1. ERCOT Emergency Interruptible Load Service EILS Technical Workshop Commissioners Hearing Room, PUC July 17, 2009

2. 2 2 EILS Technical WorkshopJuly 17, 2009 Antitrust Admonition

3. 3 3 EILS Technical WorkshopJuly 17, 2009 Today’s Agenda (times are approximate) 9:00 AMAntitrust Admonition 9:05 AMEILS General Overview 9:30 AMBaseline discussion 10:30 AMBreak 10:40 AM Updates to procurement process & EILS Resource Submission form NoonLunch 1:00 PM Updates to procurement process & EILS Resource Submission form 2:00 PMScheduled Unavailability discussion 2:45 PMNon-TDSP meter data submission 3:15 PM Review procurement schedule for Oct. 2009- Jan. 2010 Contract Period 3:30 PMAdjourn

4. 4 4 EILS Technical WorkshopJuly 17, 2009 Emergency Interruptible Load Service What EILS is: Service provided by loads (customers) willing to interrupt during an electric grid emergency in exchange for a payment –“Controlled interruption of prepared customers vs. uncontrolled interruption of unprepared customers” An additional tool for ERCOT Operations, deployed only in the late stages of a grid emergency –Last resort prior to firm load shedding (rotating outages) ‘Another tool for the operator toolbox’

5. 5 5 EILS Technical WorkshopJuly 17, 2009 When EILS may be needed When emergencies can occur: –Cold weather months (due to natural gas curtailment & higher forced outages) –Shoulder months (due to unforeseen weather events & large amounts of scheduled maintenance) –Traditional summer peaks –Anytime, as may be caused by: generation outages (scheduled, forced or both) transmission outages beyond likely contingencies extreme weather events multiple simultaneous contingencies EILS may be more likely to be needed in off-peak hours or shoulder months than during traditional summer peaks

6. 6 6 EILS Technical WorkshopJuly 17, 2009 Emergency Operations Event/ActionTrigger ADVISORY: Notice to Market Participants Physical responsive below 3000 MW WATCH: Start Reliability Must Run units, suspend unit testing, deploy Replacement & Non-spin Reserves Physical responsive below 2500 MW Energy Emergency Alert Level 1: Dispatch all generation, issue public media appeal, acquire maximum power thru DC Ties Physical responsive below 2300 MW Level 2A: Deploy LaaRs Physical responsive below 1750 MW Level 2B: Deploy EILS Resources Maintain frequency at 60 Hz Level 3: Instruct transmission owners to shed firm load Frequency below 59.8 hz QSEs should have ample warning of tight conditions before EILS deployments. ERCOT Operators have flexibility to skip Level 2B if frequency is decaying rapidly. In these cases EILS would be deployed immediately after Level 3 to enable faster recovery.

7. 7 7 EILS Technical WorkshopJuly 17, 2009 Dispatch ERCOT Operations orders an EILS deployment via a phone call to the all-QSE hotline 10-minute deployment period begins when QSEs have received the instruction –QSEs’ responsibility to ensure their EILS Resources get the message EILS Resources must deploy within 10 minutes and must keep their committed load off until released ERCOT Operations will release EILS Resources after Responsive Reserves have been restored EILS Resources have 10 hours to return to service after release

8. 8 8 EILS Technical WorkshopJuly 17, 2009 Eligibility: Who can participate? EILS Resources may be individual Loads or aggregations Must have: –15-minute interval metering or statistically valid sample approved by ERCOT –Capability of interrupting at least 1 MW of load on 10 minutes notice at any time during the committed hours –Representation by a Qualified Scheduling Entity (QSE) with a wide-area network agreement with ERCOT Must have 24/7 operations that can receive the verbal dispatch instruction QSE (not ERCOT) is responsible for notifying the customer

