T&D Losses

1. T&D Losses Reflecting Losses in DR within ERCOT August 22, 2012

2. Losses Introduction • Loss factors are calculated on a 15 minutes basis to estimate amount of electricity lost in the transmission and distribution system • TDSPs create and assign loss codes (often, although not necessarily, based upon voltage level) to ESIIDs and provide the coefficients used in the calculation of loss factors • [Metered Load * (1/(1-DLF))] * (1/(1-TLF))  Unaccounted for Energy (UFE) added after losses Reflecting T & D Losses in DR 08-22-12

3. Losses Introduction (continued) • Losses are forecasted for two days in advance with actual losses calculated the day after flow • QSEs are charged but load typically pays for these losses, although the load never sees that electricity pass through it’s meter • This is not about losses behind the meter, but rather describes the losses between two accepted lines of demarcation – the generation meter and the load meter Reflecting T & D Losses in DR 08-22-12

4. Concept • The grid impact of 1 MW of metered demand response is not the same as 1 MW of additional generation • 1 MW of generation satisfies something less than 1 MW of metered load as electricity due to losses • Conversely, 1 MW of metered load curtailment replaces something more than 1 MW of generation as losses are avoided Reflecting T & D Losses in DR 08-22-12

5. Losses Illustrated • Transmission Level service • 1.3% to 2.6% • Distribution Level service – Primary • 2.0% to 11% 9.7 MWs 8.9 MWs • Distribution Level service – Secondary • 4.0% to 19% 8.1 MWs 30 MWs Reflecting T & D Losses in DR 08-22-12

6. Suggested Solution • Demand Response that is offered in any ERCOT related program or market should be grossed up to reflect the applicable transmission and distribution losses that would have applied to measured curtailed volumes Reflecting T & D Losses in DR 08-22-12

7. Benefits • More equitably compensates DR for grid impact • Recognizes true impact on grid including reducing stress on distribution assets • Volumes of offered demand response not curtailed are adjusted for losses by LSE for retail electricity billing • Most beneficial for smaller customers • Untapped (and needed) DR potential • Utilize smart meters • Inline with goals of SB1125 Reflecting T & D Losses in DR 08-22-12

8. Benefits (continued) • Aligns ERCOT with other regions for DR reporting • Most other ISOs with a history of successful demand response programs incorporate this concept into their programs, including PJM, ISO-NE, and NYISO • Facilitates LMP – G for Real Time Market dispatch • LMP – G settlement would gross up curtailed volumes to bill customer for G; curtailed volumes should also be grossed up • Should speed implementation of Loads in Real Time Market dispatch as methodologies will be defined Reflecting T & D Losses in DR 08-22-12

9. Issues List • Items to be considered: • UFE • NOIE losses • Impacts for LR • Impacts to ALR • Impacts to CLR • ERS Settlement calculations • ERS Compliance calculations Reflecting T & D Losses in DR 08-22-12

10. UFE • Including UFE will foster consistency. • If participating in Real Time Market, and with the LMP – G concept, an LSE would be charged for the same volume as the DR QSE would be paid • Customers receiving statements would see same volumes • Including UFE will increase uncertainty, making it more difficult for: • Compliance • Reserves procurement in SCED • Budgeting • Recommendation: Do not adjust for UFE • Differences should be small so benefits will be limited Reflecting T & D Losses in DR 08-22-12

11. NOIE Losses • NOIEs are not required to provide Distribution Loss Factors to ERCOT • Providing DLFs for use only for demand response opens potential for gaming • Recommendation: All meters behind NOIE territories are grossed up for only the Transmission Loss Factors Reflecting T & D Losses in DR 08-22-12

12. Impacts for LR • QSEs determine volumes to schedule based upon expected load and forecasted losses • Actual loss factors not available until T+1 and therefore cannot give real time awareness • Telemetry provided to ERCOT would be grossed up by the appropriate forecasted loss factors • [Metered Load * (1/(1-DLFForecasted))] * (1/(1-TLFForecasted)) • LR settlement is unchanged as it is based upon scheduled volumes • LR compliance is unchanged since telemetry would be grossed up Reflecting T & D Losses in DR 08-22-12

13. Impacts for LR (continued) • Should the telemetry be grossed up by ERCOT or by the QSE? • Implementation at ERCOT would entail a single change vs. all QSEs making changes • Implementation at QSE would ensure QSE personnel see the values used for meeting their obligations and those used for compliance • If a QSE doesn’t implement, harms only that QSE and their customers • Recommendation: QSEs responsible for grossing up for losses • Would introduce some (likely very small) level of loss forecast risk Reflecting T & D Losses in DR 08-22-12

14. ERS Compliance Calculation - Alternate • Alternate • Contract Capacity (CC) offers could be maximized by QSEs based upon expected actual loss factors • Maximum Base Load (MBL) submitted based upon metered value but grossed up for losses by ERCOT for availability and performance calculations • Availability calculation to be based upon CC, grossed up metered volumes and MBL (DLF and TLF) • Performance compares grossed up metered values vs. grossed up MBL Reflecting T & D Losses in DR 08-22-12

15. ERS Compliance Calculation - Default • Default • CC offers could be maximized by QSEs based upon expected actual loss factors • Availability calculation to be based upon CC and grossed up metered volumes (actual DLF and TLF) • Performance compares grossed up metered values vs. CC Reflecting T & D Losses in DR 08-22-12

16. ERS Compliance Calculation - Risks • Risks • May increase availability risk as actual loss levels will not be known in advance • Difference of submitting grossed up CC and metered MBL is a potential source of confusion • QSEs that offered based upon metered volumes for consistency and to avoid confusion would reduce availability risk and not be affected for performance risk Reflecting T & D Losses in DR 08-22-12

17. ERS Settlements Calculation - Settlements • Settlements unchanged • Would continue to use the availability and performance metrics to get combined performance factor • Costs allocated based upon load ratio share Reflecting T & D Losses in DR 08-22-12

18. Next Steps • Identify / resolve outstanding issues: • LR • ERS • ALR • CLR • LR – change in Operating Guide? • ERS – NPRR with small changes to compliance sections Reflecting T & D Losses in DR 08-22-12

19. Chair Contact Information • Tim Carter • 713-646-5476 • tim.carter@constellation.com Reflecting T & D Losses in DR 08-22-12