Colgate Feasibility Study Geothermal
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A Feasibility Study of Geothermal Heating and Cooling at Colgate University Trevor Halfhide, Seghan MacDonald, Josh McLane, and Sarah Titcomb December, 11 2009 Department of Environmental Studies Colgate University 13 Oak Drive Hamilton, NY 13346
description
Feasibility Power Plant
Transcript of Colgate Feasibility Study Geothermal
A Feasibility Study of Geothermal Heating and Cooling at Colgate University
Trevor Halfhide, Seghan MacDonald,
Josh McLane, and Sarah Titcomb
December, 11 2009
Department of Environmental Studies Colgate University
13 Oak Drive Hamilton, NY 13346
Contents:
Project Overview: ............................................................................................................... 2
Introduction to Geothermal Energy: ................................................................................... 2
Types of Geothermal Energy:............................................................................................. 4
Shallow ........................................................................................................................... 4
Deep ................................................................................................................................ 7
History of Geothermal Use: .............................................................................................. 10
Feasibility of Geothermal Energy at Colgate: .................................................................. 12
Costs.............................................................................................................................. 13
Electricity...................................................................................................................... 20
Geology......................................................................................................................... 21
Valuation of Benefits .................................................................................................... 27
A Condensed List of the Potential Benefits of Geothermal at Colgate: ....................... 30
Hamilton College Comparison ..................................................................................... 32
Potential Funding .......................................................................................................... 33
Potential Obstacles........................................................................................................ 35
A Condensed List of the Potential Barriers of Geothermal at Colgate:........................ 36
Conclusions:...................................................................................................................... 37
Acknowledgements........................................................................................................... 38
Appendix I: ....................................................................................................................... 39
Appendix II: ...................................................................................................................... 40 Appendix III:..................................................................................................................... 45
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Project Overview:
The goal of this paper is to explore the feasibility of geothermal technologies on
Colgate’s campus. This document is by no means an all encompassing study, but serves
as a preliminary step forming the foundations for future research. We ultimately
conclude that geothermal heating and cooling is a very feasible option for Colgate and
that vertical, closed-loop shallow systems have the most potential. This is the best
geothermal option for Colgate because of the restrictions associated with the underlying
geology and the concerns held by the Village of Hamilton about drinking water
contamination. We recommend that the first installations of these shallow systems be in
the Broad Street houses. We determined this by conducting multiple cost-benefit
analyses comparing the possible economic costs of installation with the potential
economic, social, and environmental benefits. The sections that follow explain the
science behind various forms of geothermal energy and more specifically detail how and
why we reached the conclusion that geothermal energy is feasible for Colgate.
Introduction to Geothermal Energy:
In its most basic form, geothermal energy originates in the earth and flows
naturally up into the atmosphere through volcanoes, hot springs, and geysers.1 Most
naturally occurring sources of geothermal energy in the United States are located on the
1 Geothermal Energy. (2009). In Encyclopedia Britannica. Retrieved from http://search.eb.com/eb/article-9036528
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West Coast because of the amount of plate tectonic activity that forces energy up.2
However, geothermal energy can also be extracted manually by humans through shallow
or deep well systems. Humans can harness this energy and generate electricity through
the creation of power plants, or use it simply to heat and cool individual residential or
commercial buildings. Electricity generation, heating, and cooling can be accomplished
with geothermal technologies because of the temperature differential between the earth
and the air above the surface. At great depths, the earth is warmer because of the heat
energy constantly being created within the core and the radioactive decay of particles in
the crust.3 Closer to the surface, the earth remains a constant temperature because the
ground provides insulation from the air above.
