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Strange behavior Peaking Equation
#1
Hi,

I'm comparing different scenarios, which differ in the number of TS. Scenario TS1 has 12TS, and scenario TS2 has 288 TS. I have included a peaking equation, so that both scenarios (TS1 and TS2) would take into account the actual peak demand.

These are the peak demands in all scenarios [GW]

Real Peak  TS1 TS2
Demand 13.15842     11.35798      11.75629
COM_PKFLX     0.158518      0.119266

Therefore, I have introduced a value for COM_PKFLX value (see above) for the TS in which the peak occurs. Also, a 5% reserve margin is introduced. This is introduced via a scenario file (and a similar scenario file for scenario TS1):

~TFM_INS
TimeSlice LimType Attribute Year Attrib_Cond Val_Cond AllRegions BE Pset_Set Pset_PN Pset_PD Pset_CI Pset_CO Cset_Set Cset_CN Cset_CD
WIWeeh19 COM_PKFLX 0 3 ELC
WIWeeh19 COM_PKRSV 0 3 ELC
WIWeeh19 COM_PKFLX 2014 0.11926633 ELC
WIWeeh19 COM_PKRSV 2014 0.05 ELC


Now, when I look at the different scenarios (with and without the peaking equation), the behavior is quite strange:

Table Name: Capacity Comparison
Active Unit:
Period 2014 2014 2014 2014 2020 2020 2020 2020 2030 2030 2030 2030 2040 2040 2040 2040 2050 2050 2050 2050
Attribute Process\ScenarioDesc TS_1_no_RES TS_1_no_peak_no_RES TS_2_no_RES TS_2_no_peak_no_RES TS_1_no_RES TS_1_no_peak_no_RES TS_2_no_RES TS_2_no_peak_no_RES TS_1_no_RES TS_1_no_peak_no_RES TS_2_no_RES TS_2_no_peak_no_RES TS_1_no_RES TS_1_no_peak_no_RES TS_2_no_RES TS_2_no_peak_no_RES TS_1_no_RES TS_1_no_peak_no_RES TS_2_no_RES TS_2_no_peak_no_RES
VAR_Cap EPLT_COAST14 0.47 0.47 0.47 0.47 0.47 0.47 0.47 0.47
VAR_Cap EPLT_DSLICENew 1.367793495 3.055845704
VAR_Cap EPLT_GASCCGT14 9.0964 9.0964 9.0964 9.0964 7.27712 7.27712 7.27712 7.27712 4.244986667 4.244986667 4.244986667 4.244986667 1.212853333 1.212853333 1.212853333 1.212853333
VAR_Cap EPLT_GASGT14 0.28 0.28 0.28 0.28 0.224 0.224 0.224 0.224 0.130666667 0.130666667 0.130666667 0.130666667 0.037333333 0.037333333 0.037333333 0.037333333
VAR_Cap EPLT_NUC14 5.9258 5.9258 5.9258 5.9258 5.33322 5.33322 5.33322 5.33322 4.345586667 4.345586667 4.345586667 4.345586667 3.357953333 3.357953333 3.357953333 3.357953333 2.37032 2.37032 2.37032 2.37032
VAR_Cap EPLT_NUCGenIIIplusNew 2.49610002 2.49610002 2.504268193 2.504268193 8.03162693 8.03162693 8.04588541 8.04588541 10.75544797 10.75544797 10.7505638 10.7505638 13.17746867 13.17746867 13.17172884 13.17172884
VAR_Cap EPLT_PUMPST14 0.02031 0.02031 0.02031 0.02031 0.02031 0.02031 0.02031 0.02031 0.02031 0.02031 0.02031 0.02031 0.02031 0.02031 0.02031 0.02031 0.02031 0.02031 0.02031 0.02031
VAR_Cap EPLT_Ren_PVBuilding14 2.501 2.501 2.501 2.501 1.90076 1.90076 1.90076 1.90076 0.90036 0.90036 0.90036 0.90036
VAR_Cap EPLT_Ren_WTOffsh14 0.4902 0.4902 0.4902 0.4902 0.372552 0.372552 0.372552 0.372552 0.176472 0.176472 0.176472 0.176472
VAR_Cap EPLT_Ren_WTOnsh14 0.997 0.997 0.997 0.997 0.75772 0.75772 0.75772 0.75772 0.35892 0.35892 0.35892 0.35892
VAR_Cap Total 19.78071 19.78071 19.78071 19.78071 18.85178202 18.85178202 18.85995019 18.85995019 18.20892893 18.20892893 18.22318741 18.22318741 16.75169147 15.38389797 15.3790138 15.3790138 18.62394438 15.56809867 15.56235884 15.56235884


I have following remarks

1) The total installed capacity is the same for the first couple of periods (probably due to overcapacity existing in the first period(s)).

2) The introduction of the peaking equation seems to have no effect on scenario TS_2. I tested it, with a higher value of COM_PKFLX, and then, the effects can be seen.

3) The total installed capacity is higher in TS_1, then in TS_2 in the later periods, while both scenarios should in principle be exposed to the same peak. As can be seen in the period containing the year 2050, the same plants are installed for all scenarios (and used to provide the electricity demand). The only thing that differs is that in scenario TS_1 with peaking equation, there is some additional investments in the technology with the lowest investment cost (DSLICENew).

4) In the scenarios without peaking equation, I would expect that the installed capacity would be dimensioned to the peak demand, and therefore be somewhat higher in TS2, which is not the case (but this could be due to the pumped storage).

5) I have been experimenting with different values of COM_PKFLX. I checked scenarios without renewables (with low NCAP_PKCNT), and pumped storage plants, and I would expect in those cases that the total installed capacity in the scenario with the peaking equation to be (1+COM_PKFLX) times higher than the total installed capacity in scenarios without the peaking equation. However, this seems not to be the case (but I can't see a trend in the difference from the expected value).

So what concerns me, is that in scenario TS1, the installed capacity is considerably higher than for TS2, while they should be exposed to the same peak (peaking equation).
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#2

I cannot confirm your findings. In my tests, COM_PKFLX works just as expected. However, note that it is not the sum of the installed capacities that will be (1+COM_PKFLX) times higher when COM_PKFLX is used, but the total capacity contributing to the peak. So, if you have defined any NCAP_PKCNT values or PRC_CAPACT values that are not the same for all processes, you must take these into account if you want to verify the results.

And if no peaking equation is used, the total capacity will  of course reflect the demand at the peak timeslice, taking into account the availability factors (unless you have excess capacity due to past investments). However, if you can verify that in your model the total capacity is either higher or lower than what would actually be needed during the peak, as you seemed to suggest, I would certainly be interested to have a look at your model!

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