Importing SAM configuration: JSON to python

Ana
Topic Author

19 Mar 2025 17:53 #13965 by Ana

Importing SAM configuration: JSON to python was created by Ana

Hi! After attending the webinar today, I'm trying to configure a residential solar + storage setup, now aided by parameters configured in the SAM UI, exported as JSON, and imported into my python notebook for use.

I am importing them like this, as specified on the SAM defaults documentation :

Code:

import json
import PySAM.Pvsamv1 as PV # Adjusted from Pvwattsv8 since I noticed that this was not one of the exported JSON files
import PySAM.Grid as Grid
import PySAM.Utilityrate5 as UtilityRate
import PySAM.Cashloan as Cashloan

pv = PV.new()
grid = Grid.from_existing(pv)
ur = UtilityRate.from_existing(pv)
cl = Cashloan.from_existing(pv)

dir = "SAM_configuration/"

file_names = ["untitled_pvsamv1"] # "untitled_grid", "untitled_utilityrate5", "untitled_cashloan",
modules = [pv] # grid, ur, cl

for f, m in zip(file_names, modules):
with open(dir + f + ".json", 'r') as file:
data = json.load(file)
print(file)
for k, v in data.items():
print(k)
print(v)
if k != "number_inputs":
m.value(k, v)

Running this code I get an error:

Code:

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
Cell In[29], line 14
     12 print(v)
     13 if k != "number_inputs":
---> 14     m.value(k, v)

AttributeError: "value" error, could not find attribute by that name

It appears to fail on setting:

Code:

batt_adjust_constant 0

after setting all previous parameters as expected.

Is there an issue with the parameter import / setup, or is there a workaround I could pursue?

Relatedly, how could I access details regarding the battery? Even though I have configured it in the SAM UI, it does not appear to have an associated JSON configuration that is exported.

Using SAM:
```
Version 2024.12.12, 64 bit

SSC Version 298: OS X 64 bit GNU/C++ Dec 11 2024 22:29:29
wxWidgets 3.2.6 on macOS Sonoma Version 14.5 (Build 23F79)
Internet connection method: default
Display: 1512 x 982, magnification 1x
```
Attached: JSON files generated by SAM, not including utitled.json, also sccapi.h and scc.dylib. Screenshot of battery configuration in UI.

Attachments:

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Paul Gilman

20 Mar 2025 17:53 #13966 by Paul Gilman

Replied by Paul Gilman on topic Importing SAM configuration: JSON to python

Hi Ana,

There seems to be a problem with the battery_adjust variables. As a workaround, please try deleting the following variables from the untitled_pvsamv1.json file:

batt_adjust_constant
batt_adjust_en_timeindex
batt_adjust_en_periods
batt_adjust_timeindex
batt_adjust_periods

After deleting those files, you'll need to do the following to get a test pvsamv1 simulation to run:

1. Set the value of 'load' in the untitled_pvsamv1.json file to an array with the same length as 'crit_load'.
2. Set the value of 'solar_resource_file' to a valid path to a solar resource CSV file.

Then, you should be able to run the PV model and show results with:

pv.execute()
print(pv.value('annual_ac_gross'))

The battery inputs are in the untitled_pvsamv1.json file. Many of them have a "batt_" prefix. The are listed in the PySAM documentation for the Pvsamv1 moudule here:

nrel-pysam.readthedocs.io/en/main/modules/Pvsamv1.html#batterycell-group
nrel-pysam.readthedocs.io/en/main/modules/Pvsamv1.html#batterydispatch-group

By the way, those ssc_api.h and ssc.dylib files are not required to run PySAM.

Best regards,
Paul.

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