In-Depth
Aerospace manufacturers trying to develop sustainable jet fuel to combat climate crisis

When United Airlines flew a plane full of passengers from Chicago to Washington, D.C. on Dec. 1, it did it with one engine 100 per cent powered by fuel made from corn sugar.

It was a historic first, according to the airline. Though other international carriers — including Air Canada — have flown using a blend of traditional and renewables-based fuels, United said its use of a 100 per cent plant-based fuel developed by Virent, a subsidiary of U.S.-based Marathon Petroleum was a first for a commercial flight.

In the face of the global climate crisis, the race is on to find a way to reduce greenhouse gas emissions from the aviation sector. Around the world, scientists, technology startups and fossil fuel giants alike are battling to become the lead suppliers of what has come to be known as “sustainable aviation fuel,” or SAF.

“It’s a bit of the Wild West. You’ve got companies trying to get going, you’ve got companies maturing technologies, you’ve got technologies trying to make the leap to commercial before they’re quite ready,” said University of Alberta professor David Bressler, whose own advanced-stage research into the production of jet fuel from waste fats and oils was awarded a nearly $3-million federal grant last year.

“But eventually you’re going to see somebody emerge in this space, I’m quite confident, who has a fundamentally strong business model.”

Air travel is responsible for two per cent of global emissions, but is considered by many experts to be one of the most difficult sectors to decarbonize, as the long distances and the immense power required don’t lend themselves easily to electrification. Hydrogen-powered aircraft, too, while technically a possibility, also remain a long way from becoming a reality.

Still, the global aviation industry itself has committed to achieve net-zero carbon emissions by 2050. And with the demand for air travel expected to grow between now and then, the International Air Transport Association estimates that a “business as usual” trajectory would result in 21.2 gigatonnes of CO2 being released into the atmosphere by the aviation sector over the next 29 years. (For perspective, total global energy-related C02 emissions in 2019 were around 33 gigatonnes.)

That’s why the industry is banking on SAF. Though it doesn’t eliminate emissions, it is a lower-carbon solution that instead of petroleum, is made from renewable materials such as used cooking oils, organic municipal waste or even algae.

SAF still has a small carbon footprint that varies depending on the production method and the supply chain involved in getting it to the airport. But it can reduce carbon dioxide emissions by more than 85 per cent compared to conventional jet fuel, and it’s also a “drop-in” fuel, meaning it doesn’t require changes to aircraft or any special infrastructure at airports. The industry has set a goal of 2.5 billion gallons of SAF produced by 2025.

But there are huge challenges ahead. Sustainable aviation fuel is still very much a fledgling industry, with only about 20 million gallons produced and used on a global basis last year.

“In the U.S. alone, airlines use more than 20 billion gallons of jet fuel annually,” said Jimmy Samartzis, chief executive of LanzaJet, a technology company that uses ethanol produced from corn or sugar cane as a feedstock to produce SAF. “So there’s a lot that needs to be done to achieve the industry’s goals.”