Best practice for mixing Cutoff System (S) and Unit (U) processes in the same openLCA project

Question

Hello,
I have a question regarding best practice when working with Ecoinvent Cutoff system models in openLCA. In many projects we need to run:

• fast screening calculations using Cutoff, System Processes (S), and

• detailed contribution analyses using Cutoff, Unit Processes (U).

Our current approach is:

1. Import both Cutoff, S and Cutoff, U datasets into the same database.

2. Keep a single foreground model, and

3. Create two product systems where we manually switch background providers (e.g., electricity, heat, transport) from S to U depending on the calculation required.

Before standardising this workflow, we would like to confirm:

1. Is this modelling approach recommended or conceptually correct according to OpenLCA's best practice?

Is it acceptable to keep S and U datasets together and choose providers depending on the required level of detail, as long as we do not mix S and U versions of the same dataset within one product system?

2. Is there any way to automate switching from S to U ?

for example via a built in featur, a bulk replace function, etc,Manual switching works but is time-consuming for large models.

Any guidance on recommended workflows would be greatly appreciated.

Thank you!

Answer 1

Interesting question, maybe though nowadys you can always use libraries - you get results in seconds (or, 1 second, depending on the computer) in unit process resolution, and your model graph is not "messed up" with generic supply chains from a generic database (ecoinvent) that you anyhow are not supposed to change.