Energy and water are intertwined in the urban water cycle and need to be coordinated for an integrated resource utilization and more resilient structure. This paper presented a multi-objective optimization model for the energy-water nexus in urban water cycle targeting less energy consumption and more water sustainability with a case study of Beijing. The findings show that the total energy consumption of the social water cycle is 389.831 billion kWh, the maximum of energy consumption in water use processes is water use process. The least energy consumption is the water supply process. Based on the ecological network analysis method, a social water cycle network with 19 flow paths of 7 nodes is constructed. Based on the non-dominated sorting genetic algorithm II (NSGA-II), a multi-objective optimization of energy-water nexus in the urban water cycle was performed to achieve the coordinated goal of water sustainability and energy consumption. The findings may help promote the urban water system management and improve its sustainability.
Keywords water cycle system, energy-water nexus, multi-objective optimization, ecological network analysis, energy consumption