The BMF HAASE Biogas-Upgrader refines biogas to biomethane by organic-physical scrubbing. This particularly efficient method is characterized by low methane emissions and low power consumption. The BMF HAASE Biogas-Upgrader displays a positive heat balance and upgrades biogas without any heat loss. The required process heat is produced by the system itself even using the low methane slip which is returned into the process. The only external interface on top of the biogas inlet is the electrical connection.