Oil & Gas Final Sample Analysis April 27, 2006. 2 Background Information TXU ED provided a list of ESI IDs with SIC codes indicating Oil & Gas (8,583)

Oil & GasFinal Sample Analysis

April 27, 2006

2

Background Information• TXU ED provided a list of ESI IDs with SIC codes indicating Oil & Gas (8,583)

• These were mapped into LRS sample cells– 421 LRS sample points were identified as Oil & Gas– 15 LRS sample cells identified with significant population counts having no sample

points available– Requestor agreed to fund IDR installation/data collection for ERCOT selected

sample points in those cells (data collected for March – May 2005)

• TXU ED performed field verification on all Oil & Gas sample points

• 7,342 ESI IDs were included in this preliminary analysis covering the March – May time period

• ESI IDs included in analysis based on– Active during the analysis period– Complete NIDR usage available– Profile Group was BUSNODEM, BUSLOLF, BUSMEDLF, BUSHILF– Belong to a cell with LRS interval data available for one or more ESI IDs

• Sample data was scanned to verify that usage patterns were likely to be Oil & Gas (none were considered miss-classified)

3

Oil & Gas Sample Size by Stratum

Population Size: 7,342

Sample Size: 412

Strata: 76 out of 104

Profile Group

Wzone VoltageStratum

#Sample

SizePopulation

SizeProfile Group Wzone Voltage

Stratum #

Sample Size

Population Size

BUSHILF EAST PRI 1 3 4 BUSMEDLF EAST PRI 55 1 1BUSHILF EAST SEC 2 1 23 BUSMEDLF EAST SEC 56 1 21BUSHILF FWEST PRI 4 44 728 BUSMEDLF FWEST PRI 59 65 914BUSHILF FWEST PRI 5 6 143 BUSMEDLF FWEST PRI 60 18 206BUSHILF FWEST PRI 6 4 46 BUSMEDLF FWEST PRI 61 13 55BUSHILF FWEST SEC 7 1 86 BUSMEDLF FWEST PRI 62 2 2BUSHILF FWEST SEC 8 2 9 BUSMEDLF FWEST SEC 63 2 326BUSHILF NCENT PRI 9 3 53 BUSMEDLF FWEST SEC 64 1 8BUSHILF NCENT SEC 11 1 66 BUSMEDLF FWEST SEC 65 1 3BUSHILF NORTH PRI 13 9 141 BUSMEDLF NCENT PRI 66 9 55BUSHILF NORTH PRI 14 6 39 BUSMEDLF NCENT SEC 67 1 172BUSHILF NORTH PRI 15 5 8 BUSMEDLF NORTH PRI 69 6 113BUSHILF NORTH SEC 16 1 119 BUSMEDLF NORTH PRI 70 8 28BUSHILF WEST PRI 19 3 53 BUSMEDLF NORTH PRI 71 2 7BUSHILF WEST PRI 20 4 11 BUSMEDLF NORTH PRI 72 3 3BUSHILF WEST PRI 21 4 4 BUSMEDLF NORTH SEC 73 1 93BUSHILF WEST PRI 22 2 2 BUSMEDLF WEST PRI 77 6 81BUSHILF WEST SEC 23 1 8 BUSMEDLF WEST PRI 78 5 18