One of the biggest selling points for geothermal energy is the fact that it is a
renewable, clean, domestic, and dependable source of energy. As climate change places
environmental pressures on countries across the world, and reliance on foreign oil creates
political and economic pressures on the United States and others, geothermal is becoming
a more attractive energy alternative. Geothermal energy does not rely on variable inputs
such as wind or sun as do many other renewable options. A geothermal system just
needs access to the earth's natural temperature differential and can then produce
electricity, heating, or cooling 24 hours a day, 7 days a week. Furthermore, as the price
of non-renewable energy sources such as oil and natural gas rise, geothermal energy
offers a great alternative for the U.S and Colgate, potentially alongside other more
renewable sources such as woodchips. The current technologies available to harness this
2 Blackwell, D. D., and Richards, M. 2004. Geothermal Map of North America. American Assoc. Petroleum Geologist (AAPG), 1 sheet, scale 1:6,500,000. 3 MIT-led Interdisciplinary Panel. (2006). The Future of Geothermal Energy: Impact of Enhanced Geothermal Systems (EGS) on the United States in the 21st Century. Cambridge, MA.: Tester, Jefferson et al., section 2.2.6
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temperature differential can be broken down into the two broad categories of deep and
shallow geothermal systems.4
Types of Geothermal Energy:
Shallow
Within the broad label of shallow geothermal systems there are four main types of
geoexchange systems: closed-loop horizontal, closed-loop vertical, closed-loop pond or
lake, and open-loop. Closed-loop systems consist of a network of pipes that cycle water
or a refrigerant through a closed system where nothing leaves or enters the system except
heat. The pipes can run horizontally about ten feet below the surface, vertically a few
hundred feet into the earth, or through/under a large body of water. Figures 1 through 3
depict these systems. The selection of the different types of systems (horizontal, vertical,
or pond) depends on the availability of resources such as capital, space, water,
temperatures, and bedrock type. Open-loop systems alternatively draw water from
shallow aquifers into an open-loop pipe system to extract its heat energy in a similar
fashion as closed-loop systems. Water is drawn up from wells at one end of the system
and returned back into the aquifer at the other.5
Geoexchange systems, also known as Geothermal Heat Pumps (GHPs), utilize
shallow thermal energy from the uppermost layer of the earth's crust. About ten feet
below the surface, the earth maintains a constant temperature between about 50 and 60
4 U.S. Department of Energy (2008, September). Geothermal Basics. http://www1.eere.energy.gov/geothermal/geothermal_basics.html 5 U.S. Department of Energy (2008, December). Benefits of Geothermal Heat Pump Systems. Retrieved from http://www.energysavers.gov/your_home/space_heating_cooling/index.cfm/mytopic=12660
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degrees Fahrenheit year-round.6 GHPs use this constant temperature to heat buildings in
the winter and cool them in the summer. The fluid, which is water for open-loop systems
and a refrigerant such as glycol for closed-loop systems, passes through the pipes and is
heated or cooled by the earth’s constant temperature. As this fluid moves through the
pipes inside the building, it is compressed within a heat pump to further increase or
decrease its temperature depending on the time of year. The temperature is then
exchanged directly or indirectly to a water or air medium through a heat exchanger for
distribution throughout the building. Much of the temperature gained from compression
is used to heat or cool the building, and the water or refrigerant is re-injected into the
wells at only a slightly different temperature than the ground.7 These shallow systems
are usually set up on a building by building basis because they do not have the
capabilities of deep systems to generate enough heating or cooling to run a central plant.
Figure 1: An image of a horizontal closed-loop geoexchange system. A horizontal loop needs a lot of square footage to be able to meet 100% of the heating and cooling needs of the building.8
6 U.S. Department of Energy, Geothermal Basics 7 Darby, Peter (personal communication, 9-28-09; 10-1-09); Geothermal Heat Pump Consortium. (2007). Information for Evaluating Geoexchange Applications (2nd ed). Washington, D.C. 8 Geothermal Heat Pump Consortium, Information for Evaluating Geoexchange Applications
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Figure 2: An image of a vertical closed-loop geoexchange system. A vertical system needs less square footage but must go down at least 300 feet into the ground.9
Figure 3: An image of a pond/lake closed-loop geoexchange system. Such a system requires a large enough pond or lake that has a near constant temperature year round.10
GHPs require a large initial financial investment, but generally have very low
operation and maintenance costs. Over time, these low costs will generally make GHPs
more cost effective than traditional electric, fuel, or natural gas heating systems. But the
cost and source of electricity inputs must be analyzed because GHPs can sometimes
increase electricity consumption due to their need to pump and compress water.11 While
it is not applicable to Colgate, replacing electric heating and air conditioning systems
with geothermal heating systems can actually decrease annual electricity costs. In a case
9 Ibid 10 Ibid 11 Darby, Peter (personal communication, 9-28-09; 10-1-09)
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study of the Myers family, residents of the Village of Hamilton, geothermal contractor
Peter Darby found that replacing electric base heating systems would cut their electric
consumption by nearly one third.12 The timescale over which GHPs are able to become
cost effective thus depends on various factors such as the type of GHP system, the
fluctuating cost and consumption of electricity and fossil fuels, and the already existing
heating and cooling systems.
The cost of installing geothermal systems also depends on whether the building in
question is being retrofitted with geothermal technology or if geothermal technology is
worked into the plans for a new construction project. Retrofitting is generally more
expensive, depending on the existing infrastructure, because of the cost of replacing an
existing functioning heating system. When constructing a new building, the relative cost
of installing a geothermal system is considerably less because only the differential cost
between a geothermal system and a traditional heating system must be accounted for.
