Life cycle assessment of lignocellulose-based hydrogen and Fischer-Tropsch diesel in light-duty vehicles

Investigating the sustainability of fuel/propulsion systems for the light-duty vehicle (LDV) fleet requires a life cycle perspective. Lignocellulose-based fuels have potential as domestically produced renewable transportation fuels. This research analyses and compares a number of published life cycle studies, termed well-to-wheel (WTW) for this transport application, with a focus on energy use and greenhouse gas (GHG) emissions for lignocellulose-based alternatives to conventional transportation fuels. Additionally, a pair of unique WTW pathway models was developed in this research. They are based on the conversion of switchgrass (Panicum virgatum), an herbaceous energy crop, to two of the most promising lignocellulose-based fuels: hydrogen and Fischer-Tropsch diesel (FTD). The potential for considerable WTW non-renewable energy use and GHG emissions reductions is clearly demonstrated in this work. While there are a number of challenges that need to be overcome before lignocellulose-based fuels power a significant portion of the LDV fleet, continued research and development into these pathways is warranted.