E+ Tariff Measure Impacting Modeled Peak Electric Demand

I am attempting to evaluate several measures using the Parametric Analysis Tool. While setting up PAT I started by adding the "Tariff Selection Time and Date Dependent with Off Peak Demand Charge" to PAT only and comparing the results to the baseline. Stated differently, the tariff measure is the only measure I have added to my PAT file.

After simulating, the results show a 10% decrease in peak electric demand. I do not believe the tariff measure should impact energy use or demand, only the cost of energy. I've tried multiple configurations and each results in the 10% demand reduction. Any guidance would be greatly appreciated!

It appears that since I am new to Unmet Hours that I do not have enough points to upload files. If there is another way for me to share screenshots or files please let me know.

Phil Keuhn

asked 2017-01-18 14:50:57 -0500

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__AmirRoth__

updated 2017-08-20 15:01:05 -0500

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The only impact the tariff measure should have on non-cost simulation results is due to the timestep being changed to match a multiple of the tariff demand window length. Which specific measure are you using, and are you getting any info messages about the timestep changing?

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David Goldwasser

answered 2017-01-18 15:49:10 -0500

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David,

Thanks for your help! I spent a day trying to figure that out. I aligned the time steps and the discrepancy in PAT went away. To answer your question the specific measure I'm using is named "Tariff Selection Time and Date Dependent with Off Peak Demand Charge".

Thanks again, Phil

Phil Keuhn (2017-01-18 17:23:06 -0500) edit

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Old question, but I'd like to point out that there can be two peak demand profiles when the model has a tariff with time of use demand charges; (1) the builing's peak demand profile and (2) the utility's peak demand profile, which may or may not be coincident. See the chart below for an example comparing the "Facility" demand from the Electricity:Facility meter and the "Utility" demand from the Tariff Report in EnergyPlus.

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