ABSTRACT
Current projects for offshore wind power extraction typically involve propeller-type turbines with hub heights on the order of 100m above sea level and placed on foundations at a water depth of up to 50m. Going from the wind speeds near the ocean surface to the productivity of megawatt wind turbines involves two additional calculations. For use in estimating power production from wind turbines, it is customary to scale wind speeds to the turbine hub height by using the scaling law for a stable atmosphere, as the error is considered low due to insensitivity at both low and high wind speeds. Decisions to build wind turbine parks are often taken on basis of expected average annual production, and global map of such production potentials. To address wind turbine operational issues such as the need for power exchange between regions or storage, blended data offer 6-hourly calculations of both the expected power output and direction from which the turbine must accept winds.
