If Treasury uses GREET to model SAF lifecycle greenhouse gas emissions, it must modify it to be both similar to CORSIA and to fully account for indirect land use changes

The Clean Air Task Force asserts that the 40BSAF-GREET model used by the US Treasury fails to meet statutory requirements for section 45Z because its indirect land use change (ILUC) values are significantly lower than those in the CORSIA and EPA RFS frameworks. The author calls for updated ILUC numbers to comply with the Clean Air Act.

• The 40BSAF-GREET model is not 'similar' to the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) because it relies only on the GTAP-BIO model for indirect emissions, whereas CORSIA uses both GTAP-BIO and GLOBIOM. Additionally, 40BSAF-GREET amortizes indirect emissions over 30 years compared to CORSIA's 25-year period, which results in indirect emissions being 16.7% lower.
• ILUC values in 40BSAF-GREET for corn (11.1 g CO2e/MJ) and soy (16.2 g CO2e/MJ) are 37-55% lower than the CORSIA defaults of 25.1 g CO2e/MJ for corn and 24.5 g CO2e/MJ for soy.
• The 40BSAF-GREET model does not properly account for indirect land use change under Clean Air Act (CAA) section 211(o)(1)(H). Its indirect emission values for corn and soy are 52-60% lower than the values used by the EPA in the Renewable Fuel Standard (RFS) program, which are 27.8 g CO2e/MJ for corn and 33.6 g CO2e/MJ for soy.

APA

Firth, S. (2024). If Treasury uses GREET to model SAF lifecycle greenhouse gas emissions, it must modify it to be both similar to CORSIA and to fully account for indirect land use changes. Clean Air Task Force. https://www.catf.us/2024/08/if-treasury-uses-greet-to-model-saf-lifecycle-greenhouse-gas-emissions-it-must-modify-it-to-be-both-similar-to-corsia-and-to-fully-account-for-indirect-land-use-changes/

Chicago

Firth, Sammie. If Treasury uses GREET to model SAF lifecycle greenhouse gas emissions, it must modify it to be both similar to CORSIA and to fully account for indirect land use changes. Clean Air Task Force, 2024. https://www.catf.us/2024/08/if-treasury-uses-greet-to-model-saf-lifecycle-greenhouse-gas-emissions-it-must-modify-it-to-be-both-similar-to-corsia-and-to-fully-account-for-indirect-land-use-changes/.

Wikipedia

{{cite press release |last1=Firth |first1=Sammie |title=If Treasury uses GREET to model SAF lifecycle greenhouse gas emissions, it must modify it to be both similar to CORSIA and to fully account for indirect land use changes |publisher=Clean Air Task Force |date=19 August 2024 |url=https://www.catf.us/2024/08/if-treasury-uses-greet-to-model-saf-lifecycle-greenhouse-gas-emissions-it-must-modify-it-to-be-both-similar-to-corsia-and-to-fully-account-for-indirect-land-use-changes/ |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@misc{firth2024treasury, author = {Firth, Sammie}, title = {{If Treasury uses GREET to model SAF lifecycle greenhouse gas emissions, it must modify it to be both similar to CORSIA and to fully account for indirect land use changes}}, publisher = {Clean Air Task Force}, year = {2024}, month = aug, url = {https://www.catf.us/2024/08/if-treasury-uses-greet-to-model-saf-lifecycle-greenhouse-gas-emissions-it-must-modify-it-to-be-both-similar-to-corsia-and-to-fully-account-for-indirect-land-use-changes/}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }