1 8 Figure 2 – Principles of operation of a conveyor belt-based energy storage system (CB-GES) CB-GES leverages the existing steep topography and the availability of bulk granular materials (such as sand, gravel, and crushed rock) from former open-pit mines. Its storage capacity is limited only by the size and geometry of the stockpiles and the elevation difference between them. The main parameters that affect the performance of the CB-GES are the height difference between the upper and lower stockpiles, the conveyor belt inclination, the type of conveyed material, the loading factor, the frictional and rolling resistances, and the motor/generator efficiency. 3. EVALUATION AND SELECTION METHODOLOGY OF POTENTIAL LOCATIONS FOR GES 3.1 Factors influencing the applicability of this technology in post-mining areas Geotechnical factors. The identified and selected slopes should be evaluated for stability. Slope stability should be analysed in two dimensions (2D) and/or three dimensions (3D) utilising numerical methods [15]. To perform numerical computations in 2D and 3D, it is necessary to determine the basic geotechnical parameters for each identified geological layer. These parameters should be determined somewhat differently for rock formations and for soil deposits. However, for each layer, it is essential to determine the unit weight, cohesion, angle of internal friction, Young’s modulus, and Poisson’s ratio. If necessary, residual parameters should also be specified. Shear Strength Reductions Technique (SSR) should be applied for that purpose. The stability of selected slopes should be analysed in the “natural” state (without a gravitational energy storage system) and under the additional load from a gravitational energy storage system.
RkJQdWJsaXNoZXIy MTM0Mzk2