Hello, could you help me model negative LULUCF emissions? I have defined process SINKLULUCF, which consumes SNKLUL as ENV commodity and I have given positive activity bounds for the output. Then I attached CGHG as the ENV_ACT to SNKLUL with a negative sign. I want it to be exact ame magnitude as SNKLUL but with a negative sign. Where am I making a mistake? should SNKLUL be defined as material instead? does negative sign mess up emission generally?
with my current modelling, I get SNKLUL and CGHG same amount with positive sign both. both snklul and CGHG are ENV and activity unit is kt
31-10-2025, 05:10 PM (This post was last modified: 31-10-2025, 05:11 PM by Antti-L.)
As far as I know, ENV_ACT does not accept any user-specified source group, it will be always defined with ACT as the source. Therefore, your ENV_ACT would not be working as intended; use FLO_EMIS instead.
As to how your SNKLUL and CGHG both have same amount with positive sign, I am not able to see why that is the case without seeing the model. Do you see the ENV_ACT correctly translated into FLO_EMIS in the browser?
>I have defined process SINKLULUCF, which consumes SNKLUL as ENV commodity and I have given positive activity bounds for the output.
In the picture, I am seeing SNKLUL as an output of SINKLULUCF, so it seems to be producing (not consuming) SNKLUL?
(31-10-2025, 05:10 PM)Antti-L Wrote: As far as I know, ENV_ACT does not accept any user-specified source group, it will be always defined with ACT as the source. Therefore, your ENV_ACT would not be working as intended; use FLO_EMIS instead.
As to how your SNKLUL and CGHG both have same amount with positive sign, I am not able to see why that is the case without seeing the model. Do you see the ENV_ACT correctly translated into FLO_EMIS in the browser?
>I have defined process SINKLULUCF, which consumes SNKLUL as ENV commodity and I have given positive activity bounds for the output.
In the picture, I am seeing SNKLUL as an output of SINKLULUCF, so it seems to be producing (not consuming) SNKLUL?
Sorry, yes, SNKLUL is output. Yes I can see FLO_EMIS in the items detail. So this is my current results attached. Everything seems to work after I changed SNKLUL to MAT instead of ENV. Does that make sense?
>Everything seems to work after I changed SNKLUL to MAT instead of ENV. Does that make sense?
No, it doesn't really make sense to me (without seeing the model), with respect to TIMES at least.
I guess VEDA might be doing some additional tricks here. Note that MAT is usually not preferred for emissions commodities, because it defines the commodity balance with FX type. But in this case it might be fine, due to the nature of SNKLUL.
It surely does work in TIMES! So I think VEDA must be doing something here "behind the scenes". But I think you should not worry about it now, because I think MAT and FX may be just fine for the SNKLUL in your model. Anyway, please bear in mind that the Other_indexes for that ENV_ACT does not work: The source will be the activity (ACT), but in your case the activity just happens to be equal to the SNKLUL output flow.
(31-10-2025, 06:22 PM)Antti-L Wrote: >ENV does not work for sure
It surely does work in TIMES! So I think VEDA must be doing something here "behind the scenes". But I think you should not worry about it now, because I think MAT and FX may be just fine for the SNKLUL in your model. Anyway, please bear in mind that the Other_indexes for that ENV_ACT does not work: The source will be the activity (ACT), but in your case the activity just happens to be equal to the SNKLUL output flow.
Well, at least in my situation ENV did not work, it kept producing positive numbers for both SNKLUL and CGHG in the same setup (everything else the same as current version). I also had tried FLO_EMIS instead of ENV_ACT before, it had the same problem. The problem got solved only after I changed ENV to MAT for SNKLUL
So I think VEDA must be doing something here "behind the scenes". But I think you should not worry about it now, because I think MAT and FX may be just fine for the SNKLUL in your model. Anyway, please bear in mind that the