1. Sai Moorty ERCOT Integration Options into ERCOT systems

2. 2 Photovoltaic Resource CIM Model (Network Model Management System-NMMS) –Similar to current Generation Resource Single point of injection into grid Single Settlement Point High and low limits –There are other attributes (or lack of) that need more discussions when it comes to modeling: New Resource Type No Synchronous machine with inertia Invertor modeling Reactive capability curve different Short circuit parameters Other?

3. 3 Photovoltaic Resource Energy Management System (EMS) Applications like State Estimation, Power Flow, Contingency Analysis will have no change or minimal change. Currently identified EMS applications that need to be modified or new are: –MODIFICATION: Ancillary Service Capacity Monitor There may be a need to modify this application to take into account intermittent nature of solar due to cloud cover etc. Note: currently Wind Resources have resorted to not carrying Ancillary Service Responsibilities. –MODIFICATION: Online Transient/Voltage Stability Analysis There may be a need to change this application if current capabilities cannot model Photovoltaic Resource correctly

4. 4 Photovoltaic Resource Energy Management System (EMS) –NEW: Solar potential forecasting application Short Term : 5 minute granularity for a rolling window looking out for the next 2 hours Mid Term : 1 hour granularity for a rolling window looking out for the next 2-7 days. Input to Solar potential forecasting application (every 30 seconds via telemetry or other process?): –Cloud cover monitor –Solar farm latitude, longitude, alignment of solar panels, and placement angle off horizontal –Air temperature, Back of panel temperature –Wind speed, Wind direction –Global horizontal Irradiance –For concentrated PV installations, in addition to the above, direct normal Irradiance shall be telemetered

5. 5 Photovoltaic Resource Market Management System (MMS) The products that are available are Energy (MWHr) and Ancillary Service Capacity (MW). Energy (MWHr) is procured in the Day-Ahead Market (DAM) in terms of MW on a hourly granularity Energy (MWHr) is procured in the Real-Time Maket (SCED) in terms of MW every 5 minutes and is settled on a 15-minute basis Ancilary Service Capacity (Regulation Up, Regulation Down, Responsive Reserve, Non-Spin) is procured in terms of MW on a hourly granularity in the Day-Ahead Market, Supplementary Ancillary Service Market in the adjustment period and Resources can assume AS responsibility via bilateral trades

6. 6 Photovoltaic Resource Market Management System (MMS) As far as the Day-Ahead Market and Real-Time Markets, our current understanding is that Photovoltaic Resources will not require any modifications to the Market Systems. Expectations is that Photovoltaic Resources will be very similar to Wind Resources as far as the Market Systems (including Reliability Unit Commitment) are concerned.

7. 7 Energy Storage Resource Salient Features of a Energy Storage resource Do not generate electrical energy like power plants (burning fuel or converting external energy source like wind) –Electrical energy is produced by time-shifting i.e. electrical energy withdrawn from the grid over a particular time period and stored (in some form) and subsequently injected back into the grid at another later period of time Electrical energy consumed is not like loads –Electrical energy not used for producing products or heating or cooling or lighting. Electrical energy is stored for later release back into the grid. Bi-directional, i.e. they can produce or consume electrical energy Electrical energy can be stored for some period of time

8. 8 Energy Storage Resource Salient Features of a Energy Storage resource (continued) Typically, are fast in responding to control signals –Discharge and charging rates are high. Typically, Reactive capability in all four quadrants

9. 9 Energy Storage Resource – Modeling parameters ParameterPhysical UnitDescriptionGeneration Resource Equivalent Max Storage CapacityMWHrMax nameplate energy storage capability n/a Max Storage LevelMWHrMax operating energy storage capability n/a Min Storage CapacityMWHrMin nameplate energy storage capability n/a Min Storage LevelMWHrMin operating energy storage capability n/a Storing Energy Efficiency% Once fully charged, the Percentage of energy compared to max storage level, needed to remain charged at max storage level n/a Max MW Discharging Power MW Max operating MW discharging power HSL Min MW Discharging Power MWMin operating MW discharging power LSL

