Flying has an emissions problem. Sustainable aviation fuel (SAF) should play a major part in tackling this. The UK is starting to see companies exploring various novel ways to process waste, of various kinds, into aeroplane fuel.

The International Air Transport Association (IATA) expects SAF to account for the lion’s share of emissions reductions in the sector. The organisation has said it should reduce make up 65% of the reduction, to achieve net zero by 2050.

Other contributions will come from new technologies, such as electricity and hydrogen, account for 13% and carbon capture and offsets at 19%. The remaining 3%, IATA hopes, will come from infrastructure and efficiencies.

SAF has yet to take off, but the IATA suggests the 2030s will see a “massive increase” in order to meet demand. In this next decade, the group says, SAF should become competitive with kerosene.

Without SAF, the airline industry will produce an expected 1.8 billion tonnes of carbon emissions in 2050. For SAF to meet its 65% target, industry will need to produce more than 360 million tonnes (450 billion litres) per year of SAF by that year.

In 2022, the world produced 240-380,000 tonnes. Airlines bought all this production, costing an additional $322-510mn.

The UK’s Jet Zero Strategy set out the aim to reach five plants under construction in 2025. Phillips 66 was first off the bat, supplying SAF from its Humber refinery to British Airways.

Political support

The UK, in April this year, set out its SAF target. The government has aimed for this new fuel to meet 10% of needs for all flights taking off from the UK by 2030.

It set the “ambitious but achievable” target of reaching 1.2mn tpy of SAF in the UK.

There has been some success in this area. In November 2023, a Virgin Atlantic flight flew from Heathrow to New York. The Boeing 787, using Rolls-Royce Trent 1000 engines, was fuelled entirely by SAF – a world first.

And there seems to be continued political support in the UK for the move into SAF. The Labour Party, in its manifesto, said promoting SAF was part of the “UK aviation industry’s long-term future”.

Christian Hvamstad, co-founder and chief strategy officer of Norway’s Wastefront, said the company was confident the UK would stick to the plan. The 10% target for 2030 “won’t be altered any time soon, and these heightened targets only reinforce the urgent need for innovative, cost-effective solutions like ours”.

SAF appeal

There is always the chance that targets may move. But the direction of travel, towards SAF, “remains unchanged. In fact, the global demand for SAF is projected to skyrocket, with a CAGR of 45% from 2024 to 2030, and more than 40 airlines have already publicly committed to using around 13mn tones of SAF by 2030.”

James Hygate, founder of Firefly Green Fuels, agreed the UK was an attractive place to work on SAF. “As a country, this is a big opportunity for us. Aviation is a big contributor to the economy here and we have an opportunity to green that.”

It is not just political support for cleaner flying, though, that makes these processes attractive. Firefly uses sewage as a feedstock for its SAF process. Sewage is “seen as a troublesome material in the UK and it’s readily available. We don’t actually have the land to deal with the amount of material in the UK. Every water company is looking for a solution to this problem.”

The SAF two-step

SAF can be produced from a range of different feedstocks. One of the most common options comes in processing waste products, such as waste fats or biomass. Another route to SAF production is through the combination of green hydrogen and CO2.

Wastefront is working on a plan to process old tyres into SAF at a plant in Sunderland. The company aims to bring its commercial plant online by the end of 2025, with SAF starting in 2028.

The Norwegian company said that SAF from hydroprocessed esters and fatty acids (HEFA) is constrained, because of challenges around availability. For tyres, on the other hand, processing them into useful products avoids landfill or incineration.

Wastefront expects to process around 80,000 tonnes per year of tyres at its Sunderland plant. It will also generate its own power, the company has said, reducing emissions further.

The first step involves converting end of life tyres into tyre pyrolysis oil (TPO). Initially, other refineries will process this into SAF.

“This strategy allows Wastefront to enter the SAF market quickly and cost-effectively. As the process matures, dedicated plants will convert TPO into SAF directly, starting in 2028. Although we are already in discussions with several major airlines across Europe, this approach reduces reliance on airline deals in the short term while setting the stage for future partnerships as SAF production scales up and the market demand increases.”

Integrated model

Hygate said Firefly was working on a “hub and spoke model”.

The hub is a refinery in Harwich, at a site controlled by Haltermann Carless. “We’re using a lot of their infrastructure, along with out bespoke hydrotreatment plant,” he said. Firefly is in partnership with Chevron Lummus Global.

“So we’ll have a small oil refinery in Harwich – which is a comparatively big SAF plant – producing the fuel. Then, dotted around close to wastewater treatment plants are our upstream, these are our oil wells.”

