The way I understand it, that it was freezing cold and very windy , so that the turbines froze and wouldn’t move. Well that’s one part anyway.
If I’m understanding the article correctly, it sounds like NATURAL GAS was the bigger problem. In particular, the use of natural gas for both home heating and for electrical power generation is what caused the 1989 situation he describes.
When the big cold front moved through Texas, behind it followed an enormous pool of very cold air. It was in a high pressure center. Those conditions result in no wind for a period of days. It is common.
Some wind turbines may have froze. The biggest problem was there was no wind to spin the turbines.
Wind stopped producing power.
Then there was a huge demand for power, because of the cold.
The system could not handle it, because, as wind power was relied on for more and more power, not enough reserve capacity in nuclear and fossil fuels was built to compensate for the unreliable wind power.