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Battery Energy Storage Systems: demand limit during day, charge overnight

asked 2025-09-12 13:26:12 -0500

Greg Estep's avatar

updated 2025-09-12 13:28:36 -0500

Hello all, I'm playing with an onsite PV and battery storage system. I want to net meter the PV system, so that it provides as much power to the building as possible. If there is surplus, charge the battery. I think this is captured in the object ElectricLoadCenter:Distribution with generator op scheme type: baseload. I set the buss type to DC with inverter and DC storage, and add the inverter and converter objects. But what storage operation scheme? None of the schemes achieves the following desired control:

discharges Battery to maintain facility demand during the day (peak hours) (this works with scheme FacilityDemandLeveling), then charges battery from grid regardless of facility demand overnight (off peak) (this does not work for FacilityDemandLeveling).

Has anybody run into this problem? It seems like an obvious control strategy. use storage to shave demand during peak, and charge from grid off peak. let me know, Greg

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answered 2025-09-16 15:02:19 -0500

We have done battery modeling in EnergyPlus where we schedule the battery charging/discharging based on on-peak and off-peak utility periods. To do this, you set TrackChargeDischargeSchedules for the Storage Operation Scheme and then assign schedules for Storage Charge Power Fraction Schedule Name and Storage Discharge Power Fraction Schedule Name.

Assuming you need more control than that, you could go one step further and use EMS to actuate the schedule values based on what's happening in the building. You'd have to play around with which EMS calling point to use, and its possible you won't find a calling point that actually will discharge the battery for the current timestep (as opposed to the following timestep), but I really don't know.

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Thank you Shorowit. I agree that the EMS would be the way to achieve this control. I'm glad that I wasn't missing a standard E+ settings of operation schemes to do this. I must say that I am surprised. This method of control seems obvious to me.

Greg Estep's avatar Greg Estep  ( 2025-09-18 09:26:48 -0500 )edit

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Asked: 2025-09-12 13:26:12 -0500

Seen: 1,110 times

Last updated: Sep 16