In 2020, Japan Airlines set a goal of reducing its net emissions of planet-warming carbon dioxide to zero by 2050. Almost five years later, during which time rival ANA Holdings announced the same target, slow progress in many areas shows just how challenging decarbonization is for the aviation sector.
Despite being one of the most carbon-intensive activities, aviation makes up a relatively small percentage of global carbon emissions at 2.5%, although it has a greater warming effect due to other emissions. But that contribution is expected to ramp up as demand for flights grows. In the case of Japan, the nation’s tourism targets tell the story: 60 million foreign tourists by 2030, up from a record of almost 37 million last year.
Both JAL and ANA are looking to a suite of technologies to preserve the social and economic benefits of aviation we currently enjoy, with domestic production of what is known as sustainable aviation fuel (SAF) set to begin in April. But each of these approaches come with significant challenges, and even these two airlines differ in the emphasis they place on them.
“A 2050 net-zero target, it does seem far away, but I think for aviation in particular, it's quite an aggressive timeline,” says Nikita Pavlenko, programs director of fuels and aviation at the International Council on Clean Transportation.
Greener fuel
Of the factors affecting how much flights warm the planet, one has remained essentially constant: the carbon intensity of fuel. Now, efforts to change that are ramping up.
SAF — biofuel made from oils and fats, municipal waste and nonfood crops but still with similar properties to conventional jet fuel — has emerged as a favorite decarbonization solution of the aviation industry. In a best-case scenario, it can cut CO2 emissions by up to 80%, although some crop-based varieties may actually increase emissions because of increased land use. Currently SAF can only comprise up to 50% of an aircraft’s fuel to ensure compatibility with all engines.
ANA has staked a lot on SAF and its equivalents, with 70% of the emissions reductions needed for net zero coming from them. JAL is less focused on such fuel, but still envisages a 45% reduction based on SAF.
Despite these targets, both airlines’ use of SAF remains extremely low.
In the fiscal 2023, which began in April of that year, JAL’s SAF use stood at 0.012%, leaving some distance to climb if it is to hit its goal of 1% in fiscal 2025 and more than 10% by fiscal 2030. ANA’s SAF use in fiscal 2023, meanwhile, was less than 0.1% — against the same 2030 target as JAL’s, with these in line with Japan’s proposed SAF mandate.
Both companies are actively working to increase those percentages, with the airlines co-establishing the Act for Sky organization to promote SAF in 2022 and building out supply chains. JAL has even set up used cooking oil collection boxes at 35 stores nationwide.
Supply of domestically produced SAF to both airlines is expected to begin in April, with Cosmo Oil Marketing planning to supply 30 million liters per year from fiscal 2025.
But a big barrier to increased adoption is cost.
“It's basically four times more expensive compared to fossil jet fuel in the case of the currently available SAF,” says Takehiro Kawahara, an aviation specialist at BloombergNEF (BNEF).
What’s more, SAF doesn’t benefit from the same “learning curves” as other green technologies — such as solar panels and batteries — under which consistent improvements in performance and reductions in cost are observed over time.
“There could be some positive impact of the scaling, but even so the cost of feedstock will not dramatically come down,” says Kawahara, pointing out that this will make up the bulk of the cost.
The feedstock could even be more expensive in the future, because of increased competition for it driven by government incentives or mandates, Kawahara adds.
That speaks to another problem: supply constraints.
“The issue for these really ambitious SAF goals,” Pavlenko notes, “is that hydrotreating used cooking oil, vegetable oil can only get you so far, because those resources are very constrained. There's not going to be more deep frying of food to produce more used cooking oil in response to a SAF policy — we're just kind of stuck with the market for used cooking oil that we have.”
Crops offer another route to producing SAF, but the amount of land that would be required is significant, with knock-on effects for warming and biodiversity as cropland is expanded into new areas.
If the U.S. were to reach a goal declared during the administration of former U.S. President Joe Biden of making 132.5 billion liters of SAF using ethanol, 46.13 million hectares of corn would be needed, according to the World Resources Institute — 20% more land than is currently used for all corn.
Such concerns are particularly acute for Japan’s own SAF production, given its limited amount of land suitable for cultivation.
