Floating platform for ocean-based wind turbines

Wind turbines may be one of the best renewable energy solutions, but as turbines get larger they also get noisier, become more of an eyesore, and require increasingly larger expanses of land.

One solution is ocean-based wind turbines, and while these have already been erected, they have traditionally been situated in shallow waters, where the tower extends directly into the seabed. That restricts the turbines to near-shore waters with depths no greater than 50m and precludes their use in deeper waters, where winds generally gust at higher speeds.

An alternative is placing turbines on floating platforms, said naval architect Dominique Roddier of Berkeley, California-based Marine Innovation & Technology.

He and his and colleagues have published a feasibility study of one platform design — dubbed WindFloat — in the latest issue of the Journal of Renewable and Sustainable Energy, which is published by the American Institute of Physics (AIP).

By testing a 1:65 scale model in a wave tank, the researchers showed that the three-legged floating platform, which is based on existing gas and oil offshore platform designs, is stable enough to support a 5MW wind turbine, the largest turbine that currently exists.

These mammoth turbines are 70m tall and have rotors the size of a football field.

The next step, Roddier said, is to build a prototype to understand the lifecycle cost of such projects. A prototype of the platform, which is being built in collaboration with electricity operator Energias de Portugal, should be in the water by the end of summer 2012.

The article, ’WindFloat: a Floating Foundation for Offshore Wind Turbines’ by Dominique Roddier will appear in the Journal of Renewable and Sustainable Energy. See: http://jrse.aip.org