Exploring Earth Source Heat
What is Earth Source Heat?
What is Earth Source Heat?
Earth Source Heat (ESH) is our version of an enhanced geothermal system (EGS) that would use earth’s internal heat to warm our campus. Wells would be drilled into “basement rock” where the internal heat of the earth keeps temperatures near or above the boiling point of water. Water circulated through the wells returns to the surface as hot water for campus heating and potential electricity production. Cornell’s faculty, researchers and engineers are exploring a hybrid system that would use bioenergy to meet supplemental heating needs during sustained or extreme cold spells.
Our scientists believe that the project holds potential for a research-driven solution that, if proven viable, could lead to a scalable solution globally, making exploration of this technology an ideal candidate for our campus. While Earth Source Heat is extraordinarily promising, this approach has not been pursued in our region and remains one of uncertain costs and ultimate feasibility.
Why is Cornell exploring earth source heat?
ESH has been part of Cornell’s Climate Action Plan (CAP) since 2009 as a potential means of moving toward carbon neutrality on campus by eliminating fossil fuels for campus heating. The CAP includes dozens of targeted solutions, including energy conservation and improvements to supply efficiency. Due to the size of our campus, Cornell needs a new, innovative solution to sustainably meet heating demands.
It is widely agreed that there is enough natural heat within the earth to sustain us indefinitely, and drilling technology advancements allow us to access this heat. While similar projects have succeeded in other areas, this type of project has never been attempted at a location with the conditions present in upstate New York. These challenges and potential issues require thorough and thoughtful examination – making this an ideal research project for a multidisciplinary university like Cornell.
Our faculty and staff have extensive expertise in developing renewable energy systems and have studied large-scale geothermal systems around the world. This expertise, combined with our history of creating and deploying new energy systems on campus (such as Lake Source Cooling), make Cornell exceptionally well suited to explore this technology.
While Cornell is ultimately interested in reducing our fossil fuel footprint, we are also keenly interested in understanding the impacts of technology choices like Earth Source Heat and helping to ensure that methods used to extract heat from deep in the earth do not create unacceptable risks or impacts. Our 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.
What is the goal for earth source heat?
What are the other potential benefits of implementing such a system?
Drilling, Water, and Seismicity
Enhanced geothermal systems use water to stimulate cracks in underground rock. How is this different from fracking associated with natural gas and oil production?
An early phase in Cornell’s Earth Source Heat project is the drilling of a test well. Analysis of data from the test well will be used to further characterize the subsurface hydrogeology and determine the nature of any future work to enhance the resource, if warranted.
The anticipated stimulation is 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 at lower overall pressures sustained for a longer time compared to hydrofracking. Research conducted during the test well and early demonstration phases will be used to determine the specific pressures required.
Most importantly, we will not be producing fossil fuels, but hot water and steam heated by 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.
How do I find out more about the Vibroseis trucks used to understand rock formations?
Cornell’s Ithaca campus is where our core education mission and commitment to sustainability intersect. We have a longstanding tradition of using our campuses as “living laboratories” where faculty, researchers, students and staff advance academic research by creating, testing and implementing a variety of solutions to real-world challenges.
Currently, Cornell is exploring Earth Source Heat (ESH), our version of an enhanced geothermal system that would use earth’s internal heat to warm our campus. Wells would be drilled into “basement rock” where the internal heat of the earth keeps temperatures near or above the boiling point of water. Water circulated through the wells would return to the surface as hot water for campus heating and potential electricity production.
As we move into the next phase of research, faculty and students from the College of Engineering will perform passive and active seismic testing essential to the critical task of understanding rock formations beneath campus. This research involves the operation of one vibroseis truck and approximately 400 small self-recording geophones (nodes) along the routes shown below. Geophones are small, electronic receivers designed to pick up seismic vibrations below the Earth’s surface. Data gathered by the geophones will allow researchers to gain a more accurate view of the rock formations beneath the surface.
What is a vibroseis truck and why is it important to this project?
A vibroseis truck is a mobile acoustic energy source, roughly the size of a dump truck, that will create low-frequency signals by applying a vibrating pad to the ground for several seconds at regular stops along the route. The nodes will record the acoustic reflections from various rock formations, allowing us to infer critical details about the subsurface conditions.
What is the timeline for this activity?
The activity is tentatively scheduled to begin on Sept. 21, 2018. The vibroseis truck will be deployed for 5 to 7 days over roughly 5 to 6 kilometers of roadways on Cornell property and in the towns of Ithaca and Dryden. While the university is only considering Cornell-owned land for a potential project site, it is necessary that we create a wide grid for testing to provide adequate imaging of existing rock formations.
Should the local community anticipate any disruptions (i.e. noise, traffic, etc.)?
Deploying vibroseis trucks is a common part of drilling exploration. They are non-intrusive and have been used in Tompkins County in recent years without incident, therefore we do not anticipate any disruptions. The truck is mobile and stops along the road every few yards or so to lower its pad and execute the sequence of vibrations, which takes less than one minute per location. Anyone close to the truck may hear or feel a slight vibration. Any traffic impacts will be minimal, similar to following a school bus or garbage truck.
Were any permits required by local municipalities?
Faculty and engineers from Facilities and Campus Services met with local road authorities and municipal leaders to discuss the vibroseis survey and obtained permits, where necessary. Cornell is in the process of notifying residents along the vibroseis truck route of the dates for the activity, and also any landowners where we may place a temporary geophone to collect data.
How will the data be assessed to determine if a site is viable for an ESH test well?
Ideally, the data collected will provide us with enough information to identify fractures or faults at depth that will guide us on specific locations to target (or avoid) for development of a test well. Once the initial results are compiled and analyzed, we will determine what additional research may be necessary.
