Optimizing urban water supply from water-energy nexus perspective: A case study of Beijing

Abstract:

Water and energy resources are inextricably interrelated in the production and consumption processes, namely water-energy nexus (WEN). The importance of WEN in securing water and energy for sustainable urban development has been globally acknowledged, and great attentions have been paid to decoupling and modeling the urban WEN black box. Comparatively, endeavors about shifting nexus from concept to governance practice are relatively rare. In this paper, Water Evaluation And Planning System (WEAP) is employed to build the WEAP_Beijing model (2003-2017) for empirical study, with energy intensity input as the water supply cost to optimize the water supply structure of Beijing. Results show that the carrying capacity of water resource in Beijing is improved. While the total energy consumption in water supply system is incremental from 2.82 Billion kWh in 2003 to 4.94 Billion kWh in 2017, driven by the increasing ratio of South-to-North transferred water (SNTW) and recycled water, 22% and 27% in 2017 respectively. The water supply ratios to meet the water demands have been quantified based on the WEAP_Beijing model, which is the basis to construct and analyze the water supply network in Beijing. For example, the domestic water demand is satisfied by surface water, groundwater and SNTW, with a ratio of 18.86%, 44%, and 37.14% respectively in 2017. Next, scenario analysis will be conducted to explore energy friendly water supply and provide reliable information for decision-making. In the end, this study will complement the WEN governance, with implications to advance the sustainability of water and energy in urban systems.