The use of fossil energy sources causes a lot of ecological issues like the release of greenhouse gases. An alternate opportunitiy is the use of renewable energies. This thesis is about the potentials of renewable energies in Austria and their relevance to cover the demand for energy. The thesis starts with a description of the different types of renewable energies in Austria and their current use. The following chapter deals with the energy consumption in Austria. The amount of consumed energy will be subdivided into the three types heat, electricity and fuels. The demand for energy is not constant within a year. Therefore, the monthly course of the energy demand will be simulated. After that, the potentials of renewable energies in Austria will be described and also assessed, which amounts of heat, electricity and fuels could be provided by the use of them. Similar to the demand of energy, the supply of the renewable energies, for example photovoltaik conversion, depends on the season or month. So, in this thesis, the monthly courses of this supply will be assessed. Further, the energy, which is necessary to use the potentials will also calculated. At the end, the amount of energy, which appears due to the use of potentials and the current use of renewable energies will be compared with the demand of energy, including the necessary energy for using the potentials. So, the share of energy consumption, which could be supplied by renewable energies can be assessed. To show the relevance of energy efficiency, an alternate scenario will be generated. These scenario assumes, that the demand of heat is reduced, due to activities for the thermal redevelopment of buildings. With that, the impact of energy efficiency on the relevance of renewable energies should be shown. The result of this thesis is, that approx. 55 % of the energy demand could be supplied by renewable energies. With a higher energy efficiency, these share would rise to more than 60 %. In that case, the demand of heat could be covered by renewable energies for more than 80 %. In both scenarios, the demand of electricity could be completely covered by renewable energies.