Can you elaborate because I don't understand how can absence of electricity cause billions of death.
Lights go out, you have no illumination in the cities, road accidents go through the roof!
There are no phones anymore, you can't call the firemen, the police the ambulance!
Ac no longer functions, you have thousands die of heat!
Going more seriously, hospitals are out of order, every single machine there from CT to RMN scans is out of order, and every life support machine is done.
But the biggest killer would be the absence of fridges, millions of tons of food will spoil, people will no longer be able to preserve that much food, and we will need to waste an incredible amount, or simple put we will not be able to feed the population anymore without a way to conserve what we produce now!