Wind resource extrapolating tools for modern multi-MW wind turbines: Comparison of the Deaves and Harris model vs. the power law

Only relying on surface information, the Deaves and Harris (DH) model was tested in predicting annual mean wind speed, Weibull distribution and energy yield at turbine hub heights of 40, 80 and 140 m. Based on 3-year (2011-2013) 10-min observations from the mast of Cabauw, the DH model was compared to the power law. The DH model was forced being applied for all stability conditions, although actually developed for the strongest neutral wind conditions (when about 75% overall wind energy may be extracted). The DH model was the finest at higher levels and its accuracy generally increased with height: at 80 m, biases of 2% (mean wind speed) and 6.06% (energy yield) were achieved, while at 140 m biases of 1% and 6.16% were obtained, respectively. Since affected by a high sensitivity to site's roughness length, an accurate assessment of this parameter proved to be main model's shortcoming. In any case, currently-achieved scores encourage further applications of the DH model, which should be deemed as a challenging wind energy research topic. Since valid over the entire boundary layer, it may be regarded as an ideal and certainly forward-looking tool for addressing modern multi-MW turbines whose hub heights steadily increase.