Environmental Life Cycle AssessmentPSE 476/WPS 576/WPS 595-005

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Fall 2014

Richard A. VendittiForest Biomaterials

North Carolina State University Raleigh, NC 27695-8005

Richard_Venditti@ncsu.eduGo.ncsu.edu/venditti

Lecture 10A: Allocation

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)

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

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

Avoidance of Allocation: Divide the process

• 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.

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Avoidance of Allocation: Divide the process

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Avoidance of Allocation: System Expansion

• 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

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Avoidance of Allocation: System Expansion

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Allocation Issues: Co-products:

• 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…

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Product A

Product B

Emissions

System

Raw MatlsPower

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

Allocation Issues: Co-products:

• Total emissions:

• Total bags:

• Total Mass:

• Total Value:

Allocation Issues: Co-products:

Item Allocation

Allocation Factor

Allocated Flow, kg CO2e

Emission kg CO2e /bag

Emission kg CO2e /kg food

Spice

Flour

Rice

Allocation Issues: Co-products:Mass Allocation Economic Allocation

Allocation Factor

Allocated Flow, kg CO2e

Emission kg CO2e /kg food

Allocation Factor

Allocated Flow, kg CO2e

Emission kg CO2e / kg food

Spice

Flour

Rice

Allocation Issues: Recycling • 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

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Primary material production

(V1)

Production of Product P1

(P1)

Use of Product P1

(U1)

Recycling of Product P1

(R1)

Production of Product P2

(P2)

Use of Product P2

(U2)

Recycling of Product P2

(R2)

Production of Product P3

(P3)

Use of Product P3

(U3)

End of life(W3)

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)

Allocation Issues: Recycling • 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

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Primary material production

(V1)

Production of Product P1

(P1)

Use of Product P1

(U1)

Recycling of Product P1

(R1)

Production of Product P2

(P2)

Use of Product P2

(U2)

Recycling of Product P2

(R2)

Production of Product P3

(P3)

Use of Product P3

(U3)

End of life(W3)

Allocation Issues: Recycling • Use cut off, approx. of closed loop, and quality methods to calculate

emissions of each product

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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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