Using library (ecoinvent): direct calculation not possible

Question

Hi,

When using a library for ecoinvent 3.11 the button "direct calculation" within a process tab is not shown: is it normal?

Why isn't it possible to make a direct calculation from a process when using a project linked to a library?

Will it be added in next updates?

Nicolas

Answer 1

Hello,

Yes, it is normal not to see a direct calculation within a process tab when using a library. To perform calculations, you need to build a product system from the process and then run the calculation from there. This workflow is typically faster than performing a direct calculation in a standard database.

There is no direct calculation button because libraries are based on pre-calculated matrices, which is what gives them their speed advantage. A direct calculation in a normal/standard DB would rebuild supply-chain connections and rerun calculations that are already embedded in the library DB type.

I recommend reading more about this here:

https://greendelta.github.io/openLCA2-manual/libraries/file_system.html

Comments

Hello,

Thank you for the answser and thank you for the recent development.
I understand it is not possible because of the pre-calculated matrices.

A comment:
Modelling in LCA is iterative I am always removing/adding inputs/outputs.
Using a product system for calculation is time costing because I can't remove easily any connection in any processes connected.
Removing the connection via the tab graphical showing is not easy with big LCA model and modifying a process after deleting product system then creating it again is time consuming.

==> Using the libraries will therefore not be feasible for me for now but I'll keep an eye on it.

Nicolas