TIAM - GHG constraint

[LucasD]

Thank you very much, it worked fine for me too.

[srchlela]

Dear Antti,
I hope you are doing well.

I am currently using the discussed constraint for the different regions and time frame (i.e GHG or TOTCO2 zero depending on regions). 
I aggregate the EEU and WEU regions as per attachment.
In the results the COMNET for GHG for WEU remains positive (the sum EEU+WEU as well) but works well for other regions with net GHG zero.

I was also using a growth constraint to limit the TOTCO2 growth starting 2080 for all regions. Please find it attached.
When I use it alongside this GHG constraint, other regions like Canada and Australia emit GHG in the end of the century (after being zero).

Please can you advice what I could enhance or do.

Thanks a lot,
Sophie

[Antti-L]

Recall once again the balances:

  VAR_COMNET − Imports + Exports  =  Production − Consumption

Hence, 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).

> In the results the COMNET for GHG for WEU remains positive (the sum EEU+WEU as well)

If you bound the net emissions of EEU+WEU to zero, then VAR_COMNET for (EEU+WEU) can be positive, if there are net imports of those emissions into EEU+WEU.  So, can you confirm that you indeed have net imports of GHG to EEU+WEU, when VAR_COMNET for GHG in (EEU+WEU) remains positive?  Anyway, you should see that the following holds:

  VAR_COMNET(t) − Imports(t) + Exports(t) ≤ 0  (for t ≥ 2050)

And that would mean the net GHG emissions in (EEU+WEU) are zero (or below).

> other regions like Canada and Australia emit GHG in the end of the century

I don't see how that could be possible, if you have constrained the net emissions (VAR_COMNET(t) − Imports(t) + Exports(t)) to zero?  Are you sure about that?  Could you show your GHG constraint for e.g. Canada, and the corresponding results for Canada (VAR_COMNET, Imports(t) and Exports(t))?

[srchlela]

Recall once again the balances:

  VAR_COMNET − Imports + Exports  =  Production − Consumption

Hence, 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).

> In the results the COMNET for GHG for WEU remains positive (the sum EEU+WEU as well)

If you bound the net emissions of EEU+WEU to zero, then VAR_COMNET for (EEU+WEU) can be positive, if there are net imports of those emissions into EEU+WEU.  So, can you confirm that you indeed have net imports of GHG to EEU+WEU, when VAR_COMNET for GHG in (EEU+WEU) remains positive?  Anyway, you should see that the following holds:

  VAR_COMNET(t) − Imports(t) + Exports(t) ≤ 0  (for t ≥ 2050)

And that would mean the net GHG emissions in (EEU+WEU) are zero (or below).

> other regions like Canada and Australia emit GHG in the end of the century

I don't see how that could be possible, if you have constrained the net emissions (VAR_COMNET(t) − Imports(t) + Exports(t)) to zero?  Are you sure about that?  Could you show your GHG constraint for e.g. Canada, and the corresponding results for Canada (VAR_COMNET, Imports(t) and Exports(t))?

Dear Antti, 

Thank you for your reply. This is the constraint for Canada and the results obtained. 

best, 
Sophie

[Antti-L]

Thanks.  Assuming that the row "GHG" means VAR_COMNET(CAN, t, GHG), your results for Canada indeed confirm that your net GHG emissions are zero in Canada from 2050 onwards, just as expected. 

So, is it all clear now?