A review on food subsystem simulation models for the water-food-energy nexus: development perspective.

Agricultural crops are the primary food source because livestock and poultry products also indirectly depend on crops. A significant obstacle to adopting the water, food, and energy (WFE) nexus is the lack of a comprehensive and easy-to-use simulation model for the food subsystem focusing on crops. By reviewing the articles in Scopus and Google Scholar databases, WFE nexus studies can be divided into two categories: simulation-based and conceptual-based studies of WFE nexus. Based on the developmental perspective on food subsystem modeling in the WFE nexus, the conceptual studies were excluded, and the modeling studies were reviewed. Two points of view can be used for WFE nexus modeling: 1. hard-link modeling and 2. soft-link modeling. Comparing these two types of modeling showed that hard-link modeling cannot model the interrelations of the food subsystem, and this shortcoming is of great importance. This study reviewed the crop growth models (CGMs) used in the WFE nexus system from the development perspective. The technical characteristics of the CGMs have been evaluated according to the requirements of the CGMs. Finally, a checklist based on the criteria defined for the nexus system has been provided, which can guide researchers in choosing the appropriate CGMs for the food subsystem with the nexus approach. The analysis revealed that none of the CGMs studied alone were sufficient to develop a simulation model for the food subsystem with the WFE nexus. However, the AquaCrop model met more criteria.

Framing a novel holistic energy subsystem structure for water-energy-food nexus based on existing literature (basic concepts).

It is interesting to note that the country of Iran is essential in terms of energy production and consumption, and the economy of Iran is mainly dependent on energy revenues. Therefore, thermal and hydropower plants consume water to produce various energy carriers. Considering that Iran is suffering from water stress, the nexus of water and energy becomes very important. This paper frames a comprehensive structure for Iran's energy subsystem within the Water, Energy, and Food (WEF) nexus system. The energy subsystem's supply and demand side in the proposed framework are formulated using data and physic-based equations. The presented framework addresses most interactions between WEF subsystems in a dynamic and adaptive setting. It is shown that through analysis of binding interactions between WEF, different management scenarios can boost the flexibility of the supply and demand side of the energy subsystem. In addition, by incorporating this framework, the water subsystem will manage the allocated and consumed water on the supply side and arrive at the most desirable outcome for the water sector. Also, the optimal cropping pattern could be evaluated based on energy consumption.

A new paradigm of water, food, and energy nexus.

In recent decades, global forecasts show that the demands for freshwater, energy, and food have been affected by population growth, economic development, international trade, and increasing urbanization and food diversity. Moreover, cultural changes and other phenomena have adversely affected the water, energy, and food (WEF) resources demand. Consequently, climate change adverse impact, which is an undesirable phenomenon, will be increased at a staggering rate. Numerous studies have emphasized that the lack of integrated and systematic management strategies threaten these indispensable resources' ability to meet growing demand. In many countries, the security of WEF resources, which is related to each other, has become three non-traditional security challenges that overshadow these communities' development. Before realizing the importance of interactions between these three vital resources, the management strategies were typically used for one source, which was completely independent of the other two. Since these strategies did not consider the interactions between the three systems, the applied strategies' results were sometimes contradictory. Also, due to the lack of attention to these three sectors' vital connections, the competition level among these systems has been increased. Therefore, in recent years, the study of the complex interactions and connections between these resources has led to the emergence of a new term called WEF nexus in the scientific communities. Most studies about the WEF nexus have only described the current situation or, ideally, analyzed several predetermined scenarios. However, the adopted approach should be able to analyze different scenarios and be efficient and robust enough to develop a variety of strategies and utilize them for macro-policies. In this study, after reviewing the complex interactions between the WEF systems, it was tried to introduce a novel paradigm for the WEF nexus, which concentrates on expanding the possible space of WEF nexus.

Energy simulation modeling for water-energy-food nexus system: a systematic review.

Since essential nexus variables were not considered in the energy subsystem, this study focused on the role of energy in the Water, Energy, and Food nexus (WEF nexus) system. The energy subsystem interacts with water and food on the supply and demand sides. The WEF nexus-based energy model has not been reviewed recently. This study provides a systematic review of 459 articles regarding energy simulation modeling issues relating to the WEF nexus system. The keyword ("energy" AND "simulation" AND "nexus") as well as "water" OR "food" OR "climate" OR "land" OR "carbon" OR "environment" is used for searching WEF nexus documents for energy simulation. The review highlighted that the energy subsystem is modeled online (One-way) and offline (Two-way), and the energy simulation struggles to represent its system boundary with the water and food subsystems in different spatial scales (household to global). The energy subsystem of the WEF nexus did not address return flow from cooling towers and crop energy consumption comprehensively. In the research, the supply and demand section of the energy subsystem demonstrated that a comprehensive simulation model for energy can be developed using the nexus system approach. The energy subsystem's supply, primarily power plants, interacts with the water subsystem, and the energy generation policy is based on water use. The WEF nexus system assesses renewable energy effects to reduce tradeoffs. In addition, energy demand is related to energy consumption, so the energy consumption for each crop can be calculated and explained the appropriate cultivation pattern based on it.