NASA: SAF reduces contrails by up to 70%

Using a 1:1 blend of sustainable aviation fuel (SAF) can result in an up to 70% reduction in contrail formation at cruising altitude, according to research by NASA and the German Aerospace Centre (DLR).

Contrail cirrus, made up of ice crystals, account for the major share of aviation’s climate impact, said NASA. Yet, the links between jet fuel composition, contrail microphysics and climate impact remain unresolved. Air traffic has increased in the past two decades, resulting in an increase in radiative forcing from contrails by 64% from 2005 to 2018.

The research took in observations from two DLR-NASA aircraft that measured exhaust and contrail characteristics of an Airbus A320 burning either standard jet fuels or low aromatic SAF blends.

The results show that soot particles can regulate the number of ice crystals. This provides experimental evidence that burning low aromatic SAF can result in a 50 to 70% reduction in soot and ice number concentrations and an increase in ice crystal size. Reduced contrail ice numbers cause less energy deposition in the atmosphere and less warming.

The research paper recommends that reductions in aviation’s climate impact could be made through the widespread adoption of low aromatic SAFs, and from regulations to lower the maximum aromatic fuel content.