Back to the Future’s 1.21 gigawatts sounds huge, but is it? We compare different power levels of common objects to see how much energy a gigawatt really is.

  • No, an average nuclear plant outputs 1 GW. That means 1 GWh per hour or 24 GWh per day. Watt is how far you pull the handle for the tap, Wh is how much water comes out in an hour. So lightning is 10 GW, but for less than a second, which means the kwh is maybe in the hundreds somewhere, not anywhere near what a nuclear plant produces in an hour, let alone a day.

    But if you need a very short burst of electricity for something, lightning is indeed the best way to do it.