Objective Slope-based gravity energy storage (SGES), an emerging mechanical energy storage technology, can effectively enhance the local consumption of renewable energy, mitigate the intermittency and volatility of wind and solar power. The long-term operational effectiveness of an SGES project is highly dependent on scientific site selection; however, there is currently a lack of systematic methodologies and practical experience in this area.

Method Considering the technical characteristics and application scenarios of SGES, this study proposed a two-stage decision-making framework for site selection, combining geographic suitability analysis with the triangular fuzzy analytic hierarchy process (FAHP). In the first stage, geographic suitability analysis was conducted using an established constraint index system covering critical factors such as elevation difference, slope angle, land use, and infrastructure conditions, thereby identifying candidate sites meeting construction requirements. In the second stage, a multi-criteria decision-making (MCDM) framework comprising nine evaluation criteria across electrical, economic, and social dimensions was developed. The triangular FAHP was employed to determine the criteria weights, and expert evaluations were integrated to comprehensively rank candidate sites. An empirical study was conducted in Guiyang, Guizhou Province, to validate the applicability of the proposed method.

Result The weighting results indicated that electrical criteria, particularly grid reliability, dominate the site-selection decision, whereas social criteria have the lowest weights. Additionally, a 10 kW prototype of the slope-based gravity energy storage system has been successfully constructed at the selected optimal site, further demonstrating the scientific validity and practical utility of the proposed decision-making framework.

Conclusion This research provides theoretical support for the scientific site selection of slope-based gravity energy storage systems and broadens the application of the triangular FAHP in the field of energy storage site selection.