With alternative energy becomimg more and more important, the French have come up with a novel idea to further reduce costs of ocean deployment – Deskarati
Wind turbines attached to floating buoys can harness stronger, more sustained winds in the open ocean. But the floats now used for such deep-water installations may prove prohibitively expensive because the buoys needed to keep them above water are enormous. Now a project in France is turning the turbine design on its head for what developers hope will be a low-cost alternative.
French oil and gas engineering company Technip and wind-power startup Nenuphar recently announced Vertiwind, a two-megawatt wind turbine that they plan to float in Mediterranean waters by the end of 2013. The project employs a turbine with a main rotor shaft that is set vertically, like a spinning top, rather than horizontally, as in a conventional wind turbine.
The benefit of the vertical-axis design is that it lowers the turbine’s center of gravity. Vertiwind’s design stands 100 meters tall, but places the generator, which weighs 50 tons, inside a sealed tube beneath the turbine’s rotating blades, 20 meters above the sea. This makes the turbine less top-heavy, allowing for a significantly smaller flotation system, which would extend only nine meters below the surface of the ocean.
In contrast, a horizontal-axis turbine with the same power output and blades also reaching 100 meters high would need its generator to be 60 meters above the sea. A buoy built by Technip for a 2.3 megawatt horizontal-axis floating turbine prototype, owned by the Norwegian energy company Statoil, extends 100 meters below the surface.