Luke Ervine, Virgin’s head of sustainability, agrees, pointing to SAF’s role as a “drop-in solution”, one that can be utilised as airlines do conventional jet fuel without requiring costly and time-consuming engine modifications.

"To be able to fill up with 100% SAF and really showcase the ability of that particular fuel, and to act as a drop-in solution without having to modify engines or change any of the fuel infrastructure, is key," he explains. "We need something that is a replacement for fossil. It’s not the silver bullet, but it is a seminal moment."

Ervine continues: “As well as greenhouse gas reductions, there’s also non-CO2 reductions. We’ve got SAF onboard that, if you look at the particulate emissions – and we’ve also done some lab tests as well – and compare them to fossil, there’s about 60% to 70% fewer particulate emissions."

But professor Alastair Blanshard, director and sustainable aviation lead at consultancy ICF, flags to the need for all potential emission-reducing technologies to be embraced and supported in aviation's journey to decarbonisation.

"It’s important that SAF, hydrogen or electric are not seen to be competing with each other," says Blanshard. "You actually need a lot of hydrogen to make SAF. Developing hydrogen makes more SAF and vice versa so they’re supporting each other.”

Supply and demand

The long-term security of SAF production, and the support required from government to kick start it, is something Virgin Atlantic, and others, has touted as a potential barrier – and that's putting it mildly.

"VS100 was always about proving from a technical perspective there is no barriers," says Ervine. "The big challenge for us is the availability and price of fuel, and making sure from a value chain perspective we’re getting the government to help us with policy to look at things like giving investors the assurance they need.

"There’s always going to be an additional cost, but the quicker you can scale an industry, the more cost-efficient it becomes. We’re working with our corporate partners to help spread that cost. The scaling will help bring the cost down, but it will be higher in the short-term.”

Virgin Atlantic has secured an offtake contract – an arrangement between a producer and a buyer to purchase or sell portions of the producer's upcoming goods – with Gevo for 10 million US gallons of SAF over a seven-year period through its partner and minority shareholder Delta.

The airline also carries out spot offtakes, but Ervine stresses “there is so little of this [SAF] available so we’ve had a couple of years where we’ve taken very small amounts into Heathrow". He does, however, reveal Virgin Atlantic has some memorandums of understanding with "some interesting partners to signal intent”.

Blanshard, though, points to the disparity between mandating SAF consumption in aviation and certainty of investment. “A mandate tells me you have to buy something, but it doesn’t tell me how much you have to pay for it, and that’s a really important distinction," he cautions.

"There’s a lot of risk around not only someone buying it, but paying a good price for it. It’s not money that’s the most useful thing for government, it’s certainty."

Progress, not perfection

Blanshard and his team are responsible for completing a groundbreaking end-to-end lifecycle analysis of Flight 100. The assessment will seek to account for all emissions associated with the flight, primarily those within Virgin Atlantic’s control, such as in-flight catering and waste.

"When you look across the supply chain, a lot of the data is not connected – the catering and waste management," he says. "There’s an element of saying, we need drive that focus on emissions all the way up the supply chain to get a better understanding of where those emissions are coming from.”

He is enthusiastic about the "exciting" challenges around SAF production and pricing. "“Go back a decade and the challenge was, 'is it safe?'," he reasons. "It’s taken two decades of work to get to this point. That’s a really big win.”

Addressing the sceptics, he asserts: "We’re trying to reduce emissions, and we have a choice here between progress and perfection. We can go for the perfect solution, but it will be expensive and difficult to scale. We’ll be doing something at such a small scale and at such a high price that we’ll just have very little impact.

"No one is sitting here saying, let’s use cooking oil forever. It’s a finite resource, but the one we’ve got today, so we need to make the best use of what we’ve got."