Renewable wasn't the issue. The renewables are outperforming what was expected. However, renewables are like 4% of the total energy generation. ERCOT lost about 40% of its total generation capacity.

Almost all of the ERCOT shortfall was loss of thermal generating capacity--mostly natural gas. The natural gas was shunted to heating because those contracts are fixed and higher priority (market failure). Also, some of the natural gas lines, wells, and pumping stations froze (planning failure).

ERCOT lost more than 35% of its natural gas generating capacity. This was everybody cutting corners and finally getting burned.