User cosnstrain on aggregated commodity (emission)

[Lukas]

Hello,
the GHG is aggregated commodity from all GHG gases in the model.
I have an upper user constraint on GHG, called GHGnetZero2050. The attribute in the constraint is UC_COMNET. I found that the UC_RHSTS value in 2050 works rather as FX LimTipe. If I set this value to 33000, the result is 3300, although, without the GHGnetZero2050 constraint, the GHG is much lover.
Do I have the specification of the User constraint incorrect or what could cause such results?
Many thanks.

[Antti-L]

To me the constraint looks correct as such (although I would remove the Top_Check, which is meaningless). However, I am not seeing your T controls (T_S/T_E): make sure they are correct as well. I have been using similar constraints for bounding e.g. global GHG emissions for many many years, and they work well.

I am surprised if this is the first time you are modeling this kind of a GHG constraint summing over regions (i.e. you have never seen such working as expected)?  Or do you mean that such constraints have thus far worked, but now suddenly they don't?

Anyway, if your emissions are higher when using the constraint than when not using it, one explanation is that you might have free emission flows somewhere, which would be a modeling error.