A turbine at a commercial-scale offshore wind farm is producing power for the U.S. electric grid for the first time, a milestone many years in the making. (Dec. 6) (AP Video: Ted Shaffrey)

A turbine at a large offshore wind farm is producing power for the U.S. grid for the first time

A turbine at a commercial-scale offshore wind farm is producing power for the U.S. electric grid for the first time, a milestone many years in the making. (Dec. 6) (AP Video: Ted Shaffrey)