America’s First Offshore Wind Farm Completed

August 23, 2016 by Jeff Shepard

Construction on the Block Island Wind Farm, was completed last week with the installation of the final turbine blade. Now, the five fully-assembled GE Haliade turbines are ready to be commissioned and tested. The five Haliade turbines are each 330 feet tall and will generate a combined total of 30MW of electricity.

GE obtained the Haliade turbine technology as part of its acquisition of Alstom’s power and grid business late last year. The Block Island wind farm brings together the Haliade turbines, whose blade tips tower 600 feet above the water, and GE’s innovative gearless permanent magnet generators that can each produce 6MW of power.

Each 330 feet (100 meters) tower holds the 400-ton power-generating nacelle, a machine as large as a school bus, and three blades that weigh 27 tons each. The generator is split into three separate electrical circuits so that even if two circuits go offline, the turbine can still produce 2MW of electricity on the remaining circuit. Low maintenance and redundancy are important, especially for offshore installations, where treacherous waters and high wind can delay a repair trip for days or weeks.

The project should be at full speed by the end of the year, generating 125,000MWh of electricity. That’s enough to meet 90 percent of Block Island’s power needs and even supply surplus electricity to the mainland via undersea cable.

The Block Island farm will be the first offshore wind farm in the U.S. But the potential for U.S. offshore wind energy is massive — over 4,000GW, which amounts to more than four times the nation’s annual electricity production, according to the U.S. Department of Energy.