In the frame of the Massachusetts Clean Energy and Climate Plan for 2050, the Department of Public Utilities has required utility providers to demonstrate decarbonized alternative solutions, particularly for heating*. In this context, Eversource Energy believed a network geothermal solution as applied to a mixed-use neighborhood to be the best alternative solution for implementation. In collaboration with the City of Framingham, a pilot installation was identified to ensure the decarbonization of heating within a neighborhood, while meeting the requirements of this plan. The chosen system must limit the use of gas—and reduce its carbon intensity—while offering at least the same comfort and financial cost as the current solution. This technological choice will enable the buildings that make up the city's future eco-district to benefit from a year-round heating and cooling solution powered by the Earth's energy.
A request was also made to minimize our impact to the community during drilling. Thus, one of the primary challenges in delivering the geothermal borefields was not to shut down the parking lot of the district's community college during construction.
* SDSN (2021), Massachusetts 2050 Decarbonization Roadmap, mass.gov
As a part of Eversource Energy's pilot project, the Celsius Energy system was implemented in three separate geothermal borefields located in strategic areas of the community linked by a 1-mile geothermal loop (green line in the illustration). The geoenergy system connects more than 30 buildings including a secondary school, a fire station, shops, apartment blocks, and single-family homes.
The geoenergy system, consisting of a ground source heat pump, will be commissioned in spring 2024 and will exploit the relatively constant temperature of the subsurface and the Earth's thermal storage capacities to provide sustainable heating to the connected buildings in the winter. During the summer, the system will extract heat from the buildings and store the thermal energy in the ground, effectively cooling them. As the majority of buildings in scope for the project did not have robust cooling equipment in place to address the heat of summer, the native cooling offered by the geoenergy system is another highly valued benefit of the solution.
Thanks to a pyramidal design, the innovative geoenergy system made it possible to carry out the drilling work with a small footprint that enabled the parking lot to remain accessible for faculty and students during the school year. This innovative design also shortened the construction schedule by reducing the number of boreholes as compared with traditional vertical drilling methods and enabled a 74% reduction in surface piping and related earthwork, made possible with co-located drilling.
Networked geothermal systems, like the one built by using SLB's Celsius Energy solution and its partners in Framingham, offer new low-carbon opportunities for heating and cooling neighborhoods, higher education campuses, and commercial building complexes. With investment support from the Inflation Reduction Act, SLB sees this project in the US as a model that could be duplicated and applied in other cities, towns, and states to achieve their decarbonization goals, as the world moves toward a more sustainable energy future.
Eversource Energy is the project developer and energy provider for the City of Framingham. RH White Construction is the provider of construction management services and installer of the distribution network. Berkel & Company Contractors, Harris Exploration, and Midwest Geothermal are collaboration partners for the drilling of the geothermal borefields.
Support for this project also includes CDM Smith as the engineer of record and Home Energy Efficient Team (HEET), a nonprofit organization committed to promoting green energy in the US.
