It all started with a tree and a power line in Ohio. Within hours, electricity was out for some 50 million people across eight states in the Northeast and parts of Canada. It's been 15-years since the 2003 blackout, one of the largest in history, which shut down trains, traffic lights, ATMs, refrigerators and everything else with a plug. So, how's our power grid doing today? Well, things have changed.
For one, there's efficiency.