One person traveled across the Atlantic in 1928; in 2018, there were 4.3 billion passenger journeys. Even though some Americans could avoid flying even before Covid—according to a Gallup study, roughly half of Americans don’t fly at all—the remaining Americans fly enough to raise the mean to two flights annually.
Getting people into the air requires a lot of energy, and since energy production impacts the environment, air travel is a significant source of carbon emissions, posing a particular problem compared to other forms of transportation in terms of climate change. Combustible fuel remains virtually the only method to fly, at least for longer trips, unlike advancements in electric automobiles, boats, and trains, where the increased mass required to go electric isn’t an insurmountable engineering barrier, and the extension cords aren’t 30,000 feet long. Flights of 1,000 miles or more, for which there is now no practical fuel substitute, account for 80% of emissions.
Each individual has a role to play in bringing down emissions. The average American is responsible for about 15 metric tons of CO2 per year, and more than one-third of Americans say they are now likely to pay a little extra in their airfare for carbon offsets. The rich and famous have an even bigger carbon footprint. Taylor Swift’s much-maligned private jet produces around 8000 tons of CO2 annually. But Taylor has nothing on the airline industry, whose annual CO2 emission is pushing one billion metric tons. If the combined air industry were a country with a killer peanut region, it would also have a larger CO2 emission than Germany.
However, the sector prides itself on having a low carbon footprint in comparison to other sectors.
According to the industry trade group Airlines for America, U.S. carriers move more than 2 million people and 68,000 tons of freight daily, producing “only” 2 percent of the country’s greenhouse gas emissions. With U.S. airlines increasing their fuel efficiency (on a revenue ton mile basis) by more than 135% between 1978 and 2021, the aviation sector has gotten more efficient in recent decades. However, according to climate analysts who research the aviation industry, focusing on how small that 2% number may seem is part of a developing issue.
Video conferencing may replace some portion of business travel, but as the aviation sector rebounds, climate analysts say a tripling in global air travel in the decades ahead — although forecast before Covid — is still a safe bet. Passenger travel will ramp back up more slowly, but analysts note that aviation is also used for cargo, which is not affected by business class. That’s a reason for significant concern about aviation’s carbon reduction plans. According to climate analysts, the industry needs to focus on keeping its emissions down rather than seeing its current share as a reason to move more deliberately.
Compared with autos, where there is already a decade of progress on electric vehicles, and in the power generation sector, where there have already been significant investments in renewable energy sources that are cost-competitive versus traditional sources, aviation is still in the experimentation days of new fuel technology. Electric batteries, at best, have a role to play on shorter, regional routes and urban travel, and airlines are making these investments.
Some critics say the aviation industry has been too slow to seek climate solutions but concede that aviation is a demanding sector for net-zero goals because of its unique safety and regulatory requirements. Aviation wasn’t helped by the pandemic, and its critics say that expecting the past few years to have seen a tidal wave of investment into startup technologies would have been unrealistic given the more pressing financial challenges. Airlines have completed test flights with sustainable aviation fuels, and the deals with sustainable aviation fuel producers have accumulated.
American Airlines finalized a deal over the summer with biofuel company Gevo to purchase 500 million gallons of sustainable airline fuel (SAF) over five years, part of American’s net zero carbon directive. It describes its climate goals as “aggressive,” including achieving net-zero greenhouse gas (GHG) emissions by 2050. American is the first airline globally to receive validation from the Science Based Targets initiative for its intermediate GHG emissions reduction targets and the only U.S. airline to report using more than 1 million gallons of sustainable aviation fuel in 2021.
The beginning of Gevo’s low- or zero-carbon SAF production process is the farm where the feedstock is grown. The business collaborates with farmers that employ regenerative farming methods to store carbon in the soil. To minimize their carbon footprint, these farms also apply fertilizer and pesticides with precision.
These feedstocks, such as field corn, will be used by the plants that Gevo is constructing to produce ethanol. Gevo continues the processing of ethanol to create a substance that is chemically equivalent to common aviation fuel. Standard aviation fuel and Gevo’s SAF are different in that no fossil fuels are required in the production process for heat, electricity, or any other necessary power.
