TIAM - GHG constraint

[srchlela]

Dear all, 

I have a UC_COMNET on the GHG commodity that sets it to zero in 2050 for the EEU+WEU (please see the attached). 
In the results, the Var_Fout for GHG goes to zero, whereas all the emissions commodities (the CO2, CH4, and N2O) do not.

They are agreggated as in the attached photo. 

Then I tried a UC_COMNET also for EU on the commodities. Some go to zero in the CO2 but non in CH4 or N2O. 

What could be the reason so that emission commodities do not follow GHG? or do you have any advice to better analyze the problem. 


Thanks a lot! 

Best,
Sophie

[Antti-L]

> I have a UC_COMNET on the GHG commodity that sets it to zero in 2050 for the EEU+WEU (please see the attached). In the results, the Var_Fout for GHG goes to zero, whereas all the emissions commodities (the CO2, CH4, and N2O) do not.

Not quite clear what is actually going on here. Your constraint bounds the sum of VAR_COMNET(GHG) over the two regions to zero in the years 2050–.  But then, you say "Var_Fout for GHG goes to zero, whereas all the emissions commodities (the CO2, CH4, and N2O) do not."  VAR_Fout and VAR_COMNET are different variables, and COM_AGG aggregates the VAR_COMNETs, not VAR_Fouts.

Anyway, to get a better picture, could you post a table showing the VAR_COMNET results for GHG, CO2, CH4 and N2O, as well as the Var_Fin & Var_Fout for GHG (all these for EEU+WEU)?

[srchlela]

> I have a UC_COMNET on the GHG commodity that sets it to zero in 2050 for the EEU+WEU (please see the attached). In the results, the Var_Fout for GHG goes to zero, whereas all the emissions commodities (the CO2, CH4, and N2O) do not.

Not quite clear what is actually going on here. Your constraint bounds the sum of VAR_COMNET(GHG) over the two regions to zero in the years 2050–.  But then, you say "Var_Fout for GHG goes to zero, whereas all the emissions commodities (the CO2, CH4, and N2O) do not."  VAR_Fout and VAR_COMNET are different variables, and COM_AGG aggregates the VAR_COMNETs, not VAR_Fouts.

Anyway, to get a better picture, could you post a table showing the VAR_COMNET results for GHG, CO2, CH4 and N2O, as well as the Var_Fin & Var_Fout for GHG (all these for EEU+WEU)?

Hello Antti,

Thank you very much ! Please find the results attached in an excel file.

P.S I also tried a UC_COMNET for the commodities (as per the attached image) for which you can find the results in "scenario" ending with "comm"

Best,
Sophie

[Antti-L]

Hmm... ok, I missed that you are also aggregating all the CH4 and N2O emissions via NONCO2, and not directly from TOTCH4 / TOTN2O.

In your results, you have positive VAR_COMNETs for TOTCH4 / TOTN2O, but I cannot see anything reported for NONCO2. I guess there is something wrong with that commodity.  Looks like it may not have any commodity balances active in the model at all. Can you either confirm, or perhaps show how this commodity has been defined?  Are you seeing any results for NONCO2?

[srchlela]

> I have a UC_COMNET on the GHG commodity that sets it to zero in 2050 for the EEU+WEU (please see the attached). In the results, the Var_Fout for GHG goes to zero, whereas all the emissions commodities (the CO2, CH4, and N2O) do not.

Not quite clear what is actually going on here. Your constraint bounds the sum of VAR_COMNET(GHG) over the two regions to zero in the years 2050–.  But then, you say "Var_Fout for GHG goes to zero, whereas all the emissions commodities (the CO2, CH4, and N2O) do not."  VAR_Fout and VAR_COMNET are different variables, and COM_AGG aggregates the VAR_COMNETs, not VAR_Fouts.

Anyway, to get a better picture, could you post a table showing the VAR_COMNET results for GHG, CO2, CH4 and N2O, as well as the Var_Fin & Var_Fout for GHG (all these for EEU+WEU)?

Hello Antti,

Thank you very much ! Please find the results attached in an excel file.

P.S I also tried a UC_COMNET for the commodities (as per the attached image) for which you can find the results in "scenario" ending with "comm"

Best,
Sophie

Yes i just didn't show it, my bad. I am attaching the results for the two scenarios. Please also find attached the aggregation for non-co2, Many thanks!

[Antti-L]

Ok thanks, that explains it.  Your VAR_COMNET results for NONCO2 are indeed zero from 2050 onwards.
And so, the constraint is working as expected: The total (net) GHG emssions are zero, both for TOTCO2 and for CH4 and N2O via NONCO2.

It of course remains unclear, which process(es) are consuming the NONCO2.  But for TOTCO2, I can see that the model is exporting emissions to the GBL region. It seems that your modeling of emissions is a bit unusual.  If these trade links are representing global emission trade, you cannot really bound the regional emissions by user constraints simply on VAR_COMNET, unless you first bound those trade flows to zero, to prevent reducing net regional emissions by trading.

I have myself mainly been modeling only with implicit emission trade, by using such bubble constraints, or allowance prices, without such global trade links. Hence, I have not been facing this kind of an issue...

Ahh... I can see now that these trade links were indeed by default defined in the original old TIAM, sorry.  I have been using a different version of TIAM, where such are not included.

[Antti-L]

If you don't want to disable those trade links, you can still of course bound the (true) regional net emissions by user constraints by adding any export flows of emissions and subtracting any import flows of emissions to the VAR_COMNET amounts, by adding these terms using UC_IRE.  Illustration below (could not test, it as I don't have the old TIAM under my VEDA):

     

[srchlela]

If you don't want to disable those trade links, you can still of course bound the (true) regional net emissions by user constraints by adding any export flows of emissions and subtracting any import flows of emissions to the VAR_COMNET amounts, by adding these terms using UC_IRE.  Illustration below (could not test, it as I don't have the old TIAM under my VEDA):

 

Dear Antti, 

Thank you for your explanation and solution, I am currently trying the suggested method. 

