Multi-Scenario Simulation of a Water–Energy Coupling System Based on System Dynamics: A Case Study of Ningbo City

Abstract

In this work, based on the concept of collaborative water–energy development, a multi-scenario system dynamics simulation model of a water–energy coupling system was constructed by using the system dynamics modeling method. The model was composed of four subsystems: society, economic, water resources, and energy. Taking Ningbo City as the research location to run the simulation model, the analysis of the validity of the model showed that the relative error between the historical data and the simulation results of the model was less than 10%, which proved that the model passed the test. In this paper, based on the scenario of business an usual (BAU), three scenarios of water-saving scenario (WSS), energy-saving scenario (ESS), and comprehensive savings (CS, the comprehensive scenario considers water-saving and energy-saving together) were designed, and the simulation indexes in the three scenarios were refined in order to strengthen the control of water-saving policies, improve the effective use of water, optimize the industrial energy structure, improve the level of energy-saving-related technologies, and advance the urbanization process. The simulation results for Ningbo City from 2010 to 2030 show that the water–energy coupling system is affected by many factors, and the adjustment of a driving factor of any subsystem will have an impact on the water–energy coupling system. There are two driving factors: the first is a constant variable related to water resources, energy, society, and economic, and the second is a variable affected by time. The coupling system is based on the law of real development and is composed of causal and functional relationships between variables. Therefore, within the prediction range of 2030, the driving factors in the coupling system are controllable, and there is no uncontrollable situation. The strengthening of water-saving policies and the improvement of the coefficient of the effective utilization of water will have the optimal saving effects on water resources and energy at both the single and the coupling level; this also demonstrates that the water resource management in Ningbo City plays an extremely important role in the relationship of the water–energy coupling. The results of this study are expected to provide a valuable reference for the management and conservation of water–energy coupling in Ningbo City.

Eco-Efficiency Assessment of Beijing-Tianjin-Hebei Urban Agglomeration Based on Emergy Analysis and Two-Layer System Dynamics

“…The results show that there is a certain difference in the fitting degree between the simulation data and the statistical data, which is directly related to the accuracy of historical data and the logical structure of the model itself. The relevant literature indicates that when the system dynamics model is used for trend prediction, the error is acceptable within 30% [42]. Therefore, effectiveness analysis in Table 3 shows that the model can accurately describe the high-quality development status of the Beijing-Tianjin-Hebei region and has a good prediction function.…”

Pathways for the carbon peak of resource-based cities under an energy-water coupling relationship: A case study of Taiyuan, Shanxi Province

“…Based on the close dependence between the system behavior and the internal mechanism, it is obtained through the process of establishing and operating the mathematical model, and gradually discover the cause and effect relationship that produces the change form. Modeling with computer software Vensim, the thinking process and research on complex problems can be displayed, which is suitable for analyzing and solving a series of non-linear, complex system problems (Yin et al, 2021). This paper selects the geospatial boundary of Taiyuan city, Shanxi Province, as the research system boundary.…”

“…A coupled system is not a simple sum of independent subsystems. Building coupled systems using SD models Frontiers in Environmental Science frontiersin.org requires solving the following two problems: first, two independent subsystems must become an integrated system through one or more bridges or mediums (Yin et al, 2021). In this study, water resource carbon emissions and energy carbon emissions are related through total water consumption, total energy consumption, water-related energy consumption and energy-related water consumption.…”

“…In this study, water resource carbon emissions and energy carbon emissions are related through total water consumption, total energy consumption, water-related energy consumption and energy-related water consumption. Second, the coupling system may produce overlapping effects, resulting in total carbon emissions greater than the actual value (Yin et al, 2021). To eliminate the overlapping effect, this paper divides total energy consumption into water-related energy consumption introduced by the social water cycle and other types of energy consumption other than water-related energy consumption.…”

“…The simulation errors of the model were verified by comparing the relative errors of the historical data and the simulation results. According to the following formula (Yin et al, 2021), the relative errors of the simulated values of nine variables from 2005 to 2020 were calculated. As shown in Supplementary Table S2, among the 9 variables, the relative errors of production water in 2018 are large (3.32%); the relative errors of total water consumption in 2013 and 2018 are 1.66% and 1.9%; and the relative errors in S2, the relative errors of the predicted data are approximately 2%, indicating that the model has high accuracy.…”