Life cycle sustainability assessment of pumped hydro energy storage

At present, pumped hydro energy storage plays the dominant role in electrical energy storage. However, its development is clearly restricted by the topography and adverse impacts on local residents. Underground pumped hydro energy storage (UPHES) using abandoned mine pits not only can effectively remedy these drawbacks but is also constructive to the management of abandoned mine pits. In this paper, we firstly conduct a comprehensive analysis of conventional pumped hydro energy storage (CPHES) and UPHES, using life cycle sustainability assessment (LCSA). Sustainability indicators in this paper include economic indicators, environmental indicators, and social indicators. Among all the indicators, blue water footprint (BWF) and ecological footprint (EF) are included for the first time to assess the social performance of CPHES and UPHES. Then, this paper employs multi-attribute value theory (MAVT) and scenario analysis to evaluate the overall performance of energy storages. The results show that CPHES has better performance in economy and environment than UPHES because of the economies of scale, while the UPHES has better performance in social sustainability impact because of the absence of stages of excavation and backfilling. When using MAVT methodology, only when the weight for social indicator is three times higher than that of economy and environment; ie, the weight for social dimension is 0.6, and the weights for environmental and social dimension are 0.2; the score of UPHES is higher than CPHES.