Economic and Energy Efficiency of Net-Zero Water Communities: System Dynamics Analysis

A net-zero water (NZW) community can be developed by combining various water supply sources, conservation measures, and water reuse approaches over time. A decision support system is required to assess the site-specific economic and environmental potential of NZW development. This paper develops a cost module and size-dependent energy submodule in the existing water-energy-carbon (WEC) nexus model. The model has been used to analyze the economics of the WEC nexus to achieve NZW in the City of Penticton (British Columbia, Canada) between 2016 and 2025. The uncertainty of the results was approximated using Monte Carlo simulations. Results show Penticton can achieve net-zero to net-plus water, but it would be highly energy intensive and costly. A detailed analysis shows that rainwater harvesting and wastewater reuse could be energy efficient and cost effective given certain annual precipitation and freshwater conveyance distances, respectively. The energy efficiency and cost effectiveness of NZW would increase with an increased pressure on water sources because of population growth, decreasing freshwater availability associated with climate change, and so on. (C) 2018 American Society of Civil Engineers.