Therefore the main differential between installing a geothermal system and installing a
more traditional heating system is the cost associated with drilling wells.13
Deep
Deep geothermal energy can be broken down into two separate categories, power
plants and direct-use systems. Geothermal power plants generate electricity by using
thermal energy from sources such as geysers, hot springs, or deep and extremely hot
aquifers to drive turbines. Dry steam, flash steam, and binary cycle power plants are the
12 Ibid 13 Ibid
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three types of power plants that can be constructed (see Figures 4, 5, and 6).14 Electricity
generated from geothermal power plants is an entirely renewable and reliable form of
energy, but its application depends completely on the geology of the site. Therefore the
greatest potential for these systems is located on the west coast of the U.S, where these
thermal resources are more commonly found due to high thermal gradients that allow
heat to flow or be extracted more easily to the surface.15 These high thermal gradients are
found in only approximately 10 percent of the world’s land area and require plate tectonic
activity.16
Figure 4: A dry steam power plants use the steam drawn from the earth to drive a turbine. This was the original type of geothermal power plant. 17
14 U.S. Department of Energy (2008, September). Hydrothermal Power Systems. http://www1.eere.energy.gov/geothermal/powerplants.html 15 Blackwell, D. D., and Richards, M., Geothermal Map of North America 16 László, E. (1981). Geothermal Energy: An Old Ally. Ambio, 10(5), 248-249. 17 U.S. Department of Energy, Hydrothermal Power Systems
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Figure 5: A flash steam power plant sprays fluid into deep wells which is quickly transformed into hot steam because of the extreme heat of the wells. This “flash” of steam drives a turbine. 18
Figure 6: A binary cycle power plant uses a heat exchanger to transfer the ground heat to a secondary fluid that has a lower boiling point than water. The fluid creates steam that drives the turbine, condenses, and then cycles back through a closed loop. This is similar to the shallow closed-loop systems, but on a much grander scale. 19
Direct-use hot water systems are another form of deep geothermal energy
generation but one where the technology is relatively young and still in the experimental
stages. Direct-use hot water systems take advantage of the earth’s high temperatures at
great depths just as other deep systems. Water pumped from these depths is used in
various heating and energy applications. The usable temperature ranges between about
18 Ibid 19 Ibid
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68° and 302°F.20 Generally the system consists of a deep well with a pump and an
injection system for drawing and disposing of water. The depth of this well and therefore
the feasibility of these systems depends on the geology of the area. They are ideal where
geothermal "hot spots" are present, as wells can be shallower and constructed at lower
costs.21 Direct-use hot water systems allow for other practical applications such as
heating sidewalks and roads to melt the ice or heating floors of buildings which would
allow heat to radiate up through the rest of the building because the amount of thermal
energy available to these systems is greater than the amount available to shallow systems.
History of Geothermal Use:
While European settler John Colter was the first to capture geothermal energy in
1807 with the geysers around Yellowstone, geothermal power generation was not
developed until 1904 in Italy.22 As of around the turn of the century, twenty countries
around the world use geothermal energy to generate a cumulative 8,000 megawatts of
electricity 23 The United States and the Philippines together account for about half of the
world’s generation of geothermal energy. 24 Geothermal technologies have also become
popular among colleges and universities across the country as they begin efforts to
become more sustainable and carbon neutral. 20 National Renewable Energy Laboratory (1998). Direct Use of Geothermal Energy. Washington, D.C.: Author. 21 U.S. Department of Energy (2008, March). Direct Use of Geothermal Energy. Retrieved from http://www1.eere.energy.gov/geothermal/directuse.html 22U.S. Department of Energy (2008, November). A History of Geothermal Energy in the United States. http://www1.eere.energy.gov/geothermal/history.html; Tolme, Paul (2008, September) Universities Lead the Charge to Mine the Heat Beneath our Feet. Retrieved from http://www.nwf.org/campusEcology/climateedu/geothermal.cfm 23 Brown, Lester (2003). Plan B: Rescuing a Planet under Stress and a Civilization in Trouble. New York: W.W. Norton & Co. 24 Ibid
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The Oregon Institute of Technology recently spent $6.5 million to build the first
geoplant on a college campus. The plant will generate 100% of the school’s electricity
and help make the campus more self sufficient. Oregon has the advantage of being on
the West Coast and thus having access to 300 degree water 6,000 feet below the surface,
making the construction of a deep well power plant possible. Such an endeavor would
not be possible on Colgate’s campus, but the venture still presents a noteworthy example
of a progressive initiative by a university.25 Initiatives that aim to make Colgate more
self sufficient in heating will be important steps in making the campus more carbon
neutral and more sustainable.
Hamilton College provides a much more attainable example of a college on the
East Coast that is using geothermal energy to the best of their abilities. Hamilton already
has geothermal heating and cooling capabilities in three buildings including the science
center and a large dorm and is in the process of installing a system in the Student Union.
Other East Coast and Southern schools are also testing the feasibility of relying at least
partially on geothermal energy. Bard College, another school in New York State, has
begun making engineering reports for geothermal energy on their campus on a building
by building basis.26 Southern Methodist University in Texas has begun a project to map
the "location and depth of available heat" throughout the nation by analyzing data from
deep wells already dug by oil and gas companies.27
25 Priebe, Maryruth (2009, September) Hot and Steamy: Ground-Source on Campus. Retrieved from http://www.nwf.org/campusEcology/climateedu/articleView.cfm?iArticleID=102 26 New York State Energy Research and Development Authority (2009). Energy Efficiency Measures at New College Dorm Complex. Retrieved from http://www.nyserda.org/Programs/New_Construction/Case_Studies/bardcollege.pdf 27 Tolme, Paul, Universities Lead the Charge to Mine the Heat Beneath our Feet
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Such mapping is very prevalent on the West Coast, but little is known about
geothermal resources in the Midwest, East, and South. Colgate might consider taking
part in similar geothermal mapping studies for the New York region in order to create a
more precise feasibility report in terms of temperature gradients. This could be
accomplished by an outside party or guided by a geology seminar or lab, and mapped
with the aid of the university’s GIS course. While the cost of digging the wells necessary
for such a study is substantial, collaboration with other institutions would yield very
helpful information that would aid in discovering the feasibility of geothermal systems
for specific sites.
