A little over a year ago, Google partnered with IEEE to launch “The Little Box Challenge,” a competition to build a much smaller power inverter. In  July, over 100 teams submitted Technical Approach and Testing Applications to have their inverters tested at the National Renewable Energy Laboratory's Energy Systems Integration Facility in Golden, Colorado and 18 teams were selected to have their inverters tested. Click here to find out which teams are still in the competition.

When the competition was first announced, the Google Green blog said in part that a power inverter  is a “a picnic cooler-sized device used to convert the energy that comes from solar, electric vehicles and wind (DC power) into something you can use in your home (AC power). We want to shrink it down to the size of a small laptop, roughly 1/10th of its current size. Put a little more technically, we’re looking for someone to build a kW-scale inverter with a power density greater than 50W per cubic inch. Do it best and we’ll give you a million bucks.”