IOU · New Hampshire · EIA 24590
Unitil Energy Systems
IOU · New Hampshire · 64K customers. According to the U.S. Energy Information Administration's EIA Form 861, reliability for 2023 shows SAIDI 257 minutes/customer.
Reliability verdict
Unitil Energy Systems shows above-average chronic reliability in 2023: 91 minutes SAIDI excluding major events (257 minutes including them) across 64K customers.
- 257 min
- SAIDI 2023
- 1.55
- SAIFI 2023
- 91 min
- SAIDI ex-MED
- 64K
- Customers
Chronic reliability judged on SAIDI excluding major event days when reported (IEEE 1366). Source: EIA Form 861 · August 2026.
Signature read: mid-cohort SAIDI between the 96 and 258 minute tercile cuts.
What mid-pack Unitil Energy Systems filings show
Unitil Energy Systems is an investor-owned utility operating in New Hampshire under EIA identifier 24590. It reports service to approximately 64,256 customer accounts and generated about $0.18 billion in annual electric revenue, with a service footprint spanning 39 ZIP codes. Because it is investor-owned, the state public utility commission oversees its rate cases and reliability performance rather than a local board.
In 2023, the average Unitil Energy Systems customer experienced 256.6 minutes of power interruptions, the industry-standard SAIDI metric (System Average Interruption Duration Index). Excluding major weather events from that total, that keeps this utility below the typical 120–180 minute national benchmark, consistent with a well-hardened distribution system and fast restoration crews. The SAIFI figure, which tracks average outage events per customer, came in at 1.55 for the same period, meaning customers statistically saw about 2 distinct interruptions that year. Once major event days (hurricanes, ice storms) are excluded, SAIDI comes down to 90.9 minutes, and the spread against the headline 256.6 indicates how much weather, versus routine infrastructure, drove the outage total.
Unitil Energy Systems has 4 years of continuous EIA reporting on file (2020–2023), enough to read a real trend rather than a single-year snapshot. SAIDI has increased from 176.6 to 256.6 minutes, which may reflect either worsening weather exposure or delayed grid modernization.
Based on this utility's own EIA Form 861 reliability record -- baseline (major-event- excluded) outage duration, total outage duration, and outage frequency -- each benchmarked against every reporting utility nationwide. Not a measure of electricity rates or customer service, which this portal does not track.
257 minutes per customer per year
Power-out minutes per year (2023)
SAIDI by year (2020-2023)
Minutes per customer-year · EIA Form 861
Year-by-year SAIDI for Unitil Energy Systems from the same EIA filings as the table below. Lower is better; major-event years can spike the headline figure.
Unitil Energy Systems SAIDI trend
Unitil Energy Systems vs the nationwide SAIDI distribution
Where this utility's headline SAIDI sits among every EIA Form 861 utility with a reported figure
257 Around the middle fewer outage minutes than 34% of 911 utilities
Utilities nationwide, banded by latest reported SAIDI (minutes)
Each bar is a band; taller bars hold more utilities. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.
Source U.S. EIA Form 861 reliability filings · August 2026
Price vs. reliability
Where Unitil Energy Systems sits on price vs. reliability
Among the 781 U.S. utilities large enough to report both revenue per customer and a recent outage record, Unitil Energy Systems charges more per customer than 64% of them, and is more reliable (lower SAIDI) than 37% of them, placing it in the quadrant where it pays more but is LESS reliable, a premium price without a reliability payoff. Revenue per customer and outage minutes are independent figures: paying more does not guarantee fewer outages.
Revenue per customer: $2,787/year · Latest SAIDI: 256.6 minutes/year.
SAIDI 2023 breakdown: 256.6 minutes
Reliability Trend (2020–2023)
| Year | SAIDI (min) | SAIDI nMED | SAIFI | Customers |
|---|---|---|---|---|
| 2020 | 176.6 | 120.0 | 1.859 | 78,697 |
| 2021 | 140.9 | 102.8 | 1.326 | 78,935 |
| 2022 | 275.6 | 70.8 | 1.400 | 79,123 |
| 2023 | 256.6 | 90.9 | 1.547 | 79,306 |
SAIDI nMED = SAIDI without major event days. Source: EIA Form 861.
Service Area
Unitil Energy Systems serves 39 ZIP codes in New Hampshire.
Frequently Asked Questions
How reliable is Unitil Energy Systems?
Unitil Energy Systems had a SAIDI of 256.6 minutes in 2023 including major weather events, but 90.9 minutes excluding them (the industry-standard measure of routine reliability, so the gap traces back to a major storm that year, not a chronic issue). Excluding major storm impacts, this beats the national average, a sign of above-average reliability.
What type of utility is Unitil Energy Systems?
Unitil Energy Systems is classified as a IOU serving New Hampshire.
How many customers does Unitil Energy Systems serve?
Unitil Energy Systems serves approximately 64,256 customers in New Hampshire.
How has Unitil Energy Systems's reliability changed over time?
Unitil Energy Systems has 4 years of reliability data (2020-2023). This utility's SAIDI has stayed fairly flat over the period. Review the trend table above for year-by-year detail.
Utility Profile
- Type
- IOU
- State
- New Hampshire
- Customers
- 64,256
- Annual Revenue
- $0.18B
- EIA ID
- 24590
Explore
Utilities with similar EIA profiles
Two cross-state peer sets for Unitil Energy Systems. Same-state SAIDI neighbors stay in Read-with below; these neighborhoods are nearest other-state utilities with at least 10,000 reported customers.
Similar customer count
Nearest utilities by Form 861 customers (64K here), outside New Hampshire.
Similar chronic SAIDI
Nearest utilities by latest SAIDI minutes (256.6 here), outside New Hampshire, excluding the customer-peer set.
Source: U.S. Energy Information Administration Form 861 annual electric power industry survey · ZIP service territory: OpenEI. Disclaimer: informational only, not professional advice. See full disclaimer · methodology.