In recognition of Japan’s limited land, “JAL is focusing on alternative feedstocks that are more suitable for Japan, such as forest residues, rather than traditional crops,” a spokesperson for the airline says. “JAL is actively exploring and investing in these alternative sources to mitigate the impact of land limitations and to support its sustainability goals.”
Alternatively, “efuels” made from hydrogen and captured carbon dioxide — which ANA is exploring in a project with Toshiba and others — don’t have the same concerns over the availability and sustainability of these biological feedstocks and boast low emissions. But even here the cost could be as much as nine times that of conventional jet fuel, according to BNEF.
Future of flying
For airlines, which aircraft you fly and how you fly it make a difference to a flight’s climate impact.
From parking to landing, tweaks at all stages of an aircraft’s journey can reduce emissions, for example through optimizing flight plans, adjusting the angle of flaps during takeoff or delaying the deployment of the landing gear. JAL sees such changes delivering a 5% emissions cut.
But the bigger prize is newer aircraft, first through more fuel-efficient models and later possibly from battery- or hydrogen-powered aircraft.
ANA expects to see operational changes and new aircraft contribute 20% of the emissions reductions needed to reach net zero, while JAL is relying on new aircraft for half of the necessary cuts, although it doesn’t break down the extent to which different kinds of planes will contribute to this. Newer aircraft can reduce emissions by between 15% and 25% compared with existing models, according to JAL.
Here, ANA is making much better progress than with its SAF rollout, with fuel-efficient aircraft making up 80.3% of the fleet in fiscal 2023, against a 90% target in fiscal 2030. For JAL, it was 86%, although the latest models only comprised 38% of the fleet.
“More efficient planes is actually one of the most underremarked, I would say less sexy strategies of reducing emissions than SAFs,” says Pavlenko. “It's necessarily a slower one, but they are genuine reductions.”
Looking further ahead, battery and hydrogen aircraft promise zero-emission flights, so long as the electricity or hydrogen powering them is produced with renewables or any carbon emissions are captured. They also offer a chance to eliminate or lower non-CO2 warming effects, which mostly come from contrails and chemical reactions driven by nitrous oxides.
In addition to industry titan Airbus, a number of startups are looking to develop aircraft based on these technologies. In 2023, JAL reached agreements with three of them to study the feasibility of hydrogen planes.
But major barriers stand in the way of their adoption, largely because of energy densities. For example, powering a narrow-body jet might require batteries weighing multiple times the aircraft’s designed takeoff weight.
Hydrogen, meanwhile, is light but takes up a lot of space compared with conventional fuels. That would displace the passengers and cargo that make flights economically viable. In addition, major investments would be required to get hydrogen to the world’s airports, and even then, carbon-neutral hydrogen remains in short supply.
Analysts say battery- and hydrogen-powered aircraft are very unlikely to replace jet fuel in long-haul flights — where the bulk of emissions come from — and at best will be limited to those over shorter distances, something JAL acknowledges.
“We recognize that aircraft powered by batteries and hydrogen will likely be limited to short- and medium-haul flights due to energy density issues, and our roadmap toward net-zero emissions is based on this concept,” the JAL spokesperson says.
Still, the outlook for hydrogen aircraft has become even cloudier in recent weeks.
On Feb. 7, Airbus scrapped a target to introduce hydrogen aircraft by 2035, without setting a new target, citing the use of the technology as a “huge challenge.” And just days earlier, a group of European aviation associations drastically scaled back their expectations for hydrogen, cutting its projected net-zero contribution to 6% from 20%.
“I think a 2050 goal that relies on large quantities of them (zero-emissions planes) is going to be largely unrealistic, and that's because these technologies have really meaningful barriers to their deployment,” says Pavlenko.
Absorbing the problem
If it’s tricky to cut down or remove CO2 emissions at the source, how about sucking the greenhouse gas out of the air and storing it somewhere where it can’t warm the planet?
Both airlines are looking to do just that by investing in and reaching agreements with “direct air capture” (DAC) startups in order to counteract emissions that will still remain even with SAF. ANA has a purchase agreement for carbon removal credits with 1PointFive, whose Texas plant is expected to go online this year, while late last year JAL joined a $150 million funding round for California-based Heirloom Carbon Technologies. Earlier in 2024, JAL invested in Captura, a company that is developing technology to extract CO2 from the ocean so that it can absorb more from the atmosphere.
