Coyote Blog

As a train enthusiast, I have to admit this sings to me.  I give them double points for being honest that their technology is not yet economic

The wind doesn't always blow, the sun doesn't always shine. So utilities are in search of ways to store surplus energy when they've got it, so they can distribute it later, when it's needed.

The most "duh" approach to energy storage is very big batteries like the ones Elon Musk peddles, which are poised to become a lot cheaper in the next five years. Pumped hydroelectric facilities are another option. Or you can move compressed air around underground caves. But none of these options has emerged as the best way to fix the grid.

Then there's rail energy storage, which is about to get its grand debut. In April, the Bureau of Land Management approved an ARES—that's Advanced Rail Energy Storage—project, conceived by a Santa Barbara-based energy startup called, well, ARES. By 2019, ARES operations head Francesca Cava says, the facility will occupy 106 acres in the excellently-named town of Pahrump, Nevada. By running a train up and down a hill, ARES can help utilities add to and subtract from the grid as needed.

It's a wonderfully simple idea, a 19th century solution for a 21st century problem, with some help from the abundant natural resource that is gravity. When the local utility's got surplus electricity, it powers up the electric motors that drag 9,600 tons of rock- and concrete-filled railcars up a 2,000-foot hill. When it's got a deficit, 9,600 tons of railcar rumble down, and those motors generate electricity via regenerative braking—the same way your Prius does. Effectively, all the energy used to move the train up the hill is stored, and recouped when it comes back down.