1 ercot lrs sample design review pwg presentation march 27, 2007

1

ERCOT

LRS Sample

Design Review

PWG Presentation

March 27, 2007

2

Overview

• Background information• Review of different options considered• Summary results of Option 1- 3• Class level MWh & Dollars by Profile Type/

WZone• Precision versus sample size• Review and discussion of Option chosen• Review of existing sample points• Reference to PUCT Rule 25.131 Section C

3

Background Information

• ERCOT presented LRS precision analysis and sample design ideas and options at the June 28, 2006 meeting.

• For Round 1 of the LRS sample design ERCOT offered to coordinate our sample designs with all of the TDSPs; only TXU-EDs’ was interested and we worked with them and incorporated their sample into ours. We are doing this again for Round 2.

• At the request of AEP ERCOT performed analysis to determine if it was necessary to have a separate primary voltage sample

• Analysis indicates 4 cells with 40 Sample Points each totaling 160 Primary Voltage Sample Points

4

Options for Determining Round Two Sample Size Increases

• Option 1: – Determine minimum sample size needed to obtain ±10% Accuracy at 90% Confidence for a selected

percent of intervals for the year independently for each Profile Type / Weather Zone Combination

• For Options 2 – 5 ERCOT recomputed daily energy totals and dollars– Used SAS data aggregation tool developed for transition analysis– Applied load profiles from new models to spread monthly LSEG totals from Lodestar to intervals– Multiplied by weather zone weighted MCPE to associate a dollar value with each interval

• Option 2:– Determine minimum sample size needed to obtain ±10% Accuracy at 90% Confidence for enough intervals

to account for a selected percent of the MWh for each Profile Type / Weather Zone Combination

• Option 3:– Determine minimum sample size needed to obtain ±10% Accuracy at 90% Confidence for enough intervals

to account for a selected percent of the dollars (ΣMWh * MCPE) for each Profile Type / Weather Zone Combination

• Option 4:– Iteratively allocate increments of 20 sample points to the Profile Type / Weather Zone Combination which

produces the most gain in terms of reducing MWh estimation error

• Option 5:– Iteratively allocate increments of 20 sample points to the Profile Type / Weather Zone Combination which

produces the most gain in terms of reducing Dollar estimation error

5

% of Intervals 0 1 5 10 25 50 75 90 95 99 100BUSHILF 14 36 48 60 85 132 206 303 385 560 2,977BUSMEDLF 365 606 807 970 1,379 2,025 3,013 4,386 5,765 19,994 49,675BUSLOLF 109 211 285 348 511 768 1,083 1,410 1,634 2,088 18,203BUSNODEM 542 948 1,186 1,364 1,754 2,586 3,817 5,537 7,662 13,525 33,123RESHIWR 197 395 562 701 1,076 1,761 2,662 3,673 4,476 6,759 24,736RESLOWR 146 309 435 540 781 1,175 1,764 2,536 3,167 4,923 15,963

Total 1,373 2,505 3,323 3,983 5,586 8,447 12,545 17,845 23,089 47,849 144,677

To

tal

Option 1• To obtain ±10% Accuracy at 90% Confidence By

Profile Type - Independent of Interval

For example: to obtain ±10% Accuracy at 90% Confidence for 50% of the intervals for all Profile Type/Weather Zone combinations would require a sample size of 8,447 points

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Option 2• To obtain ±10% Accuracy at 90% Confidence for Intervals Accounting

for Selected Percents of the MWH within Each Profile Type

For example: to obtain ±10% Accuracy at 90% Confidence for intervals accounting for 50% of the MWh for each of the Profile Type / Weather Zone combinations would require a sample size of 7,438 points

% of MWH 0 1 5 10 25 50 60 70 75 80 85 90 95 99 100BUSHILF 14 30 48 56 82 128 152 181 198 220 249 290 372 509 2,977BUSMEDLF 365 524 689 813 1,114 1,677 1,970 2,329 2,575 2,871 3,256 3,814 4,873 11,546 49,675BUSLOLF 109 176 252 306 443 684 788 906 980 1,062 1,172 1,304 1,507 1,876 18,203BUSNODEM 542 868 1,151 1,327 1,714 2,448 2,856 3,338 3,639 4,025 4,508 5,213 6,966 11,935 33,123RESHIWR 197 326 483 594 890 1,487 1,805 2,160 2,366 2,621 2,914 3,316 3,998 5,596 24,736RESLOWR 146 246 362 433 611 964 1,134 1,358 1,501 1,665 1,882 2,187 2,718 3,987 15,963

