An interdisciplinary feasibility study on hybrid pumped hydropower storage of excess energy in open-pit coal mines

Abstract

Scheduled decommissioning of lignite mining in Europe requires innovative and economic strategies to support coal regions in transition. The R&D project ATLANTIS is funded by the European Research Fund for Coal and Steel and started in late 2021, aiming at an integrated feasibility assessment on transforming open-pit coal mines into hybrid energy storage projects. Hereby, repurposing of open-pit mines for hybrid pumped hydropower storage (HPHS) of excess energy from the electric grid and renewable sources available in the vicinity of open-pit mines in abandonment will contribute to the EU Green Deal, while increasing the economic value, stabilising the regional job market and contributing to EU energy supply security. The main objective of ATLANTIS is the elaboration of a technical and economic feasibility study on HPHS in open-pit coal mines. The present contribution will provide insights into the R&D activities within the scope of the project. For that purpose, two target open-pit mines in Greece and Poland were investigated in detail, including analyses supported by geographic information systems (GIS) based on previously defined HPHS design criteria [1] as well as hydro(geo)logical, hydrochemical and geotechnical analyses. At the Polish Szczercow mine located in the Lodz Coal Basin a HPHS capacity of 350 MW can be realised with a hydraulic head difference of approximately 240 m, able to support even more than the currently planned build-out of about 250 MW renewable energy sources made up of wind and photovoltaic parks. A total capacity of 180 MW is feasible at the Kardia mine in the Ptolemais Basin in Greece, whereby the hydraulic head difference amounts to about 100 m. Here, a photovoltaic build-out of 1.2 GW is scheduled. Potential environmental impacts were addressed via an extended risk analysis, consisting of qualitative and quantitative and components integrated by means of feedback loops and supported by the experience of multidisciplinary experts in the fields of hydrogeology, hydrogeochemistry, geotechnics, mining engineering and socio-economics. Based on the findings of this assessment, mitigation measures for the high-ranked risks were defined and are already considered in the course of the specific mine abandonment processes. Dynamic economic models using day-ahead energy market data were implemented to optimise the HPHS operation and support decision making related to the operational modes. Furthermore, the results of the socio-economic footprint assessment undertaken highlight the regional benefits of the HPHS implementation as alternative to the previously envisaged restoration procedure. The elaborated feasibility study on HPHS in abandoned open-pit mines is a key contribution to the industrial partner’s decision making processes and further demonstrates the potentials for application of the project’s findings at the EU level.   [1] Krassakis, P., Karavias, A., Zygouri, E., Roumpos, C., Louloudis, G., Pyrgaki, K., Koukouzas, N., Kempka, T., Karapanos, D. (2023): GIS-Based Assessment of Hybrid Pumped Hydro Storage as a Potential Solution for the Clean Energy Transition: The Case of the Kardia Lignite Mine, Western Greece. Sensors, 23, 2, 593. https://doi.org/10.3390/s23020593   The present study has received funding from the Research Fund for Coal and Steel—2020, under grant agreement No. 101034022 (ATLANTIS).