Elon Musk gets all the pixels for his new Powerwall battery system, but here's another cool battery that is making a splash. It's the Refrigeration Battery from Axiom. Apparently those giant coolers and fridges full of all that unhealthy frozen prepared food eat up 56 percent of a grocery store's electricity. The refrigeration battery, like the Powerwall, works by storing energy when power is cheap, smoothing out the demand curve. However it does it with water, not lithium.