Innovation powering the future of renewable fuels

From the breakthrough of hydrotreated vegetable oil (HVO) to the commercialization of sustainable aviation fuel (SAF), the renewable fuels industry has come a long way in just two decades. Yet, despite progress, the journey is still only beginning. The demand for renewable fuels is expected to grow as industries from aviation to heavy transport seek lower-GHG-emission alternatives to fossil fuels.

Scaling renewable fuels to meet the increasing demand globally requires continuous technological innovation – not only in production methods and raw materials use, but also in ensuring compatibility, efficiency, and cost-effectiveness.

“Perhaps the most important task for innovation is to expand and diversify the raw material pool. The raw materials that Neste currently uses are largely based on wastes and residues like oils and fats, which provide only a limited raw material base. We need to unlock new sources and develop technologies to turn them into fuels,” explains Petri Lehmus, Vice President of Research and Development at Neste.

He adds that as the competition for raw materials has become increasingly fierce, continuously developing the ability to process new raw materials is essential for maintaining a competitive edge in the lower-emission fuel market.

Innovation as the key to scale-up

Neste’s innovation journey began with its proprietary NEXBTL™ technology, which allows the conversion of a wide range of renewable raw materials into high-quality renewable fuels in a catalytic process. This breakthrough paved the way for renewable diesel and SAF production at commercial scale.

Today, the focus has shifted to scaling up and broadening the raw material base. New streams such as lignocellulosic biomass – forest and agricultural residues – could multiply the potential of renewable fuels.

“Lignocellulose could open up a market providing hundreds of millions of tons of new, scalable raw materials. That would multiply the renewable fuel business far beyond what fats and oils can achieve,” says Lehmus.

At the same time, advancements in pre-treatment and purification technologies are essential. Renewable raw materials typically come with impurities that must be removed to ensure consistent quality and compatibility with strict fuel specifications – especially in aviation.

Aviation push towards net-zero carbon emissions

The aviation industry, responsible for roughly 2–3% of energy-related global CO₂ emissions, has limited near-term alternatives to reduce aviation emissions. Astrid Sonneveld, Technical Lead of Neste’s Renewable products organization, says that aviation cannot decarbonize without SAF. “No matter which roadmap you pull up, SAF is the single biggest lever for reaching the aviation sector's commitment of net-zero carbon emissions by 2050,” Sonneveld says.

However, Sonneveld adds that reducing greenhouse gas (GHG) emissions alone is not enough to mitigate the climate impact of aviation. So-called non-CO₂ effects, such as contrails – the line-shaped exhaust clouds visible behind jet aircraft – must be addressed as well.

“Jet fuel in the future needs to be made not only from renewable sources, but it also needs to burn cleaner,” she says.

The advantage of SAF is that it’s a drop-in solution: every commercial aircraft today can fly on blends of SAF without modifications to the aircraft engines and fuel infrastructure. But going beyond blending with conventional jet fuel to 100% SAF use requires close cooperation with aircraft and engine manufacturers. This is where partnerships come in.

“For example, Rolls-Royce has been a frontrunner in redesigning aircraft engines for a net zero future. We have collaborated closely for many years on reducing emissions from both diesel and aircraft engines,” says Sonneveld.

Collaboration driving real-world solutions

Rolls-Royce’s Alastair Hobday, Associate Fellow, Fuels and Lubricants, describes innovation as central to the company’s approach.

“We are committed to demonstrating that our engines are capable of operating on 100% SAF. So, we undertook a significant program of ground and flight testing to prove that even if 100% SAF cannot be used commercially today, our technology is future-proof,” Hobday says.

One example of joint innovation is the ECLIF3 program, a collaboration between Rolls-Royce, Airbus, Neste, and the German Aerospace Center DLR. By flying an Airbus A350 powered by Rolls-Royce Trent XWB engines using Neste’s SAF, researchers could directly measure in-flight emissions and contrail characteristics. The results provided data on how SAF reduces not just CO₂ emissions but also the non-CO₂ impact of aviation.

This work continues through the PACIFIC project, which is deepening the industry’s understanding of aviation’s non-CO₂ effects.

Sonneveld notes the importance of such partnerships. “Our technical experts learn from Rolls-Royce, and vice versa. This is critical to driving innovation.”

From innovation to commercial use

Beyond technical innovation, affordability is vital. “Lower-GHG-emisson fuels are needed, but if their price is too high, they won’t take off,” Lehmus emphasizes. “Our task is to find the most impactful and cost-effective solutions that society can actually adopt at scale.”

For customers, the priorities are reliability, compatibility, and supply certainty. As Hobday points out:

“There is no need to modify existing engines to operate on SAF. We need drop-in solutions that work across fleets, from engines designed in the 1950s to those designed today.”

However, for Rolls-Royce, innovation is also about new engine architectures. “Our UltraFan engine is next-generation technology, designed to deliver significant efficiency improvements,” Hobday explains. “Combined with SAF and, in the future, eSAF, it will be a critical step forward.”

Renewable fuels: the next frontier

The road ahead for renewable fuels involves both incremental improvements and breakthrough innovations. Scaling up production capabilities and advancing favorable regulatory frameworks are critical future developments. On the horizon, e-fuels – made from renewable electricity and captured CO₂ – are in early stages of development but expected to increase costs. “Technically, they are possible,” Lehmus says. “But if fuel prices suddenly quadruple, society simply won’t adopt at scale.”

Compared to e-fuels, the use of lignocellulosics is a much more readily available solution. Vast amounts of lignocellulosic waste and residues from existing forest industry and agricultural production remain underutilized. Neste and Chevron Lummus Global are currently validating a novel technology for processing these raw materials and targeting readiness to scale up the technology to commercial scale.

From expanding raw material pools to developing new propulsion technologies and collaborating across industries, innovation is the compass guiding Neste and its partners toward a lower-emission transport future.

As Sonneveld puts it, cooperation and innovation must go hand in hand: “Success in decarbonizing hard-to-abate industries can only be achieved together.”