On February 28, 2008 a sudden drop in West Texas wind threatened to cause rolling blackouts. Grid operators narrowly avoided rolling blackouts and ordered a shutoff of power to so-called interruptible customers, which are industrial electric users who have agreed previously to forgo power in times of crisis. Imagine the crisis if Texas depended on windmills for 20% of their electricity as Obama wants.
Boone Pickens' Pampa Wind Project is just one wind farm located within one CREZ, and the CREZs are all over west Texas.
In Jan, Texas PUC awarded contracts to a number of transmission lines companys to build 2900 miles of lines to circulate among the CREZs and deliver the power to both DFW and San Antonio. And this doesn't include those CREZs in southwest Texas.
It is interesting that as a cool front was moving in and electrical demand was growing that the wind died out.
Coal and nuclear backup power will not respond well to unusual increased loads like that. It would have been at least as bad had a coal plant failed, and much worse had it been a nuclear plant failure.
You can find fault with any energy generating source. What we have here is cherry picking of the worst faults of wind and comparing them to the strong features of coal and nuclear power. That is the classical apples to oranges.
Grid operators use the best features of each generating source to offset the dissadvanteges of the others.