HEFA-to-Jet: Are We Heading in the Right Direction for Sustainable Aviation Fuel Production?

Hydrotreated ester and fatty acids to jet (HEFA-tJ) is presently the most developed and economically attractive pathway to produce sustainable aviation fuel (SAF). However, an ongoing systematic study of the critical variables of different pathways to SAF has revealed significantly lower GHG reduction potential for the HEFA-tJ pathway compared to competing markets using the same resources for road diesel production. Moderate yield variations between air and road pathways lead to several hundred thousand tons less GHG reduction by project, which is generally not evaluated thoroughly in standard environmental assessments. We also demonstrate that if the HEFA-tJ market has attractive features that biodiesel/renewable diesel does not have, market attractiveness is temporary and will lead to considerable viability risks as HEFA-tJ fuel market integration rises. The negative environmental impact of palm oil production, the primary resource for road production, could also be reduced if methane capture technologies were applied more widely. We emphasize the need for more transparent data and effort in this regard before envisaging rising drastically HEFA-tJ production. Overall, reducing road diesel carbon intensity appears to be less capital-intensive, risky, and several times more efficient in reducing GHG emissions.