Since we are talking hypotheticals, an ideal scenario would be a nearly completely renewables approach where each household is its own self contained energy production center equippef with solar arrays, wind turbines, thermoelectric generators. Various means of production. And have either propane or diesel as a backup. Most importantly a big battery array for storing energy long term during bad weather.

Most household electrical wiring is redone for DC transmission and all consumer appliances possible are run straight on DC for optimal efficency. Energy efficent heat pumps for cooling and heating. energy efficent cooking appliances like induction heaters. Electric cars that act as backup battery banks would be awesome.

Humanity simply does not “stop” because we run out of non-renewable electrical energy. We did fine enough before the industrial revolution, the Amish do fine now, backwoods countrymen do fine now, and renewables + energy efficent consumer devices have improved a bunch.