Globally Resolved Life Cycle and Techno-Economic Assessment of Algal-Based Biofuels

Advanced algal biofuels have the potential to support the decarbonization of hard-to-electrify transportation fleets. However, techno-economic analyses (TEAs) and life cycle assessments (LCAs) of algal biofuels have often focused on locations in suboptimal latitudes for algal cultivation, which can underrepresent the sustainability potential of the technology. This study performs a global TEA and LCA quantifying the regional economic potential and environmental impacts of algae biomass production and conversion to fuels across 6,685 global locations. A dynamic process model serves as the foundation for regionally resolved LCA and TEA to concurrently evaluate the techno-economic viability and environmental impacts of the system. The LCA accounts for the life cycle impacts associated with global electricity, hydrogen, and nutrient supply chains across 10 different environmental impact categories. Similarly, the TEA considers location-specific capital expenses, labor costs, and tax rates. The model predicts optimal annual average areal productivity values between 24.8 – 27.5 g m^-2 day^-1 in equatorial regions. In terms of LCA outputs, the global warming potential (GWP) of the system was found to be the lowest in South America and Central Africa with net emissions ranging between 55 - 70 g CO_2-eq MJ^-1. Although GWP results show to be lower than the petroleum baseline (87 – 97 g CO_2-eq MJ^-1_­), direct land use change emissions restrict algal biomass cultivation in these high-productivity regions. Additional environmental impacts such as respiratory effects and eutrophication potential indicate that algal biofuel production might lead to more detrimental effects than conventional diesel with optimal results ranging between 5 – 25 mg PM_2.5-eq MJ^-1 and 3 – 62 mg N_eq MJ^-1, respectively. Results from the TEA follow productivity trends and favor locations in Central America and Southeast Asia with minimum fuel selling prices ranging between $1.8 – $2.0 per liter of gasoline-equivalent. The presentation will present global maps of results that illustrate visually optimal places for algal production in terms of productivity, economics, and environmental impacts. Discussion will focus on understanding the challenges and opportunities to improve the economic viability and minimize the environmental impacts of algal-based biofuels.