GE Aviation engineers fuel development of sustainable aviation fuels

The bulk of researchers working on SAF are located in region, with UD Research Institute partnering as well.

On Dec. 1, United Airlines flew a jet with more than 100 passengers from Chicago to Washington, D.C., a plane fueled by sustainable aviation fuel (SAF), marking the first commercial flight using such fuel, the airline said.

The demonstration flight on a new United 737 MAX 8 used 500 gallons of SAF in one engine and the same amount of conventional jet fuel in the other engine to “prove there are no operational differences between the two,” as United put it in a release at the time.

Most passengers weren’t immediately aware of the milestone the flight represented. But GE Aviation fuels expert Gurhan Andac — who was on the flight — was keenly aware.

“It was absolutely fantastic from beginning to end,” Andac said in an interview. “There was absolutely no difference observed by the pilots or the passengers or myself.”

Andac is among GE Aviation’s cadre of engineers and researchers developing sustainable aviation fuel, sometimes called simply “SAF.”

SAF, as the Evandlale-based aerospace company describes it, is a synthetic fuel made from any of some 60 different agricultural feedstocks — plant oils, algae, greases, fats, waste streams, alcohols, sugars, captured CO2 and more.

The fuel is borne of age-old agricultural processes — but it very much represents the future, Andac and fellow GE engineer Chris Lorence believe.

GE Aviation has researched and pursued SAF for some 15 years. Recently, however, the work has drawn new attention thanks to a recent visit to Ohio by Thomas Vilsak, the U.S. secretary of agriculture.

“It was very encouraging,” said Lorence, GE Aviation chief engineer and general manager. “I was very impressed by the secretary’s depth of knowledge and passion for the topic. It is certainly something that, I think, the public may not fully understand or appreciate.”

“We know that we have to continue to look for more ways for farmers to profit from what they do on the land,” Vilsack said, in remarks shared by GE. “And one way to do that is by converting agricultural products — agricultural waste products — into this very valuable commodity that will allow our planes to fly more environmentally friendly.”

There are more than a few differences from conventional fossil fuels, which are extracted from the ground and burned into the atmosphere.

Plants extract their own carbon dioxide from the atmosphere, Lorence said. Ordinarily, at the end of the growing season, that carbon dioxide is released back as plants decay.

Turning that feedstock into aviation fuel interrupts that process, taking those crops and transforming them into aviation fuel before they decay.

The result is fuel that is 100% suitable for aviation, GE engineers say.

“With SAF, the end product is not different,” Gurhan said. “It’s jet engine fuel.”

“What’s alternative is not the nature of the end-product, it’s where it’s coming from, the alternative feedstock,” he added. And some elements of the production process are different, as well.

But there are real challenges, both engineers acknowledge. Producing SAF is prohibitively expensive compared to fossil fuels.

The government will have to play a key role in bringing SAF to market, incentivizing development, supporting what Lorence called “the pathway from farm to fuel.”

The bulk of the GE Aviation engineers working on SAF are located here in Southwestern Ohio, with much of that work happening in partnership with the University of Dayton Research Institute, according to GE.

“We are literally daily engaged with them on that,” Gurhan said, referring to UDRI.

Steve Zabarnick, UDRI research chemist and professor, said UD has worked not only with GE Aviation but the FAA and the Air Force Research Laboratory on SAF.

“The bulk of our work is to prove the composition and the properties are exactly the same as the fuel produced from petroleum,” he said.

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