The water-energy-food nexus and process systems engineering: A new focus

A hierarchical Food-Energy-Water Nexus (FEW-N) decision-making approach for Land Use Optimization

The land use allocation problem is an important issue for a sustainable development. Land use optimization can have a profound influence on the provisions of interconnected elements that strongly rely on the same land resources, such as food, energy, and water. However, a major challenge in land use optimization arises from the multiple stakeholders and their differing, and often conflicting, objectives. Industries, agricultural producers and developers are mainly concerned with profits and costs, while government agents are concerned with a host of economic, environmental and sustainability factors. In this work, we developed a hierarchical FEW-N approach to tackle the problem of land use optimization and facilitate decision making to decrease the competition for resources and significantly contribute to the sustainable development of the land. We formulate the problem as a Stackelberg duopoly game, a sequential game with two players - a leader and a follower (Stackelberg, 2011). The government agents are treated as the leader (with the objective to minimize the competition between the FEW-N), and the agricultural producers and land developers as the followers (with the objective to maximize their profit). This formulation results into a bi-level mixed-integer programming problem that is solved using a novel bi-level optimization algorithm through ARGONAUT. ARGONAUT is a hybrid optimization framework which is tailored to solve high- dimensional constrained grey-box optimization problems via connecting surrogate model identification and deterministic global optimization. Results show that our data-driven approach allows us to provide feasible solutions to complex bi-level problems, which are essentially very difficult to solve deterministically.

Perception and Representation of the Resource Nexus at the Interface between Society and the Natural Environment

Recent years have seen an explosion of interest in the resource nexus. This has created the co-existence of different understandings and uses of the concept. In this regard, experiences in the EU H2020 project ‘Moving towards adaptive governance in complexity: Informing nexus security’ are consistent with findings reported in the literature: (i) The inconvenient message of the nexus is difficult to get across, it being incompatible with the currently dominant rosy narratives about sustainability. Indeed, from a historic perspective, the nexus can be seen as a revival of the ideological fight between cornucopians and neo-Malthusians; (ii) Silo structures in existing institutions are a problem for the governance of the nexus, and so is the resulting reductionist strategy of addressing and fixing one issue at the time; (iii) Scientific inquiry is currently not providing the quality inputs needed for a meaningful discussion of the resource nexus. Entanglement of resource flows is rooted in the complex metabolic pattern of social-ecological systems, the analysis of which requires a complex systems approach and relational analysis. Contemporary reductionist models simply make the nexus invisible to the analyst.

Towards a Quantitative Food-Energy-Water Nexus Metric to Facilitate Decision Making in Process Systems: A Case Study on a Dairy Production Plant

While the importance of the Food-Energy-Water Nexus (FEW-N) has been widely accepted, a holistic approach to facilitate decision making in FEW-N systems, along with a quantitative index assessing the integrated FEW-N performance is rather lacking. In this work, we propose a FEW-N metric along with a framework to facilitate decision making for FEW-N process systems through a FEW-N integrated approach. The framework and metric are illustrated through a case study on a dairy production and processing plant. The dairy industry is a significant user of water and energy, with water being a top issue for most dairy industries and organizations worldwide. Following the framework, we develop a mixed-integer scheduling model, with alternative pathways, that faithfully replicated the major food, energy, and water aspects of a real cottage-cheese production plant. Using the developed FEW-N metric we were able to optimize the cottage-cheese plant process and observe different trade-offs between the FEW-N elements.

Insight-Based Approach for the Design of Integrated Local Food-Energy-Water Systems

Society currently relies heavily on centralized production and large scale distribution infrastructures to meet growing demands for goods and services, which causes socioeconomic and environmental issues, particularly unsustainable resource supply. Considering local production systems as a more sustainable alternative, this paper presents an insight-based approach to the integrated design of local systems providing food, energy, and water to meet local demands. The approach offers a new hierarchical and iterative decision and analysis procedure incorporating design principles and ability to examine design decisions, in both synthesis of individual yet interconnected subsystems and integrated design of resource reuse across the entire system. The approach was applied to a case study on design of food-energy-water system for a locale in the U.K.; resulting in a design which significantly reduced resource consumption compared to importing goods from centralized production. The design process produced insights into the impact of one decision on other parts of the problem, either within or across different subsystems. The result was also compared to the mathematical programming approach for whole system optimization from previous work. It was demonstrated that the new approach could produce a comparable design while offering more valuable insights for decision makers.