Texas and ERCOT (Electricity Reliability Council of Texas) tries to maintain a ~12% reserve.
Plant maintenance was schedule well before the 20 year cold snap and had to be approved by ERCOT. Several plants were already down, then 3-4 more tripped off-line due to not being able to run in the cold. Believe it or not, the non-peak season is NOW.
There are 3 power plants being built within a stones throw from here. 2 coal, 1 nuke. Right now they are in the permitting process but they are proceeding. Plus there have been several natural gas fired plants built within the last decade. Probably too many actually, as it drives up the cost of natural gas but since NG burns MUCH cleaner they are way easier to get built.
My belief is that electric cars will have very little effect on the grid because most of them will charge at night while you are sleeping. They will probably be tied into smart chargers that can shut down due to demand, and there is even talk of back-feeding the grid with reserve power stored in the thousands of cars that will be plugged in.
In fact, if you think about it, electric cars will be a boon. Since there is already little demand at night most of the power plants have to cut back to a smaller rate. But if electric cars pick up the demand most of them could sell power that would otherwise not be needed. Electricity replaces gasoline. Sure, a person or two will plug in and charge at work during the day, but I assume that the vast majority will need to wait until they get home to charge. I would buy electric stocks if you believe that electric cars will be the future.
In the end, it was a minor inconvience. Yes, we had rolling blackouts for maybe a day or two. It is a once in a 15 year event here. Better to have this happen now than in June, July, or August. I'm proud to be a Texan and I'm glad we keep our grid separate.