Evaluation of wind measurement methods for determination of realistic wind shear: A case study in Aksaray, Turkey

Abstract

Wind energy has become a large and important market in Turkey. Wind resource assessment and hub height extrapolation are the most analyses during wind power plant development. Wind shear is a critical parameter for wind speed analyses in wind energy power plant projects. The study covered measurement analyses of LIDAR (Light Detection and Ranging) and wind measurement mast system data that were compared as common in literature. Then wind shear formation and analysis factors were realistically evaluated with the multi-criteria method first in the literature using wind speed, wind direction, WSC, roughness, turbulence intensity (TI) and correlation factor. Under 100 m measurements were extrapolated to 101 m and upper 101 m. The predicted 245 pieces of the data set by using power law and log law and the measured data set were correlated with an anemometer and the LIDAR measurements to figure out an efficient prediction method. 20 pieces of wind shear coefficients (WSCs) were calculated using mast-mast, LIDAR-LIDAR, mast-LIDAR and LIDAR-mast wind speed measurement. Then, these WSCs were applied and tested for various measured wind speeds and the instantaneous wind speed was predicted with WSC values. Simultaneously, the log law method was repeated for different roughness values and the ideal roughness value was calculated for the site specifications. These predictions provided specific information about the height of wind shear and TI height supported by LIDAR and anemometers. In comparing data estimated by the power-law and log-law methods with measurements, good and acceptable results were obtained with more than a 0.999 correlation coefficient.