Table of Contents
If you’ve used our coverage to follow utility costs, planning decisions and public safety details, that’s the work Marblehead needs year-round. We run on $80,000 a year, with 95% going to journalism. If you’ve been meaning to support independent local reporting, join today so we can keep this coverage free and keep building toward 100 members by Dec. 31. Click here to become an Independent member
Summer heat waves pushed the Marblehead Municipal Light Department’s peak electricity demand to an all-time high of 34 megawatts in 2025, and commissioners are now reviewing a battery storage proposal that could reduce wholesale power costs by approximately $500,000 annually.
General Manager Jonathan Blair told commissioners Dec. 16 that peak demand has grown volatile while overall power consumption remains flat at roughly 100,000 megawatt-hours per year.
System peak demand reached 34 megawatts this year, compared with 27 megawatts in 2023 and 31 megawatts in 2024.
Blair said the spikes occur during two- to three-day periods of extreme heat when air conditioners run continuously.
The department pays approximately $1 million annually in wholesale transmission and capacity charges calculated based on regional peak demand. Those costs are spread across total kilowatt-hour sales.
Want the key town stories without the noise? Sign up for our newsletter for clear weekly updates on boards, budgets and what’s changing in Marblehead — no spam. Sign up for our once-a-week newsletter.
Battery project under review
The light department is reviewing a proposal from Lightshift, a developer working through the Massachusetts Municipal Wholesale Electric Company, to install a utility-scale battery at the Village 13 substation.
The system would store 20 megawatt-hours of electricity and discharge up to 5 megawatts during peak demand periods.
Blair said the battery is projected to reduce costs by roughly $500,000 per year. Under the proposed financial structure, savings would be split approximately evenly between the light department and the developer.
The project would require no upfront investment from the department.
The battery would be placed within the existing fenced area at the substation. Blair said the department is coordinating with town planning and conservation officials on permitting.
Three agreements under review
Commissioners are reviewing three governing documents.
The land use agreement defines site terms. Blair said the department is coordinating with the Water and Wastewater Department because the substation sits in a shared utility corridor.
The interconnection agreement establishes electrical protections and triggers a regional study through ISO New England, the grid operator. Blair said the study typically takes several months.
The energy storage service agreement governs financial terms, liability, insurance and decommissioning.
Blair said the developer would contribute 5% of estimated decommissioning costs annually, fully funding a trust by year 20. Insurance would cover risks during earlier years.
Commissioners asked whether the structure adequately protects the town during the first decade when the decommissioning fund balance remains lower. Blair said the developer is exploring options including short-term performance bonds or enhanced insurance.
Fire safety coordination
The department has briefed the fire chief and fire prevention officer on emergency response scenarios.
Blair said the primary concern involves thermal venting, in which the battery overheats. Firefighters would isolate the unit, cool surrounding equipment and allow the battery to burn out.
The systems cannot be extinguished with carbon dioxide or water. Fire truck access has been confirmed, and a fire hydrant will be installed in coordination with the Water Department.
Blair said fire officials have indicated they are not opposed to the project.
Timeline
The department expects to bring the energy storage service agreement to commissioners for consideration at the Jan. 27 meeting.
All three agreements include provisions allowing the department to withdraw if electrical studies reveal problems, site conflicts arise, market conditions change or local ordinances ban battery storage.
Blair said Planning Department staff are reviewing permit requirements. Conservation Commission review may be required, though utility projects are typically exempt. The department plans outreach to conservation officials.
