The History of Load

Participation in ERCOT

DOE Workshop—Washington, DC

Mark Patterson

ERCOT Manager of Demand Integration

October 25, 2011

In the Beginning….

2002

– Texas Energy Markets are opened to competition

– Legacy interruptible programs are eliminated

– Large Industrial customers want to participate in Ancillary Service

Markets

– Market Rules (Protocols) changed to add new type of resource called

Loads acting as a Resource (LaaR)

– Instantaneous Interruptible customers transition to Responsive Reserve

Service (RRS)

– 10 minute and 30 minute customers initially consider providing Non-

Spinning Reserve Service but quickly transition to RRS

– Limits placed on maximum participation (25% of RRS capacity)

– Loads must meet similar requirements as generators

• Real Time Telemetry

• Dispatchable via a verbal dispatch instruction

• UFR for Frequency Response

2

10/25/2011

2002 to 2004

• Deployments are done for System Capacity Insufficiency and

Management of Zonal and Local Congestion

• Loads must have a relatively flat load profile in order to provide RRS

(batch process loads are not allowed to provide service)

• Loads must pass a qualification test to provide service

• 25% limit is raised to 33%

• Protocols are changed to create a new type of Resource called a

CLR but system changes are extensive and not implemented

• Numerous deployments for Zonal and Local Congestion

3 10/25/2011

2005 – 2006

• Protocols are changed to remove zonal deployments

• 33% limit is changed to 50%

• Firm Load Shed in April 2006 and first system wide deployment of

LaaRs

• Some Performance Issues Identified

– 20 minute initial response times

– Real time telemetry issues

– Qualification tests allow simulated testing

4 10/25/2011

• Protocol changes implemented to correct issues

– Simulated testing no longer acceptable – qualification tests

must include an actual deployment

– Tightened telemetry standards

– Provisions added to suspend LaaRs that fail to perform

• Response times go from 20 minute timeframe to 7-8 minutes

• Tests run to demonstrate viability of CLR

• Zonal market ends in December 2010

2007 – 2010

10/25/2011

5

2011

• Nodal Market Implementation

– Deployments now include XML message prior to the verbal

dispatch instruction

– Split deployment stack created

– Full implementation of CLR

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sLoad Resources Registered and Qualified for

ERCOT AS Market

Impact of Load Resources on AS Markets

10/25/2011

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ERCOT Load Resources Participating in Responsive Reserve Market

Summary

2006 2007 2008 2009 2010 2011***

Number of Participants 130 130 143 160 181 189

Registered Load (MW) 1966 2069 2153 2063 2382 2391

Load Resource RRS Awards ($ millions) * 48.4 53.2 115.8 41.6 54.1 108.3

Estimate for Total Load Resource Contribution

($ millions) ** 130.0 125.7 267.9 95.5 89.5 182.9

Weighted Average Price for RRS ($) 12.93 12.61 28.68 10.17 9.03 25.27

* Represents only portion that was awarded through ERCOT AS Market Auction

** Estimate for Total Load Resource Contribution uses the weighted average price for RRS as a proxy price for self provided Load Resources

*** Results thru 9/30/2011

Load Resource Response on 2/2/2011

10/25/2011

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ERCOT Load Resource RRS Deployment 2/2/2011

Load Resources Deployed (MW) Frequency

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Load Resource Response on 8/4/2011

10/25/2011

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ERCOT Load Resource RRS Deployment 8/4/2011

Load Resources Deployed (MW) Frequency

Emergency Interruptible Load Service (EILS)

11 10/25/2011

• Service provided by end use customers willing to interrupt during an

electric grid emergency

• An additional tool for ERCOT Operations, deployed ONLY in the late

stages of a grid emergency

• Requirements:

– Can be individual loads or aggregations

– 15-minute interval metering or statistically valid sample approved by

ERCOT

– Capability of interrupting at least 1 MW of load on 10 minutes notice at

any time during the committed hours

– No telemetry required, and not modeled in the Network Operations

Model

– 3 Contract Periods per year, each has 4 time periods

– Performance based on both availability and deployment metrics

– Dispatching and financial performance is between ERCOT and a QSE

12 10/25/2011

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MW

EILS Load Reduction 08/04/2011

Actual MW Baseline MW Obligation Load Reduction

Questions?

ON

OFF

10/25/2011

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