Yeah that is true, the electrical grid in the US has to be manually maintained in near real-time. Honestly it shouldn’t as a computer could handle this with no problems at all, but the systems to control that are not in place. Most power plants require power from elsewhere to run, with the exceptions of PV Solar, and some windmills the small ones not the big ones those require power to position themselves. Nuclear, forget about it, if the grid failed the plant would instantly go into standby followed by an automatic shutdown.