A critical review on life cycle analysis of algae biodiesel: current challenges and future prospects

Life cycle analysis (LCA) of algal biodiesel production process can provide a quantitative measure for its sustainability. In this paper, the published LCA studies of algae biodiesel processes are reviewed, demonstrating there are few comprehensive studies covering the complete process; therefore, outcomes can be inconclusive. The variability in algae type, reactor type and conditions, and other factors will impact LCA outcomes. However, the lack of a systematic framework for LCAs applied to the algae biodiesel process is also a factor in the variable LCA outcomes. Factors such as system boundaries, temporal units, choice of allocation, land use, and biogenic carbon source have to be redefined; and other variables such as infrastructure construction, systematic maintenance, transportation, and waste management need to be considered in the LCA strategy. Critically, the economic burden associated with both upstream and downstream processes should also be included in the LCA approach. Future studies could focus on process design, optimization, and intensification. This review paper offers a comprehensive and critical literature review of the LCA and sustainability assessment for the entire algal biodiesel process, which can benefit relevant future studies.