That s complete bull.
Even If Texas was part of the western, or eastern interconnect there would not have been the infrastructure in place to handle this cold weather.
This was not just power producers not being able to operate their generation in this cold weather. This was gas suppliers not being able to supply fuel so the problem is not just electricity related.
Even If Texas was connected, the fact is that there was not excess energy available on either interconnect due to the nationwide cold snap. There was nothing to sell to Texas. Even if it was available there would have had to have been bulk energy transmission facilities in place.
The entire energy delivery infrastructure IE gas, electric is just not set up for these cold temperatues, and frankly 99.999% of ther time the residents of Texas benefit from this in lower rates.
This very same non cold weather tolerant systems is demonstrated visibly throiughout Texas. Just drive through the state and look at the water wells, with outside piping to get an idea of the challenges that occur during an extended cold snap.
If ERCOT wants to have a cold weather tolerant interconnect, they can do it, but it's going to cost every rate payer in Texas, every month, forever, and the cost will not be just a few dollars a month, and it's going to take years to make the changes.
Then you have the other issues that are related to the ice. ERCOT is responsible for Generation and Transmission in Texas, but local utilities are responsible for Distributing that energy. That distribution infrastructure is what created days long outages Vs "rolling blackouts" caused by bulk energy shortages. Ice builds up, and causes lines to sag into each other or break. Trees snap and fall into lines when they are ice loaded. Lots of bad things happen during a ice storm, and dam few of them have anything to do with federal regulation.
If this were simply a shortage of energy as some incorrectly claim then folks would have experienced rolling blackouts lasting X number of hours followed by a different area or areas being in the dark.
This is from a professional power grid operator and engineer.