Company hopes to build 4MW floating wind farm off the coast of Massachusetts—the first of its kind in the world.

Boston-based Blue H USA has submitted a permit to the U.S. Army Corps of Engineers to test a structure that would be used for floating offshore wind turbines.

Blue H USA is applying to test a demonstration unit on the outer continental shelf approximately 23 miles off the Island of Martha's Vineyard and about 32 miles southeast of Block Island, Rhode Island.

If all goes well with the test platform, Blue H hopes to develop a 120-turbine, 420-megawatt wind farm in a 40 square mile area near the test site.

Currently, only two floating wind turbine projects exist in the world. StatoilHydro's HyWind project in Norway and a two-turbine pilot project operated by SeaEnergy Renewables, is located off the east coast of Scotland.

The plan

The location of the proposed test site is just 30 miles southwest of the proposed location of the embattled Cape Wind offshore project in Nantucket Sound. Cape Wind would be located in what is probably one of the best places on the East Coast to build the nation’s first offshore wind farm: in the near-shore, protected and shallow waters of Handkerchief Shoals. But that very proximity to land is what also has made it a very difficult place to build a wind farm — NIMBY opposition to Cape Wind has made the permitting process messy, expensive and long.

But floating turbines can be placed in much deeper waters, where the winds are stronger and more consistent—and the turbines can be virtually invisible from shore, alleviating some of the NIMBY pressure likely to bubble up from near-shore projects.

The technology

Blue H’s Submerged Deepwater Platform technology has been adapted from technology used on offshore drilling platforms and is now being applied to offshore wind power.

Each of Blue H's units consists of a buoyant steel body, which is held ‘semi-submerged’ under water by chains. The chains connect the buoyant body to a counterweight on the sea bottom, keeping the buoyant body constantly tensioned.

Unlike a conventional wind turbine that rests on a monopole or tripod driven into the sea floor, Blue H utilizes a submerged deepwater platform anchored to the sea floor with pilings driven into the seabed. Blue H's technology can be deployed in water depths from 30 to 300 meters and the proposed test will be conducted at a water depth of 51 meters (167 ft).

The unit will be constructed in a shipyard and will be towed to the proposed deployment site. On arrival at the site, the structure will be sunk into place.

This particular platform will be submerged 66 feet below mean sea level and anchored with a counterweight. A tower with monitoring equipment will be mounted on the platform and will stand approximately 197 feet above the ocean's surface.

The demonstration unit will remain in place for one year, gathering engineering and environmental data and transmitting it to a shore station via satellite using a combination of photovoltaic cells and battery packs.

The Martha's Vineyard Times