When we think of energy storage, we are most likely to think of batteries, or maybe pumped hydro-electric schemes tucked away in the mountains.

But while these are the most successful technologies, in a market that is set to attract $662bn of investment and have a capacity of more than 1,000GW by 2040, they are far from the only methods out there. There are technologies that use compressed air and leverage gravity in various ways to store energy, ranging from ski lifts and mountain railways full of rocks to mine shafts and giant cranes.

One of the more unusual technologies is well on the way to commercialisation. Highview Power, a UK-based company, stores energy by cooling air to -196°C (-320˚F), which turns it to a liquid that can then be stored very efficiently in insulated, low-pressure vessels. The air is liquified when demand, and prices, are low, or when large amounts of renewable power are being generated that cannot be used.

Anywhere there is a lot of wind and solar, there is huge curtailment. That makes the payback of our technology pretty fast

When power is needed, the air is released, turning back to gas and expanding in volume 700 times. This air is used to drive a turbine, creating electricity.

Unlike lithium-ion batteries, which provide power for up to four hours, Highview’s “liquid air” technology operates for between four and 12 hours. That means that in places such as North Africa and Southern Europe, it is possible to have 24/7 solar power, says CEO Javier Cavada. The technology also allows wind farms, which generate much of their energy at night, to store energy for sale at peak times.

In markets such as the UK and Germany, renewable energy producers are often paid not to feed their power into the grid to ensure that it is not overloaded, he points out. “Anywhere there is a lot of wind and solar, there is huge curtailment. That makes the payback of our technology pretty fast.”

Formed 15 years ago, Highview has been painstakingly demonstrating the technology, which the firm dubs a CRYObattery. It opened a demonstration plant in Slough, about 20 miles west of London, in 2015, which ran for four years, while a commercial, grid-scale plant was opened near Manchester in 2018.

Now the company is developing projects to deploy the technology, which has won a number of awards, in the UK and around the world, including the UK’s first commercial liquid air energy storage facility, a 50MW/250MWh facility that will be built at a decommissioned thermal power station near Manchester, which has just been awarded a £10m grant by the UK government.

In addition to storing energy, the plant – which will be one of the largest energy storage systems in Europe – will offer market arbitrage, frequency management, reserve, and grid constraint management services.

The technology has no emissions or water impact and uses benign materials, technology and components

The company is set to expand into Asia as well, after Japanese industrial giant Sumitomo Heavy Industries invested $46m in it. “The Sumitomo investment has opened up markets like Japan, South Korea and Australia,” Cavada says.

“We offer the only long-duration energy storage solution that is commercially available today that offers multiple gigawatt-hours of storage, is scalable with no size limitations or geographical constraints, and produces zero emissions,” he adds. Other advantages include the fact that the technology has no emissions or water impact and uses benign materials, technology and components such as tanks, compressors and turbines, which are proven, plentiful and cheap to buy.

The system works even better if it can harness a source of waste heat or cold to aid with the heating or cooling process, although the majority of the 2GW of projects in Highview’s pipeline are standalone.

“No other technologies can do what we do, except compressed air and pumped hydro,” Cavada says. “But they are both geographically constrained, while ours is an engineered system, which can be deployed relatively easily. We are pumped hydro in a box. And the bigger the facility is, the more effective it is.”

Mike Scott is a former Financial Times journalist who is now a freelance writer specialising in business and sustainability.  He has written for The Guardian, the Daily Telegraph, The Times, Forbes, Fortune and Bloomberg.

This article is part of our in-depth Energy Transition briefing. See also:

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