“We use no water, burn no fossil fuel, produce no emissions, and use no hazardous or environmentally troubling materials like lithium,” ARES CEO James Kelly told Seeker. “We are excited to be a green storage solution that can enable higher penetration of intermittent renewable resources — like wind and solar — in the US and around the world.”
Pushing rocks up a hill might seem like a curiously low-tech approach to energy storage, but Kelly said that this very simplicity is what gives rail energy storage an edge. Building a railroad loop is a lot simpler than maintaining a giant battery farm, and the ARES system can easily use repurposed locomotives and freight cars. An ARES site can be quickly and cleanly decommissioned and restored in months rather than years or decades, Kelly said.
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None of this matters unless the system is efficient. Rail energy storage has about an 80 percent efficiency rate, meaning that the descending railroad cars can output 80 percent of the energy that was initially used to get them up that hill.
That's better than pumped-storage hydroelectricity, Kelly noted, which typically runs in the 60 percent range. Batteries can return a higher efficiency, but their capacity degrades over time.
“The real question is how much you get out when you need the energy,” Kelly said. “If you discharge your storage batteries tomorrow, you will probably get 90 units out. If you discharge in six months, you may get 40 or 50 units. ARES units have essentially infinite cycles with no degradation.”
“What we've done with ARES is harness the inexhaustible, entirely reliable power of gravity,” he added.
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The company currently runs two facilities, a testbed operation near their headquarters in Santa Barbara, Calif., and a new installation outside the town of Pahrump, Nevada.
In April of last year, the Nevada Bureau of Land Management granted environmental approval and a land lease to ARES for its first commercial operation. Construction on the Nevada facility will begin early next year and will initially help local utilities make small adjustments to the regional power grid.
Once the facility is fully operational, it will have a total power capacity of 50 megawatts — enough to help renewable energy providers manage their intermittent energy problems and better compete with coal and gas facilities.
According to Kelly, ARES currently holds an exclusive patent on its rail energy storage system in the US and 52 other countries, including the European Union and, as of last week, China.
“ARES has also recently received unsolicited requests to consider applications of our technology across the US, in Australia, China, Europe, South America, and South Africa,” Kelly said. “It's an exciting time.”
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