BUSMEDLF WEST PRI 79 4 7BUSLOLF EAST PRI 24 2 2 BUSMEDLF WEST PRI 80 2 3BUSLOLF EAST SEC 25 1 33 BUSMEDLF WEST SEC 81 1 22BUSLOLF FWEST PRI 28 43 653BUSLOLF FWEST PRI 29 15 172 BUSNODEM EAST SEC 83 1 76BUSLOLF FWEST PRI 30 15 52 BUSNODEM FWEST PRI 86 10 10BUSLOLF FWEST PRI 31 2 2 BUSNODEM FWEST SEC 87 1 201BUSLOLF FWEST SEC 32 1 140 BUSNODEM FWEST SEC 88 1 86BUSLOLF FWEST SEC 33 1 31 BUSNODEM FWEST SEC 89 2 83BUSLOLF NCENT PRI 35 5 28 BUSNODEM NCENT PRI 90 1 1BUSLOLF NCENT SEC 37 1 92 BUSNODEM NCENT SEC 91 3 741BUSLOLF NORTH PRI 40 7 71 BUSNODEM NCENT SEC 92 1 185BUSLOLF NORTH PRI 41 5 21 BUSNODEM NCENT SEC 93 2 174BUSLOLF NORTH PRI 42 4 7 BUSNODEM NORTH PRI 94 4 4BUSLOLF NORTH PRI 43 2 2 BUSNODEM NORTH SEC 95 1 196BUSLOLF NORTH SEC 44 1 87 BUSNODEM NORTH SEC 96 1 130BUSLOLF WEST PRI 48 7 35 BUSNODEM NORTH SEC 97 1 146BUSLOLF WEST PRI 49 6 20 BUSNODEM SCENT SEC 98 1 61BUSLOLF WEST PRI 50 5 9 BUSNODEM WEST PRI 101 1 1BUSLOLF WEST PRI 51 3 3 BUSNODEM WEST SEC 102 1 55

BUSNODEM WEST SEC 103 1 28BUSNODEM WEST SEC 104 1 23

4

Oil & Gas Sample Size by Stratum

• For statistical analysis purposes original sample strata were consolidated into 22 analysis strata

• Minimum of 5 sample points per analysis stratum

• Strata were consolidated based on the same or similar case weights(Case weight = sample size/population size)

5

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0.18

0.20

0.22

0.24

0.26

Mar 01 Mar 08 Mar 15 Mar 22 Mar 29 Apr 05 Apr 12 Apr 19 Apr 26 May 03 May 10 May 17 May 24 May 31

Unknow n

Local Time

M arch - June

Example: BUSNODEM ESI ID March 1 – May 31

kWh

6

Example: BUSNODEM ESI ID March 1 – May 31

7

Example: BUSLOLF ESI ID March 1 – May 31

8


kWh

kWh

9


0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

2.6

2.8


Unknow n

Local Time

M arch - June

kWh

10

Example: BUSMEDLF ESI ID March 1 – May 31

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8


Unknow n

Local Time

M arch - June

kWh

11


0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4

1.5


Unknow n

Local Time

M arch - June

kWh

12


0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

2.6

2.8


Unknow n

Local Time

M arch - June

kWh

13

Example: BUSHILF ESI ID March 1 – May 31

0.1

0.2

0.3

0.4

0.5

0.6


Unknow n

Local Time

M arch - June

kWh

14

Example: BUSHILF ESI ID March 1 – May 31

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1


Unknow n

Local Time

M arch - June

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

Tue 01 Wed 02 Thu 03 Fri 04 Sat 05 Sun 06 Mon 07 Tue 08

Unknow n

Local Time

M arch 2005

kWh

kWh

15

90% Confidence

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

<= 4 4 - 5 5 - 6 6 - 7 7 - 8 8 - 9 9 - 10 10 - 11 > 11

Percent Accuracy

Inte

rva

l Co

un

t

Distribution of Sample PrecisionDistribution of Sample Precision

Mean 6.4%

Precision for 93% of Intervals < 10%

16

Composite Profile Development

• Defined in Load Profiling Guides Section 12.6.2.5

• Used for comparison if a single profile is to be used across several Weather Zones.

n

zz

n

zztz

t

E

fEf

1

1*

Where:

f*t = interval fraction at interval t for the composite Load Profile

Ez = total annual energy of ESI IDs in the proposed segment in Weather Zone z

fzt =interval fraction at interval t for the existing Load Profile using the weather data for Weather Zone

n = total number of Weather Zones

17

Profile and Sample ComparisonProfile and Sample ComparisonComparison for 12/26/04

