One Fuel, Many Filters: Navigating Global Differences in SAF Sustainability Rules
Rahul Jain, Biofuels Specialist, Global Biofuels Alliance 
15th
September 2025
Rahul Jain, Biofuels Specialist, Global Biofuels Alliance 15th
September 2025
Sustainability is defined as something that can be continually and repeatedly resourced in a manner consistent with economic, social and environmental aims, and conserves an ecological balance by avoiding depletion of natural resources1 .. While airlines can utilize any SAF that meets technical certification standards, such as ASTM D7566, these certifications only verify the physical properties of the fuel and do not inherently ensure sustainability. The key factor in determining SAF’s sustainability is its ability to reduce net carbon emissions, which is assessed through life cycle analysis. For SAF to contribute meaningfully to the aviation sector’s climate targets, it must demonstrate a net reduction in carbon emissions compared to conventional fossil-based jet fuels.
At present, sustainability criteria for SAF vary significantly across different regions. For example, under the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA), sustainability criteria are categorized into three main pillars: Carbon Reduction, Environmental Impact, and Socio-Economic Considerations. CORSIA mandates that SAF must achieve at least a 10% reduction in net greenhouse gas (GHG) emissions relative to the baseline life cycle emissions of conventional aviation fuel, which is set at 89 gCO2 e/MJ2 .
In Europe, the ReFuelEU Aviation Regulation mandates a progressive increase in SAF supply, beginning with 2% in 2025, rising to 6% by 2030, and eventually reaching 70% by 20503 . The regulation requires all SAF to comply with the sustainability and GHG reduction benchmarks outlined in the Renewable Energy Directive (RED). Under the RED II framework, life cycle GHG emissions from SAF must be lower than the fossil fuel baseline of 94 gCO2e/MJ4 . The required reductions are at least 50% for facilities operating before October 5, 2015, 60% for those starting after that date, and 65% for installations beginning production post-2021. Furthermore, renewable fuels from non-biological sources and recycled carbon fuels must achieve at least a 70% reduction5 .
The UK has introduced a SAF Mandate as a key policy instrument to ensure long-term SAF demand and promote GHG emissions reduction in aviation. This mandate legally obligates fuel suppliers to incorporate an increasing share of SAF, starting at 2% of total fossil jet fuel supply in 2025 (around 230,000 tonnes of SAF), increasing to 10% in 2030 and 22% by 20406 . UK sustainability criteria dictate that SAF must achieve at least a 40% GHG reduction compared to the fossil fuel benchmark of 89 gCO2e/MJ7 .
In the United States, an aspirational goal of 3 billion gallons of SAF by 2030 and 35 billion gallons of SAF to satisfy 100% of domestic demand by 2050 was established under the SAF Grand Challenge. The challenge also requires a minimum of a 50% reduction in life cycle emissions compared to conventional fuel8 . Similarly, Renewable Fuel Standard (RFS) program establishes life-cycle emissions reduction thresholds for various renewable fuel categories. For advanced biofuels, the required reduction is 50% compared to the 2005 petroleum baseline9 . Under the U.S. Inflation Reduction Act, tax incentives under Sections 40B and 45Z require SAF to achieve at least a 50% reduction in lifecycle emissions compared to conventional jet fuel in order to qualify for credits.. Additionally, several U.S. states have independent SAF-related initiatives. Programs such as California’s Low Carbon Fuel Standard, Oregon’s Clean Fuels Program, and Washington’s Clean Fuels Standard classify SAF as an "opt-in" fuel, allowing it to generate credits within these regulatory frameworks.
India, Japan, and Singapore emphasize adoption mandates without clearly specifying life-cycle emission reduction thresholds. India targets 1% SAF blending in international flights by 2027, increasing to 2% in 2028, without publicly detailing LCA criteria10 . Japan is working toward a 10% SAF mandate by 2030, backed by subsidies, though specific emission reduction requirements remain unspecified11 . Singapore plans to introduce 1% SAF use from 2026, scaling up to 3–5% by 2030 through funding from a passenger levy12 , but has not outlined explicit LCA reduction targets.
The disparity in sustainability criteria across regions creates inconsistencies in SAF certification. A fuel that qualifies as SAF with relatively lower GHG reduction thresholds in one region may face stricter requirements elsewhere, placing production projects at a competitive disadvantage in certain markets
Inconsistent rules act as trade barriers, limiting global market access and leading to inefficiencies in scaling production. Producers may be forced to “fuel shuffle,” directing SAF to markets with the most favourable rules rather than those with the greatest decarbonization needs. Investors and airlines face uncertainty, making it harder to commit to long-term offtake agreements. This uneven playing field can create competitive imbalances, slow infrastructure investment, and ultimately delay aviation’s net-zero ambitions.
Addressing these challenges calls for coordinated international action. A first step would be creating interoperability among life-cycle assessment methodologies, using a globally accepted framework. Mutual recognition agreements between countries could streamline market access by accepting SAF verified under equivalent sustainability schemes. Establishing standardized feedstock lists and a centralized SAF registry- encompassing feedstock suppliers, SAF producers, and off-takers would enhance transparency and facilitate cross-border trade. Capacity-building support for emerging markets, coupled with active public–private collaboration, could help ensure that SAF certification systems are robust, aligned, and inclusive. While SAF is widely recognized as one of the most promising solutions to decarbonize aviation, its full potential can only be realized if the global community works toward aligning sustainability criteria.