The Nissan Leaf may look like a car, but it turns out it will soon also be an emergency power generator on wheels. The automaker just took the wraps off its new "Leaf to Home" system in Japan this week, which promises to let you send power stored in the car back to your house in the case of an outage, or even back to the grid (letting you charge the car during off-peak hours and profiting when demand is high, for instance). Of course, that also requires more than your basic charging station (this one ties directly into your home's electricity distribution panel), and it's not quite ready for consumer use just yet -- Nissan expects i