No, there will be no net change in temperature, since the air at windmill height will cool off.
Cliff Mass Weather and Climate Blog
This blog discusses current weather, weather prediction, climate issues, and other topics
Saturday, October 6, 2018
Do Wind Turbines Enhance Global Warming? No!
There were a series of headlines in a variety of media outlets this week suggesting an unfounded and unphysical claim: that wind turbines might contribute to global warming. Some examples below:
 | | The Associated Press |
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 | | The Harvard Gazette |
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 | | MIT Review |
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These stories are based on an article entitled “Climate Impacts of Windpower,” by Dr. David Keith and Dr. Lee Miller, in which they ran the WRF model (the one I use) and added the impacts of a very large number of wind turbines over the central U.S. They found that the wind turbines caused a .24C warming over the U.S. due to the mixing of warm air down to the surface.
Now why does mixing of the wind in the vertical produce surface warming? Doesn't temperature cool with height?
The key issue is that frequently the surface is cooler than than the air above. This is particularly true at night when the earth radiates heat to space more effectively than the air above. In these cases we can get an inversion, air warming with height. Mixing due to the disturbance of the air flow by the spinning blades can mix warmer air to the surface.
This effect is no stranger here in the Northwest--have you seen the fans around orchards in eastern Washington? They are used to mix warmer air down to the surface to reduce freezing temperatures when the buds on fruit trees are vulnerable. Some vineyards have them as well.
 | | "Orchard-Rite" Wind Machines |
So one can cause small net localized warming at the surface by mixing the low-level air, but you are NOT warming the atmosphere as a whole, but simply moving warm air around.
Thus, wind turbines are not producing any net heating to the atmosphere and thus doing NOTHING to increase global warming. And the only time there is localized warming is when the surface is relatively cool!
Wind energy is am important technology in our quest to move towards renewable energy and a potent complement to solar energy, particular at night and in cloudy regions. It is unfortunate that some careless media reporting left an inaccurate impression of negative climate impacts of wind energy.
Posted by Cliff Mass at 10:28 PM
cliffmass.blogspot.com |