However, at the local scale, we suggest that a completely comprehensive study
that maps the Village of Hamilton is not necessary. This paper identifies six locations
that should be considered for geothermal heating and cooling, digging an exploratory
well in one of these yards of one of these houses would allow the temperature gradient to
be discovered and could also be used later in the actual GHP system (See Table 1 for
information on the recommended locations).
Feasibility of Geothermal Energy at Colgate:
The goal of this section is to outline the current geothermal technologies available
for institutional use at Colgate in terms of the costs and benefits. Ultimately, we
conclude that geothermal heating and cooling at Colgate is most feasible in auxiliary
buildings off of the central line, and the greatest potential lies in the university-owned
houses on Broad Street. These buildings have the most potential because of the existing
fuel sources used and the potential for future renovations. While the initial costs of
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installing geothermal systems may be higher than the costs of installing traditional
heating systems, all of these buildings will become cost effective in a maximum of
twenty to forty years. Not only will the systems be cost effective, but also they will yield
social and environmental benefits. Transitioning to geothermal heating and cooling will
help make these buildings on Broad Street, currently running on fuel oil #2, more carbon
friendly, contribute to potential LEED certifications, and lower the school’s overall
carbon footprint. The geology of Colgate also allows geothermal energy to be realistic in
these auxiliary buildings on Broad Street because of their location over soft sandstone
and a confined aquifer. Finally, the success of geothermal technology at Hamilton
College shows that this technology is very feasible for Colgate.
Costs
There are high initial costs associated with installing geothermal heating and
cooling systems. These include the well digging, the materials and the construction costs
of installing pipes and the other necessary mechanical units, and the purchase of heat
pumps. Based on data obtained from Hamilton College, each well costs about $5,313 to
dig and the mechanical system (labor, piping, glycol, etc.) costs are around $29,875 per
well.28 A building requires about 1 well for every 1,300 square feet of building space.
The heat pumps themselves cost about $2,500 per ton of capacity on average.29 In the
Village of Hamilton’s climate, about 1 ton of geothermal heating/cooling capacity is
needed per 500 square feet of building.30 These averages were used to calculate the
specific costs for the individual buildings represented in the figures below. (See 28 Bellona, Steve(personal communication, 10-23-09) 29 California Energy Commission (2006). Geothermal or Ground Source Heat Pumps. Retrieved from http://www.consumerenergycenter.org/home/heating_cooling/geothermal.html 30 Darby, Peter, personal communication
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Appendix I, Table 2 for the raw data used in calculations). Many of the costs stated
above are estimated because the exact costs cannot be determined prior to the completion
of engineering reports for specific buildings as there are so many different variables
involved. While the initial cost may be higher compared to other systems with similar
capacities, geothermal systems have much lower operational and maintenance costs. One
ongoing cost that must be accounted for is the electricity the geothermal heat pumps
require to compress and distribute the liquid through the pipes.
Despite our estimation of high costs at Colgate, Hamilton College and other
universities have found that the costs of implementing a geothermal system are usually
recovered on average in six to ten years, depending on the price of fossil fuels and the
size of the initial investment.31 While our estimates suggest about a thirty year payback
time for most buildings, these calculations do not include the social and environmental
benefits of installation and assume the buildings are being retrofitted; thus the estimated
payback time may be too long. The social and environmental benefits, detailed below in
the section entitled “Valuation of Benefits,” are qualitative in nature and thus we were
unable to include them in quantitative calculations of costs. New construction also often
offers the most cost effective implementation of geothermal technology as the forgone
cost of installing a typical boiler system offsets much of the cost of the geothermal heat
pumps and the required pumping.
The following figures give a building by building cost analysis for retrofitting
Colgate's buildings currently running on fuel oil #2 with geothermal heating and cooling
systems. Cost estimates for the geothermal systems are likely overestimates, for the
reasons previously stated, and will need to be corrected after more information is 31 Bellona, Steve, personal communication
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gathered. Buildings currently heated from the central line were not considered for
geothermal in this project because it is currently more cost effective for them to stay
connected to the line. This also makes sense for the university’s environmental impact
because the central heating plant is a carbon neutral source of heat when it burns
woodchips.
Figure 7 shows the costs associated with geothermal energy for every building
owned by Colgate that currently uses fuel oil #2 for heating. This figure helps select the
buildings to consider more seriously for geothermal technologies because it clearly
displays the buildings where the cost of transitioning to geothermal will and will not be
recovered in the short term. The payback timescales for geothermal systems are
represented in Figures 8 through 12 for the buildings with the most potential.
