If windmills were used for all the country's electricity, would it change the climate?

[guizot]

I’ve heard it said that, in theory, at least, with windmills we could use the winds of the Great Plains to power the U.S. But wouldn’t such a large amount of energy absorbed from the winds alter how they affect weather patterns? Would it be at all significant? What kind of changes would be noticeable, if any?

[Swords_to_Plowshares]

Even if wind powered the entire US there would be vastly more trees than turbines in the US. I suppose you could look at how trees (both sparse and in forests) affect wind and draw a conclusion from there. My gut reaction is that’s there would not be a big difference at all.

[Una_Persson]

This was discussed with anger in the Pit recently. Here is a link to a single source which I found on the issue (I would summarize the results as “inconclusive, but doubtful” personally)

http://www.pnas.org/content/101/46/16115.full

[guizot]

@Una_Persson

This was discussed with anger in the Pit recently. Here is a link to a single source which I found on the issue (I would summarize the results as “inconclusive, but doubtful” personally)

http://www.pnas.org/content/101/46/16115.full

Okay, thanks. That’s what I wanted to know. Thank you very much.

[ZenBeam]

In that link, they model the effect of windmills as an increased drag coefficient, but don’t include effect of turbulent mixing of the atmosphere. They acknowledge:

Including the effects of turbine-generated turbulence might significantly lower the effective atmospheric efficiency by increasing turbulent momentum transport and thus inducing additional drag on the ground downstream of the turbines. Additional turbulence will also increase turbulent transport of heat and moisture (11). Both effects are ignored here, and thus, we may underestimate the climate impacts per unit electricity.

The abstract of Cite 11, Can large wind farms affect local meteorology? says:

The RAMS model was used to explore the possible impacts of a large wind farm in the Great Plains region on the local meteorology over synoptic timescales under typical summertime conditions. A wind turbine was approximated as a sink of energy and source of turbulence. The wind farm was created by assuming an array of such turbines. Results show that the wind farm significantly slows down the wind at the turbine hub-height level. Additionally, turbulence generated by rotors create eddies that can enhance vertical mixing of momentum, heat, and scalars, usually leading to a warming and drying of the surface air and reduced surface sensible heat flux. This effect is most intense in the early morning hours when the boundary layer is stably stratified and the hub-height level wind speed is the strongest due to the nocturnal low-level jet. The impact on evapotranspiration is small.

So there’s a little more info.

[Peremensoe]

I imagine the climate effect would derive from not burning fossil fuels.