The Intergovernmental Panel on Climate Change (IPCC 2013) concluded with high confidence that the atmosphere is warming because of the anthropogenic activities and this fact can affect to the climatic conditions. Considering that the 99% of total energy produced in Norway comes from hydropower, it is essential to predict the future climatic conditions in order to be able to anticipate and design the future hydropower systems to manage the water resources. This study is carried out in the south of Norway, in 3 different stations of Vest-Agder County. The Regional Climate Models (RCM) are downloaded from Coordinated Regional Climate Downscaling Experiment (CORDEX) with a total of 5 models and 9 scenarios, according the new scenarios described in 5th assessment report (AR5). These models are used to perform an assessment. Further downscaling is needed for hydrology processes, so a bias correction method by Torill Engen-Skaugen is applied to dynamically downscaled precipitation and temperature. Then, these outcomes are compared to the observed data, the station values with delta change applied, and old scenarios described in the Special Report on Emissions Scenarios (SRES) in 2007. In the case of temperature, the bias correction Engen-Skaugen method is found satisfactory but the same adjustment in precipitation does not perform very well. After, the Hydrologiska Byråans Vattenbalansavdelning (HBV) is chosen to proceed with the thesis. The model calibration is done based on the real observation data from Kjevik station and Myglevatn river flow in the period 1995-2000 obtaining a R2 value of 0.71 and validated in 3 different five-years periods. Next, statistically downscaled data from Kjevik is selected to proceed running all models and scenarios with the HBV. A slight increase in addition to seasonal changes is found in runoff and a significant decrease of the snowpack and snowmelt are predicted for that location in the future period (2071-2100). Finally, runoff outputs from HBV are used as an input for the Nmag model in the Mandal catchment. The study focus on the Laudal power plant, situated in the lowest point of the mentioned catchment, and how can it be affected according to these future predictions. Not only seasonal changes are found in the inflow but also an increment in the total annual inflow. Besides that, a modest increment is predicted in the future annual power production in Laudal. In conclusion, this study has been successfully carried out not only how the global warming will impact Vest Agder County and the Laudal power plant in the future, but also to examine the results of the application of the Engen-Skaugen bias correction method for local scales and the comparison to other downscaling methods.