How to constraint commodity flows among processes

[giulia realmonte]

You can of course define a constraint requiring that the ELCC output from solar and wind power plants is greater than or equal to the input of electricity into some process(es), e.g. AZDAC00*, if that's what you mean, i.e. something like this:

SUM({P | TOP(P,WIND,IN) or TOP(P,SOLAR,IN)} VAR_FLO(P,ELCC)) ≥ SUM({P ∈ AZDAC00*} VAR_FLO(P,ELCC))

And yes, you could also define a new commodity ELCC_RNW for electricity produced by solar and wind, and require that {P ∈ AZDAC00*} must consume that ELCC_RNW in amounts equal to consuming ELCC. But as such, I think it would accomplish the same thing, i.e. it would just constrain the amount of wind and solar electricity to be greater than or equal to the input to AZDAC00*, but maybe I am missing something?

Yes, I think that the first constraint could work for my case.
How can I implement it through a UC spreadsheet? I am more familiar with constraint on capacity than on commodity flows...

thanks again,
Giulia