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Modeling On-peak Demand

  • randy
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03 Nov 2017 13:23 #5710 by randy
Replied by randy on topic Modeling On-peak Demand
Here's a variation on kerber's question... I have similarly structured demand rates. Only the time-of-use (TOU) element is seasonal, not hourly. I have a $3/kW distrib/delivery charge and an additional $11/kW (winter) or $14/kW (summer) demand charge.
Now, I believe I could enter these values two different ways:
1) $3/kW every month in the "by month" section, then $11/kW & $14/kW respectively in the "by TOU" section
2) Or, transpose these values. $11 & $14 in "by month," then $3/kW in "by TOU"

However, changing absolutely nothing else in the model, parametric simulation generates completely different NPV results.
What am I missing?
Randy

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  • pgilman
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07 Nov 2017 16:40 #5711 by pgilman
Replied by pgilman on topic Modeling On-peak Demand
Dear Randy,

I think Method 1 is the way to model that demand rate structure. That will result in two demand charges per month: One calculated as $3/kW * peak usage per month for every month of the year, and one calculated as either $11/kW * peak usage per month or $14/kW * peak usage per month depending on the season.

I'm not sure I understand the parametric simulation you ran. I would expect Method 1 and Method 2 to give different NPV results.

Best regards,
Paul.

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  • randy
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07 Nov 2017 21:55 #5712 by randy
Replied by randy on topic Modeling On-peak Demand
Thanks Paul,
Shouldn't matter what the parametric analysis parameters are. If you have a moment, use whatever default values are in SAM - Tucson, I think. use a default PV array and battery and model a battery size range like Nick in his webinar. Use my rates, then transpose them - should get the same answer. Either way, it's $3+$11 winter versus $3+$14 summer for demand. Methinks.
Randy

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  • pgilman
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07 Nov 2017 22:02 #5713 by pgilman
Replied by pgilman on topic Modeling On-peak Demand
Hi Randy,
Could you [url=mailto:sam.support@nrel.gov?subject=TOU%20and%20flat%20demand%20rates t=_self]email me[/url] the file you set up for this? I want to make sure to use the same demand rate structure as you.
Thanks,

Paul.

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