Review of Abnormal MCPEs

April 19th through April 27th, 2004

May 12th, 2004Market Operations Support

Brandon Whittle

April 19th, 2004

• MCPEs• NH

Shadow Prices

Interval Ending MCPE        Shadow

Price

00-Jan-00 NORTH SOUTH WEST HOUSTON NORTHEAST N-H

15:15 $39.99 $63.68 $42.48 $80.11 $40.36 $112.00

15:30 $39.99 $78.94 $44.09 $105.95 $40.60 $185.00

15:45 $39.99 $77.04 $43.89 $102.74 $40.57 $176.00

16:00 $37.30 $200.77 $54.49 $314.15 $39.86 $774.00

16:15 $33.23 $226.03 $53.51 $359.73 $36.24 $913.00

16:30 $37.63 $44.30 $38.33 $48.93 $37.73 $32.00

16:45 $39.00 $44.51 $39.58 $48.33 $39.09 $26.00

17:00 $39.99 $45.92 $40.61 $50.03 $40.08 $28.00

April 19th, 2004

• No Limit Changes on NH CSC• Operator Actions consistent with procedures, no

evidence of over or under constraint• Flow controlled to 85-90% of posted limit – Why?

•Blue – NH Limit

•Red – NH Flow

• Why were flows managed fairly conservatively?

– TDSP notified ERCOT of need for lower limit due to post-contingency voltage instability

– ERCOT currently does not have tools to perform real-time voltage stability testing. (Release 3)

– ERCOT Operations chose to be conservative and controlled to a lower than posted limit

• New procedures being discussed to change posted limit

April 19th, 2004

April 19th, 2004Interval Zone Cleared UBES Bid UBES Cleared DBES Bid DBES

1545 HOUSTON2004 349 509 0 2763

1545 NORTH2004 468 1382 899 3455

1545 NORTHEAST2004 110 400 110 2993

1545 SOUTH2004 399 617 97 581

1545 WEST2004 63 357 0 1171

1545 ERCOT TOTAL 1389 3265 1106 10963

1600 HOUSTON2004 508 509 0 2763

1600 NORTH2004 458 1382 1000 3455

1600 NORTHEAST2004 110 400 110 2993

1600 SOUTH2004 399 617 9 581

1600 WEST2004 116 357 0 1171

1600 ERCOT TOTAL 1591 3265 1119 10963

1615 HOUSTON2004 555 606 0 2621

1615 NORTH2004 302 1397 908 3514

1615 NORTHEAST2004 110 515 160 2858

1615 SOUTH2004 514 617 16 587

1615 WEST2004 164 361 0 1171

1615 ERCOT TOTAL 1645 3496 1084 10751

April 19th, 2004

• Contributing Factor – Load Change– 200 MW load forecast increase in ERCOT between 15:45

and 16:00– 229 MW load forecast increase in load in Houston Zone– This causes the predicted flow across the N-H CSC to be

