This is why the administration is talking to google. Google wants to connect us all to an electrical grid so our electricity can be monitored and rationed down the road.
By doing that, a smaller weapon could fry the grid. They wouldn’t have to launch something to impact the entire country. Feasible it could be done by sabotage of a few monitoring locations.
China could already knock out satellites. A coordinated attack that blinds us and then hits selected targets has the same impact and it could be brought back relatively quickly.
The Grid is a very complex control loop. That’s why a single mishap in New York; that only affects a small sub-station can bring the entire city to it’s knees. It’s happened not that long ago.
Your point is very well taken; you don’t need to destroy a power generation system, you can unbalance the load, and cause this instability to trip safety breakers - and if you do it ‘smart’ you can bring down a huge area, for long enough to really do some damage. And the damage need not be physical, you can do a lot of damage to the morale of the population by removing something they depend upon, and take for granted.