EWE Gasspeicher GmbH, a wholly owned subsidiary of the Oldenburg-based utility company EWE, plans to build the world’s largest battery by employing the well-known redox flow battery principle in which electrical energy is stored in a liquid along with new, environmentally friendly components in underground salt caverns.

These kinds of caverns are currently used to store natural gas. EWE Gasspeicher is collaborating on the project – brine for power (b4p for short) – with the Friedrich Schiller University in Jena, which developed the innovative components. It uses salt water and recyclable polymers (plastics).

“We need to carry out some more tests and clarify several issues before we can use the storage principle indicated by the University of Jena in underground caverns. However, I expect that we will have an operating cavern battery by about the end of 2023,” says Ralf Riekenberg, head of the brine4power project.

“If everything works, this may fundamentally change the storage market, i.e. the market for control energy. The amount of electricity this kind of storage facility contains – consisting of two medium-sized caverns – is sufficient to supply a major city such as Berlin with electricity for an hour. It means that we will have built the world’s largest battery. In contrast to other energy storage facilities that convert the electrical current into other energy carriers – for example into compressed air – we are storing the electricity directly with brine4power,” says EWE Gasspeicher GmbH Managing Director, Peter Schmidt.