Skip to main content

Wind Turbine Betz Limit & Aerodynamic Power Calculator

Albert Betz proved in 1919 that no wind turbine can capture more than 16/27 (59.26%) of the kinetic energy in wind.

Diameter of blade swept circular area.

Upstream free wind speed.

Ambient air density (1.225 kg/m³ at sea level).

Turbine aerodynamic efficiency (typically 0.40-0.48).

Calculated Result
3.66 MW

Aerodynamic Power Captured

Betz Theoretical Max Limit

4.93 MW

Unchecked Wind Stream Power

8.31 MW

Rotor Swept Area

7854.0 m²

Calculation Breakdown

  1. Wind PowerP_wind = 0.5 * rho * A * V³ = 0.5 * 1.225 * 7854 * 12³ = 8.31 MW
  2. Captured PowerP_rotor = Cp * P_wind = 0.44 * 8.31 MW = 3.66 MW

What Is the Wind Turbine Betz Limit & Aerodynamic Power Calculator?

The Betz limit establishes the upper physical limit on power extraction from an open fluid stream.

How Does the Wind Turbine Betz Limit & Aerodynamic Power Calculator Work?

To extract 100% of wind energy, air would have to come to a complete stop, blocking airflow behind the turbine.

Wind Turbine Betz Limit & Aerodynamic Power Calculator Formula & Variables

The core mathematical equation utilized by this calculator is expressed as:

P_{\text{wind}} = \frac{1}{2} \rho A V^3, \quad P_{\text{Betz}} = \frac{16}{27} P_{\text{wind}}, \quad P_{\text{rotor}} = C_p P_{\text{wind}}

Wind power cubic velocity scaling, Betz theoretical limit, and aerodynamic rotor power.

How to Use the Wind Turbine Betz Limit & Aerodynamic Power Calculator

  1. Input rotor diameter, upstream wind velocity, air density, and aerodynamic power coefficient Cp.

Step-by-Step Example Calculation

3 MW Commercial Wind Turbine

Input Values:

rotorDiameterMeters:100
windSpeedMPerS:12
airDensityKgPerM3:1.225
powerCoefficientCp:0.44
Worked Steps: Predicts 8.31 MW unconstrained wind stream power, 4.92 MW Betz ceiling, and 3.66 MW captured rotor power.

Understanding Your Result

Shows swept area in m², available wind power, Betz theoretical ceiling, and captured output power in MW.

Factors That Affect the Result

  • Power scales with the cube of wind speed (V^3) and square of rotor diameter (D^2).

When Should You Use This Calculator?

  • Wind farm site resource assessment, turbine selection, and power curve modeling.

Assumptions & Limitations

  • Actuator disk theory assuming 1D inviscid steady flow with no wake rotation.

Frequently Asked Questions

Calculation Accuracy & Reference Note

Derived by Albert Betz in 1919.

Explore more tools and calculators in Math Calculators