resource flow analysis
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Resource Flow Analysis. ScottMatthews 12-712 / 19-622 Lecture 8. Administrative Issues. HW 3 Graded (avg 45) HW 4 Due Wednesday Project Updates Only 5 groups submitted plans last week. Recap of Last Time. Ecological footprint Relevant metric (equiv land use) - PowerPoint PPT PresentationTRANSCRIPT
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Resource Flow Analysis
ScottMatthews12-712 / 19-622Lecture 8
Administrative Issues
HW 3 Graded (avg 45)
HW 4 Due Wednesday
Project Updates Only 5 groups submitted plans last
week
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Recap of Last Time
Ecological footprint Relevant metric (equiv land use) Concerns/issues about data and
assumptionsGallery show
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Mass Balance
Fundamental principle of engineering / environmental engineering (law of conservation of mass)
Commoner: “everything must go somewhere”
Physical quantitiesEnergyCalories, etc.
Relevant: stocks and flows, ins and outs
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5Source: USGS
Material (Resource) Flow Analysis
Has existed for 100 years, but formalized as a modeling technique more recently Tool to link impacts with material uses Simple: materials book-keeping Complex: dynamic flow analyses
Inevitably an IN=OUT issue Is this trivial? Is it relevant? Do others realize? We tend to underestimate complexity – i.e.
simple materials in fact very complex flows
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MFA – Definition (Brunner)
A systematic assessment of stocks and flows of a material at a given space/time
Connects sources and pathways with sinks, intermediate flows
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Basic Plan for an MFA
Begin building a simple IN=OUT modelStart assembling IN, OUT flow data
Are there many more relevant IN, OUT flows?Is there a substantial stock or sink?
Do we have sufficient data to quantify them?Continue iterating as data and time allowWhen done, summarize as many disaggregate
stocks and flows as possible Typically express results “over life cycle”
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9Source: Brunner
10Source: USGS “MFA and Sustainability”
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12Source: Yale STAF Project
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Cadmium USGS Report
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Postel (1996) - Water
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Computers
What Data do we have?
What data do we need?
Can we do a “good enough” job?
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Group exercise
Split into groupsTry to do computer MFA for 2008
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18Source: USGS, Obsolete Computers, “Gold Mine,” or High-Tech Trash? Resource Recovery from Recycling
Policy Relevance of MFA
Can we track natural versus anthropogenic flows? JIE paper – Cadmium – only way to reduce is to
eliminate inflow But inflow is byproduct of Zinc; either need to
eliminate zinc production or cut off co-product Structure of such studies – and construction of the
stock/flow models – yields insightsCan we learn more about connections
between stocks and flows, our activities?
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MFA Issues
Data / methods are largest barriers (conceptually simple otherwise)
What about uncertainty?
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Sankey Diagrams
Generally used for Energy flow analyses
Implicit assumptions The diagrams concern quantity sizes that are related to
a period in time or to a functional unit, such as a product unit.
The quantity scale is proportional (i.e., twice the quantity is represented by an arrow that is twice as wide).
Inventories are not taken into account (i.e., there is no stock formation).
An energy or mass balance is maintained.
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23Source: WRI, http://www.wri.org/image/view/9529/_original
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Lead Flows 1970 (USGS)
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Lead Flows 1993
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To Dos
HW 5 coming Wednesday. Start tracking your expenses AND your
general “material/resource” flow starting tomorrow am. Will need to for HW.
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