Seriously, what are the feds gonna do? Start bombing power plants?
No, they'll send a sternly worded admonition about the rule of law, and then the EPA will sue in federal court.
Then the state should step in and say "Our citizens are not subject to this suit, and have been authorized by the state to ignore it. Molon Labe, or STFD. Our people need electricity and they don't need tyranny."