The local utility company, Eversource, in Framingham, Massachusetts, has kicked off a pilot project to connect roughly 40 buildings, including low-income apartments, single-family homes, small businesses, and the neighborhood fire station, to a networked geothermal system.
The idea for the pilot project came from HEET (Home Energy Efficiency Team), a nonprofit focused on climate solutions that originally started working with the utility to try to reduce methane emissions from gas leaks. But as they looked at the bigger challenge—the fact that ultimately the world will have to transition away from gas to meet climate goals—they started thinking about how basic infrastructure also needed to change at a fundamental level.
“In Massachusetts, we are still investing billions of dollars in new [gas] pipes,” says Zeyneb Magavi, co-executive director of HEET. “That really made us very worried. Here we were investing in new pipes that take 40 years to pay off, and there was a clear mandate that we couldn’t use most of it past 2050.”
Thanks to new incentives from some states and the Inflation Reduction Act, a growing number of homeowners are beginning to install heat pumps. Most homeowners who make the switch use “air-source” heat pumps that pull energy from the outside air to warm the home’s interior. (Yes, this works even in cold weather.) But it’s even more efficient to capture heat from underground, where the temperature is constant year-round. And if a group of buildings share this type of geothermal system, the method can also be cost effective.
In Framingham, Eversource will use a looping pipe system that reaches hundreds of feet below street level. In the winter, liquid flowing through the pipe is warmed by the underground temperature and then brings that energy up into heat pumps in buildings. In the summer, excess heat from the buildings is sent back underground, providing air-conditioning. Electricity from the grid, which is also moving toward renewable energy, powers the heat pumps and is used to move the liquid up and down the street in the shared pipe.
Homeowners who wouldn’t have been able to afford geothermal heat—which might cost $40,000 in a single-family home installation—can take advantage of the business model that utilities use whenever they install infrastructure, in which all ratepayers slowly pay for the cost of improvements over time.
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