A two-stage framework for site selection of underground pumped storage power stations using abandoned coal mines based on multi-criteria decision-making method: An empirical study in China

With the continued transformation of the energy structure, more and more coal mines have been abandoned. The construction of underground pumped storage power stations using abandoned coal mines not only solves the problem of renovating abandoned coal mines, but also ensures a high level of photovoltaic and wind integration. However, the most basic site selection problem of underground pumped storage power plants using waste coal mines has rarely been studied due to the complexity of the technical scheme and the uncertainty of the decision environment. Therefore, a two-stage fuzzy evaluation model is proposed in this paper. Firstly, two sets of site selection index systems are established, namely the veto assessment system and the comprehensive evaluation criteria system. Triangular intuitionistic fuzzy numbers are used for information representation. Then, the veto assessment system is applied for the initial screening of the alternatives. Afterward, the alternatives are evaluated by the comprehensive evaluation criteria system. The entropy method and step-wise weight assessment ratio analysis are utilized to calculate the objective and subjective weights respectively, and the Lagrange optimization method is used to obtain the combined weights. The sorting results of the alternatives are obtained through multi-attributive border approximation area comparison. Finally, an empirical analysis based on eight abandoned coal mines in Datong, Shanxi Province, proves the rationality of the decision-making framework. The weights of natural condition, society, resources, and economy are 29.52%, 23.83%, 28.42% and 18.23% respectively. Natural condition is the most important factor to consider when choosing the site for underground pumped storage power stations. The ranking results of the alternatives is A5 > A2 > A3 > A8 > A7. Therefore, A5 is the optimal location. The results have a guiding role for both governments and investors in the construction of underground pumped storage power stations and transformation of abandoned coal mines.