Graph Trend Definitions

• Telemetered SCE: Sum of all QSE’s Telemetered SCE (uses “Left” scale).• Regulation Deployed: Sum of all Regulation Ancillary Service. PLUS = increase

generation, MINUS = decrease generation. (uses “Left” scale).• Responsive Deployed: Sum of all Responsive Ancillary Service. Positive Only. (uses

“Left” scale).• Balancing:Balancing awarded: Sum of all QSE’s award. (uses “Left” scale)• Spinning Reserve: Sum of all QSE’s telemetered Spinning Reserves. (uses “Left” scale.)• Total Generation: Sum of all QSE’s “Total Generation” telemetered to ERCOT. (On

some NOI’s this may include bilateral purchases/sells). (uses “Right” scale.)• BPS & Dynamic: Sum of all QSE’s Base Power Schedules and Dynamic Schedules.

Most QSE’s have one or the other, some have both. (uses “Right” scale).• OLC “On-Line Capacity”: Sum of all QSE’s – Sum of Total Generation and Spinning

Reserve as telemetered from each QSE. (uses “Right” scale).• Obligation – Total Up Physical Obligation: Sum of all QSE’s. Sums for each QSE:

Base Power Schedule, Dynamic Schedule, Regulation “UP” Physical obligation, Responsive Physical obligation, any Non-Spin that has been deployed, Balancing Energy Deployed and Frequency Obligation (QSE bias times frequency deviation). (uses “Right” scale).

• Excess: Difference between “OLC” and “Obligation”: Sum for all QSE’s. MINUS = QSE’s “deficit” (uses Right scale).

• Load Imbalance: Difference between “Total Generation” and the sum of “Base Power Schedules and Dynamic Schedules”. (uses “Left” scale)

-3000

-2000

-1000

0

1000

2000

3000

4000

5000

6000

7000

8000

6:00 6:05 6:10 6:15 6:20 6:25 6:30 6:35 6:40 6:45 6:50 6:55 7:00 7:05 7:10 7:15 7:20 7:25 7:30 7:35 7:40 7:45 7:50 7:55 8:00

26000

28000

30000

32000

34000

36000

38000

40000

42000

44000

46000

TELEMETERED SCE REGULATION DEPLOYED RESPONSIVE DEPLOYED BALANCING

Excess Load Imbalance SPINNING RESERVE TOTAL GENERATION

BPS & DYNAMIC OLC Obligation

ERCOT TOTAL24-Feb-03 06:00:00

ERCOT Totals Feb 24 06:00 to 08:00

-5000

-4000

-3000

-2000

-1000

0

1000

2000

3000

4000

5000

6000

6:00 6:05 6:10 6:15 6:20 6:25 6:30 6:35 6:40 6:45 6:50 6:55 7:00 7:05 7:10 7:15 7:20 7:25 7:30 7:35 7:40 7:45 7:50 7:55 8:00

35000

37000

39000

41000

43000

45000

47000

49000

TELEMETERED SCE REGULATION DEPLOYED RESPONSIVE DEPLOYED BALANCING

Excess Load Imbalance SPINNING RESERVE TOTAL GENERATION

BPS & DYNAMIC OLC Obligation

ERCOT TOTAL25-Feb-03 06:00:00

Feb 25 06:00 to 08:00

-4000

-3000

-2000

-1000

0

1000

2000

3000

4000

5000

8:00 8:05 8:10 8:15 8:20 8:25 8:30 8:35 8:40 8:45 8:50 8:55 9:00 9:05 9:10 9:15 9:20 9:25 9:30 9:35 9:40 9:45 9:50 9:55 10:00

35000

37000

39000

41000

43000

45000

47000

49000

TELEMETERED SCE REGULATION DEPLOYED RESPONSIVE DEPLOYED BALANCING

Excess Load Imbalance SPINNING RESERVE TOTAL GENERATION

BPS & DYNAMIC OLC Obligation

ERCOT TOTAL25-Feb-03 08:00:00

Feb 25 08:00 to 10:00

-4000

-3000

-2000

-1000

0

1000

2000

3000

4000

5000

6000

10:00 10:05 10:10 10:15 10:20 10:25 10:30 10:35 10:40 10:45 10:50 10:55 11:00 11:05 11:10 11:15 11:20 11:25 11:30 11:35 11:40 11:45 11:50 11:55 12:00

