Assessing the Safe Development Potential of Gravity Energy Storage in Mining Goafs by Coupling Time-Series InSAR and GIS: A Case Study of Yangquan, China

Assessing the development potential of gravity energy storage (GES) in mining goafs is vital for the integrating new energy power generation, achieving carbon neutrality goals, and transforming resource-based mining cities. This study proposes an integrated evaluation system using time-series interferometric synthetic aperture radar (InSAR) and a geographic information system (GIS) to assess the safe development potential of GES in goafs. First, a goaf subsidence risk model is constructed based on time-series InSAR. Subsequently, a GES development suitability model is established by integrating environmental parameters including topography and geomorphology. Finally, the GES development potential of goafs is quantitatively evaluated based on energy storage capacity and the Levelized Cost of Gravity Storage (LCOGS). A case study in Yangquan demonstrates that, based on SBAS-InSAR monitoring results from 2021 to 2022, seven out of eight closed mining areas covering a total area of 53.91 km2 are suitable for the development of GES facilities. Under defined scenarios, the Nanzhuang Mining Area demonstrates particularly strong potential, with a projected energy storage scale of 410 MWh and an LCOGS of 0.5894 CNY/kWh, indicating good GES development potential. The proposed safety-constrained workflow provides a robust tool to guide GES development in goafs and is transferable to other resource-based and post-mining cities worldwide.