Biogas is a fuel obtained from organic waste fermentation in an anaerobic digestion plant and can be burned in a cogeneration unit to produce heat and electricity. In Latvia, biogas plants are popular among farmers, as electricity is mostly sold to the centralized electricity grid, receiving a subsidy in the form of a mandatory procurement component. Political circles are discussing the reduction or even abolition of this support, so the question of where to put the produced biogas is topical. Recently, many European countries have incentivized the production of biomethane to be injected into natural gas grids or compressed and used as biofuel in vehicles. The implementation of biogas upgrading unit into an existing anaerobic digestion plant to convert biogas to biomethane (<97%) can be performed by means of various technologies, physical and chemical absorption, adsorption, membrane and cryogenic separation. There are also biological pathway for biogas upgrading - biological conversion of residual CO2 and external hydrogen to methane carried out by hydrogenotrophic methanogens. Aim of this research is to give review about latest developments in technologies and update views of biogas producers on possible upgrading of bio-methane concentration in fermentation process. Main research results have indicated that farmers have interest in technological achievements of biological CO2 reformation, as well as specific changes in fermentation process. They are supporting production of new kind of renewable fuel with possible application for vehicles, also indicate high costs in reformation and mechanical separation processes.