A new report suggests the University of Hawaiʻi at Mānoa could lower energy costs using shallow geothermal systems. These systems use ground heat exchangers buried near the surface to cool buildings. The Stan Sheriff Center is identified as a possible pilot site. The report notes that Oahu’s terrain and volcanic rock can help move heat away from the underground systems. If placed correctly and funded well, these systems could reduce peak electricity use and save money for public buildings and campuses.
Report Maps Favorable Sites And Uses
According to the NREL, researchers from UH Mānoa’s Hawaii Groundwater and Geothermal Resources Center teamed up with Lawrence Berkeley National Laboratory under the Department of Energy’s Energy Technology Innovation Partnership Project program to produce island-scale favorability maps and a site-specific feasibility study. The group combined 11 GIS layers, including elevation, geology and soil permeability, to rank areas for both closed-loop and open-loop ground heat exchangers. The NREL summary also notes that the analysis folded in community perspectives and cultural considerations when weighing where projects might move forward.
Groundwater Flow Makes Or Breaks Systems
The ETIPP final technical report concludes that in Hawaiʻi’s cooling-dominated climate, ground heat exchangers will gradually add heat to the subsurface, which means they need substantial regional groundwater flow to stay viable over time. Numerical hydrogeologic models were used to estimate how much flow is required to keep temperatures near the boreholes close to ambient and to flag locations where closed-loop systems are the better fit. The full ETIPP report is available through the Department of Energy’s OSTI repository at OSTI.
Stan Sheriff Center Modeling Shows Promise
At UH Mānoa’s Stan Sheriff Center, site-specific modeling showed that a closed-loop ground heat exchanger could run normally in its first year. Without groundwater flow, though, near-borehole temperatures and chiller demand were projected to climb from years two through six. When groundwater flow was included in the models, the system was expected to operate successfully for at least a decade, as reported by the NREL. The report cites the arena’s heavy cooling load and its relatively open surroundings as reasons it was chosen for a detailed pilot analysis. Project authors stress that pairing this type of modeling with on-the-ground hydrogeologic studies will be essential before any drilling or construction begins.
Cold Seawater Offers Another Path
The same report points to cold seawater as another promising way to keep buildings cool, highlighting existing systems that pipe deep, chilled ocean water to serve nearby facilities. The Natural Energy Laboratory of Hawaiʻi Authority has long run seawater cooling infrastructure that supplies chilled water to research and commercial tenants, as detailed by NELHA. That local track record suggests hybrid setups that mix seawater cooling, shallow geothermal systems and conventional equipment may be worth examining for campus and district-level cooling.
Costs, Loans And What Pilot Projects Need
Technical and economic modeling in the ETIPP analysis indicates that geothermal systems could cut electricity use and reduce energy transfer demand, savings that could add up for large campuses. The catch is the upfront price tag. The report finds that capital costs remain a significant hurdle without favorable loan terms or financial incentives. Longer loan periods and grant support improve the outlook for campus-scale systems and make it easier for planners to justify pilot projects on paper. Those techno economic results are detailed in the ETIPP report hosted at OSTI.
Next Steps For Campus And State Planners
UH Mānoa joined the ETIPP program in 2022 to dig into geothermal options, and researchers say the next steps include targeted hydrogeologic field work, reviews of permitting requirements and community engagement before any pilot project moves to funding. Local officials and campus planners are expected to keep an eye out for grant programs and low-cost financing that could push a pilot across the finish line, and the new report offers a roadmap for where to start looking. For broader background on UH’s geothermal efforts and the statewide picture, see the University of Hawaiʻi System coverage at University of Hawaiʻi.
