Small Wind ROI
Calculate payback for small wind turbine from AEP and installed cost. Free online wind energy calculator with instant, accurate results.
Built for Wind Energy1 documented formula2 real workflowsPrivate in your browser
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A quick decision brief for this specific tool
Inputs that matter
Installed Cost, Turbine Rating, Capacity Factor, Electricity Rate
Output to expect
Small Wind ROI
How it works
1 documented formula across 1 calculation mode
- Keep 4 bounded inputs within the limits shown beside the fields.
- Confirm that every value uses the unit and time basis shown before comparing scenarios.
- Change one input at a time to see which assumption materially changes the result.
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Reference & details
How it works
Updated July 2026
How it works
Updated July 2026Wind Power Equation
Theoretical power extracted from wind depends on air density, swept rotor area, wind speed cubed, and the turbine's power coefficient (Cp). Real turbines achieve Cp of 0.25–0.45.
Annual_kWh = 0.5 × ρ × A × V³ × Cp × 8760Swept Area
Rotor swept area determines how much kinetic energy the turbine captures. Doubling rotor diameter quadruples swept area and potential output.
A = π × (D/2)²Simple Payback
Divide net installed cost by annual energy value. Include tower cost, interconnection fees, and maintenance. Small wind typically requires 50 ft+ tower height for viable ROI.
Payback = Cost / (kWh × rate)Updated: July 2026
Example Scenarios
A 7 m diameter turbine on a 80 ft tower at 5.5 m/s average wind speed.
Rotor Diameter: 7 mAverage Wind Speed: 5.5 m/sCp: 0.35Installed Cost: $55,000
→ Annual output: ~12,000 kWh; at $0.14/kWh payback: ~33 years — marginal without incentives
A 5 kW turbine at 6.5 m/s on open agricultural land with $0.18/kWh rate.
Rotor Diameter: 5.5 mWind Speed: 6.5 m/sInstalled Cost: $35,000Rate: $0.18/kWh
→ Annual output: ~10,500 kWh; value: $1,890/yr; payback: ~18.5 years
Replacing $0.45/kWh diesel generation with a 3 kW turbine at a remote site.
Turbine: 3 kWAnnual Output: 4,500 kWhDiesel Equivalent: $0.45/kWhNet Cost: $25,000
→ Annual savings: $2,025; payback: ~12 years — viable off-grid economics
Common Mistakes to Avoid
Common Mistakes to Avoid
Using hub-height wind speed at ground level
Wind speed increases with height. A 5 m/s reading at 10 m may be 6.5 m/s at 80 ft hub height. Use wind shear exponent (typically 0.14–0.20) to extrapolate.
Ignoring turbulence and siting obstacles
Turbines need clear exposure for 300 ft upwind and 100 ft downwind. Trees, buildings, and ridgelines create turbulence that reduces output 20–40% below predictions.
Underestimating maintenance costs
Budget $500–1,500/year for inspections, lubrication, and component replacement. Gearbox and bearing failures on small turbines are common after year 7–10.
FAQ
Most small wind turbines need average annual wind speeds of at least 5 m/s (11 mph) at hub height. Class 3 (4.5–5.5 m/s) is marginal; Class 4+ (6+ m/s) makes payback reasonable with current equipment costs.
Raising hub height from 40 ft to 80 ft typically increases annual output 30–50% due to higher wind speeds and reduced ground turbulence. The tower cost increase is usually justified by energy gain.
Yes. Small wind systems under 100 kW qualify for the 30% residential or business energy credit through 2032, significantly improving payback on qualifying installations.
Solar is cheaper per kWh in most US locations ($2.50–3.50/W vs $5–8/W for wind). Small wind makes sense where wind resources exceed Class 3 and open land allows tall towers without zoning restrictions.
Most jurisdictions require building permits, electrical permits, and sometimes conditional use permits. Setback requirements (distance from property lines) often dictate maximum tower height.
About Small Wind ROI
Small wind turbines (1–100 kW) can offset rural or off-grid electricity costs when sited in Class 3+ wind resources. This calculator estimates annual energy production from rotor geometry and wind speed, then computes payback against installed cost and local electricity rates.