Recently, we received a question from a follower, “How can a 50kW wind turbine produce more energy than a 60kW turbine?”
The short answer is: This can happen when the annual energy production (AEP) of the 50kW wind turbine is greater than the AEP of a 60kW turbine.
The rated power stated in kW can be a misleading method for describing wind turbines. Rated power is the wind turbine’s power output at a specific wind speed. This is the most accepted/universal way in which companies refer to the size and output of their wind turbines.
Rated power does not provide an accurate picture of a wind turbine’s energy output potential. A more accurate picture of a wind turbine’s performance, is annual energy production (AEP), measured in kilowatt hours (kWh), instead of power measured in kW. A kilowatt hour is the unit of power or energy, which is equal to 1000 watts operating for one hour. An estimate of AEP must take into consideration wind conditions over time to project the usable amount of energy produced in a year.
So it could be very possible that one company’s 50kW wind turbine has far greater energy output than a competitor’s 60kW. Ultimately, it is best to look at the AEP of wind turbines, rather than rated power, to get the most accurate picture of possible energy production.
For more information on rated power and annual energy production, you can view our PDF on Wind Turbine Investments: Determining Real-World Financial Returns, which goes into great detail about power vs. energy (Rated power vs. AEP).