Global aviation's shift towards sustainable aviation fuel (SAF) remains in its infancy, with the fuel constituting a mere 0.3% of worldwide jet fuel output in 2024, according to the International Air Transport Association (IATA). This slow uptake occurs despite aviation contributing approximately 2.5% of all energy-related emissions, a share projected to grow as other transport sectors electrify. Industry leaders are now openly questioning the feasibility of upcoming mandates.
The International Air Transport Association (IATA) described the low adoption rate as "disappointing." The industry body estimates a modest increase to 0.7% in 2025. This incremental progress falls short of the sector's stated net-zero ambitions for 2050. The core issue, as always, is economics.
Here is the number that matters: SAF currently costs between two and seven times more than traditional jet fuel. This significant price differential stems primarily from the limited availability of suitable raw materials, known as feedstocks, and the challenges involved in scaling up production to achieve cost efficiencies. Compounding this, fossil fuel-based jet fuel benefits from wide-ranging tax exemptions, which artificially depress its market price.
Most SAF today relies on a process called Hydroprocessed Esters and Fatty Acids (HEFA). This technique extracts oxygen from natural oils and fats, replacing it with hydrogen. Used cooking oil (UCO) serves as the most common feedstock for HEFA-based SAF, particularly in Europe.
Policies there favor UCO as a recycled waste product, which avoids competition with food production and reduces deforestation risks associated with virgin oils like soy or palm. Other nations prioritize locally sourced feedstocks. The United States, for instance, often looks to soy.
Brazil, another agricultural powerhouse, leverages palm oil. Both countries also anticipate producing substantial quantities of SAF by converting ethanol derived from corn or sugarcane. This method yields another type of drop-in fuel, known as alcohol-to-jet.
Beyond organic waste and crops, synthetic fuels offer another pathway. These, known as e-SAF or power-to-liquid SAF, are manufactured from green hydrogen—produced using renewable electricity—and carbon dioxide captured from the atmosphere or industrial processes. E-SAF can reduce emissions by up to 90% compared to conventional jet fuels.
However, its manufacturing cost remains exceptionally high, limiting widespread adoption. Some governments are attempting to expand the market for cleaner aviation fuels through a combination of financial incentives and compulsory usage requirements. The European Union and the United Kingdom implemented the world's first SAF mandates in January 2025.
These regulations compel fuel suppliers to blend at least 2% SAF with conventional kerosene. This blending requirement will not remain static. It is scheduled to increase progressively, reaching 32% in the European Union and 22% in the United Kingdom by 2040.
Similar SAF mandates are poised to take effect over the next few years in Singapore and Brazil. Major aviation hubs such as Japan and China also plan to introduce their own targets, indicating a global push. In contrast to mandates, the United States has chosen a different path.
Rather than imposing blending requirements, Washington has opted for direct subsidies and tax credits. This strategy aims to stimulate SAF production by making it more financially attractive for manufacturers, hoping supply will meet demand over time. Despite these policy efforts, projections suggest a significant shortfall.
The International Energy Agency (IEA) estimates that existing and advanced-stage SAF projects will fulfill just 2% to 4% of global jet fuel demand by 2030. This figure falls far short of the volume needed to align the sector with its declared goal of achieving net-zero emissions by 2050. The market is telling you something.
Listen. Airlines have repeatedly voiced their concerns regarding the scarcity of SAF supplies. They are pushing for policies that specifically incentivize increased production.
In March, the chief executives of Ryanair, International Airline Group (IAG), Lufthansa, and Air France-KLM collectively stated that the European Union's 6% SAF requirement for 2030 would be impossible to meet. They cited both the high cost and the limited availability of the fuel. Luis Gallego, CEO of IAG, which owns British Airways and Iberia, urged the EU for an urgent aviation strategy to secure SAF at competitive prices, Reuters reported.
