^a  40B calculator includes iLUC results from GREET plus other iLUC categories including methane from livestock and rice.

While these frameworks provide structure and support for the aviation industry to maximize these GHG reduction potentials, the wide range of analysis requirements inherently lead to inconsistent reporting of SAF emissions. Globally, aviation contributes 2% of all carbon dioxide (CO2) emissions and 12% of CO2 emissions within the transportation sector. Using 100% SAF could reduce GHG emissions by up to 94%, depending on the feedstock and technology pathway. Ensuring interoperability across these various frameworks will be a leading factor for achieving the GHG emission reduction potential for the aviation sector.

LCA Certification Tools/Methods

LCA certifications and tools are essential for comprehensively evaluating the environmental impacts of products and processes throughout their entire life cycle on a WTW basis. By adhering to standardized methodologies, such as those set by the International Standards Organization (ISO), these certifications ensure consistency, reliability, and credibility in the assessment results.

CORSIA

CORSIA is an ICAO (International Civil Aviation Organization) initiative with the goal to achieve carbon-neutral growth from a 2020 baseline through the adoption of credits or CORSIA eligible fuels (CEF). A CEF must meet certain sustainability requirements, which includes a CI reduction of at least 10% relative to a conventional jet fuel baseline. SAF is a drop-in replacement fuel for conventional jet fuel within the CEF category, made from feedstocks including oils and fats, biomass, municipal solid waste, other waste resources, and even renewable power and waste CO2.

For SAF to qualify under CORSIA, an LCA can be conducted with the International Sustainability and Carbon Certification (ISCC) CORSIA methodology or with a specialized calculator developed by the Roundtable on Sustainable Biomaterials (RSB). Upstream life cycle data may be drawn from one of the approved sources including the GREET model. Under CORSIA, indirect land use conversion (iLUC) values are derived from the Global Trade Analysis Project (GTAP) and Global Biosphere Management Mode (GLOBIOM) models. The CORSIA LCA methodology is also used under the IRA.

CA LCFS Tier 1 Calculator

California’s LCFS program sets GHG reduction targets on transportation fuels that are expected to be met through the substitution of lower CI renewable fuels for higher CI conventional fuels and by technology substitution. Currently, LCA analysis is performed using CA-GREET3.0 and CARB’s Tier 1 Calculators. The LCI data in CA-GREET3.0 and the Tier 1 Calculators are derived from GREET1_2016 with LUC values developed by CARB in 2015 based on the GTAP model.

EU RED

The EU implemented the Renewable Energy Directive (RED) to promote and support the adoption of renewable energy sources. This set of regulations utilizes different strategies, such as free attribution, mass balance, and book and claim credits, to monitor and incentivize the use of renewable biofuels. Similar LCA tools and the RSB tool used for CORSIA compliance is also similar to EU RED. EU RED does not include iLUC emissions as feedstocks with high risk of creating significant GHG emissions due to land use change are not allowed under the program.

IRA – 40BSAF calculator

The IRA 40BSAF-GREET 2024 is based on the Greenhouse gases, Regulated Emissions, and Energy use in Technologies (R&D GREET) model developed and maintained by Argonne National Laboratory. The SAF specific calculator is used to evaluate the emissions reduction percentage of feedstock-specific SAF production pathways. Through 2024, SAF is eligible for a standalone blender’s credit under Section 40B, provided the fuel achieves at least a 50 percent reduction in GHG emissions. The value of the credit is calculated on a sliding scale, starting at $1.25 per gallon, and adds $0.01 for each percentage point below 50 percent. From 2025 to 2027, SAF incentives will be incorporated into Section 45Z, which is expected to have its own unique GREET calculator.

Conclusions

U.S. SAF production hit a record of nearly 275 million gallons per year in 2023, with 50% growth forecasted in 2024 and year over year growth forecasted to double in 2025. While production reached a record, penetration into the fuel supply remains low, well below 1%. The consistent implementation and interoperability between the range of policies, incentives, and GHG frameworks will support global uptake of the market, especially as targets and mandates reach their deadlines. Unlocking more commercially competitive SAF pathways, in compliance with the respective LCA framework will bolster further adoption allowing the industry to fully takeoff.