Of course the ERCOT political appointees put out a release [1] blaming the wind, when the problem was the fossil fuel sources.

Why there was a projected supply shortage:

1. Expected: low wind production (as is normal on a summer day)

2. Unexpected: "...The problem is that they only expect 4.0 GW of thermal to be offline (see Typical planned and unplanned outages, thermal). FYI, thermal includes, gas, coal, and nuclear.

According to ERCOT, 12 GW of thermal ("dispatchable") is offline today." – quote from thread: https://twitter.com/AndrewDessler/status/1546528816272654337

[1]: https://dentonrc.com/news/denton_municipal_electric/grid-hol... (via https://www.texasmonthly.com/news-politics/renewable-energy-...)