The world’s first in-flight study on the use of 100% sustainable aviation fuel (SAF) in both engines of a commercial aircraft has revealed promising results. The study showed a reduction in soot particles and the formation of contrail ice crystals compared to the use of conventional Jet A-1 fuel.
The ECLIF3 study, a collaborative effort between Airbus, Rolls-Royce, the German Aerospace Center (DLR), and SAF producer Neste, was groundbreaking. It was the first to measure the emissions impact of using 100% SAF in both engines of an Airbus A350, powered by Rolls-Royce Trent XWB engines. The study was closely monitored by a DLR chase plane.
The findings were remarkable. The number of contrail ice crystals per mass of unblended SAF consumed was reduced by 56% compared to Jet A-1 fuel. This reduction has the potential to significantly diminish the climate-warming effect of contrails. DLR conducted global climate model simulations to estimate the change in Earth’s atmospheric energy balance, known as radiative forcing, due to contrails. The simulations indicated that contrails’ impact could be reduced by at least 26% with 100% SAF use compared to contrails from Jet A-1 fuel.
These results suggest that using SAF in flight can significantly lessen aviation’s climate impact by reducing non-CO2 effects, such as contrails, alongside reducing CO2 emissions over the lifecycle of SAF.
Markus Fischer, DLR Divisional Board Member for Aeronautics, highlighted the significance of the findings. He stated, “The results from the ECLIF3 flight experiments show how the use of 100 percent SAF can help us to significantly reduce the climate-warming effect of contrails, in addition to lowering the carbon footprint of flying – a clear sign of the effectiveness of SAF towards climate-compatible aviation.”
Mark Bentall, head of Research & Technology Programme at Airbus, emphasised the broader implications: “We already knew that sustainable aviation fuels could reduce the carbon footprint of aviation. Thanks to ECLIF studies, we now know that SAF can also reduce soot emissions and ice particulate formation that we see as contrails. This is a very encouraging result, based on science, which shows just how crucial sustainable aviation fuels are for decarbonising air transport.”
Alexander Kueper, Vice President of Renewable Aviation Business at Neste, pointed out the importance of the study’s findings. He remarked, “SAF is widely recognized as a crucial solution to mitigating the climate impact of the aviation sector, both in the short term as well as the longer term. The results from the ECLIF3 study confirm a significantly lower climate impact when using 100% SAF due to the lack of aromatics in Neste’s SAF used, and provide additional scientific data to support the use of SAF at higher concentrations than currently approved 50%.”
Alan Newby, Director of Research & Technology at Rolls-Royce, underscored the future potential of SAF. He noted, “Using SAF at high blend ratios will form a key part of aviation’s journey to net zero CO2. Not only did these tests show that our Trent XWB-84 engine can run on 100% SAF, but the results also show how additional value can be unlocked from SAF through reducing non-CO2 climate effects as well.”
The research team has published its findings in the Copernicus journal Atmospheric Chemistry & Physics (ACP) as part of a peer-reviewed scientific process. This study provides the first in-situ evidence of the climate impact mitigation potential of using pure, 100% SAF on a commercial aircraft. The ECLIF3 programme, which also includes researchers from the National Research Council of Canada and the University of Manchester, conducted in-flight emissions tests and associated ground tests in 2021.
Avation PLC (LON:AVAP) is a commercial passenger aircraft leasing company owning a fleet of aircraft which it leases to airlines across the world. Avation’s future focus are new technology low CO2 emission aircraft.
