re: If Texas's central grid only relied on solar & wind energy, would anyone have electricity?

They are designed to handle these types of situations. There are massive facilities in ND, Alberta, etc. that run in these conditions yearly. The problem is with the deregulation in Texas, owners were not required to winterize their systems. This meant that companies who were bankrolling the projects decided that they didn't need to splurge for winterization...just another corner to be cut to save money in the deregulated market.