9. 9 9 EILS Technical WorkshopJuly 17, 2009 How EILS Works QSEs representing selected EILS Resources are paid a capacity payment to be available for interruption EILS payments are made regardless of whether there is a deployment –If deployed, participants do not receive any additional payment from ERCOT ERCOT’s only financial relationship is with the QSE –QSE submits bid –If bid is accepted, QSE is paid by ERCOT Payment to the EILS Resource (customer) is a private contractual issue between the customer and the QSE

10. 10 EILS Technical WorkshopJuly 17, 2009 Contract Periods & Time Periods EILS is procured for 4-month Contract Periods –February thru May –June thru September –October thru January Participants may bid to provide the service for one or more Time Periods: 1.Business Hours 1: 8 AM to 1 PM Monday-Friday* 2.Business Hours 2: 1 PM to 4 PM Monday-Friday* 3.Business Hours 3: 4 PM to 8 PM Monday-Friday* * Except ERCOT Holidays 4.Non-Business Hours: All other hours Time Periods are designed to allow flexibility in for customers during traditional business hours

11. 11 EILS Technical WorkshopJuly 17, 2009 Procurement Step 1: Resource Identification Submission QSEs identify and submit potential EILS Resources to ERCOT ERCOT staff reviews the prospective EILS Resource’s historical load data (ideally 12 months or more) ERCOT returns the results of its data evaluation back to the QSE as a service to help avoid over- or under-bidding of capacity ERCOT makes baseline assignments Step 2: Bid Submission QSEs submit Bids on behalf of EILS Resources –$ per MW per Hour –Fractional bids above the 1 MW minimum are accepted to tenths of a MW Bidders also must declare Minimum Base Load –Minimum Base Load is the “drop-to” target for EILS Resources on the Alternate Baseline

12. 12 EILS Technical WorkshopJuly 17, 2009 Procurement & payment ERCOT management selects EILS providers based on submitted QSE bids ‘Reasonableness’ criteria and limits may be applied to stay under the PUC’s cost cap of $50 million per year –See document posted at the EILS web page Participants are paid as bid if ERCOT accepts their offer –No clearing price mechanism Payments are made to QSEs ≤70 days after the end of the Contract Period Payments will be adjusted if the EILS Resource fails to perform in either of two ways: 1.Availability: Load must be online and available for interruption during the contracted hours 2.Performance: Load must meet its curtailment obligations if ERCOT dispatches EILS in an emergency

13. Baselines

14. 14 EILS Technical WorkshopJuly 17, 2009 Baselines EILS Baselines are assigned by ERCOT based on interval meter data evaluation Default Baseline: –‘Drop-by’ requirement –Three default baseline types: Statistical Regression Model Middle-8-of-10 Preceding Like Days Matching Day Pair Alternate Baseline –‘Drop-to’ requirement (not really a baseline per se) –Designed for highly variable loads; allows participation by loads that cannot be modeled accurately –Open to all participants if they so choose

15. 15 EILS Technical WorkshopJuly 17, 2009 Default Baselines Default baseline is a statistical estimation of what a load would have done in the absence of a deployment For each ESI ID (individual load or part of an aggregation), ERCOT determines whether one or more of the 3 default baseline types are applicable If ERCOT deems the adjusted load estimates produced by a default baseline model are sufficiently accurate and reliable, the estimates generated for an EILS event day will comprise the baseline Baseline loads (individually or in aggregate) are compared to actual loads on the event day to assess performance by the EILS Resource –Interval performance factors are calculated by comparing actual load to the baseline for each 15-minute interval –Event Performance Factor is the average of all interval performance factors

16. 16 EILS Technical WorkshopJuly 17, 2009 Default Baseline concept Metered Load TIME MW Baseline 1 MW Contracted Load Reduction 10-minute reduction deadline Release Deployment instruction Normal operations (max 10 hours) 98765432109876543210

