1 ercot lrs precision analysis pwg presentation june 28, 2006

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ERCOT

LRS Precision Analysis

PWG Presentation

June 28, 2006

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Options for Determining Round Two Sample Size Increases

• Option 1: – Determine minimum sample size increase 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

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

selected percent of intervals such that all Profile Type / Weather Zone Combinations meet the accuracy target in all selected interval

• Option 3:– Determine minimum sample size increase 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 4:– Determine minimum sample size increase 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 5:– Iteratively allocate increments of 10 sample points to the Profile Type / Weather Zone Combination which

produces the most gain in terms of reducing MWh estimation error

• Option 6:– Iteratively allocate increments of 10 sample points to the Profile Type / Weather Zone Combination which

produces the most gain in terms of reducing Dollar estimation error

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

and Weather Zone - Independent of Interval

Minimum Sample Size Increase Required

Percent of Intervals 0 1 5 10 25 50 75 90 95 99 100BUSHILF_COAST 0 0 0 0 0 0 2 31 61 105 1,211BUSHILF_EAST 0 0 0 0 0 10 46 70 87 109 177BUSHILF_FWEST 0 0 0 0 0 0 0 0 0 51 180BUSHILF_NCENT 0 0 0 0 0 0 0 12 20 49 75BUSHILF_NORTH 0 0 0 0 0 0 0 2 9 22 92BUSHILF_SCENT 0 0 0 0 0 0 0 0 0 0 73BUSHILF_SOUTH 0 0 0 0 0 0 18 58 80 108 162BUSHILF_WEST 0 0 0 0 0 0 0 0 0 0 47

Increase Total 0 0 0 0 0 10 66 173 257 444 2,017

Percent of Intervals 0 1 5 10 25 50 75 90 95 99 100BUSMEDLF_COAST 0 0 0 0 0 0 26 54 74 140 1,433BUSMEDLF_EAST 0 0 0 0 0 5 35 67 87 139 392BUSMEDLF_FWEST 0 0 0 0 0 12 68 120 159 246 7,359BUSMEDLF_NCENT 0 0 0 0 0 0 0 8 23 47 214BUSMEDLF_NORTH 0 0 0 0 0 13 106 255 305 366 541BUSMEDLF_SCENT 0 0 0 0 0 0 0 0 0 0 9BUSMEDLF_SOUTH 0 0 0 0 49 167 342 597 819 1,484 3,537BUSMEDLF_WEST 0 0 0 0 0 0 0 0 3 43 399

Increase Total 0 0 0 0 49 197 577 1,101 1,470 2,465 13,884

For example: to obtain ±10% Accuracy at 90% Confidence for 50% of the intervals for BUSHILF_COAST would require a sample size increase of 10 points

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Minimum Sample Size Increase Required

Percent of Intervals 0 1 5 10 25 50 75 90 95 99 100BUSLOLF_COAST 0 0 0 3 39 108 203 328 436 886 2,550BUSLOLF_EAST 0 0 0 0 0 35 99 165 216 331 1,054BUSLOLF_FWEST 0 0 22 76 215 440 738 1,141 1,647 13,899 28,262BUSLOLF_NCENT 0 0 0 0 39 117 216 347 451 750 6,838BUSLOLF_NORTH 0 0 0 0 11 73 153 272 390 637 1,133BUSLOLF_SCENT 0 0 0 0 21 80 150 230 294 469 882BUSLOLF_SOUTH 0 0 0 0 30 96 189 326 446 818 2,075BUSLOLF_WEST 0 0 1 23 59 135 248 413 558 1,028 2,135

Increase Total 0 0 23 102 414 1,084 1,996 3,222 4,438 18,818 44,929

Percent of Intervals 0 1 5 10 25 50 75 90 95 99 100BUSNODEM_COAST 0 15 49 82 175 348 522 752 1,202 2,710 5,360BUSNODEM_EAST 0 17 48 64 106 185 342 570 767 1,159 3,291BUSNODEM_FWEST 0 8 39 65 130 271 408 534 619 972 3,234BUSNODEM_NCENT 0 0 0 0 0 102 317 511 677 1,060 2,615BUSNODEM_NORTH 24 88 116 131 177 258 371 557 726 1,181 3,221BUSNODEM_SCENT 21 87 117 136 176 260 420 690 1,224 2,663 6,032BUSNODEM_SOUTH 0 60 101 124 180 285 426 677 912 1,805 3,781BUSNODEM_WEST 2 30 57 80 144 261 406 588 772 1,406 3,258

Increase Total 47 305 527 682 1,088 1,970 3,212 4,879 6,899 12,956 30,792

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Increase of Sample Size

Percent of Intervals 0 1 5 10 25 50 75 90 95 99 100RESHIWR_COAST 0 3 24 38 81 150 241 362 460 742 3,624RESHIWR_EAST 0 0 22 42 95 194 325 485 639 1,205 3,232RESHIWR_FWEST 0 12 37 53 105 192 310 438 545 829 2,228RESHIWR_NCENT 0 0 0 0 27 145 274 391 467 654 1,937RESHIWR_NORTH 0 0 20 37 81 165 277 399 493 747 2,867RESHIWR_SCENT 0 1 20 34 84 180 307 463 589 872 2,200RESHIWR_SOUTH 0 0 13 26 63 145 274 416 520 759 2,610RESHIWR_WEST 0 0 13 33 77 153 247 351 427 641 2,224

Increase Total 0 16 149 263 613 1,324 2,255 3,305 4,140 6,449 20,922

Percent of Intervals 0 1 5 10 25 50 75 90 95 99 100RESLOWR_COAST 0 0 0 0 19 76 156 259 354 633 1,846RESLOWR_EAST 0 0 0 4 37 114 202 301 373 562 1,738RESLOWR_FWEST 0 5 21 37 68 120 208 332 428 697 2,543RESLOWR_NCENT 0 0 0 0 8 57 117 187 238 374 1,133RESLOWR_NORTH 0 0 3 14 45 97 170 250 311 463 1,034RESLOWR_SCENT 0 0 0 5 45 94 157 242 308 514 1,247RESLOWR_SOUTH 0 0 0 6 40 110 231 397 541 951 2,584RESLOWR_WEST 0 0 0 17 51 105 175 262 330 509 1,728

Increase Total 0 5 24 83 313 773 1,416 2,230 2,883 4,703 13,853

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

Profile Type - Independent of Interval

Percent of Intervals 0 1 5 10 25 50 75 90 95 99 100BUSHILF 0 0 0 0 0 10 66 173 257 444 2,017BUSMEDLF 0 0 0 0 49 197 577 1,101 1,470 2,465 13,884BUSLOLF 0 0 23 102 414 1,084 1,996 3,222 4,438 18,818 44,929BUSNODEM 47 305 527 682 1,088 1,970 3,212 4,879 6,899 12,956 30,792RESHIWR 0 16 149 263 613 1,324 2,255 3,305 4,140 6,449 20,922RESLOWR 0 5 24 83 313 773 1,416 2,230 2,883 4,703 13,853

