@article{chen2025bbd,
	title={Using Vegetable Oils for Biofuel Accelerates Tropical Deforestation and Increases Carbon Emissions},
	author={Chen, Tzu-Hui J. and Sexton, Richard J. and Smith, Aaron},
	journal={},
	url={https://www.dropbox.com/scl/fi/06ug6d414ka6mq2cqryuy/Palm_Deforestation_full_Chen_Sexton_Smith_10_30.pdf?rlkey=fpl7ugs421cu2iqfqbm1xdzvp&dl=1},
	abstract={Biofuels are promoted worldwide as a strategy to replace fossil fuels and cut greenhouse gas emissions. However, their climate benefits are uncertain because biofuel production can induce deforestation and other land use change that causes carbon emissions. Here we show that global demand for biomass-based diesel fuel between 2002 and 2018 drove the conversion of approximately 1.7 million hectares of forest to oil palm in Indonesia and Malaysia, which is about one-fifth of the total forest-to-palm expansion during this period. Using econometric models and high-resolution satellite data, we demonstrate that biomass-based diesel demand raised palm oil prices, which in turn accelerated deforestation, primarily in natural forests. The associated land-use change released more than one gigaton of CO2, giving biomass based diesel higher carbon emissions per megajoule than that of fossil diesel. These findings indicate that biofuels derived from vegetable oils have likely increased, rather than reduced, global emissions, and highlight the urgent need to shift renewable fuel policies away from crop-based feedstocks.},
	keywords={energy},
	volume={},
	year={2025}
}

Biofuels are promoted worldwide as a strategy to replace fossil fuels and cut greenhouse gas emissions. However, their climate benefits are uncertain because biofuel production can induce deforestation and other land use change that causes carbon emissions. Here we show that global demand for biomass-based diesel fuel between 2002 and 2018 drove the conversion of approximately 1.7 million hectares of forest to oil palm in Indonesia and Malaysia, which is about one-fifth of the total forest-to-palm expansion during this period. Using econometric models and high-resolution satellite data, we demonstrate that biomass-based diesel demand raised palm oil prices, which in turn accelerated deforestation, primarily in natural forests. The associated land-use change released more than one gigaton of CO2, giving biomass based diesel higher carbon emissions per megajoule than that of fossil diesel. These findings indicate that biofuels derived from vegetable oils have likely increased, rather than reduced, global emissions, and highlight the urgent need to shift renewable fuel policies away from crop-based feedstocks.

@article{wu2025saf,
	title={Policy Options to Achieve US Sustainable Aviation Fuel Targets},
	author={Wu, Mengying and McCormack, Kristen and Scott, William A. and Smith, Aaron and Zhang, Jingran and Stock, James H.},
	journal={NBER Working Paper},
	url={https://www.dropbox.com/scl/fi/d3ed4953m6bmzzposmg0h/SAF_Wu_etal.pdf?rlkey=dfh1yjad3tyumlnbdg93w5dyv&st=q0d9cptj&dl=1},
	abstract={Decarbonizing aviation in the short term will likely entail replacing large quantities of petroleum jet fuel with sustainable aviation fuels (SAFs), which are predominantly biofuels. In the United States, biofuels are currently used as substitutes for gasoline and diesel in road transportation and are supported by a complex set of federal and state policies including the Renewable Fuel Standard (RFS), state low carbon fuel standards, and state and federal tax credits. Policies promoting SAF therefore interact with surface transport biofuel policies. In this paper, we use a new detailed partial equilibrium model of road and air transportation fuel markets to compare various policy options designed to achieve a target of 3 billion gallons of SAF by 2030. Our results suggest that the target is attainable with current technology but not with current policy. Several potential federal policies, including modifications to the existing RFS, a federal SAF tax credit, or a clean aviation standard could meet the 3 billion gallon target with similar emissions reductions and costs but different incidence. The lowest cost policy we study entails replacing all current biofuels policies with a modest carbon tax on fossil transportation fuels paired with a SAF tax credit.},
	keywords={energy},
	volume={34326},
	year={2025}
}

Decarbonizing aviation in the short term will likely entail replacing large quantities of petroleum jet fuel with sustainable aviation fuels (SAFs), which are predominantly biofuels. In the United States, biofuels are currently used as substitutes for gasoline and diesel in road transportation and are supported by a complex set of federal and state policies including the Renewable Fuel Standard (RFS), state low carbon fuel standards, and state and federal tax credits. Policies promoting SAF therefore interact with surface transport biofuel policies. In this paper, we use a new detailed partial equilibrium model of road and air transportation fuel markets to compare various policy options designed to achieve a target of 3 billion gallons of SAF by 2030. Our results suggest that the target is attainable with current technology but not with current policy. Several potential federal policies, including modifications to the existing RFS, a federal SAF tax credit, or a clean aviation standard could meet the 3 billion gallon target with similar emissions reductions and costs but different incidence. The lowest cost policy we study entails replacing all current biofuels policies with a modest carbon tax on fossil transportation fuels paired with a SAF tax credit.

