RWE is constructing a 400MW battery storage system on a former industrial site in Lingen, Lower Saxony.
The facility will provide at least 800MWh of capacity and will go into operation in 2028, according to the company.
RWE added that the installation will help stabilise the electricity grid by supplying balancing energy and new services such as instantaneous reserve.
The project is being developed on the former Dralon GmbH premises northeast of the Emsland gas-fired power plant.
Nikolaus Valerius, chief executive of RWE Generation SE, said: “With the expansion of renewable energies, the demand for firm capacity is growing.”
He added: “Our new battery storage facility in Lingen will absorb or feed in power within a few milliseconds, depending on demand.”
More than 200 lithium-ion battery units will be deployed alongside over 100 inverters, more than 50 medium-voltage transformers, two high-voltage transformers and two switch panels.
The site will connect to the electricity grid via the Hilgenberg substation, which Amprion is building less than 50 metres away.
Preparatory works start on 2 February following receipt of all necessary permits for the 8.5-hectare area.