Investigation of Climate Change Effect on Hydropower Energy Generation by Karun 4 Dam

Investigation of the potential impacts of climate change on hydropower generation and reservoir operation at the basin is a necessary issue. In this research, the effect of climate change on the generation of hydroelectric energy in the Karun 4 dam was investigated. For this purpose, after collecting the required data, temperature and precipitation variables were generated using general circulation models (GCM) under RCP4.5 and RCP8.5 climate scenarios for the upcoming period (2029-2050). Then, the temperature and precipitation values were downscaled for the future period using the changes factor method. The generated time series were used as inputs for the IHACRES rainfall-runoff model and the runoff were simulated under different scenarios. Then the effect of runoff variation under considered scenarios in the amount of generating hydroelectric energy was investigated. Climate predictions indicate an increase of 1.72 and 2.4° C in the long-term average annual temperature, and a reduction in the annual precipitation of 5% and 14% under the RCP 4.5 and RCP 8.5 scenarios, respectively, in the period of 2029-2050. The results of rainfall-runoff modeling indicate that the average annual inflow into the dam reservoir will be decreased 21% and 34% under the scenarios RCP 4.5 and RCP 8.5, respectively. In order to investigate the effect of runoff reduction on reservoir status and hydroelectric generation, the reservoir of Karun 4 Dam was simulated with WEAP software. The results showed that the generated hydroelectric energy by the Karun 4 Dam in the upcoming period (2029-2050) will be decreased by 17% and 31% under RCP 4.5 and RCP 8.5 scenarios, respectively.