(565j) Well to Wake Analysis of Switchgrass to Butanol via Co-Fermentation of Sugar and Gas with Subsequent Conversion to Jet Fuel

Increasing demand for jet fuels requires sustainable aviation fuels that also reduce the environmental impact caused by conventional fuels produced from crude oil. Co-fermentation of sugar and gas is a novel technology for the production of alcohols like n-butanol and ethanol from various feedstock’s. Co-fermentation of sugar and gas from the same amount of feedstock has the potential to increase alcohol yield by over 20%. Lignocellulosic biomass like switchgrass provides a renewable source of carbon to produce n-butanol via the co-fermentation process. Switchgrass butanol can be further converted to jet fuels with potentially lower environmental impacts than conventional jet fuels. To evaluate the environmental impact of jet fuel made from switchgrass, life cycle assessment was performed on the co-fermentation to account for life cycle greenhouse gas emissions from all inputs in the production process. In the current study, LCA is done from well-to-wake, i.e. including both production and combustion of jet fuel based on data taken from Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET) model. Emissions from co-products are also allocated in the LCA to properly account the life cycle greenhouse gas emissions from switchgrass jet fuel. LCA results are presented on the basis of 100-year global warming potential (GWP) per unit energy. Results from LCA of jet fuels made from switchgrass butanol are compared with corn-to-Jet pathway and conventional Jet fuel from crude oil refining. GWP 100 will provide important insights into the feasibility and benefits of the new co-fermentation process of switchgrass to jet fuel. Jet fuel from switchgrass has 54% and 62% lower GWP 100 compared to corn jet and conventional Jet fuel, respectively. These results demonstrate that switchgrass and co-fermentation technology can play a key role in reducing GHG emissions and increasing yields.