The carbon mitigation for water supply system has become a hot issue concerning carbon peaking and carbon neutrality goals of cities. This study aimed to establish an integrated water-carbon nexus model to account the carbon emissions of urban water supply system. First, the physical-virtual water inventory was established covering local water intake, water transfer, and virtual water imports. Then, the water-carbon nexus model was constructed to simulate the carbon emissions of each stage along the whole water supply chain. Regarding physical water supply, the carbon emissions of pumping station and valve combinations, and water delivery routes were accounted while those from virtual water imports embodied in water-intensive products were calculated as well based on the multi-regional input-output (MRIO) analysis. Finally, taking Beijing-Tianjin-Hebei region as a case, we conducted a scenario analysis in context of regional water resource planning and carbon mitigation goals during 2020-2030. This study may provide a novel integrated water supply optimization framework for coordinating regional water resource management and carbon mitigation activities.
Keywords water-carbon nexus, water supply system, virtual water, input-output analysis, water resource planning