Thermal storage power stations represent a highly promising energy storage technology that can be used to balance out fluctuations in the electricity generated by wind turbines and solar power systems and make electricity available when needed. These first convert renewable electricity into high-temperature heat and store it in this form. A range of substances can be used as the storage material for high-temperature heat, including molten salts and various kinds of solids, which are the best-known options. To extract the energy from storage again when renewable electricity is in short supply, high-temperature heat is used to generate steam, which drives a turbine. This is how the thermal storage power station makes the previously stored renewable electricity available when it’s needed.
The StoreToPower project
In the StoreToPower project, project partners Deutsches Luft- und Raumfahrtzentrum (DLR), RWE Power and Aachen University of Applied Sciences investigated the feasibility of a thermal storage power station in the Rhenish region as a retrofit to an existing lignite-fired unit. The study also considered a pilot plant to develop this technology, which would involve retrofitting a high-temperature thermal storage module to a large lignite-fired power station unit. The feasibility studies show, however, that from the perspective of RWE Power, it is unlikely that this will be a cost-effective prospect for the company’s power station locations in the Rhenish region using the technology in place there. Following the conclusion of the feasibility studies in 2021, therefore, the project is not being pursued further.