Joel Koepke, P.E.ERCOTOperations Support Engineer

ERCOT Experiences During Summer 2011

2

Objectives

• Identify weather and nature challenges • Identify variables leading to EEAs• Identify mitigating actions of August 4th EEA• Identify outlook and changes for Summer

2012

3

Weather Extremes

4

High-Pressure System

5

Record Drought

6

West Texas fires in March through May

ERCOT Outages

Stations Impacted

Approximate cost of Transmission equipment damage and maintenance

Fire Contamination

$3,994,264 $1,340,940

Approximate cost of Distribution equipment damage and maintenance

Fire Contamination

$1,500,000 $313,780

Approximate Cost of Congestion

Day-Ahead Market Real-Time Market

$2,170,840.56 $1,127,056.03

Wildfires

7

Tested Situational Awareness Tools

8

Record Heat

9

Average Min/Max Load Values

June – August of 2009 - 2011

10

Instantaneous Summer Peak

Summer Energy Emergency Alerts

12

1

2A

2B

3

2011 EEA Procedure

August 2011Sunday Monday Tuesday Wednesday Thursday Friday Saturday

31 1 2

EEA 13

EEA 14

EEA 2B5

EEA 16

7 8 9 10 11 12 13

14 15 16 17 18 19 20

21 22 23

EEA 124

EEA 2A25 26 27

28 29 30 31 1 2 3

June 2011Sunday Monday Tuesday Wednesday Thursday Friday Saturday

26 27

EEA 128 3 4 5 6

2011 Summer Energy Emergency Alerts

14

PRC

• Physical Responsive Capability (PRC)– A representation of the total amount of system wide On-Line

capability that has a high probability of being able to quickly respond to system disturbances

15

June 27th EEA Highlights

• 3 unit trips in less than 2 hours– Total of 1,800 MW

• Large wind decline– Drop of 4,200 MW in 4 hours

• Large load increase– Increase of 4,000 MW in 2 hours

• Below 2,300 MW of Reserves for 1 minute• EEA lasted for 1 hour and 25 minutes

16

June 27th EEA - Frequency

17

June 27th EEA- Wind and Load

Unit Trips

18

June 27th EEA – Physical Responsive Capability

August 2011Sunday Monday Tuesday Wednesday Thursday Friday Saturday

31 1 2

EEA 13

EEA 14

EEA 2B5

EEA 16

7 8 9 10 11 12 13

14 15 16 17 18 19 20

21 22 23

EEA 124

EEA 2A25 26 27

28 29 30 31 1 2 3

20

August Peak Loads

8/3: Record Peak

21

Variables Affecting Physical Responsive Capability

– Online generation– System load magnitude– Resource outages and derates– Wind output– DC tie imports

22

Outaged Resource Capacity – 2011

23

Outaged Resource Capacity – August

24

Outaged Resource Capacity – Week View

Geographic Wind Regions

26

Average Summer Wind Contribution

27

Average EEA Wind Contribution

28

Summer vs. EEA Comparison – Total Wind

29

Summer vs. EEA Comparison – West Wind

30

Summer vs. EEA Comparison – South Wind

31

Summer vs. EEA Comparison – ERCOT Load

32

DC-Tie Imports: August 2nd – August 5th

-1,200

-1,000

-800

-600

-400

-200

0

200

400

MW

Total DC Tie Flow East DC Tie Net North DC Tie Net South DC Tie Net

August 2, 2011EEA Level 1

August 3, 2011EEA Level 1

August 4, 2011EEA Level 2B

August 5, 2011EEA Level 1

840 MW

763 MW

1,039 MW998 MW

Load Resources and EILS deployed

August 4th EEA Level 2B

34

1,392 MW Non-Spin deployed

August 04, 2011 - EEA Level 2B

Issued Watch

Reserves below 2,500 MW

1:25 PM

Cancelled Advisory

10:17 PM

Note: Watch also include:

•Qualified Scheduling Entity Hotline Call

•Transmission Operator Hotline Call

•Postings on the Market Information System and ERCOT website

Cancelled Watch

Issued OCNProjected reserve capacity shortage for hours 14:00 through 21:00

0:06 AM

12:38 PM

Issued Advisory

Reserves below

3,000 MW

2:32 PM 6:09 PM

Cancelled OCN

ERCOT ran out of regulation and issued manual Responsive Reserve deployment

2:15 PM

8:38 PM

3:44 PM

Load Resources Recalled

Move to EEA 2A

From EEA 2B

Move to EEA 1

From EEA 2A

5:53 PM 6:52 PM 8:49 PM

1:45 PM

EILS

Recalled

4:05 PM

EILS deployment Business Hours 3

AUGUST 4 WATCH FOR EXTREME HEAT STILL IN EFFECT

AUGUST 4 WATCH FOR EXTREME HEAT STILL IN EFFECT

35

ERCOT Load, Wind, and PRC8/4/2011 00:00–12:00

36

Outaged Capacity8/4/2011 00:00–12:00

37

ERCOT Load, Wind, and PRC8/4/2011 12:00–24:00

38

Outaged Capacity8/4/2011 12:00–24:00

39

1,039 MW

594 MW

229 MW

216 MW ERCOT had a max import of 1,039 MW across the DC Ties

East DC Tie= 594 MW

North DC Tie= 216 MW South DC Tie=229 MW

DC Tie Imports: 8/4/2011

40

ERCOT Load, Online Capacity, Offline Non-Spin and Net DC flow

59.8

59.9

60

60.1

30,000

35,000

40,000

45,000

50,000

55,000

60,000

65,000

70,000

75,000

HzMW

ERCOT Load

Online capacity

Online Capacity + Offline Non-Spin

Online Capacity + Offline Non-Spin + Net DC flow

Frequency

41

Summer 2012 Outlook

42

ERCOT CDR - Report on the Capacity, Demand, and Reserves in the ERCOT Region

• Long-term planning tool• Uses normalized assumptions

– Normal weather basis– Does not include Resource outages

• Summer Summary released in December of 2011.– Peak Demand – 66,195 MW

• 64,618 MW firm load

• 738 MW of firm load added since June CDR

– Available Capacity – 72,444 MW– Reserve Margin – 12.11%

43

Seasonal Assessment of Resource Adequacy (SARA)

• New report• Evaluates near-term Reserve adequacy

– Uses more recent seasonal climate forecast– Accounts for specific events (e.g. Drought)

• Evaluate the range of reserves usage in a deterministic manner– Uses of reserves:

• Higher peak demands due to above normal weather

• Forced generation outages

• Planned generation outages

• Atypical issues like drought

• Lower wind availability

• Determines the likelihood of Reserves dropping below the 2,300 MW threshold.

44

Emergency Interruptible Load Service (EILS)

• Proposed Changes– Allow Distributed Generation and unregistered generation to

participate• New capacity

– Remove the 1 MW minimum offer• Improve QSE flexibility

• Increase participation

– Explore the possibility of a 30-min product• Increase participation

Questions?