Wind Turbines as Global Air Conditioners

What if wind turbines could change our weather? Would it be possible to use them to cool ourselves on a hot day, or clean a swell of dirty air? Here, I'll propose just that--using MW-scale turbines as coastal or even global air conditioners. If validated, this idea could be incorporated as a criteria for siting turbine farms and achieving benefits beyond renewable energy.

To answer the lede, wind turbines do affect local climates [1]. Spinning blades disturb natural air flows, creating turbulence and downstream mixing. Like stirring a bowl from the microwave, this mixing redistributes heat to warm the surface below and the atmosphere above [2]. Some large-scale climate models caution that the reduced emissions from widespread turbine use might be partially offset by the induced warming [3].

Turbine induced warming occurs because normal atmospheric conditions hold the warmest air at the surface and cool with increasing elevation. When the lowest air is the warmest, the turbine's turbulence warms the surrounding area. This normal temperature profile arises due to the air pressure decrease with increasing elevation, as temperature and pressure measure related molecular properties of the air [4].

Defying vertical norms, "temperature inversions" occur when cold air sits under warmer air [5]. Temperature inversions can occur over cold-waters, when air gets stuck in valleys, or even when cold air is blown to a warmer region. If placed within temperature inversions, turbines would mix around colder air to conceivably cool the downstream areas.

Some intriguing sites qualify. Temperature inversions are common over the fog-spewing Pacific currents, occurring over 90% of the time in summer and over 50% of the time in other months [6]. Frequent temperature inversions are similarly observed along the cold-water coasts of India and Southeast Asia [7, 8]. Offshore turbines at these sites might cool the coastal communities against a warming planet, while supplying clean energy. Moreover, offshore wind is a more reliable generator than onshore wind [9] without precluding other beneficial lands uses.

The intrigue of turbine-induced air conditioning extends inward from the coasts. Temperature inversions are also common in valleys, where they pose problems due to trapping airborne pollutants. For instance, temperature inversions in Salt Lake City were correlated with asthma-related hospital visits [10]. Valley-facing turbines at these sites might mix the stagnant air and clear it of pollutants. By also displacing dirty energy sources, these turbines would fight pollution on multiple fronts.

Improved vetting of this theory requires a two-step research project: (i) quantification of the cooling properties of spinning turbines within temperature inversions, and (ii) incorporation of the turbine-induced cooling into a comprehensive region-scale climate model. Such a plan has been discussed with folks at the University of Minnesota's Eolos wind research facility.

Some important caveats and last thoughts exist. Many people are rightfully wary of engineering a better climate. To that, I argue we have been "engineering" our climate to dire effects for over a century. In any case, spinning turbines could be turned off if negative effects were observed Finally, these same principles might permit the ice caps and arctic permafrost from staying frozen in an increasingly warm world.