Abstract  National-scope environmental life cycle models of goods and services may be used for many purposes, not limited to quantifying impacts of production and consumption of nations, assessing organization wide impacts, identifying purchasing hotspots, analyzing environmental impacts of policies, and performing streamlined life cycle assessment. USEEIO is a new environmentally-extended input-output model of the United States fit for such purposes and other sustainable materials management applications. USEEIO melds data on economic transactions between 389 industry sectors with environmental data for these sectors covering land, water, energy and mineral usage and emissions of greenhouse gases, criteria air pollutants, nutrients and toxics, to build a life cycle model of 385 US goods and services. In comparison with existing US models, USEEIO is more current with most data representing year 2013, more extensive in its coverage of resources and emissions, more deliberate and detailed in its interpretation and combination of data sources, and includes formal data quality evaluation and description. USEEIO is assembled with a new Python module called the 10 Model Builder capable of assembling and calculating results of user-defined input-output models and exporting the models into LCA software. The model and data quality evaluation capabilities are demonstrated with an analysis of the environmental performance of an average hospital in the US. All USEEIO files are publicly available bringing a new level of transparency for environmentally-extended input-output models. Published by Elsevier Ltd.

Abstract  Studies on the environmental analysis of biofuels by fast pyrolysis and hydroprocessing (BFPH) have so far focused only on the environmental impacts from direct emissions and have included few indirect emissions. The influence of ignoring some indirect emissions on the environmental performance of BFPH has not been well investigated and hence is not really understood. In addition, in order to avoid shifting environmental problems from one medium to another, a comprehensive assessment of environmental impacts caused by the processes must quantify the environmental emissions to all media (air, water, and land) in relation to each life cycle stage. A well-to-wheels assessment of the total environmental impacts resulting from direct emissions and indirect emissions of a BFPH system with corn stover is conducted using a hybrid life cycle assessment (LCA) model combining the economic input-output LCA and the process LCA. The Tool for the Reduction and Assessment of Chemical and other environmental Impacts (TRACI) has been used to estimate the environmental impacts in terms of acidification, eutrophication, global climate change, ozone depletion, human health criteria, photochemical smog formation, ecotoxicity, human health cancer, and human health noncancer caused by 1 MJ biofuel production. Taking account of all the indirect greenhouse gas (GHG) emissions, the net GHG emissions (81.8 g CO2eq/MJ) of the biofuels are still less than those of petroleum-based fuels (94 g CO2eq/MJ). Maize production and pyrolysis and hydroprocessing make major contributions to all impact categories except the human health criteria. All impact categories resulting from indirect emissions except eutrophication and smog air make more than 24% contribution to the total environmental impacts. Therefore, the indirect emissions are important and cannot be ignored. Sensitivity analysis has shown that corn stover yield and bio-oil yield affect the total environmental impacts of the biofuels more significantly than the biomass transportation distance and biofuel transportation distance. Integr Environ Assess Manag 2018;14:139-149. © 2017 SETAC.

Abstract  In societys quest to mitigate climate change it is important to consider potential trade-offs in climate solutions impacting other environmental issues. This analysis explores the life cycle water consumption of alternative low-carbon energy sources for transportation. Energy sources analyzed include both biofuels used in internal combustion engines and low-carbon electricity generation methods used in conjunction with electric vehicles. Biofuels considered are corn-based ethanol, soybean biodiesel, cellulosic ethanol from switchgrass, and microbial biodiesel. Electricity sources analyzed are coal with carbon sequestration, photovoltaic cells, and solar concentrators. The assessment method used is hybrid life cycle assessment (LCA), which combines materials-based process method and the economic input-output (EIO) method. To compare these technologies on an even footing the life cycle water use to propel a passenger vehicle one mile is estimated. All technologies evaluated showed an increase in water consumption compared to unleaded gasoline when water use from vehicle manufacturing was included. Scale-up calculations showed that mass adoption of electric vehicles and some configurations of algae and switchgrass systems could potentially contribute to the decarbonization of transportation with tolerable increases in overall water consumption. Irrigated crop based biofuels however were found to have significant potential impact on water resources when scaled up to macroscopic production levels. (C) 2010 Elsevier Ltd. All rights reserved.

Abstract  In 2007, the Renewable Fuels Association (RFA) conducted a survey of US ethanol production plants to provide an assessment of the current US ethanol industry. The survey covers plant operations in both corn dry mills and wet mills. In particular, it includes plant type, ownership structure, capacity, feedstocks, production volumes, coproducts, process fuel and electricity usage, water consumption, and products transportation and distribution. This report includes a summary and analysis of these results.

