Life Cycle Assessment of a Brown Seaweed-based Third-generation Biorefinery Process

The use of seaweed biomass to produce biofuels appears to be a promising process to supplement and secure energy supply and reduce the dependence on fossil fuels. A consequential life cycle assessment (LCA) of a brown seaweed-based-third generation was performed in Nordic conditions to document and improve the sustainability of the process. Three scenarios were considered for the brown seaweed Laminaria digitata: scenario1: S1-BioGas, scenario 2: S2-BioEtOH + BioGas, and scenario 3: S3-NaALG + BioGas. Potential environmental impact categories under investigation were Global Warming, Acidification and Terrestrial Eutrophication. Scenario 1 showed better perfomance compared to other two scenarios for all impact categories, partly because of the energy intensive bioethanol and alginate downstrean separation and purification process, respectively. For improved environmental perfomance of scenarios 2 and 3, focus should be on optimization of bioethanol and alginate downstream processing, respectively.