Denver Plans Geothermal and Sewage Heating

Why this is here: Denver hopes to capture roughly four times the heat used by its current steam system during winter from warm wastewater—a potential source of “clean” energy.

Denver officials are planning a new heating and cooling network for eleven city-owned buildings, utilizing geothermal energy and treated wastewater. The city aims to move away from its aging, fossil fuel-dependent steam system, which has seen customer bills double in the last decade. Denver’s “ambient loop” will circulate water between buildings, using heat pumps to transfer energy for heating or cooling as needed.

The project will repurpose the Cherokee Boiler House, a historic brick building, as a central hub for the network. City planners also intend to drill hundreds of geothermal boreholes and install heat exchangers in major sewage lines to capture additional energy. The estimated cost for the decade-long buildout ranges from $280 to $320 million, funded through city dollars and state grants.

While a 2025 feasibility report suggests the loop could be up to 75% cheaper than other decarbonization methods, significant funding may require bonds or private investment. The system’s success hinges on connecting enough buildings to create a stable energy loop and effectively harnessing geothermal and wastewater heat. The work continues as Denver seeks a cleaner energy future.