Poland’s accession to the EU has caused a necessity of harmonising Polish with the union law also in the field of energy law. It also enforces achievement of 7,5% share of energy from alternative sources in the total energy consumption in 2010. Execution of this international commitment will require more economic and legal support from the state. The development of alternative sources of energy creates chances of development of rural areas where these kinds of installations are being mostly located. This article presents an analysis of the economic efficiency of energy production on an example of 5 small hydroelectric power stations. The analysis is based on a comparison of full unit costs and unit revenue from energy sale. Bigger stations proved economically efficient while for the smaller the break even point is associated with an average water flow of 153 million m3/year.