@article{irwin2025delivery,
	title={Was Allen Paul Right? Liquidation Bias in Commodity Futures Markets},
	author={Irwin, Scott H and Sanders, Dwight R and Smith, Aaron and Yan, Lei},
	url={https://www.dropbox.com/scl/fi/yva87gv7becqtybsm6pfp/Liquidation-Bias_07172025.pdf?rlkey=205vwhxsfobdry0nbxcwtgudm&st=uimr4898&dl=1},
	abstract={This study examines liquidation bias—the systematic rise in nearby commodity futures prices relative to deferred contracts before expiration—using 27 U.S. commodity futures contracts from 1990-2021.  We find spreads increase 0.65% over the final 15 trading days, with strongest effects in grains (0.94\%) and livestock (1.75\%).  The phenomenon persists across market conditions and changes in trading technology, suggesting it is driven by contract design.  Evidence supports delivery options as the primary driver, particularly in markets with seller-only delivery initiation.  These findings highlight important trade-offs in futures contract design and demonstrate how embedded options systematically affect commodity futures pricing, with implications for analyzing hedging effectiveness and market efficiency.},
	keywords={agriculture},
	year={2025}
}

This study examines liquidation bias—the systematic rise in nearby commodity futures prices relative to deferred contracts before expiration—using 27 U.S. commodity futures contracts from 1990-2021. We find spreads increase 0.65% over the final 15 trading days, with strongest effects in grains (0.94%) and livestock (1.75%). The phenomenon persists across market conditions and changes in trading technology, suggesting it is driven by contract design. Evidence supports delivery options as the primary driver, particularly in markets with seller-only delivery initiation. These findings highlight important trade-offs in futures contract design and demonstrate how embedded options systematically affect commodity futures pricing, with implications for analyzing hedging effectiveness and market efficiency.

@article{bushnell2023lcfs,
  title={Forecasting Credit Supply Demand Balance for the Low-Carbon Fuel Standard Program},
  author={Bushnell, James and Lade, Gabriel and Smith, Aaron and Witcover, Julie and Xiao, Wuzheqian},
	url={https://files.asmith.ucdavis.edu/LCFS_report_2023_Final_Aug.pdf},
	abstract={In this report, we present our projections for the expected supply of and demand for Low Carbon Fuel Standard (LCFS credits) through 2030, as well as through 2035, based on potential changes to program stringency.  Our main approach is to apply time-series forecasting methods to project the expected demand for transportation fuels and combine that with the expected evolution of fuel prices and carbon intensities as well as complementary policies' impact on the fuel mix. Our results imply that the program can accommodate a relatively aggressive target of a 43\% reduction by 2035, but only if everything breaks right and many best-case outcomes arise toward the middle of the next decade.  By contrast, if ZEV penetration falls well below targets, the program could reach cumulative deficits of 60 to 100 MMT by 2035.  Our median forecast of our baseline scenario, targeting 30\% carbon intensity reduction by 2030 and 43\% by 2035, forecasts a small but significant cumulative deficit by 2035.},
	keywords={energy},
  year={2023}
}

In this report, we present our projections for the expected supply of and demand for Low Carbon Fuel Standard (LCFS credits) through 2030, as well as through 2035, based on potential changes to program stringency. Our main approach is to apply time-series forecasting methods to project the expected demand for transportation fuels and combine that with the expected evolution of fuel prices and carbon intensities as well as complementary policies' impact on the fuel mix. Our results imply that the program can accommodate a relatively aggressive target of a 43% reduction by 2035, but only if everything breaks right and many best-case outcomes arise toward the middle of the next decade. By contrast, if ZEV penetration falls well below targets, the program could reach cumulative deficits of 60 to 100 MMT by 2035. Our median forecast of our baseline scenario, targeting 30% carbon intensity reduction by 2030 and 43% by 2035, forecasts a small but significant cumulative deficit by 2035.