Both airlines are looking to “negative emissions technologies” such as DAC to cover 10% of emissions, although in JAL’s case the use of emissions trading is encompassed by this too.
But again there are some big challenges. For one, DAC doesn’t account for non-CO2 warming effects, meaning possibly three to four times more CO2 would need to be captured than the aviation industry actually emits, while concerns have been raised about the economics and quality of storage sites. And because it is targeting low concentrations of CO2, DAC also requires phenomenal amounts of energy. That has a knock-on effect on price.
In a paper published in July last year, researchers from Ireland and Northern Ireland found that DAC could add €381 (¥61,000; $400) to an economy ticket on an intercontinental flight, although that may even seem cheap when compared with the €1,076 increase under a 100% efuel pathway.
“These potential additional costs may indicate that if the aviation sector is to continue in a net-zero future, the era of relatively low-cost flying is over,” the researchers wrote.
“You see a wide range of direct air capture costs, though that range is uniformly quite high,” says Pavlenko, “which suggests we're first not very certain about the cost of the technology, specifically suggesting it's quite far off, but also that it's quite expensive.”
Higher fares?
Given the costs suggested by current plans for aviation decarbonization, there is naturally a question of who is going to pay for it.
“Even some of the cheapest ... most commercialized SAF pathways on the market today essentially take something more expensive, vegetable oil, and turn it into something that has to compete against a very cheap product, fossil kerosene. The only way to make that at all appealing is either a subsidy or a mandate,” Pavlenko says.
For its part, ANA is “actively assessing future costs associated with decarbonization and closely monitoring the global increase in regulations,” a spokesperson for the airline says, adding that responsibility for advancing SAF production should be shared collectively in recognition of “the essential role of air travel in societal and economic development.”
JAL strikes a similar tone, saying, “To maintain and develop an aviation network that contributes to Japan's international competitiveness, we intend to study the approach to environmental cost-sharing across society while closely monitoring social trends and collaborating with relevant parties.”
Kawahara says that tax incentives have helped the U.S. take the lead on SAF. Unsurprisingly, airlines typically welcome anything that stops decarbonization costs from being reflected in ticket prices. That raises the question of shifts in demand, either as part of an explicit response to the costs and resource demands of net zero, or as a natural consumer response to price increases.
In response to questions, neither JAL nor ANA directly commented on the possibility of decreased passengers or flights, either as a result of specific government policy or as a consequence of reduced demand stemming from higher costs.
“Demand management is something that airlines are quite allergic to,” says Pavlenko. “And if you look at long-term plans from the airline industry, from agencies ... they forecast quite significant growth.”
Still, Kawahara points out that there are already signs ticket prices could go up in the long term — Lufthansa has already decided to introduce an environmental surcharge to help cover the cost of SAF and participating in the European Union’s carbon trading market. Meanwhile, ANA’s SAF Flight Initiative enables companies to invest in the fuel, with the resulting emission reductions counting against some types of CO2 emissions, such as those from business trips.
A key question is whether these decarbonization technologies can outpace the impact of the projected increase in demand. The Japan Aircraft Development Corp. predicts a 2-percentage-point gap between average annual growth in passenger kilometers and average annual emissions reductions from energy-efficient aircraft, SAF and efuel over the next 20 years.
In an analysis of global tourism emissions, of which aviation comprises just over half even before considering non-CO2 warming effects, researchers wrote in Nature Communications in December that demand thresholds will be needed to align tourism with the Paris Agreement’s temperature goals, as emissions savings from technology and efficiency improvements were strongly outweighed by emissions stemming from tourism expenditure growth.
They argued that the burden should fall most heavily on the top 20 highest-emitting tourism destinations (Japan ranked sixth), and advocated for the urgent consideration of CO2 taxes, carbon budgets and fuel mandates to rein in aviation emissions.
“Our findings provide concrete evidence that focusing alone on technology and efficiency gains is insufficient for achieving net-zero milestones. Strong measures to reduce travel demand are urgently required,” they wrote.
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