrise over Nantucket Sound.
The offshore wind farm in the North Sea near Borkum, Germany, is nearly complete. The Riffgat facility, seen here on June 23, includes 30 turbines, each with a generating capacity of 3.6 megawatts.
David Hecker/Getty Images
A maintenance worker looks out over an off-shore wind farm in Liverpool, England in 2008. Some people are concerned about the potential health effects of noise from wind turbines.
Christopher Furlong/Getty Images