Geologic data, as described below in the “Geology” section, further helped to
select buildings that we ultimately chose to be recommend (See Table 1 for
recommendations). The geology “up the hill” under the academic buildings and first-
year dorms is not the most conducive for geothermal because of the presence of
limestone bedrock and an unconfined aquifer. As a result, we did not seriously consider
geothermal alternatives for buildings “up the hill.”
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A Comparison of Traditional vs. Geothermal Heating and Cooling Costs per Fuel Oil #2 Building
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Figure 7: Displays the total costs for all buildings currently heated by fuel oil #2 if the current heating system were to remain (status quo) or if geothermal heating and cooling were to be installed. The geothermal prices are broken down into the initial costs (well digging, heating units, and mechanical systems) and the second year costs (just electricity).29
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A Comparison of the Total Expenditures in Ten Years for the Current Fuel Oil #2 Heating System vs. Geothermal Heating and Cooling
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Figure 8: Selected buildings that are not up the hill and have the most potential for becoming cost effective. At the ten year mark not one building is cost effective with geothermal heating and cooling.32
A Comparison of the Total Expenditures in Twenty Years for the Current Fuel Oil # 2 Heating System vs. Geothermal Heating and Cooling
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Figure 9: Selected buildings that are not up the hill and have the most potential for becoming cost effective. At the twenty year mark 88 Hamilton and 13 East Kendrick will become cost effective.33
32Colgate University, Buildings and Grounds (2009) [Campus Energy Consumption Data by Building]. Unpublished Raw Data. These calculations assume that the inflation rate of fuel prices is the same asthe appropriate discount rate, and that annual maintenance costs of geothermal systems equal the non- monetary benefits. These issues are explored further in Appendix III. 33 Ibid 17
A Comparison of the Total Expenditures in Thirty Years for the Current Fuel Oil #2 Heating System vs. Geothermal Heating and Cooling
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Figure 10: Selected buildings that are not up the hill and have the most potential for becoming cost effective. At the thirty year mark almost half of the buildings will have become cost effective.34
A Comparison of the Total Expenditures in Fourty Years for the Current Fuel Oil #2 Heating System vs. Geothermal Heating and Cooling
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Figure 11: Selected buildings that are not up the hill and have the most potential for becoming cost effective. At the forty year mark almost all of the buildings will have become cost effective.35
34 Ibid 35 Ibid
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A Comparison of the Total Expenditures in Fifty Years for the CurrentFuel Oil #2 Heating System vs. Geothermal Heating and Cooling
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Figure 12: Selected buildings that are not up the hill and have the most potential for becoming cost effective. At the fifty year mark every building except the Seven Oaks Club House, 59 Hamilton, and 68 Broad will be cost effective with geothermal heating and cooling.36
Based on the figures above and prior research, we recommend that Colgate focus
its energies on implementing GHP technologies first in houses on Broad Street running
on fuel oil #2 (see Table 1). If these projects prove successful and geothermal technology
has been established at Colgate along Broad Street, the potential for adapting the
technology to buildings on the central line could be assessed. We recommend initially
assessing Broad Street for a number of economic, environmental, and geologic reasons.
At this time, there is no convincing economic or environmental arguments to completely
ignore the central heating plant as woodchips and fuel oil #6 are inexpensive, and burning
woodchips is technically carbon neutral. Our recommendations also stem from the idea
that the power plant may be expanded soon to allow for a greater use of woodchips or
natural gas. Appendix II illustrates how geothermal technology can be evaluated in the
context of new construction projects.
36 Ibid
19
All Buildings Heated by Fuel Oil #2
Buildings with the Most Potential to Be Cost Effective*
Buildings Cost Effective with Geothermal by 30 Years
Buildings Recommended for the First Round of Geothermal Installations
49 Broad 49 Broad 49 Broad 49 Broad 68 Broad 68 Broad 80 Broad 80 Broad 70 Broad 70 Broad 92 Broad 92 Broad 80 Broad 80 Broad 94 Broad 94 Broad 84 Broad 84 Broad 116 Broad 116 Broad 92 Broad 92 Broad 118 Broad 118 Broad 94 Broad 94 Broad Preston Hill Apartments
102 Broad 102 Broad 88 Hamilton 116 Broad 116 Broad 13 East Kendrick 118 Broad 118 Broad
Chapel House Preston Hill Apartments Conant House Seven Oaks Maint Bldg
Cultural Center Seven Oaks Club House French / Italian House 59 Hamilton
Preston Hill Apartments 79 Hamilton Sanford Field House 88 Hamilton
Seven Oaks Maint Bldg 13 East Kendrick Seven Oaks Club House
Sigma Chi Watson House 59 Hamilton 79 Hamilton 88 Hamilton
13 East Kendrick Table 1: A list of all the buildings on Colgate’s campus heated with Fuel Oil #2 and our final recommendations for a focus on Broad Street (specifically the houses above) for a first round of geothermal installations. The * indicates that this decision was based on the results in Figure 7
Electricity
Electricity is the biggest unknown factor in this project. Future research must be
conducted on this topic to discover the true costs of geoexchange technology. In the
above figures the electricity costs for geothermal are considered the same as the current
electricity costs, but this is not necessarily the case as the current electricity consumption
is mainly for lighting and power rather than heating purposes. Geoexchange systems
could potentially increase the electricity consumption of Colgate as the heat pumps
require electricity for the movement and compression of liquids within pipes. We cannot
determine the exact amount of electricity required for such actions and thus the exact
20
costs associated with electricity are unknown. Testing and the first installation of a
geoexchange heating and cooling system on campus will help bring to light the true costs
and benefits.