As with other academic research, our researchers will evaluate and publish their own analysis of the data, after which it will be released to the general public. Drilling will only occur after we seek and receive all requisite governmental approvals and permits.
Will chemicals be injected into the well?
How are wells constructed to protect ground water and avoid other problems?
We have learned valuable lessons from oil and natural gas production about best practices to ensure long-term integrity of the well. We are committed to using only high-quality pipes, casings and other materials to avoid leaks.
The casing process keeps the well open and protects the earth and groundwater. The hard metal casing shores up the wellbore and extends throughout the well to assure the long-term integrity of the well from end-to-end. Cement is then pumped down the well under pressure and forced up the outside of the steel casing until the well column is sealed. The casing process ensures that the producing well is isolated from any fresh water zones and natural gas zones. We will drill and case to depths 9,000 feet or more below the bottom of the water table in the Ithaca area to access hot rock that is at least five times deeper than the Marcellus.
How much water will be used and where will it come from?
Will any water that we are injecting enter the local watershed?
No. Water injected into the well will not connect to local groundwater resources. The proposed demonstration well will be cased and cemented into the ground for at least the first 8,000 feet below the surface, with multiple layers of steel and cement as required to meet groundwater protection standards. 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 our geothermal resources).
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.
What measures will Cornell take to protect surface water resources?
Will an environmental assessment of the impact of drilling a test well be completed before a test well is constructed?
What research has Cornell been doing to prepare for drilling a test well?
A first step toward gathering better geological data for the Ithaca area began in 2015 when Cornell engineers buried 12 seismometers across the campus to measure seismic activity over the course of a year. While the data is still being analyzed, researchers anticipate that it will give them a better idea of where geological features relevant to geothermal production are located below campus. This would allow engineers to choose locations to conduct more sophisticated experiments such as active seismic surveys, in which Vibroseis “thumper” trucks send vibrations into the ground, resulting in an acoustic, three-dimensional view of what lies below.
In addition, a 2016 Cornell study presents a statistical analysis of a large portion of the Appalachian Basin. Faculty and graduate students from three different Cornell Engineering departments rigorously pored through data generated by the fossil fuel industry, examining nearly 40,000 drilling locations throughout much of New York, Pennsylvania and West Virginia. Informed by oil- and gas-well logs, the scientists were able to map which regions were most likely favorable for direct-use geothermal energy.
Ultimately, we will not know exactly what we are going to find at such depths until the initial test well is drilled. That is why the project will have a series of safety benchmarks. If these benchmarks are not met during each phase, the project will not move forward.
Is the Earth Source Heat demonstration project likely to cause damaging or felt earthquakes?
How will Cornell mitigate the possibility of earthquakes from project activities?
Can stimulated fractures grow in an uncontrolled way?
Project Location and Design
How would the proposed system work?
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.
To reach underground temperatures of ~100-150 C (~200- to 300-degrees Fahrenheit), 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, it is unknown exactly how deep the wells would need to be. Reaching the desired temperature range would likely require delving 3 to 5 kilometers, or 1.8 to 3.1 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—essentially two chambers separated by a thin layer of steel—that transfers heat from the geothermal fluid to water contained in a second, closed-loop system that would 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 depth.
The well pair would only be capable of heating a section of campus; we anticipate that approximately four to six well pairs would be required to heat the entire campus.
Where will ESH be located?
Cornell is currently reviewing possible locations for a demonstration well on university-owned property. We are working with faculty and industry partners to develop site selection criteria, which will include geological and geophysical suitability, distance from private land and adjacency to the designated area of campus it would serve.
What will the well site look like?
Will there be light or noise pollution?
Will the project adversely affect local property values?
Will the project be sized large enough to handle the full heat load for campus?
Will you need to build a new heat/power facility?
What is the timeline for this project?
We are currently in the first or preparatory phase. Faculty, students and engineers have started the initial planning, including research to better understand the rock formations beneath campus. These efforts are being led by some of the premier experts in geology, seismicity and renewable energy production in the world. This research, along with refining system design, applying for necessary permits, determining an exact location, securing funding and continued public outreach will take a minimum of two years.
After a successful preparatory phase, Cornell would hope to move into phase two with the installation of a single test well on Cornell property that would provide the best understanding yet of the ground beneath campus and what a full-scale system might require.
If the test well produces viable results, a third phase would seek to install an adjacent well and heat-exchange facility, creating a small-scale demonstration project that could heat multiple buildings within a section of campus. It’s expected to take about six years to complete all three phases and if successful, a full-scale project could then be implemented over the next 10 years.
What stage is the project in?
Our Community Engagement
Community engagement is an essential component of any large-scale project. That is why Cornell faculty, staff and administrators regularly meet with on- and off-campus groups to provide updates on our carbon neutrality goals.
Earth Source Heat has been part of Cornell’s Climate Action Plan since 2009. During a detailed review of our energy portfolio and options that fit within the academic mission, ESH was identified by a working group of faculty and staff as the best option to reach carbon neutrality on the Ithaca campus by 2035. During fall 2016 and spring 2017, the working group conducted extensive outreach to on- and off-campus partners, including a community forum in downtown Ithaca. That outreach has continued into 2018 and will be a standing part of the project for its duration.
While many in Ithaca and the surrounding communities are supportive of clean energy development, as evident in the Tompkins County Energy Roadmap, we understand that this type of project has not been attempted in our region before, leaving many questions about its feasibility and scope. As an academic institution with deep faculty expertise in emerging energy technology, seismicity, geology and the environment, Cornell is uniquely suited to explore ESH. Even if we are not able to fully implement ESH, we will still gain valuable knowledge about rock formations beneath campus as well as possible system designs that could be beneficial to other institutions, businesses and communities considering this technology.