There's a new thing approximating a battery supplying power to the grid in Manchester today, as the latest development in energy storage technology goes live. This one's air-based, using liquefaction to store gas in a liquid form for later use.
It works by chilling air to -196C, turning it into a liquid at times of peak renewable energy generation. This liquid is then stored until there's additional demand from the grid, when it's warmed and rapidly expands back into a gas at 700 times its chilled volume again in a process they call "rapid re-gasification," turning the expansion turbines that generate electricity and outputting nothing more than... air.
The main advantage to this system is the length of time the cooled air can stay in place, or charged and ready for use, with developer Highland Power saying it can all be built with off-the-shelf components, so no need to pay through the nose for precious imported lithium. And there's no degradation of capacity over time, as with traditional chemical mega-battery systems.
The current test site operates at a modest 5 megawatts maximum capacity, although Highland says it could scale up to hundreds of megawatts if the right clean energy subsidies were made available. [Highland Power via Guardian]