How this instrument works
A wind turbine's physical output — captured by the power formula relating air density, rotor size, wind speed, and power coefficient — is only half the story of whether it's worth operating. The other half is straightforward economics: multiply annual energy generated by the price it sells for to get revenue, then subtract whatever it costs to keep the turbine running over that same year.
Operating costs for a wind turbine cover more than most people expect from something with no fuel to buy: scheduled maintenance and gearbox servicing, insurance, land lease payments where applicable, and periodic major component replacement (blades, gearboxes, and generators all wear over a turbine's multi-decade life). None of that is free just because the wind itself is, and a turbine generating impressive amounts of energy can still run at a loss if its operating costs outpace what that energy sells for.
This is the same profit arithmetic that applies to any revenue-generating asset — revenue minus cost equals profit — just applied specifically to a wind turbine's annual energy output and the price it commands, whether that's a wholesale electricity price, a power purchase agreement rate, or the retail rate a small turbine owner offsets against their own electricity bill.
- Enter Annual energy generated (kWh) — from turbine specifications, a wind resource estimate, or actual metered production.
- Enter Sale price per kWh ($) — the price received per kilowatt-hour, whether wholesale, contracted, or a retail offset rate.
- Enter Annual operating cost ($) — maintenance, insurance, land lease and any other yearly costs of keeping the turbine running.
- Read Annual profit ($) — revenue minus operating cost; a negative figure means the turbine ran at a loss that year.
Worked example — 50,000 kWh/year at $0.12/kWh
A small wind turbine generates 50,000 kWh over a year, sells that energy at $0.12/kWh, and costs $3,000/year to operate. Revenue = 50,000 × 0.12 = $6,000; profit = $6,000 − $3,000 = $3,000.
That $3,000 annual profit is the turbine's net financial return for the year — a useful figure for comparing against the turbine's upfront installation cost to estimate a payback period, though this calculator itself computes only the single year's operating profit, not a multi-year return on the initial investment.
Questions
What typically counts as annual operating cost for a wind turbine?
Routine and scheduled maintenance (inspections, lubrication, component wear checks), insurance, any land lease payments if the turbine sits on leased ground, grid connection fees where applicable, and a reasonable annual allowance for eventual major component replacement like gearboxes or blades, which wear out over a multi-decade turbine lifespan even without a sudden failure. Smaller residential turbines generally have proportionally lower absolute costs but also lower absolute revenue, so the same profit arithmetic still applies.
Why might a turbine generate a lot of energy but still show a loss?
Because profit depends on the relationship between the sale price per kWh and the operating cost, not on energy output alone — a turbine generating substantial energy at a low sale price, or facing unusually high maintenance or lease costs, can still post a loss even with strong physical output. This is exactly the scenario in this calculator's third example vector: 20,000 kWh sold at $0.15/kWh generates only $3,000 in revenue against $4,000 in costs, a $1,000 loss.
Does this calculator include the upfront cost of buying and installing the turbine?
No — this calculates a single year's operating profit from energy sales minus that year's running costs only, not the capital cost of purchasing and installing the turbine in the first place. Estimating a full payback period or lifetime return on investment requires comparing this annual profit figure against the turbine's total upfront installed cost separately.
What sale price per kWh should I use?
It depends on how the turbine's energy is sold or used: a utility-scale turbine under a power purchase agreement uses the contracted rate, a turbine selling into a wholesale market uses the prevailing wholesale price (which can vary significantly by time and location), and a small turbine offsetting a household's own electricity use effectively 'sells' at the retail rate that usage would otherwise have cost.
How does wind variability affect the annual energy figure I should enter?
Annual energy generated already needs to reflect a full year's variation in wind speed, not a single favorable day's output, since wind speed (and therefore power, given the cubic relationship) swings considerably hour to hour and season to season. Turbine manufacturers and wind resource assessments typically provide an estimated annual energy production figure that already accounts for a full year's expected wind distribution at a given site.