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81 85 89 93

Interval

kW

h

Sample Profile Lower Confidence Limit Upper Confidence Limit

1

(Sunday)

1 Day of lowest total absolute kWh difference for 11/01/04 thru 10/31/05

18


0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81 85 89 93

Interval

kW

h


2

(Wednesday)

2 Day of 25th percentile total absolute kWh difference for 11/01/04 thru 10/31/05

19


0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81 85 89 93

Interval

kW

h


3

(Monday)

3 Day of median total absolute kWh difference for 11/01/04 thru 10/31/05

20


0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81 85 89 93

Interval

kW

h


4

(Wednesday)

4 Day of 75th percentile total absolute kWh difference for 11/01/04 thru 10/31/05

21


0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81 85 89 93

Interval

kW

h


5

(Wednesday)

5 Day of highest total absolute kWh difference for 11/01/04 thru 10/31/05

22

Profile and Sample ComparisonProfile and Sample Comparison

Monthly kWh

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

Nov '04 Dec '04 Jan '05 Feb '05 Mar '05 Apr '05 May '05 Jun '05 Jul '05 Aug '05 Sep '05 Oct '05

kW

h

Profile Sample

23

Profile and Sample DifferencesProfile and Sample DifferencesDistribution of Absolute kWh Differences

0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

0.00 -

0.01

0.02 -

0.03

0.04 -

0.05

0.06 -

0.07

0.08 -

0.09

0.10 -

0.11

0.12 -

0.13

0.14 -

0.15

0.16 -

0.17

0.18 -

0.19

0.20 -

0.21

0.22 -

0.23

0.24 -

0.25

0.26 -

0.27

0.28 -

0.29

0.30 -

0.31

0.32 -

0.33

0.34 -

0.35

0.36 -

0.37

0.38 -

0.39

0.40 -

0.41

0.42 -

0.43

0.44 -

0.45

kWh Range

Inte

rva

l Co

un

t

24

Profile and Sample DifferencesProfile and Sample DifferencesStatistically Significant Differences

0

20

40

60

80

100

120

1.81 - 1.90 1.91 - 2.00 2.01 - 2.10 2.11 - 2.20 2.21 - 2.30 2.31 - 2.40 2.41 - 2.50 2.51 - 2.60 2.61 - 2.70 2.71 - 2.80

Sample kWh Range

Pe

rce

nt

Unscaled Sample Scaled Sample

25

Profile and Sample DifferencesProfile and Sample DifferencesStatistically Significant Differences

0

20

40

60

80

100

120

SunM

on TueW

ed Thu FriSat Hol

Fall

Spring

Summ

er

Win

ter

All Int

erva

ls

Pe

rce

nt


26

Profile and Sample DifferencesProfile and Sample DifferencesMedian Differences -- Scaled Sample minus Profile

for 11/01/04 thru 10/31/05

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0kW

h

Median 5th Percentile 95th Percentile

Sun Mon Tue Wed Thu Fri Sat Hol

27

Differences for FallDifferences for FallMedian Differences -- Scaled Sample minus Profile

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0k

Wh



28

Differences for Winter 2004-2005Differences for Winter 2004-2005Median Differences -- Scaled Sample minus Profile

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0k

Wh



29

Differences for Spring 2005Differences for Spring 2005Median Differences -- Scaled Sample minus Profile

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0k

Wh



30

Differences for Summer 2005Differences for Summer 2005Median Differences -- Scaled Sample minus Profile

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0k

Wh



31

Profile and Unscaled Sample DifferencesProfile and Unscaled Sample Differences(Unscaled Sample minus Profile) vs. Profile

for 11/01/04 thru 10/31/05

-80

-60

-40

-20

0

20

40

60

80

1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6

Profile Interval kWh

Pe

rce

nt

Dif

fere

nc

e

Median 5th Percentile 95th Percentile Regression on Profile kWh

32

Profile and Sample DifferencesProfile and Sample DifferencesDistribution of kWh Percent Differences

