There was a mini series several years ago, called "Revolution"(I think) where some secret Gov't "Nanobots" that were designed to disable the electricity in a small, localized area during combat, got loose and started replicating.
All electricity world wide ceased over night.

All cities were death traps. People fighting over food and water. Atlanta was depicted as being one of the worst
https://en.wikipedia.org/wiki/Revolution_(TV_series)