Airlines push to reduce carbon footprint with greener fuels

Under pressure to reach net-zero greenhouse gas emissions by 2050, airlines are experimenting with so-called sustainable aviation fuels, or SAF. The most advanced contender is biofuel, mainly made from cooking oil, animal fats, agricultural crops and unused wood, though it is a struggle to use on more than a small fraction of flights because of the lack of supply and the high costs. In the coming decade, different types of alternative fuels could make flying even cleaner.

SAF are imitations of kerosene, the refined petroleum that has burned in jet engines for decades. Different types of SAF exist, but only biofuel is in use today. Biofuel reduces emissions by up to 80% versus conventional jet fuel. International standards allow carriers to burn up to 50% biofuel with kerosene, but a recent test from U.K. engine maker Rolls-Royce and energy company Royal Dutch Shell showed that 100% biofuel is safe.

SAF are in their infancy. From 2016 to 2020, roughly 300,000 out of around 188 million total flights world-wide used SAF—less than 0.2%, according to the International Air Transport Association.

Still, they are key to cutting aviation’s environmental footprint, industry experts say. Aviation has driven 3.5% of the world’s human-made greenhouse gas emissions, according to a September study by Manchester Metropolitan University. Air traffic, the second biggest source of transport emissions after roads, is expected to grow more than threefold by 2045 compared with 2015, though that doesn’t account for the pandemic-related stall in demand, according to the International Civil Aviation Organization.

United Airlines, which is aiming to get to net-zero emissions by 2050, first used biofuel in 2009 and started using it regularly in 2016. It used only 4 million gallons in the last five years, compared with the 4 billion gallons of conventional fuel the airline uses in an average year, says Lauren Riley, managing director of global environmental affairs and sustainability at United.

The airline doesn’t have much incentive to buy more: Biofuels cost up to four times more than conventional jet fuel, says Ms. Riley. “That’s where the business case falls apart," she says.

It is also not feasible to replace all kerosene jet fuel with biofuel because of the limited supply of biomass, says Andrew Murphy, aviation manager at the nonprofit Transport & Environment. Biomass comes from crops such as soybeans, solid waste such as leftover food, and unused timber such as wood pellets.

In the U.S., there are only around 340 million tons of biomass available, but biofuel would require several hundred million tons alone to power planes as demand for more jet fuel picks up in the coming decades, according to the U.S. Department of Energy. Other shipping and transportation companies are also competing for that supply.

Still, there is momentum for biofuel to help make aviation cleaner. Microsoft Corp. signed a deal late last year with Alaska Airlines and SkyNRG, a Netherlands-based maker of biofuel, to use it on some of its frequent business-travel routes. “We hope that others follow because if they don’t, we aren’t on track for our overall climate stabilization goals," says Lucas Joppa, chief environmental officer at Microsoft.

Shell, one of the world’s top suppliers of biofuel, took a 40% stake in a plant in Quebec, Canada, this year that will turn 200,000 metric tons of non-recyclable waste and wood waste a year into biofuel. Late last year, it signed deals with Amazon.com Inc. and DHL to provide SAF for their cargo planes.

Airlines say a solution to the pricing problem is government support, which looks more likely under a Biden administration. As part of his $2 trillion climate plan, President Biden pledged to “incentivize the creation of new, sustainable fuels for aircraft." The European Union is considering quotas for airlines to use SAF.

Another promising technology on the horizon is e-fuels. Also known as power-to-liquid fuels, they use renewable energy such as solar and wind to split water into hydrogen and oxygen, a process known as electrolysis. To make fuel, the hydrogen is then combined with carbon monoxide created from captured carbon dioxide. This fuel is seen as more promising to decarbonize the aviation industry because, in theory, it would offer an unlimited supply. It will likely still need years before it comes on the market.

“Scaling used cooking oil or scaling vegetable oils won’t be sustainable in the long run," says Annette Mann, head of corporate responsibility at Deutsche Lufthansa AG. “We really need the power-to-liquid technology which is now under development and still needs a lot of investment," she adds.

In early 2019, Lufthansa signed a letter of intent with Heide, a refinery near Hamburg, Germany, to make and purchase power-to-liquid jet fuel. The project will use wind energy from the North Sea. Within five years, the carrier expects to replace 5% of the kerosene it uses at its Hamburg hub with power-to-liquid fuel.

Anna Mascolo, president of global aviation at Shell, predicts costs for e-fuels to fall much like wind and solar as production scaled up, and that they can play a major role in the decarbonization of aviation from 2030 onward. “This one has the greatest potential," she says.

Massive government aid through taxes, incentives and subsidies is needed to bring down the costs of SAF and scale production, aviation experts say. These new fuels compete with much cheaper fossil fuels that have enjoyed $4.4 trillion in government subsidies over the past decade, according to the International Energy Agency.

Replacing all jet fuel with SAF is unlikely even by 2050, though halving the use of kerosene would bring airlines substantially closer to the goals to reduce greenhouse gas emissions outlined in the Paris climate agreement.

Other technologies such as hydrogen or electric aircraft are on the way, but far from mature yet.

“There is no competition between the pathways. You can’t say that the future is biofuel or the future is power-to-liquid or the future is hydrogen," says Nicolas Jeuland, environmental and low-carbon fuels prospective manager at French engine maker Safran SA. “We have to decarbonize now, we can’t afford to wait 10, 20, 30 years."

This story has been published from a wire agency feed without modifications to the text.