In some cases it is because the consumer has opted for variable rates, essentially making a bet that net-net, variable rates will be less expensive than the fixed rates. Or that they would be able to shift usage to reduce usage during spikes. See: https://www.texastribune.org/2021/02/22/texas-pauses-electri...

Also see: https://www.ft.com/content/0e746280-e72c-4087-9c0d-df2a7af82...

Feb 2021 FT: "Bills mount in Texas power market after freeze sends prices soaring: Financial casualties emerge as grid operator Ercot requires billions in payments "