New Study Finds California’s Indirect Land Use Change Score for Ethanol Is Obsolete

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November 06, 2025

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(Renewable Fuels Association) As the California Air Resources Board (CARB) prepares to hold a Biofuels and Land Use Change Public Forum tomorrow (November 6, 2025), a comprehensive new report from Life Cycle Associates, Advances in Estimation of Land Use Change Emissions Associated with Ethanol, shows that CARB’s decade-old estimate of hypothetical indirect land use change (ILUC) associated with ethanol is obsolete and should be revised.

California last conducted an analysis of ILUC in 2014 and 2015, when economic models were less refined for the purpose of estimating land use change and limited historical data were available for the period when the Renewable Fuel Standard (RFS) and the California Low Carbon Fuel Standard (LCFS) had been in effect.

According to Life Cycle Associates, “The cumulative effect of methodological improvements has been a steady reduction in estimated GHG emissions from corn ethanol land use change, producing results that are more consistent with observed global market behavior.” After extensively reviewing the evolution of models and emissions factor estimates, they conclude, “These improvements have allowed for a more nuanced and accurate assessment of how modeled biofuel shocks in response to different policies affect land use and associated GHG emissions. A key outcome of these analysis efforts is a reduction in predicted GHG emissions from LUC associated with corn ethanol.”

They also state, “Analysts recommend using the [Global Trade Analysis Project, or GTAP] 2017 model for its latest data and refinements.”

This is more than an academic exercise, noted the Renewable Fuels Association. CARB applies its decade-old ILUC penalties to every gallon of corn- and sorghum-based ethanol sold into California, with no evidence that such land use changes have actually occurred. Importantly, U.S. cropland area has declined since the RFS was expanded in 2007, according to both the USDA Census of Agriculture and the EPA. And, as detailed in RFA comments to CARB earlier this year, the corn area needed to meet California ethanol demand has decreased by more than 700,000 acres—or 20 percent—since the LCFS program began in 2011. Considering this, ILUC scoring artificially affects demand and reduces the market value of ethanol, based purely on flawed, obsolete, and speculative modeling results.

“RFA calls on the California Air Resources Board to fundamentally rethink its outdated, hypothetical ILUC penalties assigned to ethanol, for the reasons substantiated in this study. Real-world experience and empirical data show that the amount of cropland needed to satisfy California ethanol demand continues to trend downward, as crop yields increase and ethanol producers get more renewable fuel from each bushel,” said RFA President and CEO Geoff Cooper. “It is imperative that tomorrow’s CARB forum be the start of a process to comprehensively re-evaluate the agency’s flawed approach to ILUC. Moreover, given the concerning prevalence of forum speakers who have consistently taken anti-biofuel stances, CARB must commit to using the best available science in setting new values.” The study is available here. READ MORE

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Renewable Fuels Association calls for updates to California ILUC, cites study (Quantum Commodity Intelligence)
Lessons Learned from 18 years of Arguing About Indirect Land Use Change (Union of Concerned Scientists)

Excerpt from Union of Concerned Scientists: Going forward, directly regulating the amount of vegetable oil or other resources used to make biofuels may be a more effective way to structure a policy safeguard than the current ILUC framework of adjusting CI scores.

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The primary LCFS safeguard to address concerns about land use change is the inclusion of an estimate of land use change emissions (called indirect or induced land use change emissions or ILUC) in the carbon intensity (CI) assigned to crop-based biofuels. When this approach was initially proposed in 2007 by Alex Farrell and Dan Sperling[1], it was offered as a short-term measure until an “internationally accepted methodology for accounting for land use change” could be developed. Unfortunately, no consensus on methodology has been reached, and it appears increasingly unlikely it ever will.