Without such a strategy, he suggested, “the only realistic solution is to move the 2030 SAF mandate to the right.” The European Union responded by asserting its SAF targets were “realistic and feasible.” Airlines and fuel producers continue to advocate for greater government financial support to expand e-SAF production and reduce its cost. Ensuring the environmental integrity of SAF is another complex layer. Governments and the International Civil Aviation Organization (ICAO) require certification to verify the sustainability of each SAF batch and its raw materials.
The International Sustainability and Carbon Certification (ISCC) system leads this effort, issuing certificates used by EU regulators to confirm the origin and sustainability of SAF produced and used within the bloc. Approved third-party auditors inspect SAF producers and raw material traders globally. If they meet standards for feedstock origins and carbon savings, they receive ISCC approval.
However, guaranteeing the sustainability of feedstocks across intricate supply chains presents significant challenges. Fraud is a problem. For used cooking oil, for instance, suppliers at the point of origin, such as restaurants and individuals, must complete a self-declaration form.
The entire system relies on their honest declaration that the product is genuinely waste oil, used repeatedly and no longer suitable for cooking. This reliance has drawn criticism. In 2024, the ISCC conducted 79 “integrity assessments,” with approximately two-thirds targeting Asia-based suppliers.
A third of the analyzed cases revealed violations of certification requirements, leading to the withdrawal of 11 certificates. This is a vivid concrete detail that reveals the character of the challenge. With airlines paying a substantial premium to incorporate SAF into their airport fuel supplies, some have begun passing these additional expenses onto passengers.
Air France-KLM and Lufthansa have introduced mandatory SAF levies on tickets. The German flag carrier charges up to 72 euros ($82) per flight, depending on the route and fare class. This directly affects consumer pockets.
Singapore, aiming to become a regional SAF hub, will impose a SAF levy on travelers departing from the country starting in 2026. All departing flights will be required to carry 1% SAF. Preliminary estimates from the Civil Aviation Authority of Singapore suggest economy-class passengers might incur an extra S$3 ($2.30) levy for short-haul flights and S$16 ($12.40) for long-haul flights.
A growing number of airlines also offer customers the option to pay a voluntary SAF charge to offset their journey's carbon footprint. British Airways encourages loyalty program members to make voluntary contributions, allowing them to use and earn points. Low-cost Spanish airline Vueling, also owned by IAG, offers passengers the chance to contribute an amount equivalent to 2% of their total fuel cost, a contribution Vueling matches.
Strip away the noise, and the story is simpler than it looks: aviation faces a unique decarbonization challenge. Unlike road transport, which sees clear pathways to electrification, commercial aircraft still lack viable electric alternatives. This makes SAF the primary near-term solution, yet its high cost and limited supply, coupled with complex sustainability verification, create a difficult policy landscape.
For developing nations, the competition for feedstock resources also presents a dilemma between energy transition and food security or land use. The global south perspective often highlights these trade-offs, which are less apparent in Western policy discussions. - SAF constitutes only 0.3% of global jet fuel, far short of climate goals. - High costs, 2-7 times traditional fuel, and limited feedstock availability hinder widespread adoption. - Mandates in EU/UK face airline skepticism over feasibility, while the US prefers subsidies. - Sustainability certification systems struggle with fraud, particularly in UCO supply chains. Going forward, observers will watch for how governments reconcile ambitious mandates with the economic realities of SAF production.
The effectiveness of US subsidies in stimulating supply, compared to European mandates, will provide valuable data. Further technological breakthroughs in e-SAF production, capable of significantly lowering costs, remain a critical long-term factor. Consumers should anticipate continued SAF levies on tickets as airlines navigate these transition costs.
Key Takeaways
— - SAF constitutes only 0.3% of global jet fuel, far short of climate goals.
— - High costs, 2-7 times traditional fuel, and limited feedstock availability hinder widespread adoption.
— - Mandates in EU/UK face airline skepticism over feasibility, while the US prefers subsidies.
— - Sustainability certification systems struggle with fraud, particularly in UCO supply chains.
Source: Climate Home News