The Massachusetts legislature is considering a bill that would allow utilities to buy geothermal energy instead of natural gas for heat and hot water. The “Act for utility transition to using renewable energy (FUTURE)” was proposed after a September 2018 explosion in the natural gas system in the Merrimack Valley in northeast Massachusetts. One person was killed and 131 homes and other structures were damaged or destroyed in that catastrophe.
At a Nov. 12 legislative committee meeting, proponents testified about a system that would use geothermal energy in neighborhood-scale district heating systems that would reuse existing utility infrastructure. A nonprofit organization is collaborating with utility companies to move ahead with what’s being called the GeoMicroDistrict system.
Under a contract with Boston-based nonprofit Home Energy Efficiency Team (HEET), U.K.-based BuroHappold Engineering conducted a feasibility study for development of the GeoMicroDistrict. The feasibility study concluded that the system “re-purposes the existing public utility structure, financing, workforce and customer base to deliver safe, clean and affordable heating and cooling.”
The GeoMicroDistrict system would be installed and operated using existing right-of-way, says Alexan Stulc, BuroHappold sustainability specialist. It would consist of vertical boreholes for the ground-source heat pump and an ambient water loop that would connect to the customer’s building.
At the legislative hearing, gas utility Eversource described a geothermal network demonstration it has proposed to the Dept. of Public Utilities to run over the next three years to see whether the geothermal network loops could be used as an alternative or as an addition to the natural gas system, says Michael Goldman, director of regulatory, planning and evaluation for Eversource.
The utility proposes to install the network loops in three distinct settings, “reflective of what we would find out in the field if we’re able to scale this up,” he says. The scenarios include multifamily buildings, such as apartment buildings; dense urban or mixed-use, e.g., a mixture of commercial and industrial that might also include residential; and a purely residential neighborhood.
The system will use ground-source heat pump technology, which uses electricity to transfer heat from the ground to a network of hot water pipes, to provide heating, and potentially cooling, for the buildings within each district, BuroHappold officials say.