simulating technology economies of scale

[Antti-L]

Returning to your original question, as you mentioned that you are "still open to any other thoughts on these options", here are my brief comments (although your questions are not related to VEDA):

In general, I agree with Wouter that your options 1) – 3) are not possible in a model based on convex programming, such as an LP model. And therefore they are not possible in standard TIMES. However, you can model all of them by introducing binary variables and solving the model to a global optimum as a MIP model. In TIMES, the lumpy investment option can be utilized for introducing such binary variables. For option 2), TIMES v3.3.5 now also supports semi-continuous investment variables (but you will still in most cases need a MIP solver, because most solvers implement semi-continuous variables internally with binary variables, like Cplex).

[Poncelet88]

I'm trying to incorporate the lumpy investment option into my model as well and I seem to be doing something wrong as it is not working properly.

The SubRES file of my technologies looks as follows (in the actual file, some more attributes are specified (INVCOST, FIXOM, etc.):

TechName	TechDesc	Other_Indexes	Comm-IN-A	Comm-IN	Comm-OUT-A	Comm-OUT	START	NCAP_DISC	EFF~2010	EFF~2020	EFF~2030	EFF~2040	EFF~2050
\I:Technology Name	Technology Description		Auxiliary Input Commodity	Input Commodity	Auxiliary Output Commodity	Output Commodity	Starting Year		Efficiency
EPLT_COASubCSTNew_DSC	EPLT New Sub Critical Coal Steam Turbine			COA		ELC	2015		0.37	0.38	0.39		0.41
EPLT_COASuperCSTNew_DSC	EPLT New Super Critical Coal Steam Turbine			COA		ELC	2015		0.45	0.46	0.49		0.49
EPLT_COAIGCCNew_DSC	EPLT New Internal Gasification Combined Cycle Coal Plant			COA		ELC	2015		0.45	0.46	0.48		0.5
EPLT_GASOCGTNew_DSC	EPLT New Open Cycle Gas Turbine			GAS		ELC	2015		0.39	0.39	0.4		0.41
EPLT_GASOCGTAdvNew_DSC	EPLT New Advanced Open Cycle Gas Turbine			GAS		ELC	2015		0.42	0.45	0.45		0.45
EPLT_GASCCGTNew_DSC	EPLT New Combined Cycle Gas Turbine			GAS		ELC	2015		0.58	0.6	0.62		0.64
EPLT_NUCGenIIIplusNew_DSC	EPLT New Nuclear Plant of Gen III(+)			NUC		ELC	2015		1	1.00909091	1.021212121	1.03030303	1.039393939
		1						1
		2						1.5

 Furthermore, these processes are declared like this:

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
ELE	EPLT_COASuperCSTNew_DSC		EPLT New Super Critical Coal Steam Turbine	PJ	GW	DAYNITE		YES
ELE	EPLT_COASubCSTNew_DSC		EPLT New Sub Critical Coal Steam Turbine	PJ	GW	DAYNITE		YES
ELE	EPLT_COAIGCCNew_DSC		EPLT New Internal Gasification Combined Cycle Coal Plant	PJ	GW	DAYNITE		YES
ELE	EPLT_GASOCGTNew_DSC		EPLT New Open Cycle Gas Turbine	PJ	GW	DAYNITE		YES
ELE	EPLT_GASOCGTAdvNew_DSC		EPLT New Advanced Open Cycle Gas Turbine	PJ	GW	DAYNITE		YES
ELE	EPLT_GASCCGTNew_DSC		EPLT New Combined Cycle Gas Turbine	PJ	GW	DAYNITE		YES
ELE,DSCINV	EPLT_NUCGenIIIplusNew_DSC		EPLT New Nuclear Plant of Gen III(+)	PJ	GW	DAYNITE		YES

The model worked fine when I did not introduce the DSC option to the nuclear plants, but when I run it like this, it starts giving very strange results (producing with the IGCC plants without having capacity of this type of plants).

The only thing I did was adding the 'Other_Indexes' and 'NCAP_DISC' columns, entering an additional set for the nuclear technology (DSCINV) and putting on the discrete investment option in the case manager.

I can see the values I entered for the NCAP_DISC attribute in the TIMES view (although only aggregated over all 'units', but this is also the case in the example Antti provided).

When I run the original SubRES file but put on the Discrete Investment Option in the case manager, everything still works fine, so it seems to be related to the data in this file...

Anybody an idea about what I'm doing wrong here?

Also, is it necessary to fill in the Gams Options OPTCR and OPTCA in the options file in the case manager?

[Antti-L]

As far as I can see, you have only defined the topology and efficiencies for these technologies. I cannot see any investment costs, capacity bounds, or user constraints referring to capacities.

That would  well explain "producing with the IGCC plants without having capacity of this type of plants". Processes have a capacity only when there is a need for a capacity variable. Your processes don't seem to be needing any capacity, because the cost of capacity is zero, and you could thus have an infinite capacity without affecting the value of the objective  function.

The defaults for OPTCR and OPTCA are 0.1 and 0, and it is up to you whether you want to use different values. With these defaults you can be sure the integer solution is at most 10% off the optimum.

