Investigation of wind shear coefficients and their effect on electrical energy generation

► Wind measurements are generally performed below wind turbine hub heights owing to the higher measurement and tower costs. ► Wind speeds are extrapolated to the hub height of wind turbine assuming constant wind shear. ► Some critical errors might occur between estimated and actual energy output of wind turbine. ► It is vital for energy investors to accurately predict the mean wind speed at turbine hub height due to economic reasons. Wind measurements are generally performed below wind turbine hub heights due to higher measurement and tower costs. In order to obtain the wind speed at the hub height of the turbine, the measurements are extrapolated, assuming that the wind shear is constant. This assumption may result in some critical errors between the estimated and actual energy outputs. In this paper wind data collected in Balıkesir from October 2008 to September 2009, has been used to show the effects of wind shear coefficient on energy production. Results of the study showed that, the difference between wind energy production using extrapolated wind data and energy production using measured wind data at hub height may be up to 49.6%.