Air turbulence from giant turbines causes air temperatures to rise around wind farms, scientists say.
Researchers including Associate Professor Liming Zhou from the State University of New York examined conditions around 2,358 turbines at four Texas wind farms.
Writing in the journal Nature Climate Change, Professor Zhou and colleagues reported a temperature increase of up to 0.72 degrees Celsius per decade at wind farm locations, compared to nearby areas.
They also found the effect to be greater at night than during the day.
The study could help researchers better understand the impact of wind farms on local environments.
After discounting the impact of surface features such as vegetation, roads, light reflection and surface structures, the researchers concluded that the temperature change was caused by air turbulence generated by the turbines’ giant rotor blades.
“Turbine rotors were modifying surface-atmosphere exchanges and the transfer of energy, momentum, mass and moisture within the atmosphere,” they wrote.
The findings are based on nine years of satellite data covering an area of central western Texas, where some of the world’s largest wind farms are located.
The results match modelling studies showing wind farms can significantly affect local scale meteorology by increasing surface roughness, changing the stability of the atmospheric boundary layer, and enhancing turbulence in the wake generated by rotor blades.
Professsor Zhou and colleagues said a large enough wind farm could even affect local and regional weather and climate.
Climate scientist Professor Nigel Tapper, of Melbourne’s Monash University, is not surprised by the results.
“No matter what we do, any modification of the landscape will have an impact on air temperatures,” he said.
“The critical thing is that it’s a local effect and one we need to understand.
“If you were to use solar panels rather than turbines you would still have an effect.
“The question is whether that local effect is offsetting the generation of power from coal-fired power stations.
“Because fundamentally the impact of carbon dioxide emissions is having a global effect rather than just a local one.
“”I do believe in global warming and I believe we have to look at alternative energy.
“We need a portfolio of energy sources and wind farms will be one of them.
“It would be nice to do a similar study here, we would probably get a similar pattern,” Professor Tapper concluded.