Anthropogenic CO2 as a feedstock for the production of algal‐based biofuels

Biofuels have great potential as low-carbon transportation fuel alternatives and can be essentially drop-in fuels for existing fossil-fuel-based transportation infrastructures. Thus, the incentives for biofuel development are large but there are a number of issues: competition with food, land use, fresh water use, economics in comparison to fossil fuels, and achievable reduction in carbon footprint in comparison to other transportation fuel options. This paper focuses on utilization of anthropogenic CO2 from power plants in advanced biofuel production systems and the integration of those systems with various power plant designs. In doing so, the boundary of the life cycle analysis is expanded to include the power plant CO2 source, considering specifically natural gas, pulverized coal, supercritical coal, and IGCC (integrated gasification combined cycle) options. The carbon footprints for the integrated systems are compared to CCS (carbon capture and sequestration) as well as the current status quo of CO2 release to the atmosphere. The integrated biorefinery-power plant options considered here are shown to be greatly advantaged compared to the status quo (no CO2 capture) carbon footprint, and also advantaged with respect to CCS as long as the biorefinery alone operates with a carbon footprint that is 75% or more lower than that of gasoline. In addition, the projected carbon footprint values, and estimated production costs, for algal-based ethanol are favorable compared to other transportation fuel options including corn-based ethanol and electricity. © 2014 Society of Chemical Industry and John Wiley & Sons, Ltd