Changing climate threatens native land, people
Wildfires, drought and flash floods — all worsened by climate change — are impacting the lives and land of native people in the Southwest, including the Tewa people of New Mexico’s Kha’p’o Owingeh, also known as Santa Clara Pueblo. (Nov. 1) (AP Video: Martha Irvine, Andrés Leighton, Tammy Webber)
- More sustainable fuel sources are a key to reducing the carbon footprint of flying.
- Sustainable aviation fuel comes in many forms including plant- and cooking oil-based products.
- SAF still emits CO2 but is less carbon-intensive over its lifecycle than traditional fossil fuel.
Flying isn’t great for the environment – it’s just a fact. It is carbon-intensive to get a giant airplane off the ground and keep it in the sky for hours. But United Airlines, along with all members of the International Air Transport Association, is committed to having a carbon-neutral operation by 2050.
What sets United apart is that it has no plans to use carbon offsets – a fancy way of saying it won’t pay to plant trees and take credit for reducing emissions in that manner – on its path to getting there. Instead, the airline plans to rely heavily on sustainable aviation fuel, an alternative to traditional petroleum-based jet power that is more environmentally friendly to produce.
“United has, today, 40% of all of the announced fuel agreements for SAF globally and last year we consumed less than 0.1% of our total fuel supply as SAF, so there’s just not enough,” United Airlines’ chief sustainability officer Lauren Riley told USA TODAY.
But airlines and other industry stakeholders are committed to promoting sustainable aviation fuel as the key measure to reduce the carbon footprint of flying.
Global climate breakthrough: Here’s what you missed from COP27
“The airline industry knows it has a problem. They don’t have to be convinced. They really have only a couple of tools, they can do fuel efficacy, but they’ve been doing that for a long time,” said Julio Friedmann, chief scientist at Carbon Direct, a carbon management firm, and a former professor at Columbia University. “They can do sustainable fuels, but right now they don’t deliver in terms of carbon intensity or volume or price. They’re working on it really hard, but they’re not there.”
What is sustainable aviation fuel made of?
Sustainable aviation fuel refers to jet fuel made from sources other than traditional drilled oil.
It can be plant-based oil, recycled cooking oil, or come from a number of other sources.
“It is reprocessed waste lipids and fats. It is things like tallow and used cooking oil that gets reprocessed into a biokerosene, a jet fuel that can be blended into regular jet fuel at a ratio up to 50%,” said Samuel Engel, a vice president at the consulting firm ICF. “It has been effective, but it is limited in its scalability. You can’t fly an entire airline on French fries.”
Learn more: How do carbon offsets work?
Nathan Parker, an assistant professor at the School of Sustainability at Arizona State University, said other sustainable aviation fuel alternatives include wood-, grass- or municipal waste-based fuels, as well as other products that are still being developed.
And Riley from United said she sees great promise in evolving technology that could one day allow for the direct capture of atmospheric carbon dioxide that then gets converted into aviation fuel.
“The best SAF, that third generation is this power to liquid, where you still have the tailpipe emissions, but you’re vacuuming it out of the atmosphere to convert back into jet fuel,” she said.
Is sustainable aviation fuel actually sustainable?
It’s complicated. Even sustainable aviation fuel will emit carbon dioxide into the atmosphere as part of its combustion cycle at virtually the same rate as traditional fossil fuel. The difference from petroleum-based jet fuel, experts say, is where that carbon comes from and how quickly it can be recaptured into a new fuel source as part of the production and refining process.
“In most cases, the carbon reduction is not actually being sucked out of the atmosphere. It’s something that’s relative,” said Nik Pavlenko, fuel program lead at the International Council on Clean Transportation. “A lot of SAFs, pretty much all of them, are net emitters in absolute terms.”
Get the facts: What is global warming? Definitions explained.
Even so, Parker noted, the carbon emission and capture cycle can occur much more quickly with sustainable aviation fuel than with traditional fossil fuels.
In other words, plant-based aviation fuels (or direct carbon capture experimental fuels) offset their own carbon emissions as part of their production process. Sustainable aviation fuel production typically captures carbon that’s currently in the atmosphere. Then, the fuel itself releases carbon dioxide again during flight, but it’s recaptured when another batch of SAF is produced.
In the case of plant-based jet fuels, for example, carbon dioxide is captured during the normal plant-growing process.
One snag Parker pointed out is that municipal waste- and cooking oil-based fuels are releasing new carbon dioxide into the atmosphere, but he said it still may be more environmentally friendly than the alternatives for their disposal.
“If it goes into a landfill, it’s most likely going to end up generating landfill gas, methane,” he said.
Methane is a more potent greenhouse gas than carbon dioxide, and although it dissipates more quickly than carbon dioxide, many experts see it as relatively more environmentally friendly to use these waste products as carbon-emitting fuels, rather than letting them pump out methane from a landfill.
What accounts for sustainable aviation fuel’s reduced emissions?
Since sustainable aviation fuel still emits greenhouse gas during flights, it can be confusing to understand what actually makes it better for the environment.
“It is a lifecycle analysis,” Riley said, meaning the reduced carbon footprint from SAF doesn’t necessarily come from how it’s used, but rather how it’s produced.
“All these different fuel pathways have different upstream emissions,” Pavlenko said. “Once it’s in the plane, the emissions are the same across all pathways.”
When can I take a sustainable aviation fuel-powered flight?
It’s probably going to be a while.
“This is legitimately hard,” Friedmann said. “Still, I think we’re going to see a substantial uptick in fuel volumes, with good carbon intensities. Things like the Inflation Reduction Act have created good incentives” for sustainable aviation fuel production in the U.S.
According to Pavlenko, the European Union has committed to making 5% of the aviation fuel supply on the continent sustainable by the end of the decade and 20% by 2035.
But, he said, it will be a “steep slope” to get there.
“Absent public policy, there’s really no hope for large-scale deployment of sustainable aviation fuel. Even the cheapest one is about two times the cost of fossil fuel,” Pavlenko said. “Airlines are price sensitive … They’re not going to shift one of their biggest costs to something more expensive.”
It’s electric: New race cars are good for the environment
“We’re only slightly further along in the industry than we were 15 years ago when I started doing this,” he said. “The scale-up costs, or what I call the transition costs to these fuels is pretty significant and if it’s going to happen, you’ve got to figure out who’s going to pay for it.”
Contributing: Elizabeth Weise, USA TODAY
Visit our sponsors
Wise (formerly TransferWise) is the cheaper, easier way to send money abroad. It helps people move money quickly and easily between bank accounts in different countries. Convert 60+ currencies with ridiculously low fees - on average 7x cheaper than a bank. No hidden fees, no markup on the exchange rate, ever.