Power plants matter, but nowhere near as much as the grid. It would simply collapse in 49 states if TX shut off a huge chunk of the power to Cali. Too interconnected and simply would not be able to handle the shifting load. (Not even going to get into the power phase issues except to say “Boom”!)
Again, this isn’t supposition. TX STOPPED that kind of cascading failure before. Causing one would be trivial...
I’ll throw a variable out for you on that one. Silicon Valley hackers versus Round Rock hackers fighting for control of Texas’ grid. That cyber war may be bigger than the gunpowder war.