Wind Turbine Power Calculator

Wind Turbine Power is evaluated from Rotor Diameter, Average Annual Wind Speed and Capacity Factor. The calculation reports Swept Area, Estimated Rated Power and Annual Energy Output.

Results

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About the Wind Turbine Power Calculator

Wind Turbine Power is treated here as a quantitative relation between Rotor Diameter, Average Annual Wind Speed and Capacity Factor and Swept Area, Estimated Rated Power, Annual Energy Output and Homes That Could Be Powered.

The calculator uses a multi formula configuration. Each reported value is read as a direct evaluation of the stored rules with the declared field formats and units.

Formula basis:
P = 0.5 x 1.225 x swept area (m^2) x wind speed^3 (m/s) x 0.40 efficiency
Annual kWh = rated kW x 8,760 hours x capacity factor
Diameter in feet converted to meters; mph converted to m/s

Interpret the outputs in the order shown by the result fields. Optional inputs affect only the outputs that depend on those variables.

Formula & How It Works

The calculation applies the following relations exactly as recorded in the metadata:

P = 0.5 x 1.225 x swept area (m^2) x wind speed^3 (m/s) x 0.40 efficiency
Annual kWh = rated kW x 8,760 hours x capacity factor
Diameter in feet converted to meters; mph converted to m/s

Each output field is produced by substituting the supplied inputs into the relevant relation and then applying the declared rounding or text format.

Worked Examples

Example 1: 20-ft diameter turbine at 12 mph wind (average US rural site)

Inputs

rotor_diameter: 20 wind_speed: 12 capacity_factor: 0.30
Swept Area: 314 sq ft. Estimated Rated Power: 1.1 kW. Annual Energy Output: 2,901 kWh/yr. Homes That Could Be Powered: 0.3 homes

With Rotor Diameter = 20, Average Annual Wind Speed = 12 and Capacity Factor = 0.3 as the stated inputs, the result is Swept Area = 314 sq ft, Estimated Rated Power = 1.1 kW and Annual Energy Output = 2,901 kWh/yr. Each value corresponds to the declared output fields.

Example 2: 100-ft diameter utility turbine at 15 mph wind (good commercial site)

Inputs

rotor_diameter: 100 wind_speed: 15 capacity_factor: 0.40
Swept Area: 7,854 sq ft. Estimated Rated Power: 53.9 kW. Annual Energy Output: 188,870 kWh/yr. Homes That Could Be Powered: 17.8 homes

With Rotor Diameter = 100, Average Annual Wind Speed = 15 and Capacity Factor = 0.4 as the stated inputs, the result is Swept Area = 7,854 sq ft, Estimated Rated Power = 53.9 kW and Annual Energy Output = 188,870 kWh/yr. Each value corresponds to the declared output fields.

Example 3: Backyard 10-ft turbine at 10 mph (marginal site)

Inputs

rotor_diameter: 10 wind_speed: 10 capacity_factor: 0.20
Swept Area: 79 sq ft. Estimated Rated Power: 0.16 kW. Annual Energy Output: 280 kWh/yr. Homes That Could Be Powered: 0 homes

With Rotor Diameter = 10, Average Annual Wind Speed = 10 and Capacity Factor = 0.2 as the stated inputs, the result is Swept Area = 79 sq ft, Estimated Rated Power = 0.16 kW and Annual Energy Output = 280 kWh/yr. Each value corresponds to the declared output fields.

Example 4: Offshore wind equivalent: 200-ft rotor at 20 mph (excellent offshore site)

Inputs

rotor_diameter: 200 wind_speed: 20 capacity_factor: 0.45
Swept Area: 31,416 sq ft. Estimated Rated Power: 511.06 kW. Annual Energy Output: 2,014,613 kWh/yr. Homes That Could Be Powered: 189.5 homes

With Rotor Diameter = 200, Average Annual Wind Speed = 20 and Capacity Factor = 0.45 as the stated inputs, the result is Swept Area = 31,416 sq ft, Estimated Rated Power = 511.06 kW and Annual Energy Output = 2,014,613 kWh/yr. Each value corresponds to the declared output fields.

Common Use Cases

  • Calculate wind turbine power output from wind speed
  • Estimate annual wind energy production
  • Compare wind turbine sizes for small wind projects