Toward the efficient and accurate management of the water-energy nexus: Optimization modeling based on urban resource metabolic mechanism identification

Due to the lack of consideration for the implicit effects of material metabolism within the water-energy nexus, most current studies on the water-energy nexus recognize quantitative water-energy relationships from the standpoint of external intervention. The water-energy nexus metabolic stochastic optimization methodological framework is proposed in this study aims to provide guidance for external macro-management actions by revealing the internal structural and functional characteristics of the system. This framework not only captures the quantitative relationships changes dynamically in water-energy metabolic metabolism by industry, but also integrates the implicit internal action relationships into the industrial optimization model structure, achieving accurate optimization of urban water-energy collaborative management. This methodological framework is tested and validated through a case study of the water-energy system in Tianjin City, China. Multi-dimensional regulation schemes encompassing resource allocation, industrial scale coordination, and pollutant emission adjustments are examined. The results show that within the water-energy nexus, agriculture industry, mining industry, and gas industry are identified as the sectors with the most abundant co-generation and competition between the water and energy systems, which indicates that significant synergies in other industrial sectors will be achieved through the implementation of water-saving, energy-saving, and resource-efficient management measures in these industries in Tianjin. The contradiction between resource-environmental risks and economic benefits in the tertiary industry is prominent and needs further attention. Decision makers should also pay attention to the impact of uncertainty on metabolic mechanisms and resource allocation, as well as understand the positive role of industrial restructuring in promoting the sustainable development of water-energy nexus systems.