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How to model a Utility Tariff based on Qualifying Demand Rate?

asked 2021-08-02 16:01:23 -0500

updated 2021-08-05 15:07:44 -0500


I was wondering if anyone could assist me with the following tariff question, where demand charge would not be qualified based on the maximum annual demand.

In other words, I modeling a utility tariff, where I have more than one kW threshold and consequently, using UtilityCost:Qualify- in order to select a proper range of tariffs for each category. However, the threshold value provided by the service company follows the third largest monthly demand (not the maximum annual)- as described below (for instance for 200 kW):

"The customer whose monthly Maximum Demand is expected to reach 200 kW or has reached 200 kW for any three months during the preceding 12 months is ineligible for service under this schedule."

I truly appreciate your support in advance.

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Could I say my situation falls into Field: Number of Months? In other words, if "3" applies here under Field: Number of Months? It doesn't seem it applies here. If we say 3, it means that Tariff Qualify is in effect only for 3 months- which is not the case!

@JasonGlazer Any ideas would be greatly appreciated!

Mohammad's avatar Mohammad  ( 2021-08-02 16:26:13 -0500 )edit

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answered 2021-08-03 09:04:32 -0500

Yes, the Number of Months field should be set to 3 and the Threshold Test field should be set to count:

    MaxDemand,               !- Utility Cost Qualify Name
    ExampleF,                !- Tariff Name
    TotalDemand,             !- Variable Name
    Maximum,                 !- Qualify Type
    200,                      !- Threshold Value or Variable Name
    Annual,                  !- Season
    Count,                   !- Threshold Test
    3;                       !- Number of Months

If the way the the qualification was phrased had been "three consecutive months" then the Threshold Test field should be set to Consecutive.

To learn more about how this works, see the InputOutputReference section on UtilityCost:Qualify.

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@JasonGlazer I truly appreciate all your continued support. Just to confirm, adding "3" for that field wouldn't force E+ to calculate my utility only for 3 months?

Thank you so much!

Mohammad's avatar Mohammad  ( 2021-08-03 09:50:14 -0500 )edit

The Number of Months is just used to only to indicate if the tariff is shown as Qualified in the Economics Results Summary Report where the total cost across qualified tariffs is shown.If you test it, you will see that the tariff is calculated if it is qualified or not. From the documentation "If the results of the simulation fall outside of the range of qualifications, that tariff is still calculated but the “Qualified” entry will say “No” and the UtilityCost:Qualify that caused its exclusion is shown."

JasonGlazer's avatar JasonGlazer  ( 2021-08-03 10:01:28 -0500 )edit

Further, if you know that a specific tariff is supposed to be used for the building and that is the only one (for that energy source) that you are using in an IDF file, you can omit the UtilityCost:Qualify completely.

JasonGlazer's avatar JasonGlazer  ( 2021-08-03 10:03:15 -0500 )edit

Thanks again for all the clarifications. The only thing that I found different is about the definitions of tariff by itself! Would you please confirm if the following statements means the same to you?

1- The tariff is only applicable for customers that use 200KW for at least three months of the year.

2- The customer whose monthly Maximum Demand is expected to reach 200KW or has reached 200KW for any three months during the preceding 12 months is ineligible for service under this schedule.


Mohammad's avatar Mohammad  ( 2021-08-03 15:54:39 -0500 )edit

They seem to be the opposite from one another, one says "only applicable" and the other says "ineligible."

JasonGlazer's avatar JasonGlazer  ( 2021-08-04 10:18:19 -0500 )edit

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Asked: 2021-08-02 16:01:23 -0500

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Last updated: Aug 05 '21