Cornell’s exploration of the feasibility of using deep geothermal energy to heat the Ithaca campus has reached an important milestone, with the completion of drilling for the Cornell University Borehole Observatory (CUBO ).
Drilling at the nearly two-mile Deep Drilling Observatory, located on a Cornell-owned gravel parking lot near Palm Road, began June 21 and was completed August 13.
CUBO provides a platform to directly study the temperature, permeability and other characteristics of rock deep beneath the Ithaca campus – factors that will help the university determine whether to move forward with a proposed plan to heat the Ithaca campus with Earth Source Heat (ESH). In addition to providing critical ESH-related information, the observatory is designed to persist as an ongoing resource to showcase and enable Deep Earth exploration and experimentation.
An ESH system would extract naturally heated water from the basement, transfer its heat to a separate water supply circulating in the campus heating distribution pipeline, and return the original water to the basement, where it would warm and start the cycle again.
CUBO’s drilling – overseen by Campus Facilities and Services in conjunction with university faculty, National Renewable Energy Laboratory staff and experienced geothermal consultants – reached a depth of 9,790 feet below the sub -soil, reaching the crystalline rock of the basement. The CUBO team conducted a comprehensive testing program, involving the collection of cuttings and cores and the use of geophysical instruments to measure rock properties, describe temperature and stress conditions underground, and identify fractures which can allow the flow of water and the exchange of heat. In addition, by changing the water level in the well, they were able to assess the permeability of the subsoil.
Early data appears to confirm researchers’ earlier expectations of the quality of the geothermal resource at a depth range between 7,500 and 10,000 feet: a combination of rock temperatures between 75 and 100 degrees Celsius and little permeability except that controlled by old fractures in the rock. These conditions imply that an improved geothermal system – a technology currently at the center of US Department of Energy research – will be required to use geothermal heat for campus heating.
“The CUBO project was an enormously significant undertaking – whether measured in time, personnel or money – that taught all Cornell participants valuable and often unexpected lessons from day one to the last,” said the co -PI of the project Terry Jordan, the J. Preston Levis Professor of Engineering Emeritus. “We are delighted that our geological predictions were substantially accurate – it was helpful – but more importantly, we are delighted that the new data provides many insights into the system of solid rock, fractures, pressures and fluids in depth under the campus. We can replace the “assumptions” that we were forced to use before with real knowledge. And because of the collaborative nature of CUBO, if additional wells are drilled for an Earth Source Heat demonstration, Cornell will be much better able to partner effectively with industry drilling experts.
The greater Ithaca community will have a chance to learn more about the future of ESH at Cornell when the university hosts its fifth ESH Town Hall, November 3 at Phillips Hall from 5:30-6:30 p.m.
Since CUBO only provides scientific information and will not be used for heat generation, the data is currently being analyzed to determine if the university could move forward with drilling a pair of separate wells as a demo for ESH.
In addition to heating the campus without using fossil fuels, ESH would enable the university to achieve its goal of carbon neutrality for the Ithaca campus by 2035, while providing a blueprint for other heat applications. geothermal energy in the Northeast and other parts of the United States.
The project, which was launched with a $7.7 million grant from the US Department of Energy, has already generated considerable interest in the scientific community. In August, several members of the CUBO team and their collaborators presented their research at the Geothermal Rising Conference in Reno, Nevada.
A presentation, “Investigating Performance of Geothermal Reservoirs With Bi-Directional Heat Transfer for Seasonal Thermal Storage Using Thermal-Hydraulic Reservoir Simulations”, explored, with numerical simulations, the possibility of using a deep geothermal reservoir at Cornell to store heat residual produced by campus activities during the summer months, to conduct the ESH in the winter. Modeling demonstrated how waste heat could be used to realize a thermal battery storage system, increasing the efficiency and longevity of a geothermal heating system.
Another presentation, “Innovative Thermal Strategies: Electrification’s Best Friend,” showed the cost advantages of using ESH over other thermal electrification strategies that have been proposed to help the New York State to achieve its goal of a 100% carbon-free network. The document reports that in addition to meeting Cornell’s needs, ESH could reduce the capital costs of renewable electricity and battery storage by approximately $300 million to “green the grid,” compared to to conventional air-source heat pump technologies.
“For the participants of the CUBO project – students, facility staff and faculty – the ‘CUBO summer’ has been intense, stressful, fun and very helpful,” said Jordan. “It took the interdisciplinary expertise of this team and the dedicated interest of outside industry experts to bring this vision to fruition. And this partnership will continue to be necessary to design and build a successful ESH demonstration project.