[(sample - profile) / sample]

0

1,000

2,000

3,000

4,000

5,000

6,000

<= -25

- 25

to -2

0

- 20

to -1

5

- 15

to -1

0

- 10

to -5

- 5 to

00

to 5

5 to

10

10 to

15

15 to

20

> 20

Percent Difference

Inte

rva

l Co

un

t


33

Oil Gas LRS vs Composite ProfileLoad Factor

Month Oil_Gas_LRS Composite ProfileJ an 2005 91.2% 82.2%Feb 2005 89.2% 80.9%Mar 2005 90.2% 81.4%Apr 2005 90.1% 71.8%May 2005 91.0% 68.1%J un 2005 87.8% 76.5%J ul 2005 86.3% 78.3%Aug 2005 88.9% 77.7%Sep 2005 88.8% 76.4%Oct 2005 88.5% 69.6%Nov 2004 89.6% 81.1%Dec 2004 86.3% 79.1%

Year 86.1% 67.8%

Load Factor

34

Oil Gas LRS vs Composite ProfileOn Peak vs Off Peak kWh

Month Oil_Gas_LRSComposite

Profile Oil_Gas_LRSComposite

Profile Oil_Gas_LRSComposite

Profile

J an '05 2,418 2,668 4,608 4,372 52.5% 61.0%Feb '05 2,113 2,366 4,186 4,008 50.5% 59.0%Mar '05 2,695 2,999 4,272 4,033 63.1% 74.4%Apr '05 2,281 2,590 4,506 4,243 50.6% 61.1%May '05 2,445 2,706 4,636 4,258 52.7% 63.5%J un '05 2,584 2,836 4,231 3,903 61.1% 72.6%J ul '05 2,152 2,361 4,906 4,617 43.9% 51.1%Aug '05 2,787 3,015 4,418 4,034 63.1% 74.7%Sep '05 2,361 2,603 4,671 4,321 50.6% 60.2%Oct '05 2,436 2,807 4,665 4,416 52.2% 63.6%Nov '04 2,365 2,670 4,303 4,063 55.0% 65.7%Dec '04 2,517 2,765 4,403 4,185 57.2% 66.1%Year 29,154 32,385 53,803 50,452 54.2% 64.2%

On Peak Off PeakOn Peak kWh Off Peak kWh On_Pk / Off_Pk Ratio

35

Oil Gas LRS vs Composite ProfileMonthly kWh Fractions


ProfileCoast East FWest NCent North SCent South West

J an '05 8.5% 8.5% 7.8% 8.3% 8.2% 8.3% 8.7% 8.3% 7.5% 8.4%Feb '05 7.6% 7.7% 6.9% 7.1% 7.4% 7.1% 7.3% 7.2% 6.8% 7.5%Mar '05 8.4% 8.5% 7.4% 7.5% 7.5% 7.3% 7.5% 7.4% 7.4% 7.6%Apr '05 8.2% 8.2% 7.3% 7.1% 7.0% 7.0% 6.9% 7.0% 7.6% 7.2%May '05 8.5% 8.4% 8.1% 8.0% 8.1% 7.9% 7.8% 7.9% 8.3% 7.9%J un '05 8.2% 8.1% 9.5% 9.4% 9.5% 9.4% 9.2% 9.2% 9.5% 9.1%J ul '05 8.5% 8.4% 9.8% 9.7% 9.8% 9.8% 9.6% 9.7% 9.8% 9.7%Aug '05 8.7% 8.5% 10.1% 10.1% 9.4% 10.2% 10.0% 10.1% 10.2% 9.4%Sep '05 8.5% 8.4% 9.6% 9.7% 9.2% 9.6% 9.2% 9.6% 9.6% 9.2%Oct '05 8.6% 8.7% 8.1% 7.9% 7.6% 7.9% 7.8% 7.9% 8.3% 7.8%Nov '04 8.0% 8.1% 7.3% 7.2% 7.6% 7.1% 7.3% 7.2% 7.3% 7.6%Dec '04 8.3% 8.4% 7.9% 8.2% 8.7% 8.3% 8.7% 8.5% 7.6% 8.7%




