Abandoned Mine Pits and Underground Tunnel-based Pumped Hydro Storage Plants: Preliminary Design and Discussion

This paper presents a preliminary design for abandoned mine pits-underground tunnel-based pumped hydro storage (PHS) system. In the design, the continuous abandoned mining pits along large runoff rivers can be utilized as the PHS upper reservoirs. With the mature shield machine or tunnel boring machine (TBM) tunneling technology, the underground tunnels can be constructed under the mining pits or underground tunnel lines nearby large cities. Correspondingly, the constructed tunnels serve as the lower reservoirs for the PHS plants. On this basis, a preliminary discussion of calculating and evaluating the volume, flow rate and installed capacity of the PHS stations is given. Furthermore, an underground tunnel boring method and its volume estimation approaches are proposed. Additionally, a comprehensive energy supply method of the proposed PHS stations in large river basins is proposed, associated with large-scale photovoltaic (PV) power stations. This approach can solve the grid integration problem of PV supply power in prolonged cloudy and rainy weather. Finally, the challenges and future work to construct the underground tunnel-based PHS stations is preliminary discussed.