Possible changes in future reservoir inflow and hydropower production potential under CMIP6 GCMs projections for the Dez Dam, Western Iran

Hydropower, derived from the power of flowing water, is a valuable and sustainable source of clean energy. It offers affordable electricity from local resources for multiple generations. However, the production of hydropower is vulnerable to the impacts of climate change. This study aims to assess how climate change affects the potential production of hydropower at Dez Dam in Western Iran. To do this, we used five General Circulation Models (GCMs) from the Coupled Model Intercomparison Project Phase 6 (CMIP6) to project future temperatures and precipitation. We applied the Quantile Mapping (QM) method to correct any biases in the GCMs' output for two Shared Socioeconomic Pathways (SSPs): SSP245 and SSP585, during the periods 2025–2054 and 2071–2100. We calibrated, validated, and used a regional Soil and Water Assessment Tool (SWAT) model to simulate future reservoir inflow. Next, we employed the River Basin Management Decision Support System (MODSIM-DSS) to quantify hydropower production in response to changing inflow. Our findings indicate that (1) temperatures are expected to increase in both future periods and SSPs, (2) different GCMs project different precipitation patterns, and (3) according to the average results from the five GCMs, reservoir inflow and hydropower generation are projected to decrease by 4% and 7% in 2025–2054, and by 8.6% and 13.8% in 2071–2100 under the worst-case scenario SSP585, respectively. These results provide valuable insights for long-term management planning and decision-making processes for the Dez hydropower plant.