Geology
As previously explained, deep geothermal energy and the creation of power plants
is very dependent on location. Deep geothermal wells typically harness energy at
geothermal “hot spots,” along plate boundaries where there are large amounts of tectonic
activity.37 Hamilton, NY is not located near any “hot spots” and it is therefore not
feasible to pursue deep geothermal energy on campus. Instead efforts should be put
toward the development of shallow GHPs. These geoexchange systems require wells to
be dug at depths ranging from 10 to 500 feet depending on the type of system and the
local geology. Factors such as depth of bedrock, depth of aquifers, and temperature
gradient all play a role in the required depth of the well and the cost of digging. As
knowledge of these factors, especially temperature gradients, is limited in our area, the
cost structure of GHP construction is subject to variation.
37 U.S. Department of Energy, Direct Use of Geothermal Energy
21
Figure 13: An aerial photo of the Colgate campus with buildings highlighted to show whether they are heated by the central heating plant or by fuel oil #2. The buildings in blue are not connected to the central heating line and thus hold more potential for geothermal.38
There are two main types of bedrock located under Colgate’s buildings. As seen
in Figure 14, the majority of buildings connected to the central heating plant are on top of
limestone and those buildings currently running on fuel oil #2 are over sandstone. This
geologic information allows geothermal heating and cooling to be further feasible for the
Broad Street houses recommended in Table 1 because sandstone is soft and much easier
to drill through than limestone. General data also points to the idea that bedrock is
deeper in the center of the valley because it sits below a thick layer of glacial till.
Bedrock could possibly be as deep as a hundred feet or more in some parts of the
valley.39 Exploratory wells or participation in geological surveys, like those conducted
by Southern Methodist University, would provide the information required for accurate
38 Colgate Campus Buildings by Heat Source. [computer map]. New York State GIS clearinghouse. Albany, NY. 2009. Using USGS [GIS software] 39 Selleck, Bruce, personal communication
22
analysis. Despite the lack of any wells on Colgate's campus to confirm the statements
made above about bedrock, we advocate for a shallow closed-loop vertical system.
Figure 14: The same geographic location as Figure 13; this map highlights the USGS bedrock under the buildings connected and not connected to the central line. The bedrock will affect the costs of geothermal because the harder the rock, the more costly the drilling will be. Sandstone is soft and would be easy to drill through making geothermal practical for most of the buildings not attached to the central line.40
Having an aquifer directly below many of the buildings heated by fuel oil #2
gives Colgate the opportunity to use open-loop geothermal systems. However, the
Village of Hamilton has very strict regulations over any actions that require drilling into
the aquifer because such actions could contaminate the drinking water supply.41 A
closed-loop system has less risk of contaminating aquifers and groundwater because
everything is contained within pipes. The system is also less likely to develop a blockage
in the pipes. This is a complication that can result in an open-loop system from pumping
40 Types of Bedrock Under Colgate Campus Buildings. [computer map]. New York State GIS clearinghouse. Albany, NY. 2009. Using USGS [GIS software] 41 Graham, Sean (personal communication, 12-4-09)
23
water into the pipes from the aquifer that could ultimately disrupt the functional ability of
the system.42
According to the USGS map in Figure 15, the Village of Hamilton may also have
a confined aquifer below the buildings heated by fuel oil #2, creating further incentives
for focusing efforts on these buildings. By definition, the aquifer is below the bedrock,
which may mean that it is not regulated by the Village of Hamilton.
Figure 15: The same map of the Colgate buildings as shown in Figures 13 and 14, but this time highlighting the USGS map of aquifers under Colgate. Aquifer locations will affect the costs of geothermal because of both the ease of drilling and Hamilton’s regulations.43
Another factor that contributed to our support of a vertical closed-loop system is
that it requires less surface area near the building. There is limited space in the backyards
of houses along Broad Street and even less space “up the hill” for academic buildings and
first year dorms, making a horizontal closed-loop system out the question. A horizontal
system requires an area of at least 300 feet long with a width that depends on the number
42 Bellona, Steve, personal communication 43 Aquifers Under Colgate Campus Buildings. [computer map]. New York State GIS clearinghouse. Albany, NY. 2009. Using USGS [GIS software]
24
of trenches required. A horizontal system would take up more space than Colgate has,
while a vertical system would cover a much smaller plot of land. Vertical wells require a
maximum of 20 feet between wells.44 The depth and number of wells required depend
on the amount of energy needed for each building.45 The depth the pipes reach cannot be
more than 500 feet as defined by the Village of Hamilton regulations.46 However, this is
not an issue as wells deeper than 500 feet can lead to system complications.47 Figure 16
shows that the houses along Broad Street have ample room for a vertical closed-loop
system and highlights 92 and 94 Broad in particular. 92 Broad Street would need
approximately 240 square feet for a vertical closed-loop system and 94 Broad Street will
need approximately 200 square feet for a vertical closed-loop system, both of which can
be provided in the buildings’ respective backyards.