17. 17 EILS Technical WorkshopJuly 17, 2009 Default Baseline types: Regression Model Rationale: Load can be predicted using weather and calendar variables Creates a baseline through regression analysis using numerous inputs: –Historical interval meter data – going back at least 12 months, longer if necessary and available –Interval meter data collected during the Contract Period –Weather data –Calendar data –Sunrise/sunset times Same methodology used to create ERCOT’s daily Load Profiles Detailed description of the regression methodology is available under the ‘Forms & Supporting Documents’ tab at: http://www.ercot.com/services/programs/load/eils/ http://www.ercot.com/services/programs/load/eils/

18. 18 EILS Technical WorkshopJuly 17, 2009 Default Baseline types: Middle 8-of-10 Preceding Like Days Rationale: Load on recent days of the same day-type prior to an EILS event is likely to be similar to business-as-usual load for the event day Step 1: Identify the 10 most recent days having the same day-type as the event day. –Day-types are defined as: Weekdays (Monday – Friday excluding holidays) Weekend / Holidays (Saturday, Sunday and ERCOT Holidays) –Discard any day with: Energy Emergency Alert (EEA) events Scheduled unavailability Other apparent outlier load values –After discarding, go back in time until 10 acceptable days are found Step 2: Calculate overall kWh consumption for each of the 10 days and eliminate the days with the highest and lowest usage Step 3: Average the interval loads for the 8 remaining days -- result is the unadjusted baseline

19. 19 EILS Technical WorkshopJuly 17, 2009 Default Baseline types: Matching Day Pair Rationale: Historical matching day-pairs can be found that are similar to load on the day-of and day preceding the event Step 1: Match intervals for the entire day before and the day of the event (up to one hour before the start of the event) with corresponding intervals for all day-pairs of the same type for the preceding year –Day-pair types are classified by event day and are defined as follows: Weekdays (Monday – Friday excluding holidays) Weekend / Holidays (Saturday, Sunday and ERCOT Holidays) –Discard any days with: Energy Emergency Alert (EEA) events Scheduled unavailability Other apparent outlier load values Step 2: Calculate the sum of squared differences across the matching intervals between a matching day-pair and the event day-pair Step 3: Unadjusted baseline = interval-by-interval average of the 10 matching day-pairs with the lowest sum of squared differences

20. 20 EILS Technical WorkshopJuly 17, 2009 Default Baselines: Event-day Adjustment An event-day adjustment is applied to all 3 default baseline types to improve accuracy Adjustment is based on the 8 intervals beginning three hours before the event start time –Load changes occurring in the hour before the event will not affect the adjusted baseline Actual kWh for the adjustment period = the sum of the Load’s actual kWh across the 8 adjustment intervals Baseline kWh = the sum of the baseline estimates across the same 8 intervals Adjustment factor = actual kWh divided by the baseline kWh Adjusted baseline kWh = unadjusted baseline kWh for each event interval x the adjustment factor

21. 21 EILS Technical WorkshopJuly 17, 2009 Alternate Baseline Some loads do not have enough predictability to allow ERCOT to create a default baseline model; for example: –Fluctuating or batch-process loads –Loads with unpredictable downtimes or irregular schedules ERCOT will assign such loads to the Alternate Baseline –A.K.A. “drop to” baseline EILS Resources may choose the Alternate Baseline if they desire –Some Loads prefer the Alternate Baseline (e.g., industrials with high load factors) MW Bids should be ≤ projected average hourly load minus declared Minimum Base Load During an EILS deployment, load must not exceed its declared Minimum Base Load throughout the event

22. 22 EILS Technical WorkshopJuly 17, 2009 Availability Factor Using interval meter data after the fact, ERCOT calculates an Availability Factor for each EILS Resource Availability Factors are specific to baseline assignments: –Default Baseline: Percentage of committed hours that Load was greater than than 95% of committed MW capacity –Alternate Baseline: Average hourly load (minus declared Minimum Base Load) divided by committed MW capacity –Exempted: Any hours an EEA is in effect Scheduled Periods of Unavailability (up to 2% of hours in a Contract Period if noticed 5 Business Days in advance) Any hours an EILS test was being conducted If availability factor drops below 0.95, payment will be reduced If it’s 0.95 or greater, it will be reset to 1.0 Capped at 1.0

