SECTION 1. PURPOSE

The Department of the Treasury (Treasury Department) and the Internal Revenue Service (IRS) provided initial guidance on December 19, 2022, regarding the sustainable aviation fuel (SAF) credits in Notice 2023-6, 2023-2 I.R.B. 328. Such credits are collectively referred to as a “SAF credit” or the “SAF credits.” This notice provides additional guidance with respect to the SAF credits under §§ 40B and 6426(k) of the Internal Revenue Code. ¹

Section 2 of this notice provides relevant background and an overview. Section 3 of this notice provides safe harbors for calculating the lifecycle greenhouse gas

emissions reduction percentage under § 40B(e)(2) and for certifying the related requirements under § 40B(f)(2)(A) (sustainability requirements). Section 4 of this notice describes Appendix A of this notice, which contains a Model Certificate for SAF Synthetic Blending Component and supersedes Appendix B of Notice 2023-6. A certificate is required under section 6.04(2) of Notice 2023-6 in order to make a claim with respect to a SAF qualified mixture under § 34(a)(3), 40B, 6426(k), or 6427(e)(1). Section 5 of this notice explains that the existing Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET) model of the Argonne National Laboratory (ANL-GREET model) ² is a methodology that does not satisfy the requirements to calculate the emissions reduction percentage under § 40B(e)(2). To date, no GREET-based model has been identified as satisfying the applicable requirements. ³

Finally, section 6 of this notice announces that the Department of Energy (DOE) is collaborating with other federal agencies to develop a modified version of the GREET model that would satisfy the requirements of § 40B(e)(2) (§ 40B(e)(2) GREET model). The agencies developing the § 40B(e)(2) GREET model currently anticipate it to be released in early 2024.