A closed-loop pond/lake system is not an option for Broad Street houses because
Taylor Lake is not large enough or deep enough to provide constant temperatures.
44 Bellona, Steve, personal communication 45 Ibid 46 Graham, Sean, personal communication 47 Bellona, Steve, personal communication
25
Figure 16: An aerial photo of some of the houses on Broad Street to show that the backyards of these houses do have enough space for a vertical geoexchange system. The backyards’ of 92 and 94 Broad Street are highlighted to give an example of the ample dimensions. 48 Figures 13 through 16 display the complete feasibility of geoexchange heating
and cooling for the buildings not on the central line in terms of geology. The majority of
the buildings most economically feasible for geothermal are located on top of soft
sandstone that will be easy to drill through, are above a confined aquifer that may allow
the Village to be less concerned with water contamination, and have backyards large
enough to install a vertical closed-loop system. The temperature gradients located under
the fuel oil #2 buildings is unknown, so an exploratory well must be dug to decide the
depth required for the well system. If results from the exploratory well were favorable,
the well could be used as part of the geoexchange system.
48 Backyards of Broad Street Houses. [computer map]. New York State GIS clearinghouse. Albany, NY. 2009. Using USGS [GIS software]
26
Valuation of Benefits
A major deterrent for implementing geothermal technology is the high investment
cost and the long timeline for payback. However, the cost-benefit analyses represented in
Figures 7 through 12 underestimate the actual benefits. As many of the main benefits are
qualitative and many of the costs are quantitative, the costs of geothermal energy are
abundantly clear while the benefits are more uncertain and long-term. We stress that
these benefits associated with geothermal technology should be considered in the
decision making process. Considering the social and environmental qualitative benefits
as well as the financial benefits will allow for a shorter payback time and greater cost
effectiveness.
There are many methods of valuing qualitative values, though none are without
fault. Valuation systems based on surveys that attempt to quantify total willingness to
pay for reduction of carbon emissions or total willingness to accept the consequences if
no reduction occurs can be used in this case. One example is a contingent valuation
survey that asks respondents to place a value on cutting increased carbon emissions to
preserve the environment in its current state. We recommend that if quantitative benefits
are required, such surveys be administered on campus.
Financial costs aside, geothermal technology is appealing for a number of
reasons. A major factor is its contribution to abatement of carbon dioxide emissions.49
Reducing carbon emissions is appealing mainly because carbon dioxide is one of the
leading causes of climate change. If we assume that individuals value this trans-
generational environmental protection, we must account for this valuation of non-
49 U.S. Department of Energy, Benefits of Geothermal Heat Pump Systems
27
monetary environmental goods in our cost-benefit analysis. This societal benefit is
mainly nonmonetary and may not necessarily bring economic benefits to Colgate,
although we do argue this later in the section. Many stakeholders in the Colgate
community will likely value the implementation of geothermal technology based on such
values. Steve Bellona, the associate vice president for facilities and planning at Hamilton
College, believes that such values were a driving reason for their implementation of
geothermal technologies. In an interview he mentioned Hamilton College believed
geothermal technology was simply “the right thing to do.”50 Individuals in the
community will feel good about their contribution and thus value the technology.
Retrofitting buildings to geothermal heating and cooling is feasible but
geothermal is even more practical for new constructions. As the world becomes
increasingly more environmentally conscious and LEED certification standards become
widely accepted, it becomes more difficult for a non-profit institution such as Colgate to
construct a new building without obtaining a LEED certification. If Colgate decided to
make the new fitness center or any other proposed constructions LEED certified, using
geothermal energy would aid in this process (See Appendix II for a more in depth
recommendation of the implementation of a geoexchange system in the new fitness
center). A geoexchange system would make buildings much more efficient and therefore
much more eligible for LEED certification.51 Under the guidelines of LEED certification,
each building is assessed on a point system with points awarded for certain "green"
aspects such as light pollution reduction and use of recycled materials. When it comes to
energy efficiency, LEED awards up to 35 possible points. A geoexchange system has the
50 Bellona, Steve, personal communication 51 Geothermal System Qualifies University For LEED Certification. The Chief Engineer. (2007, August). Retrieved from http://www.chiefengineer.org/content/content_display.cfm/seqnumber_content/3100.htm
28
potential to receive up to 19 points for optimized energy efficiency, up to 7 points for on-
site renewable energy and 2 points for green power.
