Urban food-energy-water nexus: a case study in Beijing

Abstract

Food, energy and water (FEW) are indispensable, irreplaceable and safeguarding resources with tangled interlinkages among each other, often framed in terms of ‘nexus’. Cities have become the bustling hubs of resource consumption and production, facing the most intense stress. Globally, food security, fresh water shortage and fossil energy exhaustion have become the greatest challenge for the sustainable development of cities in the future. Systematic analysis and simulation of dynamic evolution of urban FEW demand and supply and its nexus would add significant and practical value for macro-management such as ensuring the security of urban resource. Taking Beijing as the case study, we established a dynamic model for the FEW demand and supply from the perspective of cross-ectoral and cross-regional nexus with the Stella modelling platform, then it was run for simulating the dynamic changes and nexus characteristics of FEW during the interval between 2016 and 2035.The results showed that:①The gap between local production and demand of these three resources in Beijing will continue to increase. In 2035, Beijing will need 2.16 million tons of grain, 0.83 million tons of meat, 4.6 billion m3 of water and 91.65 million tons of standard coal of energy while the resources produced and supplied by locality independently will be 0.21 million tons, 0.23 million tons, 3.3 billion cubic meters and 16.5 million tons of standard coal respectively. Beijing has to draw on cross-boundary production to meet FEW-use with the increasing gap between local supply and demand. ②There is a developing trend of the absolute quantity of interaction among FEW. Structurally, the ‘outsourcing’ feature is obvious and the indigenous nexus links of three resources are shifting to back-end supply chain such as transportation and treatment. ③The change of nexus indexes are mainly affected by the mutual and strong dependence between food and water. Food and energy depend more and more on each other; in contrast, the inter-relationship between water and energy is more stable. In addition, inter-regional FEW nexus is strengthened. ④To improve systematic management of urban resources, we need to capture multi-tradeoffs of the FEW system comprehensively and establish a multi-regional and multi-factor integrated and collaborative resource management mechanism.