A California-based company, Advanced Rail Energy Storage (ARES), is providing grid-scale energy storage using small electric locomotives, according to a March 4 report by Interesting Engineering. And there is a system ready to go online in Nevada soon.
During off-peak hours, when energy draw is low, the company uses rail cars to push heavy concrete blocks to the top of an incline using excess power generated from distributed energy resource. To release the energy from storage, when demand is higher on peak, the company allows the cars to roll back down the slope – using gravity to generate power through their regenerative braking systems, IE said.
ARES claims that the system can respond to increase and decreases in demand in seconds. The company also has said that the system boasts charge/discharge efficiencies of 80 percent and can deliver constant power for periods of up to eight hours.
ARES conducted a pilot system test in Tehachapi, California, a city in the Tehachapi Mountains, sited at an elevation of nearly 4,000 feet. During the test, the rail cars were motored up and rolled down a 268-meter (0.16-mile) track.
After the concept was successfully tested, ARES obtained permission to construct the grid energy system in Nevada. The fleet of automated 300-ton electric traction drive shuttle trains is due for completion anytime soon, the news outlet said.
When they are in service, the shuttles will travel up and down a 7.2 percent grade slope and should provide 50 MW of rapid response power to help stabilize the Californian electrical grid supply.
ARES CEO Jim Kelly said that the new system can “be deployed at around half the cost of other available storage technologies. Just as important, ARES produces no emissions, burns no fuel, requires no water, does not use environmentally troublesome materials and sits very lightly on the land.”
This platform is highly scalable, according to the company – with small installations of 100-MW with 200 MWh storage capacity up to large 2-GW to 3-GW systems with 16 GWh to 24 GWh storage capacities.