It's 2020. You drive your plug-in hybrid electric car home at 6 p.m., plug it in, let it charge via the solar panels on your roof or the wind power coming from the grid, and you leave it charging until the morning. Sounds simple enough, right? It's not. Utilities have a long way to go before they're prepared for the impending onslaught of energy-sucking vehicles—and they might not all be ready in time.