In this episode of ‘Sustainability in the Air’ podcast, Valérie Guénon, Vice President of Product Environment Policies at Safran Aircraft Engines, speaks with SimpliFlying’s CEO Shashank Nigam and shares how the company aims to tackle environmental challenges through innovative engine design and sustainable fuel integration.
With 36 years at Safran, Guénon brings deep expertise in aircraft engine design and environmental strategy, offering insights into how technological advances are reshaping aviation’s environmental impact.
Here are the key highlights of the conversation:
Engine efficiency vs environmental impact (3:43)
RISE engine program and Open Fan technology (6:55)
Making engines 100% SAF compatible (16:32)
Safran’s role in scaling up SAF production (22:26)
Electric and hybrid propulsion developments (27:25)
Impact of increasing flying costs on demand (39:12)
Gender diversity in aerospace engineering (47:52)
Rapid Fire! (51:49)
Keep reading for a detailed overview of the episode.
Why engine innovation matters for sustainable aviation
As aviation grapples with its environmental impact, engine innovation will be a critical lever for reducing emissions. The significance of engine technology becomes clear when considering lifecycle emissions data.
“Over its lifetime, an engine emits CO2. More than 95% of these CO2 emissions is due to the operating of the aircraft”, explains Guénon, highlighting why engine efficiency is paramount for sustainability.
“For decades, we have worked on engine efficiency for economic reasons”, notes Guénon, “and the good news is that it has gone in the same direction as reducing the CO2 emissions per passenger kilometre.” This alignment between economic and environmental benefits has driven sustained investment in engine technology.
The environmental impact of aircraft engines, however, extends beyond just CO2 emissions. As Guénon notes, “Engines also make a lot of noise. And noise around the airports is also a question of health... it is an environmental impact”. Additionally, engines emit pollutants that affect local air quality, including NOx, particulate matter and carbon monoxide, similar to urban vehicle emissions.
The need for engine innovation becomes even more pressing when we consider future regulatory demands. As environmental standards grow stricter, manufacturers must proactively prepare for these changes.
4 takeaways from the conversation
1. Addressing integration challenges with Sustainable Aviation Fuel (SAF)
Integrating SAF into existing aircraft systems is a complex engineering challenge that goes beyond simply replacing traditional fuel, says Guénon. While current aircraft certifications permit blending up to 50% SAF with conventional jet fuel, the industry is working toward enabling operations with 100% SAF. Achieving this transition involves carefully assessing how SAF interacts with various aircraft systems.
A particularly challenging aspect is the variable nature of future fuel scenarios. Aircraft will need to operate seamlessly when refuelling at different airports with varying SAF blend ratios, from pure conventional jet fuel to 100% SAF.
The fuel’s role extends far beyond combustion, as Guénon emphasises: “The fuel is not only used for burning; it’s also used in systems for actuation and cooling.”
Whilst the technical challenges of SAF integration appear manageable from an engineering perspective, the greater hurdles lie elsewhere. “The main challenge with SAF is not entirely in our hands”, notes Guénon, “because it’s about availability and costs.” The successful deployment of SAF requires coordination across a complex value chain involving fuel producers, airports, transportation infrastructure, financial institutions and policymakers. This underscores that the shift to SAF is not only a technical challenge, but also a broader industry transformation that demands collaboration among multiple stakeholders.
2. Future propulsion technologies: electrification and hydrogen
In addition to advancing SAF, Safran is also pursuing electric and hydrogen propulsion, each presenting unique opportunities and challenges for different segments of aviation. The company’s expertise in these technologies spans over two decades, with efforts initially focusing on the electrification of non-propulsive aircraft functions to reduce fuel consumption.
Through Safran Electrical & Power, the company’s centre of excellence for aircraft electrification, significant progress has been made in developing electric propulsion solutions. Their EngineUS family of electrical engines targets specific market segments where electrification shows particular promise.
“Electrification will work on smaller vehicles,” notes Guénon, explaining that the technology is particularly suited to “helicopters or smaller aircraft, training aircraft commuters.”
Safran’s hydrogen propulsion program leverages the company’s extensive experience with liquid hydrogen, gained through its Ariane Group joint venture with Airbus, which develops rocket propulsion systems. While hydrogen offers the key advantage of zero CO2 emissions during combustion, its adoption comes with major technical and infrastructure challenges. As Guénon explains, “Designing a vehicle with a completely new type of fuel, at -235 degrees Celsius, with different chemical and physical properties and density, is a real challenge.”
These challenges extend beyond aircraft design to the broader operational ecosystem. The extremely low temperature of liquid hydrogen requires specialised handling and storage infrastructure. Additionally, hydrogen’s tendency to leak when transitioning from liquid to gaseous state introduces unique safety concerns. “It also impacts production and distribution infrastructure, with various concerns about security, safety, and clearance zones for refuelling,” Guénon adds. The availability of hydrogen at different airports further complicates its widespread use.
3. Revolutionary Innovation for Sustainable Engines: The RISE Programme
The Revolutionary Innovation for Sustainable Engines (RISE) program marks a significant step forward in aviation propulsion technology, developed through the long-standing partnership between Safran Aircraft Engines and GE Aerospace. Building upon their successful collaboration through CFM International, which produced the previous-generation CFM56 and current-generation LEAP engines, RISE aims to define the next evolution in sustainable aircraft propulsion.
Rather than focusing on a single engine development, RISE is a broad technology innovation initiative. “It’s a set of technology demonstrations and covers a range of solutions,” explains Guénon, emphasising the program’s comprehensive approach to sustainable propulsion.
The initiative includes multiple engine architectures and demonstrators, with the most notable being the groundbreaking Open Fan engine design. The open fan architecture marks a radical shift from traditional turbofan design by removing the engine nacelle and casing, focusing on enhancing propulsive efficiency and reducing fuel consumption, says Guénon.
4. Economic realities of sustainable aviation
The transition to sustainable aviation brings significant economic implications. “Flying will not become cheaper because our levers are very costly”, Guénon observes. While the industry can make substantial emissions reductions through technological innovation, it will probably result in higher costs for both operators and passengers.
“It is very costly to develop technologies. Airlines will have to buy [new] aircraft and renew their fleet, and they will also have to buy SAF, which is very costly.”
The impact of these costs is already being modelled in industry roadmaps. As Guénon notes, “We are updating the European roadmap called Destination 2050, where we are modelling various parameters, and we observe that the cost of SAF is probably what will have the most impact on traffic limitation.” However, she emphasises that regardless of cost implications, the fundamental principle remains unchanged: “No matter what fuel we use, we must burn less of it while carrying the same passengers the same distance.”
‘Sustainability in the Air’ is the world’s leading podcast dedicated to sustainable aviation. Through in-depth conversations with top aviation leaders, we break through the clutter and provide a clear roadmap for a net-zero future.
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