kWh Monthly FractionBUSNODEM Profile

BUSLOLF Profile

36

Oil Gas LRS vs Composite ProfileMonthly kWh Fractions






J an '05 8.5% 8.5% 7.6% 7.3% 7.8% 7.2% 7.2% 7.2% 7.5% 7.8%

Feb '05 7.6% 7.7% 6.9% 6.6% 7.0% 6.5% 6.5% 6.5% 6.9% 7.1%Mar '05 8.4% 8.5% 7.8% 7.6% 8.1% 7.5% 7.5% 7.5% 7.9% 8.1%Apr '05 8.2% 8.2% 8.0% 7.8% 8.1% 7.9% 7.8% 7.8% 8.2% 8.2%May '05 8.5% 8.4% 8.7% 8.9% 8.7% 8.9% 8.9% 8.8% 8.8% 8.7%J un '05 8.2% 8.1% 9.2% 9.6% 9.1% 9.7% 9.8% 9.7% 9.1% 8.9%J ul '05 8.5% 8.4% 9.5% 10.0% 9.3% 10.1% 10.2% 10.1% 9.5% 9.3%Aug '05 8.7% 8.5% 9.6% 10.0% 9.2% 10.1% 10.2% 10.2% 9.5% 9.2%Sep '05 8.5% 8.4% 9.1% 9.6% 8.9% 9.6% 9.5% 9.7% 9.0% 8.8%Oct '05 8.6% 8.7% 8.4% 8.3% 8.4% 8.4% 8.2% 8.3% 8.5% 8.4%Nov '04 8.0% 8.1% 7.6% 7.3% 7.7% 7.1% 7.1% 7.2% 7.7% 7.7%Dec '04 8.3% 8.4% 7.6% 7.1% 7.7% 7.1% 7.2% 7.1% 7.5% 7.8%

BUSHILF Profile

kWh Monthly FractionBUSMEDLF Profile

37

Oil Gas LRS vs Composite Profile

Day of Week Net Diff Abs Diff Abs Percent Diff RMSESun 0.220228282 0.244 10.31 0.079Mon -0.067740962 0.263 11.15 0.095Tue -0.098227191 0.270 11.40 0.101Wed -0.093039739 0.271 11.46 0.103Thu -0.073884154 0.272 11.53 0.102Fri -0.051388848 0.251 10.59 0.086Sat 0.142200248 0.189 7.92 0.053

Holiday 0.095158417 0.207 8.96 0.063

Month Net Diff Abs Diff Abs Percent Diff RMSEJ an '05 -7.03186E-15 0.213 8.98 0.059Feb '05 3.12366E-15 0.223 9.41 0.064Mar '05 -6.93651E-15 0.237 10.04 0.071Apr '05 7.31373E-15 0.271 11.39 0.102May '05 -6.53763E-15 0.300 12.81 0.132J un '05 -2.33193E-15 0.266 11.40 0.098J ul '05 -7.9842E-15 0.258 10.98 0.095Aug '05 -4.19781E-15 0.251 10.57 0.085Sep '05 5.30563E-15 0.255 10.58 0.092Oct '05 -8.27885E-15 0.275 11.32 0.114Nov '04 -1.59286E-15 0.240 10.28 0.076Dec '04 4.23034E-15 0.214 9.17 0.062

