Formula for Calculating the Wind Power Produced
The formula used to calculate the wind power produced by a wind turbine or windmill is the following:
P = c x d x (D^2) x (v^3)
P: Power produced (mechanical) (Watts [W])
d: density of wind (kilograms per cubic meter [kg/m^3])
D: turbine blade diameter (meter [m])
v: velocity of wind (meters per second [m/s^2])
The constant c depends on the system of units used and the specific variables in the equation. The formula implies that once the wind speed doubles, the wind power increases by a factor of eight! Furthermore, if the diameter of the blades is doubled, the power increases by a factor of four! The faster the wind and the bigger the blades, the more power input we can get.
In order for the formula to be more accurate, another variable should be added that is related to the design efficiency as mentioned above. This is the efficiency number of the wind turbine and it is provided by the manufacturer.