For New Electric Jet Fuel, Start Big Instead of Starting Small

Mikala Grubb, the senior vice president for all technologies at Topsoe after 19 years at the company, was asked how developers should scale up a new kind of jet fuel without taking on too much risk. The cautious playbook is familiar, start with a small demonstration plant, then build a slightly bigger pilot, then scale up step by step so the surprises stay small.

Grubb rejected it. “We would much rather go to the large scale immediately,” she said.

Her case, which she made about eSAF, a newer kind of sustainable jet fuel, is about cost. The cost of a fuel plant does not scale in a straight line, she said, so fuel from a tiny facility costs a lot more per barrel.

She pointed to plants that turn waste fats and oils into fuel for comparison. She estimated that very few of those plants are built below about 2,000 barrels daily, since below that size the math simply does not work. Financing for these newer types of projects is already a bottleneck, her interviewer said and she agreed.

That does not mean she wants to skip testing altogether. A demonstration plant built with partners in Leuna, Germany, is now under construction and is targeting 2,500 tons of eSAF in the fourth quarter of 2027, which she called an important stepping stone. But she argued that only part of the eSAF chain is truly new, while the rest rests on extremely mature technology, so a full size plant should work.

She put it this way, imagining a buyer asking for a large plant: “If somebody asked me today, ‘I would like to buy an eSAF plant of 5,000 barrels per day,’ I would be more than happy to sign it,” she said.