Off-Grid Fuel Cell/Battery/PV model?

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ritagperan
Topic Author

18 May 2023 14:56 #12154 by ritagperan

Off-Grid Fuel Cell/Battery/PV model? was created by ritagperan

Hello!

I am trying to model a off-grid system that consists of PV, loads, a battery as the first backup and a DMFC fuel cell as a second backup.
In my system, the PV charges the battery whenever the production exceeds the loads for future use. Whenever there is no more energy in the battery, then the fuel cell turns on to supply for the system.
I have issues modelling this, and I think the problem is in the Dispatch settings, I have the following:
-Fuel Cell operation- Follow electric load
-BTM - Charge from system only when system output exceeds load
-Discharge battery only when load exceeds system output
There are errors that appear and I dont know what I am doing wrong, I have tried several options and it doesn't work :(
Is there a way I can prioritize first the battery operation then as a backup the fuel cell?

Thank you in advanced!
Rita

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pgilman

18 May 2023 15:12 #12155 by pgilman

Replied by pgilman on topic Off-Grid Fuel Cell/Battery/PV model?

Hi Rita,

Can you tell me what specific errors you are seeing? If you don't mind attaching your .sam file, I can try to help you troubleshoot.

Best regards,
Paul.

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ritagperan
Topic Author

18 May 2023 15:26 #12156 by ritagperan

Replied by ritagperan on topic Off-Grid Fuel Cell/Battery/PV model?

Hello,Thanks for the reply.The errors are: Simulation battery failed :precheck input: variable 'dispatch_manual_btm_discharge_to_grid' (Periods 1-6 behind the meter discharging to grid allowed?) required but not assignedbatt_annual_discharge_energy not assignedSimulation cashloan failed :batt_annual_discharge_energy not assigned

Please find attached the file BW1

BW1.sam

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pgilman

18 May 2023 21:34 #12159 by pgilman

Replied by pgilman on topic Off-Grid Fuel Cell/Battery/PV model?

Hi Rita,

Thank you for describing the error and providing the file.

This is a bug. We will fix it for the Fall 2023 release: github.com/NREL/SAM/issues/1406

In the meantime, as a workaround, please run this LK script to fix the problem:

Download the attached fuel-cell-battery-fix.zip file and extract it into a folder so that you have a folder that contains the .lk files and three .json files.
Start SAM, and click Open script from the Welcome page. (If SAM is already open, close it first.)
Go to the folder containing the fuel-cell-battery-fix.lk file and open it.
Click Run at the top of the script editor window.
When the script finishes, close the script editor and close SAM.
Start SAM and open your Fuel Cell file and confirm that the simulation runs without generating a message.

Please let me know if you have trouble with the script, or if you find any other problems with the manual dispatch option.

Best regards,
Paul.