Lifecycle CO2 emissions from US bioethanol production with CCS

There is growing consensus that carbon dioxide removal (CDR) technologies – also referred to as “negative emissions” technologies (NETs) – will be part of the portfolio of strategies and technologies needed to hold the increase in the global average temperature to “well below 2 °C” (1), as agreed by parties to the Paris Agreement. The production of bioenergy with carbon capture and sequestration (BECCS) is one class of CDR technology (2), involving the capture and geologic storage of CO2 (CCS) that would otherwise be emitted to the atmosphere from use of biomass as a fuel for electricity generation or feedstock for production of liquid fuels. Use of CCS typically imposes two energy penalties that can diminish its benefits: energy is needed to separate CO2 from dilute CO2-containing mixtures (e.g. flue gas), and to liquefy CO2 so that it can be transported and injected into geologic formations. The predominant biofuel production pathway in the United States (U.S.) today is conversion of corn starch to ethanol, which generates relatively high-concentration CO2 from fermentation and dilute-CO2 from fuel combustion for process heat. In 2015, the U.S. produced approximately 53 billion liters of bioethanol from nearly 200 facilities (3) releasing approximately 40 MtCO2 of CO2 from fermentation and a further 20 MtCO2 from process heat (4). The climate benefit of applying CCS to biofuel production – and BECCS more generally – can only be accurately assessed in the context of emissions over the entire fuel production pathway, including the biomass supply chain. Few prior studies have quantified the carbon intensity of biofuels, such as ethanol, produced from processes including CCS (5–8). While previous studies consider a range of feedstocks (i.e., sugar cane, beets, and corn), none consider the emissions from direct and indirect land-use change associated with feedstock production and some use dated assumptions for key parameters, such as corn and ethanol yields (7,8). However, all conclude that, with the addition of CCS, GHG intensity of produced fuels decreases and can become negative (even without credit for displacement). In this paper, we quantify the life-cycle emissions of several corn-ethanol production pathways coupled with CCS at different process steps. Specifically, we assess the lifecycle emissions for dry-mill ethanol production with and without CCS for fermentation process emissions and for onsite boiler or cogeneration emissions. We run these scenarios for representative U.S. corn ethanol plants, and include recent estimates of indirect land use change. Finally, we do a detailed parametric sensitivity analysis of our results. 1. Sanderson BM, O’Neill BC, Tebaldi C. What would it take to achieve the Paris temperature targets? Geophys Res Lett. 2016 Jul 16;43(13):7133–42. 2. The Royal Society. Geoengineering the climate: science, governance and uncertainty [Internet]. London, UK: The Royal Society; 2009. Available from: https://royalsociety.org/topics- policy/publications/2009/geoengineering-climate/ 3. U.S. DOE. Renewable & Alternative Fuels - Data [Internet]. U.S. Energy Information Administration (EIA). [cited 2017 Jan 14]. Available from: http://www.eia.gov/renewable/data.cfm#alternative 4. U.S. EPA. EPA Facility Level GHG Emissions Data [Internet]. [cited 2017 Jan 14]. Available from: https://ghgdata.epa.gov/ghgp/main.do 5. Lindfeldt EG, Westermark MO. System study of carbon dioxide (CO2) capture in bio-based motor fuel production. 19th Int Conf Effic Cost Optim Simul Environ Impactof Energy Syst 2006. 2008 Feb;33(2):352–61. 6. Laude A, Ricci O, Bureau G, Royer-Adnot J, Fabbri A. CO2 capture and storage from a bioethanol plant: Carbon and energy footprint and economic assessment. Int J Greenh Gas Control. 2011;5(5):1220–31. 7. Möllersten K, Yan J, R. Moreira J. Potential market niches for biomass energy with CO2 capture and storage--Opportunities for energy supply with negative CO2 emissions. Biomass Bioenergy. 2003;25(3):273–85. 8. Kheshgi HS, Prince RC. Sequestration of fermentation CO2 from ethanol production. Energy. 2005 Jul;30(10):1865–71

Genomic Dissection of Bipolar Disorder and Schizophrenia, Including 28 Subphenotypes

publisher: Elsevier articletitle: Genomic Dissection of Bipolar Disorder and Schizophrenia, Including 28 Subphenotypes journaltitle: Cell articlelink: https://doi.org/10.1016/j.cell.2018.05.046 content_type: article copyright: © 2018 Elsevier Inc

Evaluating Biomass Energy Policy in the Face of Emissions Reductions Uncertainty and Feedstock Supply Risk

<p>Biofuels have received legislative support recently in California’s Low-Carbon Fuel Standard and the Federal Energy Independence and Security Act. Both discuss new fuel types, but neither provides methodological guidelines for dealing with the inherent uncertainty in evaluating their potential life-cycle greenhouse gas emissions. Emissions reductions are based on point estimates only. This work develops a Monte Carlo simulation to estimate life-cycle emissions distributions from ethanol and butanol from corn or switchgrass. Life-cycle emissions distributions for each of the modelled feedstock and fuel pairings span an order of magnitude or more. Corn ethanol emissions range from 50 to 200 g CO2e/MJ, and each feedstock-fuel pathway studied shows some probability of greater emissions than a distribution for gasoline. Potential GHG emissions reductions from displacing fossil fuels with biofuels are difficult to forecast given this high degree of uncertainty in life-cycle emissions. Incorporating uncertainty in the decision making process can illuminate the risks of policy failure (e.g., increased emissions), and a calculated risk of failure due to uncertainty can be used to inform more appropriate reduction targets in future biofuel policies. The current practice of modelling cellulosic biomass yields based on point values that have been aggregated over space and over time conceal important energy supply risks related to depending on biomass for transportation energy, particularly those related to local drought conditions. Using switchgrass as a case study, this work quantifies the variability in expected yields over time and space with a switchgrass growth model and historical weather data. Even with stable, productive states, yields vary from 5 to 20 Mg/ha. Yields are likely to be reduced with increased temperatures and weather variability induced by climate change. Thus, variability needs to be a central part of biomass systems modelling so that risks to energy supplies are acknowledged and risk mitigation strategies or contingency plans are considered. Irrigation, a potential risk mitigation strategy, can very often negate the impacts of drought, although system-wide irrigation is an expensive method to stabilize crops (costing $0.10 to$1.90/gallon). Unless many surplus acres of cellulosic crops are planted, there will be insufficient ethanol to meet the EISA targets 10 to 25% of the time under rain-fed conditions. Thinking in terms of yield ranges, not point estimates, is essential in planning a long-term energy system dependent on biomass.</p