23. 23 EILS Technical WorkshopJuly 17, 2009 Performance Factor In a deployment event, EILS Resource must shed its committed load within 10 minutes and keep it off until released Performance will be evaluated by ERCOT using 15-minute interval data via the following calculations: –Interval Performance Factor (number between 0 and 1) = ratio of actual to committed load reduction during each 15-minute interval covered by the event, specific to baseline assignment: Default = baseline minus actual Load, divided by MW bid value, weighted to the fraction of the interval that the curtailment period is in effect Alternate = declared Minimum Base Load divided by actual Load, with separate calculations for partial intervals at the beginning and end of the deployment period –Event Performance Factor = average of the interval performance factors for all intervals of the deployment Event performance factor of ≥0.95 constitutes successful performance for the event

24. 24 EILS Technical WorkshopJuly 17, 2009 Aggregated EILS Resources Aggregations receive baseline assignments (default or alternate) just as individual EILS Resources Aggregations are more likely to qualify for a default baseline than individual loads –Aggregations with larger numbers of loads are more likely to qualify than small aggregations Performance & availability of aggregations are: –Calculated the same as for individual EILS Resources -- according to baseline assignment –Determined at the aggregation level using summed load totals

25. 25 EILS Technical WorkshopJuly 17, 2009 Payment Formula Within 70 days after the end of a Contract Period, QSEs representing EILS Resources are paid as follows, by Time Period: (Bid amount X MW X Hours) X (Availability Factor) Number between 0 and 1 X (Performance Factor) Number between 0 and 1

26. 26 EILS Technical WorkshopJuly 17, 2009 Compliance & Testing Failure to meet availability or performance obligations is a violation of ERCOT Protocols –In addition to payment reduction, EILS Resource and/or its QSE are subject to 6-month suspension from program For aggregated EILS Resources, the entire aggregation is subject to suspension –Also subject to administrative penalties by the Public Utility Commission of Texas EILS Resources are subject to annual unannounced testing –Must deploy in 10 minutes just as in an actual event –Failure will result in re-testing –Two failures in a row subjects the EILS Resource to a 6-month suspension –Substantial change to an EILS Resource during a year may result in an additional test

27. Updates to Procurement Process

28. 28 EILS Technical WorkshopJuly 17, 2009 Updates to Procurement Process Goals –Streamline and automate process to accommodate program growth –Reduce data entry and manipulation errors –Create an interactive process which allows QSEs to reconfigure Resources during the Resource ID phase to achieve a desired baseline –Provide baseline certainty at the Resource ID phase –Avoid redundant baseline analysis during both the Resource ID and Bid Analysis phases –Improve scheduled unavailability process

29. 29 EILS Technical WorkshopJuly 17, 2009 Procurement Updates: Preliminary Baseline Review Purpose : Enable QSEs to obtain unofficial baseline assignments outside the procurement process New form (EILS Resource Submission Form – same for all phases of EILS) –QSE may submit EILS Resources multiple resources in one workbook (one tab per resource) –May submit multiple configurations of ESIIDs and/or Time Periods (baseline assignment options are likely to be influenced by the specific configuration) –ERCOT will provide baseline results in separate workbooks for each submitted Resource –Preliminary Baseline Review phase will be closed during the EILS Resource ID phase

