The usual wholesale price of electricity is around $0.11 per kWh. The retail price of electricity is around $0.16 per kWh. So you save about $0.05 per kWh used in an average month -- not bad! That's a free $20!

Until a "100 year" storm comes along, and makes the wholesale price of electricity $9 per kWh. Now instead of saving $20, you owe $8,800 more than usual.

Because electricity demand was too inelastic, the pricing signal was set extremely high by ERCOT. So folks go saddled with ~$8000 electricity bills for that month.

Because you get a $10,000 electricity bill?

As I understand it, there are two ways to purchase electricity in Texas:

1) a fixed rate per kilowatt hour, regardless of what the wholesale cost is. 2) a variable rate per kilowatt hour, which is wholesale cost.

If supply is up and demand is low, wholesale prices drop, so the customer pays less per kWh and ostensibly less per month. In that same vein, if supply is down and demand is high (like when power plants literally freeze and supply from other sources can only trickle in), wholesale prices rise and this increase is passed directly to the consumer.

On the other hand, fixed rate consumers pay the same per kWh regardless of whether the wholesale cost is high or low.

So when prices skyrocket to $9/kWh, wholesale customers are on the hook for it, but fixed rate customers will still be enjoying 10.98[1] cents (yes, that's $00.1098) per kWh because their utility provider has to deal with it.

[1] https://www.electricitylocal.com/states/texas/