These Incredible Saltwater Batteries Are Designed To Store Renewable Energy

If we’re going to use renewable power in a big way, we’re going to need better battery storage. Because solar and wind are intermittent sources of energy, they need to be backed up for when they’re not there, because, say, it’s night time.

Also, we’re currently wasting a lot of renewable power because we don’t use it at the moment it’s produced. Wind turbines are a bit like car factories that only sell half their vehicles; when there’s more power generated by turbines than the grid can handle, that power is “curtailed” and lost, rather than saved for another time.

There are few things that separate Aquion’s saltwater batteries–which are designed for renewable energy storage–from other new batteries. For one, they’re entirely non-flammable, unlike some lithium-ion batteries that have sometimes caught fire. And second, they’re easily disposed of (Jay Whitacre, who invented them, calls them the “first Cradle-to-Cradle batteries”). But perhaps the most important thing is that they’re available at all. There are dozens of interesting storage technologies in development these days. But the field is notorious for producing good ideas that, for one reason or another, aren’t quite ready for prime time.

“A lot of things that are put forward as the next thing in batteries actually have very unexplored scalability,” says Whitacre, a professor at Carnegie Mellon University’s College of Engineering. “Our team’s decision very early on was not to work on things that didn’t have an obvious path to manufacturing. We started from almost ‘how do I manufacture this?’ rather than ‘what material should I use?'”

The batteries are made from non-toxic materials like salt water, carbon and manganese oxide, and packaged into stackable modules. They don’t have the energy density of lithium-ion batteries (say, the ones used in electric cars) but they also don’t degrade as quickly and don’t need the same “thermal management” (i.e. equipment to make sure they don’t heat up or cool down too much). And, as already mentioned, they’re non-toxic, unlike lead batteries.

Aquion produces them from a former car factory outside Pittsburgh and already has several dozen customers. For example, a resort in Hawaii, Bakken Hale, has a 1MW battery stack, allowing it to completely rely on its solar panels for power.

Whitacre opened Aquion Energy in 2008, receiving venture finance from Kleiner Perkins Caufield & Byers a little time later. The company started manufacturing last year. Whitacre himself recently picked up the $500,000 Lemelson-MIT Prize, which recognized his ability “to connect laboratory discovery, policy impact and entrepreneurial savvy.”

Whitacre plans to use the money partly to pursue new fundamental battery research, though only the most practical kind. “I want to do work that is more useful near-term,” he says.