How does "prefer default providers" work programmatically in openlca?

Question

Hello,

I'm using openlca2bw package to transfer some existing processes from openLCA to brightway2. I'm facing a situation where exchanges (i.e., flows)  without a default provider were deleted from the transferred process. 

One solution I'm thinking of is to link the default provider for those flows (after importing but before they are deleted by openlca2bw). In order to do so, I will need to understand how openLCA software handles unspecified providers. I read this post (https://ask.openlca.org/585/what-is-provider-linking-when-creating-a-new-product-system) and it seems that "If no default provider has been selected, the first process that comes along is used for linking" when we select "prefer default providers" when creating a product system. I wonder how, programmatically, "first process that comes along is used for linking" is done in openLCA and how I can recreate this mechanism in python (e.g., using olca-core).

Thanks!

Answer 1

Indeed, brightway has a simpler model and does not understand providers. To your question, the exchanges table is queried and the first process found that delivers the product is taken, so you could indeed, a bit similar as in SimaPro, concatenate product and process to make a new unique product (which is not very flexible evidently). Good luck!

Comments

Thank you Andreas. I have a follow-up question: when exporting a folder of processes (e.g., batteries) as a  JSON-LD file, the providers (processes) within that folder are retained (i.e., available from the dropdown list in the Provider column", however, those flows that had a provider from "background" database (e.g., provider for the flow of diesel from ecoinvent 3.8 cutoff) do not have provider information available after the JSON-LD file is imported to another empty database. But I wonder if the "linkage" information (e.g., UUID of the default provider) is still preserved during the export step and hence, can be retrieved using a script?
Thanks