COMMODITY CONSTRAINTS

[Tanzeel]

  OILGSL.docx (Size: 320.34 KB / Downloads: 8) I tried the following constraint to bound the flow of imported gasoline. Having a very little knowledge of UC's, I want to verify it. It seems that constraint is somehow working but did not obey the rule, in this case "LO". IT MIGHT BE the HIGHER PRICE OF IMPORT (ASSUMED) because local refinery production is enhanced in following years.

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[Antti-L]

If you want to bound the flow of gasoline imported via IMPOILGSL, the best way is to use FLO_BND (or ACT_BND).
Did you consider using these attributes?

Using UC_COMNET as in your example does not bound the flow of gasoline imported via IMPOILGSL.  The constraint would bound the net (=excess) production of gasoline to 150, such that the total supply of gasoline would be 150 larger than the demand.

[Tanzeel]

If you want to bound the flow of gasoline imported via IMPOILGSL, the best way is to use FLO_BND (or ACT_BND).
Did you consider using these attributes?

Using UC_COMNET as in your example does not bound the flow of gasoline imported via IMPOILGSL.  The constraint would bound the net (=excess) production of gasoline to 150, such that the total supply of gasoline would be 150 larger than the demand.

Thanks Antti-L. After some minor changes, the model now shows the expected result. I changed the constraint with ACT but this constraint is not working with FLO attribute as I am more comfortable with it.

[Antti-L]

Yes, using UC_ACT certainly works, and so would of course UC_IRE, which must be used for trade processes instead of UC_FLO. 
UC_FLO does not work for trade processes, because they do not have any VAR_FLO variables. 

But as I mentioned above, the bounds are much easier to define by using FLO_BND (or ACT_BND):


The FLO_BND parameters above would accomplish the same lower bound of 120 for IMPOILGSL as your UC constraint.