RWE launches research into the salty storage of green electricity

The project could see underground caverns store several GWh of electricity from renewable sources

Big Zero Report 2022

RWE Gas Storage West GmbH and CMBlu Energy AG have launched a project aimed to investigate the green electricity storage capabilities of salt caverns.

The partners will research if salt caverns, currently used for gas storage, could be used as large-scale, organic flow batteries with potential storage capacities of up to several GWh of renewable electricity.

To be able to use the salt caverns as batteries in the future, RWE and CMBlu plan to fill them with an organic electrolyte solution, which will serve as the primary energy source – once a suitable electrolyte has been identified, the construction and operation of a test system will start.

The planned generating capacity of that system, which is expected to be finalised by the spring of 2024, is 100KW, with a storage capacity of up to 1,000KWh.

Andreas Frohwein, Technical Managing Director of RWE Gas Storage West, said: “In the future, we may be able to use our salt caverns as batteries for storing enormous quantities of electricity. Using existing technical infrastructure, they could also be connected to the electricity grid quickly.”

Peter Geigle, CEO of CMBlu Energy AG, commented: “Organic flow batteries are based on carbon, which is available globally in almost unlimited volumes. The components are easy to recycle and water is the largest component by volume.

“That means the battery isn’t flammable, so it’s safe to use. In addition, organic storage systems use no metal, unlike most other batteries.”

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