Chapter 11 - Life cycle assessment of biomethane technology

Abstract

Globally, anaerobic digestion (AD) technology for biogas production has been widely implemented for various biomass. Investigation on further utilization of biogas into electricity, heat, and biomethane have been highlighted in many studies. Biogas upgrading or biomethane technology, to date, is developed and optimized to provide more effective and efficient separation of CO2 in biogas. This is aiming to increase the methane concentration in biogas, hence higher energy can be resulted from the biomethane utilization (either as fuels or electricity). Life cycle assessment (LCA) study is applied to evaluate the potential damage to human health, ecosystem quality, and resources from the implementation of biomethane technology. This chapter provides viewpoints on different biomethane currently available in the market and investigates the environmental feasibility of converting biogas into biomethane. This chapter describes how to conduct an LCA study, including goal and scope definition, life cycle inventory (LCI), life cycle impact assessment (LCIA), and the interpretation phase. The chapter provides comparison of several dataset and software commonly used in the LCA. Also, this chapter critically evaluates by reviewing relevant literatures in LCA of biomethane technology, emphasizing on all stages in LCA studies. Many studies have reported the end-point and mid-point approach on defining the impact category in LCA of biomethane technology, including human toxicity, climate change or global warming, acidification, and eutrophication. The studies showed that biomethane technology using physical, chemical, or biological approaches offer negative environmental impacts. This indicates that applying biomethane technology for upgrading biogas into biomethane have low impacts on environment, human health, and resources. Hence, scaling up or commercialization is potential, yet further investigation is required with respect to sustainability and circularity aspects.