Alternative approach to wind turbine performance index assessment

This paper presents a method for estimating the fixed and variable speed turbine performance index. The approach is based on Weibull wind probability distribution function and manufacturer-provided power curve. It is further shown that the existing turbine performance index formulation is only valid in case of variable speed turbines. A general approach to calculating the turbine performance index is derived, suitable for both fixed and variable speed wind turbines. Instead of choosing a particular model for approximating the power curve, commonly used polynomial fitting is employed. It is suggested to determine the best site for a given off-the-shelf turbine rather than finding the best theoretical turbine for a given site.