Trade feature

[seungwoo.kang]

Hello,
 
I recently introduced new commodities’ international trade in TIAM model. However, I found out some interesting and unwanted results.
 
I enabled the exchange between A and B region as well as B and C region not allowing the exchange between A and C region.  However, even if C region can import from other regions D, E, F…etc., C imported from A passing through B region. And B region does only transfer of the commodity (even no production in B)
 
That is not what I wanted to introduce in the model.  Is there any solution to fix it, more specifically to prohibit transfer?
 
Thank you,
 
Seungwoo

[Antti-L]

Well, you could set a user constraint limiting imports/exports according to consumption/production:

   Imports-to-B ≤ a × Consumption-in-B
   Exports-from-B ≤ b × Production-in-B

where a ≤ 1, b ≤ 1.

They will not actually prohibit transfer (=simultaneous imports and exports to/from B), but will ensure that if any amount is imported into B, at least that amount will be consumed in B, and if any amount is exported, at least that amount will be produced in B.

As far as I can see, strictly prohibiting simultaneous imports and exports is not possible.

[seungwoo.kang]

Thank you for your comments!