Estimating a Small Wind Turbine's Annual Energy Output
An estimate of the annual energy output from a wind turbine (in kilowatt-hours per year) is the best way to determine whether it and the tower will produce enough electricity to meet your needs.
A wind turbine manufacturer can help you estimate the energy production you can expect. The manufacturer will use a calculation based on these factors:
- Particular wind turbine power curve
- Average annual wind speed at your site
- Height of the tower that you plan to use
- Frequency distribution of the wind—an estimate of the number of hours that the wind will blow at each speed during an average year.
The manufacturer should also adjust this calculation for the elevation of your site.
To get a preliminary estimate of the performance of a particular wind turbine, you can use the following formula:
AEO= 0.01328 D2 V3
Where:
- AEO = Annual energy output (kilowatt-hours [kWh]/year)
- D = Rotor diameter, feet
- V = Annual average wind speed, miles-per hour (mph), at your site
Note: the difference between power and energy is that power (kilowatts [kW]) is the rate at which electricity is consumed, while energy (kilowatt-hours [kWh]) is the quantity consumed.