Frequently Asked Questions

Researchers at Cornell believe that Earth Source Heat holds the potential for a new sustainable, scalable solution to heating challenges throughout New York state and across the globe.

While Cornell is ultimately interested in reducing its fossil fuel footprint, the university is also keenly interested in understanding the impacts of technology choices like Earth Source Heat. Ongoing monitoring systems as well as the tests and measurements that will be conducted in the exploratory borehole will contribute to ensuring that the methods used to extract heat from deep within the earth do not created unacceptable risks or unintended impacts. Cornell scientists are committed to studying and addressing these issues in a thorough and transparent manner, developing best practices that will minimize risk and provide guidance for others who might implement this technology.

Cornell’s near-term goal is to drill an exploratory borehole that will allow scientists to better understand if the project is feasible by exploring deep surface rock conditions and heat output. If it is determined that the process could safely and effectively advance, the next step is to drill a demonstration well pair. Eventually, the university would hope to being a phased process to create a full-scale system capable of heating the entire Ithaca campus.

Phase I – 2021 Exploratory Drilling Program

Earth Source Heat advanced for several years through acquisition and analysis of geophysical data, analysis of archived subsurface data from nearby oil and gas wells, and engineering-economic analyses. While the results were promising, the point was reached at which the technical feasibility of ESH could not be further evaluated without measurements of deep subsurface rock conditions, using an exploratory borehole.

In 2020, Cornell secured a $7.2M U.S. Department of Energy grant to drill a borehole to help verify the feasibility of using a novel geothermal energy system to heat its campus buildings. This grant will create a state-of-the art observatory, the Cornell University Borehole Observatory (CUBO), which will allow researchers at Cornell and from around the world to study the physical, geological, seismic and data science of the subsurface beneath Ithaca. What is learned through this exploratory borehole project will be used to make decisions about whether to move forward with additional wells in which to test geothermal water flow and heat extraction. It is expected that drilling and testing of the exploratory borehole will begin during the summer of 2021.

The university hopes to break ground on the exploratory borehole in late summer or early fall 2021. The borehole will be located on Cornell-owned property, by repurposing a small facilities parking lot near Palm Road.

Cornell will host a series of virtual community forums in early 2021 to provide additional details about the first phase of the project. The first forum is on Tuesday, Jan. 20 from 6-7 p.m.

Phase II – Demonstration Well-Pair

If the exploratory borehole is successful, and funding and other necessary permits are secured, the university would next look to drill a demonstration well-pair.

Analysis of data from the exploratory borehole will be used to further characterize the subsurface hydrogeology and determine the nature of any future work to enhance the flow of water through the hot rock, if warranted.

Product design and location

The challenge of harvesting heat submerged deep within the earth and transporting it to more than 250 buildings on campus is exacerbated by the fact that no existing geothermal systems address Cornell’s precise geological circumstance and heating goals. But faculty and facilities engineers do have a conceptual vision of Earth Source Heat.

Cornell can effectively utilize resources across a large temperature range (as low as approximately 60 degrees Celsius, or at least 140 degrees Fahrenheit), although hotter temperatures are, of course, better. To reach underground temperatures in this range, a pair of wells would be drilled. Each well would have a sufficient diameter to accommodate 40 to 80 liters per second of water flow, leaving enough room for thick concrete casing and metal piping. Until more is determined about the rock formations below Cornell’s campus, it is unknown exactly how deep the wells would need to be. Reaching the desired temperature range would likely require drilling at least 2 miles below the surface.

Water would flow down the first well into a deep reservoir, circulating through a network of pores and crevasses within hot reservoir rock and absorbing a portion of its thermal energy. The water would then be pumped back to the surface through the second well.

Once at the surface, the heated water would enter a heat exchanger—two chambers separated by a thin layer of steel—that would transfer heat from the geothermal fluid to water contained in a second, closed-loop system that would then distribute the supply of heat to a network of campus buildings. A facility would safely house the wells, pumps, heat exchangers and most other visible components of the system. After heat is extracted, the well water is available for recirculation to be reheated at the well depth.

A single well-pair will likely be capable of heating a section of campus. It is anticipated that approximately three well pairs would be required to heat the entire Ithaca campus with the incorporation of geothermal heat pumps.

