Parisa-Sadat Ashofteh

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.

In this study, the water-energy nexus is investigated throughout coupling the Water Evaluation and Planning (WEAP) and Low Emission Analysis Platform (LEAP) models under the climate change effects in the Marun basin, Iran. For this purpose, first, the climate change effects on water resources and consumption nodes are calculated under representative concentration pathway (RCP) scenarios from the fifth report of the International Panel on Climate Change (IPCC). Artificial neural network (ANN) is used to model river inflow and Cropwat model is used for agricultural water demand in future time (2015–2040). In the next step, water system is modeled in WEAP and energy system is modeled in LEAP. Then, three water-energy nexus scenarios include (1) calculating the actual hydropower generation capacity in LEAP model (W-E-N1), (2) water-energy nexus evaluation indexes in the WEAP model (W-E-N2), and (3) changes in the electricity consumption intensity in the LEAP model (W-E-N3) are modeled under RCP 2.6, RCP 4.5 and RCP 8.5 climate scenarios. The results of W-E-N1 scenario show that the actual hydropower generation capacity with water-energy nexus is reduced by 78%, 89%, and 91%, respectively, compared to no water-energy nexus under RCP 2.6, RCP 4.5, and RCP 8.5 scenarios. The results of W-E-N2 show that the hydropower generation reliability index will be reduced by 19%, 31%, and 13%, respectively under RCP 2.6, RCP 4.5, and RCP 8.5 compared no water-energy nexus. The results of W-E-N3 scenario show that the electricity consumption intensity will increase considering the electricity required for water transferring to demand sites. The results of the present study show that the water-energy nexus will lead to more accurate results and, as a result, more realistic planning for water and energy resources.