Multiregional input-output analysis for energy-water nexus: A case study of Pearl River Delta urban agglomeration

The energy-water nexus (EWN) is an important concept for advancing sustainability issues, especially in urban agglomerations with complex interactions between energy and materials. Based on the deficient analysis method of EWN assessment at urban agglomeration scales, we proposed an intercity method for compiling an urban agglomeration multiregional input-output table for exploring the nexus in urban agglomerations. After combining location quotients and a gravity model, a multiregional input-output table of an urban agglomeration was built based on provincial input-output tables. The detailed consumptions by water-related energy and energy-related water were then systematically calculated to investigate the EWN. A case study was conducted to demonstrate the scenario of coupled energy and water in 2015 for the Pearl River Delta urban agglomeration. The results showed that manufacturing plays an important role in both energy and water consumption, while agriculture consumed the largest amount of water, and transport consumed the largest hybrid energy in developed cities. Although with relatively high resource utilization efficiencies, the more developed cities in the urban agglomeration (e.g. Shenzhen, Guangzhou, and Foshan) still consumed large amounts of energy and water, implying the relatively great magnitude of resource consumption driven by the developed economies. On the whole, energy consumption increased from southwest to northeast, while the water consumption increased from southeast to northwest. It was found that Shenzhen depended mostly on other cities in the urban agglomeration for both energy and water, and that Huizhou was the most self-sufficient city. Based on the characteristics of the EWN in the Pearl River Delta urban agglomeration, it is suggested that local managers should improve vehicle fuel efficiencies, reduce water consumption rates for agriculture, save water for energy production, and optimize the structure of manufacturing. In addition to these findings, this work sets a baseline for EWN studies in urban agglomerations.