This really is hard to imagine. Electricity in civilization is something I take for granted. There are some things that simply can't be off, such as life support machines, operating room lights during a heart surgery, 911 emergency systems, etc. There are also things like this: you show up at a hospital and they won't treat you because they can't verify insurance coverage in their computer systems. The list goes on and on.

It's easy to think about this type of thing from a healthy person's perspective, but for the sick and people in trouble, electricity suddenly going out can easily be fatal. So, we have electric generators, but eventually the fuel will run out. Also, I highly doubt all of the critical backup generators worked where needed for the 600 million people. I have to wonder, how many people didn't survive as a direct result of this massive power failure?

Let's see. For survival, a human at least needs air, water, food, and shelter. For a modern society of 600 million people, electricity can't be too far down on the list.