System dynamic analysis of urban household food-energy-water nexus in Melbourne (Australia)

Ensuring the security of food, energy and water plays an important role in developing circular economy and building resilient cities. Based on system dynamics, this study establishes a household food-energy-water nexus model, taking Melbourne as a case. Three regulation measures, including appliance, behavior and price intervention, are analyzed to predict the dynamic consumption of food, energy, and water from 2010 to 2050. The water, energy and carbon saving effects are evaluated under 4 scenarios and 37 sub-scenarios. Results show that residents' behavior adjustments are the most significant in reducing resource consumption, and the effects of replacing appliances and resource price adjustments are weak. Compared with the BAU scenario, reducing the use frequency of the dishwasher to 3.5 times per week brings the best water saving effect, equal to 20680 L per household per year, followed by using the 4-star shower heads. Extending residents' water-saving and energy-saving behaviors retention to four years will bring the best energy-saving effects. In addition, adjusting the proportion of meat and dairy in residents' diets can only reduce carbon emissions in the short term. The insights achieved in this work may support policy makers in guiding households transition to sustainable behaviors and to pay attention to carbon emissions in the food sector. This method is also applicable to food-energy-water cross-sectoral decision-making in other cities.