United Airlines set to start using low-carbon jet fuel at O’Hare airport

Some flights from a major U.S. airport are about to get a little bit cleaner.

Last week, United Airlines announced it’s purchasing up to 1 million gallons of sustainable aviation fuel (SAF) from Neste, a major producer of the fuel, to use at Chicago O’Hare International Airport through the end of 2024.

With the initial batch of SAF expected to arrive this month, United will soon become the first airline to regularly use the lower-carbon jet fuel in its plane engines at a U.S. airport outside California — an indicator that SAF is starting to gain ground.

Thanks to the deal, SAF is expected to make up 3 percent of United’s total fuel usage at O’Hare by the end of the year, a United Airlines spokesperson told Canary Media. The representative declined to comment on whether United has immediate plans to expand its SAF deal at O’Hare or sign similar agreements at other U.S. airports.

Burning jet fuel accounts for 2 percent of the world’s energy-related carbon dioxide emissions. United’s introduction of lower-carbon SAF to its operations at O’Hare, a hub for U.S. air travel, marks an early but meaningful step toward cleaning up those emissions.

It may be a sign that the market for SAF is ​“slowly being made,” which could potentially create a ​“domino effect” for other major airlines to begin regularly using low-carbon fuels in their U.S. operations, according to Sarah Wilkin, the founder and CEO of Fly Green Alliance, a consultancy that aims to decarbonize air travel.

“What we hope it means is it’s becoming business as usual,” Wilkin told Canary Media regarding United’s deal. ​“It builds awareness and brings some commitment to aviation’s net-zero targets.”

SAF is a broad category that encompasses lower-carbon fuels made from biomass, like cornstalks and forest residuals, as well as from hydrogen and captured carbon dioxide. Today, most of it is derived from used cooking oil and animal fat waste collected from kitchens — including the Neste-produced fuel United will soon use at O’Hare.

The alternative fuel’s impact on emissions depends on how it is produced and how much of it is ultimately used in flight. Today, SAF is usually blended with traditional petroleum-based fuels and dropped into existing plane engines. Neste claims its SAF can reduce the life-cycle emissions of a flight by up to 80 percent.

In total, 24.5 million gallons of SAF were used in the U.S. in 2023 — much more than the year before, but a small amount compared with the overall U.S. jet fuel use of approximately 69.3 million gallons every day.

Still, SAF is picking up steam. In late July, JetBlue announced a commercial agreement with Valero Energy to receive its first regular supply of blended SAF at John F. Kennedy International Airport in New York later this year. The deal seeks to bring at least 1 million gallons of the fuel to JFK, with an option of buying an additional 4 million gallons over a span of 12 months. On top of that, Virgin Atlantic last year completed the first international flight powered entirely by SAF, a journey from London Heathrow to New York City’s JFK.

United has been ramping up its SAF efforts in recent years.

In December 2021, United flew more than 100 travelers from Chicago O’Hare to Reagan National Airport in Washington, D.C., using 100 percent kerosene-free SAF — it claims this was the first passenger flight powered by SAF alone.

A few months later, United agreed to purchase up to $52.2 million of SAF from Neste over the next three years for flights at Amsterdam’s Schiphol Airport and ​“potentially more airports,” like O’Hare. The following year, United announced it would start using SAF in flights departing from San Francisco International Airport and London Heathrow, putting the airline on track to burn 10 million gallons of SAF by the end of 2023.

Looking ahead, state and federal subsidies for low-carbon jet fuel could help the airline continue expanding its SAF efforts at O’Hare, according to a spokesperson. United is combining Illinois’ SAF tax credits with federal incentives from the Inflation Reduction Act.

Still, the fuel remains more expensive than conventional jet fuel, and supplies are limited. Further adoption is also held back by regulation. One example is the ASTM D7566, a voluntary global jet fuel standard that restricts airlines from using a fuel blend composed of more than 50 percent SAF to ensure compatibility with existing jet infrastructure.

Ultimately, despite United’s progress on adopting low-carbon fuels, only 0.1 percent of its overall fuel use currently comes from SAF, according to the company.

In other words, as Wilkin put it, ​“there’s still a long way to go.”