In sustainable aviation fuel production, one cost dominates all others: electrolysis alone accounts for more than half of total e-SAF expenses. That single fact has shaped years of industry debate over which production pathway could ever be efficient enough to work at commercial scale — where every kilogram of hydrogen and every megawatt of electricity must translate into the highest possible kerosene yield.
Now Europe’s largest power-to-liquid demonstration facility, backed by €130 million in German federal funding, has made its choice.
The efficiency problem at the heart of sustainable aviation fuel
Producing liquid hydrocarbons from electricity and CO2 is technically demanding — and expensive in ways that compound at scale. Electrolysis alone accounts for more than half of total e-SAF cost, which means energy efficiency isn’t simply a performance metric; it’s the economic foundation on which any viable business case must rest.
Every megawatt of electricity and every kilogram of hydrogen must translate into the highest possible kerosene yield. Pathways that lose significant energy to heat, combustion, or low-value co-products carry a structural cost disadvantage that no amount of operational optimization can correct.
The choice of production pathway sits at the center of any serious attempt to scale PtL deployment. That’s precisely why the decision made by Europe’s largest e-fuels demonstration facility carries real weight across the industry.
How G2L™ works — and why recycling changes the equation
G2L™ integrates Topsoe’s eREACT™ reverse water-gas shift reactor — electrically heated rather than combustion-fired — with Sasol’s low-temperature Fischer-Tropsch synthesis (LTFT™). Removing combustion from syngas generation improves both hydrogen and electricity efficiency from the start.
On a once-through basis, G2L™ performs comparably to competing pathways such as methanol-to-jet. The decisive advantage emerges when light hydrocarbon recycling enters the picture.
In conventional once-through operation, light ends such as naphtha are separated and sold as lower-value co-products. G2L™ reintegrates these streams alongside fresh CO2 and hydrogen, converting them into additional jet fuel — kerosene yield rises to 100% of product output, carbon efficiency stays above 95%, and naphtha recycling alone cuts electricity consumption by around 15% compared to once-through operation. In a sector where power prices dominate project economics, that reduction is anything but incidental.
Waste heat as a resource: linking Fischer-Tropsch to high-temperature electrolysis
Fischer-Tropsch synthesis is highly exothermic. That heat is unavoidable — but in G2L™, it isn’t wasted. Steam produced by the reaction operates at temperatures well-matched to Solid Oxide Electrolyser Cells (SOECs), making it possible to route process heat directly into hydrogen production and reduce the external electricity needed for electrolysis. What would otherwise be a cost-neutral byproduct becomes a genuine cost-reduction lever.
When SOEC integration is combined with naphtha recycling, total electricity demand can fall by up to one third compared with conventional alkaline electrolysis. Two of the largest cost drivers in e-SAF production — power consumption and hydrogen yield — are addressed simultaneously, through thermodynamic alignment rather than incremental optimization.
Europe’s largest PtL plant selects G2L™ — what the Leuna facility means for the sector
The Technology Platform Power-to-Liquid Fuels (TPP), operated by the German Aerospace Center (DLR) and funded with €130 million from the German Federal Ministry of Transport, will be Europe’s largest e-fuels research and demonstration facility. Its location at the established Leuna Chemical Complex in Germany provides access to existing industrial infrastructure.
Designed for a capacity of 2,500 tonnes per year of PtL fuel — primarily kerosene — the TPP uses biogenic CO2 and green hydrogen as feedstocks. Its goals extend beyond fuel production: the facility aims to de-risk the PtL route, support industrial scaling, and optimize the fuel itself, including reducing the non-CO2 climate effects associated with aviation. In 2025, Topsoe and Sasol formalized a cooperation agreement with DLR and EPC contractor Griesemann Gruppe to enable construction, operation, and R&D activities at the plant. Operations are expected to begin in Q4 2027.
From demonstration to commercialization: what comes next
For Topsoe and Sasol, the TPP represents more than a research milestone. It’s the critical step between laboratory-validated results and full commercial deployment — a real industrial environment where G2L™ will be stress-tested across the entire PtL value chain, from renewable hydrogen and biogenic CO2 through to certified e-SAF.
The process also has flexibility built in. Renewable natural gas — biomethane derived from agricultural residue, food waste, or wastewater — is identified as a compatible feedstock, broadening the range of renewable inputs G2L™ can use and potentially easing feedstock constraints as the sector scales.
If Leuna delivers on its design targets, the implications extend well beyond the facility itself. Aviation’s decarbonization pathway needs production routes that are both scalable and cost-competitive. A successful demonstration at 2,500 tonnes per year — with energy efficiency gains documented and a full certification pathway mapped — could materially accelerate commercial investment in PtL at a moment when the industry can least afford delays.