Abstract  'Biodiesel' is the name given to a renewable diesel fuel that is produced from fats and oils. It consists of the simple alkyl esters of fatty acids, most typically the methyl esters. We have developed a computer model to estimate the capital and operating costs of a moderately-sized industrial biodiesel production facility. The major process operations in the plant were continuous-process vegetable oil transesterification, and ester and glycerol recovery. The model was designed using contemporary process simulation software, and current reagent, equipment and supply costs, following current production practices. Crude, degummed soybean oil was specified as the feedstock. Annual production capacity of the plant was set at 37,854,118 l (10 x 10(6)gal). Facility construction costs were calculated to be US dollar 11.3 million. The largest contributors to the equipment cost, accounting for nearly one third of expenditures, were storage tanks to contain a 25 day capacity of feedstock and product. At a value of US dollar 0.52/kg (dollar 0.236/lb) for feedstock soybean oil, a biodiesel production cost of US dollar 0.53/l (dollar 2.00/gal) was predicted. The single greatest contributor to this value was the cost of the oil feedstock, which accounted for 88% of total estimated production costs. An analysis of the dependence of production costs on the cost of the feedstock indicated a direct linear relationship between the two, with a change of US dollar 0.020/l (dollar 0.075/gal) in product cost per US dollar 0.022/kg (dollar 0.01/lb) change in oil cost. Process economics included the recovery of coproduct glycerol generated during biodiesel production, and its sale into the commercial glycerol market as an 80% w/w aqueous solution, which reduced production costs by approximately 6%. The production cost of biodiesel was found to vary inversely and linearly with variations in the market value of glycerol, increasing by US dollar 0.0022/l (dollar 0.0085/gal) for every US dollar 0.022/kg (dollar 0.01/lb) reduction in glycerol value. The model is flexible in that it can be modified to calculate the effects on capital and production costs of changes in feedstock cost, changes in the type of feedstock employed, changes in the value of the glycerol coproduct, and changes in process chemistry and technology.

Abstract  Summary Conventional process-analysis-type techniques for compiling life-cycle inventories suffer from a truncation error, which is caused by the omission of resource requirements or pollutant releases of higher-order upstream stages of the production process. The magnitude of this truncation error varies with the type of product or process considered, but can be on the order of 50%. One way to avoid such significant errors is to incorporate input-output analysis into the assessment framework, resulting in a hybrid life-cycle inventory method. Using Monte-Carlo simulations, it can be shown that uncertainties of input-output? based life-cycle assessments are often lower than truncation errors in even extensive, third-order process analyses.

Abstract  There has been a large improvement in energy balance since 1995, and a small but positive improvement since 2008. There is wide variation in energy balance across refinery configurations. Refineries such as those in West Iowa, near corn supplies, livestock operations, transport infrastructure, and final markets have the best energy balance. There is a significant potential for a 30-fold improvement in energy balance by using biomass (stover)-powered refineries. Management of power and drying costs may be important to future improvements in energy balance. In some locations, wet or modified distillers’ grains (DG) marketing already increases profits and improves energy balance at the same time. Biomass power improves variable energy expenditures, and new energy policies would strengthen incentives for biomass conversion.

Abstract  Corn kernel fiber ethanol that can be produced concurrently with corn starch ethanol has recently been approved as cellulosic biofuel in the USA, suggesting that fiber ethanol could be eligible for a higher credit price than conventional starch ethanol due to its anticipated lower greenhouse gas (GHG) emissions. A life-cycle analysis was conducted to quantify ethanols GHG emissions. Here we show that fiber ethanols life-cycle GHG emissions (36-39 g CO(2)e MJ(-1)) are close to meeting the US cellulosic biofuels legislative mandate of 60% GHG emissions reduction relative to gasoline (similar to 94 g CO(2)e MJ(-1)), with slightly lower emissions under the nth plant mature fiber technology than under the state of technology (SOT). The co-product, distillers grain with solubles (DGS), can notably affect fiber ethanols GHG emissions, and this impact may need to be further examined when evidence of DGS market impacts becomes available. (c) 2018 Society of Chemical Industry and John Wiley & Sons, Ltd

Abstract  Expanding the domestic bioeconomy can help diversify the use of national resources and reduce emissions. Evaluating the sustainability of a growing bioeconomy, however, is inherently complex since it spans several sectors and supply chains. It requires a comprehensive, integrated analysis framework to assess the developments across the traditional sustainability dimensions. Further, the assessment of bioeconomy developments requires a robust baseline of historic data and trends. In this paper, we analyze the evolution of the biofuel portion of the US bioeconomy, focusing on two fuels that had an exponential growth in the last two decades: corn ethanol and soybean biodiesel. For this purpose, we created a novel time series of harmonized environmentally-extended input-output (EEIO) tables based on a publicly available model from the US Environmental Protection Agency and expanded its disaggregation to reflect the main supply chains of the biofuels sectors. The EEIO time series provides the historical evolution of these biofuels relative to the rest of the economy as well as on an energy-unit basis. We find that, except for energy use, the broader US economy declined in both resource intensity and most environmental impacts when normalized per one million dollars of gross domestic product. Deviating from this trend are freshwater ecotoxicity and human toxicity, mainly attributable to the expansion of commodity crops and the increase of domestic oil and gas extraction respectively. We also find that the biofuel industry's total socioeconomic, resource use and environmental impacts grew with their production increases over time. However, the industry's maturation and scale-up, combined with higher feedstock yields, contributed to a reduction of most impacts on an energy-unit basis over time.

Abstract  Data from the 2010 Agricultural Resource Management Survey (ARMS) and ERS cost of production accounts present a snapshot of the production costs, production practices, and characteristics related to U.S. corn production in 2010. This study found considerable variation in the operating and ownership costs for corn, ranging from an average of $1.74 per bushel for low-cost producers to $3.88 per bushel for high-cost producers. In 2010, high corn prices meant that most producers covered their corn production costs from harvest-month prices. The Heartland continues to be the major corn production region with the lowest operating and ownership costs per bushel, mainly because of the region’s high corn yields. The operating and ownership costs per bushel did not vary significantly by enterprise size where size is measured by the number of planted corn acres per farm. However, these costs per planted acre were lowest for farms with the smallest corn enterprises and highest for farms with the largest corn enterprises. Production value less operating and ownership costs per acre from organic corn production was higher than that from conventional corn production because higher prices more than offset lower yields for organic corn.