Seems to be a price floor and/or set price.
> Texas’ Public Utility Commission, appointed by Abbott, raised the wholesale market price of electricity to $9 per kilo-watt hour — a 7,400% increase over the average 12 cents per kilo-watt hour — in response to rising demand. The hope was power generators would be enticed to produce more electricity.
“Last week, the price shot up to the legal maximum, set by the Public Utility Commission of Texas (PUCT), of $9 per kilowatt hour.” https://krdo.com/news/national-world/2021/02/24/how-texass-d...
It’s the market that chose that price, with sufficient generation is would have stayed at normal rates.
This seems to be contradicted by another source:
>The PUC met Feb. 15 to address the pricing issue and decided to order ERCOT to set prices administratively at the $9,000/MWh systemwide offer cap during the emergency.
>"At various times today (Feb. 15), energy prices across the system have been as low as approximately $1,200[/MWh]," the order states. "The Commission believes this outcome is inconsistent with the fundamental design of the ERCOT market. Energy prices should reflect scarcity of the supply. If customer load is being shed, scarcity is at its maximum, and the market price for the energy needed to serve that load should also be at its highest."
https://www.spglobal.com/platts/en/market-insights/latest-ne...
The key thing to note is that in the second paragraph, the utility commission thought the free floating price of $1200 was too low, and bumped it up to $9000 to "reflect scarcity of the supply".
What your referencing is points in the day when the price fell because rolling blackouts where intentionally created. “If customer load is being shed, scarcity is at its maximum, and the market price for the energy needed to serve that load should also be at its highest.” That’s saying if rolling blackouts are implemented then the price should be at the limit. Grid operators can’t simply turn off more people’s power to reduce the demand arbitrarily below the limit. So, prices where adjusted retroactively.
As to why that’s relevant, Grid operators are stuck with the bill. If they can maintain normal prices by simply cutting off everyone’s power to avoid losing billions that’s what their going to do. But, the are not allowed to arbitrarily cut people’s power because they dislike the current wholesale rates.
Again, choice was made about this storm, just enforcement of existing rules.