Wind energy facilities have grown in popularity as one method to reduce fossil fuel use, but does extracting energy from the wind, actually cause the planet to gain warmth? Wind has always cooled the earth, but as more wind energy is harvested, does this inadvertently increase the globe’s temperature and reduce soil moisture by reducing the mixing of air at and above the earth’s surface? U.S. and German studies are included in this article to validate this idea.
Background:
Harvard’s Lee Miller and David Keith published their 2018 study in the academic journal Joule that created a high-resolution climate model of the continental United States, filled with sufficient wind turbines in the middle of the country to provide 100 percent of current U.S. demand. Their results showed that the continental U.S. got about 0.2°C warmer, on average, with the turbines in place, while within the wind-turbine-hosting region, the temperature increase was more like 0.5°C. That falls roughly in line with previous real-world measurements around wind farms.
It found the mixing of warmer air and cooler air results in a temperature increase of 0.54 degrees Celsius (0.97 degrees F) in the areas where the wind turbines would be located.
The 2018 study found that wind turbines cause significant local increases in surface temperatures in the areas where they are located. Wind turbines cause local temperature increases at the surface of the earth by causing air to mix throughout portions of the atmosphere, and Minnesota would be one of the states impacted most by this phenomenon.
The study looks at what would happen if the United States tried to obtain all of its energy from wind turbines. It found the mixing of warmer air and cooler air results in a temperature increase of 0.54 degrees Celsius (0.97 degrees F) in the areas where the wind turbines would be located. The amount of warming experienced in some regions would be even greater, as Southwestern Minnesota could see a temperature increase of 0.6-0.8 degrees C due to wind turbines, while Northeastern Minnesota would see an increase of 0.3-0.5 degrees C.
The study demonstrated that the warming impact of wind turbines is immediate, and highly localized. Although the benefits of reducing carbon dioxide emissions are global, the temperature impact is local.
The core problem is that wind turbines generate electricity by extracting energy out of the air, slowing down wind and otherwise altering “the exchange of heat, moisture, and momentum between the surface and the atmosphere,” the study explains. That can produce some level of warming.
Miller and Keith calculated the global warming avoided if the US, and every other country, eliminated its power-plant emissions by 2080, the avoided warming in the US in 2100 would actually be roughly equivalent to the added local warmth caused by the wind turbines.
According to the study, wind turbines measuring between 100 and 150 meters (328 feet to 498 feet) operating at night can pull down warmer air from as far as 1,640 feet in the air down to the surface, warming the surface of the earth, where it would impact the people, plants, and animals living near the turbines.
On a calm night, the maximum surface cooling can take place. But on a windy night, some warmer air is mixed downward to the surface, which prevents the temperatures from dropping as quickly as they would on a clear night. Therefore, forecast slightly warmer temperatures for a windy night than for a calm night.
Figure 1 shows the temperature response to benchmark wind power deployment of 0.5 MW/square kilometer. Maps are the 3-year mean of perturbed minus 3-year mean of control for 2 meter air temperatures. Figure A (top) shows the entire period with the wind farm region outlined in black and present operational wind farms shown as open circles. Figure B (lower left) shows the daytime results. Figure C (lower right) shows the nighttime results. The wind farm region experiences warmer average temperatures in Figure A, with about twice the warming effect at night compared with during the day.
Figure 1 – Surface Temperatures Reaction To Wind Turbines
Wind Farm Impact On Minnesota Emissions;
The orange dotted line in Figure 2 shows surface temperature increases in the areas with wind turbines, and the orange solid line shows the temperature impact of wind turbines on the entire continental United States. The blue and grey shaded areas show the differences in surface temperatures in the United States from reducing our national emissions.
Figure 2 – Impact Of Wind Turbine Surface Temperature Change, 2020-2100
According to the Minnesota Pollution Control Agency, Minnesota emitted about 150 million metric tons of greenhouse gases in 2016. Using the same logic used by the Obama Administration to craft the Clean Power Plan, if we completely eliminated all of these emissions to zero, it would avert only 0.004 degrees C by 2100, which is an amount far too small to measure, as shown in Figure 3.
The amount of global warming averted from reduced emissions in the U.S. (0.004 degrees C) would be 138 times smaller than the warming Minnesota would incur from building out wind turbines to power all of our electricity use (0.54 degrees C), as shown in Figure 3.
Figure 3 – Minnesota GHG Emissions, 1990-2016
As is apparent in Figure 2, surface temperatures in the United States increase more due to wind turbines mixing air in the atmosphere than would be offset by reducing emissions, and especially true in areas like Minnesota.
The only time that reduced emissions might impact surface temperatures more than the wind turbines, themselves, is if the entire world reduces their carbon dioxide emissions.
German study of wind turbines and increasing drought:
A German study by Wang et al (2023), suggests that its 30,000 industrial wind turbines are causing regional droughts of the conventional kind (as in a lack of precipitation, not a lack of wind). Northern Germany, for example, has a high concertation of wind turbines and has seen an unusual dry spell since 2019. The Wang study confirms the earlier model simulations of wind-park-made climate change, e.g. by Zhou et al (2013).
The German online SciFi site presents one chart depicting the wind energy installation concentration over Germany as shown in Figure 4. The North Sea region has an extremely high concentration of installed wind energy capacity. Conversely, Southern Germany has a very low concentration of installed wind energy capacity.
Figure 4 – German Wind Farm Sites
Figure 5, depicts the ground moisture across Germany in 2019 where the left side shows the moisture anomaly down to a soil depth of 25 cm while the right chart shows moisture anomaly down to depth of 1.8 meters.
The redder the area, the drier it is. Germany’s drought happens to be worse in the regions with lots of wind turbines.
Figure 5 – German Soil Moisture At 25 cm and 1.8 Meters
Summary:
Wind energy farms generate renewable electricity, however, the three studies (Zhow 2013, Miller/Keith 2018, and Wang 2023), indicate they also change the local climate with both elevated temperatures at night and lowering soil moisture so key for food production.
The Wang study proves that soil moisture is reduced by wind farms not only downwind but also upwind. The much-publicized catastrophic climate change could now be caused by the introduction of wind turbines which increase surface temperature while drying out the underlying soil.
My intent is to raise concerns on the direction of our emissions reduction strategy as a nation and as a globe, to see the best solutions that are backed by scientific research and results, not solely based on emotions of the day.
The ability for scientists to debate the pros and cons of various strategies and technologies is key to eventually arriving at the right scientific, business, and environmental solutions. Having a “fair fight” that airs all concerns, concealing none, and is open to new ideas is the only way that our planet will arrive at the most optimal environmental solution.
The consuming public as the earth’s stewards should be asking these questions and requesting both the media and the scientific community to air all sides of the energy, emissions, and climate discussion.
“It is better to debate a question without settling it, than to settle a question without debating it.” Joseph Joubert
Copyright © October 2023 Ronald L. Miller All Rights Reserved