Total 47 326 723 1,130 2,477 5,358 9,522 14,910 20,087 45,835 126,397

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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 increase of 5,358 points

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Option 2• To obtain ±10% Accuracy at 90% Confidence for all Profile

Types and Weather Zones - Within Each IntervalPercent of Intervals 0 1 10 25 50 75 90 95 99 100

BUSHILF_COAST 0 93 109 151 151 151 282 282 1,211 1,211BUSHILF_EAST 0 70 117 129 150 150 150 177 177 177BUSHILF_FWEST 0 13 99 103 103 180 180 180 180 180BUSHILF_NCENT 0 58 65 68 75 75 75 75 75 75BUSHILF_NORTH 0 16 30 33 92 92 92 92 92 92BUSHILF_SCENT 0 0 1 1 5 16 16 73 73 73BUSHILF_SOUTH 0 69 104 129 162 162 162 162 162 162BUSHILF_WEST 0 0 12 12 12 12 47 47 47 47

BUSHILF Sub-Total 0 319 537 626 750 838 1,004 1,088 2,017 2,017

Percent of Intervals 0 1 10 25 50 75 90 95 99 100BUSMEDLF_COAST 0 51 74 191 207 265 265 290 1,433 1,433BUSMEDLF_EAST 0 87 91 149 205 305 378 392 392 392BUSMEDLF_FWEST 0 109 266 287 329 329 461 461 461 7,359BUSMEDLF_NCENT 0 4 55 68 82 185 214 214 214 214BUSMEDLF_NORTH 0 97 305 416 461 484 500 500 541 541BUSMEDLF_SCENT 0 0 0 0 0 6 9 9 9 9BUSMEDLF_SOUTH 7 391 489 521 889 1,282 2,220 2,220 3,537 3,537BUSMEDLF_WEST 0 9 20 76 94 175 175 399 399 399

BUSMEDLF Sub-Total 7 748 1,300 1,708 2,267 3,031 4,222 4,485 6,986 13,884

For example: to obtain ±10% Accuracy at 90% Confidence for 50% of the intervals such that all Profile Type/Weather Zone combinations within those intervals would achieve that level of accuracy would require a sample size increase of 750 points for BUSHILF and 2,267 points for BUSMEDLF

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Types and Weather Zones - Within Each IntervalPercent of Intervals 0 1 10 25 50 75 90 95 99 100

BUSLOLF_COAST 20 203 363 557 805 1,268 1,431 1,714 2,550 2,550BUSLOLF_EAST 43 119 165 324 425 487 487 723 1,054 1,054BUSLOLF_FWEST 228 604 604 604 808 1,364 2,602 2,761 16,169 28,262BUSLOLF_NCENT 64 272 368 541 740 1,020 1,110 1,326 1,783 6,838BUSLOLF_NORTH 102 204 333 428 711 829 976 998 1,133 1,133BUSLOLF_SCENT 17 218 294 493 676 761 781 791 882 882BUSLOLF_SOUTH 81 189 347 537 671 1,066 1,066 1,893 2,075 2,075BUSLOLF_WEST 19 224 376 609 867 1,260 1,650 1,650 2,135 2,135

BUSLOLF Sub-Total 574 2,033 2,850 4,093 5,703 8,055 10,103 11,856 27,781 44,929

Percent of Intervals 0 1 10 25 50 75 90 95 99 100BUSNODEM_COAST 149 376 513 641 881 1,274 2,455 3,589 5,360 5,360BUSNODEM_EAST 97 512 528 692 896 1,363 1,693 1,834 2,571 3,291BUSNODEM_FWEST 222 423 509 576 807 1,270 1,420 1,605 2,098 3,234BUSNODEM_NCENT 0 161 410 582 786 1,216 1,487 1,901 2,615 2,615BUSNODEM_NORTH 146 316 515 608 883 1,313 1,778 1,983 3,221 3,221BUSNODEM_SCENT 231 329 480 699 903 1,296 2,697 3,260 6,032 6,032BUSNODEM_SOUTH 83 440 521 712 952 1,345 2,362 2,729 3,781 3,781BUSNODEM_WEST 50 272 500 708 939 1,369 2,099 2,130 3,258 3,258

BUSNODEM Sub-Total 978 2,829 3,976 5,218 7,047 10,446 15,991 19,031 28,936 30,792

For example: to obtain ±10% Accuracy at 90% Confidence for 50% of the intervals such that all Profile

Type/Weather Zone combinations within those intervals would achieve that level of accuracy would require a sample size increase of 5,703 points for BUSLOLF and 7,047 points for BUSNODEM

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Types and Weather Zones - Within Each Interval

Percent of Intervals 0 1 10 25 50 75 90 95 99 100RESHIWR_COAST 36 160 324 577 856 1,075 1,075 1,199 3,624 3,624RESHIWR_EAST 22 132 338 727 931 1,361 1,386 1,855 3,232 3,232RESHIWR_FWEST 50 192 355 663 929 1,310 1,310 1,644 2,228 2,228RESHIWR_NCENT 0 64 178 583 748 962 973 1,165 1,937 1,937RESHIWR_NORTH 8 133 326 597 932 1,016 1,016 1,289 2,092 2,867RESHIWR_SCENT 6 129 320 597 932 1,172 1,195 1,338 2,200 2,200RESHIWR_SOUTH 18 132 246 600 895 1,085 1,085 1,141 2,095 2,610RESHIWR_WEST 8 126 264 590 875 875 1,075 1,270 2,224 2,224

RESHIWR Sub-Total 148 1,068 2,351 4,934 7,098 8,856 9,115 10,901 19,632 20,922

Percent of Intervals 0 1 10 25 50 75 90 95 99 100RESLOWR_COAST 0 60 151 524 908 950 950 1,490 1,846 1,846RESLOWR_EAST 0 81 282 498 756 934 934 1,119 1,738 1,738RESLOWR_FWEST 19 143 326 584 879 961 961 1,554 2,543 2,543RESLOWR_NCENT 0 45 131 374 575 662 662 873 1,133 1,133RESLOWR_NORTH 0 114 211 419 668 668 741 877 1,034 1,034RESLOWR_SCENT 0 98 187 453 656 805 805 805 1,247 1,247RESLOWR_SOUTH 0 114 248 625 909 1,302 1,583 1,651 2,584 2,584RESLOWR_WEST 0 97 165 549 659 779 779 938 1,728 1,728

RESLOWR Sub-Total 19 752 1,701 4,026 6,010 7,061 7,415 9,307 13,853 13,853

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Types - Within Each Interval

