Energy storage is hot topic because more and more electricity is being generated from renewable sources like solar power and wind power that can’t operate all the time because the sun doesn’t always shine and the wind doesn’t always blow. So we need ways to store surplus energy when it is produced and be able to use it later when it is needed.
There are many ways to store energy including batteries, compressed air, molten salt, and others. Historically and right on up to today, the most established energy storage technique is pumped hydro storage which uses electricity to pump water from a low elevation reservoir up to a higher elevation reservoir; when power is needed, the water is released downhill and runs turbines to generate power. It works great, but it is only practical in the small number of places where the local geography permits.
A Santa Barbara company called ARES, which stands for Advanced Rail Energy Storage, is pioneering a new technique which, like pumped hydro, uses gravity to store energy.
The way it works is when there is surplus electricity, electric motors drag 9,600 tons of rock and concrete-filled automated railcars up a 2000-foot hill. When power is needed, the rail cars coast down the hill and generate electricity using the same regenerative braking systems found in hybrid cars. It is pretty simple and can work in many places.
The first ARES system is being built in Pahrump, Nevada and will provide 50 megawatts of power to the local grid. How economical the technology can ultimately be remains to be seen but it is an interesting new approach to solving the energy storage problem.
Photo courtesy of AmusingPlanet.