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Allocation in Environmental Life Cycle Assessment

Learn about allocation procedures in environmental life cycle assessment, including system expansion and avoidance of allocation. Understand how to allocate emissions and determine the environmental impact of co-products and recycling.

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Allocation in Environmental Life Cycle Assessment

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  1. Lecture 10A: Allocation Environmental Life Cycle AssessmentPSE 476/WPS 576/WPS 595-005 Fall 2014 Richard A. Venditti Forest Biomaterials North Carolina State University Raleigh, NC 27695-8005 Richard_Venditti@ncsu.edu Go.ncsu.edu/venditti

  2. Allocation • Allocation: partitioning the input and output flows of a process or a product system between the product system under study and one or more of the other product systems (ISO 14044: 2006E)

  3. Allocation Procedures • Step 1: allocation should be avoided • Increasing the level of detail. By dividing the unit process into 2 or more sub-processes and tracking data for both separately • System Expansion. Expanding the system to include the additional functions of the related co-products Refs: Michael Hauschild, DTU

  4. Allocation Procedures • Step 2: partition the inputs and outputs between products in a way that reflects underlying physical relationships • Number of parts • Mass • Volume • Step 3: partition the inputs and outputs between products in a way that reflects other relationships between them • economic value Refs: Michael Hauschild, DTU

  5. Avoidance of Allocation: Divide the process 5 A factory makes television sets and also makes car radios. The factory utilizes 50,000 kWh every month. The electrical power used during days in which tv manufacture occurs is twice the amount than when radios are being made. In an month 8000 tv’s and 2000 radios are produced on average. What is the amount of electricity that can be attributed to a tv and a radio? The factory is closed on weekends.

  6. Avoidance of Allocation: Divide the process 6

  7. Avoidance of Allocation: System Expansion 7 • A landfill disposes of 50 tons of waste by burning and produces 550 kWh per ton. The process emits a total of 400 kg of CO2e per ton of waste burnt. Use system expansion to determine the emission per ton of waste processed for the following cases for the alternate source of electricity: • Anthracite coal • Natural Gas • Biodiesel

  8. Avoidance of Allocation: System Expansion 8

  9. Allocation Issues: Co-products: Emissions Raw Matls Power Product B System Product A 9 • Co-products Allocation: a single process produces multiple products, • Burdens can be partitioned by mass flows, volume flows, piece flows monetary values…. • Must use process/product knowledge to determine partioning method • Example for paper production: paper, Tall Oil, turpentine, electricity…

  10. Allocation Issues: Co-products: • A truck travels 800 km delivering 10,000 kg of food. The truck has the following emission .094 kg CO2e/tonne km. The following is transported: • 800 packages of spices, 0.5 kg per bag, price: $800/kg • 8000 packages of flour, 1 kg per bag, price $30/kg • 400 packages of rice, 4 kg per bag, $1/kg • Use allocation procedures to allocate the emission. Determine the emission per kg of each food product also. • By bag • By mass • By value

  11. Allocation Issues: Co-products: • Total emissions: • Total bags: • Total Mass: • Total Value:

  12. Allocation Issues: Co-products:

  13. Allocation Issues: Co-products:

  14. Allocation Issues: Recycling 14 • Recycling Allocation: a virgin product is recycled or re-used in a subsequent life (Hitchhikers guide to LCA, Baumann and Tillman, 2004) • There exists operations that are required by the virgin and the recycled products (shared operations) • Example shared operations: virgin raw material production, final disposal • Many ways to allocate the burdens of the common operations

  15. Allocation Issues: Recycling: • Cut off method: loads directly caused by a product are assigned to that product (V1 to L1, R1 to L2, R2 and W3 to L3) • Approximation with closed loop recycling. Equal burdens. All lives of a product share equal the shared operation loads. • Relative loss of quality: shared operation loads partitioned according to quality of products • Waste treatment is inevitable consequence of raw material extraction (V1 and W3 to L1) • Man made products are valuable that must be replaced by virgin resources if lost as waste (V1 and W3 to L3)

  16. Allocation Issues: Recycling 16 Use cut off, approx. of closed loop, and quality methods to calculate emissions of each product R1=R2= 3 units of emissions, U1=U2=U3=0 W3=1 unit of emissions Relative quality of products: Q1=1, Q2=0.75, Q3=0.5

  17. Allocation Issues: Recycling 17 Use cut off, approx. of closed loop, and quality methods to calculate emissions of each product

  18. Summary • Coproducts • System expansion • Divide the process • Allocation • Item, physical quantity, other quantity • Allocation factor • Allocated emissions • Recycling • Shared operations • Cut off • Loss of quality • Equal burdens

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