The Perils of Pauline: Can Haffner Energy Save SAF Before the Train Arrives? New SB-HEFA tech points the way

A young woman is tied to the railroad tracks. A villain, having twirled his mustache and completed his wicked work, has departed the scene. Rumbling nearer and nearer is a locomotive, its iron wheels screaming against the rails as its smokestack belches smoke into the desert sky. The heroine struggles. The ropes hold. The air thickens with the stench of coal smoke and hot grease. The whistle shrieks, splitting the desert air. The looming cowcatcher casts a long shadow, coming closer, closer.

And where, we ask, is the hero?

Well, friends, welcome to the sustainable aviation fuel industry in 2026. Our heroine is a SAF project. A perfectly promising project, with an experienced developer, an attractive location, an airline interested in buying the fuel, and a business plan that promises to turn waste into the hydrocarbons that aviation needs.

There is just one problem: the numbers don’t quite work. The feedstock is too expensive. The plant costs too much to build. The fuel commands a premium that customers may be unwilling or unable to pay. And the financiers, who have heard many wonderful stories about the future of sustainable aviation, are proving remarkably reluctant to write checks for the present. Meanwhile, the development budget is running down. The construction timetable is slipping. The promised delivery dates are approaching. The locomotive is coming.

Our heroine needs more than a sympathetic banker, a larger subsidy, or another enthusiastic announcement about the future of green aviation. She needs a different set of economics. And now, riding into the picture from France, comes Haffner Energy.

Enter the hero: A new route from biomass to fuel

On September 22, Haffner Energy unveiled SB-HEFA, short for Solid Biomass to Hydroprocessed Esters and Fatty Acids, a proposed pathway for converting residual solid biomass into renewable diesel and, ultimately, sustainable aviation fuel. The proposition is striking.

Instead of depending on the limited pool of used cooking oil, animal fats, and other lipid feedstocks that supply conventional HEFA production, Haffner proposes to use abundant solid biomass residues. Instead of following the conventional biomass-to-liquids route through synthesis gas and subsequent fuel synthesis, the company proposes to recover a liquid intermediate directly from its thermolysis process and upgrade it into renewable hydrocarbons. And instead of accepting the cost structure associated with those established routes, Haffner is targeting a reduction of approximately 50 percent in levelized production costs. The company says the primary energy cost of its solid biomass feedstock can be less than one-fifth that of the oils used in conventional HEFA production.

These are ambitious claims. They are not yet the measured economics of a commercially operating SB-HEFA facility. But if Haffner can deliver them at industrial scale, the implications extend well beyond one technology developer’s product portfolio. They reach directly into the question that has been haunting the SAF industry: how do we build enough affordable production capacity to turn ambitious aviation decarbonization targets into actual gallons of fuel? And how do we persuade the people with the money to finance the plants? Because that, friends, is where our heroine is in trouble.

The ropes: SAF’s feedstock and financing predicament

The SAF industry has a curious problem. There is considerable interest in the fuel. Airlines have announced procurement commitments. Governments have established incentives and blending requirements. Developers have unveiled projects representing substantial prospective production capacity. Yet the journey from announcement to final investment decision has proved difficult.

The problem is not simply a shortage of enthusiasm. A project developer must secure feedstock, establish a reliable conversion process, arrange construction, obtain the necessary approvals, negotiate fuel sales, and persuade investors and lenders that the resulting cash flows will support the capital required. And the arithmetic can be unforgiving.

Conventional HEFA has an important advantage: it is an established industrial pathway for producing renewable hydrocarbons from oils and fats. Its disadvantage is that the supply of suitable feedstocks is constrained, while renewable diesel, SAF, and other industries compete for many of the same materials. Used cooking oil is a useful feedstock, but it is not an infinitely expandable resource. Animal fats are useful, too, but the number of animals available to supply them does not increase merely because another airline announces a SAF procurement target.

There is, however, another enormous reservoir of potential feedstock: forestry residues, agricultural residues, wood-processing byproducts, and other qualifying forms of residual solid biomass. The difficulty has been finding an economical way to convert these materials into finished liquid fuels at industrial scale. That brings us to the second rope.

