Project "RedoxWind"

Energy storage devices are becoming increasingly important as a result of the German energy transition. They can compensate for natural fluctuations in solar and wind energy, and thus convert a renewable energy source into a predictable generating station with uninterrupted supply. They can also make a decisive contribution to grid stability and frequency control, and reduce the need to extend the grid.

In the framework of the RedoxWind project, a large-scale redox-flow battery storage device will be developed and connected directly to the intermediate DC circuit of a wind turbine. This unit, consisting of a generator and a battery storage device, will be constructed as a pilot unit at Fraunhofer ICT in Pfinztal.

One focus of research will be the adjustment of the wind power plant to the battery operation, and also in particular the scaling up of the redox-flow technology from the laboratory scale through to stacks with a power of several kilowatts, which can be manufactured on an industrial scale. Particular emphasis will also be placed on the use of synergies between the wind power unit and the battery. The redox-flow battery storage device is connected directly to the intermediate DC circuit of the wind power unit. Compared to a grid connection, this direct connection eliminates the need for an additional conversion step in power transfer, and reduces the investment costs needed for the conversion technology.


This type of connection between the wind power plant and the battery could ensure self-sufficient electricity supply to isolated applications, companies or energy-efficient villages.

Project data

  • Redox-flow battery with a final stage of 2 MW power and 20 MWh capacity
  • Wind turbine with 2 MW power, 100 m hub height and 82 m rotor diameter
  • Generator-storage unit consisting of a large-scale battery connected to the intermediate DC circuit of the wind power plant


RedoxWind is a publicly-funded project, with an equal contribution from the State of Baden-Württemberg and the German Federal Ministry of Education and Research (BMBF).