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Outline

Future Ancillary Service Team (FAST) and Technical Advisory Committee (TAC) Workshop #3- An update to the 8/25 version ERCOT Staff September 15, 2014. Outline. Recap and Overview of Schedule Review How AS Requirements are Determined

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Outline

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  1. Future Ancillary Service Team (FAST) and Technical Advisory Committee (TAC) Workshop #3- An update to the 8/25 version ERCOT Staff September 15, 2014

  2. Outline • Recap and Overview of Schedule • Review How AS Requirements are Determined • Review Options on When Quantities are Finalized and Provided to the Market • Discuss Specific Policy Cuts • Update on RFP for CBA • Review Synchronous Inertial Response (SIR) • Next Steps

  3. From July 31 TAC Meeting

  4. Summary of Proposed Future Ancillary Services Current Proposed Regulation Up Fast-Responding Regulation Up Regulation Up Fast-Responding Regulation Up Mostly unchanged Regulation Down Fast-Responding Regulation Down Regulation Down Fast-Responding Regulation Down 59.8 Hz, Limited duration Fast Frequency Response 1 Fast Frequency Response 2 59.7 Hz, Longer duration Responsive Primary Frequency Response SCED-dispatched Contingency Reserves 1 Contingency Reserves 2 Manually dispatched Supplemental Reserves 1 SCED-dispatched Non-Spin Manually dispatched Supplemental Reserves 2 Ongoing development Synchronous Inertial Response

  5. Determining AS Quantities • Determined at lead time(s) defined in AS Methodology • Defines AS Products, settlements, perf. Reqs, etc • Implemented in NPRR AS Framework Expected Operating Conditions • Defines AS requirements as a function of operating conditions • Updated when studies or regulatory requirements are updated • Studies of System performance under different conditions • Updated as needed • Documents AS technical requirements • Defines how operating conditions will be used to determine procurement quantities • Updated Annually Technical Studies Technical AS Reqs AS Methodology • e.g. NERC BAL-003-1 standard Hourly AS Quantities Regulatory Reqs

  6. Determining AS Quantities AS Framework Expected Operating Conditions Technical Studies Technical AS Reqs AS Methodology Hourly AS Quantities Regulatory Reqs

  7. Study results and proposed methods to determine AS Requirements

  8. PFRS and FFRS • Criteria : Frequency nadir shall be equal to or above 59.4 Hz for loss of two largest units. (0.1 Hz margin for the first stage of UFLS at 59.3 Hz) • No angular and voltage instability • Will include • Minimum amount of PFRS • Minimum amount of PFRS and FFRS • Equivalency ratio between PFR and FFR • High Frequency Over-shoot

  9. PFRS and FFRS (Continued) • Minimum Amount of PFR: • BAL-003-1: The ERCOT Interconnection Frequency Response Obligation (IFRO) is currently 413MW/0.1 Hz • No FFR Response is expected for 0.3 Hz band between 60 Hz and 59.70 Hz assuming no FFR1 participation • PFR(min) = 413 MW/0.1 Hz * 3 (since FFR does not respond up to 0.3 Hz deviation) = 1,239 MW • Stability analysis is used to determine • Minimum Amount of PFRS and FFRS • Interdependence ratio between PFR and FFR • Minimum PFR can be changed based on annual review of IFRO by NERC

  10. Minimum Amount of PFRS and FFRS • Numerous frequency stability runs were conducted on multiple scenarios. • Key Assumption: • No wind dynamic models • Load Resources responded within 30 cycles • Governor response modeled only for Resources assigned PFRS in the simulation of a low frequency event • 30% PFRS are provided by Coal units • 70% PFRS are provided by NG units

  11. FFR1(59.8 Hz) Vs FFR2(59.7 Hz) 1 MW FFR1 ≈ 1 MW FFR2

  12. Test: Twelve Study Cases case12 case11 case10 case9 case8 case7 case6 case5 case4 case3 case2 case1 Inertia=2*Kinetic Energy=2*H*MVA

  13. An Example of Case Study Minimum amount of FFR and PFR is determined by preventing frequency from dropping below 59.4Hz for loss of 2 largest units (2750MW)

  14. Preliminary FFR and PFR Study Results

  15. PFR vs FFR (59.7Hz) Result Summary Conclusion: As system inertia increases, FFR/PFR ratio gradually decreases to about 1 where PFR and FFR are approximately same in terms of arresting system frequency

