On 5 July we posted a snippet that caught our eye on sand batteries. This month we give you another novel renewable energy storage technology – liquid air. This sounds like a fantastic idea from Highview Power, a UK company that has the potential to transform the energy storage sector.
Unlike sand batteries, which may be suitable for domestic scale storage, liquid air storage technology starts at around 5 megawatts and can be scaled up to hundreds of megawatts. It uses a cryogenic process to cool cleaned ambient air to minus 196 degrees using the standard hardware for existing liquid natural gas technology. This compresses the volume 700-fold and turns the air to liquid. When heated, the liquid air regasifies with explosive force and is used to drive a turbine. It is pretty much a closed system and as it is only air that has gone in, any exhaust gas that comes out is also air. The primary benefit is that the technology can be used to store surplus energy from wind and solar for long periods of time. At present, wind turbine operators are being paid not to generate electricity when there is insufficient grid capacity to accept it, so the efficiency savings of being able to store that excess energy for later re-use are potentially huge.