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A recent study by DeCicco et al. (Climatic Change 138:667–680, 2016) claims that corn used for ethanol should not be considered to be inherently biogenically carbon-neutral because not all that corn was grown additional to the level otherwise. By assessing the extent of carbon neutrality of corn for ethanol using the reference point baseline approach and historical data that study concluded that the carbon intensity of US corn ethanol is 27% higher than that of gasoline. We develop a framework to determine the carbon neutrality of corn for ethanol by assessing the additional carbon uptake by crops using an anticipated baseline approach. We also apply this framework to determine the additional corn produced for ethanol and include the direct life cycle carbon emissions of only that portion of corn in the direct life cycle carbon intensity of corn ethanol. We implement this framework by integrating an economic model of the agricultural sector in the USA with a biogenic carbon model and life cycle analysis to quantify biogenic carbon uptake and direct life cycle emissions with and without corn ethanol expansion over the 2007–2027 period. We find that the combined biogenic carbon emissions and direct life cycle carbon emission intensity of corn ethanol (not including indirect land use related emissions) is 21% lower than gasoline. The lower value of this carbon intensity of corn ethanol compared with gasoline is robust to a wide range of parametric assumptions.

When the USA passed the Renewable Fuel Standards (RFS) of 2007 into law, it mandated that, by the year 2022, 36 billion gallons of biofuels be produced annually in the USA to displace petroleum. This targeted quota, which required that at least half of domestic transportation fuel be “advanced biofuels” either produced from lignocellulosic feedstocks or be a sustainable liquid fuel other than corn ethanol or biodiesel from vegetable oils, will not likely be met due to the difficulty in commercializing alternative biofuels. The number one cost to a biorefinery is the biomass feedstock cost. Thus, it is important that research into biorefinery strategies be closely coupled to advances in crop science that account for crop yield and crop quality. To reach the RFS targets, stepwise progress in biorefinery technology is needed, as the industry moves from corn ethanol toward utilizing a wider array of lignocellulose-based biomass feedstocks. In 2010, the US Department of Agriculture created five Regional Biomass Research Centers to optimize production, collection, and conversion of crops to bioenergy, thus building a network that fosters collaboration among researchers to improve the biorefinery industry. An important component of the five Regional Biomass Research Centers is the four USDA Agricultural Research Service (ARS) regional utilization laboratories located across the country. These USDA ARS labs were originally set up by their commodities, whereby, in broad terms, the Northern Lab, now NCAUR, focused on corn and soy; the Eastern Lab on oils, leather, dairy, and meats; the Southern Lab on cotton, sugars, and fibers; and the Western Lab on other grains, including wheat and specialty crops. Each lab’s traditional expertise in these respective core commodity crops has been maintained as biofuel research came to the fore, but with the addition of new crops and biotechnological expertise, these labs often collaborate with each other, as will be revealed below. This review outlines some of the recent advances from the ARS labs in developing new bioprocessing strategies required to develop bioenergy from new crop sources.

This study evaluates the economic viability of using corn to supplement sugarcane for ethanol production in Brazil. Volatility of input and output prices and their correlation due to the transmission of shocks across markets is considered in calculations of Net Present Value. Investment in a flexible mill (i.e. a mill that can process corn during the sugarcane off-season) is dominated by investment in a standard mill based on a second order stochastic dominance criterion. The latter suggests that risk-neutral and risk-averse investors may refrain from investing in a flexible plant. Downside risk associated with a flexible plant may be worsen by the US ethanol blend wall as this weakens the correlation between the price of corn and the price of inputs and outputs of the sugar complex. Reductions in capital import tariffs can offset this effect.