The success of the energy transition from fossil fuels to renewable energies depends significantly on storage capacities. The decommissioning of coal-fired power plants in Germany over the next ten years will lead to a supply deficit of 30 to 40 GW at night without wind power. On sunny days, however, a surplus of photovoltaic electricity of over 50 GW is already expected and will continue to be expected in the near future. The traditional technology for storing large amounts of electricity is pumped storage. This robust technology has a service life of approximately 100 years, compared to batteries with approximately 20 years. However, there are very few available and approved sites for new pumped storage power plants in Germany. Therefore, alternative locations must be found.
This article describes a new approach that proposes using existing, old open-cast lignite mines as sites for new pumped storage power plants. In the Renish mining district – a region between Cologne, Erkelenz, and Aachen – three large open-cast lignite mines are currently in operation, but these will be decommissioned in the coming years. The open-cast lignite mines reach depths of between 200 and 400 meters, thus offering ideal conditions for pumped-storage power plants. The Hambach mine, in particular, with its 400-meter depth, is exceptionally well-suited for such an unconventional pumped-storage power plant. A key feature is the separation of the water volume between the upper and lower storage basins from the residual water in the retention basins. The lower storage basin can be constructed in large, reinforced concrete caverns with a diameter of over 60 meters. The upper storage basin is located near the former ground level. The Hambach site allows for the installation of a capacity exceeding 6 GW and a storage capacity of over 50 GWh, which would surpass the maximum output of the largest pumped-storage power plant in Germany by at least five times. This Hambach pumped-storage power plant could cover a large portion of Germany’s total storage demand during the day-night cycle.
Citation: Risse, H. & Schmidt-Böcking, H. (2025). Pumped Hydro Power Plants in Lignite Coal Mining Pits as a Chance to Supply Big Electrical Power Rates. Adv Earth & Env Sci; 6(4):1-5.
DOI : https://doi.org/10.47485/2766-2624.1084