Negative emissions

[LucasD]

Dear forum,

I want to make sure that the electricity sector of my global model can be carbon-negative, by running BECCS plants. In a first attempt, I created a CO2 sink whose inputs are the two following commodities:

• ELCCO2N [1kt], which represents the amount of CO2 emissions generated from the electricity sector
  


• CPTELCCO2B [1kt], which represents the amount of biogenic CO2 captured from BECCS plants
  

So the model has to capture biogenic CO2 in order to remove CO2 that has been generated from the electricity sector, in equal proportions. The thing is, I realized that the electricity sector is never carbon negative in the results, although it gets net zero. I suspect the current modeling simply does not allow the electricity sector to be carbon negative because the removal process actually requires the electricity sector to generate ELCCO2N.

So, my question is: how can I tell the model that it can run the CO2 sink even though ELCCO2N is not available? In other words, how can I tell the model that the ELCCO2N commodity can be negative?


Hope it's clear,

Lucas

[Antti-L]

I hope you can see the picture below, showing an example where the VAR_COMNET of the commodity BIOECO2 is defined to have a lower bound of -INF, in order to be able to have negative values for this variable.

[LucasD]

Simple! Thank you very much.