Wind Turbines VS Temperature

Wind energy is one of the most promising energy sources in years to come. As wind energy capacity grows, however, debates about their impact of raising temperatures are now prevalent. People started to worry about it and began to oppose the construction of wind farms.

The cause of the temperature change is the mixing of warm and cool air in the atmosphere in the wake of the turbine rotors. As the rotors turn they create turbulence, which pulls upper-level air down towards the surface, while surface air is pushed up, causing the warmer and cooler air to mix [1]. Researchers studied temperature data from multiple wind farm locations and also conducted computer simulations. They found that the wind turbines impact the temperatures to drop near the ground [2]. Besides, data shows that wind speeds have indeed slowed over these three decades across the Northern Hemisphere [3].

However, none of these studies can give us a substantiated clear relationship between wind turbines and temperature raises. Furthermore, by carefully analyzing some of these studies, we can draw an opposite conclusion. I believe that the wind turbine impacts, if any, is weak to be so worried about.

Here are some research results showing the innocent of wind energy.

By the study of Vautard and his colleagues, increased vegetation (resulting from ex-agricultural), afforestation and changing landscape could account for 25–60% of the observed stilling in wind speed [3]. In addition, urbanization may have more impact than wind turbines. Further, wind speed data of only thirty years is too short to draw any conclusions like wind farms slow down worldwide wind speed. Therefore, wind turbines are not a major reason for wind stilling.

Secondly, in paper [4] published in Atmospheric Chemistry and Physics, Wang and Prinn from MIT built a model and simulated the wind farm impacts. They suggest that using wind turbines to meet 10 percent of global energy demand in 2100 could cause temperatures to rise by one degree Celsius in the regions on land, but wind turbines installed in water could cause a drop in temperatures by one degree Celsius over those regions. Which means, by building wind farms offshore, wind turbines will not cause temperatures to rise. And offshore wind farm is one of the main trends of wind energy. Based on their result, a reasonable distribution of wind farms offshore and onshore will even contribute to the drop in temperature.

Thirdly, analysis of Kelley’s data provided observation-based evidence of the daytime cooling and nocturnal warming effects of wind turbines, which corroborates Roy’s modeling studies [1] (Neil Kelley, a principal scientist at the National Wind Technology Center; Somnath Baidya Roy , an atmospheric scientist of the University of Illinois at Urbana-Champaign). “For most regions, the mean temperatures may not change by much because the warming and cooling effects may cancel out,” says Roy [5]. These cancelations do not change mean temperatures by much even in wind farms, so there are no reasons of causing a global temperature raise. They are, at best, result to a milder climate regionally, which what we desire for.

Finally, if we take greenhouse effect into account, wind turbines are definitely not that good at raising temperatures as conventional energy.

After all, even if we assume wind turbines might be able to cause temperatures to rise, still it is too soon to slow down the construction speed of wind farms. There are two strategies to mitigate wind farms effect [1]. The first is to develop low-turbulence rotors that would result in less vertical mixing of the air and would also be more efficient for energy generation. The second strategy simply involves locating the turbines in areas that already have a turbulent atmosphere so the consequence of turbulence from the rotors in minimal.

 

[1]  http://www.gizmag.com/wind-farms-affect-local-temperatures/16582/

[2]  http://www.aboutmyplanet.com/environment/study-wind-turbines-cause-temperature-changes-on-ground/

[3]  http://www.nature.com/news/2010/101017/full/news.2010.543.html

[4]  http://www.atmos-chem-phys.net/10/2053/2010/acp-10-2053-2010.html

[5]  http://www.scientificamerican.com/article.cfm?id=how-wind-turbines-affect-temperature

 

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