Wind turbines are a great way to generate low-carbon electricity. But there might be a catch.
Just like sunshine, winds are forever present across much of the planet. They are generated naturally and thus can be harnessed as an inexhaustible resource. As a result, wind power is widely seen, and rightly so, as one of our best options in transitioning to low-carbon energy as we wean ourselves off fossil fuels.
But there might be a catch. We would need lots and lots of giant turbines to generate enough electricity to power our modern lifestyles with all our electronic appliances and gadgets. And those turbines could have an impact on how air flows in the atmosphere above, leading to an overall warming effect (albeit not permanently).
So say two scientists who have published a paper in the journal Joule. They explored a hypothetical scenario whereby enough turbines were installed in the US to generate all domestic electricity.
The scientists employed data collected from current wind farms in operation around the US to create a model that would calculate the effects if more similar wind farms were installed. To generate current electricity needs in the country, which is a sixth of all energy used domestically, the US would need approximately 16 times more wind power. The turbines would have to be located strategically in certain places and allowed to run simultaneously. Their collective churning of the air would disturb atmospheric airflow above them.
“We find that generating today’s US electricity demand (0.5 TWe) with wind power would warm Continental US surface temperatures by 0.24°C,” the researchers say, adding that this would be 10 times the effect produced by solar farms. “Warming arises, in part, from turbines redistributing heat by mixing the boundary layer,” the add. “Modeled diurnal and seasonal temperature differences are roughly consistent with recent observations of warming at wind farms, reflecting a coherent mechanistic understanding for how wind turbines alter climate.”
The warming effect, they point out, “is small compared with projections of 21st century warming, approximately equivalent to the reduced warming achieved by decarbonizing global electricity generation, and large compared with the reduced warming achieved by decarbonizing US electricity with wind.”
What this means is that wind farms themselves could impact local climates, although this impact would not come in the form of permanent climate change per se. Rather, the turbines would cause atmospheric air to circulate in different ways, thereby leading to measurable warming at ground level.
“Even with renewable technologies there are some climatic impacts,” said Lee Miller, a postdoctoral fellow at Harvard who cowrote the new study. Yet he has warned against the results being willfully misused by climate sceptics. “I have no doubt that these results will be misconstrued and misinterpreted,” he lamented, stressing that renewables like wind are still far more preferable to fossil fuels when it comes to energy generation.