Percent of Intervals 0 1 10 25 50 75 90 95 99 100BUSHILF 0 319 537 626 750 838 1,004 1,088 2,017 2,017BUSMEDLF 7 748 1,300 1,708 2,267 3,031 4,222 4,485 6,986 13,884BUSLOLF 574 2,033 2,850 4,093 5,703 8,055 10,103 11,856 27,781 44,929BUSNODEM 978 2,829 3,976 5,218 7,047 10,446 15,991 19,031 28,936 30,792RESHIWR 148 1,068 2,351 4,934 7,098 8,856 9,115 10,901 19,632 20,922RESLOWR 19 752 1,701 4,026 6,010 7,061 7,415 9,307 13,853 13,853

Total 1,726 7,749 12,715 20,605 28,875 38,287 47,850 56,668 99,205 126,397

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For example: to obtain ±10% Accuracy at 90% Confidence for 1% of the intervals such that all Profile Type/Weather Zone combinations within those intervals would require a sample size increase of 7,749 points

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Option 3• To obtain ±10% Accuracy at 90% Confidence for Intervals Accounting

for Selected Percents of the MWH within Each Profile Type and Weather Zone

Percent of MWh 0 1 5 10 25 50 60 70 75 80 85 90 95 99 100BUSHILF_COAST 0 2 2 2 2 2 2 2 2 8 15 31 61 89 1,211BUSHILF_EAST 0 2 2 2 2 2 14 30 37 46 51 64 77 98 177BUSHILF_FWEST 0 3 3 3 3 3 3 3 3 3 3 3 3 35 180BUSHILF_NCENT 0 1 1 1 1 1 1 1 1 1 3 10 17 42 75BUSHILF_NORTH 0 2 2 2 2 2 2 2 2 2 2 2 6 16 92BUSHILF_SCENT 0 1 1 1 1 1 1 1 1 1 1 1 1 1 73BUSHILF_SOUTH 0 2 2 2 2 2 2 5 10 21 32 48 73 100 162BUSHILF_WEST 0 1 1 1 1 1 1 1 1 1 1 1 1 1 47

BUSHILF Sub-Total 0 14 14 14 14 14 26 45 57 83 108 160 239 382 2,017

Percent of MWh 0 1 5 10 25 50 60 70 75 80 85 90 95 99 100BUSMEDLF_COAST 0 2 2 2 2 2 2 10 17 23 33 43 62 107 1,433BUSMEDLF_EAST 0 2 2 2 2 2 5 16 26 32 42 56 71 112 392BUSMEDLF_FWEST 0 4 4 4 4 4 21 44 53 68 83 103 142 220 7,359BUSMEDLF_NCENT 0 1 1 1 1 1 1 1 1 1 1 1 15 39 214BUSMEDLF_NORTH 0 3 3 3 3 3 16 41 64 93 150 208 280 338 541BUSMEDLF_SCENT 0 3 3 3 3 3 3 3 3 3 3 3 3 3 9BUSMEDLF_SOUTH 0 4 4 4 38 152 205 270 309 363 443 538 713 1,234 3,537BUSMEDLF_WEST 0 3 3 3 3 3 3 3 3 3 3 3 3 24 399

BUSMEDLF Sub-Total 0 22 22 22 56 170 256 388 476 586 758 955 1,289 2,077 13,884

For example: to obtain ±10% Accuracy at 90% Confidence for intervals accounting for 50% of

the BUSMEDLF MWh would require a sample size increase of 170 points

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Percent of MWh 0 1 5 10 25 50 60 70 75 80 85 90 95 99 100BUSLOLF_COAST 0 3 3 3 13 72 103 143 164 191 232 282 392 727 2,550BUSLOLF_EAST 0 2 2 2 2 12 31 55 72 90 109 139 187 284 1,054BUSLOLF_FWEST 0 5 5 18 113 303 400 524 604 708 829 1,025 1,591 16,379 28,262BUSLOLF_NCENT 0 4 4 4 4 60 102 142 170 198 234 285 383 610 6,838BUSLOLF_NORTH 0 4 4 4 4 43 69 97 117 142 175 222 319 541 1,133BUSLOLF_SCENT 0 2 2 2 2 41 66 94 114 134 155 189 242 370 882BUSLOLF_SOUTH 0 2 2 2 2 71 101 138 160 189 232 291 407 690 2,075BUSLOLF_WEST 0 1 1 5 43 115 150 195 230 261 313 376 508 847 2,135

BUSLOLF Sub-Total 0 23 23 40 183 717 1,022 1,388 1,631 1,913 2,279 2,809 4,029 20,448 44,929

Percent of MWh 0 1 5 10 25 50 60 70 75 80 85 90 95 99 100BUSNODEM_COAST 0 5 37 65 144 307 383 450 497 538 589 677 1,087 2,308 5,360BUSNODEM_EAST 0 7 45 64 106 185 235 296 342 398 465 570 758 1,079 3,291BUSNODEM_FWEST 0 1 37 65 135 271 317 372 401 438 477 526 619 888 3,234BUSNODEM_NCENT 0 5 5 5 5 39 125 219 267 317 378 460 610 903 2,615BUSNODEM_NORTH 24 80 116 136 183 264 296 350 378 422 475 548 698 1,089 3,221BUSNODEM_SCENT 21 71 113 136 176 254 303 370 412 472 560 709 1,383 2,544 6,032BUSNODEM_SOUTH 0 43 93 120 180 285 333 398 447 513 609 767 1,113 2,097 3,781BUSNODEM_WEST 2 22 50 70 127 239 290 346 379 420 470 547 717 1,179 3,258

BUSNODEM Sub-Total 47 234 496 661 1,056 1,844 2,282 2,801 3,123 3,518 4,023 4,804 6,985 12,087 30,792

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Percent of MWh 0 1 5 10 25 50 60 70 75 80 85 90 95 99 100RESHIWR_COAST 0 1 12 27 57 124 155 194 219 247 281 330 424 635 3,624RESHIWR_EAST 0 2 12 28 69 155 199 253 288 325 371 440 572 911 3,232RESHIWR_FWEST 0 3 26 40 81 162 197 245 268 304 342 396 490 698 2,228RESHIWR_NCENT 0 1 1 1 1 81 130 189 218 248 287 334 406 549 1,937RESHIWR_NORTH 0 1 10 23 60 129 170 215 237 271 307 358 441 614 2,867RESHIWR_SCENT 0 1 10 23 56 137 180 226 260 295 339 399 509 738 2,200RESHIWR_SOUTH 0 2 6 16 46 107 149 198 224 263 304 361 459 634 2,610RESHIWR_WEST 0 1 3 16 56 122 153 188 214 236 264 306 378 525 2,224

RESHIWR Sub-Total 0 12 80 174 426 1,017 1,333 1,708 1,928 2,189 2,495 2,924 3,679 5,304 20,922

