"Most of the power knocked offline came from thermal sources, Woodfin said, particularly natural gas."

So natural gas and other thermal sources (i.e., coal and nuclear) created most of the problem.

Wind power is actually potentially a very good solution for occasional cold spells, because extreme colds usually comes with high winds. Of course you have to design your turbines not to freeze.

While true (and I'm not saying you don't know this, more just pointing it out), wind works great in cold climates. We've done our homework on this one already.