Waste is processed at these plants using hydrothermal liquefaction, producing bio oil and biochar. The company will then transport the oil to the refinery for processing. Firefly aims to produce around 100,000 tpy at its plant, half of which will be SAF and the rest gasoline.

Hygate said the hydrothermal liquefaction process relied on putting feedstock into a facility similar to a pressure cooker. It uses “moderate temperatures and pretty high pressure so that water becomes reactive – and it smashes apart the biomass of the material that’s in there.”

The process uses biosolids as an input, he explained. “It’s not like fresh poo, it’s poo that’s had all the lipids and everything else taken out of it. That upstream is kind of new, but it’s not wholly new, because it’s what happens in nature, just over millions of years.”

*James Hygate, founder of Firefly Green Fuels*

Flexibility

Not all such construction plans have gone smoothly. Shell announced earlier this month that it was pausing its project in Rotterdam, which was to use HEFA feedstocks to produce SAF.

Shell took final investment decision (FID) in 2021 on the plant, based on the Pernis refinery. It had planned capacity of 820,000 tpy.

The supermajor went on to declare a non-cash post-tax impairment of $600mn to $1 billion on the Rotterdam plant.

Firefly recognises the process has to be cost effective, said Hygate. The HEFA process is not complicated, but input costs are high, he noted. The more exotic SAF products, such as e-fuels, are much more complicated and challenging.

“I think one of the big advantages [Firefly] have is our feedstock is very low cost. There are processing costs, and it isn’t going to be cheaper than a fossil fuel, but we think we’re going to be very competitive against these routes,” he said. “The reality is, the industry needs all of these [options] to work. We need them all to decarbonise aviation.”

Hvamstad said Wastefront would mitigate cost and inflation challenges “through its innovative process, ultra-low cost of production methods and robust financial planning”. It uses commercially proven technologies, to TRL 9, as verified by Technip Energies, he noted.

Long-term feedstock agreements and using a modular plant design will also keep the company’s plans flexible, the official said.

“The Sunderland project’s phased implementation – starting construction with a smaller module in 2024 and expanding – helps manage costs, limit capital expenditure risks and ensures resilience against economic fluctuations.”

Ultimately, of course, a shift to more expensive fuel options must be paid by the consumer. Signs of this are on the way, with Lufthansa announcing an environmental cost surcharge for departures in Europe.

Strategic location

The location also helps, Hvamstad said. Wastefront chose Sunderland “due to its strategic location, excellent logistics and robust supply chain, making it ideal for our first commercial plant”.

“The region also provides ample feedstock of waste tyres, which is crucial for our goal to fast-track the production of [SAF] at an unprecedented low cost. Strong support from local authorities and stakeholders in Sunderland has been another significant factor.”

He cited co-operation from the Port of Sunderland and other local groups in supporting the project.

“Additionally, the area benefits from a skilled workforce, particularly in industries related to manufacturing, engineering, and renewable energy, enhancing the project’s prospects for success. As a graduate of the University of Sunderland and a former resident of the city, I have seen firsthand the vast potential Sunderland has to capitalise on the economic opportunities generated by the net zero agenda.”

*Wastefront’s plan at the Port of Sunderland*

It is not just in the UK where there are opportunities for SAF. Many countries are working on the problem. The European Union, for instance, has mandated SAF reach 2% in 2025 and 6% in 2030, rising to 70% by 2050.

The US has set out incentives for SAF production, based on an emissions reduction of at least 50%. United Arab Emirates’ Masdar struck a deal with BP in early 2023 to explore SAF from hydrogen and municipal waste.

Hygate said that while Firefly’s first move was in the UK, it was likely to be developing projects “very soon elsewhere in the world, but we really want the first one to be here in the UK to be the showcase”.

Next steps

As with many innovative processes, starting off and scaling up are major challenges. “Innovation is always tricky,” Hygate agreed. To bring in funding from banks, there is a need to fully de-risk a project.

The UK government provided some seed funding for Firefly to prove out its process and more recently Wizz Air came onboard. The airline has been “brilliant”, Hygate said. “They could see the opportunity. So they invested in the business, but that was alongside a contracted offtake agreement.” Wizz Air has agreed to take 525,000 tpy of Firefly’s production over 15 years.

Such a deal makes further agreements a “much easier conversation”, he said. The deal is big enough to be bankable, but also leaves Firefly with unsold production which it can offer to others.

The company is in the process of going through a funding round. “What’s exciting for us is we feel that we’re able to choose strategic partners that are going to really help us at the next step,” the executive said. The focus is not just on getting the first plant up and running, it’s also about the “second, third, fourth and everywhere in the world, because this is something that can be done everywhere”.

Once the first project is built, though, financing will become easier. When that is de-risked, “there’s lots of financial institutions that have approached us for financing the projects down the line”.

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