A wind turbine power curve can be modeled with different models. In this study, the Weibull distribution model was used to determine energy output of six commercial wind turbines ranging from 335 to 1,000 kW. Wind turbine power curves were modeled with seven power curve models, and energy output results were compared with Wind Atlas Analysis and Application Program (WAsP) results. To compare these models, the hourly average wind data measured at 50 m height in Turkey was used. Three models estimated energy output to be dramatically smaller for all cases and one model estimated energy output to be higher for all cases. In some cases, error of energy output estimation can reach to 80%.