The expensive journey through synthesis gas

In a conventional biomass-to-liquids process, solid biomass can be gasified or otherwise converted into synthesis gas, a mixture principally of hydrogen and carbon monoxide. That gas can then be cleaned, conditioned, and converted into liquid hydrocarbons through Fischer–Tropsch synthesis, or into methanol for subsequent upgrading.

These are technically established approaches, but integrating the complete chain into a commercial biomass-to-fuels facility involves substantial equipment, energy consumption, capital investment, and operational complexity. The biomass must be prepared. The gas must be produced and cleaned. Its composition must be adjusted. The liquid molecules must be synthesized and upgraded. It is a formidable undertaking.

Imagine loading a train with timber, sending it a thousand miles to a sawmill, reducing the timber to sawdust, and then building an entirely new forest of trees so that you can make lumber. There are sound industrial reasons for taking the long way around. But if you can recover useful material earlier in the journey, you might not need all those extra miles.

That, in essence, is Haffner’s proposition: stop the train at the liquid intermediate, recover the oil, upgrade it into fuel, and skip the journey through synthesis gas and back again. For a project already struggling to make its economics work, eliminating processing stages could make a meaningful difference to its capital requirements. But how?

The secret weapon: Don’t turn the oil into gas

Here is where Haffner’s story becomes particularly interesting. For years, the company has developed thermolysis technology that converts solid biomass into useful energy products. Its existing technology platform provides an industrial foundation for the new process. But SB-HEFA proposes a different destination for the products of thermolysis.

In Haffner’s established hydrogen and syngas applications, the condensable organic compounds generated during thermolysis are reformed into gas. For SB-HEFA, the company proposes to recover those compounds as a liquid intermediate instead. The central idea is to preserve useful liquid fuel precursors rather than subject them to further conversion into synthesis gas and then reconstruct liquid hydrocarbons from smaller molecules.

This is not simply another biomass gasification process with a different name. It is a proposed shortcut through the chemistry. And the critical moment comes almost immediately after thermolysis.

The race against the clock inside the reactor

The biomass enters Haffner’s thermolysis process, where heat breaks down its complex organic structure. The resulting vapors contain compounds that can be recovered as a liquid intermediate. But these compounds do not necessarily remain intact under prolonged exposure to high temperatures; further thermal reactions can break them down into smaller molecules, including non-condensable gases. For a process designed to produce syngas, that may be an acceptable or even desirable outcome. For a process designed to recover liquid fuel precursors, it is precisely what the operator wants to avoid.

The answer is rapid cooling. Haffner proposes to cool the thermolysis products quickly enough to recover the liquid fraction before further decomposition destroys the desired intermediate. The recovered oil is then filtered to remove residual solid particles. Finally, it undergoes hydrodeoxygenation, or HDO, in which hydrogen is used to remove oxygen from the organic compounds and produce renewable hydrocarbons. The resulting hydrocarbons can then undergo the finishing and qualification steps appropriate to their intended fuel market.

The proposed chain is comparatively straightforward: solid biomass $\to$ thermolysis $\to$ rapid cooling and oil recovery $\to$ filtration $\to$ hydrodeoxygenation $\to$ renewable hydrocarbons.

The important distinction is that Haffner is not claiming to have invented hydrodeoxygenation. HDO is an established industrial technology, already used in renewable fuels production. The proposed innovation lies in the combination of Haffner’s thermolysis technology, the recovery of a suitable liquid intermediate, and its subsequent upgrading through an established hydroprocessing route.

The company says its approach produces an intermediate with lower oxygen content and acidity than conventional fast-pyrolysis oils, reducing the burden on downstream upgrading. That could matter enormously. Biomass-derived oils can contain substantial quantities of oxygenated compounds, water, acids, and other materials that complicate refining. Their composition influences hydrogen consumption, catalyst performance, equipment requirements, and the yield of finished hydrocarbons. An oil that is easier to upgrade could make a meaningful difference to the economics of the complete plant.

But there is one passenger Haffner cannot leave behind at the station.

