This paper presents the economic and ecological effect of Kostkowice Agricultural biogas plant based on a four year study carried out on the prototype installation. Agricultural biogas plant is part of the nature of the research conducted for twenty years at the National Research Institute of Animal PIB Experimental Station. Prof. Mieczyslaw Czaja relates to various aspects of environmental protection. It describes the economic justification for the production of energy from waste biomass (manure, slurry, wastes from feeding table), by the characteristics of substrates and products. It was found that agricultural biogas plant in rural areas are an important link in energy security, mainly due to the very high availability. Ecological effect is presented as effect of the installation solutions for the reduction of pollution of water, soil and air. Reducing greenhouse gas emissions through the recycling of environmentally harmful by-products of animal production of electricity and thermal energy, which is a substitute for environmentally harmful fossil fuels. The advantage of substances digestate is odorless, which is important both in an effort to improve the work culture in agriculture and improving living conditions in rural communities and it is an indisputable argument for the use of biomass for energy purposes.