Percent of MWh 0 1 5 10 25 50 60 70 75 80 85 90 95 99 100RESLOWR_COAST 0 2 2 2 2 32 57 88 109 136 166 208 289 500 1,846RESLOWR_EAST 0 1 1 1 15 81 114 156 176 202 229 276 339 482 1,738RESLOWR_FWEST 0 2 13 21 47 95 120 157 177 202 241 294 386 593 2,543RESLOWR_NCENT 0 1 1 1 1 24 49 73 90 107 131 161 209 306 1,133RESLOWR_NORTH 0 3 3 3 25 69 93 127 145 165 190 222 280 391 1,034RESLOWR_SCENT 0 2 2 2 11 63 82 111 128 147 172 203 259 402 1,247RESLOWR_SOUTH 0 3 3 3 17 69 101 152 182 220 266 335 463 752 2,584RESLOWR_WEST 0 3 3 3 28 77 101 131 150 170 195 233 298 441 1,728

RESLOWR Sub-Total 0 17 28 36 146 510 717 995 1,157 1,349 1,590 1,932 2,523 3,867 13,853

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for Selected Percents of the MWH within Each Profile Type

Continues on next slide

Percent of MWh 0 1 5 10 25 50 60 70BUSHILF 0 14 14 14 14 14 26 45BUSMEDLF 0 22 22 22 56 170 256 388BUSLOLF 0 23 23 40 183 717 1,022 1,388BUSNODEM 47 234 496 661 1,056 1,844 2,282 2,801RESHIWR 0 12 80 174 426 1,017 1,333 1,708RESLOWR 0 17 28 36 146 510 717 995

Total 47 323 668 957 1,906 4,322 5,696 7,395

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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 increase of 4,322 points

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for Selected Percents of the MWH within Each Profile Type

Percent of MWh 75 80 85 90 95 99 100BUSHILF 57 83 108 160 239 382 2,017BUSMEDLF 476 586 758 955 1,289 2,077 13,884BUSLOLF 1,631 1,913 2,279 2,809 4,029 20,448 44,929BUSNODEM 3,123 3,518 4,023 4,804 6,985 12,087 30,792RESHIWR 1,928 2,189 2,495 2,924 3,679 5,304 20,922RESLOWR 1,157 1,349 1,590 1,932 2,523 3,867 13,853

Total 8,447 9,718 11,338 13,674 18,839 44,264 126,497

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for Selected Percents of the dollars within each Profile Type & Weather Zone

Percent of Dollars 0 1 5 10 25 50 60 70 75 80 85 90 95 99 100BUSHILF_COAST 0 2 2 2 2 2 2 2 2 4 15 37 68 97 1,211BUSHILF_EAST 0 2 2 2 2 2 4 23 30 37 46 54 67 90 177BUSHILF_FWEST 0 3 3 3 3 3 3 3 3 3 3 3 3 43 180BUSHILF_NCENT 0 1 1 1 1 1 1 1 1 1 8 15 20 42 75BUSHILF_NORTH 0 2 2 2 2 2 2 2 2 2 2 2 6 16 92BUSHILF_SCENT 0 1 1 1 1 1 1 1 1 1 1 1 1 1 73BUSHILF_SOUTH 0 2 2 2 2 2 2 2 5 10 18 32 55 88 162BUSHILF_WEST 0 1 1 1 1 1 1 1 1 1 1 1 1 1 47

BUSHILF Sub-Total 0 14 14 14 14 14 16 35 45 59 94 145 221 378 2,017

Percent of Dollars 0 1 5 10 25 50 60 70 75 80 85 90 95 99 100BUSMEDLF_COAST 0 2 2 2 2 2 2 2 2 10 20 33 51 99 1,433BUSMEDLF_EAST 0 2 2 2 2 2 2 5 11 19 29 42 60 112 392BUSMEDLF_FWEST 0 4 4 4 4 4 4 17 30 44 63 83 120 201 7,359BUSMEDLF_NCENT 0 1 1 1 1 1 1 1 1 1 1 1 15 39 214BUSMEDLF_NORTH 0 3 3 3 3 3 3 13 26 44 72 130 220 312 541BUSMEDLF_SCENT 0 3 3 3 3 3 3 3 3 3 3 3 3 3 9BUSMEDLF_SOUTH 0 4 4 4 38 147 200 252 283 322 384 481 649 1,028 3,537BUSMEDLF_WEST 0 3 3 3 3 3 3 3 3 3 3 3 3 16 399

BUSMEDLF Sub-Total 0 22 22 22 56 165 218 296 359 446 575 776 1,121 1,810 13,884

Note: Dollars = Σ (MWh * MCPE)

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Percent of Dollars 0 1 5 10 25 50 60 70 75 80 85 90 95 99 100BUSLOLF_COAST 0 3 3 3 3 43 72 103 123 148 180 226 301 549 2,550BUSLOLF_EAST 0 2 2 2 2 2 9 35 47 63 85 114 160 259 1,054BUSLOLF_FWEST 0 5 5 5 46 196 289 393 457 542 660 850 1,275 14,530 28,262BUSLOLF_NCENT 0 4 4 4 4 31 69 117 142 170 204 253 333 533 6,838BUSLOLF_NORTH 0 4 4 4 4 19 47 73 92 112 137 175 253 467 1,133BUSLOLF_SCENT 0 2 2 2 2 17 37 62 75 94 119 150 194 294 882BUSLOLF_SOUTH 0 2 2 2 2 43 76 116 132 160 201 258 362 616 2,075BUSLOLF_WEST 0 1 1 1 19 77 105 145 172 206 248 313 421 719 2,135

BUSLOLF Sub-Total 0 23 23 23 82 428 704 1,044 1,240 1,495 1,834 2,339 3,299 17,967 44,929

Percent of Dollars 0 1 5 10 25 50 60 70 75 80 85 90 95 99 100BUSNODEM_COAST 0 5 41 78 175 369 420 473 505 546 589 677 1,144 2,607 5,360BUSNODEM_EAST 0 14 48 68 101 169 207 265 309 356 420 512 692 1,035 3,291BUSNODEM_FWEST 0 1 45 78 177 290 330 372 401 431 469 518 611 857 3,234BUSNODEM_NCENT 0 5 5 5 5 125 199 260 295 340 394 477 619 903 2,615BUSNODEM_NORTH 24 84 121 141 194 264 296 343 378 414 460 524 652 989 3,221BUSNODEM_SCENT 21 71 117 136 181 260 310 363 405 457 527 654 1,075 2,411 6,032BUSNODEM_SOUTH 0 40 97 128 195 309 359 454 513 609 758 1,036 1,735 2,509 3,781BUSNODEM_WEST 2 22 47 70 131 244 290 339 365 399 448 524 673 1,111 3,258

BUSNODEM Sub-Total 47 242 521 704 1,159 2,030 2,411 2,869 3,171 3,552 4,065 4,922 7,201 12,422 30,792

