## Economic Allocation in 1.4.1

mptsang
Posts: 27
Joined: 07 May 2014 09:49

### Economic Allocation in 1.4.1

Hi There,

I have a question regarding the calculation of the economic allocation factors. Let me first start with an example pulled directly from numbers I put into openLCA:

Two outputs (both with flow property as "number of items"): Output A = 1 item, Output B = 5 items

Economic Flow Properties: Output A = 0.25 €/item, Output B = 0.66 €/item
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OpenLCA's Output of Economic Allocation Factor: Output A = 0.346, Output B = 0.654
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I am under the assumption that the economic allocation factors should be calculated as: Output A = [(Cost_A)/(Cost_A + Cost_B)], Output B = (Cost_B)/(Cost_A + Cost_B)

This would thus be:

Output A = [(1 item * 0.25 €/item)/((1 item * 0.25 €/item)+(5 item * 0.66€/item))] = 0.25/3.55 = 0.07

Output B = [(5 item * 0.66 €/item)/((1 item * 0.25 €/item)+(5 item * 0.66€/item))] = 3.3/3.55 = 0.93
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But it seems that the calculation in openLCA is done by combining Economic Flow Properties of opposite co-products:
Output A = [(1 item * 0.66 €/item)/((1 item * 0.66 €/item)+(5 item * 0.25€/item))] = 0.66/1.91 = 0.35

Output B = [(5 item * 0.25 €/item)/((1 item * 0.66 €/item)+(5 item * 0.25€/item))] = 1.25/1.91 = 0.65
====================================================================

Can you clarify my misunderstanding here?

Best,

Michael

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