To clarify the wind veer characteristics with height and their effect on the wind turbine power outputs, an investigation was carried out at the wind farms with complex and simple terrains. A 2 MW and a 1.5 MW wind turbine were tested, each having an 80 m tall met mast and a ground lidar to capture wind veering. Wind veer conditions were divided into four types based on wind direction changes with height. The power deviation coefficient (PDC) and the revenue differences for the four types were derived from the estimated electric productions. As a result, the wind veer angle across turbine rotors were more significant at the complex site than at the simple site. For the two sites, the PDC values ranged from − 3.90 to 4.21% depending on the four types, which led to a 20-year revenue variation of − 274,750–423,670 USD/MW.