SAIDI and SAIFI have long been the standard metrics utilities use to measure and report electric reliability. Regulators track them. Boards set targets around them. Operational teams are evaluated by them. But as grid complexity grows and customer expectations evolve, a critical question is emerging: are we using these metrics to drive real improvement, or just to meet reporting thresholds?
At their core, SAIDI (System Average Interruption Duration Index) and SAIFI (System Average Interruption Frequency Index) were designed to measure the reliability of electric service from a system-wide perspective. SAIDI reflects the average total duration of interruptions for each customer served, while SAIFI measures how often the average customer experiences an interruption.
But while these averages are useful for benchmarking and regulatory comparisons, they often fail to reflect the lived experience of customers, the operational nuances faced by field teams, or the systemic constraints shaping outage patterns.
The Metrics Don’t Tell the Whole Story
Many utilities today find themselves in a paradox. Their SAIDI and SAIFI scores may fall within accepted thresholds, yet customer complaints about reliability persist. How can this be?
The answer lies in what these metrics hide:
- CEMI (Customers Experiencing Multiple Interruptions): Chronic outage pockets get buried in system-wide averages.
- Geographic variability: A region with extremely high interruption rates can be offset by another with very few, masking reliability problems.
- Time-of-day and critical use cases: A two-hour outage at 3 a.m. is not the same as one at 5 p.m. during peak load in extreme weather.
Metrics without context can become misleading. A utility may technically be “performing,” yet vulnerable communities, essential service zones, or high-DER penetration areas are still experiencing unacceptable reliability levels.
Why SAIDI and SAIFI Are Hard to Improve
Improving SAIDI and SAIFI on paper sounds straightforward: reduce the number and duration of outages. But in practice, several operational and structural challenges make it difficult:
- Delayed fault isolation and switching: Aging infrastructure and manual operations slow down restoration.
- Storm response inefficiencies: Without pre-staged materials and integrated crew tracking, restoration drags.
- QA/QC gaps during commissioning: Improperly tested assets can fail early, introducing new outage risks.
- Backlogs in vegetation management and inspections: Asset conditions directly influence outage frequency and duration.
- Inadequate outage analytics: Without high-resolution data, it’s difficult to pinpoint root causes or repeat patterns.
Making the Metrics Useful Again
To make SAIDI and SAIFI actionable, utilities need to shift from simply tracking these numbers to interrogating them:
- Break down events by geography, customer type, and voltage class.
- Overlay with CEMI-5 or CEMI-8 data to identify chronic outage clusters.
- Combine outage data with vegetation encroachment, asset age, and inspection history.
- Evaluate outage impact not just by duration, but by economic and social consequences.
When utilities treat reliability metrics as diagnostic signals—not just compliance benchmarks—they uncover opportunities that go beyond reactive maintenance.
Field-Driven Strategies That Move the Needle
Improving SAIDI and SAIFI isn’t solely about asset investment. It’s about execution. Here are field-proven strategies that have made a measurable difference:
- Proactive QA/QC: Commissioning that goes beyond checklists to validate functional system integrity can reduce early-life failures.
- Cross-phase material visibility: In multi-phase projects, misaligned or missing material is a common delay driver. Real-time material tracking prevents late-stage workarounds that introduce future risk.
- Pre-staged storm response plans: Assigning pre-identified switchable loads, clear restoration tiers, and accessible permits accelerates recovery.
- Detailed outage cause coding: Training field techs to accurately log outage origins creates better data for targeting improvements.
- Integrated planning cycles: Reliability teams, vegetation management, and capital planners need to share the same GIS-based outage intelligence.
None of these solutions are flashy. But they work.
Rethinking Planning Objectives
What if, instead of setting a goal of 0.9 SAIFI, utilities asked: Which customers are at risk of repeated outages this year, and how are we intervening? That shift—from score to impact—reframes the entire planning process.
Today’s reliability planning must account for more than system performance. It must also incorporate:
- Equity considerations: Are rural and underserved communities disproportionately impacted?
- DER sensitivity: Are outage-prone feeders limiting customer adoption of rooftop solar or EV charging?
- Climate vulnerability: Are high-SADI regions also facing heat or wildfire risk?
This is where traditional metrics can evolve into strategic tools.
SAIDI and SAIFI Are the Floor, Not the Ceiling
Metrics are only as valuable as the questions they prompt. SAIDI and SAIFI are a starting point—a way to anchor discussions about reliability, investment, and operational readiness. But to truly improve performance, utilities must dig deeper.
That means investing in outage analytics, aligning field execution with planning assumptions, and designing programs that improve customer outcomes, not just averages.
Because for the customer who lost power five times this quarter, the system-wide SAIFI number doesn’t matter. What matters is whether the utility knew—and did something about it.
For utilities trying to turn those signals into action, closing the gap between data, planning, and field execution is critical. At Think Power Solutions, we work with T&D teams to make reliability metrics more meaningful—helping identify outage patterns, optimize field workflows, and ensure operational feedback loops reach the people who can act on them. If you’re grappling with how to translate SAIDI and SAIFI into outcomes that matter, let’s talk.
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