Year -2.16517E-15 0.250 10.58 0.088

Mean Scaled kWh Differences

38

Oil Gas LRS vs Composite Profile

Day of Week Fraction Diff Abs Fraction diff Percent Fraction Diff RMSESun 0.003059061 0.0031 0.095 0.0000113Mon -0.000940054 0.0013 0.040 0.0000028Tue -0.001366071 0.0016 0.049 0.0000038Wed -0.001289419 0.0016 0.050 0.0000042Thu -0.001030348 0.0015 0.047 0.0000040Fri -0.000721606 0.0013 0.040 0.0000028Sat 0.001977438 0.0021 0.063 0.0000055

Holiday 0.00134823 0.0023 0.070 0.0000069

Month Fraction Diff Abs Fraction diff Percent Fraction Diff RMSEJ an 2005 -9.7816E-17 0.0015 0.046 0.0000032Feb 2005 4.73332E-17 0.0017 0.047 0.0000039Mar 2005 -9.23321E-17 0.0015 0.047 0.0000033Apr 2005 1.05009E-16 0.0020 0.061 0.0000063May 2005 -8.696E-17 0.0028 0.087 0.0000099J un 2005 -3.00685E-17 0.0017 0.050 0.0000039J ul 2005 -1.10798E-16 0.0018 0.056 0.0000050Aug 2005 -5.88687E-17 0.0013 0.039 0.0000025Sep 2005 6.97359E-17 0.0018 0.054 0.0000041Oct 2005 -1.06881E-16 0.0023 0.071 0.0000082Nov 2004 -1.8735E-17 0.0019 0.057 0.0000049Dec 2004 5.78614E-17 0.0015 0.048 0.0000045

Year -2.81263E-17 0.0018 0.055 0.0000050

Average Daily Fraction Differences

39

Load Weighted Average Price (LWAP) in $/Mwh

• An ideal profile model is applied to a homogeneous set of ESI IDs

• Oil/Gas ESI-ID’s are dissimilar in both shape and load factor

• If they have similar Load Weighted Average Prices (LWAP) they can be settled accurately with the same profile

• For an ESI ID, LWAP is computed as

• LWAP comparisons were performed to assess

similarities.

sNoInterval

i

i

sNoInterval

i

iii kWhMCPEkWhLWAP11

*

40

Load Weighted Average Price (LWAP) in $/Mwh

Congestion Zone

Weather Zone

Unweighted Avg MCPE

Profile Profile Profile Profile

EAST EAST 61.0 61.4 (1) 65.0 62.8 (1) 71.8

EAST NORTH 61.0 61.0 (1) 68.4 65.2 (3) 71.7

NORTH EAST 61.9 62.1 (3) 66.0 57.5 (2) 69.7 59.8 (2) 73.2

NORTH NCENT 61.9 74.9 (2) 70.1 61.5 (1) 73.7 67.1 (3) 68.2

WEST FWEST 61.7 61.4 (58) 63.4 63.9 (10) 67.8 63.6 (79) 74.6 58.9 (15) 67.6

WEST NCENT 61.7 61.2 (4) 65.8 65.0 (9) 69.6 58.7 (5) 72.9 61.4 (4) 67.7

WEST NORTH 61.7 61.6 (21) 65.7 59.2 (17) 69.1 62.9 (15) 72.5 59.2 (5) 67.2

WEST WEST 61.7 61.1 (15) 63.3 64.3 (18) 67.6 60.3 (22) 74.5 54.1 (4) 67.3

AVG 61.5 64.9 63.7 68.9 61.9 73.1 60.1 67.6

Notes:

AVG is the simple average of the columns and does not imply anything regarding the sample and population.

Values in ( ) are counts of sample points.

