Renewable energy sources ensure cleaner and more environmentally friendly energy. The potential to use the renewable energy in Slovenia is high and underexploited. Small hydropower plants are an important part of renewable energy and their developmental potential is still high. HYPSE programme has been developed to carry out multi-criteria decision-making methods in the siting of hydropower plants in an area. The advantage of computer support in the decision-making process is the increased number of processed information and the reduced number of biased decisions. The first part of the thesis is a theoretical introduction, which generally summarizes electricity, energy policy, renewable energy sources as well as emerging problems and solutions. It gives a general description of small hydropower plants and the impact of damming and water abstraction on aquatic ecosystems. The second part uses the HYPSE programme and the available data to make a comparison of six selected small hydropower plants. With an equivalently placed economic and environmental criteria and according to the annual amount of energy produced, a small hydropower plant is selected which has the minimum impact on the environment.