MIT22_081JF10_lec20b

MIT22_081JF10_lec20b - Life Cycle Analysis With examples...

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Life Cycle Analysis With examples from biofuel analysis Sustainable Energy 18 th November 2010
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Outline of Presentation •± Introduction to Life Cycle Analysis (LCA) •± LCA Basics •± Examples and challenges to implementation –± Corn Ethanol –± Cellulosic Ethanol –± Cellulosic Biofuels •± Illuminating Biofuel Trade-offs •± Consideration of Biofuel Policy
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Introduction to LCA What is LCA? A system analysis methodology (remember toolbox 4?) “cradle-to-grave analysis” Recycle Wastes Energy Production of Raw Materials Manufacturing Process Use of Product Disposal Emissions Wastes Wastes Wastes
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Components of LCA Inventory Quantification of energy and raw material requirements, emissions, effluents, and wastes i.e. mass and energy balances are integrated over each process in system Impact Assessment Values can be assigned to effects for quantification Improvement Systems can then be optimized with respect to parameters from impact assessment
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Why is LCA methodology Useful? •± Many parameters we are interested in don’t occur in just one step of a product’s lifecycle Carbon dioxide emissions from Coal-to-Liquid fuels. •± Optimizing one production step doesn’t mean system is optimal. –± Hydrogen as a transportation fuel •± Lifecycle analysis is intended to be used to optimize the aggregate outcomes
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Allow for comparison of potential products: MacDonald’s - Styrofoam or paper? Trees (natural?) Oil (bad?) Chemicals (worse) Paper (good ?) Styrofoam (??) Chlorine or Peroxide Benzene + C 2 H 4 + etc. Pulp Acid or Alkali CFCs Paper McD Hard to recycle CO 2 Styrene PCBs + Pentane Dioxins Plastic coating Polystyrene foam Water Wastewater Landfill Trash Recycle Oil
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Life-Cycle Analysis - approach •± Define “cradle-to-grave” alternative systems •± Set system boundary conditions •± Set time basis (snapshot of industry in time vs. one life cycle of representative product) •± Identify impacts of interest to decision-makers Costs, air pollution, GHG emissions, wastes, resource depletion, etc. •± For each portion of the life-cycle, estimate the impacts of interest •± Assess overall tradeoffs, considering uncertainties •± Identify major sources of adverse impact and assess improvements
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Life Cycle Analysis Software Dedicated Packages GaBi Umberto DIY (for simple cases) Excel Matlab
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Life Cycle Analysis for Energy Systems •± Major process steps Resource extraction/ production –± transport Fuel/electricity production –± Distribution –± end-use •± Important Parameters –± Emissions –± Useful work –± Costs •± Useful simplification Most energy conversion facilities non-fuel resource use negligible.
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LCA studies for biofuels are mandated •± Text of the Energy Independence and Security Act of 2007: –± “GENERAL.—The term ‘advanced biofuel’ means renewable fuel, other than ethanol derived from corn starch, that has lifecycle greenhouse gas emissions , as determined
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MIT22_081JF10_lec20b - Life Cycle Analysis With examples...

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