Grid Hardening: How Utilities Are Improving Reliability
Tracking the infrastructure investments that show up in U.S. Energy Information Administration EIA Form 861 reliability data, and what they mean for your power quality. According to the U.S. Energy Information Administration, 918 electric utilities serving more than 124,493,803 customers reported SAIDI and SAIFI reliability metrics through the 2023 Form 861 filing year (last refreshed June 2026), with the national nMED (no-major-event-day) SAIDI average holding near 145 minutes per customer per year, in line with 2020's 135-minute baseline. See our methodology for refresh cadence.
What Grid Hardening Means
Grid hardening refers to utility investments designed to make power infrastructure more resilient to weather, equipment failure, and demand stress. These investments are the primary lever utilities have to improve their SAIDI and SAIFI metrics over time. The EIA Form 861 data tracked on PlainUtility shows the aggregate results of these investments, or lack thereof, in the reliability trends for each utility.
Common grid hardening strategies include underground cable conversion, vegetation management programs, pole replacement, conductor upgrades, automated switching and sectionalizing, and distributed energy resource integration. Each addresses a different failure mode, and the most effective utilities typically invest across multiple strategies simultaneously.
Vegetation Management
Tree contact with power lines is the leading cause of weather-related outages in most service territories. Utilities with aggressive vegetation management programs, regular trimming cycles, hazard tree removal, and right-of-way clearing, consistently report lower nMED SAIDI values than peers with minimal programs. The effect is particularly visible in forested regions where tree density creates high exposure.
The challenge is economic: comprehensive vegetation management across thousands of miles of distribution line is expensive, and the benefits are spread across all customers. Cooperatives serving remote, forested territories face the steepest cost-per-customer for this investment. Check your utility's reliability trend on PlainUtility - an improving nMED trend often reflects vegetation management investment.
Underground Conversion
Converting overhead distribution to underground cables eliminates exposure to wind, ice, and tree contact, the three leading outage causes. Urban and suburban utilities that have made this investment typically report SAIDI values 50-70% lower than comparable overhead systems.
However, underground conversion costs 5-10x more per mile than overhead construction, and underground faults are harder to locate and slower to repair when they do occur. This makes underground conversion most cost-effective in dense urban areas where the investment is spread across more customers per mile. Compare utilities in your state to see how underground vs overhead infrastructure correlates with reliability outcomes.
Smart Grid and Automation
Advanced Distribution Management Systems (ADMS), automated reclosers, and smart sectionalizing switches can reduce outage duration by automatically isolating faulted sections and rerouting power to affected customers. These technologies do not prevent initial outages but can dramatically reduce restoration time, sometimes from hours to minutes.
The effect shows up most clearly in SAIDI trends for utilities that have deployed automation widely. If you see a utility's SAIDI improving while SAIFI stays roughly constant, automation may be the driver, outages still occur at similar frequency, but each outage lasts shorter because of automated switching.
What This Means for Consumers
Grid hardening investments eventually show up in EIA reliability data, but with a lag, capital projects take years to plan, fund, and execute. When evaluating your utility, look at the multi-year trend in nMED SAIDI rather than any single year. A steady improvement over 3-4 years is a strong signal that investment is happening and producing results.
Use our rankings to identify utilities that have shown the most improvement, and explore individual utility pages to see year-over-year trends.
Related Guides
Sources: U.S. Energy Information Administration, EIA Form 861.
Download the EIA Form 861 reliability extract cited on this page: eia-form-861-reliability-statistics.csv (CC BY 4.0).