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What is a geothermal community?

Clean Heat, Clean Air | Educational Building Block #4

Welcome to the Massachusetts Clean Heat, Clean Air campaign educational building block series! This series was created by Mothers Out Front members to share key concepts and terms from our campaign for healthy homes & communities. These building blocks are intended to be short, easy learning opportunities for busy advocates.


What is a geothermal community?

Before we get to the good stuff, a quick refresher on geothermal energy.

Dig deep enough, and the ground is always about the same temperature – say, 55ish degrees. Shallow geothermal systems, aka ground source heat pumps, take advantage of this consistent temperature to provide heat in the winter and air conditioning in the summer.

The earth’s constant temperature can provide both heating and cooling
Image Source: Dandelion Energy

Looks nice if you live in this mansion, right? But a key problem with geothermal is the upfront costs. Drilling giant holes in the ground is expensive! Surprise! Once installed, however, geothermal systems are the most efficient option available for heating and cooling buildings.

Enter: Community Geothermal

In a community geothermal network, many buildings are connected by underground pipes filled with water. These pipes run between buildings while heat pumps within each building extract the temperature the building needs (heating or cooling) from the water. Then the water runs through pipes deep in the ground to restore its temperature. These community systems of networked ground source heat pumps can shoulder high upfront costs because the costs can be shared across multiple customers and over time. These networks are also even more energy efficient than regular geothermal as they can share energy between buildings too – for example, the heat from supermarket fridges can be transferred to homes down the street.

Geothermal neighborhoods are also all-electric, so as our state’s electrical grid gets cleaner, buildings with geothermal systems will eventually be powered with 100% green energy.

And there are many other benefits. Geothermal provides cooling in addition to heating, which will be essential as global temperatures rise. No household combustion means air quality is better. Water is not explosive – unlike gas! – so it’s safer for our homes.

Finally, community geothermal is a great way for entire communities to transition to clean heat, not just the people who can afford it. In other words, this is an efficient and equitable path to building electrification.

Geothermal Community
In a community geothermal network, buildings are connected by underground pipes, similar to how our gas distribution grid works today.

A Path Forward for Gas Utilities

If you’re thinking: high upfront infrastructure costs + shared maintenance costs + expertise putting a bunch of pipes in the ground = a great space for UTILITY COMPANIES you are correct.

In the near future, gas utilities and gas workers could install and manage geothermal networks instead of gas pipes, redirecting investment from gas to geo. The new water pipes powering the geothermal networks are even the same piping material that is installed now for gas, meaning minimal worker retraining for installation, operations, and maintenance.

Gas utilities could get off gas, without workers losing their jobs or customer’s energy bills rising, by becoming non-emitting renewable thermal energy companies.

It gets better – this is actually happening – there are TWO approved and funded demonstration projects….

First Networked Geothermal Neighborhoods in Massachusetts

Geothermal Neighborhood

Image Source: HEET

Eversource has identified many potential locations with enthusiastic participants and is expected to announce their site choice this month. Their goal is to have the demonstration project operational by the fall of 2021. The Eversource demonstration will be located in a denser, mixed-use neighborhood and cover approximately 100 customers.

The second geothermal installation will be in North Andover, Andover, or Lawrence and funded with settlement money from the Merrimack Valley gas explosions. The Attorney General’s Office is managing a grant program to select a company to design, install, and operate the system.

If you are in National Grid territory, they are joining the race too, and have just proposed community geothermal installations four times the size of Eversource’s and explicitly to replace leaky gas pipes. The MA Department of Public Utilities is currently considering their proposal.

The goal is for the networks to expand beyond these first streets. As more sections of gas-carrying pipe are replaced with geothermal energy, these networks can interconnect and serve ever-larger areas, increasing efficiency, reducing costs, and reducing emissions.

This idea is spreading beyond Massachusetts – in April 2021, New York City announced plans for demonstration projects of utility-scale geothermal service and legislative changes to make it possible. Con Edison in New York has funded a demonstration project and Philadelphia, Rhode Island, and Connecticut are also all considering whether Geo might be a grounded path to a just transition beyond gas.

Key Term:

GeoMicroDistrict – A GeoMicroDistrict is the term created by our allies Home Energy Efficiency Team (HEET) to describe a street segment of networked geothermal. GeoMicroDistricts are designed to be interconnected, like Lego blocks, in an ever-expanding grid – or GeoGrid – gradually replacing our existing gas infrastructure with geothermal networks.

Deep Dive:


Meet our Allies: HEET

HEET, or ‘Home Energy Efficiency Team’ is a Cambridge-based non-profit with a mission to cut carbon now by driving systems change. HEET is currently focused on driving the transformation of our energy system beyond gas. HEET identifies high-impact problems that need effective action and then begins reaching out to stakeholders across disciplines, sectors, and social boundaries to learn deeply and build relationships and trust around shared purpose. Together these groups then innovate and iterate, co-creating solutions that work for all, then pilot, evaluate, and verify before sharing and scaling. Learn more at HEET.org.