Our initial demonstration well-pair will likely serve about 20% of the current campus heating load. If successful, the final build-out of Earth Source Heat would be optimally sized to deliver the majority of heat needed for campus. However, during very cold weather, an energy system using biomass would be used to supply the additional heating needs of campus. Using biomass for the infrequent peak heating loads would be far more efficient than over-sizing Earth Source Heat. This system would utilize local biomass resources (wood or non-food energy crops, animal waste or food waste) as an energy source.

Cornell has looked at this option. However, the need for this kind of heating would require hundreds if not thousands of heat pumps, a very large geothermal field footprint and significant electricity (which would put the university further behind its goal of a carbon neutral campus). Overall, this solution would not be as financially or environmentally beneficial to Cornell or the region. Additionally, ground source heat pumps are best used for both heating and cooling. Lake Source Cooling already substantially meets Cornell’s cooling needs and is much more environmentally friendly than heat pumps.

No. Cornell would retrofit the existing combined heat and power plant to heat campus using hot water from deep within the earth, thereby eliminating the use of fossil fuels to heat campus. The only new facility would be a pump and heat exchanger facility, similar to, but smaller than, the facility used for Lake Source Cooling. Heat storage tanks or similar supporting facilities could be included in the future, depending on the optimized final design.

Cornell is currently reviewing possible locations for a demonstration well-pair on university-owned property. The university is working with faculty and industry partners to develop site selection criteria, which will include geological and geophysical suitability, the distance from private land and the adjacency to the designated area of campus it would serve.

Currently, Cornell envisions an open-loop system where water from the injection well flows freely through cracks and crevasses in the earth’s subsurface. Findings form the test borehole, however, may dictate that Cornell develop a closed loop system where the water does not come into direct contact with subsurface formations.

Drilling safety

We won’t know whether stimulation is necessary until we have a better understanding of subsurface rock formations which we’ll discover through the test borehole. Should stimulation be required, any activity will be based on the concept of hydroshearing, which is different from the hydraulic fracturing or “fracking” method used for extracting oil and natural gas. While both processes increase fluid pressures, weaken the overall rock mass, and create or enhance fracture porosity and permeability, there are some very important distinctions.

The purpose of hydroshearing is to open up natural, preexisting fractures that are spaced several inches apart through which, later, slowly moving water would mine the heat out of the rock adjacent to the fractures. In contrast, the purpose of hydraulic fracturing during shale gas operations is to break fractures which are spaced much more closely to one another, in order to release a large fraction of the gases that are trapped in tiny pores.

Tests conducted elsewhere show that preexisting fractures can safely be made to open slightly using relatively low water pressures that are sustained for comparatively long times, whereas modern hydraulic fracturing for oil and gas production uses much higher water pressure. Research conducted during the test well and early demonstration phases will be used to determine the specific pressures required.
Most importantly, the Earth Source Heat project will not be producing fossil fuels; it will only be mining heat through transfer from the hot rock deep within the earth.

The target depths for Earth Source Heat are at least five times deeper than the depth of the Marcellus Shale beneath Ithaca and there are several thick, impermeable layers of rock between them.

Water safety

Valuable lessons have been learned from oil and natural gas production about best practices to ensure long-term integrity of the well. Cornell is committed to using only high-quality pipes, casings and other materials to avoid leaks.

The casing process keeps a well open and protects the earth and groundwater, and shores up the wellbore itself. Cement is then pumped down the well and forced up the outside of the steel casing until the well column is sealed. The casing process ensures that the production well is isolated from any freshwater zones and natural gas zones. Cornell plans to drill and case to depths of thousands of feet below the bottom of the water table to access hot rock that is many times deeper than the Marcellus Shale layer.

While casing is important in all wells, there may be some differences between the initial exploratory well and future test and production wells. Deeper parts of the exploratory well may be left uncased for a time so that necessary research can be conducted. Importantly, we do not plan to pump water or other fluids into the test borehole, which will minimize risk of contamination.  

A fully functional well pair will use water from Cornell’s own water treatment plant, with total consumption expected to be much less than what Cornell typically uses in a single day. Should Earth Source Heat become operational for heating the Ithaca campus, water will be circulated through cracks and crevasses in the subsurface with minimal amounts of makeup water needed to replace any water that infiltrates into the deep bedrock. This makeup water will also be from Cornell’s own water service.

