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Residential Annual Validation Suspension Update. Presented by ERCOT Staff to Profiling Working Group 09/29/2005. Residential Survey Update. Survey was mailed on August 30, 2005 Response rate is 11.0% as of 09/16/2005 (about the same as the pilot survey)
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Residential Annual Validation Suspension Update Presented by ERCOT Staff to Profiling Working Group 09/29/2005
Residential Survey Update • Survey was mailed on August 30, 2005 • Response rate is 11.0% as of 09/16/2005 (about the same as the pilot survey) • Response data is being provided by the Market Research firm • Next steps • Response validation • Statistical Assignment Algorithm development • Apply algorithm to all ESIIDS with Profile Assignment Changes and determine accuracy • Algorithm will also be applied to evaluate overall assignment accuracy and the accuracy impact of proposed changes for Annual Validation 2006
Data Aggregation Test Runs • Test environment has been created and snapshot of Production Lodestar taken as of 07/30/2005 • Stratified Sample of 30 trade days has been selected • 3 Strata based on difference between RESLOWR and RESHIWR profile • 10 days per stratum • Baseline Data Aggregation Runs have been completed and statistics captured • Profile IDs have been updated (old ones saved to a temporary table to allow us to revert back to original assignments) to reflect Annual Validation • 578,000 Residential Assignment changes • Next steps • Data Aggregation Re-Runs to capture the affect to the assignment changes • Analyze and summarize differences • Will revert assignments to allow for testing of revised assignment algorithm(s) • Will perform similar analysis on Business to obtain Annual Validation impacts for Residential only, Business only and Both
Statistical Assignment Algorithm • Regression between actual meter readings for a premise and the RESHIWR and RESLOWR profile consumption for the same time periods • Use reads during shoulder and winter months for several years • Assign to profile with a better fit • Omit reads during periods of very low use (no/low occupancy) • Omit outlier reads and require some reads to exceed a minimum kWh/day threshold in order to assign RESHIWR • Parameters of assignment process determined from use of Residential Survey response data
IMPACT OF PROFILE ASSIGNMENT MISCLASSIFICATION • PROFILE ASSIGNMENT ERRORS CREATE TWO TYPES OF LOAD PROFILE ESTIMATION DIFFERENCES • ASSIGNMENT OF BILLING KWH TO THE DAYS WITHIN THE BILLING PERIOD • (RESHIWR assigns more kWh than RESLOWR to cold days) • ASSIGNMENT OF DAILY KWH TO THE INTERVALS WITHIN THE DAY • (RESHIWR assigns more kWh to morning intervals)
COAST HI/LO RATIO INTERVAL PERCENT OF MONTHLY KWH OCT 2004 – APR 2005 50% of intervals have > 15% difference
EAST HI/LO RATIO INTERVAL PERCENT OF MONTHLY KWH OCT 2004 – APR 2005 50% of intervals have > 15% difference
FWEST HI/LO RATIO INTERVAL PERCENT OF MONTHLY KWH OCT 2004 – APR 2005 51% of intervals have > 15% difference
NCENT HI/LO RATIO INTERVAL PERCENT OF MONTHLY KWH OCT 2004 – APR 2005 50% of intervals have > 15% difference
NORTH HI/LO RATIO INTERVAL PERCENT OF MONTHLY KWH OCT 2004 – APR 2005 50% of intervals have > 15% difference
SCENT HI/LO RATIO INTERVAL PERCENT OF MONTHLY KWH OCT 2004 – APR 2005 40% of intervals have > 15% difference
SOUTH HI/LO RATIO INTERVAL PERCENT OF MONTHLY KWH OCT 2004 – APR 2005 46% of intervals have > 15% difference
WEST HI/LO RATIO INTERVAL PERCENT OF MONTHLY KWH OCT 2004 – APR 2005 49% of intervals have > 15% difference
BUSINESS LOAD FACTOR DYNAMIC ASSIGNMENT ISSUES Presented by ERCOT Staff to Profiling Working Group 09/29/2005
BUSINESS LOAD FACTOR DYNAMIC ASSIGNMENT ISSUES • Load Factor is calculated for assignment year (e.g. May 2004 – April 2005) • Transactions to change Profile Type are submitted in October and applied for next 12 months • Year-to-year, season-to-season and month-to-month Load Factors can be out of sync with actual use • For example, a high Load Factor monthly read can be settled with a low Load Factor Profile
PROFILE ID ASSIGNMENT LAGESIID PROFILE TYPES OUT OF PHASE Because of the assignment lag, we discover during Annual Validation that, for some ESIIDs, the previous assignment is inconsistent with actual use during the year for which the previous assignment was used in settlement
MONTHLY READS AND ANNUAL USE BYASSIGNED PROFILE TYPE VS MONTHLY LOAD FACTOR ERCOT receives monthly kWh and kW reads from TDSPs indicate a monthly load factor … these can be inconsistent with the Profile Assignment
PERCENT OF ESIIDs WITH"MISS-PROFILED" READS The majority of ESIIDs have one or more monthly reads which are inconsistent with the Profile Assignment