Problem with flex fuel techs

[lppnog]

Hello,

i came for help before regarding  constraints for flex fuel processes, but it looks like my flex fuel process itself is not working properly: it should either use one fuel or the other to produce the output commodity, but it uses both inputs simultaneously to do it, causing an overproduction of one of my fuels. I tried to use EFF and CEFF atributes, but none of those work.

Would anyone know how to model this correctly and/or which atribute to use?

Thanks.

[AKanudia]

Please post a screen shot of the VFE browse screen such that all the parameters specified for this process are visible (along with commodity/commgrp indexes)

[lppnog]

Is it the screenshot you are asking for?

Thank you very much.

[lppnog]

Here is the technology carachterization:

TechName	TechDesc	Comm-IN	Comm-OUT	START	INVCOST	EFF	CEFF	FIXOM~2009	VAROM	Life	CAP2ACT
\I:Technology Name	Technology Description	Input Commodity	Output Commodity	Starting Year		Efficiency	Commodity Efficiency	Fixed O&M Cost	Variable O&M Cost	Lifetime of Process	Capacity to Activity Factor
VEHICLE_ICE_FLEX_2010	New investment in internal combustion engine flex-fuel vehicles: 2010-2020.			2010	30000.0			0.348	0	15	1
		BLENDED_GASOLINE				10					1
		ETHANOL				14					1
			PASS_PRIV_TRANS								1
Sets	TechName	TechDesc	Tact	Tcap	Tslvl	PrimaryCG	Vintage
\I: Process Set Membership	Technology Name	Technology Description	Activity Unit	Capacity Unit	Timeslice Operational Level	Operational Commodity Group	Vintage Tracking
PRE	VEHICLE_ICE_FLEX_2010	New investment in internal combustion engine flex-fuel vehicles	MWyr	MW	ANNUAL		NO

[Antti-L]

From the table above it seems you are specifying EFF for both ETHANOL and BLENDED_GASOLINE. That will certainly not work: Only a single EFF can be defined for each process and period. If you want that the efficiency is 10 when using gasoline, and 14 when using ethanol, you can specify these two efficiencies with CEFF, provided that both commodities are of the same type (NRG). But if they are of different types, that will not work either, and then you should use FLO_EFF instead.

[lppnog]

Hi, thank you.

I have already tried  using CEFF (exactly the same structure above, the only difference was 10 and 14 were declared in CEFF column, not in EFF) as well, but the problem remains. Looks like it does not "see" this commodity efficiency and produces the output commodity using both ETHANOL and BLENDED_GASOLINE at levels much above than the efficiency would allow...

[Antti-L]

Ok, the source for the problem remains unknown. As Amit suggested, posting a screen shot of the VFE browse screen (Basic functions → Browse → TIMES View), such that all the parameters specified for this process are visible (along with commodity/commgrp indexes), might help diagnosing the problem.

You could also check the contents of the file QA_CHECK.LOG in the work folder under VEDA-FE (usually GAMS_WrkTIMES). Does that file contain any warnings related to the process or any of the commodities involved?