A 2 MW wind turbine with 90 m rotor diameter in 12 m/s wind. Swept area A = pi x 45^2 = 6362 m2. Available power = 0.5 x 1.225 x 6362 x 12^3 = 6.73 MW. At Cp = 0.35 the turbine extracts 2.36 MW, near its 2 MW rating. This is why windy sites matter: power rises with v-cubed.