Harmonized algal biofuel life cycle assessment studies enable direct process train comparison

The conclusions from life cycle assessment of algal biofuels (e.g., biodiesel, renewable diesel) vary significantly due to both modeling and inherent technological uncertainties. The inherent uncertainties of US-based algal biofuels production were investigated by eliminating modeling uncertainty via comprehensive harmonization through a meta-analysis. Following harmonization, the cumulative fossil energy consumption (MJ/MJ), global warming potential (g CO2-eq/MJ) and water consumption (m3/MJ) of different algal biofuel process trains were investigated through a stochastic life cycle model. By focusing on the inherent differences of current technologies, this study identified (1) the differences in impact results between different process trains (i.e., different combinations of technology choices along the fuel production life cycle), (2) high impact hotspots, and (3) possible low impact process trains, all of which are crucial to further improve the sustainability of algal biofuels.