Sustainable Aviation Fuel

What is Sustainable Aviation Fuel?

Sustainable aviation fuel (SAF) is a renewable energy source derived from non-petroleum feedstocks such as biomass, used cooking oil, municipal waste, agricultural residue, and other sustainable sources. Its importance in aviation sustainability lies in its ability to significantly reduce carbon emissions compared to traditional jet fuels. Drop-in SAF can be seamlessly integrated into existing aircraft and infrastructure, offering a tangible and immediate way to mitigate the environmental impact of air travel. Its use addresses the aviation industry’s commitment to lowering greenhouse gas emissions, promoting low-carbon energy alternatives, and advancing the overall goal of sustainable aviation practices. Today, our turboprops are the most efficient and lowest emitting regional aircraft worldwide.

Drop-in Sustainable Aviation Fuel (SAF) is produced by converting organic and waste-based materials into a liquid fuel that can be used in conventional jet engines without modification. Unlike fossil-derived kerosene, SAF relies on renewable feedstocks and several different production pathways, each with its own process and carbon-reduction profile. 

The main feedstocks 

The starting materials for SAF include used cooking oil, agricultural residues (such as wheat straw or corn stalks), municipal solid waste, woody biomass, and animal fats. Some advanced pathways even use captured CO₂ combined with green hydrogen, a route called Power-to-Liquid (PtL). 

Key production pathways 

There are eight technical pathways for the production of SAF approved by ASTM International, a global standards and testing body. Here are some of the most known pathways:  

• The most commercially mature process today is HEFA (Hydroprocessed Esters and Fatty Acids). It takes fats, oils, and greases, like used cooking oil, and passes them through a hydroprocessing reactor where hydrogen removes oxygen and converts the triglycerides into hydrocarbons that closely mimic jet fuel.  

• Another route, FT-SPK (Fischer-Tropsch Synthetic Paraffinic Kerosene), converts solid biomass or municipal waste into a gas (a mix of CO and hydrogen called syngas) through a process called gasification. That syngas is then passed over a catalyst and reformed into liquid hydrocarbons. This pathway can handle a wider variety of feedstocks and produces very low-carbon fuel, though the technology is more complex and capital-intensive. 

• A third pathway, ATJ (Alcohol-to-Jet), starts with ethanol or isobutanol , which can themselves be made from sugarcane, corn, or agricultural waste, and chemically converts them into jet-range hydrocarbons through dehydration, oligomerization, and hydrogenation steps. 

• The Power-to-Liquid pathway uses renewable electricity to produce green hydrogen via electrolysis, then combines it with captured CO₂ in a Fischer-Tropsch or methanol-based synthesis to produce synthetic kerosene. This approach has the highest potential for near-zero or even net-negative carbon emissions but is currently the most expensive at scale. 

How much does it reduce emissions? 

Depending on the feedstock and production route, SAF can reduce lifecycle CO₂ emissions by 50% to over 80% compared to conventional jet fuel. The HEFA pathway, using used cooking oil, typically achieves reductions of around 80%. 

Is it ready to scale? 

SAF is certified for blending with conventional jet fuel at up to 50%. Today, global production remains a fraction of aviation’s total fuel demand, but investment is accelerating, driven by regulatory mandates in the EU, the UK, and the US, as well as airline net-zero commitments. 

The Role of SAF in Sustainable Regional Aviation 

Regional aviation connects communities that roads and railways cannot easily reach. It links islands, mountain towns, and remote regions to the wider world often with no alternative. But this connectivity has come at a carbon cost. Today, as the aviation industry faces mounting pressure to decarbonise, Sustainable Aviation Fuel (SAF) has emerged as the most credible near-term solution and ATR, the world’s leading regional turboprop manufacturer, has placed it at the heart of its sustainability strategy. 

ATR’s sustainability roadmap has several interlocking pillars: 

Full SAF Compatibility 

ATR turboprop aircraft are already certified to operate on SAF blends up to the current 50% limit. We have committed to achieving 100% SAF compatibility on our aircraft, and have been working with engine partner Pratt & Whitney Canada and fuel suppliers to validate performance across the entire SAF blend range. This certification work is critical: it gives airlines the confidence to adopt higher SAF blends as supply increases and costs come down. 

Flight Demonstrations and Industry Leadership 

ATR turboprop aircraft have participated in several demonstrations, using either SAF blends or pure HEFA, hereby validating real-world performance, gathering operational data, and signaling to the industry that turboprops are on the path toward the energy transition. These demonstrations serve a dual purpose: technical validation and market confidence-building among airlines, lessors, and regulators. 

Supporting the SAF Supply Chain 

We actively engage with fuel producers, governments, and aviation bodies to advocate for SAF scale-up. The airline industry faces a significant supply gap: current SAF production covers only a fraction of global aviation fuel demand. Closing that gap requires investment in new production facilities, supportive regulatory frameworks, and long-term offtake commitments from airlines. ATR’s advocacy in regional aviation forums is aimed at ensuring that smaller operators, who often lack the purchasing power of major carriers, can access SAF on fair terms. 

The Efficiency-SAF Multiplier 

One of the most compelling arguments is the compounding effect of combining fuel efficiency with SAF. An ATR 72-600 already uses 45% less fuel per seat than a comparable regional jet. Running that same aircraft on a high-blend SAF further reduces its carbon footprint, meaning the emissions savings multiply rather than add. For regional routes where connectivity cannot be sacrificed, this combination offers the most viable path to sustainable operations without reducing service. 

Looking Ahead: SAF as a Bridge to Zero 

Our vision is not that SAF is the final destination; it is the bridge. We are investing in research into hybrid-electric propulsion as one of the longer-term options for regional aircraft. 

In the meantime, SAF offers tangible advantages today, with the capacity to be deployed on existing aircraft, on existing routes, serving existing communities. For the thousands of regional routes that ATR turboprop aircraft serve across Europe, the Pacific, Africa, Latin America, and beyond, SAF is not a compromise; it is a realistic, responsible, and commercially viable path to meaningful emissions reduction in this decade. 

Our ambition is clear: to make regional aviation a model for sustainable connectivity. SAF is not a footnote to that ambition. It is central to it. 

Today, our turboprops are the most efficient and lowest emission regional aircraft worldwide, and they are already 50% SAF compatible.

Yet, we want to further drive the decarbonisation of air transport and strongly believe that Sustainable Aviation Fuel (SAF) will play a critical role to this end both in the short and long term.

With 80%* emissions reduction over its lifecycle versus conventional jet fuel, SAF powers aviation’s flightpath to a reduced carbon footprint. SAF-powered aircraft provide additional non-CO2 benefits thanks to significantly reduced particulate emissions.

In 2022, ATR made history as the first manufacturer to successfully complete a test flight with 100% SAF in both engines of a commercial aircraft. We are waiting for the international fuel standard validation by ASTM, in the second half of the decade, to achieve the 100% SAF compatibility of our entire aircraft family.

Along with other key players in aviation, we are committed to contributing to the Paris Agreement targets, by adopting a clear roadmap to reduce our greenhouse gas emissions.

Since August 2023, all our production test flights are powered with 30% SAF, which represents a saving of almost four tonnes of CO2 per flight.

In the future, we plan to extend the use of SAF to all our test flights performed by our prototypes.