Monte Carlo Simulation option unavailable in product system calculation properties window

Question

I'm trying to perform a Monte Carlo Simulation with a process built in the USLCI database, but the calculation window won't allow it as an option.
I added uncertainty to flows in the process by importing the Ciroth et al data quality system for flows. Then I use the pedigree matrix to create an uncertainty distribution.
When I create a product system and click on "Calculate," the option to perform a Monte Carlo is unavailable (grey text).
How do I get the calculation setup to allow MC simulations? Am I missing a step somewhere? I'm more familiar with ecoinvent where the functionality is built in, so maybe there's some edit I need to make to the USLCI database.
For reference on versions: openLCA 2.3.0, USLCI 1.2024-10.0

Comments

I'm also running into an issue with this and troubleshooting. At this moment, I suspect that there's a problem somewhere in the model graph (like an output flow connected to the input of the same process). As a starting point you might try building out the product system using only default providers.

I'm guessing openLCA is finding the issue with the product system though and disabling Monte Carlo. Any way for us to see what flows/processes might be causing the issue?

Answer 1

Hello mrmlca,

Unfortunately, the Monte Carlo simulation is not available when using libraries at the moment. We are currently working on it and hope to include it in upcoming releases.

Regards,

François

Comments

Thank you, Andreas.
Actually, I should clarify. I do not want to run a Monte Carlo analysis on the library datasets themselves (e.g., to calculate the uncertainty inherent in the ecoinvent datasets).
What I would like to do is run a Monte Carlo analysis based on my own parameters, which I use in the LCA model. For example, the quantities of a product flow, whose provider is an ecoinvent dataset from the library.

Answer 2

Hi, can you post a screenshot? The MC simulation is agnostic to the database, in case there is no uncertainty there are no results, but the option is still offered. See here for our version of the LCA Commons database.

Thank you!

Comments

I'm seeing that in my own test. The second I add a process from a library, the option gets greyed out.