In the study area, due to the impact of climate change on hydropower generation and energy demand has been investigated the impact of climate change on hydropower generation, and the changes between demand and supply. To predict hydropower generation is utilized Representative Concentration Representative (RCPs) scenarios. Due to the effect of various influential factors such as climate, economy, and social on energy demand, in this study, a proposed model is used to increase the accuracy of energy demand forecasting. This model is an optimal Artificial Neural Network (ANN) model using the Developed Pathfinder Algorithm (DPA) The results of forecasting the climatic parameters showed that in the next 25 years, the temperature will increase and rainfall will decrease. Changes in hydropower generation under RCP2.6 and RCP 8.5 163.3 MW and 188.3 MW will be less than the base time. The results of the energy demand simulation showed that due to the impact of population, Gross Domestic Product (GDP), and rising temperatures, society would face an increasing trend of energy demand. However, this demand will be higher in some seasons due to the increase in the consumption of cooling devices. The electricity demand increased by about 91.42 MW compared to the base period. Examining the changes in demand and energy production, it was found that energy demand would be higher than energy production. Therefore, there is probably a shortage of energy in the future.