To replace fossil fuels in the process, Gevo’s incorporates wind, solar, hydrogen, biogas, and other renewable energy sources. According to John Richardson, director of investor relations at Gevo, this will offer a replacement fuel for aviation requirements that is net zero, or even net negative, in terms of carbon intensity if carbon capture, utilization, and storage (CCUS) is also incorporated.
Though, unlike EVs in the auto industry, there is much discussion about which SAF approaches will ultimately win, and what tradeoffs need to be made today to support current technologies in development, SAFs are chemically identical to standard airline fuel, but their production process is significantly different (and greener) than traditional fuels.
As competing technological solutions are evaluated by the aviation industry, the scale at which feedstocks for sustainable aviation fuels are generated today is nothing near that of the production of global jet fuel. From an optics standpoint, using feedstocks from the food industry in particular could become a bigger problem in the future.
A number of climate analysts told CNBC that they are concerned about the excessive attention being paid to expanding feedstock-based sustainable jet fuels at a time when worries about global food security are growing in a world where significant impacts of climate change on agriculture are occurring.
Gevo emphasizes that it employs the plentiful and low-nutritional residual starches from “inedible field corn” as feedstock.
Judged against the standards of its own industry, American remains a leader in carbon reduction efforts. American received a CDP Climate Change score of “A–” in 2021 — the highest score among airlines in North America, and one of only two airlines globally to score that high.
“We recognize that climate change is urgent and imminent” said Jill Blickstein, vice president of sustainability at American Airlines.
“As the world’s largest airline, American is committed to developing the tools necessary to decarbonize our operations.”
In addition to Gevo, it has invested in Bill Gates’ Breakthrough Energy Catalyst, “all aimed at bringing forward the technologies that will help reach our ambitious sustainability goals,” Blickstein said.
There are multiple technological approaches to sustainable aviation fuels that can decarbonize planes without prolonging the use and dependence on current fossil fuels and green hydrogen technology just got a big boost from the Inflation Reduction Act.
More investor money is expected to flow into green hydrogen as a result of the IRA, with climate analysts describing the tax credits as being a huge driver for sustainable aviation fuels because science aside, the biggest challenge with scaling up these operations and SAF production has been the financial incentive. Green hydrogen approaches aim to remove C02 from the air and blend it with green hydrogen into a form of kerosene that can be cost competitive with convention jet fuel. In February 2021, KLM first flew a Boeing 737 passenger plane from Amsterdam to Madrid fueled with 500 liters of synthetic kerosene, from energy giant Shell, mixed with traditional jet fuel.
Recently announced deals with startups in the space were already in the works with major air carriers even before the IRA, including Twelve, which recently inked a deal with Alaska Airlines and Microsoft for its approach to create sustainable fuels using carbon captured from the air, water and renewable energy. Alaska, which has used SAF blends since 2011 on specific routes, noted itself there is a long way to go: currently less than 1% of total fuel available is SAF, and its costs is three to five times more than conventional jet fuel.
Delta Air Lines recently signed the largest U.S. aviation deal yet for green hydrogen produced fuels, with Louisiana-based DG Fuels, which uses waste CO2 as a feedstock, and in its announcement measured the scope of the challenge ahead by stating that the existing global SAF supply could operate a fleet Delta’s size for one day.
For the time being, EVs are much father along the innovation curve, with many more years of testing and government policies to support the transport sector’s transformational growth.
But not everyone sees SAFs as the solution, particularly given growth trends in the industry. At the recent Farnborough International Airshow, campaigners and climate activists pushed back against the industry’s emphasis on SAFs, urging them to “get real” and offer more significant climate solutions. Instead of SAFs, slowed growth and less travel and fewer flights is proposed as a way of addressing the issue, perhaps by reducing domestic flights and encouraging and improving rail travel.
Analysts caution that all of the effort going into aviation’s carbon-free future should not eliminate even more significant replacements for air travel, such as high-speed rail. But for aviation, the goal has to be the same as in other sectors, with its emissions peaking as soon as possible. And the choice that seems clear today is that aviation remains on the fuels pathway, unlike autos, where electric is the future. Whichever form of fuel production produces the least emissions with the greatest benefit and cost-effectiveness will win, and that’s what no player in aviation knows for certain today. Climate analysts expect it will take at least five years to a decade for the most viable solutions to emerge.
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