Rolls-Royce is leading a new project to find smarter ways of using sustainable aviation fuel (SAF) to increase its effectiveness and role in reducing non-CO₂ emissions, specifically those associated with contrail formation.

Co-funded through the Non-CO₂ Programme, part of the ATI Programme, the Quantifying Reduction in Thermal Contrails by Optimising SAF (QRITOS) project brings together Rolls-Royce, British Airways, Imperial College London and Heathrow.

The benefits of SAF for reducing end-to-end CO₂ emissions from fuel are well understood, and SAF is expected to play a key role in aviation’s decarbonisation journey. However, in-flight measurements behind aircraft have also shown SAF’s potential to reduce the number of ice crystals in contrails and therefore the potential climate impact of these thin clouds of ice particles that can form behind aircraft.

The amount of SAF currently available is only a small proportion of aviation’s overall fuel requirements. It is typically mixed with conventional fossil fuel, resulting in wide-scale deployment at very low SAF blend ratios. However, SAF use is expected to increase in the UK with the introduction of the SAF mandate which came into force at the start of the year and will see 10% of SAF in the UK fuel in 2030 and 22% in 2040.

Constantly changing weather means different flights cause contrails at different times and locations, yet most of the potential climate impact comes from only a small proportion of flights. This creates an opportunity for smart SAF use targeting those flights expected to form persistent contrails. The QRITOS project aims to demonstrate the feasibility of this approach, at one of the world’s busiest airports. It will do this by combining data from British Airways flight trials, advanced modelling and satellite observations to monitor contrail formation following this targeted SAF usage.

The project aims to show that we can prioritise particular flights for SAF, focusing on where it can deliver the greatest environmental benefit and maximise the effectiveness of the current levels of supply.

The Non-CO₂ Programme focuses on addressing challenges with reducing non-CO₂ emissions from aircraft, as outlined in the ATI’s Non-CO₂ Technologies Roadmap. The funding programme is delivered by the Aerospace Technology Institute, Department for Business and Trade (DBT) and Innovate UK, in partnership with the Department for Transport (DfT) and the Natural Environment Research Council (NERC).

Industry Minister Chris McDonald said: “This is government and business working together at its best, and I look forward to seeing how this Rolls-Royce project can help keep UK industry at the forefront of the race for sustainable aviation.

“We’re bolstering our support for the aerospace industry through our modern Industrial Strategy – giving business the confidence it needs to invest in UK advanced manufacturing and delivering on growth as part of our Plan for Change.”

Concluding in April 2027, the two-year project will also enhance forecasting methods, advance understanding and modelling of contrail formation, and develop verification methods based on satellite data.

Source: Rolls-Royce