Model LCA to report impact of each phase - HOWTO (?)

Question

I have a product made of four parts: P1...P4. Of each part I know mass, manufacturing process, material, EoL scenario. I'm using the IDEMAT ecoDB.
My intention is to model the LCA in order to have the impact of each phase (PreProd, Manufacturing, Use, EoL) of each part.

How do I model the LCA in order to have an output similar to this image?

I looked at the YouTube tutorials and the ones that were closer to my use case were the PET bottle and the Scooters.

From what I gathered, I should follow this process (I will take P1 as example):

1. PRE-PRODUCTION
   I create a P1_PREPROD flow of type "Product", with "Amount" unit.
2. I create a P1_PREPROD process for it, that takes as input:
   - [mass] amount of [idemat_material] from [idemat_provider]
    
3. MANUFACTURING
   I create a P1_MANUF flow of type "Product" with "Amount" unit.
4. I create a P1_MANUF process for it, that takes as input:
   - 1 unit of P1_PREPROD flow
   - [mass] amount of [idemat_injection_molding] from [idemat_provider]
    
5. USE
   ...
6. TRANSPORT
   ...
7. EOL
   ...

Recursively, unit I end up with four product flows: P1_PREPROD, P1_MANUF, P1_TRANSPORT, P1_USE, P1_EOL. Then:

1. I create a P1_LIFECYCLE "Product" flow, "Amount" unit.
2. I create a process for it, that takes as input:
   - P1_PREPROD
   - P1_MANUF
   - P1_TRANSPORT
   - P1_USE
   - P1_EOL
3. Add this new created process to a product system
4. Run the analysis

Is that correct or am I missing something here? This all looks VERY complex to me, but it's what I understood from the videos...

Answer 1

Yes, that looks complicated indeed. There are several ways, a rather straightforward one is to build one product system for each stage, and make one process ("life cycle" or so ) where you feed all inputs from these product systems into. You need to add these LC stage product systems to a new product system with the life cycle process. This is a bit similar to your approach but you do not need the P1 etc. processes and products.

We will have analysis groups in a next release, you will be able to select processes in the model graph and their results with supply chain but without double-counting will be shown separately in the results. This will be quite useful for EPDs etc. (and in your case as well). It is already implemented but waiting for the next release which we plan still this year.

Comments

Thank you for your answer. I also found an alternate process, which is slightly less complex avoiding the russian-dolling of flows:

1. Create product flow for PP
2. Create process with PP flow as reference. Input: [mass] of [material] from [provider]

3. Create product flow for Manuf.
4. Create process with M. flow as reference. Input: [manufacturing method] applied to [mass] from [provider]

So on and so forth up to the End of Life scenario:

1. Create product flow for EoL
2. Create process with EoL flow as reference. Input: [eol scenario] applied to [mass] from [provider]
??? Question: the eol_scenario has to be an output or an input? I'd go with input but idk.

Then, finally, I create a process "Complete lifecycle", with input:
PP_Flow
Manuf_Flow
User_Flow
Transp_Flow
EoL_Flow

Assign it to a product system and run the analysis.

I arrived to this other method because I reasoned that the previous workflow would multiply the effects of previous phases, as they were included singularly in the final process. Also, in that output there was a nesting of the results of each phase into other ones, which lead to a mess in gathering data and visualizing them (I'd get that EoL was 100% of the impact, where actually X% was from Use, where Y% was from Manufacturing, where Z% was from Preproduction...)

Is this any better? Or is it wrong?

---

Hi,
we sometimes also model this way and cover it in the basic training. In the manual, you can find a similar approach for EPDs: https://greendelta.github.io/openLCA2-manual/epds/calculate_impact_assessment.html but I will add an example soon displaying modeling according to life cycle stages.

Answer 2

Hi,
we added now an example to the manual:
https://greendelta.github.io/openLCA2-manual/conceptualguideline/index.html
In the "If you are interested to display impacts per life cycle stage click here" part. You will see basically what we discussed in the other answers.

Best

Comments

Hi,
I have an additional question. I am running into a similar problem. I would like to achieve the displayed graph in the original post and follow the same approach however calculating the individual product systems P1-P2-etc does not lead to results comparable to the image.

How can I achieve this graphical depiction? Do I need to create a project comparing the separate product systems to achieve this result?

Would love to her how to approach this!

Best