Three Decimals for Profile Resolution

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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.

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No two adjacent intervals exactly equal

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PWG Presentations RESLOWR ALL LRS.ppt page 8

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RESLOWR_NORTH 5/22/2007 with two decimalsCurrent Market Condition

RESLOWR_NORTH 5/22/2007

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Optional Content Slide for Executive Presentations

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January 27, 2006 Residential Load Comparison (from ERCOT presentation)

Potential $90,000 interval settlement

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From ERCOT PresentationIn large Round 2 Sample strata Precision shall be lower

Small means are affected by rounding

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Reference links for data sources

http://www.ercot.com/calendar/2007/05/20070522-PWG.html page 13 in key document called “2 vs 3 decimals”.

http://www.ercot.com/mktinfo/settlements/markettotals/initial/index.html for generation load from key document “2007-05 Initial Market Totals”.

https://pi.ercot.com/contentproxy/publicList?folder_id=10001721 for profile load

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Recommendation

COPS Motion

to change profile rounding to three decimals