All aboard! Energy storage goes on the rails
http://www.energysavingtrust.org.uk/blog/all-aboard-energy-storage-goes-rails08/07/2016
Track, rail car, concrete slabs. Not the first three things you might consider as essentials in the field of energy storage. But out in the open spaces of the United States, there's a rail/energy revolution happening, relying on some of the oldest principles going.
Advanced Rail Energy Storage, or ARES for short, is basically all about trains carrying concrete going up and down a track, gravity, and the application of potential energy.
When you've generated excess electricity – for example through renewables such as wind or solar – a rail car bearing weight goes up an inclined track, using that electricity in a motor. When you want that electricity back, it coasts back down the incline, turning the motor in reverse.
Sure, there's a little more infrastructure and land involved than a battery, but the technology claims an 86 per cent (and rising) efficiency in conversion, and could pack anything anything from 20MW to a mighty 3GW of punch – essentially a power plant on rails.