Hydrogen: The passenger who must come along

Biomass contains oxygen. Jet fuel and renewable diesel contain very little. To turn a biomass-derived oil into a finished hydrocarbon fuel, that oxygen must go somewhere.

Hydrodeoxygenation can remove it as water, using hydrogen in the process. Other reactions can remove oxygen by releasing carbon dioxide or carbon monoxide, potentially taking valuable carbon along for the ride. Fischer–Tropsch has its own hydrogen requirements, beginning with the need to produce synthesis gas with the appropriate composition.

The question, therefore, is not simply whether Haffner can skip the syngas detour. It is how much hydrogen the new route consumes, how much biomass carbon reaches the finished fuel, and what the complete process costs. Haffner’s proposed lower-oxygen intermediate could reduce the burden on downstream upgrading, but the hydrogen balance and finished-fuel carbon yield will have to be demonstrated for the integrated process.

And where will that hydrogen come from? Haffner’s existing technology platform includes hydrogen production, but the company must establish the hydrogen supply and integration strategy for the SB-HEFA process. Will hydrogen be supplied externally, produced on-site, or recovered through an integrated process configuration?

The answer matters. Hydrogen has a cost, an associated emissions profile, and a substantial influence on the economics of hydroprocessing. A shorter conversion chain is valuable only if the costs of producing and upgrading the recovered oil do not consume the savings. The train may have found a shorter route, but it still needs fuel to get there.

Three ropes. Three possible cuts.

Our heroine is still on the tracks. The banker is still shaking his head. The locomotive is getting closer. Haffner proposes to change three things:

First, the feedstock. Instead of competing for used cooking oil and animal fats, SB-HEFA draws on residual solid biomass. Haffner says its primary-energy cost can be less than one-fifth that of the oils used in conventional HEFA production. The draft economics suggest solid biomass costs of approximately €10–€30 per MWh, compared with approximately €100–€120 per MWh for conventional oil-based feedstocks. Those are substantially different starting points.

Second, the equipment. By recovering a liquid intermediate rather than taking the conventional syngas route, the company aims to eliminate some of the processing stages associated with gas reforming, conditioning, and subsequent fuel synthesis. Haffner estimates that the capital cost of an SB-HEFA facility could be approximately one-third that of certain conventional Fischer–Tropsch or methanol-synthesis biomass-to-liquids configurations. That comparison is indicative, and the precise plant capacity, configuration, and scope matter—but the potential advantage is substantial.

Third, the finished-fuel economics. Combine less expensive feedstock with a shorter process chain and lower capital requirements, and Haffner believes it can reduce levelized production costs by approximately 50 percent.

There is the proposition. But before our heroine begins celebrating, a word from the banker: half the production cost is not necessarily parity with petroleum, a cheaper feedstock is not necessarily a cheaper finished fuel, and a less expensive plant is not necessarily a financeable plant.

The relevant number is the cost of producing a saleable gallon, at the required specification, in the quantities and over the operating life assumed in the financing model. That number must include feedstock delivery, conversion yields, hydrogen, operating expenses, capital costs, and the cost of money.

Solid biomass must be collected, transported, stored, prepared, and delivered to the plant. Its moisture content, energy density, and chemical composition affect both logistics and conversion performance. A tonne of wood residues is not equivalent to a tonne of used cooking oil, nor does a fivefold difference in the cost of primary energy automatically translate into a fivefold difference in the cost of finished fuel. For SAF, the calculation must also account for the cost of producing an approved aviation fuel blendstock and the associated upgrading, blending, and distribution requirements.

Haffner has proposed a different set of economics. The industrial demonstrator must establish whether those economics hold. The ropes are not yet cut, but the knot may have loosened.

The hero takes a detour

The audience expects Haffner to gallop directly to the SAF project. Instead, the company heads for renewable diesel. This is not a mistake in the script; it is the commercialization strategy.

Renewable diesel offers an initial market in which Haffner can demonstrate the complete conversion process without first completing the aviation-specific qualification required for SAF. The fuel can serve existing diesel applications when it meets the applicable specifications, providing a potential commercial destination for the technology while the aviation pathway is developed.