Total 1,373 2,171 2,990 3,539 4,879 7,438 8,765 10,342 11,334 12,544 14,066 16,214 20,529 35,548 144,777

To

tal

7

• To obtain ±10% Accuracy at 90% Confidence for Intervals Accounting for Selected Percents of the dollars within each Profile Type

Continues on next slide

For example: to obtain ±10% Accuracy at 90% Confidence for intervals accounting for 50% of the Dollars for each of the Profile Type / Weather Zone combinations would require a sample size of 6,969 points

% of Dollars 0 1 5 10 25 50 60 70BUSHILF 14 29 47 53 80 122 142 170BUSMEDLF 365 482 644 741 985 1,503 1,784 2,123BUSLOLF 109 167 231 271 381 606 709 815BUSNODEM 542 860 1,168 1,355 1,782 2,600 2,992 3,436RESHIWR 197 310 437 525 750 1,237 1,533 1,865RESLOWR 146 237 339 402 554 851 1,018 1,237

Total 1,373 2,086 2,871 3,357 4,557 6,969 8,238 9,716

To

tal

Option 3

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• To obtain ±10% Accuracy at 90% Confidence for Intervals Accounting for Selected Percents of the dollars within each Profile Type

% of Dollars 75 80 85 90 95 99 100BUSHILF 189 209 236 278 352 492 2,977BUSMEDLF 2,335 2,605 2,930 3,446 4,367 7,888 49,675BUSLOLF 882 966 1,062 1,197 1,399 1,796 18,203BUSNODEM 3,725 4,095 4,574 5,290 7,135 12,117 33,123RESHIWR 2,075 2,309 2,614 2,983 3,641 5,077 24,736RESLOWR 1,367 1,534 1,737 2,034 2,537 3,781 15,963

Total 10,648 11,798 13,238 15,318 19,526 31,250 144,777

To

tal

Option 3

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Class Level MWH & Dollars

Is accuracy more important for RESLOWR (33.4% of Dollars) than for BUSNODEM (1.6% of Dollars)?

19 Month 19Month MWh % - Profile Total % 19Month MWhProfile / Wzone MWh * MCPE (Dollars) 19Month MWh * MCPE LWAPBUSHILF 21,989,953 1,388,130,633 10.7% 9.8% 63.13BUSMEDLF 25,407,213 1,751,971,485 12.4% 12.4% 68.96BUSLOLF 34,802,034 2,302,682,583 16.9% 16.3% 66.17BUSNODEM 3,629,145 229,275,584 1.8% 1.6% 63.18RESHIWR 54,084,985 3,712,021,098 26.3% 26.3% 68.63RESLOWR 65,807,466 4,714,305,518 32.0% 33.4% 71.64

Total 205,720,796 14,098,386,902 100.0% 100.0% 68.53

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Class Level MWH & Dollars - Descending Order by Dollars

* Note: Dollars = Σ (MWh * MCPE)Continues on next slide

Top 5 classes account for 53% of the MWh and 54% of the dollars

19-Month Cumlt. Cumlt.% Cumlt. Cumlt.%rank Profile / Wzone MWh Dollars* MWh Ttl MWh Dollars Ttl Dollars

1 RESLOWR_COAST 28,755,663 2,058,500,827 28,755,663 14% 2,058,500,827 15%2 RESLOWR_NCENT 25,932,725 1,889,284,910 54,688,388 27% 3,947,785,737 28%3 RESHIWR_NCENT 25,170,472 1,752,749,197 79,858,859 39% 5,700,534,934 40%4 BUSMEDLF_NCENT 15,449,309 1,030,463,871 95,308,169 46% 6,730,998,806 48%5 RESHIWR_COAST 13,228,059 906,412,483 108,536,228 53% 7,637,411,289 54%6 BUSMEDLF_COAST 11,405,935 753,826,626 119,942,163 58% 8,391,237,915 60%7 BUSLOLF_NCENT 9,882,020 697,329,751 129,824,183 63% 9,088,567,666 64%8 BUSHILF_NCENT 9,289,014 595,340,798 139,113,197 68% 9,683,908,464 69%

