Wind turbines provide a large proportion of the world’s renewable energy, yet they also face opposition, mostly due to claims that they cause deaths to birds that fly through the wind farms and are swatted out of the air by the huge spinning blades. Another point has recently been discovered which could be used by the anti-wind lobby; that it changes local weather patterns, enough to even change local habitats.
A study by Fernando Portée-Agel, from the École Polytechnique Fédérale de Lausanne in Switzerland, which was published in the journal Environmental Research Letters, has looked into the effects of the down drafts created by wind turbines on the local environment.
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Along with his colleagues he created a scale model of a wind farm inside a wind tunnel and then measured the changes in temperature and humidity as a result of the turbines activities and their impact on the movement of natural wind in the area.
When positioned in neat rows the downdrafts created by each individual turbine begin to superimpose one on top of the other, multiplying the effects to such a degree that it changes the way heat and moisture is lost from the land.
This can cause positive changes, such as in Iowa, USA, where crops planted below the turbines are kept cool during the summer; or negative changes where the moisture is removed from the land which dries and causes the crops to wilt.