Three Decimals for Profile Resolution

2 Pro Case for Three Decimals for Profile Resolution  Generation 15 minute pattern rarely has 2 adjacent equal intervals.  Rounding to 2 decimals is not supported by any specific rule.  Residential load is not flat for 1.5 hours at aggregate level.  Rounding to 1 decimal shows a pattern even less like generation.  Rounding to 3 decimals would be a pattern closer generation pattern.  Small profile numbers in 15 minute intervals are being used to settle large volumes of MWh.  Significant settlement dollars can be affected by the difference of two vs. three decimals as seen from ERCOT presentation in interval 43 (by eye) looks like 30 MW difference which at a future possible $3,000 MCPE would be $90,000.  Per ERCOT, small mean populations are affected by rounding.  Cost to implement is nil.

3 No two adjacent intervals exactly equal

4 PWG Presentations RESLOWR ALL LRS.ppt page 8

5 RESLOWR_NORTH5/22/2007 with two decimals Current Market Condition RESLOWR_NORTH5/22/2007

6 Optional Content Slide for Executive Presentations

7 January 27, 2006 Residential Load Comparison (from ERCOT presentation) Potential $90,000 interval settlement

8 From ERCOT Presentation In large Round 2 Sample strata Precision shall be lower Small means are affected by rounding

9 Reference links for data sources  page 13 in key document called “2 vs 3 decimals”. vs 3 decimals  ml for generation load from key document “ Initial Market Totals”. ml Initial Market Totals  for profile load

10 Recommendation COPS Motion to change profile rounding to three decimals