Backup Power in
Whole-home RoseWater systems, Savant Power and standby generators for houses in town, Sconset, Madaket, Polpis and across the island.
Build Your Power PlanNearly all of Nantucket's power arrives through two cables under Nantucket Sound. When a storm brings down poles on the island, or one of those cables fails, help has to come by boat, and in the worst weather the boats do not run.
The island's population rises about fivefold in summer, so the grid has to carry a much bigger load for part of the year, and a house closed for the winter can sit through an outage with no one there to see it.
Boston Backup Power is a division of Boston Automations in Norwood. We design and install RoseWater Energy systems, Savant Power and Generac and Kohler standby generators, and licensed electricians and gas fitters make the connections.
Authorized RoseWater Energy Dealer. Authorized Savant dealer. Authorized Generac and Kohler partner. Updated .
Storms and outages in Nantucket
On April 30, 2024, the 1996 cable went out of service after a roughly 30-second island-wide interruption, and Nantucket ran on a single cable while National Grid worked on it. Losing one cable does not black out the island, but it removes the margin for anything else to go wrong.
The February 2026 blizzard left about 11,000 properties without power at its peak, according to the Nantucket Current, with an 83 mph gust on the island and at least 14 poles down. MEMA counted 7,251 Nantucket customers out at 12:30 p.m. on February 23. The Steamship Authority and Hy-Line cancelled all Monday service, schools stayed closed for power and heat problems, and National Grid estimated full restoration for late Wednesday.
Who supplies the power
National Grid serves Nantucket. The island is fed by two undersea cables, one from 1996 that lands in Harwich and a 38 MW cable from 2006 that lands in Hyannis. Behind them National Grid keeps a backup generator at its Bunker Road power control house and a 6 MW, 48 MWh battery, a project that cost $81 million against close to $200 million for a third cable.
Which system fits a Nantucket home?
We install all three, so we can recommend the one that suits the house and the budget.
Savant Power
For a smaller island house or a cottage that needs a few circuits kept on, Savant Power adds relay modules to the existing panel and Savant Power Storage, which can go indoors where the historic district's exterior review does not reach.
Relay modules in your existing panel and Savant Power Storage batteries, so you choose which circuits get backup power and see your usage in the Savant app. Modules typically run $2,000 to $10,000, and battery backup $10,000 to more than $100,000.
Standby generator
A standby generator can back up either battery system for a multi-day outage. On Nantucket it goes through historic district review because it sits outside, so we plan the location and screening early.
A Generac or Kohler standby generator on natural gas or propane that starts on its own when the power goes out. Most installs run $7,500 to $20,000.
Where the equipment goes in Nantucket
The Nantucket historic district has covered the entire island since 1971, and it regulates exterior changes. Anything visible outside the house, a generator, an outdoor HUB enclosure, a propane tank, goes through that review. A HUB inside the house avoids most of it.
Indoors, a HUB needs a space about 3.5 feet wide, 3 feet deep and 8 feet high, with 36 inches clear in front. A garage or a dry basement above the flood line is usual. For houses near the harbor, in Madaket or on the south shore, we keep it above flood level, because RoseWater's warranty does not cover water damage.
Permits in Nantucket
Nantucket's historic district was set up in 1955 for Old Town and Siasconset and expanded in 1971 to the whole island, Muskeget and Tuckernuck. It regulates exterior changes. We have not found a published rule specific to generators or batteries, so we plan for review of anything that shows outside the house. Electrical work is permitted and done by a licensed electrician.
How to start
For a RoseWater system, start with the Power Plan. For Savant Power, use the Savant quote form. For a standby generator, use the generator quote form. If you are not sure which one fits, use the contact form or call (781) 333-8003 and we will talk it through. We reply within one business day.
Questions about backup power in Nantucket
Do you work on Nantucket?
Do you work on Nantucket?
Yes. We plan each visit around the ferry or a flight, coordinate a licensed island electrician for the connection, and work with RoseWater's technicians when they commission the system.
The island lost a cable in 2024. Would a HUB have helped?
The island lost a cable in 2024. Would a HUB have helped?
The island stayed on during that cable failure, but it lost its spare. A HUB keeps your house running through whatever comes next, whether it is a cable, a pole or a storm, and it cleans up the power the rest of the time.
Will the historic district let us put equipment outside?
Will the historic district let us put equipment outside?
The historic district reviews exterior changes across the whole island. A HUB inside the house avoids most of that. If a generator or an outdoor enclosure is part of the plan, we design for that review from the start.
What does a RoseWater system cost on Nantucket?
What does a RoseWater system cost on Nantucket?
Most RoseWater projects run between $125,000 and $1,000,000, and island logistics are part of the proposal. We give you a written figure after the Power Plan and a site visit.
Ready to plan backup power in Nantucket?
Tell us about the house and what has to stay on. We visit, size the system and give you a written proposal. We reply within one business day.