A Discussion on Prediction of Wind Conditions and Power Generation with the Weibull Distribution

Abstract

Assessment of profitability from installed wind turbines is normally a key factor in addition to an accurate measurement of frequency distribution of wind speed in a certain period of time and prediction of power generation under the measured conditions. The frequency distribution of wind speed is evaluated, in general, using the Weibull distribution. In order to predict the frequency distribution from the average wind speed, a formula based on the Rayleigh distribution is often used in which the shape parameter equal to 2 is assumed. The shape parameter is also used by the Weibull distribution, however, its effect on calculation of wind conditions and wind power is not sufficiently clarified. This study reports on evaluation of wind conditions and wind power generated as affected by the change of the shape parameter in the Weibull distribution regarding two wind turbine generator systems, which have the same nominal rated power but different control methods. It further discusses the effect of the shape parameter of prototype wind turbines at a site with the measured wind conditions data.