At a steel mill outside Beijing, reactors attached to the building capture emissions from the factory. Those waste gases can then be turned into fuel. LanzaTech, a biotech startup that designed a way to turn those emissions into ethanol, recently blended that ethanol into jet fuel that powered a Virgin Atlantic flight from Orlando to London.
The jet fuel–with a carbon footprint smaller than regular fuel, but a comparable cost–is one way that the airline industry can begin to tackle its climate problem. In 2017, flights produced 859 million metric tons of CO2. By midcentury, like other industries, airlines will have to reach net zero emissions for the world to stay on track to meet the goals of the Paris climate agreement.
For short flights, airlines can begin to shift to electric planes. Eviation, one startup with an all-electric nine-seater airplane, plans to begin making its first commuter flights in 2021. Zunum, which designed a hybrid-electric plane, plans to be in the air in 2022. Others are also on the way.
“We do see an electric plane for short distances,” says Sophia Mendelsohn, the head of sustainability and environmental social governance for JetBlue. The company’s venture arm invested in Zunum in 2017. But electric technology likely isn’t in the near future for larger, longer flights. “It’s physics,” she says. “It’s going to work for a certain amount of energy. After a certain amount of energy, the battery won’t be worth putting up in the air.”
For most flights, the industry is beginning to turn to new fuels. In September, JetBlue made its first flight using a renewable blend fuel. Though chemically identical to regular jet fuel, 15.5% of it came from used cooking oil from restaurants, which otherwise would have been wasted. Next year, the airline will begin buying around 33 million gallons of biofuel a year, or about 20% of the fuel it uses annually at JFK.
A few days before JetBlue’s first biofuel flight, United flew a 787 from San Francisco to Zurich with a fuel made partly from a mustard seed-based biofuel (for now, all of these fuels are blends for safety reasons, though fuels that use no fossil ingredients may be possible in the future). United isn’t new to biofuels–it made its first test flight with a biofuel in 2009, and since 2016, has been making regularly scheduled flights from LAX using fuel from World Energy, an L.A.-based startup that turns agricultural waste into biofuel.
United is now working to scale up its use of biofuels and synthetic fuels. “Supply is definitely a challenge,” says Aaron Robinson, senior manager for environmental strategy and sustainability at United. “If we went out to the market and said, ‘Hey, we want to buy some more biofuels for aviation’ today, there just isn’t supply for us to buy. That is part of why United has been investing early to get these companies off the ground–to make a commitment not only on paper, but in dollars, to bringing these companies to fruition.”
Fulcrum BioEnergy, one of the companies that United invested in, broke ground on a new plant in May in Reno that turns household waste into a liquid fuel. By 2020, the plant will produce 10.5 million gallons of fuel a year. “The interesting part about Fulcrum is by using municipal solid waste, you’re also reducing methane emissions because that waste isn’t ending up in a landfill to sit there for millennia,” says Robinson. Methane, which is produced by food as it decomposes (and other natural sources), is 84 times more potent than CO2.
Some airlines may soon also begin using synthetic fuel made from CO2 pulled directly from the atmosphere. Carbon Engineering, one startup in the new “direct air capture” industry, is raising funds for its first commercial plant, which will capture carbon from the air to make a fuel that the company says will be able to compete with regular jet fuel on cost in some markets that have policies in place to support technology with lower carbon emissions. Eventually, the fuel could be competitive everywhere. “They could capture carbon from the air, and if there was cheap renewable electricity [to run their plants], one could imagine that they could have a product that could be close to cost parity or cost-competitive over the long term,” says Adam Klauber, a principal at the nonprofit Rocky Mountain Institute.
All of these fuels can be used in planes without any changes in the current system. “We don’t have to modify our engines, we don’t have to change the planes, we don’t have to change the infrastructure at the airport to use this biofuel, which makes it a lot easier to implement as well,” Robinson says. “These biofuel producers just become another fuel supplier for the airlines.”
It’s a positive direction–but there’s still a very long way for the industry to go. United uses more biofuel than any other airline. But the over 1 million gallons it uses annually is only 1% of its overall fuel use. World Energy, its supplier in Los Angeles, is still the only major producer of its kind in the world. Fulcrum, the company that will make jet fuel from household waste, will supply United with nearly 10 billion gallons of fuel over 10 years, but hasn’t yet started production. Right now, state and local incentives and the market also mean that fuel producers can make more money supplying diesel to trucks rather than jet fuel to airlines.
According to one industry report, Klauber says, the world would need to add a significant number of commercial-scale plants making alternative fuel every year, from 2020 to 2050, to meet carbon goals. Until 2035, that number of new plants might need to be as high as 328 annually. Right now, only around 20 are in planning, and some of those are years from breaking ground. “What this is suggestive of is that the private sector and investment community alone are unlikely to mobilize the capital necessary to make those investments,” he says. Support from the public sector could help, similar to grants from the Department of Energy that helped Fulcrum get off the ground in Nevada. “We obviously need to see much more than that.”
Most alternative fuels also need to come down much more in cost. “We see this as a chicken-and-egg problem,” says Mendelsohn. “The customer on our flight to Disneyworld [is] saying, we want to fly on a fuel that puts less emissions into the air. At the same time, the customer is going to select a ticket largely based on price, so we need that fuel to be flying the customer in something that’s price-comparable to fossil fuel. Well, fossil fuels have been around for 150 years. That’s a 150-year jump-start on infrastructure, subsidies…that renewable jet fuel is trying to leapfrog in five years.”
Airlines will also have to make other changes, Klauber says, likely including significant changes in the design of planes, such as manta-ray-like “blended wing” designs that combine the body and wings to make a plane more efficient. “It would radically change the way aircraft are produced and require investment and new production capabilities and processes,” he says. But radical change is possible. A recent report created by the Energy Transitions Commission found that airlines, along with other industries that have particularly difficult climate challenges, can feasibly reach net zero emissions by the middle of the century.