Jefferies: Some Sustainable Aviation Fuels Are Greener Than Others
Report shows the amount of lifecycle CO2 emissions savings can vary greatly
While all sustainable aviation fuel (SAF) must be certified to meet the same standards as conventional jet fuel, given the wide variety of feedstocks and approved production pathways, getting to that end product involves varying degrees of lifecycle CO2 emissions. Those produced via the Fischer-Tropsch process tend to have the potential for the highest lifecycle reductions compared with fossil-based jet-A. © Curt Epstein/AIN

A recent report from investment analyst Jefferies shows that not all sustainable aviation fuels (SAF) are the same in terms of its environmental benefits, which can vary significantly depending on which of 11 approved pathways is used to produce them.

Jefferies based its findings on a discussion it hosted with International Air Transport Association (IATA) SAF specialist Daniel Bloch on policy approaches for increasing SAF production and availability. With a wide variety of feedstocks available, some production pathways—and the feedstocks they use—offer significantly better CO2 reduction in their lifecycles, Bloch noted.

For example, using new vegetable oil (as opposed to used cooking oil) as a feedstock for the HEFA process provides only up to a 20 percent savings in carbon emissions compared to Fischer-Tropsch-derived SAF from CO2 and hydrogen using renewable energy, which could bring that number to near 100 percent savings.

Most existing SAF production refineries are using the HEFA process. The report pointed out that while new projects using alcohol-to-jet (ATJ) and Fischer-Tropsch pathways have higher initial capital costs, their operational costs are lower. As a result, production facilities based on those technologies will take longer to achieve scale production. However, according to IATA, these are key to generating increasing volumes of SAF because their third-generation feedstocks are less constrained.

SAF will play a large role in IATA’s goal of net-zero emissions by 2050 and is predicted to provide 65 percent of the overall emission reduction equation. The organization notes that the supply of the fuel will be heavily region-specific, and it is currently not scaled sufficiently to be cost-competitive with conventional jet-A. Bloch sees 2025 as a potential turning point in SAF production, with European policy measures such as the UK SAF blending mandate and ReFuel EU set to commence.