Cornell University is exploring geothermal heating as a sustainable method to warm its Ithaca campus. The project, titled Earth Source Heat, proposes to circulate initially cool water through subsurface reservoirs, where it will be naturally heated by the warmer temperature of the rocks. The project is a research collaboration between faculty, staff, and students across several science and engineering departments with the campus facilities staff.
I joined the Earth Source Heat Research Team as a technical assistant from July 2018 to April 2019, and was responsible for assisting in risk mitigation analyses, identification and characterization of reservoirs, student volunteer coordination, and design and maintenance of the Deep Geothermal Heat Research website.
Risk Mitigation Analyses
We deployed several geophysical techniques to map the subsurface under Cornell’s Ithaca campus, including aero-magnetic surveys, gravity methods, and active and passive seismic reflection surveys. We used these techniques to create detailed three-dimensional subsurface maps, and identify any pre-existing planes of weakness that may be reactivated as a result of Earth Source Heat operations.
Lateral discontinuities in mass density of the subsurface are registered as anomalies in the gravity expressed at the surface. I assisted Dr. Franklin G. Horowitz in conducting a gravity survey over a 10km by 10km grid around the city of Ithaca. We measured gravity at almost 400 stations using a Scintex CG5 gravimeter with a median precision of 23 micro gals. We analyzed the data using a potential field Poisson wavelet analysis. Frank’s report can be found on Cornell eCommons. More information about the project can be found on the Deep Geothermal Heat website.
We deployed an active reflection seismic study to determine whether the subsurface beneath the eastern section of Cornell’s campus was similar to the area already mapped by historical industrial surveys. We deployed 400 receivers over the eastern section of campus. Each node was programmed with GPS locations and then buried in shallow holes. Our vibroseis energy source was a specially designed truck called the T-Rex. The truck was operated by scientists from Network for Earthquake Engineering Simulation (NEES) at UT Austin, a national network of large-scale labs that assist with studying the effects of earthquakes and tsunamis on buildings and bridges. Results can be found in this report on Cornell eCommons. More information about the project can be found on the Deep Geothermal Heat website.
Reservoirs are rocks that are suitable for the slow passage of fluids through pore spaces. Our project began with little knowledge of the characteristics at depth. Information from proximal boreholes were used to identify which geological formations had favorable properties. Secondly, “outcrop analogues” were studied, that is, we looked in areas where the rocks expected below Cornell crop out at the surface, to learn the properties of the rocks at those locations. My involvement in the outcrop analogue studies included mapping of large scale fractures in the Adirondack Mountains, where crystalline basement rocks are exposed at the surface. For areas of greater interest (Whiteface Mountain, Mount Marcy, Ausable Canyon), I used publicly available LiDAR data to map fractures in greater detail. In addition to “remote mapping”, I also mapped fracture orientations in Ausable Canyon.
Conference Contributions and Resulting Publications:
Geological Society of America’s 2018 Annual Meeting: HOROWITZ, Franklin G., KHAN, Tasnuva Ming, BOEDO, Emily, MORUZZI, Samantha A. and GUSTAFSON, J. Olaf (2018). A Gravity Survey Nearby Cornell University Looking for Structures Potentially Interfering With a Proposed Geothermal Campus Heating Project. Recent Advances in Using Near Surface Geophysics to Solve Geological Problems Session.
American Geophysical Union Fall Meeting 2018: Horowitz, F.G., Khan, T. M., Boedo, E.F., Moruzzi, S.A., and Gustafson, J.O. (2018). A Gravity Survey Nearby Cornell University Looking for Structures Potentially Interfering with a Proposed Geothermal Campus Heating Project. Geoscience and Sustainable Energy Solutions Posters Session.
Final Gravity Report by Dr. Franklin Horowitz: Potential Field Surveys, Analyses, and Interpretation for Cornell’s Earth Source Heat Project
Final report by May, Daniel; Brown, Larry; Gustafson, Olaf; Khan, Tasnuva Ming: Seismic Studies in Support of Earth Source Heating at Cornell University: Stratigraphy in the Vicinity of ESH Candidate Drill Sites from Multichannel Seismic Reflection Profiling in 2018.
Proceedings World Geothermal Congress, Iceland (2020): Tester, J., S. M. Beyers, J. O. Gustafson, T. E. Jordan, J. D. Smith, J. A. Al Aswad, K. F. Beckers, R. Allmendinger, L. D. Brown, F. Horowitz, D. May, T. M. Khan, and M. E. Pritchard, 2020, District Geothermal Heating Using EGS Technology to Meet Carbon Neutrality Goals: A Case Study of Earth Source Heat for the Cornell University Campus: Proceedings World Geothermal Congress, Iceland, p. 1-22.
Stanford Geothermal Workshop (2019): J. Olaf Gustafson, Jared D. Smith, Stephen M. Beyers, Jood A. Al Aswad, Teresa E. Jordan, Jefferson W. Tester, Tasnuva Ming Khan. (2019). Risk Reduction in Geothermal Deep Direct-Use Development for District Heating: A Cornell University Case Study.