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Electric demand costs based on daily peak kW values

asked 2018-10-18 15:59:15 -0500

gokul's avatar

updated 2018-10-18 16:00:31 -0500

I am trying to use a rates structure which calculates costs for energy and demand using daily kWh and daily peak kW values. I was able to create a UtilityCost:Tariff object, with a real time pricing schedule which references a Schedule:Compact object or a Schedule:File object.

From my understanding, this could potentially calculate the energy charges (based on kWh) based on the schedule charges. Is there a way to do the same based on daily peak kW? From reading the I/O reference in energyplus, it looks like I can't apply a rate structure based on the daily peak kW, as the UtilityCost:Tariff and all the different UtilityCost:Charge: objects are based on a monthly demand structure. Is this right? Or am i missing something? Additionally, any tips/tricks where I could make this work will also be appreciated! Thanks.

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answered 2018-10-19 07:59:25 -0500

updated 2018-10-19 08:00:11 -0500

EnergyPlus does not have a way to compute utility costs based on daily peak demand. It does have a Demand WIndow Length in the UtilityCost:Tariff object but that reports the day of the month that has the highest usage not what you are describing. A utility tariff that calculates the charges on a daily basis for the peak kW each day seems very unusual. The first thing I would do is review the tariff from the utility very carefully and verify that is really what is being described.

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Thank you for the answer! I did check the rate structure again, and it is indeed peak kW per day!! The utility rate in question is the Colorado Springs utility rates for commercial buildings, and I assume it's been this way for a while. Also, I'm curious, are you aware of other modeling engines which can do this?

gokul's avatar gokul  ( 2018-10-19 10:22:46 -0500 )edit

Thanks for sending me the link to the tariff. I'm not aware of any other modeling engine that can do this. Probably the best approach with EnergyPlus is to just make a spreadsheet using the facility electricity meter (Facility Total Purchased Electric Power). The Output:Variable object does allow aggregation on a daily basis. I would double check it is showing the values you expect. Then make a spreadsheet that calculates that value each day. I posted a new issue on this.

JasonGlazer's avatar JasonGlazer  ( 2018-10-19 10:42:40 -0500 )edit

Thanks again for filing the new-feature request! And nice idea!! I'll use the Output:Variable and postprocess the results with my rates structure.

gokul's avatar gokul  ( 2018-10-19 11:08:49 -0500 )edit

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Asked: 2018-10-18 15:59:15 -0500

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Last updated: Oct 19 '18