An Island Keeps Its Lights On

By Eva Murray

Matinicus Island, roughly 20 miles south-southeast of Rockland, has a population number that is hard to pin down. “How many people live on the island?” is a common question, but answering with a tongue-in-cheek, “Oh, 100, I guess — plus or minus 75,” is pretty accurate. On some mid-winter nights, an islander can count the neighbors on fingers and toes.

Matinicus Island. Photos by E. Murray.

Matinicus is a lobstering community, and as such, depends upon one industry. Unlike many other mid-coast towns, tourism is not a substantial part of the island’s economy. The municipality officially called Matinicus Isle Plantation is doing its best to remain viable.

This year, two children are attending the one-room, kindergarten through 8th-grade school, after a couple of years with none enrolled. The island’s small library, only a few years old, offers free public wireless access, something available nowhere else on the island where cell signal is erratic and unreliable. A new state ferry vessel began service to Matinicus in September of 2024. At 104 feet — small for a vehicle ferry — the Charles Norman Shay is the only vessel in the state’s fleet that can physically fit in Matinicus Harbor. And Penobscot Island Air, the bush-pilot-style air taxi service that carries passengers, packages and groceries to the island, remains a steady and reliable presence under new owner Sean Creeley.

An array of solar panels and battery storage system compliment the new Tier 4 diesel generator to provide Matinicus residents' electricity needs. E. Murray photo.

The big news, however, is the island’s power company.

Matinicus Island has never been served by a cable from a mainland power company. The distance spanned would be much too large, and regular underwater cable maintenance would be effectively impossible. Until the mid-1960’s, any islander who wanted to watch television fired up their own household generator. The earliest iterations of Matinicus Light and Power — later named the Matinicus Plantation Electric Company — were very basic, with second-hand diesel engines, little efficiency, and no real engineering design.

The station was upgraded in 1983 to include a professionally designed system incorporating three Detroit 3-71 diesel gensets (to be replaced in time with 4-71s) and a bank of electronic switchgear to add or shut down engines as needed for variations in power demand through the day and over the year.

The municipally-owned electric utility ran for decades under the watchful eyes of Charlie Pratt, Paul Murray, and Gary Peabody. However, 40+ years of wear and tear, a shortage of decent replacement parts, and simple old age eventually made repairs extremely difficult. Power company station operators were scrounging for parts on eBay. Billings Diesel in Stonington, which did the deep maintenance of the engines for the power company, recently had no supply of high-quality replacement parts for the old 71-series diesels. The switchgear was actively failing, making automated communication between engines a thing of the past. Some components in the switchgear had come from companies that no longer existed.

Matinicus needed new equipment.

Newer versions of the 1980’s-era engines and technology were not to be had. EPA regulations for new diesel engines changed how they could be used to generate power. Simply replacing the engines wasn’t an option.

In 2024, a complete redesign was proposed by islander Phil Davies, who worked with the island’s local government to figure out a thousand details. Davies, who served as an occasional substitute station operator, created computer simulations to study what might be possible. Davies’ job evolved, and he became the organizer of the whole effort, spending as much time clearing woods and doing site prep as crunching numbers.

Funding came from multiple public and private sources and pro bono services. “We did get a $50,000 state grant that reimbursed us for the design cost. We also received a $10,000 grant from the Island Institute,” said Dorian Edwin, Matinicus municipal treasurer. A USDA matching grant was secured to help offset some costs of solar panels and energy storage, however, most of the funding will ultimately come from Matinicus property taxpayers and ratepayers.

On July 4, 2025, during the busiest weekend in recent memory, the island’s power grid was shifted over to the new generating station. A few weeks later, a 160-kW solar array was up and running, taking on a substantial portion of the power demand.

The single Tier 4 Perkins diesel powering a 150-kW generator now typically runs for only a couple of hours a day. “That’s pretty amazing,” says Davies. “I mean, that’s the headline, right there.” The photovoltaic component (a 2/3- acre solar array) and hybrid supercapacitor/battery storage system changes everything about how the island power company lights the roughly 130 island homes and workplaces.

Matinicus still maintains some very old equipment such as transformers and the overhead wire itself, both of which eventually will need replacement.

The small size of an island grid gives electrical engineers fits. There is a lot that is peculiar about a system so tiny (generating under 100 kW most of the time, and sometimes way under). For example, one household or workshop starting up a high-demand electrical appliance can change the balance of the whole microgrid. The old Matinicus power plant could better absorb that sort of imprecision.

“The old Detroit engines could run at any load,” Davies observed. “If they want to run at 10 kilowatts and trudge along at 10 percent of their operating capacity, they could do that. The new Tier 4 diesels that are very clean in terms of emissions — and we had to buy a Tier 4 — cannot do that.”

The new system, controlled by purpose-built microgrid software, is much more sensitive to irregularity and system imbalance, and has to be taught to forgive a few anomalies caused by small size and some worn-out infrastructure. “Working in the powerhouse” is now more about adjustments made on a laptop, rather than with the turn of a wrench, which is not what islanders are used to. But so far, so good. The station is much quieter, the island uses considerably less diesel fuel, and what really matters is: the lights are on.