A comprehensive energy simulation model for energy-water-food nexus system analysis: A case study of the great Karun water resources system

Abstract

Focusing on the importance of energy in the Energy, Water, and Food (EWF) nexus, this study develops a comprehensive energy simulation under the EWF nexus system approach (CESNeX). The simulation model employs an effective template for planning and decision-making in the nexus system. The CESNeX simulates the energy subsystem in both the demand and supply sides as required in the nexus simulation of EWF on a river basin scale, considering nexus variables. The CESNeX evaluates the effects of various energy generation scenarios on the water subsystem by interacting with the principal nexus variables on the supply side of the energy subsystem. In the comprehensive simulation of the nexus system, the CESNeX can interact with water and food subsystems via nexus variables and provide the energy-efficient cropping pattern. The demand side of CESNeX can assist policymakers in developing an appropriate cropping pattern, considering water and energy consumption. Additionally, the supply side of CESNeX can provide the produced energy based on water consumption and the change in the reservoir head. 14 years of data (2008–2021) from the Great Karun Basin's Karun-4, Karun-3, Karun-1, Masjed Soleyman, Gotvand, and Dez reservoirs are utilized for the simulation's calibration, verification, and modelling. On the supply side, results revealed that by increasing the nexus variable of Karun-4's firm energy by about 5%, the reservoir net head is related to the Karun-3 power plant decreased by 1.93 m. Also, the largest increase in net reservoir head was related to the Karun-1 power plant, about 54 cm. There has also been a decrease of 18 MCM and an increase of 25.8 MCM in the volume of water used by the turbines at the aforementioned power plants, respectively. On the demand side, results of receiving nexus variables from the water and food subsystems showed that Potato has the highest energy consumption (150 PJ), while Barley has the lowest (20 PJ). In terms of water consumption, Potato and Barley have the highest (3.5 BCM) and lowest (1.5 BCM) water requirements, respectively. This study suggests expanding Barley cultivation in the region under consideration. Barley requires significantly less water and energy than other crops. In addition, based on the results of the CESNeX simulation model, it is recommended that less Potato be grown in this region due to its relatively higher water and energy needs.