Regional Allocation of Biomass to U.S. Energy Demands under a Portfolio of Policy Scenarios

The potential for widespread use of domestically available energy resources, in conjunction with climate change concerns, suggest that biomass may be an essential component of U.S. energy systems in the near future. Cellulosic biomass in particular is anticipated to be used in increasing quantities because of policy efforts, such as federal renewable fuel standards and state renewable portfolio standards. Unfortunately, these independently designed biomass policies do not account for the fact that cellulosic biomass can equally be used for different, competing energy demands. An integrated assessment of multiple feedstocks, energy demands, and system costs is critical for making optimal decisions about a unified biomass energy strategy. This study develops a spatially explicit, best-use framework to optimally allocate cellulosic biomass feedstocks to energy demands in transportation, electricity, and residential heating sectors, while minimizing total system costs and tracking greenhouse gas emissions. Comparing biomass usage across three climate policy scenarios suggests that biomass used for space heating is a low cost emissions reduction option, while biomass for liquid fuel or for electricity becomes attractive only as emissions reduction targets or carbon prices increase. Regardless of the policy approach, study results make a strong case for national and regional coordination in policy design and compliance pathways

Impacts of Variability in Cellulosic Biomass Yields on Energy Security

The practice of modeling biomass yields on the basis of deterministic point values aggregated over space and time obscures important risks associated with large-scale biofuel use, particularly risks related to drought-induced yield reductions that may become increasingly frequent under a changing climate. Using switchgrass as a case study, this work quantifies the variability in expected yields over time and space through switchgrass growth modeling under historical and simulated future weather. The predicted switchgrass yields across the United States range from about 12 to 19 Mg/ha, and the 80% confidence intervals range from 20 to 60% of the mean. Average yields are predicted to decrease with increased temperatures and weather variability induced by climate change. Feedstock yield variability needs to be a central part of modeling to ensure that policy makers acknowledge risks to energy supplies and develop strategies or contingency plans that mitigate those risks

Life Cycle Environmental Impacts of Wastewater-Based Algal Biofuels

Recent research has proposed integrating wastewater treatment with algae cultivation as a way of producing algal biofuels at a commercial scale more sustainably. This study evaluates the environmental performance of wastewater-based algal biofuels with a well-to-wheel life cycle assessment (LCA). Production pathways examined include different nutrient sources (municipal wastewater influent to the activated sludge process, centrate from the sludge drying process, swine manure, and freshwater with synthetic fertilizers) combined with emerging biomass conversion technologies (microwave pyrolysis, combustion, wet lipid extraction, and hydrothermal liquefaction). Results show that the environmental performance of wastewater-based algal biofuels is generally better than freshwater-based algal biofuels, but depends on the characteristics of the wastewater and the conversion technologies. Of 16 pathways compared, only the centrate cultivation with wet lipid extraction pathway and the centrate cultivation with combustion pathway have lower impacts than petroleum diesel in all environmental categories examined (fossil fuel use, greenhouse gas emissions, eutrophication potential, and consumptive water use). The potential for large-scale implementation of centrate-based algal biofuel, however, is limited by availability of centrate. Thus, it is unlikely that algal biofuels can provide a large-scale and environmentally preferable alternative to petroleum transportation fuels without considerable improvement in current production technologies. Additionally, the cobenefit of wastewater-based algal biofuel production as an alternate means of treating various wastewaters should be further explored

Tax and expenditure limits on local governments.

"M-194.""March 1995.""An information report."Authors: Daniel R. Mullins and Kimberley A. Cox.Includes bibliographical references (p. 60-61).Mode of access: Internet

Inequity in consumption of goods and services adds to racial-ethnic disparities in air pollution exposure.

Fine particulate matter (PM2.5) air pollution exposure is the largest environmental health risk factor in the United States. Here, we link PM2.5 exposure to the human activities responsible for PM2.5 pollution. We use these results to explore "pollution inequity": the difference between the environmental health damage caused by a racial-ethnic group and the damage that group experiences. We show that, in the United States, PM2.5 exposure is disproportionately caused by consumption of goods and services mainly by the non-Hispanic white majority, but disproportionately inhaled by black and Hispanic minorities. On average, non-Hispanic whites experience a "pollution advantage": They experience ∼17% less air pollution exposure than is caused by their consumption. Blacks and Hispanics on average bear a "pollution burden" of 56% and 63% excess exposure, respectively, relative to the exposure caused by their consumption. The total disparity is caused as much by how much people consume as by how much pollution they breathe. Differences in the types of goods and services consumed by each group are less important. PM2.5 exposures declined ∼50% during 2002-2015 for all three racial-ethnic groups, but pollution inequity has remained high

Assistant Director Housing and Administrative Services

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