Clean Fuels Take on 40B SAF-GREET Release

The much-anticipated user interface to calculate the 40B SAF Blenders Tax Credit using Argonne’s GREET model was released on April 30. The good news is that all the Clean Fuels’ HEFA feedstocks should qualify under the tax credit in some capacity. Using the GREET methodology, all feedstocks except canola will qualify, while canola can meet the 50% reduction threshold for the 40B tax credit by employing the RFS safe harbor. 

When it comes to the final methodology employed in 40B SAF-GREET, we see the addition of 2 indirect emission source category penalties beyond ILUC. In order to comply with the RFS’s definition of life cycle emissions, GREET’s indirect emissions penalty includes both non-feedstock crop production and livestock emissions associated with changes in crop production and increased supplies of meal induced from increased supplies of the feedstock crop for SAF production. Importantly, these additional emission sources are housed in the user interface for 40B rather than GREET itself. In addition, these penalties are variable based on fuel producer inputs that reflect more or less efficient conversion of feedstock to fuel, so better conversion rates will show lower penalties for individual facility CI calculations.

The user interface also allows for CI reductions from the use of green hydrogen, landfill renewable natural gas and renewable electricity. 

Lastly, soy oil produced from acres grown with no till and cover crops can get a 5g CO2e/MJ reduction in CI associated with the oil to promote climate smart agriculture practices. This nearly 57% reduction in the CI of soy is precedent setting. No CI program to date has differentiated between agricultural feedstocks employing different land management practices.

More details on the methodology used in 40 BSAF-GREET is available at, with information on how to qualify for lower CI fuel production and feedstock production available at under 40BSAF-GREET’s user manual and

Originally shared by Clean Fuels Alliance America and written by Veronica Bradley. Title updated for purpose.

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