Convert wind speed into available wind power per square meter of swept area. Uses the kinetic energy equation to show power density at any wind speed.
The power available in wind is governed by the kinetic energy equation: P = 0.5 × ρ × A × v³. This calculates the total power in watts passing through a given area at a given wind speed. The result is the raw power available — a turbine can only capture a fraction of this (limited by the Betz Limit to ~59.3%).
Wind power density (W/m²) is a standardized way to measure wind resource quality. A power density of 200 W/m² at hub height is considered moderate; 400+ W/m² is excellent. This metric allows comparison across different turbine sizes since it's independent of rotor diameter.
This calculator takes wind speed and air density to produce the total power passing through any given area, and the power density per square meter. Use it to quickly assess the wind resource potential at your site.
This analytical approach supports both immediate cost reduction and long-term sustainability goals, helping organizations balance economic and environmental priorities in their energy management.
Understanding wind power density lets you assess whether a site has enough wind resource to justify a turbine investment, independent of turbine specifications. Regular monitoring of this value helps energy teams detect usage anomalies early and address equipment malfunctions or operational issues before they drive utility costs higher. Having accurate metrics readily available streamlines utility bill analysis, budget forecasting, and investment planning for energy efficiency projects and renewable energy installations.
Power Density (W/m²) = 0.5 × ρ × v³ Total Power (W) = 0.5 × ρ × A × v³
Result: 210 W/m², 2,101 W total
At 7 m/s with standard air density: Power density = 0.5 × 1.225 × 7³ = 0.5 × 1.225 × 343 = 210 W/m². For 10 m² swept area: 210 × 10 = 2,101 W total available. A turbine at 40% efficiency would capture about 840 W.
NREL's wind power classification system rates locations from Class 1 (poor) to Class 7 (superb) based on power density at 50m hub height. Class 3+ locations (300+ W/m² at 50m) are considered viable for utility-scale development. The US Great Plains, coastal areas, and mountain ridges generally have the best wind resources.
Wind power density varies significantly by season. In most of the US, winter and spring have the strongest winds. Summer is typically the weakest season. This seasonal pattern complements solar energy, which peaks in summer. A wind+solar hybrid system can provide more consistent year-round production.
To estimate annual production: multiply power density by swept area, then by power coefficient (Cp), system efficiency, and 8,760 hours. For example: 250 W/m² × 10 m² × 0.35 Cp × 0.90 efficiency × 8,760 hrs / 1,000 = 6,891 kWh/year.
Wind power density is the raw power available per square meter of area perpendicular to the wind flow, measured in W/m². It combines wind speed and air density into a single metric that represents wind resource quality at a site.
NREL classifies wind resources by class: Class 1 (<100 W/m²) is poor, Class 3 (300–400 W/m²) is fair for utility use, Class 5 (500–600 W/m²) is excellent, and Class 7 (800+ W/m²) is superb. For small wind, Class 2–3 (150–400 W/m²) can be viable.
The cubic relationship means small wind speed increases have large power impacts. Going from 5 to 6 m/s increases power by 73%. From 5 to 7 m/s: 175% increase. This is why site selection and tower height are the most critical decisions in wind energy.
The Betz Limit caps theoretical extraction at 59.3%. Real turbines capture 25–50% of available power (Cp of 0.25–0.50). The rest passes through or around the rotor. Multiply power density by Cp to estimate actual turbine output per m² of swept area.
Divide mph by 2.237 to get m/s. For example: 10 mph = 4.47 m/s, 15 mph = 6.71 m/s, 20 mph = 8.94 m/s. Many wind resource maps report in m/s already.
Yes, through air density. Cold air is denser (more power per m/s) and warm air is less dense. At 35°C, air density drops to ~1.15 kg/m³ (6% less power). At −10°C, it rises to ~1.34 kg/m³ (9.5% more power).