RFA pushes for GREET Model in SAF tax credit calculations

In a letter to Biden administration, the US ethanol industry recommended the interagency working group (IWG) to adopt the best “best available science and data” under the GREET model to estimate lifecycle greenhouse gas emissions of SAF from ethanol.

The Renewable Fuels Association (RFA) outlined detailed recommendations for updating the model used to estimate lifecycle greenhouse gas emissions of SAF.

This model, known as the “40B GREET,” will ultimately determine which fuels qualify for the lucrative tax credit.

The US Treasury Department released guidance in December to release an updated version of the GREET model by March 1 for use in estimating the lifecycle greenhouse gas emissions of SAF.

The RFA sees ethanol as a key player in the SAF revolution, citing its cost-competitiveness and existing production capacity of nearly 16bn gallons per year. However, ensuring its inclusion in the tax credit program hinges on accurately measuring its environmental impact.

“In order for the full potential of the IRA to be realized, it is imperative that the proper lifecycle analysis modelling framework be adopted by the Treasury and IRS,” the RFA stated in its letter.

The association’s recommendations noted that “it is important that the IWG clearly communicate to stakeholders that any indirect emissions estimates included in the final 40B GREET model are based on the results of predictive scenario analysis, not direct, empirical measurements.”

Meanwhile, it said the existing Argonne National Laboratory (ANL) GREET model array estimates potential emissions from land use change using the best available science and data.

However, it warned that alternative frameworks such as the Global Change Analysis Model (GCAM) have shortcomings that render them less suitable for estimating indirect emissions.

The association further said that in order to realise full potential of the Inflation Reduction Act (IRA), proper lifecycle analysis modelling framework be adopted by the Treasury and IRS.

The components of the ANL GREET modelling array meet standards, and once any significant indirect emissions from rice and livestock production have been incorporated, the resulting 40B GREET should be determined to satisfy the CAA section 211(o)(1)(H) criteria, it added.