30. 30 EILS Technical WorkshopJuly 17, 2009 Procurement Updates: Resource ID Phase Purpose : Enable QSEs to officially identify and submit potential EILS Resources to ERCOT ERCOT staff reviews prospective EILS Resources and determines baseline assignment eligibility and historical Load availability EILS Resource ID phase extended to approximately four weeks New form (EILS Resource Submission Form – same for all phases of EILS) Interactive process between ERCOT and the QSE –QSE submits form with prospective EILS Resources Multiple Resources per workbook allowed –ERCOT validates inputs for each Resource, exceptions reported back to QSE for potential correction and resubmission –For validated Resources, ERCOT produces one workbook per resource showing: Identification tab and Resource tab as submitted by QSE Baseline eligibility and Load availability ERCOT Assigned unique Resource ID number –Resources may be reconfigured (ESIIDs and/or Time Periods) and resubmitted –Only validated resources with an assigned Resource ID number are allowed to bid Resources submitted on or before 8-20-09 will be eligible for Default baselines Resources submitted from 8-21-09 through 8-26-09 will only be eligible for Alternate baseline

31. 31 EILS Technical WorkshopJuly 17, 2009 Procurement Updates: Bid Phase Purpose: Enable QSEs to officially offer EILS Resources to ERCOT QSE may submit bids only for Resources validated during the Resource ID phase with an assigned number –Uses the new EILS Resource Submission Form (same for all phases of EILS) –Identification fields will be pre-populated by ERCOT –QSEs will enter bid-related inputs to the workbook: MW capacity offer Price Minimum Base Load Baseline selection (if multiple options available) Proration selection –No other changes allowed (e.g. ESIIDs, Time Periods etc.) QSE will submit one form per EILS Resource –Large numbers of files may be Zipped QSEs must ensure that no ESI ID is submitted more than once –Bids with duplicate ESI IDs are subject to rejection by ERCOT

32. 32 EILS Technical WorkshopJuly 17, 2009 EILS Resource Submission Form Review –Open EILS Resource Submission Form examples

33. 33 EILS Technical WorkshopJuly 17, 2009 EILS Resource Submission Form Review Exceptions Tab: –Any errors or warning messages related to data submitted by the QSE will appear on this tab –Errors result in no Resource ID number being assigned – resource will not be eligible for bid submission –Example errors: “ESIID not in Lodestar” “Current Svc history status: I” “Current Svc history status: D” “Sub-meter Data Failed Validation” –Warnings are produced for information purposes, resource will be eligible for bid submission but some QSE action may be required –Example warnings: “Currently NIDR meterdata type” “NonLS Intervaldata with no matching Input Unique_Meter_Id” “Missing NonLS Intervaldata” “IDR servhist starts 29JAN2009 which is 394 days after begin of review period”

34. 34 EILS Technical WorkshopJuly 17, 2009 EILS Resource Submission Form Review Availability Results Tab: –Tab is the same as in previous contract periods Exception: Minimum base Load will no longer be input for the Resource ID Phase Minimum base Load has no impact on eligible baseline assignments –Results based on most recent 12 months of historical load data –Available Capacity in MW is reported for Resources eligible for Default Baseline – value reported is 95th percentile Load level –Average Load in MW is reported for all Resources Resources ineligible for a Default Baseline only receive this value Resources eligible for a Default Baseline also receive this value (they may opt for an alternate baseline) –QSEs should carefully consider baseline assignment for a resource when determining bid and minimum base Load amounts

35. 35 EILS Technical WorkshopJuly 17, 2009 EILS Resource Submission Form Review Baseline Information Tab: –This tab contains diagnostic statistics to assist QSE with default baseline assignment selection and MW bid determination Results for all acceptable default baseline options are shown Results for any other default baselines are omitted If only the Alternate Baseline is available for a Resource, no results are shown –Statistics provided: RSquare: The percent of variation in actual load that is explained by variation in the baseline load. (100% indicates a perfect baseline) MAPE: Mean Absolute Percent Error—Average absolute difference between the actual load and the baseline estimate PXX_kW_Confidence: (XX = 90, 95, 99) Based on historical data, the kW amount by which a QSE may consider de-rating an offer to achieve a XX% probability of meeting event performance requirements

