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UC Scenarios and Storage

Antti, Thanks for a quick feedback.

we have defined both type of stg technologies, TSS and IPSS.  I am not interested to have the latter, but without which I am getting infeasibility.  I suspect, it was due to lower bound on pumped hydro, input to which is fed from the two storage technologies.  But initial storage is not defined in the modelled (which I must do now).  Thus I added the small capacity of IPSS and the model solves.  But the IPSS keep on generating some output and activity, but no input.  from yr feedback, now I guess, the IPSS tech simply assume an inital storage and keep on generate commodity outputs! 

The fact is that, if I switched off the IPSS, even the TSS is not taking up.  model chose dummy import to fulfil the pumped hydro ACT bound.  I should have defined an initial storage (STG_CHRG ) for TSS!  let me try now.  Sorry, what is BoH?

Since it is a hourly model, I am keen to use the weekend solar PV outputs for pumping.  but it not happening, even if I adjusted the cost to pick up this stg tech

one more thing, I forgot to mention.  The TSS storage technology operates above its specified capacity limit at the timeslice level (i.e., the model stores and discharges a large quantity of electricity in a short period of time in excess of the available capacity) but the annual activity is within the annual capacity limit (CAP2ACT).   To address these issues, an additional grid technology is introduced before the storage technology.
Kannan Wrote:
one more thing, I forgot to mention.  The TSS storage technology operates above its specified capacity limit at the timeslice level (i.e., the model stores and discharges a large quantity of electricity in a short period of time in excess of the available capacity)

That should not possible. No storage process can ever store anything in excess of the available capacity (unless there is a bug in the TIMES code).  Maybe you could give some more information: What is the capacity and what is the activity, and what are the timeslice fractions in your model? Remember that the capacity of a DAYNITE storage process represents the daily storage capacity, and so the activity can well be many times larger than the capacity, depending on the number of days in the corresponding parent timeslice.

I’ll dig this case from our model archives and let you update.


I’ve tried TSS with STG_CHRG and deleted the IPSS.  But now the model chooses dummy to produced pumped hydro generation.

I’m attaching the storage part of our RES for yr info.


For pumped hydro, the base year generation is known and a act bd is implemented.  But I’m struggling to get it work. 

Of course, the other technologies are flexible to produce more ELC.  But the model uses dummy input for pumped hydo instad STGTSS.  Otherwise, it chooses STGIPSS tech!

Appreciate your help to sort-out this issues


Attached Files
.zip (Size: 12.38 KB / Downloads: 8)
I am not able to open the file; it is not recognized as a valid Zip file.
It seems that you are reporting several issues that might indicate a bug either in the model or in the TIMES code:
  1. Outputs form an IPS storage without inputs.
  2. Storage inventory that appears to be larger than the available capacity (TSS storage).
  3. Unclear problems with pumped hydro storage?
If you would like me to investigate these issues, it would be most efficient if you could provide me (by email) with the full set of the *.DD files and the *.RUN file for some scenario that reproduces the issues you are concerned with. Without seeing the full model specifications it is difficult to analyse the problems you have reported.

We would be grateful, if you could look at the referred issues.

The issue pertaining to the outputs in IPSS without any inputs could be that the model assumes some pre-storage (something like stockpiled) though not sure, how is it happening!

the capacity issues of TSS at 'timeslice' level, I’ll either go though my archives and find the database.  Else I’ll have to generate the same in our current version.

Still unclear, why the TSS is using dumpy input to fulfill the bound and then doesn’t use, despite residual capacity of pumped hydro, and cheap input commodity.

To start with, in the next couple of hours, I’ll regenerate the following two runs and send you the dd file.

1.Only having a TSS storage technology to show the use of dummy inputs

2. Including both TSS and IPSS to show the output from IPSS without input

Unfortunately I couldn’t upload any .xls file.  I've dumped the input files in a word and attached.  hope it's readable.


Attached Files
.doc   STEM-STG.doc (Size: 123 KB / Downloads: 6)
Thanks, Kannan, for providing the DD files and RUN file for my investigation.

Running and analysing the model revealed some crucial problems in the model specification, but also a couple of issues in the TIMES code. The problems in the model were the following:
  1. For the IPS storage, you have defined STG_LOSS = 1. This means that the annual storage losses are 100%, which is both meaningless for an inter-period storage, and also causes the storage flows to vanish from the storage equations. Consequently, the output flows became free due to the 100% annual losses. Proposed remedy: Either assume less than 100% storage losses for the IPS, or disable the storage completely. 100% losses per annum would mean that nothing could ever come out of the storage, and thus does not make sense.
  2. A second problem for the IPS storage is that you have assumed a different input and output commodity for the storage. However, an IPS storage can only have the same input and output commodity, which must also be the PG.
  3. For the TSS storage, the problem was also related to the different input and output commodities. TSS and NST storage processes can, indeed, have different input and output commodities, but in the case of TSS storage they must be both be included in the PG of the process. For accomplishing that, you should create a user-defined CG containing the input and output commodity, and set that group as the PG.
Hence, I was able to resolve the issues related to both the dummy imports and the free IPS output flows by the following changes: 1) By setting the IPS annual storage losses to 50% instead of 100%; 2) By re-defining the PG of the TSS storage to be a group containing the input and the output commodity.

On the basis of the investigation, the following fixes / improvements will be made into the TIMES code for the next TIMES release:
  1. The TIMES code will automatically disable any IPS storage with STG_LOSS 100%.
  2. The TIMES code will allow using NRG as the PG of a TSS storage, to make it easier to use different input and output commodities. That was supposed to work already, but now I can see that it does not work in the current version.
I am grateful that you brought up these issues, so that the TIMES code can be improved. If you have additional suggestions for improvements, please let us know.


Thanks a lot for looking at our model db.  It helped us a lot and now I have fixed the problem

I've to get rid off the IPSS storage because we found that the model choose to store electricity from a cheap period and use at a latter period when prices are high.  Of course this tradeoffs depends on the storage cost (& loss), future elc price escalations, discount rate, ...  In our case,  the model stores ELC to the max storage capacity and release after 3-4 ‘periods’.  Of course, the model finds it cost effective, as there is no storage cost.  However, pumped-water can be stored to a max of one yr or so.  I am wondering, whether we could somehow apply a constraint to IPSS storage technology so that stored-energy should be released in the next year (period)?  In other words, stored energy cannot be kept for two consecutive periods.


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