Results between OpenLCA and OLCA-IPC differ

Question

Hej,

For a particular project related to food, we are using a food database to do an analysis of procurement. I have been trying to connect to the database using OpenLCA and the Olca Python package with mixed success.

With help from other questions in this forum I have been able to connect, build a product system, calculate the system, and export the results of the many processes I need.

However, when comparing the results from the Olca method to calculation within OpenLCA, the results come out different.

The export from OpenLCA is more in-depth and seems to go a lot deeper than the Olca analysis. There are flows missing in every sheet in the Excel export.

So far I have tried:
1. Using various calculation methods in Olca
2. Different databases to cross-compare
3. Different Impact Assessments

I have seen similar questions but no real answers as to how to retreive the same Excel export from Olca-IPC as one can from OpenLCA, meaning the same level of detail.

You can find my code here.

Comments

I experience the same issue. I am using the ecoinvent 3.9.1 consequential upr data, OpenLCA 2.0.4 and olca 2.0.2 . I experience this issue with the original electricity processes. I create product systems within openlca and use the specific id to calculate with olca. For all electricity processes I have tested so far, I get different results in OpenLCA ('calculate') and olca. I double checked the impact method. I have the feeling, that olca does not recognize or include all provider contributions.

Answer 1

Hi, can you identify/reproduce, how the differences in the underlying inventories (i.e. included flows) are generated?

Are you 100% sure, that you use identical ...

a) ... ways of creating the product systems (provider linking, preferred process type, cut-off)

b) ...  calculation setups (same allocation method)

... in both the openLCA client as well as in olca-ipc?

Comments

Hi Julian, thanks for the replay!

Short answer; yes they are identical.
In my code I use the name of a process, but originally I went with UUIDs to ensure the processes are the same.

When I compare the export from OLCA and OpenLCA, the names and UUIDs match.

A)
For OLCA, I produce a product system from a single process and calculate for 1 functional unit.
In OpenLCA I use the direct calculation to check, but maybe I should compare it to building a product system?

I have some time to figure this out this week, I will report on what I find.

B)
I don't select an allocation method in either methods. As shown in my code there's no allocation method, and I don't select any in OpenLCA either. I only select an Impact Assessment.

Let me know if this makes it anymore clear for you!

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I think that the maual use of "direct calculation" within openLCA is the reason for you getting two different inventories. Please try to build a product system as well in openLCA, and then compare.

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I will do that and compare! I guess this is a side-question then, but what is the function of "Direct Calculation" if it's not the same as calculating the impact of a single process and 1 functional unit?

My day is kind of booked, but I will try to look that up myself also.

I will compare the results of a product system later this week.

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To answer this, I have tried every kind of calculation setup, and while there should be a difference, it shouldn't be all zeroes for many of the processes.

Also tried making a product system, that was not the issue.

Thank you for the help though!

I'm still open to other possible solutions