The SAF Approach

October 19, 2025

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by Caitlin Scheresky (Biomass Magazine) ... Bio-oil SAF, commonly known as hydrotreated esters and fatty acids (HEFA) technology, currently dominates SAF production simply because it’s been proven at a commercial scale. However, HEFA technology is far from the perfect solution. While it is a sustainable, scalable and deeply researched practice, its feedstock is limited in supply. “SAF mandates require that your feedstock is sustainable, which means that you cannot use a vegetable oil because it is a food crop,” (Lux Principal Analyst Runeel) Daliah said. “The only feedstock you can use with this technology is waste oil, like used cooking oil (UCO) or animal fats, for example. And unfortunately, there simply isn’t enough waste feedstock around the world to meet the demand of the aviation sector.”

This limitation opens the door to new SAF technologies, including the biomass-to-SAF pathway, which converts biobased feedstocks into SAF. “There are two ways to do so,” he said. “The main approach is to gasify the biomass into syngas and then feed the syngas into a Fischer-Tropsch (FT) reactor. Or, the more early-stage approach is known as pyrolysis or liquefaction, where you take the biomass, heat it up in the absence of oxygen in order to liquefy it, and then refine that biocrude into aviation fuel,” he said.

Biomass-to-SAF production remedies the shortcomings faced by HEFA technology but has a few shortcomings of its own. Biobased feedstocks are both sustainable and abundant worldwide in the form of forestry and agricultural waste. However, the technology itself is underdeveloped. “Despite FT technology having been around for many years for the oil and gas industry, the technology has not yet been scaled for the SAF sector,” Daliah pointed out. “And also, to convert biomass into aviation fuel, you first need to gasify it ... [and gasification] hasn’t been successful yet for the production of liquid fuel.” Combined with a lack of experienced developers, biomass-based SAF production has a long way to go before it contends with HEFA-to-SAF production.

Ethanol-to-SAF offers another potential pathway to relieve the pressure on bio-oil-based SAF. Ethanol-to-jet (ETJ) is a three-step pathway that dehydrates the ethanol to ethylene and converts it into fuel fractions. “Ethanol is a bit unique ... when it comes to the feedstock,” Daliah said. “Now, in the EU and the U.K., the SAF mandates prohibit the use of food crops, which includes first-generation (1G) ethanol—ethanol from corn, or ethanol from sugar cane, for example.” The alternative, second-generation (2G) ethanol, is biomass-derived ethanol, of which the technology is currently in development.

This ban on 1G ethanol is limited to the EU and U.K., so countries like the U.S. and regions expected to join the SAF mandate influx like Asia and Brazil can still utilize this pathway, so long as producers can meet low CI scores. For this reason, ETJ is in a bit of a gray area as well. Where 1G ethanol is widely available but unsustainable as a food crop, 2G ethanol is limited in availability but has a much lower CI score. Technologies vary in development, but multiple experienced developers have stakes in the game, so it’s safe to say that this technology isn’t out of the race, according to Daliah.

CO2-to-SAF, or e-fuel, shares FT technology as its major pathway to production, through which CO2 and green hydrogen are combined and converted to syngas, then fed to FT reactors to produce fuels. A secondary methanol-to-jet (MTJ) pathway is emerging, through which CO2 and hydrogen are converted to methanol and then into jet fuel.

“[CO2 and green hydrogen] are theoretically very abundant as well as sustainable,” Daliah explained. “The other big advantage in this pathway is the number and experience of the developers of companies in the space.” However, the available technologies are still emerging and not at scale, respectively.

Cost of Doing Business
Each of the four available pathways have their pros and cons, but how do they hold up economically? Daliah presented the cost of SAF production compared to the current average cost of fossil jet fuel. Fossil jet fuel currently sells at a rate of $600 per ton. Even in the best-case scenario, Daliah explained, the cost of SAF cannot match the cost of fossil jet fuel—in fact, most alternatives will face a premium. The reason? The price of the feedstock. “In this case, the big challenge is how to bring the costs down,” Daliah said.

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While the pressure is on for the EU’s SAF mandate—which Daliah predicts to be scrapped, based on production costs—the sheer number of opportunities for innovation across pathways, the wide-reaching promise of HEFA and bio-based SAF, and dedication to lower the aviation industry’s carbon intensity will bring on SAF implementation. Persistence, he finished, is key to the industry’s success.

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Corn’s New Flight Path (Seed World)

Excerpt from Seed World: Ethanol’s next chapter could power the planes of tomorrow — but only if carbon-smart farming and flexible policy take off together.

Corn may soon fuel more than cars. With airlines under pressure to decarbonize, ethanol is emerging as a promising source for sustainable aviation fuel. The technology is ready, the chemistry is proven, and the market potential is massive — but policy and timing could determine whether American farmers lead or get left behind.

The Inflation Reduction Act created the 45Z clean fuel production tax credit to reward fuels with low carbon intensity (CI) scores. The lower the score, the greater the credit. That simple equation could spark a new carbon race across agriculture, with every decision — from seed selection to nitrogen efficiency — influencing a farmer’s bottom line.

