As the clock continues to tick, the Sustainable Aviation Fuel Interagency Working Group continues its work on a modified GREET model for the 40B SAF tax credit.

The Renewable Fuels Association this week provided some input to the working group regarding what time period should be used for land use change (LUC) emissions accounting under the new model. In a letter to the agency heads, RFA President and CEO Geoff Cooper explained why the time period should be 30 years.

EPA’s 2010 RFS lifecycle GHG analysis (and subsequent EPA rulemakings) used a 30-year timeframe to account for LUC emissions. Treasury has already determined that EPA’s 2010 RFS lifecycle analysis methodology, which integrates a 30-year time profile for LUC emissions accounting, satisfies the criteria of 211(o)(1)(H). Thus, using anything other than a 30-year period (e.g., 20 or 25 years) for the upcoming 40B(e)(2) GREET model would likely render the new model inconsistent with the requirements of CAA 211(o)(1)(H), as interpreted and implemented by EPA.

The working group – which consists of USDA, EPA, Energy, and Treasury – had set a March 1 deadline to announce the modified model, but has yet to give any indication when it may happen at this point. The clock is ticking because the 40B applies to fuel used or sold after 2022 and before 2025, or by the end of this year. The tax credits were included in the Inflation Reduction Act passed by Congress in 2022.