So-called “organic redox-flow batteries” could be a sustainable, cost-effective and highly efficient alternative to lithium-based energy storage solutions. In Essen, western Germany, a joint project is underway to investigate how subterranean salt caverns could be used to store potentially several gigawatt hours of electricity from renewable sources. For comparison, Europe’s largest (lithium-ion) battery located in Jardelund, Schleswig-Holstein, has a maximum capacity of just 50 megawatt hours.
RWE Gas Storage West GmbH currently uses the caves for gas storage but are investigating how they could be turned into batteries with the help of CMBlu Energy AG, a company which specialises in electrolyte-based storage solutions. The salt caverns would be filled with an organic electrolyte solution which would serve as the primary energy source.
Several potential electrolytes have been identified for the purpose and will be tested for suitability over the next few months. Construction of a pilot storage system with capacity of 1,000 kilowatt hours is planned to start in spring 2021.
Andreas Frohwein, technical managing director of RWE Gas Storage West, is convinced of the electrolyte batteries’ potential: “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,” he says in a .
Peter Geigle, CEO of CMBlu Energy AG, explains why he thinks the future of storage is organic: “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.”