Biomethane as an Energy Source

Abstract

Microbe-mediated anaerobic digestion occurs in a wide range of natural and man- made habitats and results in the production of biogas. In order to use biogas as a transport fuel it must undergo a costly conversion to biomethane (>95% methane). Biomethane can replace natural gas as a clean fuel in vehicles and produces fewer harmful emissions than petrol, diesel or LPGin spite of the considerable improvementsmade to these fuels in recent years. In addition to producing lower levels of emissions, biomethane poses fewer environmental hazards than other fuels. In the event of an accident, biomethane dissipates into the atmosphere rather than spilling on to the ground – a major benefit for waterways and wildlife. The main barrier for the use of biomethane as a transport fuel is the requirement for additional infrastructure such as refueling stations. This restriction does not apply to the use of biogas or biomethane in static energy generation such as electricity and heat production and biomethane can be injected directly into natural gas distribution networks. While anaerobic digestion has been extensively utilized in wastewater treatment, industrial-scale application of this technology to solid organic wastes has been less successful, probably due to a number of ill defined and poorly understood parameters that influence the efficiency and robustness of this process.