Google Inc. (NASDAQ:GOOGL) opened its Little Box Challenge Tuesday, offering a $1 million prize to any inventors who can prove the ability to transform the power converters people use for their vehicles and home appliances into a renewable energy source.

Google first announced it would conduct the Little Box Challenge in May, but starting Tuesday, designers will be able to submit any ideas they have that could shrink power converters from their current size (roughly that of a picnic table) to about the size of a tablet. The winner, simply put, should expect Google to make it worth their while.

“Seriously. Of course, there’s more to it than that,” Google Green team member, Eric Raymond, said. “Especially when the big box is a power inverter, a picnic cooler-sized device used to convert the energy that comes from solar, electric vehicles & 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.”

The deadline to register is Sept. 30, 2014, with a full technical approach and testing application due no later than July 22, 2015. Google, which is teaming up in the contest with the Institute of Electrical and Electronics Engineers, advised that if there are enough quality submissions, up to 18 finalists will be informed of their selection for the final stage of testing.