Throughout the world, much food produced is wasted. The resource impact of producing wasted food is substantial; however, little is known about the energy and water consumed in managing food waste after it has been disposed. Herein, we characterize food waste within the Food-Energy-Water (FEW) nexus and parse the differential FEW effects of producing uneaten food and managing food loss and waste. We find that various food waste management options, such as waste prevention, landfilling, composting, anaerobic digestion, and incineration, present variable pathways for FEW impacts and opportunities. Furthermore, comprehensive sustainable management of food waste will involve varied mechanisms and actors at multiple levels of governance and at the level of individual consumers. To address the complex food waste problem, we therefore propose a “food-waste-systems” approach to optimize resources within the FEW nexus. Such a framework may be applied to devise strategies that, for instance, minimize the amount of edible food that is wasted, foster efficient use of energy and water in the food production process, and simultaneously reduce pollution externalities and create opportunities from recycled energy and nutrients. Characterization of FEW nexus impacts of wasted food, including descriptions of dynamic feedback behaviors, presents a significant research gap and a priority for future work. Large-scale decision making requires more complete understanding of food waste and its management within the FEW nexus, particularly regarding post-disposal impacts related to water.

Many studies examine the correlation between the use of resources such as water, energy and land, and the production of food. These nexus studies focus predominantly on large scale systems, often considering the social dimensions only in terms of access to resources and participation in the decision-making process, rather than individual attitudes and behaviours with respect to resource use. Such a concept of the nexus is relevant to urban agriculture (UA), but it requires customisation to the particular characteristics of growing food in cities, which is practiced mainly at a small scale and produces not only food but also considerable social, economic, and environmental co-benefits. To this end, this paper proposes a new conceptual basis for a UA Nexus, together with an assessment methodology that explicitly includes social dimensions in addition to food, energy and water. The conceptual basis introduces People, together with Food, Energy and Water, as a fundamental factor of the UA Nexus. On this basis, a methodology is developed measuring not only resource efficiency and food production but also motivations and health benefits. It comprises a combination of methods such as diaries of everyday UA practices, a database of UA activities, life cycle assessment (LCA), and material flow analysis to connect investigations developed at a garden scale to the city scale. A case study shows an application of the methodology.

Optimal allocation of the food, energy and water (FEW) resources is of emergent concern owing to depleting supply of the natural resources. Increasing demand for the FEW resources is attributable to growing population, migration, economic development, technological advancements and climate change. The FEW nexus (FEW-N) is an intricate system that requires robust quantitative decision-making tools to investigate the links between the various system components and sustainability. This study proposes a meta-model-based FEW-N system for addressing the issue of natural resource allocation for food and energy security. It incorporated an integrated model consisting of the Techno-Economic and Input/Output models in an Optimisation framework with maximum economic benefit as its objective function. The COINOR Branch and Cut (CBC) and CPLEX solvers in the Advanced Interactive Multidimensional Modelling System (AIMMs) were used to formulate and solve the optimisation problems. To validate the developed framework, the scenario analysis was performed on three cases in South Africa. First, it was found that using FEW resources for food production in dryland open fields, undercover greenhouses, and irrigated open fields was more profitable than for production of electrical energy from bioenergy, solar/wind-based hybrid renewable energy, and hydropower production systems. Second, the revenue of the sub-sector determined the percentage use of the FEW resources and the percentage contribution of technology options to food and energy security. Third, open fields, greenhouses, and irrigated open fields contributed significantly to food security. The holistic framework developed provided enhanced understanding of the FEW-N system. Resource security has significantly improved due to the ability of various technologies in each subsector to meet the food and energy demands of the specific population. Besides providing scientific support for national decisions regarding food, energy, and water policy, the proposed framework will also contribute to sustainable development at the subnational level.

There is a growing recognition of the interdependencies among the supply systems that rely upon food, water and energy. Billions of people lack safe and sufficient access to these systems, coupled with a rapidly growing global demand and increasing resource constraints. Modeling frameworks are considered one of the few means available to understand the complex interrelationships among the sectors, however development of nexus related frameworks has been limited. We describe three open-source models well known in their respective domains (i.e. TerrSysMP, WOFOST and SWAT) where components of each if combined could help decision-makers address the nexus issue. We propose as a first step the development of simple workflows utilizing essential variables and addressing components of the above-mentioned models which can act as building-blocks to be used ultimately in a comprehensive nexus model framework. The outputs of the workflows and the model framework are designed to address the SDGs.

Analysis the water–food–energy nexus is the first step to assess the decision maker in developing and evaluating national strategies that take into account the nexus. The main objective of the current research is providing a method for the decision makers to analysis the water–food–energy nexus of the crop production system at the national level and carrying out a quantitative assessment of it. Through the proposed method, indicators considering the water and energy consumption, mass productivity, and economic productivity were suggested. Based on these indicators a water–food–energy nexus index (WFENI) was performed. The study showed that the calculated WFENI of the Egyptian summer crops have scores that range from 0.21 to 0.79. Comparing to onion (the highest scoring WFENI,i.e., the best score), rice has the lowest WFENI among the summer food crops. Analysis of the water–food–energy nexus of forty-two Egyptian crops in year 2010 was caried out (energy consumed for irrigation represent 7.4% of the total energy footprint). WFENI can be applied to developed strategies for the optimal cropping pattern that minimizing the water and energy consumption and maximizing their productivity. It can be applied as a holistic tool to evaluate the progress in the water and agricultural national strategies. Moreover, WFENI could be applied yearly to evaluate the performance of the water-food-energy nexus managmant.

Water, energy, and food are essential for human well-being and for sustainable development. Water is required in almost all types of electricity generation and it is highly consumed in food production. Cities, industry, and crop production have increased their needs for water, energy and land resources, and at the same time, they are facing problems associated with the environmental degradation and, in some regions, resource scarcity. This paper proposes a multiobjective optimization model for the design of a water distribution network from a water–energy–food nexus point of view. Additionally, crop production and cost relationships are integrated to account for the water and energy requirements in the agricultural sector. The economic objective is the maximization of annual gross profit, which accounts for the water, energy and food production; the environmental objective establishes the minimization of overall greenhouse gas emissions, and the social objective is the maximization of the number of jobs. In this paper, because the objectives are opposites, a multistakeholder assessment is proposed in order to analyze and quantify the relationship of the water–energy–food nexus to assess synergies that improve the decision-making process. The mathematical model was applied to a case study located in the Sonoran Desert in Mexico, in which, a series of scenarios were solved to illustrate the capabilities of the proposed optimization approach. The results show strong trade-offs between the considered objectives as well as the quantification of the water–energy–food nexus.