  16. REG-UP and REG-DOWN • Maximum of : • 98.8 percentile of the five minutes net load change and deployment during the 30 days period to the time of the study. • 98.8 percentile of the five minutes net load change for the same month of the previous year • Additional adjustment based on CPS1 score for each hour

  17. Contingency Reserve Service (CRS) • Recover frequency from settling point to 60 Hz • Build in a margin based on the amount of CRS a single Resource can provide • CRS need will be dynamic based on system conditions just like PFRS and FFRS requirement

  18. Supplemental Reserve • 95 Percentile 6-Hour-ahead net-load forecast error • SRS for any 4-hour block is equal to 95 percentile of 6-hour ahead net load forecast error less Reg-Up, Contingency Reserve and portion of combined PFRS/FFRS • For extreme weather condition, SRS requirement to be based on unit forced outage rate This is open to discussion This is open to discussion

  19. Determining AS Quantities AS Framework Expected Operating Conditions Technical Studies Technical AS Reqs AS Methodology Hourly AS Quantities Regulatory Reqs

  20. Efficiency versus Certainty in Setting AS Quantities

  21. Efficiency versus Certainty • Max Certainty: • A fixed amount of a particular service could be procured for every hour based on the amount needed to cover worst case conditions • This would result in too much being procured for most hours • Max Efficiency: • The amount to be procured for each hour of the next day could be set prior to the DA market, based on expected conditions for that next day • This would make it difficult to hedge requirements • Need to determine an appropriate tradeoff • May vary by service

  22. Options for PFRS/FFRS Procurement • ERCOT is offering five different options for procurement of PFRS and FFRS • The options differ based on how early market prefers to know the minimum quantities • Day-Ahead adjustment proposed is consistent with current protocol language and ERCOT does not anticipate performing the day-ahead adjustment routinely • Day-Ahead analysis look at projected net load conditions and unit commitments Please note : The Options discussed for PFRS and FFRS can be tailored for all AS products

  23. Options for procurement of PFRS and FFRS DA: Day-Ahead, MA: Month-Ahead, YA: Year Ahead √: Determine the needs for the entire period ∆: Determine the “incremental” needs based on the system condition

  24. Option I for PFRS and FFRS Requirements Determine a number based on the study performed to simulate extreme condition and procure that amount for all hours

  25. Proposed Options for PFRS/FFRS Requirements Option II • Publish the minimum PFRS and target FFRS requirement and FFR to PFR equivalence ratio by 6am for the next operating day • Posting will include requirements for each hour of the operating day

  26. Option II for PFRS and FFRS Requirements • Publish the requirement in Day-Ahead. AS Requirement Time Real Time Needs Day-Ahead

  27. Proposed Options for PFRS/FFRS Requirements This percentage is open to discussion Option III • Publish the 100% of calculated minimum PFRS and target FFRS requirement, and FFR to PFR equivalence ratio by 20th of each month for the upcoming month • Make any necessary Day-Ahead adjustment and post the adjustments by 6 am for the next operating day • Monthly and Day-Ahead posting to MIS will include requirements and equivalency ratio between FFRS and PFRS, for each 4-hour block of the operating day

  28. Options III for PFRS and FFRS Requirements • Publish the requirement using 100% of the need Month-Ahead • Day-Ahead : determine incremental need AS Requirement Time Real Time Needs 100% of Month-Ahead Day-Ahead

  29. Proposed Options for PFRS/FFRS Requirements This percentage is open to discussion Option IV • Publish100% of calculated minimum PFRS and target FFRS requirement, and FFRS to PFRS equivalency ratio by December 1st, for each month of upcoming year • Perform monthly adjustments if needed and post it to MIS by 20th of each month for the upcoming month • Perform day-ahead adjustments and post it to MIS by 6 am for the next operating day • Annual, Monthly and Day-Ahead posting will include requirements and equivalency ratio between FFRS and PFRS, for each 4-hour block of the operating day

  30. Options IV for PFRS and FFRS Requirements • Publish the requirement using 100% of the need Month-Ahead • Month-Ahead/Day-Ahead : determine incremental need AS Requirement Time Real Time Needs 100% of Year-Ahead Month-Ahead Day-Ahead

