instead of flammable and planet-warming gas, those pipes will carry water or other liquids that transfer heat from underground — or from other buildings and sources in the network — that can be used by heat pumps to keep buildings warm.

Heat pumps, which operate like reversible air conditioners, are much more energy-efficient than fossil-fired furnaces or boilers. They’re even more efficient when they can exchange heat and cold with fluid at a stable temperature, rather than from cold outside air, as the more common air-source heat pumps do.

The U.S. Department of Energy estimates that ground-source heat pumps reduce energy consumption and emissions by up to 44 percent compared to air-source heat pumps and 72 percent compared to standard air-conditioning equipment.

I didn't know anything about this but it's truly amazing - it really should be the case that all new utilities in any area that meets the right criteria should be required to provide heating in this way.

As it stands, utilities are basically public in the US entirely (correct me if I am wrong), and it is even the case that many people complain that it's so regulated that they have to sell their green energy back to the utilities company instead of using it themselves... There really should be no barriers for making it a necessity for utilities companies to go this route.