How can I display 'mass balance' in openLCA?

Question

Dear openLCA support,

I would be interested in how I can create a representative mass balance in OpenLCA? At first I thought I have a 'mass balance' when I calculate the productsystem (e.g. for cork slab in ecoinvent) and then look at the inventory results but there I cant see the original inputs like electricity or outputs etc. There I see all the emissions.

If I select a given process from ecoinvent (e.g. slab cork) the input and output flows are specified, right? Sometimes there are more input flows than output flows before I calculate them. How can that be? The system always has to be balanced, right?

I would be very happy if you could help me.

With regards,

Nell Stankewitz

Answer 1

Hi Nell,

indeed, you can calculate the mass balance somewhat from both a single process (exporting inputs and outputs to excel e.g.) and also from the calculated inventory (again, copying and pasting to excel), but the balance will often not be perfect (e.g., due to omission of incineration air input, or cooling water input, or also since quite some products are not specified in mass but in pieces or volumes e.g.).

Theoretically, an LCA system has to be balanced, since you do not have any storage terms in an LCA model.

Best wishes,

Andreas