Annual Wind Energy Yield Calculator
Estimates a wind turbine's annual energy output in kWh and the resulting revenue from electricity sales. Ideal for project feasibility studies and investment return calculations.
About this calculator
Annual energy yield combines a turbine's rated power with how often and how efficiently it actually runs. The formula is: Annual Revenue = ratedPower (kW) × 8,760 (hours/year) × capacityFactor × (availability / 100) × electricityPrice ($/kWh). Here, 8,760 is the number of hours in a year. The capacity factor (expressed as a decimal, e.g., 0.35 for 35%) accounts for the fact that the wind does not always blow at rated speed. Availability captures scheduled and unscheduled downtime, typically 95–98% for modern turbines. Multiplying by the electricity price converts energy output into annual revenue. Note that the formula returns revenue directly; annual energy production in kWh is simply ratedPower × 8,760 × capacityFactor × (availability / 100).
How to use
Take a 2,000 kW turbine with a capacity factor of 0.35, 97% availability, and an electricity price of $0.06/kWh. Annual energy = 2,000 × 8,760 × 0.35 × (97/100) = 2,000 × 8,760 × 0.35 × 0.97 = 5,942,520 kWh. Annual revenue = 5,942,520 × $0.06 = $356,551. This means the turbine earns roughly $357,000 per year at these assumptions, giving a useful starting point for payback period and IRR calculations.
Frequently asked questions
What capacity factor should I use for a wind energy yield calculation?
Capacity factor varies widely with location and turbine technology. Onshore sites with moderate wind resources typically see 25–35%, while high-wind inland or coastal sites can reach 40–45%. Offshore wind farms often achieve 40–55% thanks to stronger, steadier winds. The best source for your site is a long-term wind resource assessment using measured data or ERA5 reanalysis. Using a capacity factor that is too optimistic is one of the most common errors in wind project feasibility studies.
How does turbine availability affect annual wind energy production?
Availability is the fraction of time a turbine is operational and able to generate electricity. Modern onshore turbines typically achieve 97–98% availability under full-service contracts. Every percentage point of availability lost reduces annual output by the same percentage — a drop from 98% to 95% on a 2 MW turbine running at 35% capacity factor costs roughly 52,560 kWh per year. Remote sites, harsh climates, and older equipment can push availability below 90%, significantly eroding project economics.
Why does average wind speed matter if capacity factor is already accounted for?
Average wind speed is the underlying physical driver of capacity factor: sites with higher mean wind speeds produce more energy relative to rated power. When you already have a reliable capacity factor estimate from measured data, average wind speed is not needed in this formula. However, if only wind speed data is available, capacity factor can be estimated from a turbine's power curve and the Weibull distribution of wind speeds at the site. Average speed alone is insufficient — a site averaging 7 m/s with low variability will outperform one averaging 7 m/s with high gusts and long calm periods.