Potential CO2 savings through biomethane generation from municipal waste biogas

An alternative source of methane that can also reduce the greenhouse gas effect is one that comes from the upgrading of biogas. This paper studies eight technologies through life cycle assessment (LCA). Six of the technologies are ones that are already on the market and the two others are novel technologies that use carbon mineralization to store CO2 upon their removal. The two novel technologies include alkaline with regeneration (AwR) and bottom ash upgrading (BABIU). These technologies use waste rich in calcium, from municipal solid waste incinerators (MSWI), to store the CO2 from biogas. Among all conventional technologies, high pressure water scrubbing and chemical scrubbing with amine had the lowest CO2 impacts. Of the novel technologies BABIU saves 10% more CO2 than AwR. An uncertainty analysis and a material flow analysis demonstrated that proximity to a MSWI is an important factor to consider. As well, it was seen that while the technology is promising it cannot be applied to an entire country if the proper infrastructure is not in place.