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Percent of Dollars 0 1 5 10 25 50 60 70 75 80 85 90 95 99 100RESHIWR_COAST 0 1 7 17 38 85 116 150 174 199 230 281 362 544 3,624RESHIWR_EAST 0 2 5 17 46 111 145 194 225 264 312 377 485 783 3,232RESHIWR_FWEST 0 3 20 31 63 126 157 202 223 257 298 349 431 620 2,228RESHIWR_NCENT 0 1 1 1 1 27 64 120 150 189 230 287 362 508 1,937RESHIWR_NORTH 0 1 1 10 34 88 120 160 190 221 260 313 392 556 2,867RESHIWR_SCENT 0 1 6 13 37 92 129 175 200 232 277 339 427 640 2,200RESHIWR_SOUTH 0 2 2 11 32 76 107 149 178 213 251 310 402 576 2,610RESHIWR_WEST 0 1 1 6 30 85 113 149 173 193 225 264 338 471 2,224

RESHIWR Sub-Total 0 12 43 106 281 690 951 1,299 1,513 1,768 2,083 2,520 3,199 4,698 20,922

Percent of Dollars 0 1 5 10 25 50 60 70 75 80 85 90 95 99 100RESLOWR_COAST 0 2 2 2 2 8 26 49 64 88 113 156 219 396 1,846RESLOWR_EAST 0 1 1 1 7 51 85 118 141 166 196 235 301 437 1,738RESLOWR_FWEST 0 2 7 16 37 71 95 120 143 162 192 241 326 535 2,543RESLOWR_NCENT 0 1 1 1 1 1 11 38 53 73 94 121 171 268 1,133RESLOWR_NORTH 0 3 3 3 14 45 66 93 114 131 160 190 245 350 1,034RESLOWR_SCENT 0 2 2 2 2 32 52 78 90 111 133 162 219 340 1,247RESLOWR_SOUTH 0 3 3 3 6 40 61 97 123 157 203 266 383 651 2,584RESLOWR_WEST 0 3 3 3 11 48 69 97 114 131 155 190 250 384 1,728

RESLOWR Sub-Total 0 17 22 31 80 296 465 690 842 1,019 1,246 1,561 2,114 3,361 13,853

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for Selected Percents of the dollars within each Profile Type


% of Dollars 0 1 5 10 25 50 60 70BUSHILF 0 14 14 14 14 14 16 35BUSMEDLF 0 22 22 22 56 165 218 296BUSLOLF 0 23 23 23 82 428 704 1,044BUSNODEM 47 242 521 704 1,159 2,030 2,411 2,869RESHIWR 0 12 43 106 281 690 951 1,299RESLOWR 0 17 22 31 80 296 465 690

Total 47 331 650 910 1,697 3,673 4,825 6,303

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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 increase of 3,673 points

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for Selected Percents of the dollars within each Profile Type

% of Dollars 75 80 85 90 95 99 100BUSHILF 45 59 94 145 221 378 2,017BUSMEDLF 359 446 575 776 1,121 1,810 13,884BUSLOLF 1,240 1,495 1,834 2,339 3,299 17,967 44,929BUSNODEM 3,171 3,552 4,065 4,922 7,201 12,422 30,792RESHIWR 1,513 1,768 2,083 2,520 3,199 4,698 20,922RESLOWR 842 1,019 1,246 1,561 2,114 3,361 13,853

Total 7,245 8,419 9,982 12,353 17,250 40,735 126,497

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Precision vs Sample Size

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

0

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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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Class Level MWH & Dollars

Annual MWh * MCPE % - Profile Total %Profile / Wzone Annual MWh (Dollars) Annual MWh Annual MWh * MCPE LWAP

BUSHILF_COAST 4,323,841 286,069,211 30.2% 30.4% 66.16BUSHILF_EAST 489,464 32,213,760 3.4% 3.4% 65.81BUSHILF_FWEST 775,977 48,892,306 5.4% 5.2% 63.01BUSHILF_NCENT 6,388,635 426,223,889 44.6% 45.3% 66.72BUSHILF_NORTH 380,942 25,014,049 2.7% 2.7% 65.66BUSHILF_SCENT 232,398 15,354,768 1.6% 1.6% 66.07BUSHILF_SOUTH 1,388,157 85,633,911 9.7% 9.1% 61.69BUSHILF_WEST 334,103 21,810,574 2.3% 2.3% 65.28BUSHILF Sub-Total 14,313,518 941,212,466 100.0% 100.0% 65.76

BUSMEDLF_COAST 7,929,541 566,400,403 32.1% 32.3% 71.43BUSMEDLF_EAST 823,991 57,829,866 3.3% 3.3% 70.18BUSMEDLF_FWEST 791,679 53,869,510 3.2% 3.1% 68.04BUSMEDLF_NCENT 11,200,703 808,001,368 45.4% 46.1% 72.14BUSMEDLF_NORTH 631,980 44,665,588 2.6% 2.5% 70.68BUSMEDLF_SCENT 381,072 27,461,640 1.5% 1.6% 72.06BUSMEDLF_SOUTH 2,308,720 150,822,055 9.4% 8.6% 65.33BUSMEDLF_WEST 597,822 42,849,139 2.4% 2.4% 71.68BUSMEDLF Sub-Total 24,665,508 1,751,899,568 100.0% 100.0% 71.03

Not all Profile Type / Weather Zone Combinations are created equal in either MWh or Total Dollars (ΣMWh * MCPE) !

23



BUSLOLF_COAST 5,561,754 411,835,035 34.5% 34.4% 74.05BUSLOLF_EAST 709,293 52,276,533 4.4% 4.4% 73.70BUSLOLF_FWEST 599,240 43,819,758 3.7% 3.7% 73.13BUSLOLF_NCENT 6,268,393 480,406,912 38.9% 40.1% 76.64BUSLOLF_NORTH 494,662 36,570,065 3.1% 3.1% 73.93BUSLOLF_SCENT 252,484 18,806,895 1.6% 1.6% 74.49BUSLOLF_SOUTH 1,744,996 118,790,022 10.8% 9.9% 68.07BUSLOLF_WEST 482,615 35,935,575 3.0% 3.0% 74.46

BUSLOLF Sub-Total 16,113,437 1,198,440,795 100.0% 100.0% 74.38

BUSNODEM_COAST 1,095,942 69,352,578 39.9% 39.4% 63.28BUSNODEM_EAST 146,217 9,789,863 5.3% 5.6% 66.95BUSNODEM_FWEST 117,532 7,534,145 4.3% 4.3% 64.10BUSNODEM_NCENT 1,054,705 67,897,593 38.4% 38.5% 64.38BUSNODEM_NORTH 104,705 7,050,056 3.8% 4.0% 67.33BUSNODEM_SCENT 54,159 3,575,891 2.0% 2.0% 66.03BUSNODEM_SOUTH 85,280 5,541,061 3.1% 3.1% 64.98BUSNODEM_WEST 86,399 5,392,726 3.1% 3.1% 62.42