@article{mazzone2022passthrough,
  title={Pass-Through of Alternative Fuel Policy Incentives: Evidence from Diesel and Biodiesel Markets, the U.S. Renewable Fuel Standard, and Low Carbon Fuel Standards in California and Oregon},
  author={Mazzone, Daniel and Smith, Aaron and Witcover, Julie},
	url={https://files.asmith.ucdavis.edu/NCST_Pass_Through.pdf},
	abstract={Biodiesel and hydrotreated renewable diesel (RD)—or collectively biomass-based diesel (BBD)—have become integral components of compliance with policies aiming to reduce U.S. transportation sector greenhouse gas emissions. Such policies include the U.S. Renewable Fuel Standard (RFS), California’s Low Carbon Fuel Standard (LCFS), and Oregon’s Clean Fuel Program (CFP). These policies, along with a federal Blender’s BBD Tax Credit (BTC), provide financial incentives for BBD. In this white paper, we study pass-through of implicit taxes and subsidies, introduced by federal and state policies, to a variety of diesel and soy biodiesel fuel prices in the context of the U.S. diesel sector, focusing on fossil diesel and soy biodiesel. We apply time series methods techniques to estimate how a variety of diesel fuel price spreads across the country and in California and Oregon responds to changes in the implicit taxes placed on petroleum diesel and the implicit subsidies awarded to biodiesel. The results presented in this paper point to some inefficiencies in the RFS, LCFS, and CFP. The primary contribution of this paper was providing the first set of estimates of pass-through of LCFS implicit taxes and subsidies, and doing so for the diesel sector, a critical player in LCFS compliance.},
	keywords={energy},
  year={2022}
}

Biodiesel and hydrotreated renewable diesel (RD)—or collectively biomass-based diesel (BBD)—have become integral components of compliance with policies aiming to reduce U.S. transportation sector greenhouse gas emissions. Such policies include the U.S. Renewable Fuel Standard (RFS), California’s Low Carbon Fuel Standard (LCFS), and Oregon’s Clean Fuel Program (CFP). These policies, along with a federal Blender’s BBD Tax Credit (BTC), provide financial incentives for BBD. In this white paper, we study pass-through of implicit taxes and subsidies, introduced by federal and state policies, to a variety of diesel and soy biodiesel fuel prices in the context of the U.S. diesel sector, focusing on fossil diesel and soy biodiesel. We apply time series methods techniques to estimate how a variety of diesel fuel price spreads across the country and in California and Oregon responds to changes in the implicit taxes placed on petroleum diesel and the implicit subsidies awarded to biodiesel. The results presented in this paper point to some inefficiencies in the RFS, LCFS, and CFP. The primary contribution of this paper was providing the first set of estimates of pass-through of LCFS implicit taxes and subsidies, and doing so for the diesel sector, a critical player in LCFS compliance.

@article{pouliot2017rin,
  title={RIN Pass-Through at Gasoline Terminals},
  author={Pouliot, Sebastien and Smith, Aaron and Stock, James H},
	url={https://www.dropbox.com/s/52yzs17hksxe0z9/Pass-through_Latest.pdf?dl=1},
	abstract={Wholesale suppliers at fuel terminals blend gasoline with ethanol to create finished gasoline. Under the US Renewable Fuel Standard (RFS), this blending activity is subsidized through a renewable fuel credit, known as a RIN. We estimate whether these suppliers, known as rack sellers, pass through the value of RINS. We find complete pass through in some locations and settings and not others. We argue that the incomplete pass-through we find stems from lack of salience about how the subsidy affects rack margins. If rack sellers have price-setting power in the RIN market, which is plausible, then the incomplete pass through we find creates an incentive for them to drive up RIN prices thereby raising compliance costs.},
	keywords={energy},
  year={2017}
}

Wholesale suppliers at fuel terminals blend gasoline with ethanol to create finished gasoline. Under the US Renewable Fuel Standard (RFS), this blending activity is subsidized through a renewable fuel credit, known as a RIN. We estimate whether these suppliers, known as rack sellers, pass through the value of RINS. We find complete pass through in some locations and settings and not others. We argue that the incomplete pass-through we find stems from lack of salience about how the subsidy affects rack margins. If rack sellers have price-setting power in the RIN market, which is plausible, then the incomplete pass through we find creates an incentive for them to drive up RIN prices thereby raising compliance costs.