A new city's water–energy nexus implications: The case of Sejong City in South Korea

Cities’ impact on water, energy, and greenhouse gas (GHG) emissions is increasing as the world becomes more urbanized. Focusing on Sejong City, which was developed as a new administrative hub in South Korea in 2012, this study scrutinizes its development path from water–energy nexus perspective by developing a system dynamics model that describes the interactions among numerous components related to water and water-related energy consumptions. Furthermore, this study reimagines the city's potential development trajectories by constructing nine policy scenarios that combine different degrees of water conservation ambitions with different amounts of decarbonization in the power sector. The results confirmed the potential of water conservation policies. The expansion of rainwater use has the potential to cut water use by 50% from the 2050 baseline levels. Although the use of harvested rainwater is negligible compared to wastewater reuse, its overall effect on water conservation would be substantial if it is increased. The maximum reduction in GHG emissions from the water sector would be 9.36% from the 2050 baseline scenario when combined with decarbonizing the power sector. Although this study does not fully account for the water conservation potential, including the efforts at the end-use stages, the possibility of carbon neutrality in Sejong's water sector by 2050 is presented. It affirms that local governments can significantly reduce cities’ environmental footprints and complement national efforts for the transition to a carbon-neutral society.