German utility plans 30 MWh zinc-bromine BESS
German utility Stadtwerke Gaggenau and Capac AG will build a 7.5 MW/30 MWh zinc-bromide BESS in Gaggenau, set for commissioning in 2028, with a €15.2 million investment.
Stadtwerke Gaggenau, the municipal utility serving the southwest German town of Gaggenau, and Capac AG, a German energy infrastructure company, have announced plans to construct a 7.5 MW/30 MWh battery energy storage system (BESS) using zinc-bromide technology. The project will be located on the site of the utility’s former liquefied gas plant, with construction scheduled to begin next year. Capac AG will serve as the general contractor, overseeing technical planning, procurement, system integration, and commissioning, which is planned for 2028.
The BESS will utilize zinc-bromide technology, selected for its non-flammable, water-based electrolyte, long expected operating life, and low projected capacity degradation. According to Benjamin Henecka, CEO of Capac Energy, the technology is designed for a 25-year operating life with capacity degradation of approximately 3.6% over that period. Henecka emphasized the safety advantages, noting the absence of thermal runaway and the non-flammable nature of the electrolyte as critical factors for utilities prioritizing long-term infrastructure investments.
The project is jointly funded by Stadtwerke Gaggenau and JP Holding, the parent company of Capac, with a total investment of €15.2 million ($16.8 million). Henecka highlighted that the economic evaluation focuses on lifecycle value rather than initial purchase price, considering factors such as capacity degradation, maintenance, auxiliary consumption, and financing costs over the full investment period. Revenue is expected to come from arbitrage trading in day-ahead and intraday markets, as well as ancillary services.
The BESS will be built using battery systems supplied by US manufacturer Eos, featuring the Intensity architecture with modular units arranged in a compact, engineered steel support structure. The zinc-based batteries use materials including zinc bromide, conductive plastic, and graphite felt. Henecka noted that the non-flammable aqueous chemistry enables a different fire-risk profile compared to conventional lithium-ion systems, while also reducing exposure to Chinese-dominated lithium-ion supply chains.