Issue with BESS not charging from curtailed power under interconnection limit in

  • Paul Gilman
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12 Sep 2025 15:17 #14283 by Paul Gilman
Hi Ms. Loan,

I think there is a problem with the logic that controls when the check boxes are enabled and disabled. To enable Battery can garge from grid-limited power, the following must be true:
  • On the Battery Dispatch page for BTM batteries, either Manual dispatch or Retail rate dispatch is checked; for FOM batteries, either Automated dispatch or Manual dispatch is checked.
  • On the Battery Dispatch page, Battery can charge from system is not checked.
  • On the Grid Limits page, Enable interconnection limit is checked or at least one value in the curtailment array is less than 1e+38.
The problem is that Battery can charge from system is disabled for manual dispatch so you can't clear the check box. In order to clear the check box:
  1. Temporarily change the dispatch option to Peak shaving for BTM batteries or Automated dispatch for FOM batteries.
  2. Clear Battery can charge from system.
  3. Change the dispatch option back to Manual dispatch.
Best regards,
Paul.
 

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  • Đỗ Thị Loan
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13 Sep 2025 08:32 #14287 by Đỗ Thị Loan
Hi Pauls,
Many thanks for your clear explanation. It really helped me understand the dispatch settings in SAM better.

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  • Nicolas Machuca
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30 Dec 2025 08:26 #14430 by Nicolas Machuca
Hello Paul,I hope you’re doing well.I’m facing a similar issue to the one I described in my previous message. In this case, I’m working with a PV + BESS plant consisting of 48 MWdc of solar and a 28 MW / 7-hour BESS.
The plant can dispatch energy to the grid and charge the battery when generation is available, and it can also charge the BESS from the grid when solar generation is insufficient. However, there is a limitation on grid charging: the BESS cannot charge more than 15 MW from the grid.
I tried to address this by setting a 50% grid charging rate in the Battery Dispatch settings, but it didn’t work as expected. Is there a way to explicitly account for this grid charging limitation in the PV+BESS dispatch logic?I’ve attached the model and pcitures for reference.

Hope you are your team have a good New Year celebration. 

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  • Paul Gilman
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05 Jan 2026 10:08 #14434 by Paul Gilman
Hi Nicolas,

Adding a grid import limit for battery charging is on our wish list:  github.com/NREL/SAM/issues/1957 .

Thank you for letting us know this feature would be useful to you.

Best regards,
Paul.

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