Customer-Focused Reliability Metrics: A Complement to System-Average Reporting
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Executive Summary
Many electric utilities have made measurable progress on reliability in recent years, yet system-average metrics that underpin most regulatory reporting (SAIFI, SAIDI, and CAIDI) do not, on their own, reveal whether that progress is reaching every customer. Localized areas of persistently poor reliability can remain obscured by improving averages, leaving some customers to experience repeated or extended outages. Two complementary customer-focused metrics defined in IEEE Standard 1366, Customers Experiencing Multiple Interruptions (CEMI) and Customers Experiencing Long Interruption Duration (CELID), directly address this gap by measuring the share of customers whose service falls below a defined threshold. Approximately fifteen U.S. jurisdictions and British Columbia have adopted requirements through rules, guidelines, or proceedings to report one or more customer-focused reliability metrics and adoption is expanding. In this paper, Forrest Small examines how utilities and regulators can adopt and apply these metrics to better align infrastructure investments with customer outcomes.
Key Questions
This paper answers the following questions:
- What do customer-focused reliability metrics measure, and what can they reveal?
- How can CEMI and CELID complement SAIFI and SAIDI?
- What role can customer-focused reliability metrics play in measuring resilience?
- Where are customer-focused reliability metrics being reported?
- How can utilities practically implement CEMI and CELID?
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All views expressed by the authors are solely the authors’ current views and do not reflect the views of Concentric Energy Advisors, Inc., its affiliates, subsidiaries, related companies, or clients. The authors’ views are based upon information the authors consider reliable at the time of publication. However, neither Concentric Energy Advisors, Inc., nor its affiliates, subsidiaries, and related companies warrant the information’s completeness or accuracy, and it should not be relied upon as such.