Europe’s ambitious targets to replace increasing quantities of fossil kerosene with green aviation fuels will be extremely challenging to meet – though with a broad and evolving mix of fuel sources, as well as sustained political and industry support, it is within grasp.
This is the conclusion of Dr Stephen Dooley, an associate professor at Trinity College Dublin and an expert in sustainable aviation fuels (SAF). Dooley oversees the Ryanair Sustainable Aviation Research Centre, which is hosted by the university.
In an interview with Euractiv, Dooley said the EU’s decision to rapidly replace fossil fuels with more environmentally friendly liquid fuels was akin to setting off on a voyage into the unknown.
“You’re going to get on a boat and for the first time sail around the world. Are you confident? Well, you don’t have any basis to be confident. But what you can say is that it’s possible. You prepared well. You’ve taken it seriously. You’re committed to it,” he said. “That’s where we are.”
“We’re setting off on a grand expedition here – even without the basic information needed to say which direction we should go or how we should do it, but we’ve agreed that we’re going to try to do it – now, we have to figure out exactly how we go about it.”
Under the ReFuelEU aviation mandate, every plane departing from an EU airport must partially run on green jet fuel from 2025. The percentage of SAF blended with kerosene will start at 2% by 2025, moving to 6% by 2030, 20% by 2035, 34% by 2040, and reaching 70% by 2050.
But despite the legal targets, it remains unclear whether Europe has the production capacity to ensure the bloc can supply airports with sufficient quantities of green fuel.
Boosting production
It is estimated there is a need for 300 biorefineries to meet the targets in addition to the 69 conventional refineries processing biofuels. Currently, there are plans in Europe for about 30 biorefineries.
In 2022, the volume of SAF produced was 127 million litres, while in 2023 there are purchase agreements for around 434 million litres (however, Dooley cautions that reliable figures are difficult to obtain at the moment). Although the increase is significant, this still represents less than 1% of the fuel used in aviation globally.
“We haven’t done the work to realise what quantity of feedstock would be available in Europe. What types of biological feedstock, such as plant matter, do we need? How much can we get? Where and what type? What processing technology does that need to be configured with? We need to do that work,” he said.
“It’s too early to say that [the SAF targets] can’t be met, and I believe we will go a long way to meeting them. And the difference between those two things – ‘go a long way’ and ‘meeting them’ – will be on the basis of information.”
“And we don’t have that information at the moment. We have to go and get it,” he added.
E-fuels vs biofuels?
Green campaigners have pushed for the ramp of e-kerosene, arguing it is the only truly scalable solution. They have generally championed e-kerosene made with green hydrogen and carbon from the atmosphere as a cleaner option than biofuels, which they say run sustainability risks if over-incentivised.
But Dooley cautioned that the amount of renewable energy required to make e-fuels means that they are likely to remain in very short supply for time to come, making advanced biofuels from wastes and residues a necessity to meet SAF targets.
Asked if there should be a focus on e-fuels or biofuels, Dooley took a broader position. “I think the real answer to your question is that we need all comers,” he said. “My answer here, everywhere, is: It’s about details.”
“What we need are e-fuels and biofuels, not one or the other. Crucially, we need both type of fuels to be made, and made in a way that maximises the CO2 savings each offer.”
Policymakers excluded crop-based biofuels from ReFuelEU’s SAF mandates citing sustainability concerns. But according to Dooley, the sustainability of each biofuel should be assessed individually, as the feedstock used and the production process can greatly influence the carbon savings inherent in the fuel.
“The EU has made a sweeping rule that [crop] feedstock leads to land use change, therefore, those feedstocks must not be allowed to produce fuel. It’s a pretty broad brush, pretty crude metrics,” he said. “Rather, we need to put the magnifying glass onto each process.”
Fraud concerns
In practice, most of Europe’s SAF in the coming years is expected to be met from biofuels derived from leftover frying oil.
While a green option, the waste biofuels industry has been rocked by fraud scandals, with allegations that frying oil imported from abroad contains virgin palm oil – a restricted feedstock in the EU.
In August, the European Commission launched an investigation into used cooking oil biofuels being imported from China and the UK.
Dooley believes that although strong monitoring processes should be in place, the issue is likely to be mitigated as reliance on one feedstock falls.
“Coming into 2030 we’re going to have other SAFs that are being produced at a larger volume than those used-cooking oil-derived SAFs,” he said.
Critics of the aviation industry have also alleged that as the number of flights grows, the SAF targets will be increasingly difficult to meet.
Asked about whether predicted growth in aviation levels is likely to see the EU miss its SAF targets, Dooley said that the situation is not clear enough to give a definitive answer.
“We don’t know that we can do that. But we don’t know that we can’t do it,” he said.
“It’s going to be a lot of work,” he added. “And we’re working as hard as we can.”
[Edited by Nathalie Weatherald]
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