I recall them saying 300 million without power, and saying the west coast was affected.
But even if the north american grid went down, that wouldn't affect the rest of the world. And I don't know if a US power outage would cause Canada's grid to be affected.
It has in the past. The US and Canadian grid is connected.
https://en.wikipedia.org/wiki/Northeast_blackout_of_2003
http://www.geni.org/globalenergy/library/national_energy_grid/united-states-of-america/graphics/nercmap-2006-04-07.jpg
A small nuclear device detonated in the upper atmosphere or an x class solar flare could knock the electricity out on an entire continent for years. It would fry every transformer on every electrical line. Not only would it take a long time to replace each transformer, they would all need to be built from scratch before installation.
By then, the cooling pools that store used fuel rods would have evaporated and we'd all be irradiated anyhow.
Sweet dreams! =)
I know it wasn't central to the plot, but I'm not sure what happened in Europe or Asia.
I've been reading the book, the book has a much more drawn out backstory about endless global war and civil breakdown before the total collapse of power. The movie doesn't go into that, it just has things running smoothly one day and everything down the next. However I do appreciate the fact that this didn't extend the movie by bringing this plot line into the film .
I would have liked to know that also.
😎