significantly higher, requiring more BES to be cleared, thus higher prices

• CSC flowcsc=

zone

zonezonezone rShiftFactoduledEnergyScheLoadForecasted

April 19th, 2004

Interval ZoneGeneration Scheduled

Interval Forecast

Int. Forecast with Offset Actual Load

Day Ahead Forecast 1600

Day Ahead Forecast 0600

1545 HOUSTON2004 7076 10377 10511 10616 10126 10062

1545 NORTH2004 11619 11626 11776 11642 12275 12145

1545 NORTHEAST2004 3453 751 761 747 731 726

1545 SOUTH2004 9018 8457 8566 8511 8279 8287

1545 WEST2004 2451 2257 2286 2234 2241 2238

1545 ERCOT TOTAL 33617 33468 33900 33750 33652 33458

1600 HOUSTON2004 7083 10668 10740 10666 10232 10192

1600 NORTH2004 11604 11646 11725 11690 12383 12279

1600 NORTHEAST2004 3468 761 766 749 740 735

1600 SOUTH2004 9022 8547 8605 8537 8395 8437

1600 WEST2004 2451 2248 2263 2242 2267 2265

1600 ERCOT TOTAL 33628 33870 34099 33884 34017 33908

1615 HOUSTON2004 7117 10727 10820 10712 10232 10192

1615 NORTH2004 11661 11729 11831 11667 12383 12279

1615 NORTHEAST2004 3570 757 764 757 740 735

1615 SOUTH2004 8967 8594 8668 8554 8395 8437

1615 WEST2004 2474 2248 2267 2248 2267 2265

1615 ERCOT TOTAL 33789 34055 34350 33938 34017 33908

April 22nd, 2004

• MCPEs• NH, SH Shadow Prices

Interval Ending MCPE         Shadow Prices  

00-Jan-00 NORTH SOUTH WEST HOUSTON NORTHEAST NH SH

06:45 $49.41 $49.41 $49.41 $49.41 $49.41 $0.00 $0.00

07:00 $25.13 $250.00 $147.67 $103.87 $290.01 $220.25 $0.00

07:15 $38.68 $41.58 $38.98 $43.59 $38.72 $13.74 $0.00

10:30 $55.58 $55.58 $55.58 $55.58 $55.58 $0.00 $0.00

10:45 $141.92 $101.71 -$298.00 $299.00 $5.00 $439.38 $500.61

11:00 $53.01 $53.99 $53.11 $54.67 $53.03 $4.63 $0.00

13:45 $66.24 $66.24 $66.24 $66.24 $66.24 $0.00 $0.00

14:00 $174.45 $77.12 -$85.50 $196.72 $55.58 $62.29 $303.48

14:15 $196.28 $103.27 -$999.01 $276.00 $14.10 $222.99 $438.29

14:30 $66.34 $47.10 $64.15 $83.50 $65.96 $0.00 $92.36

April 22nd, 2004

• Interval 14:15 West MCPE -999.01 – Extremely high Shadow Prices and MCPEs were

mitigated after market clearing. Prices shown are mitigated prices which are marginal bids cleared.

– All available BES is used to solve a zonal constraint if necessary, using power balance as a limit.

– Due to exhaustion of available bid stacks and West Zone BES bid of -999.01

April 22nd, 2004

April 22nd, 2004•Blue – NH Limit

•Red – NH Flow

April 22nd, 2004

• Significant Limit change on N-H for 0700– Related to planned outage of King to Kuykendall

• NH and SH constraints active, in both cases Houston UBES is necessary to solve– N-H curtailment contributes to loading on SH constraint

• Operator actions – No evidence of over constraint– Operator could have mitigated by easing into the limit

change although not supported in procedures

• New Development in Procedures– ERCOT recognized problem and proposed

internal solution– Solution in Transmission and Security Desk

Procedures 2.2.1 step 2.2• Operator is to gradually reduce flows across a CSC in

preparation for a limit change

April 22nd, 2004

April 26th, 2004

Interval Ending MCPE        

00-Jan-00 NORTH SOUTH WEST HOUSTON NORTHEAST

16:30 $99.26 $99.26 $99.26 $99.26 $99.26

16:45 $194.95 $194.95 $194.95 $194.95 $194.95

17:00 $89.59 $89.59 $89.59 $89.59 $89.59

•MCPEs

•1645 Interval high, no congestion

April 26th, 2004

•1606 Generation Trip

•Low Frequency

•Increase in Balancing Energy necessary to replace RRS deployment

•Blue – ERCOT Frequency

•Red – Balancing deployed

April 27th, 2004

• MCPEs• Shadow Prices Northeast to North

Interval Ending Price         Shadow Price

27-Apr-04 NORTH SOUTH WEST HOUSTON NORTHEAST E-N

16:00 $129.76 $126.23 $116.04 $128.02 $29.29 $242.10

16:15 $290.01 $280.79 $254.22 $285.46 $28.04 $631.25

16:30 $92.39 $90.33 $84.41 $91.38 $33.99 $140.72

16:45 $87.14 $85.27 $79.88 $86.22 $33.99 $128.08

17:00 $71.05 $71.05 $71.05 $71.05 $71.05 $0.00

April 27th, 2004

•Blue – EN Limit

•Red – EN Flow

April 27th, 2004

• Operator Actions were good, let off constraint as flow decreased

• Limits were lowered on NE-N due to a combination of several outages

• Increase in Balancing required to meet load contributed to rise in MCPEs

Recommendations

• Ease into planned CSC limit changes– Requires procedure change – DONE

• Post limits CSC limits in Real Time– In discussion, enhancements to made progressively

• Enhance BES market to limit use of zones with negligible affect on constraint solution– Currently planned for Release 5– Requires Protocol changes– Solutions currently being studied

• Shadow Price Cap?• Virtual Bids?• Penalty Weight Change?