From pilot to policy change: building a sustainable future for flight

When Covid-19 grounded her career, pilot Agnes Thornton turned her focus to sustainable aviation fuel and co-founded aviation consultancy SFS Ireland. In her latest interview, she explains why aviation needs to rethink its reliance on fossil fuels and how microalgae can help.

What's the problem with aviation fuel?

I think it's quite obvious that things can't continue the way they are. The top issue is that aviation fuel is derived from fossil oils and unsustainable by nature, but other issues are availability and the growing need for energy independence. The fossil fuel supply chain is localised to certain geographic regions, whereas a sustainable aviation fuel industry can be designed for specific domestic criteria and have the fuel produced locally.

Why did you set up SFS Ireland?

I'm a pilot, but during Covid-19, when pilots' jobs collapsed, I went back to education and completed a Master's degree in aviation management. My thesis involved a case study on Sustainable Aviation Fuel (SAF) and looked at barriers to implementation, including a case study on Etihad, Abu Dhabi. At the same time, my pilot colleague, Darren Carty, was also working on a postgraduate degree looking at the life cycle analysis of sustainable aviation fuel. We both realised how little awareness there was on anything regarding SAF in Ireland, so we teamed up and founded SFS Ireland in 2021. Change needs to happen, and we're just trying to be a very small part of that change.

Tell us a little about your work at SFS Ireland so far

We first started out on an advocacy route, connecting the researchers we knew with our network of aviation stakeholders: fuel producers, regulators and so on. In a study called Ireland's Sustainable Aviation Fuel Opportunity, we collaborated with SkyNRG, examining SAF feedstock availability in Ireland, exploring the global technological pathways available for the country and what made economic sense. This feasibility study was supported by leasing company Avolon, ORIX Aviation, and aerospace firm Boeing. Our results showed a SAF industry in Ireland could generate revenue of €2.55 billion by 2050 and provide up to 1,000 high-skilled jobs in Ireland, but significant progress was required for Ireland to be able to develop SAF at scale, and policy changes were needed to help accelerate a pathway for SAF production. The results were published by the then Minister for Enterprise, Trade and Employment in Ireland in October 2023. Since 2024 we've been part of an EU-funded project, SusAlgaeFuel, where we provide Life Cycle Assessment, certification support, and policy advisory services.

Have you had a lot of interest in SAF?

There has been, and still is, huge industry interest. A lot of that is genuine interest, but it's also rooted in European legislation. Using SAF is now mandatory. The European Union's ReFuelEU Aviation Regulation has obligated fuel suppliers to blend SAF into the fuel available at all EU airports, rising from 2% in 2025 to 6% SAF by 2030 and then 70% by 2050. Even before mandates, the leasing industry showed a huge interest in SAF. Airlines have also shown a big interest, but financial support from them is often a bigger challenge due to the industry's tight operating margins. Increasing the use of SAF is a big endeavour, spanning from research, to pilot, to commercial scale, and selling the fuel.

What is the state of play of SAF in Ireland?

In Ireland, SAF is very much a work in progress. Ireland has been at the forefront of aviation innovation over the years, and while there wasn't that much awareness, this is changing. Ireland published its first ever SAF Policy Roadmap in August 2025 to decarbonise the aviation sector and meet ReFuelEU Aviation mandates. We're very encouraged to see that this extensive roadmap has been produced, and hopefully it will be actioned.

What about the rest of Europe?

On a European level, we have seen good progress with both the Renewable Energy Directive and ReFuelEU mandates. However, recent assessments [of the ReFuelEU targets] from the European Aviation Safety Agency (EASA) question whether the 2025 2% target has been met, and also forecast a 100-megaton shortfall in SAF use on the 2050 target. EASA says the main constraints are technology roll-out and feedstock availability, and if you ask the airlines and the airports, they say SAF is just very difficult to get your hands on. At the moment, almost all SAF is biofuel made from used cooking oil, a finite feedstock that we will run out of as it can't be grown or scaled quickly enough. Also, more than 90% of used cooking oil is imported into the EU for processing, and that's not sustainable in terms of energy independence. So we need to look at other SAF technologies and pathways, and diversification of feedstock for existing SAF production facilities.

How is the EU project, SusAlgaeFuel, helping?

The project will help to address the predicted shortage of used cooking oil and contribute to the energy independence of countries. Researchers are looking at innovative ways to grow, harvest and process microalgae, that is, to get the oil out of the microalgae for SAF production, and as part of this, SFS Ireland is conducting process simulations and a life cycle analysis to assess the sustainability and scalability of algae fuel production. Microalgae is kind of in its second spring. Originally discarded as it was so expensive to extract the oil, microalgae is making a comeback. We see a lot of EU projects looking at how to utilise microalgae; we're part of a European cluster of ten R&D projects all looking at microalgae for sustainable transport fuels, not just SAF but also marine fuels. We now have new ways to process the microalgae; we're focused on reducing the cost and ensuring it can be sustainably and economically processed in a way that fits a SAF supply chain.

Promising results so far?

So far, the majority of the efforts have been focusing on selecting an algae species; there are actually millions of different species. The researchers have successfully narrowed this down, and have been working on microalgae cultivation and then processing: how the cell can be broken down and the oil lipids extracted. We have had promising results in terms of energy inputs; we are using solely waste products to grow the algae, so from a life cycle point of view, it looks promising.

What would you like to see happen next?

To come up with the amount of SAF that is needed if the aviation industry continues to grow the way it has grown, we need more than microalgae; we need every single pathway and feedstock. For this to become a reality, we need that middle-stage funding that will take all of the innovative projects from proof of concept to pilot scale and ultimately commercial production, and it's that middle funding that is so hard to find. There are so many opportunities and options to get there, but rather than become tunnel-visioned into just pursuing one opportunity, we have to run all of the available options on parallel tracks.

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