  31. Proposed Options for PFRS/FFRS Requirements This percentage is open to discussion Option V • Publish 100% of calculated minimum PFRS and target FFRS requirement, and FFRS to PFRS equivalency ratio by December 1st, for each month of upcoming year • Perform day-ahead adjustments and post it to MIS by 6 am for the next operating day • Annual and Day-Ahead posting will include requirements and equivalency ratio between FFRS and PFRS, for each 4-hour block of the operating day

  32. Options V for PFRS and FFRS Requirements • Publish the requirement using 100% of the need annually • Day-Ahead : determine incremental need AS Requirement Time Real Time Needs 100% of Year-Ahead Day-Ahead

  33. Proposed Options for PFRS/FFRS Requirements Option VI • Publish 100% of calculated minimum PFRS and target FFRS requirement by 20th each month for upcoming month based on the worst system condition in previous 2 years • No planned Day-Ahead Adjustment

  34. Other Services • Similar to PFRS and FFRS, Regulation , CRS and SRS requirements can be published day-ahead, monthly or annually

  35. Policy Decisions

  36. Discuss Specific Policy Cuts • Luminant • ERCOT Steel Companies • Energy Storage Association • Co-operative Segment • Summarize Specific Policy Cuts for TAC consideration at the 8-28-14 TAC meeting

  37. Cost/Benefit Assessment Status

  38. Update on RFP for CBA • Met with Segment Representatives on 8-20-14 and discussed the draft “High Level Description of the Cost Benefit Analysis of the Future Ancillary Service Framework” • ERCOT to revise the document and include more language on deliverables expected from the Contractor. • Plan to send out revised document to the group for their review after the 8-28-14 TAC meeting. • The new target is to send out the RFP soon after the 8-28-14 TAC meeting • Draft timeline indicates that a Contractor could possibly start in November and the final report and presentations could possibly be expected in February

  39. Synchronous Inertia Response Service

  40. Synchronous Inertial Response • SIR is stored kinetic energy that is extracted from the rotating mass of synchronous machines following a disturbance in a power system • SIR is not included in the proposed future AS framework and the draft NPRR.

  41. Synchronous Inertial Response • SIR can be provided by synchronous machines, whenever in operation. • Quantity of inertia contribution is determined as kinetic energy that can be provided by a synchronous machine during system imbalance: 2·H·MVA where H is machine inertia constant in seconds, MVA is machine’s rated power • SIR is based on actual physical characteristics of a machine • SIR is independent of machine’s operating point.

  42. SIR Need • Maintain minimum Rate of Change of Frequency (RoCoF) • Provide sufficient time from Point A to Point C, for the Ancillary Services to respond. • With increasing use of non-synchronous generation, changing load characteristics, increase in Combined Cycle units (lower inertia), the system SIR is reduced. • As a result, RoCoF increases, leaving less time for primary frequency response to deploy and arrest the system frequency excursion.

  43. SIR, Current Conditions Case A: Highest Wind Penetration Case Case B: Highest Wind MW Case Case C: Lowest Inertia Case

  44. Synchronous Inertia (June 2013 - May 2014) Inertia=2*Kinetic Energy=2*H*MVA

  45. SIR, Summary and Future Work • To date, RoCoF at HWLL conditions during frequency events is around 0.2 Hz/s and the average time to reach frequency nadir is 4-6 seconds. • Analysis based on Jan-May 2014 system conditions indicated RoCoF of 0.65 Hz/s for two largest unit trip • SIR available under current operating conditions is still sufficient. • SIR will not be introduced as a new AS yet. • ERCOT started to monitor SIR in real-time since July 2014. • ERCOT will continue to analyze the need of SIR and value of emulated inertia* response from non-synchronous generation resources. * Emulated Inertia Response is super-fast (20ms), short duration (8 - 20 s) active power injection in response to frequency decrease below pre-set threshold

  46. Case Study: EIR & PFR from Wind Generation Resources • ERCOT in collaboration with EPRI is conducting studies to verify value of wind generation resources providing EIR and/or PFR and associated uncertainty in the day ahead • Two types of studies: • Dynamic studies: • EIR&PFR uncertainty: comparing Day Ahead wind power production forecast vs actual wind power production, DA wind turbine availability vs Real Time turbine availability and how that impacts EIR and/or PFR that wind generation resources can offer in the DA and deliver in RT. • The results of these studies are expected by the end of this year

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