Israeli company Augwind Energy is planning to build the world’s first commercial-scale “air battery” in Germany, using underground salt caverns to store compressed air for electricity generation
The salt-air battery, which can run for more than 20 years, offers a sustainable alternative to lithium-ion. Unlike lithium, which is costly and environmentally damaging to mine, salt and air are abundant, cheap and safe.
These batteries work by converting oxygen and saltwater into stored energy, with remarkable durability. They don’t degrade like lithium cells, meaning they can last decades without replacement. If scaled, this could end reliance on rare earth metals
This innovation could transform energy storage for solar and wind farms, allowing entire cities to rely on clean energy 24/7. The salt-air battery offers a blueprint for a circular and sustainable energy economy.
Air-based systems, like those developed by Augwind, compress air and store it, often in underground salt caverns, for later use in power generation. These technologies aim to provide long-duration, large-scale energy storage to support the transition to renewable energy sources.
Scheduled to start in 2027-28, the facility will be the first operational installation at scale of Augwind’s ‘AirBattery’ hydraulic compressed air energy storage (CAES) system designed specifically for grid-scale energy storage for months at a time.
Germany has over 400 caverns suitable for AirBattery, and geological potential for storing 330 TWh in total. AirBattery is said to be highly cost-effective at US$10-15 per kWh, and environmentally friendly, with almost no hardware degradation over a 40 year lifetime.
In addition, it uses locally sourced materials as opposed to the critical and non-local minerals needed for lithium-ion batteries
The AirBattery system combines two well-established technologies: it merges pumped hydroelectric principles with compressed air storage, circulating water between underground chambers to compress and decompress air at vast scales.
Excess energy is used to compress air to pressures from 50 bar all the way to above 200 bar, depending on the demand and geomorphic structure of the cavern, and feed the pressurised air into the vast underground network.
See also: As countries ramp up the percentage of renewables in their energy mix, molten salt energy storage offers the potential to take the energy transition to a new level with dispatchable renewable power generation at any time
