The aim of research was to determine the ecological effect of the energy production in the agricultural biogas plant in Kostkowice by calculating CO2 and other greenhouse gases balance in a production process, comparing the quantity of greenhouse gases (CO2, SO2, NOx) produced in the combustion process of hard bituminous coal and biogas; of exploiting heat of the cogeneration as substitute of the natural gas in heating of animal’s houses; of reduction of the greenhouse gas emission from liquid and solid manures. It appears from collected data that the total CO2 emissions reduction gained above 4 000 tons what almost ¾ constituted methane from liquid and solid manures. Utilisation of all produced products (electric energy, heat, digestat) of biogas plant with the cogeneration is an argument for the propagation of the development of this direction which gives the possibility of reducing the greenhouse effect, also caused by an agricultural production. For the development of energetics based on biomass, such regulations which give to investors the guarantee of the assumed profitability are of great importance. The lack of stability expose and discourage for using this essential renewable energy source.