It's not about the average, it's about the abnormal peak usage. The grid is built to support the average, with a buffer to support expected peaks, and an emergency margin above that. Current peak demand exceeds previous predicted peaks by a considerable margin. When the peak cannot be met, you get brownouts. Also, if some capacity is now offline due to whatever reasons, the total peak they can support is less, and again, more brownouts. One way to reduce peak demand is to reduce unnecessary consumption, shutting down production plants, etc, during emergencies. Large consumers usually have that built right into their service contracts. Now, another aspect is you can usually buy additional power from neighboring jurisdictions to offset abnormal peak demand in your own region. However, right now they are all having their own peak demand issues. They are all in the same boat this time. If I had to observe anything, I'd say Texas has been pushing hard to draw in residents from other states for the past ten years, but failed to build the needed additional power capacity to accommodate that influx, and now they are in trouble. Gambled and lost the bet, so to speak.