BUSNODEM Sub-Total 2,744,939 176,133,912 100.0% 100.0% 64.17


24



RESHIWR_COAST 5,183,399 375,843,307 21.7% 22.0% 72.51RESHIWR_EAST 1,189,789 83,615,228 5.0% 4.9% 70.28RESHIWR_FWEST 613,825 41,948,961 2.6% 2.5% 68.34RESHIWR_NCENT 13,248,842 951,723,293 55.4% 55.8% 71.83RESHIWR_NORTH 846,446 59,284,584 3.5% 3.5% 70.04RESHIWR_SCENT 363,108 25,890,925 1.5% 1.5% 71.30RESHIWR_SOUTH 1,824,794 120,921,521 7.6% 7.1% 66.27RESHIWR_WEST 648,246 45,617,470 2.7% 2.7% 70.37

RESHIWR Sub-Total 23,918,447 1,704,845,289 100.0% 100.0% 71.28

RESLOWR_COAST 21,482,103 1,714,607,553 41.4% 42.7% 79.82RESLOWR_EAST 1,594,694 118,260,609 3.1% 2.9% 74.16RESLOWR_FWEST 1,130,612 84,278,039 2.2% 2.1% 74.54RESLOWR_NCENT 19,038,264 1,486,826,492 36.7% 37.0% 78.10RESLOWR_NORTH 1,105,198 82,940,166 2.1% 2.1% 75.05RESLOWR_SCENT 1,020,813 78,785,112 2.0% 2.0% 77.18RESLOWR_SOUTH 5,465,502 372,690,210 10.5% 9.3% 68.19RESLOWR_WEST 1,066,991 79,351,474 2.1% 2.0% 74.37

RESLOWR Sub-Total 51,904,178 4,017,739,656 100.0% 100.0% 77.41


25



BUSHILF Sub-Total 14,313,518 941,212,466 10.7% 9.6% 65.76BUSMEDLF Sub-Total 24,665,508 1,751,899,568 18.5% 17.9% 71.03BUSLOLF Sub-Total 16,113,437 1,198,440,795 12.1% 12.2% 74.38BUSNODEM Sub-Total 2,744,939 176,133,912 2.1% 1.8% 64.17RESHIWR Sub-Total 23,918,447 1,704,845,289 17.9% 17.4% 71.28RESLOWR Sub-Total 51,904,178 4,017,739,656 38.8% 41.0% 77.41

Total 133,660,027 9,790,271,686 100.0% 100.0% 73.25

• Totals from previous three slides.

Is accuracy more important for RESLOWR (41% of Dollars) than for BUSNODEM (2.1% of Dollars)?

26

Class Level MWH & Dollars - Descending Order by Dollars

* Note: Dollars = Σ (MWh * MCPE)

Annual Cumlt. Cumlt.% Cumlt. Cumlt.%rank Profile / Wzone MWh Dollars* MWh Ttl MWh Dollars Ttl Dollars

1 RESLOWR_COAST 21,482,103 1,714,607,553 21,482,103 16% 1,714,607,553 18%2 RESLOWR_NCENT 19,038,264 1,486,826,492 40,520,368 30% 3,201,434,045 33%3 RESHIWR_NCENT 13,248,842 951,723,293 53,769,210 40% 4,153,157,338 42%4 BUSMEDLF_NCENT 11,200,703 808,001,368 64,969,913 49% 4,961,158,706 51%5 BUSMEDLF_COAST 7,929,541 566,400,403 72,899,455 55% 5,527,559,109 56%6 BUSLOLF_NCENT 6,268,393 480,406,912 79,167,848 59% 6,007,966,022 61%7 BUSHILF_NCENT 6,388,635 426,223,889 85,556,483 64% 6,434,189,911 66%8 BUSLOLF_COAST 5,561,754 411,835,035 91,118,237 68% 6,846,024,946 70%

9 RESHIWR_COAST 5,183,399 375,843,307 96,301,636 72% 7,221,868,253 74%10 RESLOWR_SOUTH 5,465,502 372,690,210 101,767,138 76% 7,594,558,463 78%11 BUSHILF_COAST 4,323,841 286,069,211 106,090,979 79% 7,880,627,673 80%12 BUSMEDLF_SOUTH 2,308,720 150,822,055 108,399,699 81% 8,031,449,728 82%13 RESHIWR_SOUTH 1,824,794 120,921,521 110,224,492 82% 8,152,371,250 83%14 BUSLOLF_SOUTH 1,744,996 118,790,022 111,969,488 84% 8,271,161,271 84%15 RESLOWR_EAST 1,594,694 118,260,609 113,564,182 85% 8,389,421,881 86%16 BUSHILF_SOUTH 1,388,157 85,633,911 114,952,339 86% 8,475,055,792 87%


Top 4 classes account for 49% of the MWh and 51% of the dollars

27


* Dollars = Annual MWh * MCPE Continues on next slide

Annual Cumlt. Cumlt.% Cumlt. Cumlt.%rank Profile / Wzone MWh Dollars* MWh Ttl MWh Dollars Ttl Dollars17 RESLOWR_FWEST 1,130,612 84,278,039 116,082,951 87% 8,559,333,831 87%18 RESHIWR_EAST 1,189,789 83,615,228 117,272,739 88% 8,642,949,058 88%19 RESLOWR_NORTH 1,105,198 82,940,166 118,377,937 89% 8,725,889,225 89%20 RESLOWR_WEST 1,066,991 79,351,474 119,444,929 89% 8,805,240,698 90%21 RESLOWR_SCENT 1,020,813 78,785,112 120,465,742 90% 8,884,025,811 91%22 BUSNODEM_COAST 1,095,942 69,352,578 121,561,684 91% 8,953,378,389 91%23 BUSNODEM_NCENT 1,054,705 67,897,593 122,616,389 92% 9,021,275,982 92%24 RESHIWR_NORTH 846,446 59,284,584 123,462,835 92% 9,080,560,566 93%25 BUSMEDLF_EAST 823,991 57,829,866 124,286,825 93% 9,138,390,432 93%26 BUSMEDLF_FWEST 791,679 53,869,510 125,078,504 94% 9,192,259,942 94%27 BUSLOLF_EAST 709,293 52,276,533 125,787,797 94% 9,244,536,474 94%28 BUSHILF_FWEST 775,977 48,892,306 126,563,774 95% 9,293,428,780 95%29 RESHIWR_WEST 648,246 45,617,470 127,212,021 95% 9,339,046,250 95%30 BUSMEDLF_NORTH 631,980 44,665,588 127,844,001 96% 9,383,711,838 96%31 BUSLOLF_FWEST 599,240 43,819,758 128,443,242 96% 9,427,531,596 96%32 BUSMEDLF_WEST 597,822 42,849,139 129,041,064 97% 9,470,380,735 97%

