A quick question to further understand INPUT and SHARE-IN

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Hi,


I’m a bit confused about the practical differences between the two approaches, even though I understand their setups:

1. Setting the INPUT (UP) constraint for auxiliary energy inputs for specific processes as the table shown below;
   


2. Using SHARE-IN for each energy type (with the same values as in INPUT), given the sum of SHARE-IN can exceed 1 when lim_type=UP
   . And we set EFF=1.Could you help clarify how their effects differ, especially when I introduce higher cost penalties or carbon taxes on fossil fuel sources?

Best,
Xiao

[Antti-L]

> Using SHARE-IN for each energy type (with the same values as in INPUT), given the sum of SHARE-IN can exceed 1 when lim_type=UP. And we set EFF=1. Could you help clarify how their effects differ, especially when I introduce higher cost penalties or carbon taxes on fossil fuel sources?

I think the main effect is that using SHARE-IN for each energy commodity with the same values as for INPUT would not make sense. SHARE-IN defines a genuine share in the total inputs of the same type (NRG), and therefore the maximum achievable share is 1.  Using EFF=1 would force the total energy input equal to the activity (i.e. the total energy input would be 1.0 per unit of activity), while in reality, for example in AT the total energy input should be 7.70 per unit of activity (based on the sum of the energy INPUTs). As you see, the effects would differ in a good way with respect to high carbon taxes, but would not be at all realistic. A possible small step closer to reality would be to define EFF=1/7.7 for AT.

Note also that INPUT implicitly creates the topology here (in the JRC-EU-TIMES). If you would just replace INPUT with SHARE-IN, you would actually have no inputs at all, unless you would explicitly define the topology.