Evaluating offshore wind resources in India using ERA5 reanalysis: a statistical approach

This study assesses the suitability of ERA5 reanalysis data for offshore wind resource assessment along the coasts of Gujarat and Tamil Nadu, India. Using metrics such as mean bias error (MBE), mean absolute error (MAE), root mean square error (RMSE), and R-squared (R²), ERA5 wind speed and direction estimates were validated against observational data from lidar and meteorological mast measurements. Results demonstrate strong agreement, with correlation coefficients (R) of 0.949 and 0.958 for Gujarat and Tamil Nadu, respectively, and MBE values of -0.6 m/s and -0.55 m/s. Further analysis examined wind power density and Weibull distribution parameters across different offshore zones, highlighting substantial differences in wind characteristics between the two regions. Tamil Nadu’s Zone E recorded the highest wind power density at 609 W/m², along with a mean wind speed of 9.101 m/s and International Electrotechnical Commission (IEC) Wind Class I, indicating its suitability for high-capacity wind turbines. Conversely, Gujarat’s zones generally presented lower wind power densities, with values around 263-302 W/m², classifying most as IEC Wind Class III areas. Despite ERA5’s reliability, limitations exist in capturing complex offshore wind conditions influenced by dynamic atmospheric factors. Future research may incorporate advanced statistical models for more detailed wind characterization, aiding in optimized turbine placement and supporting India’s renewable energy targets.