Wind Turbine Annual Energy Calculator
Estimate how many kilowatt-hours a wind turbine will generate in a full year given its rated capacity and expected capacity factor. Use this to size battery storage, forecast revenue, or compare turbine models.
About this calculator
Annual energy production (AEP) tells you the total electricity a turbine is expected to deliver over one year. The formula used here is AEP (kWh) = ratedCapacity × (capacityFactor / 100) × 8,760, where ratedCapacity is the turbine's nameplate power in kW, capacityFactor is the fraction of time it effectively runs at full power (expressed as a percentage), and 8,760 is the number of hours in a year. The capacity factor bundles together the effects of wind variability, turbine downtime, and wake losses into a single number. Typical capacity factors range from 25% for modest onshore sites to 50% for high-quality offshore locations. AEP is the starting point for all financial models: dividing the lifetime AEP by total project cost gives the levelized cost of energy (LCOE) in $/kWh.
How to use
Consider a 2,000 kW (2 MW) turbine at a site with a 35% capacity factor. Step 1 — Convert capacity factor: 35 / 100 = 0.35. Step 2 — Multiply: 2,000 kW × 0.35 × 8,760 hours = 6,132,000 kWh per year, or 6,132 MWh. Enter ratedCapacity = 2000, capacityFactor = 35 to confirm approximately 6,132,000 kWh. To put this in context, the average U.S. household uses about 10,500 kWh per year, so this single turbine could power roughly 584 homes.
Frequently asked questions
What capacity factor should I use to estimate annual energy production for a wind turbine?
Capacity factor depends heavily on your site's wind resource and the specific turbine model. As a starting point, 25–30% is typical for low-wind onshore sites in hilly or inland terrain, 30–40% is common for well-sited flat onshore locations, and 40–55% is achievable at offshore or high-wind coastal sites. Turbine manufacturers publish power curves that, combined with site wind data, allow more precise estimates. For preliminary feasibility studies, 30–35% is a commonly used conservative benchmark for onshore projects.
How does rated capacity differ from average power output of a wind turbine?
Rated capacity is the maximum power a turbine produces under its design wind conditions—typically around 12–14 m/s. Average power output is the mean power actually delivered over a long period, accounting for hours of low wind, calm periods, and downtime. Average power equals ratedCapacity × (capacityFactor / 100). A 2 MW turbine with a 35% capacity factor averages only 700 kW over the year. Understanding this distinction is essential when designing grid connections, storage systems, or power purchase agreements.
Why are there 8,760 hours used in annual energy calculations for wind turbines?
There are 24 hours in a day and 365 days in a standard year, giving 24 × 365 = 8,760 total hours. This figure represents the maximum possible operating time for any power plant in a non-leap year. Multiplying rated capacity by capacity factor by 8,760 converts an instantaneous power rating into a total energy volume for the year. In leap years the correct value is 8,784 hours, though the difference (0.27%) is usually negligible for planning purposes. Some analysts use 8,784 for long-term P50/P90 yield assessments to avoid any systematic underestimation.