Saving energy with liquid air

A pioneering project by Highview Power will turn air into liquid for energy storage to help electricity grids cope with a growing amount of wind and solar power.  

The world’s first full-scale “liquid air” plant, located in northwest England, is based on a technology that advocates say is cheaper and able to provide power for longer periods than lithium-ion batteries. The energy plant uses excess or off-peak electricity to chill air to -196C, transforming it to a liquid state to be stored inside large metal tanks. Pumping and heating is used later to turn it back to a gas, which is released to turn a turbine, generating electricity at times of need—but without burning the gas and releasing emissions.  

While relatively small at 5 megawatts (MW), compared to 50MW lithium-ion battery facilities, Highview Power said the technology could be scaled up to hundreds of megawatts.  

Gareth Brett, the company’s chief executive, said the technology could timeshift energy across the day, with the firm buying electricity when cheap and releasing it when prices are higher. “If you only want to store energy for an hour, lithium-ion is fine, but the reality is that people are looking to store excess renewable power and release it at peak times, which is usually four hours or more,” he said.