36. 36 EILS Technical WorkshopJuly 17, 2009 Scheduled Unavailability Open Scheduled Unavailability form

37. 37 EILS Technical WorkshopJuly 17, 2009 Scheduled Unavailability Reports will be provided to QSE for all unavailability notices received by ERCOT –Status of 2% exclusion –Exceptions Possible exceptions: –Not all ESIIDs in Resource entered on form –ESIID/Unique Meter ID not participating in current contract period –Invalid dates and times, for example: Stop date before start date Invalid date or time New submissions or cancellations with missing start or stop dates and times Revisions with missing start, stop,revised start or revised stop dates and times –Revisions or Cancellations without matching New Submissions –Overlapping New Submissions without an intervening revision or cancellation –Insufficient notice for unavailability 5 Business days required for New Submission, and Revisions (adding periods of unavailability) –Otherwise, not eligible for the 2% exclusion but will not be used for default baseline calculations 1 Business day required for Cancellations & Revisions (deleting periods of unavailability) –Otherwise, period will be treated as unavailable and will be counted towards 2% exclusion allowance for the Resource

38. 38 EILS Technical WorkshopJuly 17, 2009 38 Non-ERCOT Interval Data QSEs have the option to arrange for 15-minute interval kWh data to be collected and provided to ERCOT –Sub-metering a specific Load within a facility –Premise level metering for NIDR customers –Premise level metering for participants in Non Opt-in Entity areas Interval Data File Format Description http://www.ercot.com/content/services/programs/load/eils/keydocs/Interv al%20Data%20File%20Format%20Description.doc IDR Data Format Example http://www.ercot.com/content/services/programs/load/eils/keydocs/IDR%2 0Data%20Format%20Example.csv

39. 39 EILS Technical WorkshopJuly 17, 2009 39 Non-ERCOT Interval Data (continued) Timing for submitting interval data –Must accompany EILS Resource Submission form for either Preliminary Baseline Review or Resource ID 12 to 24 months of data needed if a default baseline assignment is desired No affidavit required –For Contract Performance, deadline for submitting 35 days after end of Contract Period Affidavit required at time of submission Data Validation –Unique Meter ID (UMI) in interval data file must match the UMI provided on the EILS Resource Submission Form –Interval data will be checked for: Gaps and duplicate days Correct number of intervals per day including DST days Comparability with ERCOT monthly NIDR (kWh and kW values) if applicable Comparability with ERCOT IDR interval settlement data –Missing data and unresolved discrepancies will be treated as zeros for contract performance

40. 40 EILS Technical WorkshopJuly 17, 2009 References & Additional Information EILS page at ERCOT.com –http://www.ercot.com/services/programs/load/eils/index.htmlhttp://www.ercot.com/services/programs/load/eils/index.html –Includes: Technical Requirements & Scope of Work Reports of procurement results from previous Contract Periods Forms and other supporting documents Description of factors used in determining reasonableness of bids Annual report to the Public Utility Commission PUC Substantive Rule § 25.507 –http://www.puc.state.tx.us/rules/subrules/electric/25.507/25.507ei.cfmhttp://www.puc.state.tx.us/rules/subrules/electric/25.507/25.507ei.cfm ERCOT Protocols –http://www.ercot.com/mktrules/protocols/currenthttp://www.ercot.com/mktrules/protocols/current

41. 41 EILS Technical WorkshopJuly 17, 2009 Contacts Questions should be submitted to EILS@ercot.comEILS@ercot.com EILS contacts at ERCOT: –Paul Wattles, pwattles@ercot.compwattles@ercot.com –Steve Krein, skrein@ercot.comskrein@ercot.com –Thelma Garza, tgarza@ercot.comtgarza@ercot.com –Carl Raish, craish@ercot.comcraish@ercot.com –Diana Ott, dott@ercot.comdott@ercot.com Market Participants may also contact their Client Services account manager

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