A techno-economic and life cycle assessment of a new power and biomass to liquids (PBtL) configuration with negative emissions for producing sustainable aviation fuel (SAF)

A novel configuration of the hybrid Power-and-Biomass to Liquids (PBtL) pathway for producing sustainable aviation fuels (SAF) has been developed and assessed from a techno-economic and environmental perspective. The proposed configuration can achieve negative emissions and hence a new bioenergy with carbon capture and storage (BECCS) route is proposed.

The amount of CO2 that is captured within the process and that is sent for storage ranges from 0 % to 100 %, defining the various PBtL-CCS scenarios that are evaluated. Mass and energy balances have been established through process modelling in Aspen Plus and validated using data available in the literature. Further, the System Advisor Model (SAM) tool was used to model a dedicated offshore wind farm, based on location specific wind data. Results from the technical assessment have set the foundation for economic and environmental evaluations. The economic evaluation of the proposed SAF production configurations estimates minimum jet fuel selling prices (MJSP) ranging from 0.0651 to 0.0673 £/MJ, mainly driven by electricity consumption and feedstock cost. Costs for CO2 compression, transport, and storage have a small contribution to the MJSPs of all the proposed scenarios. Global warming potentials range from −105.33 to 13.93 gCO2eq/MJ, with PBtL-CCS scenarios offering negative emissions and aligning with the aviation industry’s net-zero ambition for 2050. Water footprints range from 0.52 to 0.40 l/MJ, mainly driven by the water requirements of the alkaline electrolyser and refinery, followed by the wind electricity water footprint. Based on the outputs of the assessments, the resulting SAF could benefit of the support proposed by the UK SAF mandate, which could boost their economic performance by awarding certificates with monetary value. Estimates indicate that the cost of certificates that breakeven the fossil jet fuel price could reduce if negative emissions are also rewarded under this scheme.

Overall, the study introduces for the first time and assesses a novel net-negative SAF configuration, and the new information generated provides meaningful insights to a variety of stakeholders such as process developers, academics and policy makers.