Settlement of Residential Photovoltaic (PV) Arrays in ERCOT Load Profiling

1. Hypothetical Examples of How Residential Photovoltaic (PV) ESI IDs Could be SettledERCOT Load Profiling

2. Introduction • There are two options that can be used to settle the outflow for residential photovoltaic (PV) arraysas measured at the point of interconnection for the ESI-id : • Wholesale settlement of the outflow only • Wholesale settlement of all solar generation • settlement of the outflow and • adjustment of the load profile (in order to account for solar generation during all time periods of generation)

3. Settlement of Outflow Only How can the outflow for residential photovoltaic (PV) arrays as measured at the point of interconnection be settled? Some possibilities for allocating the PV-generated outflows: 1. Spread the energy evenly over daylight hours 2. Spread the energy evenly over the peak PV generating hours 3. Spread the energy using a PV model 4. Spread the energy using both a PV model and the existing settlement load profile

4. Settlement of Outflow Only These approaches allocate the solar generation (or outflow) as measured point of interconnection. None of these options adjust the settlement profile of load for solar output (i.e., load is settled using the existing load profile).

5. Examples Following are examples of the Settlement of Outflow Only option for a very low usage residential high winter ratio (RESHIWR) ESI ID in the North Central weather zone.

6. Spread energy evenly over daylight hours

7. Spread the energy over peak PV hours

8. PV generation models • If PV generation models were created, PV generation measured at the point of interconnect could be used to estimate the shape of the PV output to the grid. • To estimate the shape of the PV output to the grid scale the ‘kWh out’ value using the PV generation model.

9. PV generation models

10. PV generation models used with existing load profiles • If PV generation models were created, PV generation measured at the point of interconnect could be used with the existing load profiles to estimate the shape of the PV output to the grid.

11. PV generation models used with existing load profiles

12. PV generation models used with existing load profiles

13. PV generation models used with existing load profiles

14. Settlement of Outflow Only - Analysis • Initial estimates for ERCOT effort of these options: • Spread the energy evenly over daylight hours • small effort (<100k) • 2. Spread the energy evenly over the peak PV generating hours • small effort (<100k) • 3. Spread the energy using a PV model • small effort (<100k) • 4. Spread the energy using both a PV model and the existing settlement load profile • medium effort (<500k)

15. Assumptions • The settlement options included in this presentation assume: • That NIDR generation data as measured at the point of interconnect will be provided to ERCOT for each applicable ESI-id. This will require modifications to the 867 business process at ERCOT. These changes are not accounted for in the ERCOT estimates provided in this presentation. • A registration process is created for ESI-ids that have solar installations. This will include how solar ESI-ids are identified in the ERCOT settlement process.

16. Summary • These approaches allocate the solar generation (or outflow) as measured point of interconnection. • None of these options adjust the settlement profile of load for solar output (i.e., load is settled using the existing load profile). • Questions?

17. Settlement of ‘kWh in’ and ‘kWh out’ • How can settlement reflecting solar generation not measured as outflow be accomplished? • This includes: • settlement of the outflow and • adjustment of the load profile (in order to account for solar generation during all time periods of generation)

18. Example Following is an example of the Settlement of Solar Generation option for a very low usage residential high winter ratio (RESHIWR) ESI ID in the North Central weather zone.

19. Settlement of ‘kWh in’ and ‘kWh out’

20. Settlement of ‘kWh in’ and ‘kWh out’ This approach involves the most significant changes for ERCOT. The exact requirements would need to be defined through the stakeholder process. At a high level, ERCOT estimates that this would be a large effort (<750k). This estimate should be considered a ballpark estimate only due to unidentified requirements at this time.

21. Assumptions • The settlement options included in this presentation assume: • That NIDR generation data as measured at the point of interconnect will be provided to ERCOT for each applicable ESI-id. This will require modifications to the 867 business process at ERCOT. These changes are not accounted for in the ERCOT estimates provided in this presentation. • A registration process is created for ESI-ids that have solar installations. This will include how solar ESI-ids are identified in the ERCOT settlement process. • A new load profile would need to be created.

22. Other Applications The settlement options included in this presentation can be applicable to other renewable technologies. This would require the use of a technology specific model.

23. Questions Questions?