You've probably heard the spin on wind: It doesn't create greenhouse gases when creating electricity, won't spill into a waterway like the Gulf of Mexico or Kalamazoo River, and doesn't require wars in far-off lands to secure supplies. But wind can affect local climates, making it cooler in the day and warmer at night, according to research from the University of Illinois. The lead researcher, U of I atmospheric sciences professor Somnath Baidya Roy, worked on the study with Neil Kelley, a principal scientist at the National Wind Technology Center. Roy had earlier proposed a model describing the local climate impact of wind farms. Kelley had collected temperature data from a wind farm in San Gorgonio, California, in 1989.
Side by side, the model and data confirmed each other.
"The study found that the area immediately surrounding turbines was slightly cooler during the day and slightly warmer at night than the rest of the region," according to a description on ScienceDaily.
According to Roy, when turning turbine rotors generate turbulence, upper-level air is pulled down toward the surface, and surface-level air is pushed up. The difference between warmer or cooler temperatures in a wind-farm area is the location, he says. In the Midwest, where most wind farms are located on agricultural land, a nighttime warming effect could provide frost protection and slightly extend the growing season.
But warmer climates aren't necessarily a good thing. The researchers are using the study to suggest new designs for low-impact, more-efficient wind turbines that will have less of an effect on local climates. They've also identified already turbulent regions of the world, including the Great Plains and parts of Europe and China, where wind farms aren't likely to have much of an effect on local climate.
Will this study have a negative or positive impact on wind development in the U.S.? On one hand, it says wind power changes climates. On the other hand, this isn't the same kind of global climate change brought on by coal and car exhaust, and wind power surely does more to mitigate the effects of greenhouse gases than it does to warm up local farmland.
Findings from the latest study are to be published in the Proceedings of the National Academy of Sciences.