Understanding Carbon Intensity Scores: A Guide for Farmers

As the biofuel industry grows, the importance of carbon intensity (CI) scores in assessing the environmental impact of fuels, particularly ethanol, becomes increasingly significant. This is important for the ethanol industry to continue to showcase how ethanol is an environmentally friendly solution to climate change.

Specifically, there is a lot of interest surrounding the Inflation Reduction Act and potential programs resulting from included tax incentives. The theory is that a biofuel producer would get a tax incentive to lower the carbon emissions associated with producing that fuel and pass that along to the feedstock producer (i.e., corn farmer). While we wait for guidance on how this will be rolled out into the countryside it is important for producers to do some research to know first what a carbon intensity score is and second how to calculate the intensity score of their corn fields.

For farmers, understanding CI scores and the models used to calculate them offers opportunities to enhance sustainability practices and potentially improve profitability. This article provides an overview of CI scores, their calculation methods, and specific models such as those developed by the California Air Resources Board (CARB) and the Greenhouse gases, Regulated Emissions, and Energy use in Technologies (GREET) model.

What are Carbon Intensity Scores?

Carbon intensity scores measure the total greenhouse gas (GHG) emissions produced per unit of fuel, typically expressed as grams of CO2 equivalent per megajoule (gCO2e/MJ). These scores take into account emissions throughout the entire lifecycle of the fuel—from feedstock production through processing, transportation, and eventual combustion. A lower CI score indicates a more environmentally friendly biofuel, making it increasingly important for farmers engaged in biofuel production to understand and optimize these scores (California Air Resources Board (CARB, 2021). More conversions can be calculated here: https://www.epa.gov/energy/greenhouse-gas-equivalencies-calculator. A carbon intensity score of zero would be carbon neutrality, meaning that the farm sequesters or traps the same amount of carbon that it is emitting while growing a feedstock (e.g., corn or soybeans).

How are Carbon Intensity Scores Calculated?

Calculating carbon intensity scores involves several key steps:

• Lifecycle Assessment (LCA): This is a comprehensive approach that evaluates emissions at each stage of the fuel’s lifecycle. It includes factors such as land use changes, agricultural practices, and energy consumption (Wang et al., 2015).
• Data Collection: Accurate data on input materials, agricultural practices, and emissions is essential. Farmers need to provide information about crop inputs (e.g., fertilizers, pesticides), energy used in production, and any land-use changes. -Modeling Emissions: Different models use specific methodologies to estimate emissions from various stages. The chosen model will significantly affect the resulting carbon intensity score.

Key Models for Calculating Carbon Intensity Scores__

California Air Resources Board (CARB) Model The CARB model is a well-established framework for calculating CI scores, particularly for fuels used in California’s Low Carbon Fuel Standard (LCFS). This model takes a comprehensive lifecycle approach and considers multiple factors:

• Feedstock Production: Emissions associated with land preparation, fertilization, irrigation, and harvesting.
• Processing: Emissions from converting feedstocks into ethanol, including energy use in distillation and purification.
• Transportation: Emissions from moving feedstocks to processing facilities and transporting finished ethanol to markets.

CARB provides a calculator that allows producers to input specific data about their practices, resulting in an accurate CI score that reflects their unique operations (CARB, 2021).

GREET Model

The GREET model, developed by Argonne National Laboratory, is another prominent tool for estimating carbon intensity. GREET stands for Greenhouse gases, Regulated Emissions, and Energy use in Technologies. It provides a detailed analysis of various fuel pathways, including ethanol. Key features of the GREET model include:

• Flexibility: Users can model a wide range of feedstocks, energy inputs, and production methods.
• Detailed Analysis: GREET provides comprehensive data on emissions from feedstock cultivation, processing, and end-use, allowing for a thorough lifecycle assessment.
• User-Friendly Interface: While the model is complex, it offers a user-friendly interface that enables farmers and producers to calculate their CI scores by inputting relevant data (Wang et al., 2021).

How Can Farmers Calculate Their Carbon Intensity Scores For Free?

Farmers can leverage both the CARB and GREET models to calculate their CI scores effectively. Here’s a step-by-step approach to explore the GREET model:

• Step 1: Gather Data: Collect detailed information about your farming practices, including: type and amount of fertilizers used, tillage practices, cover crop use, and crop yields.
• Step 2: Go to Iowa State University Extension and Outreach site: https://www.extension.iastate.edu/agdm/crops/html/a1-80.html and download the AgDM File A1-80 Decision Tool excel file.
• Step 3: Fill out the information in the spreadsheet in the Box 1 State and County and Box 2 Farming Practices. Fill in the left side of your current practices and fill in the right side with practice you may be willing to implement to lower your score.
• Step 4: Review the results. In box 3, you can view your results and compare current to your changed farming practices scores. Box 4 shows your estimated reduction factor and then the tax credits based on current and new farming practices. Lastly, box 5 shows the amount of a potential tax credit which could be passed from the biofuel producer to the grower based on percentages.

Conclusion:

Understanding carbon intensity scores is essential for farmers involved in biofuel production, particularly ethanol. By utilizing models like CARB and GREET, farmers can calculate their scores, identify areas for improvement, and implement sustainable practices. This proactive approach not only benefits the environment but can also enhance profitability in a market that increasingly values low-carbon fuel sources. By embracing these changes, farmers can play a crucial role in the transition toward even more sustainable biofuel production.

While waiting on further guidance on 45Z and the biofuels opportunities check out ForGround by Bayer to generate carbon income from your current and historical conservation efforts. ForGround has flexible agreements and is compatible with other programs.

References: *California Air Resources Board (CARB). (2021). California’s Low Carbon Fuel Standard: Carbon Intensity Values. Retrieved from CARB website. Wang, M., et al. (2015). Well-to-Wheels Energy Use and Greenhouse Gas Emissions of Ethanol from Corn, Sugarcane, and Cellulosic Biomass. Argonne National Laboratory. Wang, M., et al. (2021). GREET Model: Analyzing the Life-Cycle Energy Use and Greenhouse Gas Emissions of Fuels. Argonne National Laboratory.