(266b) Life Cycle Assessments of Jet Fuel and Co-Products Made from Lanzatech Biomass-Based Ethanol
LanzaTech has developed a novel method of ethanol (EtOH) production relying on carbon monoxide and hydrogen-containing gas feedstocks. Prior assessments of the LanzaTech process to produce EtOH and chemicals have focused on industrial waste gases (e.g., steel mill exhaust gas), but LanzaTech has expanded their process to biological feedstocks that have been pre-processed via gasification. LanzaTech and PNNL are developing the upgrading of EtOH to infrastructure-compatible jet fuel and other ‘drop-in’ products. This life cycle assessment study investigated the range of potential greenhouse gas emissions for jet fuel and co-products made from biomass feedstocks, including softwood forest biomass, agricultural residues, and switchgrass. The system boundary encompasses greenhouse gas (GHG) emissions from every stage of the fuel life cycle. Materials and energy required at each stage are included, with important assumptions discussed in detail. Biomass gasification and fermentation data comes from LanzaTech, while EtOH upgrading information has been provided by collaborators at Pacific Northwest National Laboratory. Life cycle environmental impacts are assessed in terms of greenhouse gas emissions and fossil energy demand per megajoule (MJ) of fuel product consumed. Biomass feedstocks have different embodied environmental impacts when considering the requirements for harvesting, collection, transportation, and pre-processing, and these differences are evident in the LCA results. Important considerations from this initial life cycle assessment of potential biomass-based LanzaTech operating scenarios will be used to provide guidance about the proper role of this technology in the future alternative fuels marketplace.