Best regards, 

Sophie

[LucasD]

Hello, I tried the constraint you suggested @Antti, and it seems like it does not work.

LI used the constraint formulated above in a screenshot to tell the model that China is carbon neutral in 2060 (TOTCO2=0). It runs okay but when I look at the Var_ComNet of TOTCO2 for China in the results, it is well above 0. As I am not having an infeasibility, it looks like the model respects the constraint though. Maybe I am not looking at the right things in the results. Note that, when GHG trades are turned off, China gets carbon-neutral. Do you have any idea of what's happening?

Thank you,
Lucas

[Antti-L]

The commodity balance for any commodity (including emissions) can be written in simplified terms as follows:

  Production + Imports  =  Consumption + Exports + VAR_COMNET

And this is equivalent to:

  VAR_COMNET − Imports + Exports  =  Production − Consumption

Therefore, if you make a constraint bounding  (VAR_COMNET − Imports + Exports) to zero, then (Production − Consumption) will also be bounded to zero, and that expression is the regional net emissions (unless you have dummy imports for the constraint).  And bounding  (VAR_COMNET − Imports + Exports) to the emission target was the constraint I suggested.  (I was not suggesting to bound just VAR_COMNET  to the target, e.g. zero).

Therefore, I cannot see why that would not be working.   Can you give some more information demonstrating that it does not work like described above?

[LucasD]

Please see attacheda table with different attributes of TOTCO2. The scenario "CCU_REF_High_GT" refers to the scenario where GHG trades are activated. The scenario below, that is when GHG trades are turned off, and we observe what we expect. Besides, even though GHG trades are activated, China does not trade any CO2.

There are no dummy imports.

TOTCO2 is the aggregation of many sectoral CO2. I just checked if the sum of the Var_FOut of the aggregated commodities equals the Var_FOut of TOTCO2.

Similar constraints are formulated for other regions of the model, and it's working fine.

[Antti-L]

I find the table unreadable here, does it look readable to you?  [Edit:] Ah... you just edited your post with a readable version...

> Besides, even though GHG trades are activated, China does not trade any CO2.

Ok, fine, but if that is so (no trades in any GHG emissions involved in the constraint), then it is basically impossible that the constraints I suggested wouldn't work.    That is because then they would then be bounding VAR_COMNET to zero. But you have actually not disclosed how your constraint(s) look like; and so I have no doubt that they might not be working as intended. And your table clearly shows that you are not bounding VAR_COMNET to zero, and so your constraints indeed seem different.

> Similar constraints are formulated for other regions of the model, and it's working fine.

Are you saying the the constraints I suggested work fine for other regions, but not China?

[LucasD]

I find the table unreadable here, does it look readable to you?  [Edit:] Ah... you just edited your post with a readable version...

> Besides, even though GHG trades are activated, China does not trade any CO2.

Ok, fine, but if that is so (no trades in any GHG emissions involved in the constraint), then it is basically impossible that the constraints I suggested wouldn't work.    That is because then they would then be bounding VAR_COMNET to zero. But you have actually not disclosed how your constraint(s) look like; and so I have no doubt that they might not be working as intended. And your table clearly shows that you are not bounding VAR_COMNET to zero, and so your constraints indeed seem different.

> Similar constraints are formulated for other regions of the model, and it's working fine.

Are you saying the the constraints I suggested work fine for other regions, but not China?

> then it is basically impossible that the constraints I suggested wouldn't work.

I agree with that but I cannot find the mistake. Please see attached the constraint.

> Are you saying the constraints I suggested work fine for other regions, but not China?

Other regions like India, Korea, etc. don't get NZ just like China, but others (USA, Canada, ...) do fine.

[Antti-L]

> Other regions like India, Korea, etc. don't get NZ just like China, but others (USA, Canada, ...) do fine.

Ok thanks, that sounds very strange. It has become clear that my capabilities are insufficient for resolving your problem without having a reproducible case.

However, if you wish, I can investigate it to the bottom of it, but only if you can provide me all the model input files (*.DD and *.RUN) plus the listing file *.LST, for the case "CCU_REF_High_GT", where you have defined these constraints, of which some seem to work and some don't. For providing the files, sending me a download link in a private message (via Dropbox, Google drive or equivalent) would be ok.

[Antti-L]

Ok, thanks I got your model files.

It turned out that there were indeed substantial trades in the non-CO2 GHG emissions involved in some of the regions (in those for which you were bounding only TOTCO2).  For example, in China the emissions remained at the level of 8.4 Gt(CO2) in 2060, because the net imports of NONCO2 were of that same amount.  In other words, the CO2 emission level in 2060 was completely explained by those net imports of NONCO2.

This is explained by you having deviated away from my formulation, which was based on the relation:

  VAR_COMNET − Imports + Exports  =  Production − Consumption

For four regions (CHI, IND, JPN, SKO), you are including only VAR_COMNET(TOTCO2) in the constraints, but you still subtracted the net imports in all GHG emissions, by including NONCO2. Consequently, that breaks the logic of those constraints, and they no longer worked as intended. If bounding only TOTCO2, you should of course include only the trade in TOTCO2 in the constraint, not in other emissions.

I tested by removing the NONCO2 trade terms from the UP_GHGMAX* constraints for those four regions, and then the results were as intended by the constraints, e.g. CHI having zero TOTCO2 in 2060.