On 18 August 2026, thyssenkrupp marked ten years of its Carbon2Chem® research platform with a line that deserves more attention than it received: the green light has been given for the construction of a plant in Duisburg that will produce Sustainable Aviation Fuel (SAF) from steel-mill gases. The carbon comes from the blast furnace. The route runs through methanol. The product is meant to end up in an aircraft wing tank.
It is a genuinely interesting piece of engineering and a genuinely awkward piece of carbon accounting, and the two cannot be separated. What follows is an attempt to hold both in view.
Ten years of turning waste gas into feedstock
Carbon2Chem started in 2016 with the groundbreaking ceremony for a technical centre next to the Duisburg steelworks, and a premise that sounded eccentric at the time: treat the gases coming off a blast furnace not as emissions to be scrubbed, but as a chemical feedstock. Coke-oven gas, blast-furnace top gas and converter gas together contain carbon, hydrogen and nitrogen. Add electrolytic H₂ and the mixture can be pushed towards methanol, ammonia and synthetic fuels.
Over ten years the project has grown into a cross-industry research platform with more than twenty partners from industry and academia, among them the Max Planck Institute for Chemical Energy Conversion and the Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT, funded by the German Federal Ministry of Research, Technology and Aerospace. The technical centre has served as the bridge between basic research and industrial application, testing individual process steps under real conditions — which matters more than it sounds, because catalyst poisons in genuine, variable metallurgical gas are what kill this kind of process in practice.
Matthias Kammel, Managing Director of thyssenkrupp Carbon2Chem, describes the founding vision as viewing CO₂ and the other components of blast-furnace gases not as waste but as raw materials, used to close carbon cycles and link steel production, the energy sector and the chemical industry. On the evidence of ten years, that claim stands up.
Why the methanol-to-jet route is suddenly viable
Methanol is a convenient molecule to make and an inconvenient one to fly on. Getting from methanol to certified jet fuel means converting it to olefins, oligomerising those into longer chains and hydrogenating the result — and then, crucially, persuading the standards bodies that the outcome is safe.
That last step was cleared this summer. On 30 July 2026, methanol was added as an approved feedstock under Annex A5 (Alcohol-to-Jet) of ASTM D7566, permitting blends of up to 50 per cent with conventional kerosene. Until then, every methanol-to-jet project in the world was building towards a specification that did not yet exist. The timing of thyssenkrupp’s announcement three weeks later is unlikely to be coincidental.
Readers of this blog will recognise the route. It is the same chemistry that SPIN member Paul Scherrer Institute and Zurich-based Metafuels demonstrated when aerobrew went into operation in Villigen in August — the world’s first plant to run the complete methanol-to-jet chain under one roof. What differs between Villigen and Duisburg is not the chemistry. It is where the carbon comes from.
The carbon question, honestly stated
The carbon in blast-furnace gas originates in metallurgical coke. It is fossil carbon. This is the point at which a certain kind of commentary declares the whole exercise greenwashing, and that reflex is wrong — but so is the opposite reflex of calling the output climate-neutral without qualification.
One condition remains non-negotiable from a Power-to-X perspective: e-SAF only makes climate sense when the carbon it contains is recycled CO₂ from biogenic, atmospheric or industrial sources, and when that recycling displaces fossil carbon instead of providing a reason to burn more of it. Industrial point sources are legitimate. A steel mill that exists anyway, producing gases that would otherwise be flared or burnt for process heat, is a defensible source of recycled CO₂. The carbon does one more useful job before it reaches the atmosphere, and a tonne of fossil kerosene stays in the ground.
The condition bites at the other end of the sentence. If the value of the gas stream became a reason to keep blast furnaces running longer than they otherwise would, the logic inverts. That is the question worth putting to any steel-gas project, and it is worth noting that thyssenkrupp Steel is simultaneously building a direct-reduction plant on the same site. The feedstock this SAF plant is designed around is, by the company’s own transformation plan, a diminishing resource.
RFNBO, recycled carbon fuel, or neither
European law draws a line that the chemistry does not. A fuel made with renewable electrolytic hydrogen may qualify as a Renewable Fuel of Non-Biological Origin (RFNBO) — the category that counts towards the synthetic aviation fuel sub-mandate under ReFuelEU Aviation. A fuel built on fossil process carbon may instead fall under the separate heading of recycled carbon fuel, which does not count towards that sub-mandate and which Member States may choose not to count at all.
Which category the Duisburg output lands in is genuinely open, not merely undisclosed. It depends on the hydrogen supply, on how the carbon is attributed and on how the delegated acts are applied to a gas stream that mixes CO, CO₂ and H₂ from three different furnaces. There is also a clock: under the current rules, CO₂ from industrial point sources remains eligible only until 2041, and from electricity generation until 2036. For an asset with a thirty-year design life, that is not a distant technicality. It is a question the financing model has to answer.
What has not been said
The announcement contains no capacity figure, no investment sum, no construction start and no commissioning date. Several trade outlets have described the facility as a pilot; thyssenkrupp itself avoids the word and speaks of translating what it has learned to an industrial scale. In parallel, a second electrolysis hall is due to be handed over to thyssenkrupp nucera next year, strengthening hydrogen supply on site and creating what the company calls an infrastructural prerequisite for continuous industrial operation.
Context matters for how much weight to put on the timeline. thyssenkrupp Steel is in the middle of a deep restructuring, with thousands of positions being cut and the terms for its direct-reduction plant renegotiated after the hydrogen ramp-up slipped. None of that makes the SAF plant less real. It does mean that a project announced without numbers, inside a division under this much pressure, should be filed under intent rather than delivery until the figures arrive.
Why this matters in Switzerland
Since 1 January 2026, Switzerland has applied the ReFuelEU Aviation blending obligations at Zurich and Geneva through the revised CO₂ Act and CO₂ Ordinance, including the synthetic fuel sub-quota that begins in 2030. Swiss aviation now sits inside the same demand curve as the EU, which means every credible e-SAF production project in Europe is, indirectly, part of the Swiss supply picture.
Against that backdrop, the Duisburg concept invites a comparison that Swiss readers can make for themselves. SPIN member Synhelion is building towards commercial-scale solar fuels with a binding SWISS offtake agreement and a 30,000-tonne plant now in pre-FEED. Metafuels is running the same methanol-to-jet chemistry as thyssenkrupp, from a Swiss base, with a first commercial plant in Rotterdam. Both work with carbon that is biogenic or atmospheric rather than fossil, which puts them on the right side of the 2041 line without needing to argue about it.
That is not a reason to dismiss what thyssenkrupp is attempting. Recycling the carbon that European heavy industry emits today, while that industry transitions, is exactly the kind of bridge Power-to-X should be building. It is a reason to insist that the bridge is described accurately: as defossilisation of a fuel that would otherwise be entirely fossil, with a defined end date attached to its feedstock, rather than as climate-neutral flying. Fossil emissions from flying can drop close to zero on this route. Saying so precisely is what keeps the argument credible when the numbers finally do arrive.
Source: thyssenkrupp press release, 18 August 2026.
🤖 AI transparency: This text and its visual were created using AI, reviewed and approved by a human.
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