2014. After the event the government was advised that winterizing the powerplants needed to be done to prevent similar events in the future.
Instead, Texas did nothing for another 7 years, and then the same thing happened again.
This was wholly predictable: Texas running an independent grid doesn't have enough power import capacity to manage long-tail events, but also chose to manage them by ignoring them and damn the consequences - those consequences being Texan citizens froze to death in their homes (https://www.texastribune.org/2021/02/19/texas-power-outage-w...).