A 100 m tall wind turbine is being erected at the German Fraunhofer Institute for Chemical Technology (ICT) test facility. Once construction is completed the testing of one of Germany’s largest batteries can begin.

Under the header of RedoxWind project, ICT has been developing a large-scale redox-flow battery. The aim is to use the battery to store wind energy. The 2 MW power and 20 MWh capacity battery can supply the power needs of a village for up to ten hours. An industrial hall at the test facility in Pfinztal, Baden-Württemberg houses 45,000 liter tanks to store electrical energy in liquid electrolytes.

The tanks have been waiting patiently for the arrival of the custom-build wind turbine. The ICT scientists, however, are less patient. They have been planning the project for years. Now, finally, large trucks have been arriving at the facility to deliver the components of the 2 MW wind turbine. Once the turbine with its 82 m rotor diameter has been erected, they can finally get their hands on the real thing.

Industrial scale
Energy storage is the missing link in the transition to renewable energy. It is the necessary component to integrate intermittent sources like wind and solar into the grid at a large scale. With the RedoxWind project, ICT is building a generator-storage unit that can contribute to balancing power generation and demand, or function as a stand-alone device in remote areas.

The goal of RedoxWind project is twofold: to scale-up redox-flow battery technology so that it can be manufactured at an industrial scale. And, secondly, to tweak the wind turbine to find the optimal mode of operation for the battery. The battery will be connected directly to the intermediate DC circuit of the turbine. 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.

Image by Ad-liftra. CC BY-SA 3.0 licence.