In an effort to meet College President Phil Hanlon’s 2017 goal of reducing campus-wide greenhouse gas emissions by 50% by 2025 last month, the College began testing four locations for potential geothermal wells. The drilling team has already tested two geothermal wells — one between Maynard parking lot and Kellogg Hall and another northeast of Scully-Fahey field — and is currently drilling in the Thompson parking lot before moving on to drilling in the northwest corner of the Dewey parking lot.
Geothermal energy is key to emission reduction, according to sustainability director Rosalie Kerr, who added that Dartmouth has traditionally burned No. 6 fuel oil — a classification of the type of oil burned — at a central power plant. The steam released from this fuel source is both environmentally unfriendly and inefficient, she said.
“For the last 100 years or so, we have heated our buildings by burning No.6 fuel oil, which has negative climate impacts for a variety of reasons,” Kerr said. “One is that steam is thermally unstable so it’s difficult to have it function at maximum possible efficiency as you move it around campus.”
The identification of a sufficient geothermal well could lead to the creation of a geothermal well field that can provide renewable energy to campus buildings. A geothermal well system relies upon the heat transfer between the different thermal energies of the relatively constant subsurface temperature of the Earth and campus buildings to heat or cool buildings based on the temperature difference with above ground temperatures. In the winter, for example, the thermal energy contained in the ground, which is relatively warmer than the thermal energy above ground, can be transferred to buildings to heat them. A similar process in the summer uses the relatively cooler thermal energy from the ground to cool buildings.
According to associate vice president of facilities operations and management Frank Roberts, the drilling tests are collecting data from the drill sites to determine the energy potential each geothermal well has. As opposed to oil, which can be burned anywhere, the energy potential of a geothermal well is largely dependent on the nature of its subsurface composition.
According to Kerr, subsurface substrates — which the drilling team collects from thermal imaging or sensing equipment — have different energy capacities and therefore different abilities to provide heating or cooling. Consequently, some drilling locations can conduct heat more easily than others. Drilling on different sites will reveal which subsurfaces will allow for the greatest extraction of geothermal heat from the drill holes, Roberts said.
“We need to know the information about the potential capacity before we invest in geothermal [energy],” Roberts said.
According to Roberts, geothermal energy allows for heat transfer technologies to operate at a lower temperature, which allows for less energy that was created to be lost, creating greater “flexibility” in the College’s energy systems. By using the hot water in geothermal wells instead of steam from burned oil, the College can improve energy distribution by 20% across campus, Roberts said.
Although energy reform has been a focus for the College since the 1990s, according to Roberts, the first test for potential geothermal wells on campus occurred in 2019 on the Green, which showed that the land under the Green could be used for geothermal heating and cooling.
“We have achieved 27% carbon emission reduction since 2010, mostly done through increasing energy efficiency,” Roberts said. “Many old buildings on campus use steam and it’s an aging technology which makes us question whether we want to reinvest in older technology or try something [new] like geothermal.”
Jhujhar Sarna Th ’23 said that he believes transitioning to geothermal energy now is a step in the right direction.
“I think geothermal is a good sustainable solution for producing energy,” he said. “If Dartmouth is able to find a way to utilize geothermal [energy], it would definitely work toward our renewable energy coals and decrease carbon emissions. I think [the transition] is something that would make all the young engineers and energy enthusiasts excited.”
Beyond purely decreasing emissions, the geothermal test wells on campus also aim to increase options in the energy system on campus, according to Roberts. Kerr also said that she believes that the current flexibility — although expensive — will be worthwhile.
“Transitioning is a significant cost and Dartmouth’s energy is likely to be one of our largest financial commitments as we go forward,” she said. “But I believe that what you get is a resilient and flexible energy system that will last long into the future.”
Besides geothermal energy, Dartmouth has implemented other methods of transitioning away from burning fossil fuels on campus in specific buildings, Roberts added.
“We have systems in our chemistry buildings where we capture heat that’s being exhausted through water mediums,” Roberts said. “The new [Center for Engineering and Computer Science] building is operating on hot water and not steam … In the future, we want to produce energy through geothermal, though it will be a phased project.”
Kerr added that a large proportion of student residences pose a challenge for producing green energy, but she said she remains optimistic nonetheless. She also said that Dartmouth’s transition is indicative to the rest of the world that a sustainable energy transition is possible.
“Dartmouth is a microcosm of everywhere around the world and I think we have an incredible opportunity to think about our energy system and how we want to operate stability over time,” Kerr said.