(587ap) Life Cycle Assessments of Lanzatech Biofuels Produced From Biomass Feedstocks
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 is actively researching the compatibility of their process with biological feedstocks that have been pre-processed with gasification techniques. This life cycle assessment study investigated the range of potential greenhouse gas emissions for ethanol and chemical 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, and carbon incorporated into fuel and chemical products was deemed to be carbon neutral as it comes from biogenic material. Materials and energy required at each stage are included, with important assumptions discussed in detail. Life cycle environmental impacts are assessed in terms of greenhouse gas emissions per megajoule (MJ) of EtOH produced and 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. As one additional potential scenario, ethanol upgrading to jet fuel is considered through incorporation of inputs from Pacific Northwest National Laboratory researchers. 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.