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Marblehead Municipal Light Department has achieved 74% carbon-free electricity in 2025, the result of a historic 23-percentage-point surge in 2024 that positioned the town as a leader in Massachusetts’ clean energy transition.
The department jumped from 42% carbon-free in 2023 to 65% in 2024, marking its largest single-year gain in history. The momentum continued into 2025, putting Marblehead ahead of its target of 70% by 2028 and on track for 85% by 2033 and net-zero emissions by 2040.
The breakthrough represents more than a decade of methodical planning that began with the town’s 2010 investment in Berkshire Wind, according to Jonathan Blair, MMLD general manager.
“I think the way that Marblehead has gone about it and sort of been more systematic at building it into the portfolio is a way to get lasting, lasting change,” Blair said. “So I’m encouraged about our current position. I’m encouraged by the trend.”
Marblehead’s approach differs significantly from utilities that achieve carbon-free status through paper transactions alone. Blair explained that renewable energy certificates, or RECs, can be bought and sold separately from actual electricity, allowing any utility to claim 100% renewable energy through financial transactions costing roughly $2 million to $3 million annually.
“We could just buy, you know, a single stroke of the pen a financial transaction could make Marblehead, or any other entity, 100% renewable,” Blair said. “But that also makes it easy to undo. It’s kind of, maybe at the federal level, it’s akin to, like, executive orders.”
Instead, Marblehead has pursued what Blair calls legislative action in power procurement.
“And what we’re trying to do to continue the analogy is take, like, legislative action whereby we’re actually, like taking the long, difficult road to find and acquire long term carbon free contract or assets,” he said.
The town’s carbon-free portfolio draws from nuclear power stations including Millstone in Connecticut and Seabrook in New Hampshire, which provide steady baseload electricity. Hydroelectric sources include New York Power Authority Hydro, Hydro Quebec, FirstLight Hydro and Brookfield Hydro. Wind generation comes from Berkshire Wind facilities and Hancock Wind, while the MSGT Cotton Solar Project in Ludlow contributes solar power.
Marblehead owns an 11% stake in the Cotton Solar Project through qthe Massachusetts Municipal Wholesale Electric Company, giving the town direct oversight of the 35-acre facility’s operation and maintenance.
The 2024 surge followed key contract additions. New hydroelectric agreements with FirstLight Energy and Brookfield Hydro added more than 13,800 megawatt hours of carbon-free electricity. Nuclear generation from Millstone increased 22.9%, rising from 12,704 MWh in 2023 to 15,616 MWh in 2024.
The town also completed a certificate exchange with NextEra Energy, which operates Seabrook Nuclear Plant, increasing officially recognized carbon-free electricity by nearly 6,800 MWh at no additional cost.
A 2021 state law change helped accelerate Marblehead’s progress by allowing nuclear power to qualify as emission-free energy, distinct from the renewable energy category that excludes both nuclear and large hydroelectric facilities. This administrative distinction matters less to residents than actual environmental impact, Blair noted, explaining that the town focuses on carbon emissions rather than regulatory classifications.
The shift away from unspecified commodity power purchases toward named carbon-free generation sources now represents 30% of Marblehead’s portfolio, marking a major change in procurement strategy.
Average wholesale power costs decreased 3.4% year-over-year from 2023 to 2024, dropping from 11.28 cents per kilowatt hour to 10.9 cents, creating what officials describe as a scenario where cleaner energy costs less.
Challenges remain in the town’s clean energy transition. The light department continues exploring sites for a 5-megawatt battery storage facility to reduce peak demand costs and provide backup power during outages. Officials estimate such a system could save approximately $382,000 annually in capacity costs.
Finding space for the battery installation presents difficulties in the densely built town. The department must also navigate increasingly complex peak demand management, calling 84 potential peak events in 2024 compared to an average of 40 to 50 in previous years.
Marblehead’s relationship with Hydro Quebec currently supplies 6,588 MWh annually, accounting for roughly 5% of total electricity load. Officials are considering doubling that allocation in future contracts.
The town set its net-zero target for 2040, a decade ahead of the 2050 deadline Massachusetts law requires for municipal light plants.
