Defining dynamic endogenous emission factor for output commodity based on input

[Simon Andersen]

Hi All, 

I'm trying to define a dynamic endogenous emission factor for an output commodity based on the emission factors of the input commodities.

In simple terms, I'm mixing two input commodities or fuels into one output commodity, through a Fuel-Transformation technology. This output commodity/fuel can be used later, and should emit when used. Each of the input commodities have a known emission factor - which is constant - however, I want the output commodity's emission factor to be dependent on the mixture of these two input commodities emission factor. 

To describe it in a more realistic context - take for example a gas network, which contains a blended gas composed of both a natural gas, which is emitting e.g. 57 kt CO2/PJ, and a biogas, emitting 0 kt CO2/PJ. The mixture of these creates the blended gas from the gasnet, and using this gas would emit the weighted average of this mixture (e.g. 50/50 mixture would lead to an emission factor of 28.5 kt CO2/PJ when using the blended gas).

Knowing the mixture before hand I want to be able "move" the emission factors from the two inputs over on the output commodity, so that when this is mixture changes over time (or is endogounsly defined) the emission factor for the output commodity changes with it. 

I have looked into the VEDA forum and found a discussion with Antii, where he uses the FLO_FUNCX attribute, however, on a case related specifically to a process' age. It seems that FLO_FUNC and FLO_SUM could perhaps be used to define this. I'm, however, unsure on how to define it in the manner that I'm describing. 
(https://forum.kanors-emr.org/showthread.php?tid=927&highlight=dynamic+emission+factor)

Is this at all possible? Or should it be handle afterwards from the outputs of the model - where the emission takes place in the blending of the commodities (emitting when used in the FT-technology)?

Thank you all in advance. 

BR.
Simon

[olexandr]

Hej Simon,

I'd say, one cannot do it that way, because one would introduce non-linearity when trying to compute the emission factor of the blended fuel, since the input shares are not fixed.

I was thinking how to do it in TIM, specifically to represent blending in a gas network. The best I could think of was to use 1 as emission factor for the output fuel, so that I could later multiply the sum of those emissions by the emissions factor calculated from the results.

Cheers,
Olex

[Simon Andersen]

Hej Olex,

Thank you for your reply. So, you would say that it is possible to create this endogenously defined emission factor - if I fix my input shares in the FT-technology. Because I was also thinking of using it for fuel-blending in the transport sector.

If that is so, how would you approach such a problem?

/Simon

[olexandr]

Well, I guess, if the shares are fixed, then the emissions factor of the output fuel is known and can just be assigned to it, can it not? :-)

[Simon Andersen]

Haha, yes I suppose so! Thank you anyways