28


* Dollars = Annual MWh * MCPE Continues on next slide

Annual Cumlt. Cumlt.% Cumlt. Cumlt.%rank Profile / Wzone MWh Dollars* MWh Ttl MWh Dollars Ttl Dollars33 RESHIWR_FWEST 613,825 41,948,961 129,654,888 97% 9,512,329,696 97%34 BUSLOLF_NORTH 494,662 36,570,065 130,149,550 97% 9,548,899,761 98%35 BUSLOLF_WEST 482,615 35,935,575 130,632,165 98% 9,584,835,336 98%36 BUSHILF_EAST 489,464 32,213,760 131,121,629 98% 9,617,049,096 98%37 BUSMEDLF_SCENT 381,072 27,461,640 131,502,701 98% 9,644,510,736 99%38 RESHIWR_SCENT 363,108 25,890,925 131,865,808 99% 9,670,401,660 99%

39 BUSHILF_NORTH 380,942 25,014,049 132,246,750 99% 9,695,415,709 99%40 BUSHILF_WEST 334,103 21,810,574 132,580,853 99% 9,717,226,283 99%41 BUSLOLF_SCENT 252,484 18,806,895 132,833,337 99% 9,736,033,178 99%42 BUSHILF_SCENT 232,398 15,354,768 133,065,735 100% 9,751,387,946 100%43 BUSNODEM_EAST 146,217 9,789,863 133,211,953 100% 9,761,177,809 100%44 BUSNODEM_FWEST 117,532 7,534,145 133,329,485 100% 9,768,711,954 100%45 BUSNODEM_NORTH 104,705 7,050,056 133,434,189 100% 9,775,762,009 100%46 BUSNODEM_SOUTH 85,280 5,541,061 133,519,469 100% 9,781,303,070 100%47 BUSNODEM_WEST 86,399 5,392,726 133,605,868 100% 9,786,695,796 100%48 BUSNODEM_SCENT 54,159 3,575,891 133,660,027 100% 9,790,271,686 100%

29

Options 5 & 6

• These options iteratively allocate increments of 10 sample points to the next Profile Type / Weather Zone Combination in order to produce the most gain in

– reducing MWh (Option 5) estimation error (Precision × MWh) summed across all intervals

– reducing Dollar (option 6) 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 10 sample points, and the diminishing return on that improvement

30

Option 5 – MWh Error Reduction Optimization

Sample Size Increase 1000 2000 3000 4000 5000 6000 7000

BUSHILF_COAST 30 60 80 110 130 160 180BUSHILF_EAST 0 0 0 10 10 20 30BUSHILF_FWEST 0 0 0 0 0 0 0BUSHILF_NCENT 30 70 100 130 160 190 220BUSHILF_NORTH 0 0 0 0 0 0 0BUSHILF_SCENT 0 0 0 0 0 0 0BUSHILF_SOUTH 0 0 10 20 40 50 60BUSHILF_WEST 0 0 0 0 0 0 0BUSMEDLF_COAST 50 110 160 210 260 300 350BUSMEDLF_EAST 0 0 0 0 10 20 30BUSMEDLF_FWEST 0 0 0 0 0 0 0BUSMEDLF_NCENT 50 120 190 250 310 370 430BUSMEDLF_NORTH 0 0 0 0 0 0 10BUSMEDLF_SCENT 0 0 0 0 0 0 0BUSMEDLF_SOUTH 0 40 80 110 150 180 210BUSMEDLF_WEST 0 0 0 0 0 0 0BUSLOLF_COAST 40 110 170 220 280 330 390BUSLOLF_EAST 0 0 0 0 0 0 0BUSLOLF_FWEST 0 0 0 0 0 0 0BUSLOLF_NCENT 40 110 170 230 290 350 410BUSLOLF_NORTH 0 0 0 0 0 0 0BUSLOLF_SCENT 0 0 0 0 0 0 0BUSLOLF_SOUTH 0 0 0 20 50 70 100BUSLOLF_WEST 0 0 0 0 0 0 0BUSNODEM_COAST 0 0 20 50 70 90 120BUSNODEM_EAST 0 0 0 0 0 0 0BUSNODEM_FWEST 0 0 0 0 0 0 0BUSNODEM_NCENT 0 0 0 0 0 0 0BUSNODEM_NORTH 0 0 0 0 0 0 0BUSNODEM_SCENT 0 0 0 0 0 0 0BUSNODEM_SOUTH 0 0 0 0 0 10 10BUSNODEM_WEST 0 0 0 0 0 0 0RESHIWR_COAST 90 160 210 260 310 360 410RESHIWR_EAST 10 30 50 70 100 120 140RESHIWR_FWEST 0 0 20 30 40 60 70RESHIWR_NCENT 150 270 380 480 580 680 780RESHIWR_NORTH 0 10 30 50 60 80 90RESHIWR_SCENT 0 0 0 10 20 30 40RESHIWR_SOUTH 20 50 80 110 130 160 180RESHIWR_WEST 0 0 10 20 40 50 60RESLOWR_COAST 230 380 500 610 720 840 960RESLOWR_EAST 0 20 40 70 90 110 130RESLOWR_FWEST 0 10 30 50 70 90 100RESLOWR_NCENT 190 320 430 530 640 740 840RESLOWR_NORTH 0 0 20 40 60 70 90RESLOWR_SCENT 0 0 10 30 40 60 80RESLOWR_SOUTH 70 130 190 240 290 340 390RESLOWR_WEST 0 0 20 40 50 70 90

Percent Reduction MWh Error 27.5% 37.4% 43.6% 48.1% 51.6% 54.4% 56.7%

Iterative Sample Allocation toMaximize MWh Error Reduction

0%

10%

20%

30%

40%

50%

60%

70%

0 2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000

Sample Size

MW

h E

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r R

edu

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%)

Cumulative sample sizes are shown in increments of 1,000; they were determined iteratively in increments of 10 sample points as additions to the current sample size.

