Managers of federal, state, local, and nonprofit organizations around the world are faced with the complex task of managing interconnected systems of scarce resources. One key example of this has been the recent research on the connections between water, energy, and food/agriculture, and the problem of managing these resources to be sustainable and reduce the likelihood of resource depletion. While engineering research has focused on achieving greater efficiencies in resource management, less attention has been given to issues of governance within the fragmented, decentralized, and polycentric systems that are responsible for resource delivery. The central question animating this paper is whether resource management decisions in water, energy, and food are siloed, and what theoretical frameworks can be leveraged to develop strategies to break down existing silos. Results from a survey of water agencies suggests that there is little communication between the water, energy, and food policy areas. If achieving greater nexus requires increased communication and repeated interactions, there is significant work to be done to re-think how policy and management are organized and conducted.

Continued rise in global human population, per capita consumption, urbanization and migration towards coastal cities present challenges in fulfilling the energy, water and food demands of coastal communities in sustainable manner. In this regard, as a solution to the problem, a new multigeneration system is proposed to address some of the most common and vital needs of such communities. The system developed is based on principles of sustainability and decentralisation and is driven by renewable energy sources including sun and biomass. It provides electricity, fresh water, hot water for domestic use, HVAC for space air-conditioning and food storage, in addition to hot air for food drying. In the proposed hybrid system, biomass energy is integrated with solar energy in a complimentary manner as a means to maximise outputs and enhance system resilience against weather conditions and day/night cycles. Designing for resilience enables a type of operation that fulfils parallel demands in a continuous stable and flexible operation which can be optimised depending on the requirements. The main sub-systems used in the proposed multigeneration system consist of a Biomass combustor, Concentrated Solar Power (CSP), a Rankine Cycle, a desalination unit and an Absorption Cooling System (ACS). A comprehensive integrated thermodynamic model of the entire system is developed by application of energy, mass, entropy and exergy balance equations. Moreover, effects of various inputs and environmental variables on the outputs and performance has also been studied. Results reveal that the proposed system is capable of fulfilling some of the coastal community’s essential requirements in an efficient and ecologically benign manner. The energy and exergy efficiencies of the proposed system are 55% and 18%, respectively. The outputs of the system include 1687 m³/day of produced fresh water, ~4 MW of cooling, ~13 MW of electricity, ~73 kg/s of hot air for food drying, and ~41 kg/s of hot water for domestic use. Furthermore, the highest amount of exergy destruction is observed in biomass combustion unit and the solar PTCs.

The paper aims to understand the impacts of the spatial and temporal diffusion of Anaerobic Digestion (AD) on the Water Energy Food (WEF) nexus and to quantify the associated environmental, social and economic benefits. Contemporary tight carbon reduction targets urge the need to deploy renewable energy technologies however due to interdependencies across the WEF nexus, various technologies are beneficial for some but not all sectors. This paper quantifies the impacts of future possible AD technology diffusion choices on the environment, society and economy. This can aid decision makers to identify the potential consequences of various AD alternatives within the next three decades. The study considers an integrated WEF nexus approach and accounts for the interdependencies within the nexus. This was done by developing an Agent-Based Model (ABM) and simulating the relations between the main players within the nexus, thus examining the upscaling of AD diffusion and its consequences for water consumption, energy production, transportation, landfill use, food waste processing and digestate generation. Three future WEF nexus scenarios, that reflect potential alternatives of society and technology in Great Britain up to 2050, were utilised by the ABM implementation to test the sensitivity of AD diffusion choices. These scenarios describe possible changes to lifestyle, governance, technologies, climate, and social structures. Accounting for the uncertainty associated with such future simulations, the Monte Carlo method was employed to estimate the potential variations in scenario outputs. Results suggest that decentralisation results in the largest carbon reduction, but can incur more costs. Centralisation consumes 35% more water but produces 37% more energy (biogas). The paper has visualised the scenario outputs graphically to highlight the consequences of neglecting the inter-relationships between environmental, social and economic aspects of AD.