When a Virgin Atlantic Boeing 787-9 flew from London to New York in late November with both its Rolls-Royce Trent 1000 engines powered purely by sustainable aviation fuel, the event was celebrated as a major milestone on aviation’s journey to net zero carbon emissions.
But while it showcased how far aviation has come on its journey to reduce harmful emissions, flight VS100 also illustrated how far the sector still has to go.
Although it demonstrated decarbonisation and industrial collaboration, Virgin’s solely-SAF flight was a high-profile lobbying initiative to illuminate the lack of sufficient and aligned government policies to support non-fossil fuels for aviation.
“There’s simply not enough SAF,” declared the airline’s chief executive, Shai Weiss, highlighting less what had just been historically achieved and more on why 100% fossil-free flights will not be routinely replicated any time soon.
“It’s clear that in order to reach production at scale, we need to see significantly more investment,” said Weiss. “This will only happen when regulatory certainty and price support mechanisms, backed by government, are in place.”
One week later, IATA director general Willie Walsh declared that SAF, as a proportion of all renewable fuel production, would grow from 3% this year to 6% in 2024 – but added that to reach net zero carbon by 2050, “aviation needs between 25% and 30% of renewable fuel production capacity for SAF.”
Robert Thomson, aerospace partner of the global management consultancy Roland Berger, goes further, asking: “When we talk about net zero, what do we really mean? Net zero carbon? Or net zero impact of aviation on the climate?
“Carbon is one thing,” he explains. “But putting contrails, NOx (nitrous oxides), and carbon together you perhaps get two-to-three times the impact of aircraft on the environment than with carbon alone.”
Thomson spotlights what is rapidly becoming aviation’s next big eco-issue – the additional damage done by non-CO2 emissions, a key focus of flight VS100.
Fossil-based jet fuels contain aromatics, naturally occurring elements which serve as vital seals to prevent fuel leakage inside engines.
Because aromatics burn more slowly than other elements of fuel, soot particles are expelled into the atmosphere.
In specific conditions water vapour freezes around the particles forming contrails, or vapour canopies which trap heat in the air, exacerbating aviation’s warming effects. SAF will help reduce these.
On flight VS100, 88% of the fuel was derived from recycled waste fats and oils, while sustainable aromatic kerosene, or SAK, comprised the remaining 12%, performing the sealing role of aromatics.
Air BP provided the SAF while the SAK came from Virent, part of Marathon Petroleum, enabling Virgin and Rolls-Royce to demonstrate how 100% non-fossil fuel could safely and more cleanly power large, long-range aircraft.
Airframe and engine manufacturers are targeting 2030 for approval of 100% SAF for commercial passenger aircraft and have proved or are working to test the new fuel, which is twice the currently approved maximum blend of 50/50 SAF/fossil fuels.
Other SAF 100 tests have also occurred including a Gulfstream corporate jet a week before VS100, Boeing-NASA tests with a Boeing 737 Max, and in one of the four engines of an Emirates A380 around the time its home city, Dubai, hosted the UN’s COP28 climate summit.
But who’ll fly with 100% SAF? Many of the airlines adopting it are committing to a maximum 10% by 2030, while others are targeting even less. And there are widespread concerns that there won’t be enough to meet those targets.
Along with air navigation reform, new aircraft and engines, and more SAF production pathways, Roland Berger says the industry “should agree that non-CO2 emissions are a major part of aviation’s climate footprint and align on a standardised approach.”
Flight VS100 was a step in the right direction.
But with pressure intensifying to further reduce emissions, it’s still too early to celebrate.
