The use of renewable energies can ensure a sustainable, environmentally responsible energy future for Europe. Due to the EU?s energy policy and climate change objectives for the year 2020, European countries are striving to increase the use of renewable energy sources for electricity generation. For this reason this thesis intends to highlight the role of renewable energies in Spain and Portugal and presents the potentials for using renewable energy sources as well as the national energy policy goals. Based on an extensive literature research, a review of the current status of the Iberian electricity system is presented. The main part of this work is a GIS-based hydrological analysis, which reflects the theoretical hydropower potential of the Iberian Peninsula. The model which was developed for this purpose, calculates a theoretical hydropower potential along rivers, on the basis of a digital elevation model, rainfall data and evaporation data. In addition to an annual assessment for the whole Iberian Peninsula, the Ebro basin potentials are calculated on a monthly basis. The annual theoretical hydropower potential, calculated via the actual evaporation for the major river basins of the Iberian Peninsula, amounts to a total of 239 TWh. To calculate the monthly potential for the Ebro basin, the potential evaporation is used, because it supplies acceptable results in the northern regions. In this case, the months November, December and January show the greatest potentials with 8.000-12.000 GWh. Other GIS-based analysis, which use climate data such as the mean wind speeds and data of the solar radiation, create an impression of the climatic and natural conditions which are relevant for the use of renewable energy. This analysis gives knowledge about the suitability for the use of wind power and solar radiation for each region.