The pair signed a memorandum of understanding (MoU) on Wednesday which Rolls-Royce said would help with plans to certify 100% SAF for use in planes.

In the aviation sector, its biggest business, Rolls-Royce plans to make all its commercial engines compatible to run on 100% SAF, which produces up to 70% less carbon than conventional fuel, by 2023.

The challenge for SAFs is that there is a shortage of supply, which the Shell partnership could help address.

Rolls-Royce Chief Technology Officer Paul Stein said in a statement that both companies wanted to decarbonise flying.

"We believe that working together on these aims can deliver benefits for both the development of new innovations as well as collaborating to find ways to unlock the net carbon emissions reduction potential of technology that is already in use today," he said.

(Reporting by Sarah Young; Editing by Kate Holton)