Any clue how ERCOT vets the suppliers?
There are certain minimum requirements for a supplier to sell power into the market, and for the most part, anybody that meets those requirements can sell the power. The system is designed so that you can sell as much power as you can deliver if you can provide it at the lowest cost.
This has allowed innovation beyond imagination. It began with all the little companies offering co-gen plants back in the ‘90s. Plants that could quickly come on line to meet demand and then be efficiently idled when demand faded away. It has also enabled suppliers to bring wind and solar online, and some are working on battery plants, too.
The system works pretty well in most cases. Yes, we have had winter events before, such is 2011 when the SuperBowl froze. This though, was the first time since 1899 that ALL of Texas was hit by the weather. That is why it was unplanned. I am certain, many companies are adjusting their planning practices as we type.
I think it is up to each generator to vet the suppliers. ERCOT appears more to be a coop board created by the generating utilities to have some oversight in reliability.