31

Option 6 – Dollar Error Reduction Optimization


BUSHILF_COAST 20 50 80 100 130 150 180BUSHILF_EAST 0 0 0 10 10 20 20BUSHILF_FWEST 0 0 0 0 0 0 0BUSHILF_NCENT 40 70 100 130 160 190 220BUSHILF_NORTH 0 0 0 0 0 0 0BUSHILF_SCENT 0 0 0 0 0 0 0BUSHILF_SOUTH 0 0 10 20 30 40 50BUSHILF_WEST 0 0 0 0 0 0 0BUSMEDLF_COAST 50 110 160 210 250 300 350BUSMEDLF_EAST 0 0 0 0 0 20 30BUSMEDLF_FWEST 0 0 0 0 0 0 0BUSMEDLF_NCENT 50 120 190 250 320 380 440BUSMEDLF_NORTH 0 0 0 0 0 0 0BUSMEDLF_SCENT 0 0 0 0 0 0 0BUSMEDLF_SOUTH 0 40 70 110 140 170 200BUSMEDLF_WEST 0 0 0 0 0 0 0BUSLOLF_COAST 40 110 170 230 280 340 390BUSLOLF_EAST 0 0 0 0 0 0 0BUSLOLF_FWEST 0 0 0 0 0 0 0BUSLOLF_NCENT 40 120 190 250 310 380 440BUSLOLF_NORTH 0 0 0 0 0 0 0BUSLOLF_SCENT 0 0 0 0 0 0 0BUSLOLF_SOUTH 0 0 0 10 40 70 90BUSLOLF_WEST 0 0 0 0 0 0 0BUSNODEM_COAST 0 0 20 50 70 90 120BUSNODEM_EAST 0 0 0 0 0 0 0BUSNODEM_FWEST 0 0 0 0 0 0 0BUSNODEM_NCENT 0 0 0 0 0 0 0BUSNODEM_NORTH 0 0 0 0 0 0 0BUSNODEM_SCENT 0 0 0 0 0 0 0BUSNODEM_SOUTH 0 0 0 0 10 10 10BUSNODEM_WEST 0 0 0 0 0 0 0RESHIWR_COAST 90 150 210 260 310 360 410RESHIWR_EAST 10 30 50 70 90 110 130RESHIWR_FWEST 0 0 10 30 40 50 70RESHIWR_NCENT 140 260 360 460 560 660 750RESHIWR_NORTH 0 10 30 40 60 70 90RESHIWR_SCENT 0 0 0 10 20 20 30RESHIWR_SOUTH 20 50 70 100 120 140 170RESHIWR_WEST 0 0 10 20 30 50 60RESLOWR_COAST 240 390 520 640 760 880 1000RESLOWR_EAST 0 20 50 70 90 120 140RESLOWR_FWEST 0 10 30 50 70 90 110RESLOWR_NCENT 200 330 440 550 660 760 870RESLOWR_NORTH 0 10 20 40 60 80 90RESLOWR_SCENT 0 0 20 30 50 60 80RESLOWR_SOUTH 60 120 170 220 270 320 370RESLOWR_WEST 0 0 20 40 60 70 90

Percent Reduction Dollar Error 27.8% 37.7% 44.0% 48.5% 51.9% 54.7% 57.0%

Iterative Sample Allocation toMaximize Dollar Error Reduction

0%

10%

20%

30%

40%

50%

60%

70%

80%

0 2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000

Sample Size

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Err

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uct

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(%

)

32

Option 5 with Collapsed Profiles/Weather Zones


BUSHILF: COAST, EAST, SCENT, SOUTH 0 0 70 120 170 230 310BUSHILF: FWEST, NCENT, NORTH, WEST 0 0 0 50 110 160 240

BUSMEDLF: COAST, EAST, SCENT, SOUTH 0 10 140 250 360 480 500BUSMEDLF: FWEST, NCENT, NORTH, WEST 0 0 20 130 240 370 500

BUSLOLF: COAST, EAST, SCENT, SOUTH 0 0 30 140 250 380 500BUSLOLF: FWEST, NCENT, NORTH, WEST 0 0 0 100 210 330 500BUSNODEM: ALL ZONES 0 0 0 0 0 0 0RESHIWR_COAST 120 210 310 390 470 500 500RESHIWR_EAST 20 50 90 130 160 190 240RESHIWR_FWEST 0 20 40 60 80 110 140RESHIWR_NCENT 200 380 500 500 500 500 500RESHIWR_NORTH 0 30 60 90 110 140 170RESHIWR: SCENT, WEST 0 0 20 50 80 110 150RESHIWR_SOUTH 40 80 130 170 210 250 310RESLOWR_COAST 290 490 500 500 500 500 500RESLOWR_EAST 0 40 90 120 160 200 250RESLOWR_FWEST 0 30 70 100 130 160 200RESLOWR_NCENT 240 420 500 500 500 500 500RESLOWR_NORTH 0 20 50 80 110 140 170RESLOWR_SCENT 0 10 40 70 90 120 150RESLOWR_SOUTH 90 190 290 370 450 500 500RESLOWR_WEST 0 20 50 80 110 130 170

Percent Reduction MWh Error 32.0% 40.9% 46.0% 49.3% 51.8% 53.8% 55.3%

Iterative Sample Allocation toMaximize MWh Error Reduction

0%

10%

20%

30%

40%

50%

60%

70%

0 2,000 4,000 6,000 8,000 10,000 12,000

Sample Size

MW

h E

rro

r R

edu

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n (

%)

Collapse classes to reduce the number for which the few or no additional sample points are required.

BUSNODEM would no additional points.

33

Option 6 with Collapsed Profiles/Weather Zones


BUSHILF: COAST, EAST, SCENT, SOUTH 0 0 60 110 160 220 290BUSHILF: FWEST, NCENT, NORTH, WEST 0 0 10 60 120 180 260

BUSMEDLF: COAST, EAST, SCENT, SOUTH 0 10 140 250 360 470 500BUSMEDLF: FWEST, NCENT, NORTH, WEST 0 0 30 140 260 370 500

BUSLOLF: COAST, EAST, SCENT, SOUTH 0 0 30 150 260 380 500BUSLOLF: FWEST, NCENT, NORTH, WEST 0 0 0 120 240 360 500BUSNODEM: ALL ZONES 0 0 0 0 0 0 0RESHIWR_COAST 120 210 300 380 460 500 500RESHIWR_EAST 20 50 90 120 150 190 230RESHIWR_FWEST 0 10 40 60 80 100 130RESHIWR_NCENT 190 370 500 500 500 500 500RESHIWR_NORTH 0 30 60 80 110 130 170RESHIWR: SCENT, WEST 0 0 20 50 70 100 140RESHIWR_SOUTH 30 70 120 160 190 230 290RESLOWR_COAST 300 500 500 500 500 500 500RESLOWR_EAST 10 50 90 130 160 200 260RESLOWR_FWEST 0 30 70 100 130 160 210RESLOWR_NCENT 250 440 500 500 500 500 500RESLOWR_NORTH 0 20 60 90 110 140 180RESLOWR_SCENT 0 20 50 70 100 130 160RESLOWR_SOUTH 80 170 270 350 430 500 500RESLOWR_WEST 0 20 60 80 110 140 180

Percent Reduction Dollar Error 32.3% 41.2% 46.1% 49.4% 51.8% 53.8% 55.3%

Iterative Sample Allocation toMaximize Dollar Error Reduction

0%

10%

20%

30%

40%

50%

60%

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0 2,000 4,000 6,000 8,000 10,000 12,000

Sample Size

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uct

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(%

)

34

Conclusions and Follow-up Analysis

• The iterative sample point allocation process has some intuitive appeal– Seems to allocate sample points where they do the

most good– Maximizes UFE reduction

• However,– How does UFE allocation affect the final accuracy?– If the iterative allocation process is used, will we end

up with more or less accurate estimates when they are adjusted for UFE?

– ERCOT will try some Monte Carlo simulations to explore this question

1 ercot lrs precision analysis pwg presentation june 28, 2006

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