Key Takeaways

  • Eversource Energy, National Grid, and Unitil have submitted long-term contracts to regulators for three utility-scale energy storage projects totaling 1,068 MW/4,472 MWh, expected to be operational by 2030. The related announcements were made by the utility companies and the Massachusetts Department of Energy Resources last week.
  • The projects include Jupiter Power's 700 MW/2,800 MWh Trimount storage facility, as well as two projects from Flatiron Energy: the 250 MW/1,000 MWh Energizar and the 168 MW/672 MWh Salt Cod. According to the companies, once operational, they will provide clean peaking capacity for the Greater Boston area and southeastern Massachusetts, alleviating transmission congestion—areas where Eversource is piloting localized virtual power plants to ease supply-demand imbalances.
  • These agreements advance Massachusetts' goal of deploying 5 GW of energy storage by 2030. Earlier this year, Democratic Governor Maura Healey announced plans to procure an additional 5 GW of storage by 2035 as part of a broader push to add 15 GW of emissions-free capacity to the state's grid.

Deep Dive

These three projects stem from the first solicitation round of a procurement process targeting transmission-side energy storage projects, requiring individual projects to have at least 40 MW of power capacity, with an overall goal of up to 1,500 MW of battery power capacity.

A fourth project—Rhynland Energy's 200 MW River Mill Storage project—also emerged from that solicitation but has not yet signed long-term contracts with any of the three Massachusetts utility companies. Rhynland did not respond to Utility Dive's request for comment.

The second solicitation round of the current procurement process seeks 250 MW to 300 MW of distribution-side storage projects, with individual projects requiring at least 1 MW of power capacity. According to the Massachusetts Department of Energy Resources, subsequent solicitations will seek a total of 3,500 MW of storage power capacity by July 2030.

Financial analyses submitted to the Massachusetts Department of Public Utilities show that these projects will modestly reduce monthly bills for most customers over the next 5 to 15 years.

Jupiter Power's Trimount is the largest of the three projects that have submitted long-term utility contracts. It is expected to become the largest storage facility in New England by a significant margin once it comes online later this decade.

The project's capacity contracts are allocated as follows: 200 MW to Fitchburg Gas & Electric Light (Unitil's Massachusetts subsidiary) and 500 MW to National Grid's Massachusetts subsidiary. The project will be built on a 20-acre former oil terminal in Everett, north of Boston, connecting to the nearby Mystic substation. Jupiter Power states that the project will enhance reliability, alleviate peak demand, and reduce voltage and frequency fluctuations on the regional grid.

A few miles east of Trimount, Flatiron Energy's Energizar project on a former industrial site in Chelsea will also stabilize the grid and ease peak demand. Flatiron says the project will also help more efficiently utilize locally produced renewable energy. The company targets beginning operations in the second quarter of 2027.

Flatiron expects its Salt Cod project to begin operations around the end of 2028. The project will occupy 11 acres of the Montaup power plant—a coal- and oil-fired facility—on the waterfront in the town of Somerset in southeastern Massachusetts. That plant was shut down in 2010.

Last year, an Italian company canceled plans to build a submarine cable manufacturing plant at the site, as the Trump administration's crackdown on the U.S. emerging offshore wind industry dampened hopes for sustained growth. An earlier analysis by the Massachusetts Clean Energy Center noted that the site is suitable for energy storage equipment as well as manufacturing of offshore wind blades, monopiles, and nacelles.