Exploring likely limits of commercial capacity is more useful than forecasting specific maxima for given dates. Available wind turbine power is equal to half the density of the air (which is 1.23 kilograms per cubic meter) times the area swept by the blades (pi times the radius squared) times the cube of wind velocity. Assuming a wind velocity of 12 meters per second and an energy conversion coefficient of 0.4, then a 100-megawatt turbine would require rotors nearly 550 meters in diameter.
