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

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.
 

Hi Pauls,
Many thanks for your clear explanation. It really helped me understand the dispatch settings in SAM better.

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. 

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.

Hello Paul, this is Ramiro,  I am trying also to do a simulation with PV+BESS and I have a similar issue, not the same but the same idea. Here is it, hope you can help me.

I want that the excess energy from AC system charges the BESS during first hours of day, but I want to apply some kind of priority.  I have pleany PV energy so I think it willl be possible to export to grid to meet my grid limit, but also at the same time charge BESS.  For that in my dispatch I cheacked the two boxes in the same Period 3.  Because there will be some good shiny days I want that PV energy goes to grid, also could charge BESS but I want to maintain priority on the grid export because I have a demand firm contract to mantain.    (my BESS is AC coupled by the way).  

When I run the simulation under this configuration, all the energy goes only to charge BESS and the export enery drops... and if I choose not to Charge from System, then I get too much curtailment loss energy, and I want that energy to use it and not loss it. 

Can you help how to set up to give some priorities.

Thanks

Ramiro Bravo

  

 

Hi Ramiro,

From your screenshot, it looks like you are modeling a system with battery storage and a front-of-meter (FOM) financial model like the PPA Single Owner model.

There is not an option to prioritize grid exports for the manual dispatch option.

You might try using the automated dispatch option on the Battery Dispatch page and then using time-of-delivery (TOD) factors on the Revenue page to adjust the price of electricity to make it economically attractive to export power to the grid. You can also adjust prices on the Electricity Purchases page to determine the cost of purchasing electricity from the grid to charge the battery.

Best regards,
Paul.