Solar panels estimated to save towns $78K over 30 years

Contractors reshingle the roof of the Deer Isle Town Hall in 2024 for solar panels. PENOBSCOT BAY PRESS FILE PHOTO

THE ISLAND— Solar panels and battery storage systems are set to be installed at public buildings in Deer Isle and Stonington.

The projects are fully funded by a $200,000 state grant, split equally between the two towns. When the systems are operational, Deer Isle and Stonington officials say the solar systems will cut costs while making the buildings more energy-efficient during power outages.

Both towns are working with the Bar Harbor-based solar contractor PV Maine to design and install the systems.

Deer Isle’s panels will power its town office building, while Stonington’s system will power its former elementary school, now office building.

Stonington Economic Development Director Linda Nelson presented PV Maine’s design at a Stonington select board meeting on March 17. Nelson said the system will use roughly 600 square feet of solar panels, mounted on a carport in the parking lot of the old elementary school. A cable will run underground from the panels to a battery storage system in the basement of the building.

PV Maine estimates Stonington will save $36,000 on electricity over the 30-year lifespan of the solar panels. As an added benefit, Nelson said the system will power the three-story building during an outage, saving money for the town on propane for its stand-by generator. The solar system’s output and estimated savings will be broadcast live to a screen in the lobby of the building.

PV Maine estimates the project will cost $99,700, which will be completely covered by Stonington’s half of the shared state grant.

“This is a pilot project,” Nelson said at a March 17 Stonington select board meeting. “If we didn’t have the grant maybe we wouldn’t do it, but there’s no town money in this.”

In Deer Isle, Town Manager Jim Fisher said the panels will be mounted on the recently reshingled roof of the town office. The lithium iron phosphate batteries—which Fisher said are safer and more stable than typical lithium-ion batteries—will be stored inside the building.

Over the 30-year lifespan of Deer Isle’s panels, PV Maine estimates the town will save $42,000 in electricity. The full project will cost an estimated $99,580, according to PV Maine’s design proposal.

Like Stonington’s system, Fisher said Deer Isle’s batteries will power the building during a power outage. The building’s generator can also charge the batteries directly, which Fisher said could save the town money on generator use during an extended outage. If the outage is short enough, Fisher said the generator may not have to run at all.

“We would be off the grid at night and through most of the day,” Fisher said.

The town office is heated by electric heat pumps and an oil furnace. If the solar system is paired with additional heat pumps, Fisher said the town could also save money on heating oil each year.

Getting off the ground

The two towns received the state grant May 2024 and chose PV Maine’s bid in November. In Deer Isle, Fisher said the town has “everything we need” to start the project. When PV Maine starts mounting panels and installing batteries, Fisher said the entire project could be done in just a few days.

“I’d like to move quickly,” Fisher said.

In Stonington, the town is waiting on the approval of a federal environmental permit, a process which Nelson said could take three to four months.

“The permitting process is slow,” Nelson said. “We’re kind of in a waiting game at this point.”

Nelson said the permitting process is required because Stonington’s panels are ground-mounted. When the process is complete Stonington can move ahead with installation.