A major networked geothermal project gets underway in Connecticut

New Haven, Connecticut, has broken ground on an ambitious geothermal energy network that will provide low-emission heating and cooling to the city’s bustling, historic Union Station and a new public housing complex across the street.

The project will play a crucial role in the city’s attempt to decarbonize all municipal buildings and transportation by the end of 2030. As one of Connecticut’s first geothermal energy networks, it will also serve as a case study of how well the technology can both lower energy costs and reduce greenhouse gas emissions as the state considers promoting wider adoption of these systems.

The network will use as many as 200 geothermal boreholes. Fluid will circulate through pipes in each of these wells, picking up thermal energy stored within the earth; in hotter weather, when cooling is needed, the systems will transfer energy back into the ground.

The city began drilling the first test boreholes in November. The results were promising: One test hole was able to extend down 1,200 feet, significantly farther than the 850 feet projected, Winter said. If more boreholes can be drilled that deep, it could mean fewer holes are needed overall — and thus less materials — making the project more efficient, he said.

The goal is to have the system up and running in the latter half of 2028. The apartment units, which are still in the design phase, will be connected to the system as they are built.

Even as the initial plan comes together, New Haven is already considering the possibility of expanding the nascent network to include more buildings, such as other apartment units under development nearby, existing buildings in the neighborhood, and a police station around the corner, Winter said.