The dependency on fossil fuels is growing steadily, putting Europe's energy selfsustainability at massive risk. The recent political disturbances in Russia and Ukraine show how dangerous the situation is. If Russia decided to cut the gas supply, Austria's reserves would suffice for only few months. Meanwhile climate change is under huge progression due to GHG emissions, caused by the excessive use of traditional fuels. Establishing renewable sources of energy is the only way to change this situation. But can renewables prevail at currently low electricity and oil prices? The first part of this master's thesis covers the Austrian electricity market, economic and legal frameworks. Furthermore a short overview of the realisable RES potentials will be given. The core of this paper forms the analysis of five existing RES power plants with maximum capacities of 0,5 MW to 4,5 MW, and outputs of 2 GWh to 4,5 GWh, covering biomass combustion, photovoltaic, small hydropower and wind power technologies. The range of size has been chosen by the author because it is considered to be an optimal size for decentralised electricity production, being able to service communities 6from 1.000 to 2.000 inhabitants. The focus lies on the economic performance of the chosen plants, including dynamic investment calculations and evaluations of the electricity generation costs. Furthermore, sensitivity analyses will test the robustness of the results. In the last section the projects will be compared with traditional fuel based electricity-generating technologies.