Appendix A — BESS Dispatch Scenario Definitions

Reference material for the operational scenario checklist in Section 4.

Operational Summary Options:

    
            Scenario
            PV Status
            BESS Status
            Grid Impact
            Primary Value Driver
        

    
            Pure PV
            Exporting
            Idle
            Receiving Power
            PPA Compliance / Base Energy
        

            Split Split
            Exporting
            Charging
            Receiving Power
            Capacity Management
        

            Arbitrage
            Off / Idle
            Discharging
            Receiving Power
            Price Peak Arbitrage
        

            Max Co-Dispatch
            Exporting
            Discharging
            Receiving Power (At POI Limit)
            Resource Adequacy / Emergency Peaks
        

            Grid Charge
            OFf / Idle
            Charging
            Delivering Power
            Low-cost Charging / Grid Curtailed Energy
        


  
  

1. Pure Renewable Generation (PV to Grid)

Description: Solar generation goes directly to the grid.
Operation: The PV inverter converts DC solar power to AC power, routing it straight to the substation.
Battery State: Idle or fully charged.
Timing: Peak daylight hours when grid prices are favorable or contractually required.

2. Simultaneous Generation and Charging (PV to Grid + PV to BESS)

Description: Solar power splits to serve the grid and charge the battery.
Operation: The PV array generates at maximum capacity. A portion of the AC power flows to the grid, while the BESS inverter imports the remaining AC power, converts it to DC, and stores it.
Battery State: Charging.
Timing: Mid-day periods with high solar irradiance and lower grid demand or prices.

3. Clipped Peak Capture (PV to BESS)

Description: Capturing solar energy that would otherwise be lost to inverter clipping.
Operation: When PV DC power exceeds the PV inverter’s AC rating, the system can use the BESS to absorb the excess energy. Note: in AC-coupled systems, this requires the PV inverter to be oversized or configured so the BESS can absorb AC power at the shared bus before the POI limit is hit.
Battery State: Charging.

4. Solar Shifting / Arbitrage (BESS to Grid)

Description: Discharging stored solar energy during peak demand.
Operation: The PV array produces nothing. The BESS discharges DC power, which its dedicated inverter converts to AC and injects into the grid.
Battery State: Discharging.

5. Combined Maximum Discharge (PV + BESS to Grid)

Description: Both systems discharge to the grid simultaneously to meet extreme peak events.
Operation: The PV array generates at capacity, and the BESS discharges at capacity. Constraint: the total combined output cannot exceed the interconnection agreement’s maximum POI limit.
Battery State: Discharging.

6. Grid Charging (Grid to BESS)

Description: The battery charges directly from the wholesale grid rather than the co-located solar.
Operation: The BESS inverter acts as a rectifier, pulling AC power from the grid to charge the battery cells.
Battery State: Charging.

7. Ancillary Services (Regulation & Frequency Response)

Description: Rapidly adjusting power to maintain grid stability.
Operation: The BESS dynamically injects or absorbs power within milliseconds based on grid frequency signals. The PV plant continues its baseline generation or curtails if required.
Battery State: Rapidly cycling between micro-charging and micro-discharging steps.
Timing: 24/7 as dictated by the transmission system operator (ISO/RTO).