Prioritization of water-energy nexus scenarios using the development of D-number theory in multi-criteria analysis method

Abstract

The dam and hydropower plant in the Marun basin located in southwestern Iran have faced severe challenges in recent years in providing agricultural irrigation water and domestic electricity due to the adverse effects of climate change and population growth. To overcome these challenges, 11 strategies as water-energy nexus scenarios were discussed. For this purpose, first, the effects of climate change on temperature and precipitation variables were examined in three concentration pathway (RCP) RCP2.6, RCP4.5, and RCP8.5 from fifth report of International Panel on Climate Change (IPCC). Then, the inflow to the reservoir and the irrigation water required in the future time period were calculated using the artificial neural network and Cropwat models, respectively. The water system was modeled in the water evaluation and planning (WEAP) model, and the energy system was modeled in the low emissions analysis platform (LEAP) model and then coupled with each other. Considering the field situation of the Marun basin, 11 water-energy nexus (WEN) scenarios and nine nexus indexes for evaluating the scenarios were proposed by the expert group. In order to select the best scenario in the future time interval, the ordinal priority approach (OPA) decision-making method integrated with D-number theory was used. The results reveal that the maximum water-energy nexus sustainability index under RCP 2.6, RCP 4.5, and RCP 8.5 scenarios are 31.56, 34.3, and 34.9 for the WEN4 (i.e., reducing the weeds and vegetables cultivation area by 30%), WEN7 (i.e., reduction in the grain maize and vegetables cultivation area each by 5% units and increasing forage crops cultivation area by 10% units), and WEN11 (i.e., decreasing household electricity consumption intensity by 20% throughout increasing electricity tariffs) scenarios, respectively. Also, the results of the OPA method show that the most important index in evaluating the nexus scenarios is the energy sector sustainability index with a weight of 0.142, and the best nexus scenario is the WEN7 scenario with a final weight of 0.189. The comprehensive decision-making process within the comprehensive framework of the water-energy nexus under the impact of climate change, presented in this study, can easily be adopted and applied in other river basins because of verified tools in water and energy, explicit steps, and available initial data.