With rise in population growth and increasing trend towards urbanization, urban spaces have become ‘hot spots’ for intensive resource use including water, energy and food (WEF). Thus, along with food production, food management from consumption side is equally important to address the issue of WEF resource scarcity. An analysis of urban food management in India was carried out through systematic study of different government documents. In-depth content analysis across five sectors, namely water, energy, food, urban and environment, was carried out to find parameters for urban food management strategies having linkage with WEF resources. The study identified six parameters under two categories, namely city region food systems (urban/peri-urban agriculture, green roof technology, urban farmers market) and managing food wastes (reducing food wastes, compost from waste, energy from wastes). The analysis revealed that urban food management in India is focused on managing food wastes through solid waste management strategies (compost and energy production). City region food system and role it plays in optimizing WEF nexus need the attention of policy makers. The study concludes that a paradigm shift is required towards integrated urban WEF policy to attain the goals of sustainable urban development in the developing nations of Global South.

The sustainability of food production systems is inherently linked with energy, water and food (EWF) resources directly and in-directly throughout their lifecycle. The understanding of the interdependencies between the three resource sectors in the context of food production can provide a measurable account for resource requirements, while meeting food security objectives. The energy, water and food Nexus tool developed by the authors has been designed to model the inter-dependency between energy, water and food resources, whilst conducting an environmental assessment of product systems. With emphasis on the inter-linkages between EWF resources, the tool quantifies material flows, natural resource and energy consumption at component unit process level. This work integrates greenhouse gas control and waste to power technologies within the energy, water and food Nexus tool and evaluates the environmental impact of a hypothetical food product system designed to deliver a perceived level of food self-sufficiency (40%) for the State of Qatar. Multiple system configurations, representative of different pathways for the delivery of consistent food products are evaluated, transforming a once linear product system into a circular design. The sub-systems added consist of a biomass integrated gasification combined cycle which recycles solid waste into useful forms of energy that can be re-used within the nexus. In addition, a carbon capture sub-system is integrated to capture and recycle CO2 from both the fossil fuel powered and the biomass integrated gasification combined cycle energy sub-systems. The integration of carbon capture with the biomass integrated gasification combined cycle transforms the carbon neutral biomass integrated gasification combined cycle process to a negative greenhouse gas emission technology known as bio-energy with carbon capture and storage. For the different scenarios and sub-system configurations considered, the global warming potential can be theoretically balanced (reduced by ∼98%) through the integration of photovoltaics, biomass integrated gasification combined cycle and carbon capture technologies. The peak global warming potential, i.e. a fully fossil fuel dependent system, is recorded at 1.73 × 10⁹ kg CO2 eq./year whilst the lowest achievable global warming potential is 2.18 × 10⁷ kg CO2 eq./year when utilising a combination of photovoltaics, carbon capture integrated with combined cycle gas turbine in addition to the integrated negative emission achieving system. The natural gas consumption is reduced by 7.8 × 10⁷ kg/year in the best case configuration, achieving a credit. In the same scenario, the photovoltaics land footprint required is calculated to a maximum of 660 ha. The maximum theoretically achievable negative emission is 1.09 × 10⁹ kg CO2/year.

Urban areas often face versatile stressors (e.g., food security, congestion, energy shortage, water pollution, water scarcity, waste management, and storm and flooding), requiring better resilient and sustainable infrastructure systems. A system dynamics model (SDM), explored for the urban region of Orlando, Florida, acts as a multi-agent model for portraying material and energy flows across the food, energy, water, and waste (FEWW) sectors to account for urban sustainability transitions. The interlinkages between the FEWW sectors in the SDM are formulated with multiple layers of dependencies and interconnections of the available resources and their external climatic, environmental, and socioeconomic drivers through four case studies (scenarios). The vital components in the integrated FEWW infrastructure system include urban agriculture associated with the East End Market Urban Farm; energy from the fuel-diverse Curtis H. Stanton Energy Center; reclaimed wastewater treated by the Eastern Water Reclamation Facility, the Water Conserv II Water Reclamation Facility, and stormwater reuse; and solid waste management and biogas generation from the Orange County Landfill. The four scenarios evaluated climate change impacts, policy instruments, and land use teleconnection for waste management in the FEWW nexus, demonstrating regional synergies among these components. The use of multicriteria decision-making coupled with cost-benefit-risk tradeoff analysis supported the selection of case 4 as the most appropriate option as it provided greater renewable energy production and stormwater reuse. The SDM graphic user interface aids in the visualization of the dynamics of the FEWW nexus framework, demonstrating the specific role of renewable energy harvesting for sustainably transitioning Orlando into a circular economy.

Secure and efficient supply for the food, energy and water resources is essential for sustainable urban development. Due to the close interaction of food, energy and water systems, it is necessary to analyze food-energy-water nexus from an integrated perspective. Taking the Detroit Metropolitan Area as a case, this study first constructs a food-energy-water physical input-output model to quantify food, energy and water flows. Then, structural path analysis is adopted to identify critical supply chain paths driven by the final demand of key sectors. Quantitative results of food-energy-water flows show that major inputs of food and energy in the Detroit Metropolitan Area are from outside through imports, while water use is predominately extracted from local sources. Local consumption activities for the food, energy, and water systems are mainly concentrated downstream of the supply chain. Structural path analysis results show that intermediate processes use relatively large amounts of food, energy and water, and should be more concerned. Also, identifying sectors involving multiple systems, such as Food Processing, Domestic Consumption, Solid Waste Management, Wastewater Treatment, and Residual Processing, can promote co-benefit opportunities. This holistic view on urban FEW nexus presented in this study can facilitate better decisions and help avoid unintended consequences.