As the transition of the electricity secotor proceeds, the share of renewable energy in the mix is rising. Their supply curve varies in the course of the day, by weather conditions and seasonally. In order to match varying and relatively inflexible demand and supply, the importance of electricity storage with large capacities increases. Out of the technological options for electricity storage with large capacities, pumped-storage hydropower is the only one with a long history of application and cost-effective operation. Such pumped-storage plants could be built in open-pit lignite mines that are being closed down within the frame of the energy transition. Our first approximative calculation takes the example of the open-pit mines of Hambach, Garzweiler and Inden, located in close proximity to each other in the West of Germany. Combined into one plant, they could reach a storage capacity of up to 400 GWh. This constitutes a factor 10 of total currently installed pumped-storage capacities in Germany and is about the continuous power supply volume of an average nuclear plant for two weeks. In the context of the coal phase-out currently discussed in Germany, this paper presents a concept for energetic follow-up utilisation of open-pit mines after the phase-out that also might provide sustainable employment perspective at least for parts of the staff currently employed in the coal power sector.
Johannes Thema, Martin Thema:
Pumpspeicherkraftwerke in stillgelegten Tagebauen - am Beispiel Hambach-Garzweiler-Inden
(Wuppertal Paper Nr. 194)