Allocation is extremely significant in the LCAs involving co-products. It also has significant impact on final result/outcome of the study.
Its like - You went to a tailor for getting a shirt stitched and your input was a cloth (4 meter) for shirt. The output by tailor was a Shirt (Product -3.9 m) + Hankerchief (co-product 0.1m). Therefore, if the burdens of making shirt considers allocation then 97.5% burdens would be allocated to shirt and 2.5% to Hankerchief. If you did not do allocation then 100% burdens would be assigned to shirt (which would be unfair).
I tried to explain in very simple manner, and of course there would be several rules that comes in play when you do a real LCA.
Hope this helps!
Madam,
Beautiful explanation indeed. I got your point.
Can you suggest me some literature to build my foundation on LCA and understand its intricacies and nuances, especially related to RETs.
I would be grateful.
ISO is "The Bible" for LCA practitioners. Read both ISO 14040 and 14044 thoroughly.
Expertise will built with experience and as you would build models and do more projects.
All the best!
In the case of a t-shirt and handkerchief, can you explain what is system expansion? How would the environmental burden be calculated?
Anju Baroth excellent example about shirt and hankerchief! Thanks! In a follow-up question, how would you avoid the allocation in your example?
Jenny L. Victoria Allocation can be avoided by system expansion. It means your system takes credit for making the co-products.
For ex: During the production of vegetable oil (lets say Soya) you also get waste product (or co-product) as Soya meal. This Soya meal is used as protein feed for the animals.
In case of LCA Model with allocation the outputs would be following
Vegetable Oil - 0.6 Kg (Allocation - 60%)
Soya Meal - 0.4 Kg (Allocation - 40%)
When you do system expansion the outputs would be following
Vegetable oil - 1 Kg
Avoided Burden - 0.4 kg
Therefore, in system expansion your system or product takes credit for avoiding the burdens that would have been created if the co-product was manufactured/produced on its own in a separate industrial/other process. Making it separately would have created environmental burdens which are now avoided due to the main product (vegetable oil in this case) production. Therefore, your prouduct takes credit/benefit for avoiding the burden.
The numbers in the above example are hypothetical.
Hope it helps!
Please refere ISO guidelines or other papers on system expansion for more clarity.
Anubhuti Bhatnagar I saw your message today. Hope the above explanation is still relevant for you!
Anju Baroth thanks! Yes the explanation is still relevant for me.
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