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System Advisor Model (SAM)

LEAC and Energy Rates on Guam

frohro
Topic Author

27 Jan 2020 07:27 #7900 by frohro

Replied by frohro on topic LEAC and Energy Rates on Guam

Hi Paul,
I used the SAM gui to simulate a PVwatts system on Guam, without letting the LEAC change as a function of time to make sure it was worth simulating what happens with a changing LEAC. I was using the beta version of SAM. Now I'm wondering if I should have used the release version of SAM to do that. I want to generate a .json file and import it in PySAM. Are they compatible?
Thanks,
Rob
P.S. It would be really nice if there were some examples using pvsamv1, utilityrate5 and cashload. Can you point me to any?

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frohro
Topic Author

27 Jan 2020 07:35 #7901 by frohro

Replied by frohro on topic LEAC and Energy Rates on Guam

Hi Paul,
I think I found my answer. PySAM.Pvwattsv7 does not exist, but PySAM.Pvwattsv5 does.
I'd still like some examples.
Thanks,
Rob

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pgilman

27 Jan 2020 17:32 #7902 by pgilman

Replied by pgilman on topic LEAC and Energy Rates on Guam

Hi Rob,

The JSON inputs file you generate with different versions of SAM are not necessarily compatible because different versions of SAM run different versions of SSC, and SSC inputs may change between versions.

As you discovered, the Beta version of SAM 2020 uses pvwattsv7 instead of pvwattsv5, and pvwattsv7 does not exist in older versions. The SAM release notes list differences between versions, and also identify the SSC version number associated with each version of SAM:

nrel.github.io/SAM/doc/releasenotes.html

As for examples, I will look into getting some posted.

Thanks,
Paul.

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frohro
Topic Author

28 Jan 2020 00:50 #7904 by frohro

Replied by frohro on topic LEAC and Energy Rates on Guam

Hi Paul,
I'm running into another problem. The beta version has Grid Limits, which I need, as GPA allows us only 100 kW, but the 2018 version does not have Grid Limits. It looks like this means that I need a PySam wrapper for an updated version of utilityrate5 or cashmodel. Is the PySAM wrapper updated with grid limits?
I'm able to get some ball park estimates with the 2020 beta version of SAM ignoring LEAC changes, but the issue here is that in 2022 GPA is putting in 200MW of solar generation, and this is going to approximately reduce the LEAC charges from $0.15/kWh to $0.10 or so. I really need to see what happens with the step going down to $0.08/kWh. In addition to this, GPA is doing everything they can to change the net metering to just reimbursing avoided cost, which I was hoping to model with variable charges. I'm just wondering if I should rethink my plan. What is the best way to deal with these variable rates? I'm open to any ideas.
Thanks,
Rob

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frohro
Topic Author

28 Jan 2020 06:54 #7906 by frohro

Replied by frohro on topic LEAC and Energy Rates on Guam

Hi Paul,
I found that it would be handy to be able to use the sdktool. I'm using linux and when I search my filesystem for sdktool, I find it in the source code (which I still haven't successfully built), but not in the binary installations? Where do I get a binary version?
Thanks,
Rob

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pgilman

29 Jan 2020 00:10 #7909 by pgilman

Replied by pgilman on topic LEAC and Energy Rates on Guam

HI Rob,

We just released PySAM 2.0.2, which is based on SSC 233 and should include the grid limit and other new features currently available in the Beta version:

nrel-pysam.readthedocs.io/en/master/Version.html

See the SAM release notes for information about the different SAM and SSC versions:

nrel.github.io/SAM/doc/releasenotes.html

One option for dealing with changing rate structures might be to run a separate simulation for each year of the cash flow to calculate an array of annual bill savings over the financial analysis period, and then use that array as input to the cashloan module. That would make it possible to change the electricity rate inputs on a year-by-year basis.

Best regards,
Paul.

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