Narrator in “Pilot”

What you gotta understand... is things used to be different. We used electricity for everything. For our computers, our phones, even to grow food and pump water. But after the Blackout, nothing worked... not even car engines or jet turbines. Hell, even batteries. All of it, gone forever. People starved. Sickness without medicine. Fires without fire trucks. Governments fell. Militias rose up. If you were smart, you left the city. If you weren't, you died there. So, what the hell happened? What caused the Blackout?