Wind Turbine Power Output Calculator

Wind power formula:

P = 0.5 × ρ × A × v³ × Cp

Where:

• P = power output (watts)
• ρ = air density (typically 1.225 kg/m³ at sea level)
• A = swept area of the blades (π × r²)
• v = wind speed (m/s)
• Cp = power coefficient (efficiency)

Key concepts:

• Power increases with the cube of wind speed. Doubling wind speed gives 8× more power.
• Larger blades sweep more area, capturing more energy.
• The Betz limit (0.593) is the theoretical maximum efficiency. Real turbines achieve 35–45%.

Typical turbine sizes:

• Small residential: 3–10 m diameter, 1–10 kW
• Medium commercial: 20–50 m diameter, 100–500 kW
• Large utility-scale: 80–160 m diameter, 2–8 MW

Wind speed classifications:

• Light breeze: 2–3 m/s (4–7 mph)
• Moderate wind: 5–8 m/s (11–18 mph)
• Strong wind: 10–15 m/s (22–34 mph)
• Minimum for most turbines: 3–4 m/s (7–9 mph) “cut-in speed”