Output attribute - quick question

[Neha Jaggeshar]

Hello, 
I am modelling a process called AFORRWOOD_PROC, where raw roundwood (FORRWOOD_RAW) is converted into processed roundwood (ROUNDWOOD). 
Both commodities are defined as MAT. My intention is that 1 unit of raw roundwood should produce 0.88 units of processed roundwood. In my VEDA template, I have set Comm_IN = FORRWOOD_RAW with Input = 1.00 and Comm_OUT = ROUNDWOOD with Output = 0.88. However, when I check the data there is no VDA_FLO entry for ROUNDWOOD under AFORRWOOD_PROC.
As a result, TIMES treats the process as if there is a 1:1 conversion between inputs and outputs in both the input tables and the results.

Interestingly, if I change my approach and instead set the process so that Input = 1.136 and Output = 1.00, the model finally reflects the intended 0.88 ratio between raw and processed roundwood. 


I do know from the documentation that the commodity balance constraint for MAT commodities are generated as equality, but is that the reason behind this behaviour? 

Am I missing or misinterpreting any attributes in my template that could explain why my VDA_FLO = 0.88 entry is ignored? Any clarification much appreciated. 

Thank you, 
Neha 

[Antti-L]

It is indeed ignored both by VEDA, and it would be ignored by TIMES as well, if the Output commodity is in the PCG (primary group, which defines the activity).  As you should know, Output defines the level of an output flow in proportion to the activity. But if that output flow also defines the activity, any value <>1 would be, by definition, mathematically inconsistent.  So, your model would basically become infeasible if your Output=0.88 would not be ignored, because you would have (Activity = ROUNDWOOD) and (ROUNDWOOD = 0.88 × Activity). You did not show how you defined the PCG, but I assume your PCG=ROUNDWOOD?

You could use EFF= 0.88 instead of Input=1.136 (efficiency of producing ROUNDWOOD from FORRWOOD_RAW is 0.88). Or you could also use PRC_ACTFLO(ROUNDWOOD) = 0.88 together with Input = 1, but in that case your activity and capacity would no longer represent the product output (ROUNDWOOD).  But if the input may be assumed the activity, you could also just define PCG=FORRWOOD_RAW, and then all the Output parameters would work. In any case, make sure your PCG does not include the residue outputs.

[Neha Jaggeshar]

Hi Antti, 

Thank you for the clarification!  
You were right, my PCG = ROUNDWOOD. I've set PCG = FORRWOOD_RAW and that solved the problem. All three output flows are correctly reprsented in both the inputs and results table. 

Thanks again,

Neha.