1 Distributed Generation Task Force November 5, 2007

2 ERCOT requires a fifteen (15) minute settlement interval Vast majority of Customers do not have this level of granularity Profiles are created using adjusted static models Models estimate customer level interval load based on calendar-type data (season, day of week, time of day) weather data (temperature, wind-speed, cloud- cover, dew-point) Backcasted Profiles are generated the day following a trade day and used for all settlements (initial, final and true-up) Load Profiling Converts monthly kWh reads to fifteen (15) minute intervals Enables the accounting of energy usage in settlements ERCOT Load Profiling

3 ERCOT Load Profile Models are documented in Appendix E of the Load Profiling Guide on the ERCOT website ERCOT Load Profiling

4 ESI IDs are linked to Load Profile Models by their Load Profile ID Rules for assigning ESI IDs to Load Profile ID are also documented in Appendix D of the Load Profiling 01/Appendix_D_-_Profile_Decision_Tree_ xls ERCOT Load Profiling

5 3 Load Profile Groups 10 Segments Residential (2) Low-Winter Ratio (Non-electric Heat) (Non-electric Heat) High-Winter Ratio (Electric Heat) (Electric Heat) Business (5) Low Load Factor Medium Load Factor High Load Factor Non-Demand IDR Default OGFLT Non-Metered (2) Lighting (Street Lights) Flat (Traffic Signals)

6 8 ERCOT Weather Zones

7 8WeatherZones 10 Profile Segments 80 Load Profiles Total Profiles

8 Profiling Example

9 Profiling Example One Day

10 SunriseSunset Load Generation Net Load Load as Profiled 105 kWh of load is offset with 24 kWh of photovoltaic generation behind the meter Standard RESHIWR profile allocates the 81 kWh of net load for the day without considering the presence of generation behind the meter Standard Profiles with Distributed Generation

11 Load Generation Net Load Load as Profiled SunriseSunset Standard Profiles with Distributed Generation 58 kWh of load is offset with 34 kWh of generation behind the meter Standard RESHIWR profile allocates the 24 kWh of net load for the day without considering the presence of generation behind the meter Net load of 24 kWh reflects 5 kWh of reverse registration on the meter

12 Generation Load Net Load Load as Profiled SunriseSunset Standard Profiles with Distributed Generation 58 kWh of load is offset with 34 kWh of generation behind the meter Standard RESHIWR profile allocates the 29 kWh of net load for the day without considering the presence of generation behind the meter Meter Detent prevents 5 kWh of reverse registration on the meter

13 Excerpts from the Load Profiling Guide: Chunking Profiling Methodology Description The chunking method of Load Profiling for TOU customers means that a standard profile is applied to the customer’s consumption data for a meter reading period. However, the energy for each TOU period in the Load Profile is scaled so that it is equal to the metered energy (kWh) for the TOU period. For each TOU period within a meter read cycle, the metered consumption during the Time-of-Use (TOU) period is allocated to time intervals within the TOU period in proportion to the Load Profile level at each interval in that period. Time-Of-Use Methodology

14 Assumed detented meter programmed for 3 time of use periods: -TOU 1 = (Midnight – 7:45 am) & (5:15 pm – Midnight) -TOU 2 = (7:45 am – 9:45 am) & (3:45 pm – 5:15 pm) -TOU 3 = (9:45 am – 3:45 pm) Careful specification of the TOU periods can allow chunking the standard profile to reasonably approximate the net load of the ESI ID TOU Profiles with Distributed Generation Net Load Load as Profiled

15 In- and Out-Meters programmed for 3 time of use periods: -TOU 1 = (Midnight – 7:00 am) & (7:45 pm – Midnight) -TOU 2 = (7:00 am – 8:15 am) & (6:00 pm – 7:45 pm) -TOU 3 = (8:15 am – 6:00 pm) TOU periods based on anticipated shape of net load during August Both meters detented to measure load flow in one direction Flow into ERCOT profiled with a flat profile (for this example) TOU Profiles with Distributed Generation Net Load Load as Profiled Net to ERCOT Net as Profiled

16 TOU Profiling Considerations  Approval of a new TOU schedule requires Submission of an LPGRR, and Stakeholder Approval Process Up through TAC  Minor ERCOT system changes (table update) provided no more than 4 TOU periods per day type  Flexible TOU periods and day types Periods not necessarily contiguous Up to 7 day types  Flexible definition and number of Seasons TOU periods can be different across seasons  If energy flow into ERCOT is NIDR metered, development of a profiling methodology would be needed to create settlement interval data Accuracy would be problematic Flat profile would be easiest to create Obtaining higher level of accuracy may not be cost effective  System changes required to accommodate profiling for energy flow into ERCOT (resource data)  TDSP meter limitations may be different than ERCOT limitations

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18 Sunrise and Sunset Times

19 Excerpts from the Load Profiling Guide: 12.5 Groups of ESI IDs Eligible to Become Profile Segments For a group of ESI IDs to be a distinct profile segment, the group shall satisfy the following requirements: The group is based on readily identifiable parameters, which are not subject to frequent change. The group is reasonably homogeneous as defined in Section , “Homogeneity.” The group is sufficiently different from other existing profiles as defined in Section , “Difference from Current Profiles.” The group is of sufficient size to justify its own profile segment as defined in Section , “Size.” 12.6 Information Required with Request for Change All requests shall include the following: Unambiguous Group Identification Difference from Current Profile Segments Size Homogeneity Quality Assurance Methodology for ESI ID Identification LPG Requirements for New Profile

Source: InfinitePower.org Insolation Across Texas

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25 New Load Profile Considerations  Market Participant submit a request  Evaluation Time for request  Load Profiling Methodology Lagged Dynamic  Approved for new profiles but system changes needed for implementation  Dynamic sampling required as population increases Static Models  Sample Requirements  Collection of Load Research data (18 – 24 months)  Sample data analysis and model building  Require LPGRR and Stakeholder Approval Process for New Model  150 day Market Notice Required after Stakeholder Approval Process