2018-10-04: Research published today suggests that the power available from wind is much more limited than many experts thought, and that deployment on a larger scale could significantly raise temperatures over the Earth’s surface, as turbines alter atmospheric flows. The research highlights a painful but not altogether surprising reality: Even the cleanest renewable technologies come with environmental costs.
Research found that wind plants encompassing the largest areas had the lowest power densities, as expected. This figure implies that meeting current U.S. electricity needs alone would require wind farms to cover fully 12 percent of the U.S. land area. Wind power has physical limitations.
Miller and Keith found something even more surprising in another study that looked at a related question: What should we expect the climate impact of significant wind energy generation to be? Removing energy from atmospheric winds means those winds carry less energy afterward, moving more slowly, among other things.
simulations revealed that interactions of the turbines with the atmosphere would likely lead to a redistribution of heat in the lower atmosphere, resulting in a 0.54 degrees Celsius (0.97 degrees Fahrenheit) warming within the wind farms’ region itself, and an increase of 0.24 degrees Celsius (0.43 degrees Fahrenheit) over the continental U.S. This result, they note, actually matches up pretty well with recent satellite observations of local warming around wind farms operating in California, Illinois, Iowa and Texas. They also found that an expansive wind farm would need to operate for more than a century or so before the reduction of global carbon dioxide emissions would offset the local warming effect.
Miller and Keith also looked at U.S. solar farms, finding an achieved energy density about 10 times higher than for wind farms. Solar arrays in their study also led to much less local warming. There may be a good reason to shift future investments toward solar energy, as some big investors are doing already.