[EDIT:] Out of curiosity, I just tested your Subres data with the DEMO model, but adding also some investments costs, and an interpolation option for NCAP_DISC. On the basis of a quick look at the results, it worked well: The results showed investments into both the IGCC plants and into the NUCGenIIIplus plants. The IGCC plants were, of course, producing only within the limits of their capacity, and the NUCGenIIIplus plants capacity additions were discrete, just like modeled.

[Poncelet88]

Sorry Antti, my question was not that clear.

I have defined investment costs and other parameters for all technologies. I did not show the entire tabel before to limit the size of the table I was posting as that information did not seem relevant to me.

So here is how the entire table looks like:

TechName	TechDesc	Other_Indexes	Comm-IN-A	Comm-IN	Comm-OUT-A	Comm-OUT	START	NCAP_DISC	EFF~2010	EFF~2020	EFF~2030	EFF~2040	EFF~2050	STG_EFF	AFA	Life	CAP2ACT	INVCOST~2010	INVCOST~2020	INVCOST~2030	INVCOST~2040	INVCOST~2050	FIXOM~2010	FIXOM~2020	FIXOM~2030	FIXOM~2050	VAROM	NCAP_ELIFE	NCAP_ILED
\I:Technology Name	Technology Description		Auxiliary Input Commodity	Input Commodity	Auxiliary Output Commodity	Output Commodity	Starting Year		Efficiency					Storage Cyclic efficiency	Annual Availability Factor	Lifetime of Process	Capacity to Activity Factor	Investment Cost [€/kwe]					Fixed O&M Cost [€/kWa]				Variable O&M Cost [M€/PJ]
EPLT_COASubCSTNew_DSC	EPLT New Sub Critical Coal Steam Turbine			COA		ELC	2015		0.37	0.38	0.39		0.41		0.85	35	31.4496	1365	1365	1365		1365	27	27	27	27	2.152778		4
EPLT_COASuperCSTNew_DSC	EPLT New Super Critical Coal Steam Turbine			COA		ELC	2015		0.45	0.46	0.49		0.49		0.85	35	31.4496	1705	1700	1700		1700	34	34	34	33	1.666667		4
EPLT_COAIGCCNew_DSC	EPLT New Internal Gasification Combined Cycle Coal Plant			COA		ELC	2015		0.45	0.46	0.48		0.5		0.85	30	31.4496	2758	2489	2247		1830	55	50	45	37	2.083333		4
EPLT_GASOCGTNew_DSC	EPLT New Open Cycle Gas Turbine			GAS		ELC	2015		0.39	0.39	0.4		0.41		0.85	15	31.4496	486	486	476		472	12	12	12	12	1.111111		2
EPLT_GASOCGTAdvNew_DSC	EPLT New Advanced Open Cycle Gas Turbine			GAS		ELC	2015		0.42	0.45	0.45		0.45		0.85	15	31.4496	568	568	568		568	17	17	17	17	1.111111		2
EPLT_GASCCGTNew_DSC	EPLT New Combined Cycle Gas Turbine			GAS		ELC	2015		0.58	0.6	0.62		0.64		0.85	25	31.4496	855	855	855		855	26	21	20	20	1.388889		2
EPLT_NUCGenIIIplusNew_DSC	EPLT New Nuclear Plant of Gen III(+)			NUC		ELC	2015		1	1.00909091	1.021212121	1.03030303	1.039393939		0.85	60	31.4496	3660.44	3660.44	3660.44	3660.44	3660.44					3.083333		7
		1						1
		2						1.5

When I run the model without the information related to the discrete investments (so no 'other indexes' and NCAP_DISC columns), it works fine. When I use these 2 columns, the model no longer works fine.

As stated before, it delivers its demand for electricity by using the 'historical plants' (defined in BYT via stock) and IGCC. The strange thing is that it produces with the IGCC, although there is no investments in (new) capacity of IGCC.

I still can't figure out what is going wrong here...

[Antti-L]

Well, as basically the same data works just fine with the DEMO model, you should understand that it is rather hard to help you out with the problem. In particular, I am baffled about you reporting that the IGCC plant is  producing without  capacity, even though you have capacity costs for it!

Why don't you try and reproduce your problems with the DEMO model, and then upload it here? I could easily see what is going on if I had the model...

[Poncelet88]

It is working properly now. I still do not fully understand what was going wrong.

However, after it was working properly some strange things still occured.

It seems that some of the problems I had were related the way I used SubRES files to specify the technologies either as regular non-discrete technologies (via one SubRES file) or as discrete technologies in another SubRES file. The technologies had the same names. The goal was that I could turn on/off the Discrete Investment Option by selecting the proper SubRES file in the case manager. When I did this, I got some bizar results (in cases of discrete investment option 'turned on or off'). I decided to split up the model into two seperate models (one with discrete investments implemented and one without). This seems to help, though I do not know what the problem would be in the way I used the SubRES file.

A second thing that was decisive for getting everything to work normal was rebooting my PC

A final thing I noticed was that, when I had entered the data for NCAP_DISC, turning off the discrete investment option in the control panel diddn't actually turn off the discrete investments (although I did not check this anymore now that everything is working).

As the models are working properly now, and I'm not sure about the causes of the difficulties, I'm a bit reluctant on testing some more to find out the root of the problems. Anyhow, thanks for the support Antti! If you would still like to take a look at the model I'm using, let me know and I'll upload it.