I would like to use Brightway2-aggregated (bw2-agg) to generate aggregated (cradle-to-gate) LCIA scores for production activities according to the CML method. These aggregated LCIA scores shall be used for further LCA calculations, among others using ecoinvent 3.9.1, premise and the Activity Browser.
My issue concerns the creation of the unit process database as basis for the DatabaseAggregator. As I understand the bw2agg documentation, I need to set up a database with the unit processes (in my case the production activities) and its aggregated LCIA scores. For this purpose I created a excel sheet (see atteched screenshot), which I want to import in Brightway2 using the ExcelImporter. The excel sheet contains the output of the production activity (exchange type: production) as well as its LCIA impact scores (exchange type: biosphere) as exchanges.
To create a bw2 database including this activity, I need to link the biosphere exchanges to a database. Otherwise I cannot use the .write_database() function to create the bw2 database, as I have unlinked biosphere flows.
So my question is, how to link the impact scores (so the biosphere flows) to database, and to which database so that

• I have no unlinked biosphere flows,
• can use the .write_database() to set up the unit process database in bw2,
• and can use the DatabaseAggregator

In general, I use the biosphere database of ecoinvent 3.9.1. in this project, but of course it does not contain the LCIA impact score biosphere exchanges.