Fossil fuels currently comprise 80%

Fossil fuels currently comprise 80% of global primary energy consumption, 58% of which is consumed by the transport sector alone [1]. Bio fuels are renewable alternatives and, owing to their origins in natural bio resources, they are geographically more evenly distributed than fossil fuels. Bio gas (approximately 60% methane (CH4), 40% carbon
dioxide (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 bio gas is cleaned and upgraded in order to increase the energy content, the resulting bio methane can be used as a renewable substitute for natural gas. By the end of 2012, 221 bio gas upgrading plants were in operation worldwide, of which 55 units were located in Sweden. Water scrubbing, pressure swing adsorption and chemical scrubbing are the choice of technology in 90% of these plants [2]. The bio methane is uploaded to the natural gas grid or directly compressed to CBG (compressed biogas) for vehicle use.