More Electric Cars Are Key To Meeting SAF Targets, Boeing Says

FLORENCE, Italy—Aviation needs other transport sectors, particularly road transport, to accelerate the transition to electric vehicles to give the U.S. any hope of meeting its projected sustainable aviation fuel (SAF) needs, says Jim Hileman, Boeing VP and chief engineer of sustainability and future mobility.

Although SAF production is accelerating relatively quickly, the rate is inadequate, says Hileman, who joined the company in 2023 from the FAA where he was chief scientific and technical advisor for environment and energy. “There is tremendous growth happening right now. Factor two growth from 2022 to 2023; factor three growth from 2023 to 2024, but we’re starting from small numbers, and we need to grow quickly,” Hileman says. “And the truth is, it’s not growing quickly enough.”

Hileman, who was speaking at the 2024 Congress of the International Council of the Aeronautical Sciences here in Florence, echoes others who have voiced similar concerns. Late in 2023, Hemant Mistry, IATA's director for the net zero transition, said the association was “expecting significantly greater output” of SAF for 2023 and, for 2024, IATA hoped fuel producers would make available 1.5 million tons.

However, IATA estimates that the industry will need 500 million tons of SAF in 2050, 1,000 times the volume produced in 2023. To meet the recently established target of a 5% reduction in CO₂ emissions by 2030, formulated by ICAO’s Third Conference on Aviation and Alternative Fuels (CAAF/3), around 14 million tons of SAF will have to be available in 2030—essentially 10 times the amount targeted for 2024.

Such volumes are currently far from realistic, particularly in the U.S. where key biofuel feedstock such as corn is also in high demand from the ground transport sector, Hileman notes. “Everybody else wants the same basic molecules that we’re going after ... and that’s largely true of what is happening elsewhere,” Hileman says.

“The amount of electricity going to cars in the United States in 2022 was minuscule. That has to grow dramatically. If that happens, then the amount of biomass going to transportation could then go to aviation instead.”

Underlining the magnitude of the problem facing the U.S., he adds that 30% of the American corn crop goes to produce ethanol. “We can have all kinds of discussions about the sustainability of ethanol. That’s not my point here,” he says. “That results in roughly 17 billion gal. per year, which is energetically equivalent to 9 billion gal. of jet fuel. That’s 33% of the uplift of jet fuel in 2019 in the United States. That’s why it’s important that ground transportation electrifies if aviation is going to be getting large quantities of biomass. There’s just not enough biomass out there.”

“Within the United States, there is the potential for that biomass to get to 35 million gallons per year to meet the needs of the SAF grand challenge,” Hileman says, referencing the U.S. government initiative launched in 2021 to expand domestic consumption to 3 billion gallons in 2030 and 35 billion gallons in 2050 while achieving at least a 50% reduction in lifecycle greenhouse gas emissions.

“However, there’s not enough biomass to also feed every car and truck. It also means that we need to be very careful in thinking through how we use biomass, and it also means that we in aviation really would be benefit from having more discussions with other users of energy, such that we all get on a similar page.”

Referring to the multiple types of feedstocks that are available for SAF, he says: “The challenges that we have with them is related to how much environmental benefit do they give us in terms of lifecycle CO₂; how much should it cost? How much of it do we get? How much biofuel feedstock is available? And then where’s our competition? Who else is getting this stuff before us?”

Government policy is also at fault, Hileman says. “The reason those numbers are small, to be quite honest, is because all the SAF being used in the planet right now is that 98% of it is HEFA from plant oils. There are actually billions of gallons of that stuff being produced every year, but it’s all going to diesel trucks because of policy choices,” Hileman says. “That’s where it’s going right now. It’s there—it’s just not going to aviation. That’s important to know, and SAF from sugars and starches are also going to ground transportation for cars.”

“The price is also actually rather high, and so where we really need to be thinking of as an aviation industry is not necessarily the aerospace part, but the industry as a whole is thinking through, how can we bring down these prices?” he asks. 

“It’s a lot to ask for policymakers and the flying public to pick up that entire bill,” he continues. “So, can we think about where else to get these things? And so that’s a challenge that I’m going to be giving to a lot of people here and elsewhere and anywhere I get a chance.”