Assessment of offshore wind power including effects of sea surface roughness using observed wind statistics

The paper addresses how the offshore wind power can be assessed based on observed wind statistics at an offshore location. Results are exemplified for a Pierson-Moskowitz wave amplitude spectrum together with mean wind speed statistics from 11 sites in the North Sea and the North Atlantic. The ambient turbulence level, for example relevant for design of the wind turbine blades, is also estimated by adopting a wind gust spectrum. The sea surface roughness is specified using a formula given in terms of significant wave height and spectral wave steepness. The present method should be useful for making initial assessments of available wind power and ambient turbulence level at offshore sites based on wind statistics.