The formula for the electric power is P = π/2 * r² * v³ * ρ * η, one watt is calculated as 1 W = 1 kg * m² / s³. Example: an offshore wind turbine with a radius of 80 meters at a wind speed of 15 meters per second has a power of 16.3 megawatts, if air density and efficiency factor have the given values.