Pioneering test for the world’s largest battery successful

EWE GASSPEICHER: Politicians must provide legal certainty for electricity storage facilities

Berlin, Germany, 22 November 2017. “It is still too early to speak of a breakthrough. We have, however, reached an important milestone in the development of a salt water battery, since one of the key components has met all of the requirements in current tests,” said Peter Schmidt, Managing Director of EWE GASSPEICHER GmbH, speaking to journalists on Wednesday in Berlin.

EWE GASSPEICHER GmbH, a wholly owned subsidiary of the Oldenburg based utility company EWE, plans to build the world’s largest battery in the
brine4power project. The battery makes use of the well-known redox flow battery principle, in which electrical energy is stored in a liquid, along with new
sustainable components in underground salt caverns. EWE GASSPEICHER currently operates 38 such caverns in Germany and uses these for storing
natural gas.

A key component of the new redox flow application is organic polymers (plastics), explained Prof. Ulrich S. Schubert of the Center for Energy and Environmental Chemistry Jena (CEEC Jena) at the University of Jena. They are dissolved in saturated salt water, also known as brine. This creates an electrolyte, i.e. a liquid that can attract or release electrons. “The polymers to be developed had to meet very specific chemical requirements. Among other things, they must be readily soluble in saturated salt water, ensure a certain flow property of the brine-polymer mixture and be chemically and electrochemically stable in their dissolved state in order to be able to attract and release electrons in the long term. These special requirements have been met by the polymers being further developed by the Friedrich Schiller University in the basic preliminary tests that have now been carried out using the original brine formula from EWE,” Schubert explained. “This means that we have taken a big step closer to achieving our goal of building the largest battery in the world,” said Ralf Riekenberg, head of the brine4power project at EWE GASSPEICHER GmbH. Despite this success, many issues still need to be clarified before the storage principle demonstrated
by the University of Jena in underground caverns can be used. “However, I continue to expect that we will have an operating cavern battery by about the end of 2023,” said the EWE expert.

Policies are needed

Technology that works is, however, only one of the prerequisites for the project to succeed. “New policies are also needed here,” said Riekenberg, adding, “Under energy laws, only natural gas storage facilities have been defined as storage facilities. A definition and thus a legal framework for energy/electricity storage facilities commensurate with their role are currently missing. This lack of categorisation of energy storage facilities within the energy industry means that they are currently classified as energy end-users, and therefore operators are generally required to pay all end-user fees such as the network fee, the German Renewable Energy Act (Erneuerbare-Energien-Gesetz – EEG) levy and electricity tax.”
According to Riekenberg, this means that an electricity storage facility, such as the one planned by EWE GASSPEICHER GmbH, stores excess electricity that would not have even been produced without the storage facility because the wind turbines that could produce it would otherwise be switched off due to a network overload. Nevertheless, the storage facility operator is generally required by law to pay the aforementioned end-user fees, in addition to the actual electricity price. “Although this problem has already been recognised by politicians to some extent, the exceptions for electricity storage facilities introduced in this regard do not yet provide a stable and legally secure framework for storage operators.
It is up to the policymakers to change this,” said Ralf Riekenberg. This could result in electricity storage facilities becoming an important option for flexibility and contributing to balancing generation. “brine4power could then become the missing piece of the puzzle in a German energy turnaround.” “In addition to these legal conditions, it also directly affects the technology itself. At the same time, the further research and development of polymer redox flow battery technology in Germany must be intensively supported. Only then can end-to-end battery production in Germany be established again, including the associated closed value chain and the creation of many jobs,” Schubert added. “Particularly if coal-fired power plants are soon to be decommissioned, there is a need to create ‘green’ alternatives capable of satisfying the base load. The polymer redox flow battery would be perfect for