With the historic agreement of the COP21 summit in Paris in December 2015, the international community collectively resolved to keep the rising temperatures under 2 degrees Celsius. It marked the world’s commitment to tackling global warming and encourages research and innovation would that keep the earth sustainable for future generations.
With the renewed interest in lowering world temperatures, and the rapid depletion of fossil fuel reservoirs, it is important to look towards newer sources to fulfill the world’s energy requirements. Alternate energy resources like solar and wind power have been important allies in the strive to sustainability. An unconventional source of energy that has not received as much attention, however is geothermal energy.
Geothermal energy, as the name suggests, is the energy made from the heat inside the earth’s crust. ‘Geo’ is greek for earth, and ‘thermos’ means heat. According to UCA USA, the most common form of geothermal energy available for use is “to tap into a naturally occurring hydrothermal convection.” What this essentially means, is that water from the surface seeps into the crust and get heated up. This heated water can then be pumped up to the surface to be used as needed.
As Prof. Teresa Eileen Jordan, earth and atmospheric sciences, explained, geothermal energy is everywhere because everywhere below the Earth’s surface, the temperature of rocks increases downward. But the cost of extracting this energy differs from place to place as their geological properties vary.
In the past, geothermal energy has been used to generate electricity since it is the most cost effective. However, more direct ways of using this energy exist — for heating buildings, for enabling industrial processes or for assisting agricultural opportunities (for instance, greenhouses and aquaculture.)
“For this direct-heat approach, much lower temperatures are needed, which greatly expands the areas for which it might be cost effective,” Jordan said. “District heating systems using geothermal heat exist in hundreds of communities in Europe, as well as in Boise, Idaho.”
The fact that it is more practical to tap into geothermal energy in some places than others led to a joint study between Cornell University, Southern Methodist University and West Virginia University with support from the U.S. Department of Energy.
“If all locations have some degree of potential, but achieving the potential to extract energy will be much easier (including lower cost) in some places than others, then the DOE wanted to have guidance on where to invest its time and energy to conduct research and assist with development,” Jordan said.
The study points out the places in New York, Pennsylvania and West Virginia which are more economically and geologically suited to benefit from geothermal energy. These regions are shown in the map below.
Image courtesy of Prof. Teresa Jordan
Map showing Geothermal Fairplay Analysis results.
The study assumed that the end-use of this energy would be district heating systems, in which homes in a community are supplied hot water through a set of interconnected pipes. The large population and high heating demand across New York, Pennsylvania, and West Virginia would translate into economic advantages and reduced carbon emissions if geothermal heating was to replace heating using fossil fuels.
The study, which was a part of DOE’s Geothermal Play Fairway Analysis, looks at the important questions that a corporation or a town might have when trying to make a decision to invest into geothermal energy : how far do we need to drill to get the suitable temperature? (reservoir); do conditions facilitate the natural plumbing of the rocks? (thermal); is there a risk of inducing earthquakes? (seismic) and where can the population best use the resource? (utilization).
Image Courtesy of Prof. Teresa E. Jordan
Deliverables based on existing data
Comparing these factors, the study was able to indicate regions where more research is warranted to decide whether to undertake a demonstration project. The accompanying graph (featured image) highlights most favorable towns in the three states studies, and how these risk factors affect them.
Even though, Ithaca does not make the list of favorable towns, Jordan said that she believes that this study provides encouragement to researchers to further study this resource as it applies to Cornell.
“The three-state Geothermal Play Fairway Analysis that we completed contributes to knowledge about the geothermal resources in Tompkins County, where Cornell is located,” Jordan said. “That regional study has helped us to clarify what additional information is needed near Cornell.”
Jordan admits that a community’s commitment to advancing geothermal energy will be an important factor in the final utilization of the resource. The amount of capital required for digging wells, even test wells, is huge. Also, there are no regulations in place that facilitate the widespread usage of geothermal energy extraction for district heating systems.
“The geological variability will need to be matched by human cleverness and commitment if the aspiration to use geothermal energy as a major energy source anywhere across our study area, including Cornell, is to move reality.” Jordan said.
Jordan also said that President Elizabeth Garrett’s decision to move away from the 2035 date for a sustainable Cornell impacts her research in a subtle way.
“Counter-intuitively the impact is that it encourages my research … I interpret President Garrett’s hesitation regarding the 2035 date to be an endorsement of the importance that we [need] geoscientists [to] conduct research that will help to reduce the uncertainty,” Jordan said. “With that new information the Cornell facilities specialists and Cornell research engineers will be better able to analyze potential extraction strategies and designs for the use of this energy.”
Jordan also said that an important aspect of this study was the DOE’s insistence on using data that was already available since the purpose of the Play Fairway Analysis is to identify locations where the expense of collecting more data is most justified.
“So for any location where a user group is interested in testing the viability of a geothermal heating system, whether in what this study identifies as a high priority or low priority area,” Jordan said, “much more exhaustive and detailed study must be conducted of the factors examined here as well as study of other factors.”