Battery dispatch behaviour which maximises reliability?

Hi all,

Firstly, thanks to the NREL team for making and maintaining this important tool. Thanks also to Paul for supporting the community.

As renewables penetration increases, there is more focus on the ability to deliver 'firm' renewable power. (See Google's 24/7 renewables initiative, or the 'Round the Clock' PPA auctions in India). So developers need to determine how to meet a fixed minimum amount of power per period, through a blend of RE plants and storage. This issue has of course been important for off-grid hybrid plants for some time. 

I was wondering if SAM's battery model has a dispatch algorithim which maximises reliability. It would be fairly simple behaviour, where the battery would only charge using excess generation after the fixed load is met. And only discharge when the fixed load target is not being met.

I can't see this in SAM, but there's a variable in PySAM which suggests it could be conisdered. (batt_dispatch_charge_only_system_exceeds_load, batt_dispatch_discharge_only_load_exceeds_system).

Thanks for the help with this.

Best regards,
Henry

Hi Henry,

Those dispatch options are available for behind-the-meter batteries. You can find them in SAM on the Battery Dispatch page for a PV Battery, Generic Battery, or Standalone Battery configuration with the Residential, Commercial, or Third Party Host/Developer financial models.

SAM's grid outage model may also help you with this kind of analysis. It allows you to specify a critical load, either as a percentage of the building's electric load, or as a separate time series dataset. You can read more about it in Help:  samrepo.nrelcloud.org/help/grid_outage.htm .

Best regards,
Paul.

Hi Paul,

Thank you for the quick reply, this is quite useful and interesting.

Can behind the meter batteries be modelled with pre-calculated generation load profiles, perhaps using the combined case feature? So I could first model seperate wind and solar plants, combine their hourly outputs, and then feed that into a 'behind the meter' battery? 

I'll play around to try and find out myself.

Best regards,
Henry

Hi Henry,

You can use the "Generic System-Battery" model and provide an hourly or subhourly generation profile as input on the Power Plant input page.

That model also has an option that adds up the generation outputs of other cases in the file so you could use the combined output of, say, a wind and PV system as the generation profile for the battery to respond to. That is described here in Help: samrepo.nrelcloud.org/help/generic_system_plant.htm .

Best regards,
Paul.