Storage processes in peaking constraints
In the TIMES model generator, storage flows have never been taken into account in the peaking constraints, even if peaking constraints are defined for the stored commodity. Only the storage capacity is taken into account, in the same way as power plant capacities.

This may not be fully satisfactory for several reasons:

1. In TIMES, the capacity of a DAYNITE level timeslice storage represents the daily storage capacity. For example, if there is a winter season timeslice (W) corresponding to 20% of the whole year, and the winter peak timeslice (WD) is half of that (10%), and the storage capacity is 1 PJ, the maximum amount that could be discharged from the storage in the winter peak timeslice would be 1*365*0.2 = 73 PJ (assuming PRC_CAPACT=1, NCAP_AF=1, and no storage losses). However, in the peaking equation the contribution of the capacity to the peak supply is assumed to be  1*G_YRFR(WD)*NCAP_PKCNT, which amounts to 0.1 PJ if NCAP_PKCNT has the default value 1 (ignoring the peak reserve margin for simplicity). Therefore, the user should always remember to define an appropriate NCAP_PKCNT multiplier for a storage process producing a peaking commodity. In this case NCAP_PKCNT should be set to 730 if the full storage capacity would be assumed to be available in the peak timeslice!

2. Instead of the storage capacity, the user might want to use in the peaking equation the actual net output from the storage during the peak timeslice, because for various reasons it might not be possible that the full storage capacity is discharged at the peak time.

3. A storage process could, in principle, also have the peaking commodity as an input, but some other commodity as an output. In such a case the input flow into the storage, which might occur also during the peak timeslice, should perhaps be included on the consumption side of the peaking equation.

I would like to get some opinions about these issues. Should they be addressed in the code, and if so, how?

Antti (Current maintainer of the TIMES code)


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Storage processes in peaking constraints - by Antti-L - 23-06-2010, 12:29 PM

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