System Dynamics Modeling of Water–Energy Nexus for Resource-Saving Policy Assessment

Abstract

One of the key issues in managing water and energy systems is to incorporate the links between these systems to ensure security of resources. In this research, using system dynamics (SD) approach for simulating water–energy (WE) nexus, SD-WE model was developed for 16 sub-basins of Gavkhuni basin in central Iran. Various water- and energy-saving policies were simulated and their effectiveness in improving resource security was evaluated using water- (WSI) and energy-saving (ESI) indices. The results indicated that the share of water-related energy consumption (20%, 6%, and 2% of total electricity, crude oil, and natural gas consumption) is higher than the energy-related water withdrawal (17% of industrial water withdrawal) in the basin-wide resource usage. The water-saving policies had a significant impact on both the basin’s energy and water resources. In contrast, energy-saving policies had a negligible influence on the basin’s water resources but a notable impact on the water resources used in the energy sector outside of the basin. In addition, SD-WE model simulations showed that agriculture was the most effective end-user on resource saving, by improving WSI and ESI as much as 22% and 5.7%, respectively. Finally, the results of this study indicated that SD-WE model can be used as a tool to illustrate the inter-linkages, synergies, and trade-offs between water and energy systems, where limited water and energy data are available and also can be used as a platform for water–energy nexus modeling in other basins.