The topic discussed in this article includes the profitability of investing in agricultural biogas plant, it also presents opportunities and threats of biogas sector. Payback period of building the biogas plant, according to its power output, was estimated, taking into account cost of a plant, operational costs and components’ costs, as compared with the profits from selling the electricity, its certificates of origin and heat. It was stated that return on investment raises with rise of plant power output. Low profitability is investors’ main concern - it takes many years for the Investment costs’payback.