If you say energy storage today, most people think you are talking about batteries. The intermittency of renewable energy sources such as solar and wind means sometimes there is more electricity available than is needed. Batteries can take that excess electricity and store it until such time as it can be put to work. But there are other ways of storing electricity that rely on potential energy.
An example of potential energy is a freight train parked at the top of a mountain. If there are generators connected to its wheels, they can create electricity as the train rolls downhill. When there is excess electricity available, it can push that same train back up the mountain.
Some energy storage systems are long duration and some are not. A train sitting on top of a mountain could store all that potential energy for weeks, months, or even years. A battery often loses some of its…
Energy Storage Is Going Underground
