-- Transition to New Load Profiles --What to Post?

COPS

December 11, 2006

2

Introduction

• New Load Profile models anticipated to be implemented on May 15, 2007.

• Profile transition plan Option 3M allows for a mixture of old and new profiles to be used in settlement.

• On 12/07/06, DEWG conference call discussed numerous options for posting profiles to ERCOT.com and TML (see Appendix)

3

Forecasted Load Profiles

DEWG consensus was to:

Post forecasted load profiles generated only from new models from May 15th onward.

So what would be in the files posted on ERCOT.com and the TML?

4

Forecasted Load Profiles

A look at ERCOT.com on May 17, 2007(New models anticipated to be implemented for May 15, 2007)

Backcasted (Auxiliary) Load Profiles

20070517.043834.FcstPrfl05172007.csv20070516.043850.FcstPrfl05162007.csv20070515.043753.FcstPrfl05152007.csv20070514.043729.FcstPrfl05142007.csv20070513.043846.FcstPrfl05132007.csv20070512.043833.FcstPrfl05122007.csv

Forecasts for May 17, 18, 19, 20 from NEW models Forecasts for May 16, 17, 18, 19 from NEW models Forecasts for May 15, 16, 17, 18 from NEW models Forecasts for May 14 from OLD models, 15, 16, 17 from NEW Forecasts for May 13, 14 from OLD models, 15, 16 from NEW Forecasts for May 12, 13, 14 from OLD models, 15 from NEW

Files on the TML would also be as shown.

5

Backcasted Load Profiles

DEWG consensus was:

For trade date 05/15/07 onward, to post profiles generated from new models in ‘primary’ folder and profiles from old models in ‘auxiliary’ folder.

So what would be in the files posted on ERCOT.com and the TML?

Profiles from old models would be posted in auxiliary folder for 90 days and archived on ERCOT.com afterward.

Backcasted (Auxiliary) Load Profiles

Auxiliary profiles posted here. Similar folder on TML. File names would be followed by “_aux”.

6

Backcasted Load Profiles

20070517.154703.BcstPrfl05162007.csv20070516.154651.BcstPrfl05152007.csv20070515.154706.BcstPrfl05142007.csv20070514.154727.BcstPrfl05132007.csv20070513.154810.BcstPrfl05122007.csv20070512.154759.BcstPrfl05112007.csv

Backcast for trade date 05/16/07, from NEW models Backcast for trade date 05/15/07, from NEW models Backcast for trade date 05/14/07, from OLD models Backcast for trade date 05/13/07, from OLD models Backcast for trade date 05/12/07, from OLD models Backcast for trade date 05/11/07, from OLD models

A look at ERCOT.com on May 17, 2007(New models anticipated to be implemented for May 15, 2007)

Backcasted (Auxiliary) Load Profiles

Primary

Files on the TML would also be as shown.

7

Backcasted Load Profiles

Backcasted (Auxiliary) Load Profiles

Backcast for trade date 05/16/07, from OLD models Backcast for trade date 05/15/07, from OLD models Backcast for trade date 05/14/07, from NEW models Backcast for trade date 05/13/07, from NEW models Backcast for trade date 05/12/07, from NEW models Backcast for trade date 05/11/07, from NEW models

20070517.154708.BcstPrfl05162007_aux.csv20070516.154657.BcstPrfl05152007_aux.csv20070515.154713.BcstPrfl05142007_aux.csv20070514.154731.BcstPrfl05132007_aux.csv20070513.154816.BcstPrfl05122007_aux.csv20070512.154807.BcstPrfl05112007_aux.csv

(Auxiliary)

A look at ERCOT.com on May 17, 2007(New models anticipated to be implemented for May 15, 2007)

Auxiliary

Files on the TML would also be as shown.

8

Questions or

Comments

9

Appendix

Options Considered by DEWG

-- Transition to New Load Profiles --What to Post?

DEWG

December 7, 2006

11

Introduction

• New Load Profile models anticipated to be implemented on May 15, 2007.

• Profile transition plan Option 3M allows for a mixture of old and new profiles to be used in settlement.

• How should both old and new load profiles be posted to ERCOT.com and the TML?

In this presentation:

“Primary” profiles refer to those generated using the old models for trade dates thru May 14th, and for profiles generated using the new models for trade dates on or after May 15th.

“Auxiliary” profiles refer to converse of the “primary” profiles.A2

12

Forecasted Load Profiles

Option F4: Post only new profiles starting May 15th

Option F1: Post old and new profiles in separate folders

May 12th posting would contain new profiles for May 15th, and so on...

Profiles from old models would be posted in separate (auxiliary) folder for 60 days.

Forecasted (Auxiliary) Load Profiles

Auxiliary profiles posted here. Similar folder on TML. File names would be same as primary load profiles.

Option F3: Post old and new profiles with channel numbersProfiles would be posted in a single file. Channel placement options on next slide.

Option F2: Post old and new profiles w/ different file names

20061206.043850.FcstPrfl12062006_1.csv20061206.043849.FcstPrfl12062006_2.csv Channel number

(in same folder)

A3

13

Forecasted Load Profiles

Option F3: Post old and new profiles with channel numbers

Option F3a

Option F3b

Option F3c

channel number as part of Profile Type and Weather Zone combo

channel number in new field

channel number at end of row

Channel ‘1’ would refer to the primary profiles and channel ‘2’ would refer to the auxiliary profiles.

A4

14

Backcasted Load Profiles

Option B1: Post old and new profiles in separate foldersProfiles from old models would be posted in separate (auxiliary) folder for 60 days and archived on ERCOT.com afterward.

Backcasted (Auxiliary) Load Profiles

Auxiliary profiles posted here. Similar folder on TML. File names would be same as primary load profiles.

Option B3: Post old and new profiles with channel numbersChannel ‘1’ would refer to the primary profiles and channel ‘2’ would refer to the auxiliary profiles. Channel placement options on next slide.

Option B2: Post old and new profiles w/ different file names

20061205.154658.BcstPrfl12042006_1.csv20061205.154657.BcstPrfl12042006_2.csv

(in same folder)

Channel number

A5

15

Backcasted Load Profiles

Option B3: Post old and new profiles with channel numbers

Option B3a

Option B3b

Option B3c

channel number as part of Profile Type and Weather Zone combo

channel number in new field

channel number at end of row

Channel ‘1’ would refer to the primary profiles and channel ‘2’ would refer to the auxiliary profiles.

A6

16

ForecastsOption F1

Option F2

Option F3a

Option F3b

Option F3c

Option F4

Making a Choice

BackcastsOption B1

Option B2

Option B3a

Option B3b

Option B3c

A7

17

Questions or

Comments

A8