Firm Says Vertical Axis Design Reduces Costs of Floating Wind Turbines

A French company has introduced a new floating wind turbine with a vertical axis, an innovation its designers say makes it far more cost-efficient than conventional turbines in open ocean waters where wind currents can be strongest. Unlike typical floating turbines, which can be prohibitively expensive to operate because the horizontal shafts require enormous buoys to stay afloat, the so-called “Vertiwind” design by the engineering company Technip uses a main rotor shaft that is set vertically, similar to a spinning top. While the 50-ton generator of a typical 100-meter turbine might be located 60 meters above the ocean’s surface, the new design allows engineers to place the massive generator at a height of roughly 20 meters above the water level. And by lowering the center of gravity, it requires a significantly smaller flotation system at the base — one that extends just nine meters below the water, compared with 100 meters for some systems. The company hopes to deploy the two-megawatt turbines in the Mediterranean by the end of 2013.