The island that priced its own power

Open a Central Maine Power bill this fall and the supply line lands somewhere near 13 cents a kilowatt-hour, before delivery charges stack on top. Add it up and the average Maine household is paying roughly 32 cents a kilowatt-hour all in, per the U.S. Energy Information Administration's mid-2026 figures. That number would have been unthinkable for the mainland five years ago. On Isle au Haut, seven miles off Stonington, it would have sounded familiar the whole time.

The island's co-op, the Isle au Haut Electric Power Company, has charged on the order of 32 cents a kilowatt-hour for years. What changed is not the island's price. It is everyone else's catching up. This is a story about what happens when an island that could not afford to waste a watt starts teaching the mainland its math.

A cable from the early 1980s

Isle au Haut's power arrives by an undersea cable roughly seven miles long, laid in the early 1980s and long past the life its makers promised. The co-op serves about 140 accounts, year-rounders and summer families, and it has run that cable the way a boat owner runs an old engine: carefully, and with one eye on the gauges. In March 2020 the island lost power for 31 hours when the cable failed, a preview the co-op took seriously.

The fix most islands choose is the obvious one: a new cable. Isle au Haut chose it too, and per the co-op's own site the replacement cable project is now complete. That is the news most ratepayers would stop at. The co-op did not stop there.

The microgrid that stayed on paper

Back in 2020, the plan was bolder. With a $211,000 grant from the U.S. Department of Agriculture, the co-op scoped a 311-kilowatt solar array at the island's ferry landing, paired with about one megawatt-hour of storage and a scheme to stash heat in water using heat-pump water heaters across member homes. The whole build was priced near $1.9 million. The idea was not energy independence as a slogan. It was a hedge: when the cable died, the island would keep its freezers, its lights, and its ferry terminal running.

By 2022 the co-op had quietly concluded the cable replacement was the more reliable near-term buy, and the microgrid went back into a drawer. Neighboring islands drew their own lessons. Monhegan, facing the same aging-cable arithmetic, chose efficient diesel microturbines rather than solar. The Cranberry Isles organized a community solar association. Swan's Island has explored its own designs. None of this is glamorous. All of it is the same question: what does a kilowatt-hour cost when the line that carries it has a birthday older than the ferry captain?

This year the drawer opened again. The co-op says it has applied for a U.S. Department of Energy grant to design a new automated microgrid, this time pairing solar with batteries, with the new cable in place as backup rather than lifeline. A design grant is not a build. It is, however, the first time the island's two answers, the cable and the microgrid, stop competing with each other.

What the island math says about yours

Here is the mainland part. Maine's average residential rate was roughly 28 cents a kilowatt-hour in mid-2025, per the EIA, and roughly 32 cents by mid-2026. The island premium that once looked extreme has narrowed to nearly nothing. That does not mean mainland bills are doomed to island levels forever; rates move with gas prices, contracts, and grid spending. It means the logic that long governed island power now governs everyone: a watt saved is cheaper than a watt generated, and a watt stored at 6 p.m. is worth more than one made at noon.

An island runs its grid the way a tight household runs a budget. The mainland is starting to live on the same budget, just with more zeros.

This is why the same hardware keeps surfacing in both places. Efficiency Maine's heat pump rebates continue in 2026, with a $500 bonus for qualifying whole-home upgrades, even as the federal 25C tax credit expired at the end of 2025. A five-state New England Heat Pump Accelerator launched in late 2025 to keep the installer pipeline full. None of these programs mentions Isle au Haut. Every one of them is the island's playbook, mainland edition.

Why the grid operator is watching

Isle au Haut's co-op sits outside ISO New England's footprint in the practical sense; the grid operator does not dispatch the island's diesels or read its meters. But the region's operator has the same winter problem at larger scale. New England's peak arrives after sunset on cold evenings, exactly when an island microgrid leans hardest on storage. The New England Clean Energy Connect, the 1,200-megawatt line from Hydro-Québec that entered service in January 2026, is the region-scale version of the island's new cable: imported firm power that does not care whether the sun is up. Massachusetts contracted for 9.55 terawatt-hours a year from the line, about a fifth of that state's annual demand.

The honest summary: cables, imports, and batteries each cover part of the winter evening, and nobody at any scale has solved all of it. The island just has less room to pretend otherwise.

Worth watching this week

• a.The Isle au Haut co-op's Department of Energy grant application; a design award would put real numbers on the solar-and-battery plan for the first time.
• b.Efficiency Maine's 2026 rebate schedule, including the $500 whole-home heat pump bonus; program pages carry the current figures, and they change.
• c.Any movement on power contract talks for the Gulf of Maine research array, on hold since spring 2025; the state's 3-gigawatt-by-2040 goal does not advance itself.
• d.ISO New England's winter reliability outlook, due ahead of the heating season; last year's lesson was that January, not July, sets the region's homework.
• e.Standard-offer supply rates from Central Maine Power and Versant at the next reset, the fastest-moving line on a mainland bill.