9 BUSLOLF_COAST 8,612,974 586,474,328 147,726,171 72% 10,270,382,792 73%10 RESHIWR_SOUTH 7,924,123 524,229,612 155,650,294 76% 10,794,612,404 77%11 BUSHILF_COAST 7,012,401 440,544,629 162,662,695 79% 11,235,157,033 80%12 RESLOWR_SOUTH 3,707,166 245,428,322 166,369,861 81% 11,480,585,355 81%13 BUSMEDLF_SOUTH 3,207,940 205,503,900 169,577,801 83% 11,686,089,255 83%14 BUSLOLF_SOUTH 2,816,609 185,696,415 172,394,409 84% 11,871,785,670 84%15 RESHIWR_EAST 2,574,739 176,656,091 174,969,148 85% 12,048,441,762 85%16 BUSHILF_SOUTH 2,375,129 144,688,043 177,344,277 86% 12,193,129,805 86%

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* Dollars = Annual MWh * MCPEContinues on next slide


17 RESLOWR_EAST 1,795,949 125,803,195 179,140,226 87% 12,318,933,000 87%18 RESLOWR_NORTH 1,580,573 111,940,734 180,720,799 88% 12,430,873,735 88%19 RESHIWR_NORTH 1,499,513 102,836,931 182,220,312 89% 12,533,710,666 89%20 RESLOWR_FWEST 1,444,265 102,313,952 183,664,577 89% 12,636,024,618 90%21 RESHIWR_WEST 1,436,721 96,312,637 185,101,299 90% 12,732,337,255 90%22 BUSNODEM_NCENT 1,537,514 95,849,300 186,638,813 91% 12,828,186,556 91%23 RESLOWR_SCENT 1,305,328 92,277,972 187,944,141 91% 12,920,464,528 92%24 RESHIWR_FWEST 1,340,030 90,813,567 189,284,171 92% 13,011,278,095 92%25 RESLOWR_WEST 1,285,798 88,755,604 190,569,969 93% 13,100,033,699 93%26 BUSNODEM_COAST 1,304,968 82,914,041 191,874,937 93% 13,182,947,740 94%27 BUSMEDLF_EAST 1,209,610 80,858,842 193,084,547 94% 13,263,806,582 94%28 BUSLOLF_EAST 1,126,287 78,322,602 194,210,834 95% 13,342,129,184 95%29 BUSHILF_FWEST 1,212,446 75,408,364 195,423,279 95% 13,417,537,548 95%30 BUSMEDLF_FWEST 1,103,530 72,034,036 196,526,810 96% 13,489,571,585 96%31 BUSLOLF_FWEST 992,852 68,460,782 197,519,662 96% 13,558,032,367 96%32 BUSMEDLF_NORTH 940,794 62,626,744 198,460,455 97% 13,620,659,111 97%

Bottom 28 classes account for only 10% of the MWh and dollars

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* Dollars = Annual MWh * MCPE

Continues on next slide


33 RESHIWR_SCENT 911,327 62,010,580 199,371,783 97% 13,682,669,691 97%34 BUSMEDLF_WEST 940,393 61,519,838 200,312,175 97% 13,744,189,529 97%35 BUSLOLF_NORTH 813,779 56,508,105 201,125,954 98% 13,800,697,634 98%36 BUSLOLF_WEST 767,768 52,046,991 201,893,722 98% 13,852,744,626 98%37 BUSHILF_EAST 664,628 42,102,131 202,558,350 99% 13,894,846,757 99%38 BUSHILF_NORTH 392,006 39,307,134 202,950,357 99% 13,934,153,891 99%39 BUSMEDLF_SCENT 544,524 35,848,725 203,494,880 99% 13,970,002,616 99%40 BUSHILF_WEST 499,266 30,928,517 203,994,146 99% 14,000,931,133 99%41 BUSLOLF_SCENT 394,925 27,132,509 204,389,071 99% 14,028,063,642 100%42 BUSHILF_SCENT 317,290 19,811,017 204,706,361 100% 14,047,874,659 100%43 BUSNODEM_EAST 207,477 13,509,530 204,913,838 100% 14,061,384,189 100%44 BUSNODEM_FWEST 167,689 10,811,421 205,081,528 100% 14,072,195,609 100%45 BUSNODEM_NORTH 143,908 9,433,035 205,225,435 100% 14,081,628,644 100%46 BUSNODEM_SOUTH 111,224 6,950,418 205,336,659 100% 14,088,579,063 100%47 BUSNODEM_WEST 81,379 5,093,591 205,418,038 100% 14,093,672,654 100%48 BUSNODEM_SCENT 74,986 4,714,248 205,493,024 100% 14,098,386,902 100%