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In 2022, I served on a committee of the National Academies of Sciences, Engineering, and Medicine that reviewed Current Methods for Life-Cycle Analyses of Low-Carbon Transportation Fuels in the United States. My experience on this committee reinforced that there is not now, nor will there ever be, a consensus approach in the expert community on how to do lifecycle analysis of transportation fuel. One important finding of the committee was that CI scores used for policies like the LCFS combine two dissimilar kinds of lifecycle analysis, one focused on attributing responsibility for emissions to individual actions and actors in the biofuel supply chain (called an attributional analysis), and a second that evaluates the global consequences of a policy or change (called a consequential analysis). The resulting CI score is a hybrid that does not answer any well-defined question. An alternative approach that resolves this methodological problem is to use different types of analysis for different elements of the policy, with a consequential analysis used to shape decisions of fuel producers, and a consequential analysis used to inform safeguards that directly mitigate risks or problems the analysis identifies.

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Much of the debate since 2008 over land use change has focused on corn ethanol. But for the last decade, most of the growth of biofuel consumption in the US has been from vegetable oil-based biofuels like biodiesel and renewable diesel. A new analysis by Chen, Sexton and Smith from UC Davis and Berkeley finds that that using vegetable oils for biofuel accelerates tropical deforestation and increases carbon emissions. This new analysis takes a different approach than GTAP, relying more heavily on empirical data to reduce the dependence of the results on assumptions and model structure. They find that the global expansion of bio-based diesel made from vegetable oil has fueled massive deforestation in Indonesia and Malaysia. The extent of deforestation and associated emissions outweigh any climate benefits from replacing petroleum fuels.

A key finding of the analysis of Chen, Sexton and Smith is that the extent of deforestation is largely independent of which specific source of vegetable oil is used to make biofuel. This is not surprising, because vegetable oils are all close substitutes in the global food market. But this finding is in tension with the structure of ILUC implementation, which assigns differentiated ILUC scores to specific types of feedstock.

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Not surprisingly, biofuel and vegetable oil producers reject the finding that using any source of vegetable oil has a similar impact on global markets. They argue it is unfair to hold midwestern soybean oil accountable for palm oil related deforestation in Indonesia. They have been successful at persuading federal policymakers to change the parameters of federal biofuel policies in a manner that favors major US crops, first by pressuring regulators to reduce ILUC values assigned to these crops and most recently by excluding consideration of ILUC from federal tax credits and restricting biofuel incentives to domestic fuels and feedstocks[3]. The resulting incentive structure of federal policies could have a big impact on California fuel markets in years to come. The strategies California has used to discourage the use of vegetable oil fuels will become less effective because of these changes in federal policy.

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The LCFS wisely recognizes that shifting to renewable electricity for transportation is vital to phasing out petroleum and encourages all fuel producers to reduce their supply chain emissions.

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[1] Farrell, A. E, & Sperling, D. (2007). A Low-Carbon Fuel Standard for California, Part 1: Technical Analysis. UC Davis: Institute of Transportation Studies. Retrieved from https://escholarship.org/uc/item/6j67z9w6. Farrell, A. E, & Sperling, D. (2007). A Low-Carbon Fuel Standard for California, Part 2: Policy Analysis. UC Davis: Institute of Transportation Studies. Retrieved from https://escholarship.org/uc/item/8ng2h3x7

[2] The Chen, Sexton and Smith study considered the major vegetable oils, which make up the large majority of global biofuel consumption, but they did not examine fuels made from secondary fats and oils like tallow, used cooking oil or inedible corn oil. The availability of these secondary sources is much lower than vegetable oil on a global scale, and the data on their production and use is limited. But these feedstocks make up a large share of the California bio-based diesel market. The substitution that links primary vegetable oils will also occur with tallow, used cooking oil or inedible corn oil, but not in precisely the same way. These secondary fats and oils are used to make soaps and detergents or as animal feed, and when they are diverted to fuel production, they will be replaced with other resources. Over the last few years, consumption of these feedstocks for biofuel has grown so large that the indirect impacts of their use merit further study.

[3] For more details, see EPA’s Proposal to Focus Biofuel Policy on Domestic Fuels Doesn’t Add Up. READ MORE