A newly released analysis is calling into question the assumptions California uses to calculate indirect land-use change (ILUC) emissions for soy-based biodiesel and renewable diesel, concluding that the state’s methodology is out of step with current agricultural realities.
The study, commissioned by Clean Fuels Alliance America and Farmers Fueling the Future—a biofuel research initiative led by the American Soybean Association and the Iowa Soybean Association—finds that California’s ILUC values for U.S. soy-based fuels rely on outdated data and modeling that fail to reflect modern farming practices and recent scientific advancements.
Titled “Land Use Change Emissions Associated with Soybeans: Considerations for California’s LCFS,” the analysis was conducted by Life Cycle Associates and evaluates how land-use change emissions are calculated for soy-based biodiesel and renewable diesel under California’s Low Carbon Fuel Standard (LCFS). The report concludes that ILUC emissions associated with soy-based fuels are significantly lower than the values currently applied by the California Air Resources Board (CARB).
Researchers examined a range of updated inputs, including improvements in economic modeling, land-use datasets, crop yield responsiveness, international trade patterns, and carbon-stock measurements. These factors collectively paint a more accurate picture of how soybean production responds to increased demand for clean fuels.
CARB last revised its soybean ILUC value in 2018, using modeling tools and datasets that predate recent gains in agricultural productivity, precision farming, and global supply-chain efficiencies. Since that update, farming practices have continued to evolve, with growers producing more soybeans per acre while minimizing land expansion.
Using updated Global Trade Analysis Project (GTAP) modeling and more recent global data, the latest research shows ILUC values well below CARB’s current assumptions. According to the report, as modeling techniques and data inputs have improved over time, estimated ILUC emissions for soy-based biodiesel and renewable diesel have consistently declined—better matching observed land-use trends and real-world market behavior.
“This study confirms that today’s farmers are meeting growing clean-fuel demand through higher yields and responsible practices—not land expansion,” said Dave Walton, executive board member for Clean Fuels and the American Soybean Association. “CARB must modernize its approach and base its values on today’s science to accurately recognize the real carbon benefits of soy-based biodiesel and renewable diesel.”
Clean Fuels Alliance America says the findings reinforce the importance of keeping the LCFS aligned with current data as California continues working to decarbonize its transportation sector. Ensuring that lifecycle carbon intensity values reflect real-world agricultural performance, the organization notes, is critical to accurately evaluating low-carbon fuel pathways and supporting effective climate policy.
The full study is available here.
Adapted from an article shared initially by Biobased Diesel Daily. Image Credit: Flickr – United Soybean Board.