Steps ahead: Liquid Batteries for Solar and Wind Power
a status report
reprint In an industrial park on the outskirts of Pullman, Wash., 10 white storage trailers sit side by side, neatly arranged in two rows. These are no ordinary storage units. Arranged on racks inside are the guts of a large rechargeable battery, the kind of device that can store and release utility-scale amounts of electricity. But this is no ordinary storage battery , either. In contrast with the typical lead-acid batteries used to start car engines or the lithium-ion cells that power electric vehicles — both of which are largely solid — this battery is mostly liquid. The chemicals that react to produce electricity are dissolved in water and circulated into and out of the heart of each cell, where the reaction occurs. For that reason, it is called a flow battery, and the one in Pullman, a demonstration project that will be tested over the next year and a half, is one of the largest in the world. It can store about 3.2 megawatt-hours of energy and discharge a meg...