Harnessing Energy Under Our Feet

Nesjavellir’s ION Adventure Hotel in Iceland. The Millennium hotel in New Zealand. The Chena hot springs in Alaska. All are examples of geothermal energy in use – the use of natural heat underfoot in a sustainable way.

Duke is also evaluating the use of geothermal energy as a sustainable energy source, with initial support coming from the Nicholas School of the Environment and the Nicholas Institute for Energy, Environment and Sustainability. Students and faculty and have been partnering with staff and support from Duke Facilities Management Department (FMD), using the campus as a living laboratory for applied learning about geothermal energy.

The Duke Climate Collaboration Symposium led by the Pratt School of Engineering on Dec. 2 explored the history, opportunities and challenges of geothermal energy – opening with a summary of Duke’s efforts to date.  Speakers for the daylong symposium included Eric Bosworth (Thermal Energy Insights), Lawrence M. Cathles III (Cornell University), Dustin Crandall (U.S. Department of Energy’s National Energy Technology Laboratory), Jeffrey Eppink (Enegis), Frank Horowitz (Consultant), and Laura Dalton and Peter Malin (Duke University).   

How it works: Deep underground, the Earth is hot – very hot. Via drilling, this energy can be exchanged for both heating and cooling. Hot groundwater can be pulled from wells to directly heat buildings. After the heat is used, cooled water is sent back underground, where it heats up again – serving as a reusable, Earth-energy system.  Geothermal heat can also be used in the expansion cycles of chillers for the opposite effect: cooling for air conditioning.

“With shallow geothermal energy, the university could leverage the consistent temperatures present in the ground as a clean energy solution reducing externally-supplied electricity costs and natural gas,” said Dalton, who organized the symposium.“

This symposium is meant to accelerate geothermal energy solutions along the East Coast. Duke burned its last coal in 2011 for heat on campus. Since then, the university has transitioned to other sources of energy. Other universities have already made use of this type of geothermal energy or are currently investigating it.

Professor Emeritus Peter Malin joined Duke University in the 1990s, returning in 2020 after eight years as the director of a geothermal institute in New Zealand.  He noticed potential for geothermal energy at Duke.  In addition to guiding the drilling of two exploratory wells on campus, he integrated them into his applied learning courses.

“The geothermal process is different from oil and gas; the latter pools. For oil and gas, you drill into an area and draw oil and gas out. For geothermal, you are looking for fractures that have high flows of hot fluid. With geothermal, you have to expand the area to capture and expand the heat collected,” Malin said.

Duke’s geothermal potential is grounded in geological history, back to Pangaea more than 240 million years ago. As Pangaea drifted apart into continents, rift lakes and basins formed, hosted volcanos and filled with sediments. Their remnants are strung along the length of the East Coast, Malin said.

Duke University sits on the western edge of one of these basins, bounded by the Jonesboro Fault near RDU airport and the Carolina Terrain to the west. Understanding what is beneath this basin is key to geothermal energy at Duke, Malin said.

Malin’s class, Geothermal Geosciences 590/690, has so far drilled two test sites on campus to come to this conclusion. They worked with Duke FMD in a valued partnership that has helped move the projects forward and provided equipment, staffing, site access, and learning.  At the second Duke site near Chiller Plant II, Malin’s team shifted to air hammer drilling methods to save costs. In October 2025, the team brought in a drilling rig to dig a 2000-foot bore hole, but stopped drilling for technical and financial reasons at 1800 feet.

“Even so, the rock got warmer the nearer we got to our intended depth,” said Malin, who is seeking support for further measurements in this well and future underground exploration. Duke could explore geothermal energy to heat and cool class and hospital rooms, dorms, greenhouses and other facilities.

Cement, water and a few additional materials together form concrete, the material that paves the world. Pratt Assistant Professor Laura Dalton is exploring concrete thermal energy systems, potentially for efficient cooling of a future GPU center. Dalton’s research team is also using 3D printing underwater to create concrete for structural solutions. In addition, she is working with startups like Reefcycle to grow and help test more sustainable bio-cements.

“Concrete is simply engineered rock. It is the most prominent construction material, and it has been around for hundreds of years. It’s the foundation of most of our manmade structures. We could use the concrete around us for energy storage,” Dalton said.

The Dec. 2 symposium explored geothermal from multiple angles – and via multiple examples around the world. While not an energy silver bullet, geothermal has potential – but it also has challenges.

There is also a significant startup cost related to the drilling and building the system. Upon construction, there is a four to five-year timeframe before the system starts to pay back economically.  Speakers said preparation is key. Operational difficulties can occur and heat delivery can fail suddenly if not engineered correctly.  Thus planning, further underground exploration and engineering analysis are needed for the next steps for Duke’s geothermal journey.

The symposium was the fifth of the Duke Climate Collaboration Symposia, a series of convenings designed to accelerate climate solutions by developing new collaborations among Duke scholars and external partners. Each symposium focuses on identifying opportunities for Duke University to make the most of its interdisciplinary expertise and convening power for meaningful impact on climate challenges. 

The series is funded by a gift from The Duke Endowment in support of the Duke Climate Commitment, which unites the university’s education, research, operations, and public service missions to address climate challenges. The Nicholas Institute for Energy, Environment & Sustainability manages the symposia series.