Abstract
This study evaluates multiple biorefinery pathways for the production of liquid biofuels. Feedstocks considered include vegetable oils, lignocellulosic residues and wastes, and dedicated energy crops. Conversion schemes analyzed comprise technologies with high Technology Readiness Level (=7) and scalable to commercial production: thermochemical routes followed by syngas synthesis for methanol; production of bioliquids via thermal liquefaction such as pyrolysis or hydrothermal liquefaction; bioethanol and transesterification or hydrogenation of vegetable oils/used cooking oils. Performance indicators include mass and carbon yields, energy conversion efficiencies, production costs expressed and environmental impact metrics such as CO2-equivalent emissions. The results quantitatively compare the techno-economic and environmental performance of the examined pathways, identifying feedstock type, plant scale, and integration conditions that boost competitiveness. Feedstock emerges as the key factor, influenced by energy density and water content, with vegetable-oil routes leading in drop-in biofuel production, energy efficiency, and carbon yield (>80%). Methanol and biocrude/pyro-oil pathways show promise using residues without hydrogen, achieving <30 kgCO2/GJ and <50 €/GJ. These evaluations are intended to inform the feasibility assessment of an innovative sustainable mobility system, the Off-Board Hybrid, consisting of a liquid-biofuel-fired electric generator operating in island mode and coupled to electric vehicle charging stations.
