ERCOT Emergency Load Response Sam Jones Paul Wattles Steve Krein PUC Demand Response Workshop Sept. 15, 2006

ERCOT Emergency Load Response

Sam Jones Paul WattlesSteve Krein

PUC Demand Response Workshop

Sept. 15, 2006

2PUCT Workshop9/15/2006 2

Load Response at ERCOT

• Background– Under normal circumstances, adequate resources are on line or

available to deal with most situations (RRS, NSRS, RPRS) – Historical need for additional resources due to abnormal events

(usually weather related)• Cold weather events can lead to abnormally high load combined

with fuel curtailments (Feb. 2003)

• Shoulder month events caused by unusual weather at unexpected times (100º weather in April with 20% of capacity offline for seasonal maintenance)

– When abnormal events occur, additional ERCOT tools could reduce the possibility of a need for firm load shedding

– Shrinking reserve margins place the system at greater risk


0%

5%

10%

15%

20%

25%

30%

35%

40%

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

2010

2011

12.5%

Reserve Margins 1999-2011

Percentage difference between peak load forecast and available generation/resources

12.5% is the target minimum reserve margin established by ERCOT stakeholders and Board

*1,100 MW of mothballed units have been returned to service

Over 26,000 MW of new generation added after passage of Senate Bill 7

Since 1999:• 2,800 MW retired • 8,700 MW mothballed*

Future generation is officially counted only if interconnection agreement completed

Announced generation without interconnection agreements (excludes wind)

2008 is a major concern


Peak Load Variability (Highly Weather Sensitive)

• Swing of ~3500 MW in Peak Load from an “Average” Year to high and low• Represents about 5% of current Peak Capacity

• Load forecasts used for reserve margin calculations are based on average temperatures

Normalized Peak Load Duration

45000

47500

50000

52500

55000

57500

60000

0 5 10 15 20 25 30 35 40 45 50

Hours at Load Level

Lo

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(M

W)

1998

1999

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2003

2004

Average

ERCOT Peak Load Duration Data Normalized for Economic & Population Growth, 1998-2004


Increasing Demand for Power

• Region-wide demand is growing at an average of 2.3% per year

• Per-home energy consumption has doubled since 1980, despite appliance efficiency gains– Many more

devices in use • 60% of new homes

have ceilings of 9 ft. or higher

• 100% of new homes in southern U.S. have A/C So, what happens when all else fails?


ERCOT Emergency Operations

Operating Procedures scheduled for Board approval on 9/19/06

Event/Action Trigger

Operating Condition Notice Physical responsive reserve below 3300 MW

ADVISORY Physical responsive below 3000 MW

ALERT: Start RMR units, suspend unit testing, deploy RPRS & NSRS

Physical responsive below 2500 MW

Emergency Electric Curtailment Plan

Step 1: Dispatch all generation, public media appeal, DC Ties


Step 2: Deploy LaaRs Physical responsive below 1750 MW

Step 3: Instruct transmission operators to shed firm load

Frequency below 59.8 hz


April 17, 2006: 4-5 p.m.

• Additional load resources deployed shortly after 1600 could have averted the need for firm load shedding

0

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16:00:00 16:05:00 16:10:00 16:15:00 16:20:00 16:25:00 16:30:00 16:35:00 16:40:00 16:45:00 16:50:00 16:55:00 17:00:00

59.76

59.78

59.80

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59.96

59.98

60.00

60.02

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60.06

REGULATION RESPONSIVE NSRS DEPLOYED FREQUENCY

4 Unit Trips

Graph represents post-LaaR deployment

(instruction issued 15:34)

Firm Load Shed (instruction issued 16:13)


ERCOT Emergency Operations

A proposed new tool for the ERCOT toolbox

Event/Action Trigger

Operating Condition Notice Physical responsive reserve below 3300 MW

ADVISORY Physical responsive below 3000 MW

ALERT: Start RMR units, suspend unit testing, deploy RPRS & NSRS


Emergency Electric Curtailment Plan

Step 1: Dispatch all generation, public media appeal, DC Ties


Step 2: Deploy LaaRs Physical responsive below 1750 MW

Step 3: Instruct transmission owners to shed firm load

Frequency below 59.8 hz

New Step: Deploy EMERGENCY INTERRUPTIBLE LOAD


Emergency Interruptible Load Response at ERCOT

• Proposal for an Emergency Interruptible Load Response Program – Loads would respond:

• After all regular emergency resources (NSRS and RRS) have been deployed• Under low frequency conditions• Prior to shedding firm load

– Quantity would be based on averting historical firm load shedding events which have occurred in winter peak or shoulder months

• 1000 MW based on history

– Quantity could be adjusted based on projected reserve margins for the following year

– Expected deployment of these load resources would be infrequent • 1 or 2 events in 10 years

– An “event” could entail deployment over several consecutive days (due to an extreme heat wave for example)

– Customers making up these load resources should be prepared for interruption and would replace firm customers who are not prepared



• Advantages of an Emergency Interruptible Load Program:– Backstop in times of tight supply– Shedding voluntary and prepared end use customer load is

preferred over involuntary unprepared firm load shedding– Shedding load is 100% effective for balancing to available

generation– Societal cost should be lower than the cost of shedding firm load– Capital cost should be much lower than adding peak generation

capacity



• Potential Program Characteristics– Procurement/Payment

• Loads, through their QSEs, would competitively bid to provide service (similar to Black Start)

• 2-year contract term• Initial start-up payment at time of contract award• Pay for performance based on actual load response• End of contract term payment based on availability• Consider a price cap for total compensation



• Potential Program Characteristics – Dispatching and Operations

• Dispatched By ERCOT thru QSEs• Would be deployed as a single block after all existing

generation resources: under low frequency conditions but before any firm load shedding

• Needs to be quick responding (10 minute or less response time)

• Require IDR metering for measurement and verification – But no telemetry

• Limit number of hours to be curtailed in any given year



•Potential Program Participants–Large Commercial and Industrial Accounts –Government and Municipal Facilities–Retail Chains–Others???

Program should be open to QSEs serving both competitive and NOIE load



• A potential issue relating to customer performance:– Prospective customers may already participate in bilateral price

responsive load programs and/or 4CP load adjustments• Payment for emergency interruption thus should be based on

performance, tracked through IDR meter data

Transmission Connected Loads

3000

3200

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4000

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5000

12:00 13:00 14:00 15:00 16:00 17:00 18:00

Time

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(M

W)

June 1, 2006 June 13, 2006 (4CP)

Gap of 600MW on a probable 4CP day


Summary

Proposed Emergency Interruptible Load Program• ERCOT takes advocacy positions on policy issues when grid

reliability is affected– Proposed emergency interruptible load is a reliability tool

• Emergency interruptible load is needed ASAP– Region will be near or below minimum reserve levels in 2007 and

2008 (and possibly beyond), depending on weather extremes– ERCOT strongly recommends enabling by Spring ’07 shoulder

months• PUC action is crucial

– Stakeholders cannot be expected to develop a program in time, based on history of demand-side initiatives

• Fast-track authorization or commendation from commissioners will be necessary


Questions?

Documents

ERCOT Emergency Load Response Sam Jones Paul Wattles Steve Krein PUC Demand Response Workshop Sept. 15, 2006