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Precision vs Sample Size

Precision at 90% Confidenceas a Function of Error Ratio and Sample Size

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0 50 100 150 200 250 300 350 400

Sample Size

Pre

cisi

on er=0.10

er=0.50

er=1.00

er=1.50

ratioerror er

1.645Z,Confidence%90For

sizesample

erZPrecision

•Increasing sample size has a diminishing return on precision improvement

•Error Ratio (thus Precision improvement) varies across Profile Types / Weather Zones and across intervals

•Thus the impact of adding sample points varies by Profile Type and Weather Zone

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Options 4 & 5• Options 4 & 5 iteratively allocate increments of 20 sample points to the next Profile Type /

Weather Zone Combination in order to produce the most gain in

– Reducing MWh (Option 4) estimation error (Precision × MWh) summed across all intervals– Reducing Dollar (Option 5) estimation error (Precision × Dollars) summed across all intervals

• The allocations are based on

– The MWh (or Dollars) associated with each of the Profile Type / Weather Zone combinations in each interval– The Error ratio in each interval for each Profile Type / Weather Zone combination– The cumulative number of sample points allocated by preceding iterations (including the original sample

size)– The precision improvement that would be realized by adding 20 sample points, and the diminishing return

on that improvement

• Minimum Sample Size

– Profile to profile migration resulted in numerous instances of small sample sizes within strata– Small sample sizes resulted in both accuracy degradation and the need to drop strata from load research

analysis – A minimum of 3 strata will be specified for each Profile Type / Weather Zone combination– A minimum of 40 sample points will be allocated to each stratum– Minimum sample size per Profile Type / Weather Zone combination will be 120

• Maximum Sample Size

– Maximum for Business Profile / Weather Zone combinations set to 400 – Maximum for Residential Profile / Weather Zone combinations set to 600

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Option 4 – MWh Error Reduction Optimization

(Option 4) Reducing MWh estimation error (Precision × MWh) summed across all intervals

Cumulative sample sizes are shown in increments of 1,000; they were determined iteratively in increments of 20 sample points

Sample Size 8000 9000 10000 11000 12000

BUSHILF_COAST 120 120 140 220 280BUSHILF_EAST 120 120 120 120 120BUSHILF_FWEST 120 120 120 120 120BUSHILF_NCENT 120 120 240 320 400BUSHILF_NORTH 120 120 120 120 120BUSHILF_SCENT 120 120 120 120 120BUSHILF_SOUTH 120 120 120 120 120BUSHILF_WEST 120 120 120 120 120BUSMEDLF_COAST 260 400 400 400 400BUSMEDLF_EAST 120 120 120 120 140BUSMEDLF_FWEST 120 120 140 200 260BUSMEDLF_NCENT 300 400 400 400 400BUSMEDLF_NORTH 120 120 120 120 120BUSMEDLF_SCENT 120 120 120 120 120BUSMEDLF_SOUTH 120 180 320 400 400BUSMEDLF_WEST 120 120 120 120 120BUSLOLF_COAST 200 300 400 400 400BUSLOLF_EAST 120 120 120 120 120BUSLOLF_FWEST 120 120 120 120 160BUSLOLF_NCENT 280 400 400 400 400BUSLOLF_NORTH 120 120 120 120 120BUSLOLF_SCENT 120 120 120 120 120BUSLOLF_SOUTH 120 120 160 240 300BUSLOLF_WEST 120 120 120 120 120BUSNODEM_COAST 120 120 160 240 300BUSNODEM_EAST 120 120 120 120 120BUSNODEM_FWEST 120 120 120 120 120BUSNODEM_NCENT 120 120 160 220 300BUSNODEM_NORTH 120 120 120 120 120BUSNODEM_SCENT 120 120 120 120 120BUSNODEM_SOUTH 120 120 120 120 120BUSNODEM_WEST 120 120 120 120 120