BUSHILF BUSMEDLF BUSLOLF BUSNODEM

Oil/Gas SPts

Oil/Gas SPts

Oil/Gas SPts

Oil/Gas SPts

41

Population LWAP MPU Estimation

Estimated LWAP Mean Per Unit (MPU):

K

NoStrata

K

KMPU LWAPWLWAP

1

Where:

k

n

i

i

Kn

LWAPLWAP

k

1

index stratumk

index point samplei

k stratum in size samplekn

weightstratumkW

42

Population LWAP MPU Confidence Limits Variance of LWAP Mean Per Unit (MPU):

k

NnMPU

n

sWLWAPV k

kk

NoStrata

K

K

2

1

2

1ˆ

Where:

k

k

i

k

n

i

K

n

LWAPLWAPs

1

22

index stratumk

index point samplei


weightstratumkW

90 Percent Confidence Intervals:

MPUMPU LWAPVLWAP ˆ*645.1

MPUMPU LWAPVLWAP ˆ*645.1

43

Population LWAP Estimation

Energy Weighted Estimated LWAP Weighted by Usage:

NoStrat

k

n

i

NoStrata

k

n

i

k

kik

k

kiikpopEWLWAPEWLWAP

Where:

index stratumk

index point samplei


weightstratumkW

Variance of LWAP Weighted by Usage:

NoStrata

k

n

i

k

popkikikLWAPLWAPEWV 2

VDeviationdardS _tan

Where:

index stratumk

index point samplei


weightstratumkW

LWAP Variance is the Measure of Homogeneity referenced in the LPG

44

Comparison of Estimated LWAP

Analysis Year

Analysis Month

Est. LWAP $/Mwh Variance90% Conf

Interval LowEst. LWAP

$/Mwh90% Conf

Interval HighLWAP of

Composite Profile

2004 11 47.30 2.17 47.85 47.97 48.08 48.65

2004 12 44.27 1.16 43.07 43.13 43.19 45.49

2005 1 44.03 1.79 43.42 43.48 43.53 44.20

2005 2 41.01 0.70 40.38 40.41 40.44 40.75

2005 3 47.81 0.54 48.30 48.33 48.37 48.64

2005 4 53.06 0.83 53.66 53.76 53.86 54.29

2005 5 48.91 2.52 49.74 49.83 49.92 52.51

2005 6 62.20 23.93 61.04 61.24 61.43 65.62

2005 7 72.33 2.71 72.56 72.65 72.73 75.89

2005 8 90.34 10.71 90.28 90.51 90.74 95.36

2005 9 95.70 6.25 93.98 94.08 94.17 102.21

2005 10 94.42 6.84 94.09 94.14 94.20 98.97

61.73 5.12 59.12 59.41 59.69 64.70

Note: The study period is 11/01/04 - 10/31/05

ESTIMATED LWAP WT'D BY USAGE ESTIMATED LWAP MEAN PER UNIT

Study Period

45

Weather Sensitivity Analysis Definition

• Defined in Protocols Section 11.4.3.1

• The following variables are calculated for each business day (excluding weekends and holidays):

– Daily kWh

– Average weather zone daily temp = ((Max + Min)/2)

• A correlation factor, R-Square (Pearson Product Moment Coefficient of Determination), is calculated for each oil/gas sample point

• If the resulting R-Square value is greater than or equal to 0.6, then the sample point is defined as “Weather Sensitive”.

46

Weather Sensitivity Analysis Definition

• Three weather sensitivity studies were performed.– Summer: 06/01/05 – 09/31/05– Winter: 12/01/04 – 02/28/05– Study Period: 11/01/04 – 10/31/05

47

Weather Sensitivity Analysis

Oil/Gas Weather Sensitivity AnalysisDistribution of RSquare Values

Summer - June 1 thru Sept 30 2005

0.0

10.0

20.0

30.0

40.0

50.0

60.0

0.0<=0.025 0.025<=0.05 0.05<=0.075 0.075<=0.10 0.1<=0.15 0.15<=0.20 0.2<=0.25 0.3<=0.35

