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 PM2.5 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.