Grid reliability · 2024 · 13 reporting utilities

Power outages in Massachusetts

The utilities that reported here serve 3,043,016 customers between them, not the whole state. Weighted by customer count, they averaged 77 min without power in an ordinary year and 104 min once major events are counted. Each figure comes only from the filers that published it, and the counts are below.

What it means

Why there are two numbers

Across the utilities that filed both figures, major events account for 26% of the outage time Massachusetts recorded once they are counted: 105 min against 77 min without them, a factor of 1.4×. Solar panels alone do not help during an outage, because a grid-tied array shuts down when the grid does, so riding through one is a battery question. This figure will not answer it: it is an annual average across a utility’s customers, not the length or the load of any single outage. What it does say is how much of the outage time here arrives with major events rather than on ordinary days.

The comparison is drawn from the 12 utilities that filed both figures of the 13 reporting here, so both sides of the ratio describe the same set of customers. The two headline figures above are averaged over everyone who filed each one, so dividing them would not give this number.

Ordinary year77 min40 of 51 jurisdictions, longest first · 12 filings

With major events104 minStorms, ice, and fires included as filed · 13 filings

Interruptions a year0.7×Ordinary year; 0.9× with major events

The bill sideWhat solar offsetsRates and modelled output by utility

The utilities behind the average

Each of Massachusetts’s figures is a customer-weighted average of the filings that carried that metric, not of the table as a whole: the ordinary-year average is built from 12 filings and the storm-inclusive average from 13 filings, out of 13 filings that published an outage figure at all. Those two sets are not the same utilities, so the two columns cannot be compared filer by filer. A utility that filed without publishing a metric, or whose two major-event variants contradicted each other, is absent from that metric rather than counted as zero.

Reported interruption metrics for 2024, largest utility first.
Utility	Customers	Ordinary year	With major events	Interruptions
NSTAR Electric Company	1,462,127	66 min	81 min	0.6×
Massachusetts Electric Co	1,345,044	91 min	2.2 hr	0.8×
City of Taunton	39,242	3.2 hr	3.2 hr	2.4×
Town of Reading - (MA)	32,638	23 min	46 min	0.3×
Fitchburg Gas & Elec Light Co	30,873	65 min	65 min	1.0×
City of Chicopee - (MA)	26,049	not reported	11 min	not reported
City of Westfield - (MA)	18,194	46 min	2.0 hr	1.0×
City of Holyoke - (MA)	17,557	62 min	62 min	1.3×
Town of Braintree - (MA)	16,598	3 min	3 min	0.0×
City of Norwood - (MA)	16,301	25 min	64 min	0.5×
Nantucket Electric Co	13,995	50 min	2.3 hr	0.3×
Town of North Attleborough - (MA)	13,894	6 min	6 min	0.1×
Town of Mansfield - (MA)	10,504	10 min	16 min	0.1×

What this page is not

It is a state average of utility filings, not a measurement at any address. Each filing is itself an average over a whole service territory, so a rural feeder and a downtown network arrive here as one number, and nothing in this dataset says how far an individual address sits from it. Nothing here predicts a future year either, and a single severe storm can move a utility’s figure by an order of magnitude.

The methodology page states the sources, the definitions, and the limits. Back to the Grid Reliability Index

Source: U.S. Energy Information Administration, Form EIA-861 reliability file, data year 2024, covering 2024-01-01 through 2024-12-31. The snapshot covers no later period.