regarding "the wind doesn't always blow...", that's why the goal is 20% and not 100%. You have wind farms that SUPPLEMENT peak usage, not replace it. And no, we're not going to disrupt the "airflow of the atmosphere"...
I work for Iberdrola. We are, if not #1 now, vying for the world's #1 fleet of installed wind energy turbines.
Our US chief tells us that the US Great Plains have enough wind that if fully developed could power the US grid.
BUT pushing te energy to NY or LA from Iowa is damn near impossible. The line losses would be too much is the lines existed.
The times when the wind blows do not coincide with the times of peak usage. Thermal plants are required to keep the lights on and to make up the difference when thw demand exceeds supply of wind power. Thermal plants cannot move up and down quickly enough to make up for sudden changes in wnid energy. In the NW, Bonniville keeps the power curve steady by altering the flow of hydropower and the TVA can do that too, but all sectors do not have that resource.
Wind is not the total answer. It is one part of a diverse future power portfolio.
Chicago, Minniapolis, St Louis, Dallas, Memphis, etc could be substantially wind powered in the near future