Sample Size 8000 9000 10000 11000 12000

RESHIWR_COAST 380 560 600 600 600RESHIWR_EAST 120 120 220 300 360RESHIWR_FWEST 120 120 120 160 220RESHIWR_NCENT 600 600 600 600 600RESHIWR_NORTH 120 120 120 180 240RESHIWR_SCENT 120 120 120 120 140RESHIWR_SOUTH 240 360 580 600 600RESHIWR_WEST 120 120 120 160 220RESLOWR_COAST 540 600 600 600 600RESLOWR_EAST 120 120 120 180 220RESLOWR_FWEST 120 120 120 160 200RESLOWR_NCENT 520 600 600 600 600RESLOWR_NORTH 120 120 120 160 200RESLOWR_SCENT 120 120 120 120 160RESLOWR_SOUTH 120 160 280 380 460RESLOWR_WEST 120 120 120 120 160

Percent Reduction MWH Error 76.5% 77.5% 78.1% 78.4% 78.7%

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Option 5 – Dollar Error Reduction Optimization

RESHIWR_COAST 380 560 600 600 600RESHIWR_EAST 120 120 220 300 360RESHIWR_FWEST 120 120 120 180 220RESHIWR_NCENT 600 600 600 600 600RESHIWR_NORTH 120 120 120 180 220RESHIWR_SCENT 120 120 120 120 140RESHIWR_SOUTH 220 360 560 600 600RESHIWR_WEST 120 120 120 160 220RESLOWR_COAST 560 600 600 600 600RESLOWR_EAST 120 120 120 180 240RESLOWR_FWEST 120 120 120 160 220RESLOWR_NCENT 520 600 600 600 600RESLOWR_NORTH 120 120 120 160 220RESLOWR_SCENT 120 120 120 120 160RESLOWR_SOUTH 120 160 280 380 480RESLOWR_WEST 120 120 120 120 160

Percent Reduction Dollar Error 76.5% 77.5% 78.1% 78.5% 78.7%

Sample Size 8000 9000 10000 11000 12000

BUSHILF_COAST 120 120 140 200 260BUSHILF_EAST 120 120 120 120 120BUSHILF_FWEST 120 120 120 120 120BUSHILF_NCENT 120 120 240 320 400BUSHILF_NORTH 120 120 120 120 120BUSHILF_SCENT 120 120 120 120 120BUSHILF_SOUTH 120 120 120 120 120BUSHILF_WEST 120 120 120 120 120BUSMEDLF_COAST 260 400 400 400 400BUSMEDLF_EAST 120 120 120 120 140BUSMEDLF_FWEST 120 120 140 200 240BUSMEDLF_NCENT 300 400 400 400 400BUSMEDLF_NORTH 120 120 120 120 120BUSMEDLF_SCENT 120 120 120 120 120BUSMEDLF_SOUTH 120 180 300 400 400BUSMEDLF_WEST 120 120 120 120 120BUSLOLF_COAST 200 300 400 400 400BUSLOLF_EAST 120 120 120 120 120BUSLOLF_FWEST 120 120 120 120 160BUSLOLF_NCENT 280 400 400 400 400BUSLOLF_NORTH 120 120 120 120 120BUSLOLF_SCENT 120 120 120 120 120BUSLOLF_SOUTH 120 120 160 220 280BUSLOLF_WEST 120 120 120 120 120BUSNODEM_COAST 120 120 180 240 300BUSNODEM_EAST 120 120 120 120 120BUSNODEM_FWEST 120 120 120 120 120BUSNODEM_NCENT 120 120 180 240 300BUSNODEM_NORTH 120 120 120 120 120BUSNODEM_SCENT 120 120 120 120 120BUSNODEM_SOUTH 120 120 120 120 120BUSNODEM_WEST 120 120 120 120 120

Sample Size 8000 9000 10000 11000 12000

(Option 5) Reducing Dollar estimation error (Precision × Dollars) summed across all intervals

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Dollar Error Reduction Based on Sample Size Increases

Sample Size

Incremental Dollar Error Reduction (19 Month)

Error Reduction per Incremental Sample Point (Annualized)

Incremental MWh Error Reduction (19 Month)

Error Reduction per Incremental Sample Point (Annualized)

