Question

OpenLCA crushes at the calculation step. The same happens when I try to export the results into excel. Why does this happen and what should I do?

I am using the Ecoinvent database.

Answer 1

(you maybe mean "crashes") - openLCA is quite stable but has some requirements that need to be met, especially regarding memory available, and some calculations (the direct calculation, without product system) require specific structures in databases.

-> To help you more, information about the openLCA version you use and about the memory you have allocated in openLCA would be useful, and also if you use an "untouched" ecoinvent databases, which one, and / or if you are using a modified version, and if this is the case, what is the validation result for this database.

Thank you!

Andreas

Comments

Thank for your answer.

I realized that I didn't provide enough information about the "crush". In reality, the app just shuts down without warning when I try to calculate a product system. Sometimes the calculation will be successful after the 2nd or 3rd time.

I am using Ecoinvent v3.10 EN15804GD for Unit Processes and I have already expanded the memory.

About "modified version", do you mean that someone might have altered the data?

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thank you - what do you get when you validate the database? I meant that you maybe changed or added something in the database.

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I get some errors for elementary flows with the message "elementary flow is used as input and output of process".

What does it mean?

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It means as it is written: that some elementary flows are used as an input in some processes and as an output in other processes. Ideally, elementary flows are either inputs or outputs only. In the default "untouched" Nexus version of ecoinvent 3.10 EN15804GD we don't have that validation errors, so maybe these elementary flows are inside one of your own processes/models or they stem from data sets that you have imported?

You can click on that elementary flows and see in which processes they are used. This should not be the reason for your crash, but maybe you imported some databases or some data sets that have errors and which will create the crash? The "untouched" database version works fine. We would need more information.

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But again: which openLCA version are you using, how do you calculate, and how much memory is available for openLCA? Thank you!

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I am using openLCA v2.2.0 and the calculation properties are below:

1. Allocation method: As defined in processes
2. Impact assessment method: EN 15804+A2 (EF 3.1)
3. Calculation type: Lazy/On demand
4. Regionalized calculation

I have expanded the memory to 30 GB

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The new regionalization feature directly inside the software needs more memory than standard/unregionalized calculations because the whole database will be regionalized "live" during the calculations. Your memory settings should be sufficient, and I cannot reproduce any issues, since I never encountered this before. Just to be sure: You also have enough "real" RAM storage in your PC/Laptop, because you can set more in the software than what is physically available?

You can also calculate without regionalization, because the EN15804+A2 add-on impact methods are not yet regionalized, except you want to analyze the regionalized inventory results (without regionalized impacts). Typically without regionalization during the calculations, only about 4GB - 6GB are needed for the whole ecoinvent database.

Answer 2

You should probably update your openLCA version. Older versions can crash when there are zero value product outputs or waste inputs in your model (which is not a valid model then because processes are scaled by linking these flows; note that this can also happen when formulas evaluate to zero; also note that it is absolutely fine to have zero value product inputs or waste outputs on the other side, so you may need to rethink your model). The validation in newer openLCA version should also report such flows.