Wind turbines are quite efficient at converting wind energy into electricity, with the peak efficiency being around 44-48% at the design wind speeds (typically between 6-9m/s). At higher wind speeds the efficiency drops as more and more wind is ‘spilled’ to avoid overloading the wind turbines and noise.
This compares favorably with coal fired power stations, which typically have efficiencies between 25-36% (meaning only 25-36% of the energy in coal is converted to electricity).
What is the difference between wind turbine efficiency and capacity?
Capacity describes how much a wind turbine produces every year with what it could theoretically produce if the wind blew very strongly all the time. Capacity factors for wind farms in Australia vary between 25 to 50% with most wind farms achieving 30 to 45%. The capacity factor is not just a function of wind speed but also the relative size of the rotor to the generator. For instance, in the same wind resource a 2 MW wind turbine will produce more electricity if the 2 MW generator is paired with a rotor that has a diameter of 100 m compared to one that only has 80 m. However, if the wind is very strong or cyclonic conditions occur on a site, one may not be able to use a very large rotor as the ultimate or fatigue stresses on the turbine could become too high.
How much energy does a wind turbine produce?
Each megawatt hour (MWh) of wind energy generated replaces the production of that MWh by another source, which in Australia in 2024 is still predominantly coal fired power generation. Hence, for every MWh produced by a wind turbine about one tonne of greenhouse gases (and their resulting impact on our climate) are not produced by other generators.
In typical conditions, each wind turbine will produce between 2.6 million and 3.9 million kilowatt hours of electricity per installed MW per year. So, a modern 6 MW wind turbine will produce between 15.6 and 23.4 million kWh per annum, which is equivalent to the consumption of between 2,800 to 4,200 average Australian homes.
Learn more:
- How Much Energy Does a Wind Turbine Produce? (Universal Technical Institute)
- Watt’s Watt? CEC explainer to wind energy Watt’s watt? A guide to renewable energy capacity and generation. | Climate Council
