Energy intensity and global warming potential of corn grain ethanol production in Wisconsin (USA)

Increasing demand for renewable alternative fuels, such as ethanol, is driven by decreasing availability of fossil resources and increasing attention to climate change. Life cycle assessment (LCA) is the tool used to evaluate environmental impacts, such as energy intensity (EI) and global warming potential (GWP), from ethanol production, but the application of this tool varies greatly. The goals of this study were to enumerate the life cycle EI, net energy value (NEV), and GWP of corn grain ethanol production in Wisconsin, to explore ethanol production scenarios which differ at the treatment of the whole stillage (WS) coproduct, and to evaluate the various solutions to the multifunctionality problem which arises in LCA. In Scenario 1, all suggested solutions to the multifunctionality problem are considered by transforming WS into the animal feed dried distillers grains with solubles (DDGS). Scenario 2 avoids allocation using an integrated system which recycles the WS with an anaerobic biodigester and a combined heat and power (CHP) plant to provide electricity and steam to the ethanol refinery and returns the residue to the land as fertilizer. Based on the Scenario 1 analysis, we recommend the use of the subdivision (SD) solution to the multifunctionality problem because it enables clear comparisons between different ethanol production systems, it distinguishes between the environmental impacts from ethanol production and coproduct processing and it reduces the number of assumptions in the LCA calculations. From the comparison of both scenarios, we find that recycling the WS into electricity, heat, and fertilizer is the most environmentally beneficial coproduct use because it results in a 54% lower EI and a 67% lower GWP than the processing of WS into DDGS

On the reporting and review requirements of ISO 14044

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Standards in the classroom: a vehicle for sustainability education

Sustainable development is no longer a luxury, but a necessity. Sustainability standards and certifications are voluntary, commonly third party assessed, agreed upon norms and values relating to environmental, health, wellbeing, social, and ethical issues. From medical devices, to coffee, to fuels, sustainability standards have become an important cog (mechanism) to demonstrate and encourage sustainability leadership. Commonly these standards move beyond the traditional boundaries of manufacturing site process and site to encompass the environmental, social, and economic impacts of whole production chains. Bringing these ideas, mode of thinking, and understanding of the related standards to the classroom is challenging, but vital in pursuit of sustainability. Students of all ages are the practitioners, managers, and experts of the future. Whether they become consultants, academics, engineers, designers, politicians, government employees, or otherwise, they will shape the future of sustainability standards and sustainable development. Therefore, an understanding of standards and certification is important to equip the next generation of global citizens to help us all make sustainable choices. To achieve this, education must equip learners with the ability to interpret, apply and use standards in practice. This chapter will briefly explore the role of standards in sustainable development. The challenges of bringing these concepts and standards to the classroom at school and university level will then be explored. A series of case study simulation exercises designed address to develop an understanding of both the complex challenges of sustainability and the role of standards in sustainable development are presented. The merits, opportunities, and successes of the pedagogical approached are highlighted with a culminating in recommendations to overcome the challenges identified based on real-world experience in the classroom

Applying life-cycle assessment to low carbon fuel standards--How allocation choices influence carbon intensity for renewable transportation fuels

The Energy Independence and Security Act (EISA) of 2007 requires life-cycle assessment (LCA) for quantifying greenhouse gas emissions (GHGs) from expanded U.S. biofuel production. To qualify under the Renewable Fuel Standard, cellulosic ethanol and new corn ethanol must demonstrate 60% and 20% lower emissions than petroleum fuels, respectively. A combined corn-grain and corn-stover ethanol system could potentially satisfy a major portion of renewable fuel production goals. This work examines multiple LCA allocation procedures for a hypothetical system producing ethanol from both corn grain and corn stover. Allocation choice is known to strongly influence GHG emission results for corn-ethanol. Stover-derived ethanol production further complicates allocation practices because additional products result from the same corn production system. This study measures the carbon intensity of ethanol fuels against EISA limits using multiple allocation approaches. Allocation decisions are shown to be paramount. Under varying approaches, carbon intensity for corn ethanol was 36-79% that of gasoline, while carbon intensity for stover-derived ethanol was -10% to 44% that of gasoline. Producing corn-stover ethanol dramatically reduced carbon intensity for corn-grain ethanol, because substantially more ethanol is produced with only minor increases in emissions. Regulatory considerations for applying LCA are discussed.LCA Ethanol Bioenergy