Geothermal networks: The next business for natural gas firms

Posted: March 10, 2025

Electric heat pumps have outsold gas furnaces in the U.S. over the last few years, and the trend is on track to continue internationally as many countries incentivize their installation. But, that doesn’t mean natural gas companies are out of a job.

Companies with expertise engineering, building and monitoring underground pipe networks are finding new business connecting whole campuses, neighborhoods and towns to shared ground-source heat pumps in what are called thermal energy networks (TENs), geothermal networks, or district energy systems.

For example, the leading natural gas contractor in New England, R.H. White, contracted with Eversource Energy to build a first-of-its-kind geothermal network in Framingham, MA. Eversource tapped R.H. White because of its expertise in excavating and installing HDPE and carbon steel pipes for natural gas distribution.

The pipe network it laid in Framingham carries a mixture of water and antifreeze to heat and cool 37 buildings. As Eversource collects data to optimize the system over the next two years, R.H. White is contracted to continue assisting with operations and maintenance.

What is networked geothermal? 

Networked geothermal systems, like the one in Framingham, use heat pumps to transfer heat between buildings and the ground.

Unlike gas furnaces, heat pumps can both heat and cool buildings by extracting heat from one location and moving it to another using a piped antifreeze solution of water and glycol. They come in two varieties: air-source heat pumps exchange heat between a building’s interior and the outside air, and ground-source pumps exchanging heat with the earth’s crust, two to 100 meters below the surface.

Ground-source heat pumps are most efficient because, below the frost line—about 3 meters in most locations—the ground stays around 13 degrees C (55 degrees F) all year. When temperatures dip below 13 degrees in the winter, a heat pump can extract heat from the ground and transfer it to a building’s interior. When temperatures rise above 13 degrees in the summer, the heat pump can transfer heat out of the building and sink it into the cooler ground.

Ground-source heat pumps circulate a water-glycol solution through closed loops of pipe either laid horizontally about 2-3 meters below the ground, or in vertical loops about 100 meters deep, depending on ground conditions and the space available. A heat exchanger located in the building transfers heat between the circulating water-glycol mixture and a coolant. Because they require extensive excavation, installing ground-source heat-pumps is a significant upfront cost for individual home or business owners.

Geothermal networks defray that cost by connecting multiple buildings to just one underground closed-loop system, delivering geothermal heat transfer as a utility. Not only does connecting multiple buildings in a network make installation more cost-efficient, it makes the entire system even more energy efficient. When multiple buildings are connected to the pipe loop, it can transfer heat between buildings as well as with the ground. So, for example, a geothermal network can pull heat out of a walk-in freezer at a restaurant and transfer it through the underground pipe loop to heat a residential apartment next door.

What are the benefits of thermal energy networks?

Geothermal networks pay off with increased energy efficiency along with reduced carbon emissions and utility bills. In Massachusetts, where winter temperatures hover below freezing, the yearly heating bill for an average house with a gas furnace is above $1,000. The same house would cost only about $500 to heat with a heat pump on a geothermal energy network.^[1]

 
Geothermal networks have already clocked in at five to six times more energy efficient than the most efficient gas furnaces on the market. And because they only operate on electricity, as grids decarbonize, their operating carbon cost will approach zero. Moreover, the underground pipe systems can last over 100 years, which makes them an outstanding long-term investment for municipalities and campuses.

How are natural gas companies constructing geothermal networks?

Eight U.S. states have already passed laws allowing public gas utilities to add geothermal networks to their portfolios, and several more have legislation pending. In the U.S., some 100 college campuses have already installed geothermal energy networks, and nearly 50 military bases, municipalities and commercial projects have installed them as well.^[2]

HEET, a non-profit that advocates for transitioning natural gas companies into energy network companies, has helped to create a network of nearly 30 gas utilities—covering over half of all U.S. gas utility customers—that are exploring constructing geothermal energy networks.

Meanwhile, all the trades required to build geothermal networks—drillers, pipelayers, HVAC installers and electricians—are experiencing shortages. Drillers in particular are in high demand for installing water wells and gas pipelines. It’s particularly difficult to expand the number of drillers because new drilling businesses must invest in expensive equipment and there are limited spots in the two-year apprenticeships needed to train new drillers. Natural gas utilities may have an advantage entering the geothermal market because they often already have access to many of the necessary trades.

As a U.S. Department of Energy report from January 2025 makes clear, constructing geothermal networks requires coordinating engineers and builders from across different sectors. Contractors and EPCs who can facilitate these supply chain links will be crucial for getting geothermal networks up and running.

^{[1] Applied Economics Clinic, When heating with gas costs more. p. 19 
[2] U.S. Department of Energy, Pathways to commercial liftoff: Geothermal heating and cooling. p. 27, fig.16.}