Nowadays, the main non-renewable fuels are coal, crude oil and their derivatives. The gradual exhaustion of deposits of these materials and high increase in their prices in the last decade resulted in increased intensity of the search for alternative energy sources. Biogas is one of the alternative energy sources, produced during anaerobic digestion of biomass. It contains methane, carbon dioxide and small amounts of nitrogen, hydrogen sulphide and hydrogen. The possibilities of biogas application and the environmental aspects associated with the production of biogas constitute an interesting topic, especially in view of the commitment to reduce emissions of carbon dioxide, imposed on the member states of the European Union. The choice of technology for biogas production, determined by the type of substrate used, is a crucial issue. In spite of the great number of farm biogas plants all over the world, research aimed at the optimisation of technology of biogas production and at reducing the production cost and the threat to the environment is still continued.

This paper presents the technical and technological aspects related to the production and application of biogas produced in farm biogas plants. It describes the legal and economic aspects related to the construction of biogas plants in Poland.

The paper contains basic information about anaerobic digestion and parameters such as temperature, pH, retention time, nutrients or mixing. These are the crucial parameters which determine the stability and efficiency of the process. The authors describe the applicability of biogas for the production of electric and thermal power and its application in the gas networks and as a vehicle fuel. The technologies for biogas production and cleaning applied in biogas plants all over the world and the negative aspects of biogas production are also presented here. The paper provides information allowing the estimation of the opportunity of building biogas plants and the application of biogas, with special attention to the technical, economic and legal aspects.