Techno-Economic Analysis and Life-Cycle Analysis of Two Light-Duty Bioblendstocks: Isobutanol and Aromatic-Rich Hydrocarbons

Isobutanol and aromatic-rich hydrocarbons (ARHC) are two biomass-derived high-octane blendstocks that could be blended with petroleum gasoline for use in optimized spark-ignition engines in light-duty vehicles, potentially increasing engine efficiency. To evaluate technology readiness, economic viability, and environmental impacts of these technologies, we use detailed techno-economic analysis (TEA) and life-cycle analysis (LCA). We assumed isobutanol is produced via biochemical conversion of an herbaceous feedstock blend while ARHC is produced via thermochemical conversion of a woody feedstock blend. The minimum estimated fuel selling price (MFSP) of isobutanol ranged from $5.57/gasoline gallon equivalent (GGE) ($0.045/MJ) based on today’s technology to $4.22/GGE ($0.034/MJ) with technology advancements. The MFSP of ARHC could decline from $5.20/GGE ($0.042/MJ) based on today’s technology to $4.20/GGE ($0.034/MJ) as technology improves. Both isobutanol and ARHC offer about 73% greenhouse gas (GHG) emission reduction relative to petroleum gasoline per LCA of these two bioblendstocks. On the other hand, water consumption in the production of both bioblendstocks exceeds that of conventional gasoline although process engineering offers routes to cutting water consumption. Over their life-cycles, both isobutanol and ARHC emit more NO_x and PM_2.5 than petroleum gasoline. Improving the energy efficiency and lowering air emissions from agricultural equipment will reduce the life-cycle air pollutant emissions of these bioblendstocks.