Fossil fuels currently comprise 80% of global primary energy con- sumption, 58% of which is consumed by the transport sector alone [1]. Biofuels are renewable alternatives and, owing to their origins in natural bioresources, they are geographically more evenly distributed than fossil fuels. Biogas (approximately 60% methane (CH4), 40% carbon di- oxide (CO2) and some trace gases) produced during anaerobic digestion of organic matter (organic waste, sewage, manure etc.) is a renewable energy carrier, which can be used for e.g. combined heat and power (CHP) production. However, if biogas is cleaned and upgraded in order to increase the energy content, the resulting biomethane can be used as a renewable substitute for natural gas. By the end of 2012, 221 biogas upgrading plants were in operation worldwide, of which 55 units were located in Sweden. Water scrubbing, pressure swing adsorp- tion and chemical scrubbing are the choice of technology in 90% of these plants [2]. The biomethane is uploaded to the natural gas grid or directly compressed to CBG (compressed biogas) for vehicle use.