Storage

To view the PV Storage page, click PV Storage on the main window's navigation menu. Note that for the PV Storage page to be available, the technology option in the Technology and Market window must be Photovoltaics - PVWatts Performance Model.

The PV Storage page allows you to specify the characteristics of the battery storage system.

Note. Solar Advisor's PV storage feature is currently under development. The current implementation is intended for testing purposes. Feel free to experiment with the feature. If you have questions or feedback about modeling battery storage in Solar Advisor, please contact Solar.Advisor.Support@nrel.gov.

The following information will help you experiment with the PV storage feature:

•	The battery parameters determine the basic charging characteristics of the battery system.

•	The battery's operation is determined by the timing control options and the schedule matrices.

•	You can visually explore the results in DView to see how the model dispatches energy from the photovoltaic array, grid, and to and from battery.

Input Variable Reference

Battery Parameters

Variable	Description	Units
Total Battery Capacity	The total battery bank storage capacity in kWh. (kWh = Ah × V)	kWh
Roundtrip Efficiency	The battery's round-trip efficiency. Typically between 70% and 85% for batteries used in photovoltaic systems.	%
Initial Stored Energy	Battery state of charge at the beginning of the simulation. A fully charged battery would have an initial stored energy equal to the total battery capacity. A fully discharged battery would have an inital value of zero.	kWh
Min. Allowable State of Charge	The minimum battery capacity as a percentage of the total battery capacity.	%
Hours to Fully Charge/Discharge	The time to fully discharge the battery bank at the maximum discharge rate.	hours
Max. Charge/Discharge Power	The maximum charge and discharge rate. Calculated by dividing the total battery capacity by the hours to fully charge/discharge.	kW

Solar Array Operation

Option	Description
Disable Solar Array Power Output	Choose this option to model a system with a load served by the grid and a battery, but no photovoltaic array. This option makes it possible to evaluate the cost of a battery storage system.

Battery Dispatch Timing Control

Option	Description
Force charging from the grid	Energy from the grid is used to charge the battery during hours when the battery capacity is at less than 100% of the total battery capacity.
Allow discharging of the battery?	Energy can be drawn from the battery bank.
Allow charge (from excess solar)?	Energy can be delivered to the battery bank from the solar array during hours when the solar array power exceeds the load requirement.

Battery Dispatch Control

The battery's operation is determined by the three timing control options and how they are assigned to the dispatch schedule matrices. The following tips will help you experiment with the dispatch controls:

•	For each of the four periods, you can assign any combination of the three timing control options, which are defined above.

•	The two matrices allow you to define a separate battery dispatch control schedule for weekdays and weekends.

•	To assign a period to a month and hour of day, select cells in a matrix and type a period number. For example, to assign Period 3 to 6 am through 5 pm from June through July, select the cells in the June and July rows and 6 am through 5 pm columns and type the number 3.

•	When you assign a period to a matrix, Solar Advisor applies the timing controls that you checked for the period to the times indicated in the matrix.