What is sustainable aviation fuel and will it take off?

10 Jan 2023

Image: © Dmitry_Evs/Stock.adobe.com

The production of these green fuels appears to be on the rise, though there are still limiting factors such as low availability and high costs.

Like many industries, aviation is looking to reduce its environmental impact and become more sustainable.

Last year, a United Nations body agreed to the goal of having the aviation industry reach net zero emissions by 2050.

One method that could help reach this target is the use of sustainable aviation fuel (SAF), which can significantly reduce the level of emissions created by aircraft.

Last year, the parent company of Aer Lingus and British Airways, IAG, entered a multi-year deal with renewable fuel company Aemetis to supply SAF for its San Francisco Airport flights from 2025, RTÉ reported.

In an article leading up to the World Economic Forum, Heathrow Airport CEO John Holland-Kaye argued that SAF is the “only option” for long haul flights to decarbonise.

“Long haul flights are responsible for 70pc of global aviation emissions, hence we urgently need to scale up production and drive down costs,” Holland-Kaye said.

What is sustainable aviation fuel?

In simple terms, SAF is a liquid fuel made from sustainable materials such as feedstock, which is shown to have a similar chemistry to conventional kerosene jet fuel. The fuel can be used in existing aircraft and blended with kerosene fuel if needed.

The biggest difference is in carbon emissions, with BP claiming SAF gives up to an 80pc reduction in emissions compared to traditional jet fuel, depending on factors such as the feedstock used, production methods and airport supply chains.

Siobhan Dolan Clancy is the founder and director of the ZE-Aviation Alliance, a not-for-profit in Ireland’s midwest region that aims to accelerate market readiness for zero-emission aviation tech.

Dolan Clancy told SiliconRepublic.com that SAF can be produced from a number of approved biological feedstocks, such as cooking oils, certain animal fats and “advanced biofuels” produced from agriculture residues, algae and bio waste.

She also said the aviation industry’s goal of reaching net zero emissions will be “hugely challenging” to achieve in a short time frame, though SAF could help significantly.

“By far the most significant tool will be SAF which is estimated could contribute around 65pc of the reduction in emissions needed by aviation to reach net-zero in 2050,” Dolan Clancy said.

There has been a push to make flights using SAF a reality for years in Ireland. At the BT Young Scientist & Technology Exhibition in 2019, one student set out to prove how ultrasound-assisted hydrothermal liquefaction of micro-algae can result in renewable jet fuel.

The same year, an Irish team at the Bernal Institute based at the University of Limerick signed a deal with a Dutch spin-out to explore SAF manufacturing in Ireland.

Is the market growing?

The demand for SAF appears to be on the rise. The International Air Transport Association estimated in December that SAF production would reach between 300m to 450m litres of production for 2022, an increase of at least 200pc compared to 2021.

The association also said a target of reaching 30bn litres of SAF production by 2030 is within reach, though IATA director general Willie Walsh has pushed for incentives to support this growth.

“Governments, who now share the same 2050 net zero goal, need to put in place comprehensive production incentives for SAF,” Walsh said.

The EU has been taking steps to try increase the production of SAF in the coming years. For example, the European Green Deal proposes a new support scheme to speed up SAF use, which will be backed by an estimated €1.6bn if adopted.

The EU also plans to introduce mandates in 2025, which will set a minimum obligation for fuel suppliers to ensure there is SAF being used in all EU airports.

Various companies, including airlines, travel agents and fuel producers are also offering bulk purchases of SAF to corporate customers, according to a Reuters report last month.

“We are seeing airlines sign up to multi-year supplies of SAF with off-take agreements for delivery even before mandates come into effect in 2025,” Dolan Clancy said.

What are the challenges for SAF production?

Despite an uptake in SAF and new mandates planned for the years ahead, Dolan Clancy said there are a number of limiting factors for SAF production such as low availability, scalability and high competition for sustainable feedstocks.

“The current price of SAF which can be three to five times more expensive compared to Jet A-1 remains one of the major barriers to its adoption by the airline industry,” she said.

Dolan Clancy believes that an “exponential expansion” of synthetic SAF or “electro fuels” will be needed for the industry to hit net zero emissions by 2050.

These e-fuels are produced using green hydrogen and captured CO2, but Dolan Clancy said the technology is currently immature, energy intensive and requires an expansion of global clean energy production.

Currently, green hydrogen and renewable electricity are not considered as synthetic aviation fuels, though there are discussions in the EU to have these fuels be listed under this term.

Dolan Clancy said the Irish Government does not have an SAF manufacturing strategy in place and argued that one is needed to help the country achieve fuel security.

“We should recognise as an island nation that SAF production offers fuel security as an additional benefit and continued competitive access to our international markets,” Dolan Clancy said.

“If we do not pursue a SAF manufacturing strategy in Ireland we limit our airlines to availability and price fluctuations and lack of security of supply in the open market.”

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Leigh Mc Gowran is a journalist with Silicon Republic