So how will they prevent this in the future?
A final report will be made, but a couple of things that stand out - plants have done a great deal of winterizing in the last few years, but it seems that in many cases, the gas supply failed due to freezing issues at the wellhead. A little bit out of my wheelhouse, but if the gas isn't coming down the pipe, the plants can't generate power.
As for the windmills - my opinion on them is unchanged. They're a nice supplement, but they should never be relied on for firm customer load. They always need backup. Same with Solar.
I don't know all the plant issues from Sunday night, but a ton of generation came off line and threatened taking down the entire grid - that's why they did the emergency load shed.
I think that standards for weather-proofing plants are coming, rather than "guidelines". And, the gas well sites will have to winterize to deal with extreme weather. We may not see this extreme cold in Texas again for 100 years, or we might see it next winter. Best be prepared IMHO.