35000

37000

39000

41000

43000

45000

47000

49000

TELEMETERED SCE REGULATION DEPLOYED RESPONSIVE DEPLOYED BALANCING

Excess Load Imbalance SPINNING RESERVE TOTAL GENERATION

BPS & DYNAMIC OLC Obligation

ERCOT TOTAL25-Feb-03 10:00:00

Feb 25 10:00 to 12:00

-4000

-3000

-2000

-1000

0

1000

2000

3000

4000

5000

6000

12:00 12:05 12:10 12:15 12:20 12:25 12:30 12:35 12:40 12:45 12:50 12:55 13:00 13:05 13:10 13:15 13:20 13:25 13:30 13:35 13:40 13:45 13:50 13:55 14:00

30000

32000

34000

36000

38000

40000

42000

44000

46000

48000

50000

TELEMETERED SCE REGULATION DEPLOYED RESPONSIVE DEPLOYED BALANCING

Excess Load Imbalance SPINNING RESERVE TOTAL GENERATION

BPS & DYNAMIC OLC Obligation

ERCOT TOTAL25-Feb-03 12:00:00

Feb 25 12:00 to 14:00

-3000

-2000

-1000

0

1000

2000

3000

4000

5000

6000

7000

6:00 6:05 6:10 6:15 6:20 6:25 6:30 6:35 6:40 6:45 6:50 6:55 7:00 7:05 7:10 7:15 7:20 7:25 7:30 7:35 7:40 7:45 7:50 7:55 8:00

30000

32000

34000

36000

38000

40000

42000

44000

46000

48000

50000

TELEMETERED SCE REGULATION DEPLOYED RESPONSIVE DEPLOYED BALANCING

Excess Load Imbalance SPINNING RESERVE TOTAL GENERATION

BPS & DYNAMIC OLC Obligation

ERCOT TOTAL26-Feb-03 06:00:00 Feb 26 06:00 to 08:00

0

500

1000

1500

2000

2500

3000

3500

6:00 6:05 6:10 6:15 6:20 6:25 6:30 6:35 6:40 6:45 6:50 6:55 7:00 7:05 7:10 7:15 7:20 7:25 7:30 7:35 7:40 7:45 7:50 7:55 8:00

0.00%

1.00%

2.00%

3.00%

4.00%

5.00%

6.00%

7.00%

8.00%

9.00%

10.00%

Load Imbalance Load Imbalance %

24-Feb-03 06:00:00

Load Imbalance Feb 24 06:00 to 08:00

0

500

1000

1500

2000

2500

3000

3500

6:00 6:05 6:10 6:15 6:20 6:25 6:30 6:35 6:40 6:45 6:50 6:55 7:00 7:05 7:10 7:15 7:20 7:25 7:30 7:35 7:40 7:45 7:50 7:55 8:00

0.00%

1.00%

2.00%

3.00%

4.00%

5.00%

6.00%

7.00%

8.00%

9.00%

10.00%

Load Imbalance Load Imbalance %

25-Feb-03 06:00:00 Feb 25 06:00 to 08:00

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

8:00 8:05 8:10 8:15 8:20 8:25 8:30 8:35 8:40 8:45 8:50 8:55 9:00 9:05 9:10 9:15 9:20 9:25 9:30 9:35 9:40 9:45 9:50 9:55 10:00

0.00%

2.00%

4.00%

6.00%

8.00%

10.00%

12.00%

Load Imbalance Load Imbalance %

25-Feb-03 08:00:00

Feb 25 08:00 to 10:00

4000

4200

4400

4600

4800

5000

5200

10:00 10:05 10:10 10:15 10:20 10:25 10:30 10:35 10:40 10:45 10:50 10:55 11:00 11:05 11:10 11:15 11:20 11:25 11:30 11:35 11:40 11:45 11:50 11:55 12:00

9.00%

9.50%

10.00%

10.50%

11.00%

11.50%

12.00%

12.50%

Load Imbalance Load Imbalance %

25-Feb-03 10:00:00

Feb 25 10:00 to 12:00

4800

4850

4900

4950

5000

5050

5100

5150

5200

5250

12:00 12:05 12:10 12:15 12:20 12:25 12:30 12:35 12:40 12:45 12:50 12:55 13:00 13:05 13:10 13:15 13:20 13:25 13:30 13:35 13:40 13:45 13:50 13:55 14:00

