United Airlines wants passengers to fly on jets fueled by old socks, rancid pistachio shells and leftover french fry oil, rather than petroleum. And it is asking them for a little cash to help the effort.
Late last month, the airline launched its Sustainable Flight Fund, a $100 million effort to power airplanes with waste from a variety of sources, such as cooking oil, crops, algae and anything that can safely be refined into jet fuel. In a YouTube video, United delivered its sales pitch via Oscar the Grouch of "Sesame Street."
The puppet's message: "Trash could be used for good."
To get there, it is working alongside Air Canada, Boeing, GE Aerospace, JPMorgan Chase and Honeywell to create a supply chain of sustainable fuel they are betting will save the industry in the era of climate change.
And they are looking for one more critical investor: the flying public.
United is giving customers the option to contribute to its fund -- at levels of $1, $3.50 or $7 -- every time they buy a ticket. The airline says it is offering flyers a way to finance a climate solution.
HOW IT WORKS
Analysts believe sustainable aviation fuel, or SAF, is the most promising way for the aviation industry to replace fossil fuels in aircraft.
So far, there is no good way to reduce aviation emissions. The industry currently is responsible for about 4% of global warming. And its emissions are expected to more than double as passengers jump on cheap flights, especially in countries that did not have them, the World Economic Forum estimates.
But many carbon offsets sold by the airline industry do not deliver on their promise, according to investigations by Greenpeace, Carbon Market Watch and others. Aircraft efficiency gains have been eclipsed by more air travel. And while companies are testing planes that run on clean electricity or hydrogen, replacing the entire commercial fleet likely will take decades.
SAF, however, is billed as a "drop-in" replacement fuel. Jet engines need no modifications to burn it. It can come from cooking oil, corn, soybeans, algae, wood and even cities' solid waste streams. Refineries turn this organic matter into a fuel by heating it up and then removing impurities. The product is virtually identical to the kerosene now used as jet fuel. Depending on the source, SAF can reduce net emissions from aviation by more than 85% compared with petroleum.
The Energy Department says it is the best option on the table to reach the country's goal for net-zero emissions by 2050.
"To meet decarbonization goals we have tied to aviation," says Valerie Sarisky-Reed, who leads the Energy Department's Bioenergy Technologies Office, "it is essential to ramp up production of sustainable aviation fuel."
Already, anyone on a United flight leaving Los Angeles International Airport soars aloft on a little bit of french fry oil. It is not much: about 20 gallons of SAF per flight in 2022. But the airport is one of only a few in the world to refuel aircraft with SAF. Since 2016, more than 60 billion passenger miles on United flights have flown on the fuel.
The supply is severely limited. Almost all SAF today is sourced from food waste -- mostly fats, oils and grease collected from restaurants and industrial kitchens. With only a few refiners in the United States, the total supply amounts to about 15 million gallons or less than 0.1% of the fuel burned by the aviation industry annually. Most of this is snapped up by large corporate customers such as FedEx, Microsoft and others to address emissions from business travel.
In addition, SAF remains two to four times as expensive as conventional jet fuel. That added cost is estimated to raise the price of a flight across the country by more than $100. Simply charging more is not possible in the cutthroat commercial aviation industry: Most Americans are unwilling to pay more to fly on their preferred airline or to even escape a middle seat, analysts say, let alone pay for their carbon emissions.
To lower SAF prices, the Energy Department and other federal agencies want to scale up the industry. They have set a national goal of producing 3 billion gallons of SAF per year by 2030 and 35 billion gallons by midcentury, enough to meet all expected U.S. demand. The Biden administration also promises $4 billion in federal backing to support aviation fuel projects and fuel producers over the coming years.
The aviation industry has been slow to invest in this vision, says Jo Dardenne, aviation director of the European nonprofit Transport & Environment. Most airlines have yet to place firm orders at viable prices, so SAF producers have not invested in enough new capacity or research into sustainable feedstocks.
So far, United says it has 3 billion gallons of advance orders for SAF, the most of any airline. The Sustainable Flight Fund will back fuel producers and purchase agreements for billions of additional gallons of SAF over the coming years.
Eventually, United wants to move beyond biofuel and generate SAF from electricity, a power-to-liquids process that pulls carbon straight out of the air. The goal is to reduce emissions 100% by 2050 without relying on traditional carbon offsets.
"SAF is the solution that will decarbonize aviation," says Lauren Riley, United's chief sustainability officer. "The supply doesn't really exist. We're just behind the curve."
But it will take more than a few extra dollars per passenger to transition to SAF. The International Civil Aviation Organization -- the U.N. agency that coordinates international air travel -- puts the global cost at $121 billion per year until 2050 to switch to sustainable fuels and make efficiency improvements.