Windpower limit?

[Randal Kerr]

Can anyone tell me if anyone knows if you pull millions of megawatts of energy out of the wind will it ever change the balance of the weather. When will that have as an effect to the climate? Seems it could have an effect worse than coal for the long term, but just speculation. If the wind slows what effect does that have on the local environment. If wind energy plants took a million megawatts out of it in the form of potential energy. Could that cause tornadoes in the middle of the states, draughts, fire's, flooding? I live in eastern Washington. Windmills by the hundreds. First year ever in 50 years we never had chinook winds after a snow, . Has to have an effect at some point. What is the limit before affecting some sort of change. There has to be a cap, but does anyone really know what that is?

[Rob Beckers]

Randal, interesting thought!

IMO, no, it won't make a measurable difference even if you plastered the entire earth's surface full with wind turbines.

Imagine the earth's atmosphere, in 3D: It's a heck of a lot of air from zero to (say) 30km in height, and it's all moving around. The amount of kinetic energy contained in there is pretty large (the understatement of the year). Wind turbines operate in the first few hundred meters of that atmosphere, and only affect that puny little bit of air contained in that layer, in comparison to the total contained in the atmosphere. Given time and motivation I could calculate how much air we have in the atmosphere in mass, calculate an order of magnitude of kinetic energy contained by using average wind speeds for layers, and the effect of taking about 2/3 of that energy out of the first 100 meters. I have a strong feeling it will be negligible...

Another way of looking at this is that we already very greatly affect the bottom layer of the atmosphere, and always have: The wind is constantly being slowed down by terrain, which takes massive amounts of energy out of that lower layer. Plastering the surface with wind turbines just moves that layer up a little bit, that's all.

For what it's worth..

-RoB-