Haffner intends to demonstrate the complete SB-HEFA process first in renewable diesel production, with an industrial demonstrator targeted for 2027–2028. Its existing Marolles site provides a starting point for the work, having already established the production of non-hydrotreated oil. The proposed next step is to integrate that intermediate with the downstream upgrading process and demonstrate production of the finished renewable fuel.

The distinction is important. Haffner is not starting with an entirely unfamiliar feedstock-conversion technology, nor is it proposing to invent a wholly new hydroprocessing industry. But integrating the two into a reliable, commercially competitive production chain is still a substantial engineering task. The renewable diesel demonstrator is intended to provide evidence of how that complete chain performs, and the information gathered there could support the subsequent development of the SAF pathway.

The hero has found a different route, but he has another stop to make before reaching our heroine.

The aviation qualification challenge

Haffner’s stated SAF commercialization horizon is 2030, aligning with the European Union’s 6 percent SAF supply requirement under ReFuelEU Aviation. The company intends to pursue qualification of its proposed pathway through the relevant ASTM aviation-fuel approval process.

This is not simply a matter of producing hydrocarbons that resemble conventional jet fuel. Aviation fuel must meet demanding requirements for properties such as freezing point, thermal stability, combustion performance, and material compatibility. The ASTM D4054 process provides a framework for evaluating new aviation turbine fuel production pathways and synthetic blending components, while ASTM D7566 establishes specifications for approved aviation turbine fuels containing synthesized hydrocarbons.

Haffner has identified the precedent of hydroprocessed hydrocarbons derived from certain biological feedstocks, including the HC-HEFA pathway, as relevant to its intended qualification strategy. But an existing approval for one feedstock and process does not automatically qualify a new biomass-derived intermediate or a different production pathway. The company must establish the applicable approval route and generate the necessary evidence for its own fuel.

That is another reason the renewable diesel-first strategy matters: it provides a potential commercial destination for the technology while the aviation qualification process proceeds, and it offers an opportunity to demonstrate the economics of the integrated process before committing to a full-scale SAF project.

The clock, however, is still running. For a project facing a financing deadline next year, a technology targeting aviation deployment in 2030 may not arrive in time. For a developer planning its next generation of facilities, however, the proposed process could provide an alternative worth examining. Whether it reaches our particular heroine in time remains an open question.

The supporting cast: Partners, projects, and the capital-light strategy

Our heroine may be waiting for a technological rescue, but the hero cannot build a renewable fuels industry alone. Even a successful conversion technology needs feedstock suppliers, engineering partners, project developers, customers, and capital. Haffner has been assembling a network intended to address those requirements.

In June 2024, the company announced a Paris-Vatry SAF project with LanzaJet, bringing together Haffner’s biomass-conversion capabilities and LanzaJet’s alcohol-to-jet technology. In September 2024, Haffner created SAF Zero as a dedicated vehicle for its SAF development activities. And in January 2025, the company announced work with LanzaTech and LanzaJet to explore integrated biomass-to-SAF pathways. These earlier initiatives remain distinct from the newly announced SB-HEFA process, but they illustrate the company’s broader strategy: use its core biomass-conversion capabilities in combination with complementary technologies and industrial partners.

In Canada, Haffner is also developing multi-energy hub concepts with Mundi Énergies, with renewable diesel produced through SB-HEFA identified as a potential component.

For SB-HEFA, the company’s proposed commercialization model combines equipment sales with technology licensing. The idea is to enable project developers and industrial partners to deploy Haffner’s technology without requiring Haffner itself to finance and own every production facility. That could allow the company to participate in multiple projects while limiting the demands on its own balance sheet.

The company’s financial comparison is noteworthy: Haffner estimates that €1 million in licensing revenue could generate an EBITDA contribution equivalent to approximately €3 million in equipment sales. For a technology developer, the attraction is apparent.

For a project developer, however, the financing question remains. A licensing model may reduce the technology provider’s capital requirements, but it does not eliminate the capital required to build the plant. Someone must still finance the equipment, construction, working capital, and commissioning. Someone must establish that the technology will perform as promised and that the resulting fuel can be sold at a price sufficient to service the debt and reward the equity investors.

