Abstract  BT16 is the third DOE-sponsored report to evaluate biomass resource availability in the conterminous United States. Each report addressed different goals. The 2005 Billion-Ton Study (BTS) was a strategic assessment of the potential biophysical availability of biomass. It identified the potential to produce more than one billion tons per year of agricultural and forest biomass sources—sufficient to produce enough biofuel to displace 30% of then-current petroleum consumption. However, this biophysical potential was not restricted by price, which is a key factor in the commercial viability of bioenergy and biofuels strategies. The 2011 U.S. Billion-Ton Update (BT2) evaluated the availability of biomass supply as a function of price. Employing an economic model to simulate potential biomass supply response to market demands, BT2 evaluated the potential economic availability of biomass feedstocks under a range of offered prices and yield scenarios between 2012 and 2030. It again projected the potential for more than 1 billion dry tons of biomass per year to be potentially available by 2030, assuming market prices of $60 per dry ton at the farmgate or roadside (i.e., after harvest, ready for delivery to a processing facility). This report (BT16) builds on previous research to address key questions: • What is the potential economic availability of biomass resources using the latest-available yield and cost data? • How does the addition of algae, miscanthus, eucalyptus, wastes, and other energy crops affect potential supply? • With the addition of transportation and logistics costs, what is the economic availability of feedstocks delivered to the biorefinery?

Abstract  The Renewable Fuel Standard (RFS) specifies the use of biofuels in the United States and thereby guides nearly half of all global biofuel production, yet outcomes of this keystone climate and environmental regulation remain unclear. Here we combine econometric analyses, land use observations, and biophysical models to estimate the realized effects of the RFS in aggregate and down to the scale of individual agricultural fields across the United States. We find that the RFS increased corn prices by 30% and the prices of other crops by 20%, which, in turn, expanded US corn cultivation by 2.8 Mha (8.7%) and total cropland by 2.1 Mha (2.4%) in the years following policy enactment (2008 to 2016). These changes increased annual nationwide fertilizer use by 3 to 8%, increased water quality degradants by 3 to 5%, and caused enough domestic land use change emissions such that the carbon intensity of corn ethanol produced under the RFS is no less than gasoline and likely at least 24% higher. These tradeoffs must be weighed alongside the benefits of biofuels as decision-makers consider the future of renewable energy policies and the potential for fuels like corn ethanol to meet climate mitigation goals.

Abstract  The Working Group I contribution to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) provides a comprehensive assessment of the physical science basis of climate change. It builds upon the Working Group I contribution to the IPCC’s Fourth Assessment Report in 2007 and incorporates subsequent new findings from the Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation, as well as from research published in the extensive scientific and technical literature. The assessment considers new evidence of past, present and projected future climate change based on many independent scientific analyses from observations of the climate system, paleoclimate archives, theoretical studies of climate processes and simulations using climate models.

Abstract  With the goal of understanding environmental effects of a growing bioeconomy, the U.S. Department of Energy (DOE), national laboratories, and U.S. Forest Service research laboratories, together with academic and industry collaborators, undertook a study to estimate environmental effects of potential biomass production scenarios in the United States, with an emphasis on agricultural and forest biomass. Potential effects investigated include changes in soil organic carbon (SOC), greenhouse gas (GHG) emissions, water quality and quantity, air emissions, and biodiversity. Effects of altered land-management regimes were analyzed based on select county-level biomass-production scenarios for 2017 and 2040 taken from the 2016 Billion-Ton Report: Advancing Domestic Resources for a Thriving Bioeconomy (BT16), volume 1, which assumes that the land bases for agricultural and forestry would not change over time. The scenarios reflect constraints on biomass supply (e.g., excluded areas; implementation of management practices; and consideration of food, feed, forage, and fiber demands and exports) that intend to address sustainability concerns. Nonetheless, both beneficial and adverse environmental effects might be expected. To characterize these potential effects, this research sought to estimate where and under what modeled scenarios or conditions positive and negative environmental effects could occur nationwide. The report also includes a discussion of land-use change (LUC) (i.e., land management change) assumptions associated with the scenario transitions (but not including analysis of indirect LUC [ILUC]), analyses of climate sensitivity of feedstock productivity under a set of potential scenarios, and a qualitative environmental effects analysis of algae production under carbon dioxide (CO2) co-location scenarios. Because BT16 biomass supplies are simulated independent of a defined end use, most analyses do not include benefits from displacing fossil fuels or other products, with the exception of including a few illustrative cases on potential reductions in GHG emissions and fossil energy consumption associated with using biomass supplies for fuel, power, heat, and chemicals.

Abstract  Recent analysis has highlighted agricultural land conversion as a significant debit in the greenhouse gas accounting of ethanol as an alternative fuel. A controversial element of this debate is the role of crop yield growth as a means of avoiding cropland conversion in the face of biofuels growth. We find that standard assumptions of yield response are unduly restrictive. Furthermore, we identify both the acreage response and bilateral trade specifications as critical considerations for predicting global land use change. Sensitivity analysis reveals that each of these contributes importantly to parametric uncertainty.

Abstract  Recently a number of papers have used general equilibrium models to study the economy-wide and environmental consequences of the first generation of biofuels (FGB). In this paper, we argue that nearly all of these studies have overstated the impacts of FGB on global agricultural and land markets due to the fact that they have ignored the role of biofuel by-products. Feed by-products of FGB, such as dried distillers grains with solubles (DDGS) and oilseed meals (VOBP), are used in the livestock industry as protein and energy sources. Their presence mitigates the price impacts of biofuel production. More importantly, they reduce the demand for cropland and moderate the indirect land use consequences of FGB. This paper explicitly introduces DDGS and VOBP into a global computational general equilibrium (CGE) model, developed at the Center for Global Trade Analysis at Purdue University, to examine the economic and environmental impacts of regional and international mandate policies designed to stimulate bioenergy production and use. We show that models with and without by-products reveal different portraits of the economic impacts of the US and EU biofuel mandates for the world economy in 2015. While both models demonstrate significant changes in the agricultural production pattern across the world, the model with by-products shows smaller changes in the production of cereal grains and larger changes for oilseeds products in the US and EU, and the reverse for Brazil. Models that omit by-products are found to overstate cropland conversion from US and EU mandates by about 27%.

Abstract  In 2010, the U.S. Environmental Protection Agency (EPA) released a life-cycle analysis of the greenhouse gas (GHG) emissions associated with the production and combustion of corn ethanol. EPA projected that by 2022, the emissions profile of corn ethanol from a new refinery would be 21% lower than that of an energy equivalent quantity of gasoline. Since 2010, the 21% value has dominated policy discussions and federal regulations related to corn ethanol as a renewable fuel and a GHG mitigation option. It is now 2018 and new data, scientific studies, technical reports, and other information allow us to examine the emissions pathway corn-ethanol has actually followed since 2010. Using this information, we assess corn ethanol's current GHG profile at 39-43% lower than gasoline. We also develop two projected emissions scenarios for corn ethanol in 2022. These scenarios highlight opportunities to produce ethanol with emissions that are 47.0-70.0% lower than gasoline. Many countries are now developing or revising renewable energy policies. Typically, biofuel substitutes for gasoline are required to reduce GHG emissions by more than 21%. Our results could help position U.S. corn ethanol to compete in these new and growing markets.