SECTION 5. ANL-GREET

There are different methodologies that may be used to calculate lifecycle greenhouse gas emissions, such as those established by CORSIA and RFS. A widely used model for calculating an emissions reduction percentage is the GREET model. There are several existing GREETbased models such as CA-GREET used by the California Air Resources Board for the California Low Carbon Fuel Standard, and ICAO-GREET used by CORSIA, ⁶ but the core version is the ANLGREET model developed by Argonne National Laboratory, with DOE support, in 1994. The ANL-GREET model is updated annually and produces a lifecycle greenhouse gas emissions value that is comparable to the lifecycle greenhouse gas emissions of petroleum-based fuels, including jet fuel.

Section 40B(e)(2) allows the emissions reduction percentage to be determined in accordance with a methodology that is “similar” to CORSIA and satisfies the CAA § 211(o)(1)(H) criteria. The EPA has previously determined, in the context of the RFS program in which it has interpreted and implemented § 211(o)(1)(H) of the CAA, that the 2010 version of the ANL

GREET model by itself is not sufficient to calculate lifecycle greenhouse gas emissions. The EPA has further advised that, as relevant to § 40B(e)(2), the only current methodology that it has determined satisfies the CAA § 211(o)(1)(H) criteria is the methodology, modeling, and analysis the EPA developed in 2010 for the RFS program and applied in subsequent RFS rulemakings. ⁷ Based on those consultations, the Treasury Department and the IRS conclude that the ANL-GREET model and other existing GREET-based models do not satisfy the applicable requirements.

SECTION 6. § 40B(e)(2) GREET MODEL

The DOE is collaborating with other federal agencies to develop the §40B(e) (2) GREET model to calculate the emissions reduction percentage under § 40B(e) (2). The collaborating agencies anticipate that the § 40B(e)(2) GREET model will be available in early 2024, and will satisfy the statutory requirements of § 40B(e)(2). After the § 40B(e)(2) GREET model is released, and subject to any further guidance from the Treasury Department and the IRS, it is anticipated that taxpayers will be able to use the § 40B(e)(2) GREET model to calculate the emissions reduction percentage for SAF sold or used after December 31, 2022, and prior to January 1, 2025. A registration applicant using the § 40B(e)(2) GREET model would also need to meet all statutory requirements under § 40B, including registration, sustainability, traceability, and unrelated party certification.