10. 10 Energy Storage Resource – Modeling parameters ParameterPhysical UnitDescriptionGeneration Resource Equivalent Discharging Ramp RateMW/minRate for discharging in MW/minUp Ramp Rate Min Duration of discharge minMin time to fully discharge from Max Storage Level n/a Discharging efficiency%Percentage of energy losses during discharge n/a Max MW Charging PowerMW Max operating MW charging power MPC Min MW Charging PowerMW Min operating MW charging power LPC Charging Ramp RateMW/minRate for charging in MW/minDown Ramp Rate Min Duration of chargeminMin time to fully charge from Min Storage Level n/a Charging efficiency%Percentage of energy losses during charge n/a

11. 11 Energy Storage Resource – Modeling parameters ParameterPhysical UnitDescriptionGeneration Resource Equivalent Min Time in Charging Mode min Minimum time to be in charging mode Min Up Time Min Time in Discharging Mode min Minimum time to be in discharging mode Min Up Time Min Time in Offline Modemin Minimum time to be in offline mode Min Down Time Max Number of Off-To- Charging Transitions Maximal number of charging cycles in a day Max Number of Starts Max Number of Off-To- Discharging Transitions Maximal number of discharging cycles in a day Max Number of Starts Time to transition from charging to discharging min n/a Time to transition from discharging to charging min TBD

12. 12 Energy Storage Resource CIM Model (Network Model Management System-NMMS) –Detailed discussions with Resource Entities, QSEs are required to get a common understanding of the modeling requirements –Modeling of Storage Resources can also include aggregation of small storage resources (similar to Aggregated Load Resources)

13. 13 Energy Storage Resource Energy Management System (EMS) Applications like State Estimation, Power Flow, Contingency Analysis will have no change or minimal change. Currently identified EMS applications that need to be modified or new are: –MODIFICATION: Ancillary Service Capacity Monitor There may be a need to modify this application to take into account the energy storage level. –MODIFICATION: Online Transient/Voltage Stability Analysis –There may be a need to change this application if current capabilities cannot model Energy Storage Resource correctly

14. 14 Energy Storage Resource Energy Management System (EMS) –NEW: Telemetered quantities – for example Stored Energy Level

15. 15 Energy Storage Resource Market Management System (MMS) The products that are available are Energy (MWHr) and Ancillary Service Capacity (MW). Energy (MWHr) is procured in the Day-Ahead Market (DAM) in terms of MW on a hourly granularity Energy (MWHr) is procured in the Real-Time Maket (SCED) in terms of MW every 5 minutes and is settled on a 15-minute basis Ancilary Service Capacity (Regulation Up, Regulation Down, Responsive Reserve, Non-Spin) is procured in terms of MW on a hourly granularity in the Day-Ahead Market, Supplementary Ancillary Service Market in the adjustment period and Resources can assume AS responsibility via bilateral trades

16. 16 Energy Storage Resource Market Management System (MMS) Due to the limited energy available from Energy Storage Resources, care will have to be taken as to which products are most suitable. There are compliance penalties if Resources do not perform to their obligations Currently there is a pilot project in the works “ Fast Responding Regulation Service” to evaluate the performance of Resources capable of extremely fast regulation service. Storage Resources like Batteries can participate. Introduction of any new technology neutral product will need to be vetted through the stakeholder process

17. 17 Summary ERCOT SystemPhotovoltaicEnergy StorageComment Registration (RARF)Small-MediumLargeDependent on modeling NMMSMediumLarge Schema changes will need to be scalable to anticipated other new types of Resources EMSMediumLarge Additional telemetry and new applications MMS SmallLarge Photovoltaic similar to Wind from MMW perspective Energy Storage will require significant changes S&B?? Depends on outcome of stakeholder process TBD ? ?