Wind Turbine Estimator. LIKE and Share us: Google+: Calculate: Rated output power (kw). Annual Energy Output (kwh/year). Cost of wind power (k€/kwh). Annual Profit (k€). Return on Investment (%). Break even Point (Years). CO2 reduction (Tonnes/Year). Input: Rotor size. Wind Turbine cost (k€/kw). Wind turbine revenue (€/kwh). Turbine efficiency. Generator efficiency.