Four years ago, I wrote about a new start-up energy storage technology company that had partnered with GE. This week, that company, Highview Power, has opened the world’s first grid-scale liquid air energy storage (LAES) plant, offering an intriguing and promising alternative to battery storage.
Liquid air energy storage is an exotic-sounding but relatively simple technology process that involves using off-peak or renewable electricity to cool air to -196°C (-320˚F), at which point it turns into a liquid that can then be stored efficiently in insulated, low-pressure vessels. When the liquid air is released, it turns back into a gas and rapidly expands in volume, driving a turbine to generate electricity.
The technology has the potential to provide longer-duration energy storage than batteries can offer – the pilot plant, at a landfill gas site in Bury, north-west England, a 5MW/15MWh facility, will be able to power 5,000 homes for around three hours and will demonstrate how the technology can provide reserve, grid balancing and regulation services. But Highview says LAES can easily be scaled up to hundreds of megawatts, in line with the energy demands of entire towns and cities. “This means that LAES plants could easily store enough clean electricity generated by a local windfarm to power a town like Bury (around 100,000 homes) for many days, not just a few hours,” the company says.
It hopes that the opening of the much-delayed plant will pave the way for the technology to be adopted around the world. “ True long-duration energy storage is critical to enable the broader deployment of renewable energy; overcome the intermittency of solar and wind energy; help smooth peaks and troughs in demand; and provide a stable and secure source of homegrown energy, ” it says.
Liquid Air has a number of advantages over batteries – it is made mainly from straightforward steel components and an industrial air liquefier. It does not require hard-to-access, exotic or harmful materials such as cobalt and there is no pollution. And because the plant is based on simple, well-understood and widely available technology, the components are cheap. It looks like an old-fashioned piece of industrial equipment rather than a futuristic, state-of-the-art piece of high-tech kit. That means it is more robust and long-lasting – the plant is expected to 30-40 years, rather than the 10-year life span of batteries. And at the end of its life, it can simply be recycled.
In some ways, the technology is similar to other energy storage technologies such as compressed air stored in underground caverns or pumped hydro-electric. But it has the advantage that it doesn’t need a cavern or a dam – it can be sited wherever it is needed and can be deployed at the appropriate scale. The pilot plant will take waste heat created by the site’s landfill gas engines and convert that to electricity, boosting the system’s efficiency and demonstrating how the technology could be deployed at industrial facilities. It can also use waste cold to help with the liquification process if it is available.
“The adoption of LAES technology is now under way, and discussions are progressing with utilities around the world who see the opportunity for LAES to support the transition to a low-carbon world,” Gareth Brett, CEO at Highview Power, said. “The market opportunity for LAES technology is exciting – we estimate that 60% of the global energy storage market comprises long-duration, grid-connected storage and that our LAES technology is ready to meet almost half of this (45%). We are already in detailed negotiations to build plants ten times the size of this one for utility customers of several nationalities and for various different applications.”