Dynamic constraint syntax

[Sebastien]

Hi everyone,

I am trying to build a dynamic constraint through VEDA templates but I am not really successful so far, and I have some questions about it:

1) In the DEMO model, the constraints Advanced_UC appear in the .lst file as dynamic constraints (EQE_UCRSUS), are they really dynamic? How to read them, then? I was thinking that the equation was like

but there is nothing dynamic here... Am I wrong? If not, why is it read as dynamic by the model, and why does it still work given that?

2°) I am also wondering about the (-1) coefficient on NCAP,INVSUB: is it always necessary to put it as negative, even with a variable on the RHS and the other on the LHS of the equation?

3°) What does SYNC mean, in UC_Attr? I tried to find a list of the indexes for UC_Attr, but I probably missed it...

4°) I would like to put a constraint forcing the production of a commodity down by a certain percentage each year. The mathematical formulation would be be something like

with the coefficient changing each year. I have so far written it like this

But it is seen as a static one (EQE_UCRTS) and as such, doesn't make sense at all... Also, I am not sure the T_SUC are correctly read. Could you help me here?

Thanks and regards!

Sebastien

[Antti-L]

Here are my quick answers;

1) Q: "Are they really dynamic?" A: Yes and no.  They are not dynamic in the "real sense". But all these three constraints require the use of features that are supported only by the dynamic constraint facility in TIMES.  See Sections 7.2 and 9.2 in the TIMES 3.1 Information Note http://www.iea-etsap.org/docs/TIMES-3.1-Information-Note.pdf.

2) Q: "I am also wondering about the (-1) coefficient on NCAP,INVSUB: is it always necessary to put it as negative?"  Investment Subsidies are, indeed, specified with positive numbers in the input parameter NCAP_ISUB.  But the idea in TIMES is that you can use any combination of NCAP_COST, NCAP_ITAX and NCAP_ISUB in the user constraints (possibly summing them together). Therefore, they must all be converted into "cost terms", i.e. subsidies need to be taken as negative values in the user constraints, to support possible summing up with other cost terms. Thus the -1 sign.

3) Q: "What does SYNC mean, in UC_Attr?" SYNC is briefly explained in the doc mentioned above. To be in sync with something” means “to coincide with something, and here SYNC makes the time periods on both sides coincide with each other. In other words, by using SYNC on the RHS side, you can make a dynamic constraint static, and you will then be able to use both sides for defining coefficients.

4) What are the numbers 3,4,5 in your T_SUC? You should specify the Milestone years there, for example 2010,2015,2020. Also, I think your COMPRD coefficients on the LHS and RHS sides should both be positive, no?  See some suggestions below (the second one does not require UC_TSUC):

[Sebastien]

Thank you very much Antti for this answer! I had missed indeed the information note, and the SYNC attribute really baffled me... For the numbers 3, 4, 5, I tried to list the periods by their numbers instead of milestone years, but this quite obviously didn't work... And I had designed a workaround using a growth constraint, but your solutions are definitely better!