Hi Vikram,
Thank you for sending the files with detailed descriptions.
I think this may be a bug -- it looks like SAM is using the Buy Rate on the Electricity Rates page to calculate an electricity purchase amount for grid power used to charge the battery as an annual operating expense even when you choose
No Electricity Rate on the Electricity Rates page. You can verify the issue by looking at the "Electricity purchase ($)" line item on the Cash Flow tab, and also by going to the Data Tables tab, and displaying the annual "Annual energy imported from grid (kWh)" and "Electricity purchase ($)" variables. (Note that both inflation and the electricity bill escalation rate apply to the electricity purchases.)
In the meantime, a workaround for a front-of-meter storage system (PV Battery or Generic System Battery with one of the PPA financial models models) if you want to treat electricity purchases for charging the battery as negative revenue:
- On the Electricity Rates page, choose Enable Electricity Rate (from the blue drop-down list at the top of the page) so you can see the rate structure.
- Choose the Buy all / sell all metering option.
- Set the Buy Rate to zero.
- Choose No Electricity Rate.
We are investigating further and will fix this for the next release. See
github.com/NREL/SAM/issues/370 to follow our progress.
Best regards,
Paul.