Decarbonizing aviation will only be possible with policies in support of biofuels
Jack Saddler, co-author of an IEA Bioenergy study on the aviation sector, advocates for bio-based fuels as the most plausible path to net zero by 2050; governments will play a crucial role in reaching agreed targets; the professor is one of the panelists discussing biofuel advancements in transportation on October 23 at the BBEST – IEA Bioenergy Conference.
For the world to meet the total decarbonization targets for the aviation sector by 2050, governments—and society at large—will have to take part of the bill, and it won’t be cheap. At current prices, sustainable aviation fuels (SAFs) which predominantly refer to biojet fuel, cost about two to five times more than its fossil fuel equivalent. Therefore, governments will play an important role as policies will become increasingly important in the aviation sector’s race to net zero.
This is a summary of the analysis by Jack N. Saddler, former leader of IEA Bioenergy Task 39 on liquid biofuels. Saddler is also a professor of Bioenergy and Biofuels at the University of British Columbia in Vancouver, Canada and together with Susan van Dyk, he co-authored the latest IEA Bioenergy report on sustainable aviation fuels (SAF) which was published in January of this year.
Saddler is visiting Brazil to participate in the BBEST – IEA Bioenergy Conference on October 23 in São Paulo, where he will join a panel discussing the ongoing progress in adopting biofuels in transportation. The report he co-authored emphasizes that nearly 2-3% of global carbon equivalent emissions come from the aviation sector, which accounts for around 915 million tons of CO2e annually. Although neutralizing this volume of greenhouse gas emissions will not be easy, part of the answer lies in bio-based fuels—such as fuels derived from used cooking oil (UCO).
The IEA Bioenergy report highlights the importance of renewable aviation fuels, typically known by the acronym SAF. One should also note the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA), a program by the International Civil Aviation Organization (ICAO), which set decarbonization goals for civil aviation by 2030, along with measurement criteria and other milestones.
According to Saddler, there are several ways to decarbonize aviation, including airplane design, engine efficiencies, improvements in ground transportation, air traffic control systems, etc. However, the use of SAF will have the biggest impact. The International Air Transport Association (IATA) believes that SAF has the potential to decrease up to 65% of aviation’s greenhouse gas emissions (GHG)—a significant number. “We simply do not have viable alternatives to decarbonize the aviation sector at a larger scale,” explains Saddler. “Although green electricity and green hydrogen technologies exist, technically and economically, they will be limited in their uptake. In both cases, their use for long-distance flights (e.g., trans-oceanic) is very unlikely”.
Green electricity, which requires substantial on-board battery capacity, could potentially apply to short-distance flights. The use of hydrogen has several challenges. For long flight, almost two-thirds of the aircraft would need to be reserved for hydrogen fuel storage, plus keeping it in liquid form at extremely low temperature. “On the other hand, it is possible to fly today, with the technology we already have, on an aircraft using biojet fuel from Brazil to Europe,” Saddler points out.
However, the challenge lies in the volume of biojet fuels needed to decarbonize the global aviation sector. A report by Aviation Consulting and Services (ICF), prepared for ATAG Waypoint 2050, and cited in the IEA Bioenergy study, estimates an annual need for 412 billion to 556 billion liters of SAF. The IATA Infrastructure Net Zero Roadmap forecasts a demand for 400 million tons of SAF annually by 2050. IATA estimates that this year’s SAF production will not exceed 1.9 billion liters (1.5 million tons), or just 0.53% of aviation’s fuel needs in 2024.
The IEA Bioenergy Task 39 study discusses several technologies. Of the feedstocks that can be converted into SAF, Saddler highlights the use of used cooking oil (UCO). “Ten years ago, collecting used cooking oil was a challenge as it was a low-value waste,” he explains. But since its carbon footprint is low, it is an excellent option for transport fuels and demand for UCOs has increased. “In some cases, UCOs have become more expensive than virgin oils”. This same low-carbon-lipid-feedstock can be used to produce biojet fuel, but also to make biodiesel or renewable diesel (also called HVO in Europe). Saddler points out that this ongoing competition between SAFs and bio/renewable diesel should be attractive to waste collectors and also agricultural producers as it increased the demand for their lipid products. “However, there is significant pressure on farmland for feedstocks such as palm oil, canola, soya, etc., and this is why it will be very difficult for governments to implement 100% SAF policies in the short term”. In the medium-term other biofuel production technologies will need to come to market that are capable of using a much broader spectrum of biomass feedstocks.
Notwithstanding, in the last few years Saddler has seen significant progress as some airlines are already flying with 5% biofuel blends while others have shown that even 100% SAF can be used. He adds that, due to certain state policies, many countries have already committed to adopting a 10% SAF blend by 2030.
The good news is that SAF production and use is expected to expand. A survey by Argus Media, cited in the IEA Bioenergy report, mapped 142 plants announced worldwide with a combined capacity to produce 33 billion liters per year. Despite this excellent progress, Saddler, still considers the net-zero target for 2050 to be highly ambitious given the current landscape. “The 2030 target of a 10% SAF blend is rapidly approaching. I believe it’s achievable if governments are committed to implementing public policies favorable to biojet fuels”.