Kansas Corn’s director of policy and economics Taylor Williamson recently spoke on the topic at the American Seed Trade Association (ASTA) Forage, Turf and Conservation Seed Conference in Kansas City. He explains that race is already underway, but the rules are still unclear. He says the government’s delay in finalizing the 45Z regulations is putting growers at a disadvantage.

“If Treasury doesn’t get these rules out soon, it’ll be too late for the 2026 crop,” Williamson says. “Once the seed is in the ground, it’s too late to change your CI score.”

He believes the program could be a powerful tool to inject dollars into the ag economy if it’s rolled out in time for farmers to respond.

“This is one way to put cash into the ag economy during a time of really bad prices,” he says. “The program already exists. It just needs rules and regulations.”

From Field to Flight

Ethanol already makes up about one-third of Kansas corn’s market, but the sustainable aviation fuel (SAF) pathway could push demand to new heights. Even a small percentage of global jet fuel made from ethanol would have ripple effects across the grain economy.

Williamson breaks it down simply. If SAF could become 1% of the world’s aviation fuel, and 1%of that came from ethanol-based SAF, that would use about 5.6 million bushels of corn — roughly 10% of Kansas’ annual production. Push SAF to 10% of global aviation fuel, and even if only 1% of that is ethanol-based SAF, the number jumps to 56 million bushels.

“If an airport like Dallas–Fort Worth International Airport converted half its jet fuel to SAF made from ethanol, that’s 389 million bushels,” he says. “That’s why we’re paying attention.” “Similarly, if 10% of global aviation fuel were SAF, and 1% of that came from ethanol-to-SAF, you’d get to 56 million bushels. But when we talk about a scenario like DFW, we’re assuming a full 50% SAF made purely from ethanol.”

He says the potential for ethanol-to-jet-fuel production not only strengthens corn markets but creates a symbiotic relationship with the livestock industry. Ethanol’s byproduct remains feed grain, keeping value cycling through rural economies.

“There’s not enough used cooking oil in the world to fuel every plane,” Williamson says. “If we want real sustainable aviation fuel, ethanol has to be part of the solution.”

Flexibility Over Mandates

To qualify for the highest 45Z credits, farmers may need to meet specific carbon-reduction standards based on production practices. That could include adopting no-till, planting cover crops, or switching to enhanced nitrogen fertilizers. Williamson says the intent is good, but the approach risks being too rigid.

“Don’t tell us exactly how to do it,” he says. “Just give us a number, give us the data, and we’ll go do it.”

He says although Kansas is known as The Wheat State, its plentiful corn farmers know better than anyone that what works in one field may fail in another. Eastern Kansas often benefits from cover crops that improve soil health and water retention. Western Kansas, with half the rainfall, can’t often afford to sacrifice moisture to a cover crop stand.

“Cover crops work in some places and not in others — and that’s okay,” he says. “Not all farmers, especially in Kansas, farm the same way.”

Williamson argues that flexibility, not prescription, will determine whether the program succeeds.

“You can’t accomplish your goal unless farmers can make it work for their bottom line,” he says.

Seeds of a Low-Carbon Future

The carbon-intensity push is already influencing conversations far beyond ethanol. Seed developers are exploring hybrids with better nitrogen efficiency and improved residue management. Agronomy teams are looking at how microbial products, stabilizers, and data analytics can cut emissions. Ethanol plants are developing traceability systems to verify the carbon profile of each bushel they buy.

Williamson sees this as a defining moment for the seed value chain — a chance to link genetics, agronomy, and markets in a measurable way. He believes farmers are ready to adapt, as long as risk and reward are balanced.

“Farmers aren’t afraid to innovate,” he says. “They just need to know a government program won’t put them out of business if they take a chance.”

For now, he says everyone is waiting on Washington. The potential for ethanol to power the planes of tomorrow — and for farmers to get paid for lowering carbon — hinges on clarity that hasn’t yet landed. READ MORE

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vegetable oils used cooking oil (UCO) UK (United Kingdom) Treasury Department Transportation Fuels Policy syngas (synthesis gas) Regulations-Federal pyrolysis precursors/biointermediates Methanol-to-Jet (MTJ-SPK) market forces liquefaction Kansas Jetfuel (Sustainable Aviation Fuel (SAF)) Investing HEFA (Hydro-processed esters and fatty acids) gasification forest residue/waste Fischer-Tropsch/FT farmers European Union (EU) ethylene environmental policy electrofuels (e-fuels) corn/maize conversion technology Carbon Dioxide (CO2) Brazil BioRefineries/Renewable Fuel Production Biocrude/Green Crude/SynCrude bio-oil/pyrolysis oil Aviation Fuel/Sustainable Aviation Fuel (SAF) aviation fuel (SAF) price aviation fuel (SAF) mandates Asia animal fat alcohol-to-jet (ATJ)/ethanol-to-jet (ETJ) Agricultural waste/residue 45Z Clean Fuel Production Tax Credit 2nd generation biofuels cover crops

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