A new approach to vertical extrapolation of wind speed and the effect of Hellmann constant on the wind energy potential analysis

Wind speed is one of the most important factors in the wind energy potential analyses. The accurate prediction of wind speed is possible through the application of the analysis method in which the appropriate existing data and the site specific variables are taken into acocunt. In this thesis, four-year wind data which have been acquired from a wind measurement mast in Çanakkale region near Aegean Sea have been analyzed. The measurements have been used in the vertical extrapolation method for calculating the wind speed at the wind turbine's hub height so that the wind energy potential analysis could be performed, and the turbine hub height wind speeds have been calculated using the power law. The Hellman constants used to measure the wind speeds have been found by the application of three different methods, one of which is the new approach offered in this study and other two are through traditional methods, and then the findings of these three different methods have been compared. It has been hypothesized that that in this new approach, the Hellman constants which can be found by considering the site specific factors would give more accurate results than the ones which are obtained by solely considering the average wind speed or the tables. After this comparison, it has been found out that the seasons and the times of sunrise and sunset affect the Hellman constant value the most and these variables have been taken into consideration in the analyses. Overall findings have indicated that the wind speeds measured via the new approach are 0,4 % higher than the ones found via the traditional methods, and also for the analysed site, wind energy potential is 0,8 % higher for the one analysed by traditional methods.