Biogas Upgrading: Global Warming Potential of Conventional and Innovative Technologies

Biogas upgrading technologies provides an alternative source of methane and their implementation in waste management systems can help reduce the greenhouse effect. This paper uses a life cycle assessment (LCA) to study eight technologies, six of which are already on the market and the two others are novel technologies that use carbon mineralization in their process in order to not only remove CO2 but also store it. The two technologies are under development in the frame of the UPGAS-LOWCO2 LIFE08/ENV/IT/000429 project (upgas.eu) and include alkaline with regeneration (AwR) and bottom ash upgrading (BABIU). These technologies utilize waste from municipal solid waste incinerators rich in calcium to store CO2 from biogas. Among all conventional technologies, high pressure water scrubbing and chemical scrubbing with amine had the lowest CO2 impacts. The results of the two novel technologies show that BABIU saves 10% more CO2 than AwR. An uncertainty analysis and a material flow analysis showed that the placement of these two novel technologies is an important factor (for CO2 emissions and availability of waste) and therefore they should be located close to a MSWI that produces sufficient waste.