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I am interested in calculating the total impact of "product X "and with that the contribution % / amount of each lifecycle phase (1-5, material production - component manufacturing- transport - use - EoL). With the goal of gaining data and making a image similar to this:

image 

I am using the Idemat2023 databse, and have collected data on: the amount and type of materials used for components, component weights, applied production processes, modes of transport and distances and EoL scenario. Having looked at the forum and manual I am following this structure:

1.Material production

  • I create a flow named "Lifecycle 1" with type: "Product" and unit: "Amount"
  • I create a process for it with the same name that takes the following inputs:
  • [mass] amount of [idemat material] from [idemat provider]
2.Component production
  • I create a flow named "Lifecycle 2" with type: "Product" and unit: "Amount"
  • I create a process for it with the same name that takes the following inputs:
  • 1 unit of "Lifecycle 1" from [flow provider]
  • [mass] amount of [idemat production process] from [idemat provider]
3. Transport
  • I create a flow named "Lifecycle 3" with type: "Product" and unit: "Amount"
  • I create a process for it with the same name that takes the following inputs:
  • 1 unit of "Lifecycle 2" from [flow provider]
  • [mass]*[distance] amount of [idemat transport mode] from [idemat provider]
4. Use
  • ...

5. EoL

  •  create a flow named "Lifecycle 5" with type: "Product" and unit: "Amount"
  • I create a process for it with the same name that takes the following inputs:
  • 1 unit of "Lifecycle 4" from [flow provider]
  • [mass] amount of [idemat EoL process] from [idemat provider]

I end up with 5 processes (with linked flows), for each of these processes I create a product system. Then I create a flow named "Product X lifetime" with type: "Product" and unit: "Amount". I create a process for it with the same name that takes as inputs 1 unit of lifecyles 1 though 5. Next I create a product system for "Product X lifetime" but I uncheck "auto link processes" in accordance with:  https://greendelta.github.io/openLCA2-manual/epds/calculate_impact_assessment.html. Then, in "Model graph" I manually add and link the previously created product systems for lifecyles 1-5 as stated in the manual. Afterwards I calculate the product system.

The problem I am running into regards my results. It seems like each lifecycle(1-5) is nested into the next which seemingly scales up the impact results of later lifecycles. I have tried fixing this by applying the same approach as described above but removing the: "1 unit of lifecycle X" from each process input. This looks like it fixes the issue, but I am unsure whether this is correct. 

Would love to get some insight of feedback on this, thanks in advance!

in openLCA by (140 points)

1 Answer

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by (2.2k points)

Hi,
It is slightly confusing with lifecycle 1-5. I guess you mean life cycle stages as displayed in your chart. We recently added the life cycle modelling to the manual, which can be found here: https://greendelta.github.io/openLCA2-manual/conceptualguideline/index.html, aggregated under "If you are interested in displaying impacts per life cycle stage, click here". You don't have to use nested product systems to generate the chart display above.

I hope this helps

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