11.60%

11.80%

12.00%

12.20%

12.40%

12.60%

12.80%

13.00%

Load Imbalance Load Imbalance %

25-Feb-03 12:00:00

Feb 25 12:00 to 14:00

-600

-400

-200

0

200

400

600

800

1000

6:00 6:05 6:10 6:15 6:20 6:25 6:30 6:35 6:40 6:45 6:50 6:55 7:00 7:05 7:10 7:15 7:20 7:25 7:30 7:35 7:40 7:45 7:50 7:55 8:00

-1.50%

-1.00%

-0.50%

0.00%

0.50%

1.00%

1.50%

2.00%

2.50%

Load Imbalance Load Imbalance %

26-Feb-03 06:00:00

Feb 26 06:00 to 08:00

59.80

59.82

59.84

59.86

59.88

59.90

59.92

59.94

59.96

59.98

60.00

60.02

60.04

60.06

60.08

60.10

6:00 6:05 6:10 6:15 6:20 6:25 6:30 6:35 6:40 6:45 6:50 6:55 7:00 7:05 7:10 7:15 7:20 7:25 7:30 7:35 7:40 7:45 7:50 7:55 8:00

-720

-600

-480

-360

-240

-120

0

120

240

360

480

600

720

840

960

1080

FREQUENCY GOVERNOR RESPONSE

ERCOT TOTAL24-Feb-03 06:00:00

Total Governor Response Feb 24 06:00 to 08:00

59.80

59.82

59.84

59.86

59.88

59.90

59.92

59.94

59.96

59.98

60.00

60.02

60.04

60.06

60.08

60.10

6:00 6:05 6:10 6:15 6:20 6:25 6:30 6:35 6:40 6:45 6:50 6:55 7:00 7:05 7:10 7:15 7:20 7:25 7:30 7:35 7:40 7:45 7:50 7:55 8:00

-720

-600

-480

-360

-240

-120

0

120

240

360

480

600

720

840

960

1080

FREQUENCY GOVERNOR RESPONSE

ERCOT TOTAL25-Feb-03 06:00:00

Feb 25 06:00 to 08:00

59.80

59.82

59.84

59.86

59.88

59.90

59.92

59.94

59.96

59.98

60.00

60.02

60.04

60.06

60.08

60.10

8:00

8:05

8:10

8:15

8:20

8:25

8:30

8:35

8:40

8:45

8:50

8:55

9:00

9:05

9:10

9:15

9:20

9:25

9:30

9:35

9:40

9:45

9:50

9:55

10:0

0

-720

-600

-480

-360

-240

-120

0

120

240

360

480

600

720

840

960

1080

FREQUENCY GOVERNOR RESPONSE

ERCOT TOTAL25-Feb-03 08:00:00

Feb 25 08:00 to 10:00

59.80

59.82

59.84

59.86

59.88

59.90

59.92

59.94

59.96

59.98

60.00

60.02

60.04

60.06

60.08

60.10

-720

-600

-480

-360

-240

-120

0

120

240

360

480

600

720

840

960

1080

FREQUENCY GOVERNOR RESPONSE

ERCOT TOTAL25-Feb-03 10:00:00

Feb 25 10:00 to 12:00

59.80

59.82

59.84

59.86

59.88

59.90

59.92

59.94

59.96

59.98

60.00

60.02

60.04

60.06

60.08

60.10

-720

-600

-480

-360

-240

-120

0

120

240

360

480

600

720

840

960

1080

FREQUENCY GOVERNOR RESPONSE

ERCOT TOTAL25-Feb-03 12:00:00

Feb 25 12:00 to 14:00

59.80

59.82

59.84

59.86

59.88

59.90

59.92

59.94

59.96

59.98

60.00

60.02

60.04

60.06

60.08

60.10

6:00 6:05 6:10 6:15 6:20 6:25 6:30 6:35 6:40 6:45 6:50 6:55 7:00 7:05 7:10 7:15 7:20 7:25 7:30 7:35 7:40 7:45 7:50 7:55 8:00

-720

-600

-480

-360

-240

-120

0

120

240

360

480

600

720

840

960

1080

FREQUENCY GOVERNOR RESPONSE

ERCOT TOTAL26-Feb-03 06:00:00

Feb 26 06:00 to 08:00