Without the power grid we are right back to the dark ages in a matter of a few days. Except at least in the dark ages people sort of knew how to survive. Now, only a minority of people really know how to survive without modern conveniences.
The places that don't have the fallback ready access to fallback diesel genset, like rural South Sudan or Burundi, are pretty close to an end of the world scenario.
Don't romanticise disaster. If a developed country indefinitely lost power, a huge swathe of the population would die, starting with the infants, elderly, and chronically ill. Then hunger and disease would come for the rest. Nonsense ideas that we'd MacGyver or bushcraft our way out of trouble are infantile.