One of the key pathways that can contribute to net-zero goals is to enhance the use of renewable and sustainable biofuels. However, uncertainties remain owing to critical challenges to selecting the right sustainable biofuels technology most suitable for the longer term. These uncertainties can be partly addressed using a multidisciplinary perspective for scenarios and multicriteria decisionmaking analysis. Multicriteria decision support tools (DSTs) are a powerful means to conduct the comparison of technology pathways at different technology readiness levels (TRLs). For this case study, a multidimensional DST was used to compare two technology pathways: (1) gasification combined with Fischer-Tropsch; and (2) hydrothermal liquefaction (HTL) to produce biofuels. The metrics available in the DST were examined, and five metrics related to evaluating profitability, robustness and capital efficiency as well as socio-economic performance were selected. HTL was found to have a higher yield for renewable gasoline and diesel, largely due to higher economic performance and reduced environmental footprint as compared with the integrated gasification Fischer-Tropsch process. However, the TRL of 8-9 of biomass gasification was higher than that of HTL, which was still at 5-6, reflecting that the gasification process is essentially proven at a pre-commercial scale. Based on sensitivity and scenario analyses, the importance of government support for capital cost and of biofuel price production incentives was identified as critical. From this comparison, HTL emerges as an attractive process for the future because of its outperformance from technical and environmental perspectives, but further demonstration efforts are still needed at the commercial scale.

It is well established that producing sustainable fuels and replacing the fossil-based ones is one of the key solutions to achieving net-zero emissions goals. One of the most advanced commercial-scale pathways to biofuels available today is fast pyrolysis. However, due to the need for a supportive regulatory environment and mitigation strategies for uncertainties related to costs and feedstock quality, fast pyrolysis is not yet being widely implemented. In this case study, three fast pyrolysis technologies with a technology readiness level (TRL) of 6 and above have been compared to distinguish between them and identify the conditions under which they are economically viable. The circulating fluidized bed (CFB), rotating cone (RC), and mechanically assisted fluidized bed (MFB) fast pyrolysis technologies were considered. First, the flow diagram and a mass and energy balance comparison were addressed. It was revealed that the RC configuration has better bio-oil yields because it can handle smaller particles. The MFB configuration has a progressive condensation unit at the end of the process, which produces a nearly dry oil having a higher energy content. Four implementation scenarios were studied. The first was the fast pyrolysis standalone process, where all options had marginal economic attractiveness, and the RC configuration economically outperformed the other two. Integration of a fast pyrolysis plant into a sawmill in the second scenario was found to bring significant improvements in revenues and internal rate of return (IRR). Realization of the full value of bio-oil (the third scenario) brought significantly more revenues for the MFB. Finally, the fourth scenario involved adding a progressive condensation unit, which increased the capital expenditure (CAPEX) by 3%–4% while increasing revenues by 32%–35%. A sensitivity analysis highlighted the importance of financial support towards capital cost and the full valuation of bio-oil for the economic viability of fast pyrolysis processes. Progressive condensation leading to more added-value bio-oil makes the standalone fast pyrolysis process more profitable.