Techno-Economic Assessment and Life Cycle Assessment of CO2 to Biofuel via Micro-Algae Process

Abstract

The goal of the work is to assess economic and environmental performance of microalgal biofuel production chain and identify hotspots in terms of CAPEX/OPEX, GHG emissions, energy demand and other environmental impacts. These evaluations are used to assist future R&D and business development directions. The modelled plant has a production capacity of 163 kt-biofuels/year (corresponding to 1 Mta-CO2/year treatment capacity by microalgae). Operational energy demand is around 0.17 MJ/MJ of biofuel. Techno-economic assessment shows that future biofuel production cost would be down to 1190 €/t. It is suggested to focus future R&D on cultivation, HTL and upgrading operations, as well as equipment design of cultivation. Life cycle assessment shows that a GHG emissions reduction of 72% would be reached by micro-algae biofuel, compared to conventional fuel in French electricity mix scenario. When looking into all environmental impacts, there is a trade-off when switching to microalgae-based biofuel, and trade-off seems acceptable. It is suggested to focus future R&D on heat integration of HTL/upgrading, reduction of nutrients and flocculent or research of alternative chemicals with lower environmental impact. Use of affordable blue or green hydrogen would further reduce environmental impacts as well.