That is where successful industrial demonstration, reliable performance data, and credible operating-cost estimates become essential. The licensing model can help Haffner scale its business; the industrial demonstration must help establish whether its customers can scale theirs.

The ticking clock: Can the rescue arrive in time?

And now we return to the railroad tracks. Our heroine has been waiting for a new set of economics. Haffner has arrived with a potentially important technological alternative. But the locomotive is still approaching.

A SAF project facing a financing deadline in the next several months cannot necessarily wait for a new technology to complete industrial demonstration in 2027 or 2028, followed by aviation-fuel qualification and subsequent commercial deployment. Nor can a developer simply substitute a new conversion process into an existing project without reconsidering its feedstock contracts, plant design, permits, construction budget, operating assumptions, and financing arrangements. For some projects, the window for such a change may already have closed.

For others, especially developments that have not yet committed to a particular technology or reached final investment decision, SB-HEFA could eventually provide an additional option. And for a future generation of projects, the implications could be more substantial.

If the technology can deliver its proposed economics, it may allow developers to reconsider what kinds of feedstocks, plant configurations, and locations make commercial sense. A project that previously required access to a limited supply of waste oils might instead be designed around a regional supply of qualifying forestry or agricultural residues. A facility whose conventional biomass-to-liquids configuration required too much capital might be reconsidered using a different conversion chain. A project that could not support its debt at the projected cost of production might become more attractive if its feedstock, capital, and operating costs could be reduced sufficiently.

But the word if is doing important work here. Haffner’s announcement identifies a potential solution to two of the industry’s central economic problems, but it does not yet establish that the solution can be deployed at the scale, cost, and timetable required by a particular SAF project.

What must happen next?

The industrial demonstration will need to establish several things. First, Haffner must show that its thermolysis process can consistently produce a suitable liquid intermediate from the intended range of biomass feedstocks. Second, the company must demonstrate that this intermediate can be upgraded efficiently into finished hydrocarbons, with acceptable hydrogen consumption, catalyst performance, product yields, and operating reliability. Third, the complete plant must establish the capital and operating costs required to support the proposed commercial economics. And fourth, for SAF, the company must complete the applicable aviation-fuel qualification process and establish a commercially viable route to producing approved fuel.

These are not minor details; they are the difference between an attractive technological proposition and an investable industrial project.

There is also the matter of feedstock sustainability. An expanded biomass feedstock base is valuable only to the extent that the material can be sourced sustainably, meets applicable regulatory requirements, and can be delivered to production facilities at the cost and volume assumed in the business plan. Low-cost biomass on paper is not necessarily low-cost biomass at the plant gate.

For Haffner, these are the questions that will determine whether the proposed shortcut through the chemistry becomes a shortcut through the economics. For the SAF industry, the stakes are larger. The next generation of projects needs more than new technology announcements—it needs technologies that can demonstrate a credible route to affordable production and attract the capital required to build commercial facilities. The opportunity is substantial. So is the remaining work.

The final reel: Will the switch be thrown in time?

In the old Hollywood serials, the hero always arrived in time. The audience knew that. What kept them coming back was discovering how he would do it. Would he leap from his horse onto the locomotive? Cut the ropes with a pocketknife? Throw the railroad switch at the last possible moment?

Industrial technology offers no such guarantees. Haffner has proposed a route around two of the largest obstacles facing sustainable aviation fuel: the cost and availability of feedstocks, and the capital required to turn them into finished fuel.

Instead of accepting the limited supply of conventional HEFA feedstocks, the company proposes to draw on a much larger reservoir of solid biomass residues. Instead of taking the conventional synthesis-gas detour, it proposes to recover a liquid intermediate directly from thermolysis and upgrade it into renewable hydrocarbons. And instead of accepting the existing cost structure, it is targeting a substantial reduction in the cost of production.

If the company can deliver those results at commercial scale, it could change the economics of a future generation of renewable fuels projects. But the industrial demonstrator is still ahead. The aviation qualification work remains to be completed. And the financing decisions confronting today’s project developers will not wait indefinitely.

The train is coming. The ropes are still holding. And somewhere in France, an engineer has his hand on the railroad switch.

TO BE CONTINUED.

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