The GREET model is the only lifecycle analysis model that accurately captures all of the emissions reductions and accounts for environmentally-friendly innovations on farms and in bioethanol plants across the U.S.


The GREET Model uses the most up-to-date science to accurately estimate the emissions reductions of bioethanol.

The U.S. Department of Energy Argonne National Lab’s Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) Model is the gold standard for measuring the emissions-reducing power of farm-based feedstocks and biofuels. It incorporates up-to-date science that more accurately scores lifecycle carbon intensity for corn ethanol and other renewable fuels.

If federal regulators use the GREET model to administer tax credits from the Inflation Reduction Act, it is more likely that national goals such as the Biden Administration’s SAF Grand Challenge for decarbonization of the airline fleet will be met. Additionally, farmers, rural communities, and U.S. biofuel producers will be able to participate in global SAF markets and seize opportunities in other hard to decarbonize sectors.

The GREET Model, According to the Experts

The data used by the GREET model to calculate overall lifecycle emissions is kept up-to-date by a team of scientists and researchers at the Argonne National Lab. Paul Kearns, the director of Argonne National Lab, notes in this video that GREET is the “gold standard” when it comes to carbon modeling and is used by thousands of different authorities and organizations across the globe.

Two graphs show the difference in how CORSIA and GREET account for the carbon intensity-reduction potential of using U.S.-made corn ethanol to produce sustainable aviation fuel (SAF).

If the Administration rejects GREET, or changes it substantially, it would undermine our carbon reduction goals, and lock America’s farms out of the still-nascent SAF market.

Why GREET Is a Better Model than CORSIA

CORSIA stands for Carbon Offsetting and Reduction Scheme for International Aviation. It’s built and maintained by the International Civil Aviation Organization (ICAO) and the CORSIA model is simply referred to as ICAO. CORSIA relies on some of the same data used by GREET to arrive at its estimates of carbon intensity, but in other important areas the two models diverge.

The most noteworthy and important of these differences comes down to how each model accounts for land-use change (LUC or sometimes indirect land use change or iLUC). GREET’s estimate of how much the production of bioethanol impacts land use is based on much more recent data than CORSIA’s; farmers that produce the corn that goes on to make bioethanol have found ways over the last several decades to increase their crop yield on fewer acres while decreasing how much their planting processes disturb the soil. GREET accounts for these innovations, while CORSIA uses a land-use change estimate that’s based on data from nearly a decade ago.

CORSIA’s estimate of bioethanol’s carbon intensity is much higher than GREET’s because it inflates how much the process of making bioethanol disturbs the land. If regulators awarding carbon reduction tax incentives were to only rely on CORSIA, they would disqualify most bioethanol produced from corn and thereby lock these farms and producers out of the SAF market.

There's More to Learn

Read more about the importance of GREET and carbon reduction tax incentives.