All drilling fluids and water from well development and testing will be contained in tanks or lined sumps to prevent infiltration into the soil or aquifer. Any fluids that require disposal will be treated as needed (for example, to remove sediment) prior to disposal at a treatment plant. In addition, Cornell requires robust material storage, waste management, and spill response plans from all contractors in order to prevent environmental impacts.

No. Water injected into the well will not connect to local potable groundwater resources. Freshwater is typically found only at shallow depths (up to several hundred feet), although some studies suggest it is possible there may be pockets of deep freshwater at depths approaching 1,000 feet (still well above the geothermal resources). The proposed demonstration well will be cased and cemented into the ground for at least the first 6,000 feet below the surface, with multiple layers of steel and cement as required to meet groundwater protection standards.

Some water used in the drilling operation will be lost to the borehole; any remaining or returning water will be captured and treated prior to disposal at a treatment plant.

Until Cornell has completed a test well-pair, it is unclear exactly what additives might be needed to develop the geothermal resource. However, Cornell is committed to using only non-toxic materials, to providing complete transparency about any planned chemical additives, to incorporate a safety review of those substances in the environmental assessment, and to incorporate appropriate testing and monitoring into the plan as needed to minimize any potential risk.

Environmental Assessment

Yes. The proper permitting and required studies will be done prior to the drilling of any demonstration or production well-pairs. This will include a review of the broad range of environmental, social, and economic impacts typical of a comprehensive State Environmental Quality Review Act (SEQRA) assessment.


The first drilling phase of the project will involve installation of a test well only. It is very unlikely for this type of drilling to cause a felt earthquake. Should the project advance to subsequent phases, there is a remote chance that moving water through the deep bedrock will cause deep rock to shift enough to be felt at the surface. A number of geologists and engineers are evaluating any risks associated with induced seismicity by actively researching the bedrock in our area to better understand the rock formations under campus and identify any ancient faults. This includes analysis of the “background” rate of small earthquakes resulting from natural forces, and to help identify the location of existing bedrock faults. Installation of the test well will provide critical data about the bedrock geology that will be used to design a drilling program that minimizes the risk of induced seismicity.

The work we are planning is unlikely to create earthquake hazards due to many factors, including the local geology, the relatively low local seismicity of our area, the relatively low pressures and quantities of water we intend to use, and the steady, balanced forces that would be the goal of a successful well-pair system. To reduce any risk even further, we plan a number of activities to better understand our local subsurface systems. Prior to any drilling, we will continue to study the geology, hydrology and natural seismicity using past wells and surface instruments. Next, we will drill a full-depth test well and thoroughly study the geology, hydrology and existing fracture networks that we encounter. State-of-the-art seismic monitoring equipment will be deployed to provide detailed feedback on any changes in the state of stress at depth during all phases of the project. Such monitoring will allow us to carefully plan and control any significant stimulation actions, thus ensuring that the development of our geothermal resources is accomplished as safely as possible. This step-wise and science-based approach can be a model for future development to reduce seismic risks or concerns.

No. Friction, imposed by the weight of rock, will prevent the fractures from growing and extending in an uncontrolled way. Only where water pressure is substantially increased by injection at a well will friction be reduced enough to cause fracture stimulation. As has been recently reported, long-term and continuous forced-pressure water disposal in some areas of the country have created felt seismic events. No such water disposal activities will be part of our system.

Additional Questions

Once the drilling is complete, the site can be restored, with only the very top of the well visible, along with valves and piping from the well. Once connected, a water line between 8 and 10 inches in diameter will run from the well head and underground to a single-story pump and heat exchanger building, similar to, but smaller than, the Lake Source Cooling building by Cayuga Lake, which also houses pumps and heat exchangers. The building would likely be sited somewhere on Cornell property close to the well head.

During the few months of well drilling and development, there would be some noise and lights associated with the operation. Noise would be controlled with baffling and mufflers to meet local noise ordinances and lighting would be directed to the immediate drilling area to provide a safe work environment for the operators. Once the drilling is complete, there would be essentially no light or noise pollution, all pumps would be located within a building and all lighting would meet the local dark sky standards.

No. All wells will be located on Cornell property and within a reasonable distance from local residential areas. As such, adverse effects to local property values are not anticipated.