In addition to the environmental problems of fossil fuels, as precursors of global warming in their combustion, another important aspect is the dependence on other countries with, at times, political instability. Thus, the production of biomethane is proposed as a viable alternative with a much lower carbon footprint than natural gas and reducing dependency, since it could be obtained in our country. It also has an additional advantage, existing facilities can be used directly, which is not the case with other renewables.
In this article*, three ways of obtaining biomethane from different biomasses are studied: (i) fermentation of manure and its subsequent upgrading by eliminating CO2, (ii) fermentation of manure and methanization of biogas using renewable hydrogen from electrolysis, and (iii) biomass gasification with oxygen and methanization of the resulting gas. The processes were simulated and environmental and economic life cycle analyses were carried out. From the point of view of efficiency and economics, the fermentation and CO2 capture technology showed the best results (66.80% and € 19.2/GJ). From the environmental point of view, the system with the best environmental performance varied depending on the impact category analyzed, being the system with biomass gasification and methanization the one that showed the best results overall.
(*) Skorek-Osikowska, A.; Martín-Gamboa, M.; Dufour, J. “Thermodynamic, economic and environmental assessment of renewable natural gas production systems”. Energy Conversion & Management: X, 2020, 7, art. no. 100046. https://doi.org/10.1016/j.ecmx.2020.100046
More information: Javier Dufour, Research Professor, Systems Analysis Unit. firstname.lastname@example.org