Can turbines benefit from wind veer?

Wind direction variation with height (wind veer) frequently occurs in the atmospheric surface layer and can impose a substantial impact on utility-scale wind turbine operations. Using the 10-year dataset from Eolos wind energy station hosting a 2.5 MW turbine, we identify four scenarios of wind veer based on the trends of wind direction change in turbine upper and lower rotors: VV, (upper rotor: veering, lower rotor: veering), VB (upper rotor: veering, lower rotor: backing), BV (upper rotor: backing, lower rotor: veering), BB (upper rotor: backing, lower rotor: backing). These veer scenarios can yield different influences on the lift and drag acting on different rotor sections, leading to turbine power deficit and surplus depending on specific turbine type and veer scenarios. Based on this fundamental understanding, we develop an optimal wind turbine yaw control strategy to maximize turbine power generation under wind veer conditions. The strategy has been tested on individual utility-scale turbines and wind farms, demonstrating up to 3% power gain under large wind veer conditions.