In recent years, anaerobic fermentation technology has attracted increasing interest among farmers. This is not surprising as biogas technologies help to solve problems in ecology, energy and agrochemistry. Biomethane obtained from fermentation of bio-waste can be converted into electricity and heat, as well as biosludge, a high-quality environmentally friendly fertilizer. It would seem that there are only advantages, but most farmers still have doubts about the profitability and feasibility of building biogas plants. For answers to this and other questions, we addressed an expert in this field - CEO of the German company IBBK, which has been providing consulting and training services in the field of biogas for 20 years, Michael Köttner.