RSquare Value Range

Pe

rce

nt

of

Sa

mp

le P

oin

ts i

n R

Sq

ua

re R

an

ge

48


Oil/Gas Weather Sensitivity AnalysisDistribution of RSquare Values

Winter - Dec 1 2004 thru Feb 28 2005

0.0

10.0

20.0

30.0

40.0

50.0

60.0

RSquare Value Range

Perc

en

t o

f S

am

ple

Po

ints

in

RS

qu

are

Ran

ge

49


Oil/Gas Sample Point 1with Weather Sensitivity RSq >= 0.6for Winter Period 12/01/04 - 02/28/05

0

5

10

15

20

25

30

35

40

45

20 30 40 50 60 70 80

Daily Average Temp

Da

ily

Su

m k

Wh

Winter StudyRSq = 0.613

50


Sample Point 1 with Winter RSq >= 0.6

for Study Period 11/01/04 - 10/31/05

0

5

10

15

20

25

30

35

40

45

20 30 40 50 60 70 80 90 100

Daily Average Temp

Da

ily

Su

m k

Wh

51


Oil/Gas Sample Point 2with Weather Sensitivity RSq >= 0.6for Winter Period 12/01/04 - 02/28/05

0

100

200

300

400

500

600

700

800

900

20 25 30 35 40 45 50 55 60 65 70

Daily Average Temp

Da

ily

Su

m k

Wh

Winter StudyRSq = 0.776

52


Sample Point 2 with Winter RSq >= 0.6

for Study Period 11/01/04 - 10/31/05

0

100

200

300

400

500

600

700

800

900

10 20 30 40 50 60 70 80 90 100

Daily Average Temp

Da

ily

Su

m k

Wh

53


Profile_Type WZone RSq Profile_Type WZone RSq

BUSHILF EAST 0.850 BUSMEDLF EAST 0.882

BUSHILF FWEST 0.814 BUSMEDLF FWEST 0.879

BUSHILF NCENT 0.897 BUSMEDLF NCENT 0.924

BUSHILF NORTH 0.918 BUSMEDLF NORTH 0.913

BUSHILF SCENT 0.853 BUSMEDLF SCENT 0.851

BUSHILF WEST 0.806 BUSMEDLF WEST 0.885

BUSLOLF EAST 0.767 BUSNODEM EAST 0.809

BUSLOLF FWEST 0.894 BUSNODEM FWEST 0.846

BUSLOLF NCENT 0.833 BUSNODEM NCENT 0.875

BUSLOLF NORTH 0.813 BUSNODEM NORTH 0.847

BUSLOLF SCENT 0.778 BUSNODEM SCENT 0.801

BUSLOLF WEST 0.913 BUSNODEM WEST 0.852

R-SQUARED ANALYSIS OF PROFILES FOR SUMMER PERIOD

54


Profile_Type WZone RSq Profile_Type WZone RSq

BUSHILF EAST 0.594 BUSMEDLF EAST 0.021

BUSHILF FWEST 0.626 BUSMEDLF FWEST 0.010

BUSHILF NCENT 0.395 BUSMEDLF NCENT 0.230

BUSHILF NORTH 0.020 BUSMEDLF NORTH 0.784

BUSHILF SCENT 0.686 BUSMEDLF SCENT 0.004

BUSHILF WEST 0.671 BUSMEDLF WEST 0.000

BUSLOLF EAST 0.000 BUSNODEM EAST 0.520

BUSLOLF FWEST 0.881 BUSNODEM FWEST 0.855

BUSLOLF NCENT 0.147 BUSNODEM NCENT 0.808

BUSLOLF NORTH 0.395 BUSNODEM NORTH 0.916

BUSLOLF SCENT 0.031 BUSNODEM SCENT 0.747BUSLOLF WEST 0.889 BUSNODEM WEST 0.881

R-SQUARED ANALYSIS OF PROFILES FOR WINTER PERIOD

Documents

Oil & Gas Final Sample Analysis April 27, 2006. 2 Background Information TXU ED provided a list of ESI IDs with SIC codes indicating Oil & Gas (8,583)