So far, offshore wind development has stuck close to shore where the turbines could be anchored directly into the sea floor. This means that the 2,000-plus megawatts of ocean-based wind in Europe have all been installed in around 50 meters of water or less, and the long-awaited Cape Wind project in Nantucket Sound also will sit in shallow waters.
For the same reason that heading a bit offshore yields consistent and strong winds, though, heading even farther offshore often will improve those conditions even further. To take advantage of the wind blowing over deeper water, there is movement now to use floating wind turbines as a way of avoiding the need to anchor into a deep sea bed. According to one company, the biggest turbines currently available could feasibly work on such floating rigs.
Marine Innovation & Technology's WindFloat can theoretically support giant 5-MW turbines. The floating rig, made up essentially of three platforms with the turbine tower extending from one of them, is designed to withstand the rigors of a "100-year storm," according to a paper published in the Journal of Renewable and Sustainable Energy earlier this month (by company employees). And according to Principle Power, who has purchased the technology for WindFloat, several projects are in the works that could see turbines in the water by 2011 or 2012.
The floating wind idea could remove some of the issues that have plagued offshore wind's entry into the US market. Decade-long objections to Cape Wind generally came down to the visual disturbances residents of Cape Cod claimed the turbines would produce. The project, finally approved by the Department of the Interior in April, would eventually have 130 turbines at 3.6 MW each, collectively capable of producing about 75 percent of Cape Cod's electricity demand.
Those visual disturbances, though, wouldn't even come up at, say, a proposed project off the coast of Oregon: instead of the five miles from Cape Cod's shores that would produce a line of half-inch-tall turbines on the horizon, floating turbines based 10 miles away would be largely invisible.
According to the journal paper's authors, several design features do still need to be improved on the WindFloat to ensure smooth operation in the harshest of conditions. Other companies, though, are already steps ahead: Norwegian oil and gas giant Statoil recently completed construction of its first floating turbine several miles off the coast of Norway. Dubbed the Hywind, the company will spend the next two years testing the turbine before moving forward with further installations.
Image via Principle Power