Somerville Case Profile
April 2026
City of Somerville Networked Geothermal
A community-led feasibility study in New England’s densest city, testing whether networked geothermal can serve as a viable electrification pathway for a grid-constrained urban environment.
⬇ Download PDFProject Description
The City of Somerville is proposing a networked geothermal system in the Central Hill neighborhood, a dense, mixed-use area that includes City Hall, Somerville High School, the Public Library, the 1895 Building, and a YMCA alongside 285 total buildings.1 The system would consist of up to 312 closed-loop boreholes drilled to 500 feet, connected via a thermal energy network to deliver heating and cooling to between 58 and 285 buildings depending on the model selected.1 The feasibility study was funded through a $50,000 HEET Kickstart grant and conducted by Buro Happold in collaboration with drilling contractor Brightcore.1,2
Somerville is the densest city in New England, making it a distinctive test case for urban networked geothermal deployment.1 The city’s aging electrical grid cannot easily absorb rising demand from widespread air-source heat pump adoption, making networked geothermal, which delivers heating and cooling more efficiently and with lower peak electrical draw, a potentially more viable electrification pathway.1,3
Key Actors and Governance
The City’s Office of Sustainability and Environment (OSE) initiated the project, managed procurement, and serves as the primary client, with Energy Manager Garrett Anderson as the public contact.1,4 Buro Happold conducted the feasibility study and techno-economic analysis, while Brightcore Energy handled borefield design and cost estimation.1 Mayor Katjana Ballantyne publicly endorsed the project and framed it as central to the city’s decarbonization goals.2,6
Multiple regulatory bodies hold decision authority. The Massachusetts DPU regulates networked geothermal operators. MassDEP and the EPA co-issue NPDES drilling discharge permits, and the city’s engineering and water departments control local permits.1 Coordination with the MBTA is required for any network routing crossing the Green Line or Lowell commuter rail.1
Funding and Costs
The feasibility study modeled four configurations. Gross costs range from $12.45 million (Model 4, 58 buildings) to $19.02 million (Model 1, 285 buildings). After the federal Investment Tax Credit and Mass Save incentives, net costs range from $5.81 million to $9.22 million.1 Projected annual savings against an air-source heat pump alternative range from $632,000 to $1.43 million, with annual carbon reductions of 474 to 1,130 tons of CO₂.1
The only confirmed funding is the $50,000 Kickstart feasibility grant. No construction funding has been identified, no operator of record has been designated, and no permit applications have been filed as of early 2026.1
Permitting and Approvals
An NPDES permit, co-issued by EPA and MassDEP, would be required for drilling wastewater discharge, with an estimated cost of $25,000–$30,000 and a timeline of three or more months.1 Local permits include a hydrant permit ($200 plus $2,200 refundable deposit per hydrant), an Engineering Department soil disturbance permit ($2,500 per drilling site), and street occupancy and trench permits.1
Significant constraints include a state law restricting drilling within 50 feet of a water tunnel, which eliminates greenspace near the Somerville Public Library.1 The MBTA Green Line and Lowell commuter rail running through Central Hill require close coordination, and underground utility locations must be confirmed via ground-penetrating radar before drilling can proceed.1
Community Engagement and Equity
The OSE distributed materials to approximately 890 households and held two virtual town halls in December 2024 and January 2025, each with roughly 100 attendees, followed by a public results meeting in March 2025.1,4 A resident survey gathered approximately 220 responses, though results were never published.1
Equity is woven into the project rationale. Site selection used HEET’s LeGUp mapping tool incorporating environmental justice and energy burden data, and HEET directed nearly 50% of its total Kickstart funding to environmental justice communities.1,2 Providing cooling access to Central Hill residents who currently have none is an explicit co-benefit.1 More than two-thirds of Somerville’s population are renters, and geothermal is framed as a solution to transformer upgrade costs that fall disproportionately on renters and affordable housing residents.3
Why This Case Matters
Somerville demonstrates that Massachusetts has created strong policies and incentives for networked geothermal, but the practical systems needed to build these projects are not ready yet. The city has a technically sound study, a preferred site, four modeled configurations, and a cost range, but no construction funding, no designated operator, and no permit applications filed.1 The feasibility-to-construction gap here is not primarily technical. The challenge is institutional: deciding ownership, operations, financing, and whether traditional utility rules can be adapted for a city that wants to manage this differently.1
Sources
- Buro Happold / Brightcore, “Somerville Networked Geothermal Feasibility Study,” February 24, 2025. PJ6_Feasibility_Study_01.pdf
- HEET, “13 Massachusetts Communities Kickstart New Geothermal Networks,” February 29, 2024. PJ6_HEET_Blog_Funding_from_MassCEC.pdf
- Buro Happold, “Somerville Networked Geothermal and Electrification Feasibility Study,” March 31, 2025. PJ6_Feasibility_Study_03.pdf
- City of Somerville, “Help Somerville Explore New Clean Energy Technology,” November 26, 2024. PJ6_News_Article_04.pdf
- City of Somerville, “Somerville Report Finds High Cost of Electrification,” May 12, 2025. PJ6_News_Article_03.pdf
- City of Somerville, “Mayor Ballantyne Delivers State of the City Address,” January 8, 2025. PJ6_Mayor_State_of_the_City_Address_01.pdf
- City of Somerville, “Community Climate Action Plan.” PJ6_Somerville’s_Community_Climate_Action_Plan.pdf
- City of Somerville, “Buildings and Energy.” PJ6_Buildings_and_Energy.pdf
- City of Somerville, “Networked Geothermal Informational Meeting,” December 9, 2024. PJ6_Presentation_Slides.pdf
- City of Somerville, “Certified Climate Leader Community,” May 7, 2025. PJ6_News_Article_05.pdf
- “Department of Public Utilities Issues Order 20-80,” December 6, 2023. PJ6_Press_Release_01.pdf
Sources still needed: Resident survey results (~220 responses, not published); any City Council discussion or vote related to the geothermal proposal; documentation of operator-of-record deliberation.