COM/CXW/k47/eap Mailed 3/7/2002

Decision 02-03-024 March 6, 2002

BEFORE THE PUBLIC UTILITIES COMMISSION OF THE STATE OF CALIFORNIA

Order Instituting Rulemaking into the operation of interruptible load programs offered by Pacific Gas & Electric Company, San Diego Gas & Electric Company, and Southern California Edison Company and the effect of these programs on energy prices, other demand responsiveness programs, and the reliability of the electric system.

Rulemaking 00-10-002

(Filed October 5, 2000)

Phase 2

Voltage Reduction

(See Appendix A for List of Appearances)

TABLE OF CONTENTS

Title Page

INTERIM OPINION ON EMERGENCY VOLTAGE REDUCTION MEASURES 2 2

1. Summary 2 2

2. Background 2 2

3. Voltage Reduction Experience and Potential 4 4

4. Proposals 8 8

5. Discussion 9 9

5.1. Ongoing Voltage Reduction Measures 9 9

5.2. Emergency Measures 10 10

5.2.1. Need Has Subsided 11 11

5.2.2. Benefits Are Limited 11 11

5.2.3. Risks are Not Quantified but Potentially Great 12 12

5.2.3.1. Rule 2 and ANSI C84.1 15 15

5.2.3.2. Test Results 19 19

5.2.3.3. Stable Voltage 22 22

5.2.3.4. Liability 23 23

5.2.3.5. Risk of Voltage Reduction Compared to Rotating Outage 25 25

5.2.4. Other Reasonable Alternatives Are Preferable 26 26

5.2.5. Decline Other Variations of Emergency Voltage Reduction 27 27

5.2.6. Conclusion 29 29

6. Comments on Proposed Decision 30 30

Findings of Fact 30 30

Conclusions of Law 33 33

INTERIM ORDER 35 35

INTERIM OPINION ON EMERGENCY
VOLTAGE REDUCTION MEASURES

1. Summary

Several methods are used to balance electricity supply and demand to avoid outages. For example, supply may be increased by the addition of new power plants, or the use of existing backup generation. Demand may be decreased by the use of energy efficiency programs, conservation, or curtailment of service to interruptible customers. A reduction in system voltage may also decrease demand. As a last resort, rotating outages may be necessary.

We here consider the use of voltage reduction by electric utilities during peak demand periods as one of several tools to decrease the frequency or duration of rotating outages. As a result of our review, we endorse existing and ongoing voltage reduction efforts within current standards and rules. We encourage additional cost-effective voltage reduction measures, to be implemented during normal distribution substation work. We decline to order voltage reduction during system emergencies, however, given that the need for this tool has substantially moderated, the benefits are relatively small compared to associated risks, and other reasonable options are available. Parties may propose specific emergency voltage reduction measures for further consideration if the need resurfaces.