Wind power calculator

Calculate the power that a wind turbine can harvest :

The power calculated below is the mechanical input from the turbine to it's generator. How much of this potential power that's converted to useful electrical energy is another matter entirely; it will depend on mechanical & electrical losses in the generator and the type of charge control used if connected into a battery. These losses can be calculated, but will vary from system to system. As a rule of thumb, assume 60% is available:

Wind speed:            m/sec

COP (see note):       max 0.59 (theoretical limit)

Density of air:           kg/m³ - 1.225 is the density of dry air at 15ºC. Calculator here for other temperatures or humidities.

Diameter of blades:  m

Note: COP - coefficient of performance. This is the fraction of the energy in the wind that a particular turbine is able to harvest. There is a theoretical upper limit of 0.593; any real turbine will be less than this, determined by the particular turbine's design. A value of 0.35 would be typical. You can find the COP for your turbine by looking up the rated power output & wind speed from your turbine's published data. Enter the windspeed into this calculator, along with the blade's swept diameter and adjust the COP value until this calculator gives you the same power output as the turbine's rating. I'll be adding a calculator to find COP from a turbine's specification at a future date.