Renewable biogas from anaerobic digestion of biomass: influence factors in life cycle assessment

Abstract

Based on the current generation rate of 1 kg-1 person-1, the production of organic waste in Malaysia is estimated to reach 9 metric tons per year by the year 2020. Components of these wastes, however, can be used to generate biogas, not only to decrease waste-related issues, but also to produce renewable energy. There is a growing interest in resource recovery and waste/energy integration through biogas generation from organic waste through anaerobic digestion method. However, due to the anaerobic digestion process varies in different facilities, thus proactive assessment on the status of biogas production and its effect on the environment through life cycle assessment is vital. The objective of this review is to assess factors that affect environmental performance results such as the system boundaries setting, the databases used and the life cycle impact assessment methods applied. This review underscores the fact that goal definition and scope, functional units, system boundaries setting, characterization and life cycle impact assessment methodology, as well as types of software and databases used influence and affects the life cycle assessment results. It suggests that for future cross study comparisons, all assessment guidelines should be addressed to avoid biased comparisons on climate performance between different alternatives.