Art by Sofie Koski

In 2017, the Town of Carbondale adopted the goal to achieve a 100% reduction of carbon emissions by 2050. While that may sound ambitious, Carbondale is steadily taking steps toward carbon neutrality, with the next right beneath our feet.
Carbondale’s Third Street Center is already an epicenter for binding sustainability and community, with its solar array producing over 100% of its energy needs every year. However, the building isn’t quite net-zero. While the building may keep its lights on with solar, the heating still comes from natural gas. That’s why on April 24, the Center will host an open house for its proposed geothermal heating project, which aims to provide sustainable heating and cooling for the Center itself as well as a 16-acre district encompassing the Carbondale Library, Bridges High School, and townhomes on 2nd Street.
Titled “Heat Beneath Our Feet,” the free event will begin as a closed workshop available to industry professionals before transitioning to a family-friendly open house. Both the workshop and the open house will be led by the Carbondale Community Geothermal Coalition (CCGC), which includes the Town of Carbondale, Roaring Fork School District, Carbondale Library and Third Street Center-based sustainability nonprofit Clean Energy Economy for the Region (CLEER).
While the CCGC was formally created to apply for a Department of Energy grant — which awarded $716,000 toward an ongoing geothermal feasibility study in November of 2023 — the parties which comprise the CCGC have been working in tandem since 2018.
In 2018, the Carbondale Board of Trustees asked CLEER to explore the possibility of creating a Zero Energy District (ZED) in Carbondale.
A ZED can both drive down unit costs for energy and infrastructure, as well as provide benefits to buildings which may not be able to independently achieve net-zero status due to constraints of their structure or property size. After some exploration, CLEER proposed the aforementioned 16-acre district as a site for the creation of a ZED.
This project isn’t like what most people think of when they hear “geothermal,” which might look like a single deep borehole all the way down to magma. Instead, the project will utilize a much more common and easily accessible resource: the ambient temperature of the ground.
Soil maintains a relatively cool and constant temperature, which is why in the olden days, food was preserved in underground cellars. Ground-source heat pumps can tap into that ambient temperature and harness the earth’s thermal mass: in the summertime, excess building heat can be pumped into the ground where it will dissipate, and conversely, heat can be drawn out of the earth and pumped into buildings in the wintertime. This is performed using a network of underground water pipes as well as a field of narrow boreholes which, once installed, will be invisible on the surface.
Not only is this sort of system cheaper for individual buildings, it’s also easily expandable: just dig more holes and connect more pipes.
The goal of the project is to construct a community thermal energy network which would not only provide Carbondale with an expandable source of efficient heating and cooling, but demonstrate to the industry and the U.S. Department of Energy the feasibility of such a network in a town like Carbondale. While similar systems already exist — the nearest one on the campus of Colorado Mesa University — this project will be the first system of its kind designed for a small rural community.
CCGC is still awaiting funding from a second round of DOE grants to actually build the system, and while funding will determine the project’s timeline, Carbondale is well on its way to becoming a nationwide model for geothermal infrastructure.
For those interested in learning more, CLEER encourages community members to attend the Third Street Center’s “Heat Beneath Our Feet” event on April 24 from 5 to 7pm. A Spanish translation will be available, pizza and snacks are provided and Aspen Science Center will host a science activity for kids.