Geothermal Energy at the U - Past, Present and Future
By: Sarah Buening (UofU) July 13, 2023
The University of Utah is responsible for operating nearly 300 buildings that support education, healthcare, research and housing. Powering this infrastructure demands a high influx of energy and, indeed, the majority of the U’s carbon footprint comes from maintaining buildings. However, the U has demonstrated a commitment to pursuing clean energy. In fact, the university has pledged to achieve carbon neutrality by 2040. As the transition to renewable energy sources continues, geothermal will remain an important part of the conversation.
U.S. Secretary of Energy Jennifer Granholm visited the U in early February and praised the geothermal infrastructure it has established to-date, calling geothermal the “holy grail of clean energy.” With the DOE’s support in funding geothermal research and the U’s commitment to sustainability, we foresee a bright future for geothermal energy on this campus. The university’s Facilities Management department has many opportunities for further development on their radar — proving that our progress as a sustainable university is far from over. So, what does the progression of geothermal energy look like at the U?
Geothermal Electricity for the U
The U has one of the “largest long-term green power contracts of any U.S. university.” It’s also one of only 143 institutions worldwide to earn a STARS Gold rating or better in a measure of sustainability assessment. Through a 25-year Financial PPA contract with Cyrq Energy, a Salt Lake City based company, the U receives 130,602,000 kilowatt-hours of geothermal energy per year — also purchasing some geothermal energy from the Soda Lake Field in Nevada. As of 2020, this contract made the U the first public college in Utah to receive more than half of its electricity through renewable sources.
According to Lissa Larson, Associate Director from the Sustainability and Energy team within Facilities Management, 45% of the U’s electricity usage came from geothermal during the 2022 fiscal year. Upon the completion of Castle Solar in southern Utah — which should become commercially operable in September of this year — renewable sources are forecasted to power 71% of the U’s electricity needs. The U’s pending Climate Change Action Plan will highlight the university’s and President Randall’s continued commitment to minimizing our carbon footprint. Looking forward, Larson said, “The university is evaluating our shared infrastructure systems, including opportunities for ground source and thermal storage systems at a campus-wide scale.”
Current Geothermal Heating and Cooling on Campus
In 2018, the U completed its first geothermally heated and cooled building on Campus: Gardner Commons. What began as a student-sponsored project took off and permanently changed the energy portfolio of this university. John Palo, District Manager and U Facilities Safety Committee Chair for Facilities Management, spoke to how the building’s unique design made this feat possible.
Plans for the Gardner Commons building initially focused on using energy-efficient building materials and conditioning systems. By using locally sourced and recycled materials, the university cut down on what carbon would’ve been required to transport materials long distances. Trading a traditional heating and cooling system for a variable refrigerant flow (VRF) technology also allowed the building to save on energy and building materials costs.
VRF systems don’t have to move air more than a few feet before recirculating it back into classrooms. By sprinkling heating and cooling units throughout the building, Gardner Commons needs less than one-tenth the air movement of a similarly sized building. VRF also allows for more usable space within a building. Because it requires very small ductwork, the height of floors in VRF buildings are typically shorter than in buildings with large ducting. The incorporation of this design, according to Palo, allowed the building to use about “40% less electricity than the same building using your traditional heating and cooling system.” Over the lifecycle of the building, the money saved from this building plan allowed the university to install a geothermal field.
The geothermal field consists of a system of heat pumps that use water circulated through 151 enclosed wells in the field loops beneath the soccer field to the east of the Alumni building. The heat pumps extract heat from geothermal energy stored in the ground, amplifying and transferring the heat to its destination. During the winter, Palo said, it takes a small amount of electricity to move water through the ground field loop — a network of underground water pipes. In the process, the water absorbs geothermal heat and produces an output of almost 1,400 kilowatts of energy. “We were getting 87 times as much energy from the geothermal field as it was costing us to move the water,” Palo noted, “But we have further improved on this with minor sequencing changes to how the system operates, resulting in even further savings.” Overall, the heat pumps save about $70,000 in energy costs, 1.8 million gallons of water and 378 tons of carbon dioxide per year.
What’s the U Doing Next?
Now, students and faculty at the U are eager to replicate Gardner Common’s success. We have many potential avenues for expansion to pursue. For instance, the existing geothermal field has the capacity to hold 14 sub fields. Only 10 currently exist, which is already more than Gardner Commons needs by itself. As it stands, the U has the capacity to connect more buildings to the existing heat pump loop, as well as build four more sub fields — thereby expanding the capacity of the existing field by 40%.
Unlike the water source system in use at Gardner Commons, air source conditioning systems fall short in that they either put heat into the air or pull it back out of the air when they experience a need to heat or cool their spaces. Dumped heat cannot transfer between floors or parts of the building that operate on different units. Even without these limitations, the geothermal source system at Gardner Commons still experiences a net heat excess that is transferred to the ground, causing it to potentially warm up over time. Palo noted that a closed-loop system might help utilize that wasted energy. Some buildings on campus have the infrastructure to use a chilled water system for temperature regulation. Chilled water systems use chilled water to absorb heat from the building’s spaces before dispersing it outside. But, with the advent of newer, exciting technologies, the water loop can also be utilized to heat spaces.
Even in the winter, Gardner Commons becomes excessively heated when many students occupy the building during class time. The higher the population of people inside of a building, the more body heat is generated. It might take some additional engineering, but Gardner Commons could dump some of its excess heat into the chill water return loop to help heat other buildings on campus — including buildings which become less occupied during the day. The existing heat pumps could help this process by transferring more heat into the chill water system that could then get used by neighboring buildings. In essence, the heat given off by the people in Gardner Commons in the winter time could be transferred to other buildings to heat less densely populated buildings.
The U is not the only university trailblazing the path toward carbon neutrality. Colorado Mesa University (CMU) uses a geo-exchange system to heat and cool 70% of its buildings, saving $1.5 million a year on energy costs. Because of this success, CMU is expanding the system to all new construction on its campus and exploring options to expand the system into its surrounding community. Colorado Governor Jared Polis has recognized geothermal as a lower-cost option for residents and a potential way to even help reduce tuition for students. He also recently paid a visit to the Utah FORGE site in Milford! The U has the ability to replicate some of CMU’s successes, as well as build on our own. Continued innovation will also open doors to many further opportunities. As Utah FORGE works to make enhanced geothermal systems commercially viable, who knows what might become possible down the road?
The University of Utah will remain an institution that favors progress and innovation for many years to come. The DOE’s and the U’s faith in geothermal energy is not misplaced, but only heading toward exciting new heights. With enhanced geothermal systems on the horizon, the future looks especially bright.