The most viable pathway for sustainable biogas utilization in small and large-scale biogas plants were, in tri-generation(CHP þ cooling) and purification and upgrading biogas to biomethane coupled with small-scale CHP unit, respectively. In the case of biogas utilization pathways involving small-scale plants, overall environmental performance could be improved by almost 200% by external heat utilization from the coupling CHP unit and tri-generation, due to enhanced combined electricity and thermal conversion efficiency. The results from this investigation indicated that biogas utilization with fuel cell technology is viable both with respect to energy balance and environmental impacts.