4560 -- -- -- --5760 170,368,683 89,668 2,630,122 1,384 6000 59,872,350 157,559 916,007 3,817 6500 74,081,985 93,577 1,129,530 2,259 7000 51,048,186 64,482 782,336 1,565 7500 39,920,390 50,426 615,328 1,231 8000 32,550,371 41,116 500,334 1,001 8500 26,378,457 33,320 406,100 812 9000 20,806,066 26,281 325,652 651 9500 15,530,764 19,618 245,482 491

10000 11,461,324 14,477 181,097 362 10500 9,341,106 11,799 146,094 292 11000 7,917,458 10,001 123,359 247 11500 6,822,516 8,618 106,161 212 12000 6,002,526 7,582 93,068 186 12500 5,338,340 6,743 82,843 166 13000 4,817,731 6,086 75,127 150 13500 4,399,533 5,557 68,435 137 14000 4,015,099 5,072 62,632 125 14500 3,626,681 4,581 56,494 113 15000 3,282,507 4,146 50,961 102

Non - Optimized

Allocation of points

Optimized Allocation of Additional Points

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Primary Voltage Sample Review

• Four Business sample cells have significant saturation of primary voltage ESIIDs/energy

• These cells will have primary voltage strata included in their sample design (40 per stratum)

• Existing primary voltage sample points were selected based on separate stratified sample designs, complete retention not feasible because of sample point weighting issues

Profile Type WZoneEnergy Percent

ESIID Count

BUSHILF FWEST 47.1 782BUSHILF NORTH 4.8 115BUSLOLF FWEST 5.2 936BUSMEDLF FWEST 16.0 865

Note:Oil/Gas ESIID's supplied by AEP and TXU are removed from analysis

CELLS WITH AT LEAST 4 PERCENTPRIMARY VOLTAGE ENERGY

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Retainable Round 1 Sample Points

• Table shows retainable secondary sample points only• Non retained sample points may be selected for the round 2 sample• TDSPs should consider waiting until round 2 sample list is provided

to start recorder removal

COAST EAST FWEST NCENT NORTH SCENT SOUTH WESTRESHI 40 42 43 93 41 40 41 44RESLO 45 38 50 70 56 44 31 45BUSHI 17 16 12 21 22 16 15 18BUSMED 35 51 44 54 40 88 34 37BUSLO 75 84 76 77 76 78 80 68BUSNODEM 98 82 87 179 91 70 23 38

310 313 312 494 326 336 224 250

ALL TDSPS -- PROFILE_TYPE 2004 - 2007

RESHI 384 RESLO 379 BUSHI 137 BUSMED 383 BUSLO 614 BUSNODEM 668 Points same as 2004 2,565 Ttl Points no O & G 3,452 % POINTS - Eligible 74.3%

PROFILE_TYPE 2004 & 2007

CNP TXU-ED TNMP AEPC AEPNRESHI 35 249 7 58 35RESLO 43 239 9 41 47BUSHI 17 74 5 21 20BUSMED 33 249 8 49 44BUSLO 68 348 26 113 59BUSNODEM 92 492 21 29 34

288 1651 76 311 239

PROFILE_TYPE 2004 - 2007

20

PUC Rule §25.131, Load Profiling and Load Research

Section (C):Load research responsibility. Each TDU shall perform load research to support

ERCOT’s load profiling activities, as directed by ERCOT.1) ERCOT shall be responsible for load research sample design and sample point

selection for ERCOT-directed load profiling and load research samples. ERCOT shall coordinate with each TDU to optimize load research programs of both ERCOT and the TDU. The same samples shall be used to support both the TDU’s load research activities and ERCOT’s load profile research needs whenever reasonably possible. Each TDU shall coordinate with ERCOT to synchronize its load research cycles and sample replacement with those of ERCOT.

2) ERCOT, in consultation with the TDUs, shall specify the manner of data collection for ERCOT load profile research samples and the means and frequency of transmission of such information to ERCOT. Each TDU shall adhere to the specifications for data collection and transmission specified by ERCOT.

3) A TDU may recover its reasonably and necessary costs incurred in performing load profile research as required by this section.

4) This section shall not be interpreted to require a TDU to redeploy any existing samples that were deployed less than five years before the effective date of this section, although this section shall also not be interpreted as addressing the appropriateness of continued deployment of existing TDU samples apart from the ERCOT request to do so. Notwithstanding the foregoing, the TDU shall deploy additional samples as requested by ERCOT in order to support ERCOT’s load profiling activities.

1 ercot lrs sample design review pwg presentation march 27, 2007

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