While biomass is considered a carbon neutral, renewable energy source, the
points earned by geothermal will end up being much higher than those earned from the
use of our current heating plant because of the need to use fuel oil # 6 in the winter
months to supplement woodchips. Fuel oil #6 emits large amounts of greenhouse
gases.52 By eliminating its use to heat any new buildings constructed by Colgate, we
could make the building truly carbon neutral and optimize the building's energy
performance. Furthermore, the price of woodchips could feasibly rise in the near future
due to a heightened desire of similar institutions to become more carbon neutral, making
geothermal more attractive financially.
Not only could the use of geoexchange in general have nonmonetary benefits and
aid in Colgate’s carbon neutral initiative, it could also have educational benefits. In the
face of large budget cuts, tensions may be high among faculty and staff with the
announcement of any new building constructions or renovations. Improving the
efficiency of the building in question and advertising its environmental benefits has the
potential to ameliorate this negative reaction. Furthermore, academic classes in Geology,
Geography, and Environmental Studies could take field trips to the site and learn more
about renewable energy. Space on a lobby wall could also be dedicated to explaining the
geothermal system, which could encourage increased interest about the environment and
renewable energy sources in the general student population.
52 U.S. Energy Information Administration (Date). Voluntary Reporting of Greenhouse Gases Program Fuel and Energy Source Codes and Emission Coefficients. Retrieved from http://www.eia.doe.gov/oiaf/1605/coefficients.html
29
Along the same lines, installing geothermal heating and cooling not only in new
buildings but also in buildings along Broad Street as we recommended could create great
public relations, enhancing Colgate's national reputation and appealing to prospective
students. It is likely that Colgate would see some monetary benefits in the form of
fundraising as well as nonmonetary benefits in the form of appeal of the school to
potential applicants. These are all indirect benefits that should be considered in the
decision making process for geothermal technology implementation. Installing
geothermal systems would also allow us to catch up in terms of sustainability with some
neighboring colleges such as Hamilton and Bard. The geology of Hamilton and Colgate
is very similar, thereby showing that geothermal heating and cooling could also be
successful at Colgate. There are important differences, though, between the two college
campuses, such as the potential for outside funding, the higher price for electricity at
Hamilton, and Hamilton’s use of electric heating units (see “Potential Funding” and
Hamilton College Comparison” for more information on this topic).
A Condensed List of the Potential Benefits of Geothermal at Colgate:
1) Geothermal will lower Colgate's greenhouse gas (GHG) emissions and thus our
ecological footprint will shrink. The reduction will be the result of decreased use
of fuel oils for the heating and cooling of buildings on campus.
2) Colgate will be one step closer to meeting the requirements of the Presidents'
Climate Commitment of which Colgate is a signatory.
3) Buildings will have a higher likelihood of becoming LEED certified.
4) Colgate will be better able to compete with similar collegiate institutions that are
increasingly “out greening” us. Hamilton College, just thirty minutes away,
30
already has three geothermal systems and is a competitor of Colgate when it comes
to prospective students.
5) Geothermal technology will be good public relations for Colgate as sustainability
becomes more and more important across the country and world.
6) The geoexchange systems will be a selling point for prospective students interested
in the environment and a talking point on school tours. Being “green” is very
important in today’s world, as can be seen in the sheer quantity of greenwashing
taking place. The Princeton Review suggests that more prospective students and
their parents than ever before understand climate change and are making decisions
based on these concerns.53
7) Geoexchange systems can generate nonmonetary benefits for the Colgate
community. These benefits will come as those in the community understand that
they are helping the environment. While no quantitative data is available to
confirm this point, the students at Hamilton who know about the school’s
geothermal systems do feel a sense of pride.
8) Students can become more environmentally informed and may begin to take a
more vested interest in climate change and other environmental issues. Posters
hung in buildings with geothermal heating and cooling coupled with informational
talks with trained RA’s will heighten awareness.
9) Geothermal systems can be used as an education tool for teaching sustainability. It
can be a resource that is applied to courses in various departments, such as energy-
53Princeton Review (2009).College Hopes and Worries Survey. Retrieved from http://www.princetonreview.com/uploadedFiles/Test_Preparation/Hopes_and_Worries/colleg_hopes_worries_details.pdf
31
and climate-focused First-Year Seminars as well as Geology, Geography, and
Environmental Studies courses.
10) A positive difference between geothermal and other renewable energy resources is
that geothermal systems are completely underground and not visible other than the
small pumps that can be easily contained in maintenance rooms. All the land above
the wells can still be used for other activities, although digging is not encouraged.54
Hamilton College Comparison
Hamilton College has successfully installed two geothermal heating and cooling
systems and is in the process of installing a third in its newly renovated Student Union
building. All three systems are vertical closed-loop systems with a glycol solution
running through the pipes. The first installation occurred in the atrium of their science
building over five years ago and the second system is in a newly renovated residential
house and provides 100 percent of the heating and cooling needs for the building. While
the system in the atrium of the science building was a trial run and will not become
economically practical for at least a hundred years, it allowed the college to test the
system and be sure of its effectiveness.55 Colgate must take this initial step and install
geothermal in a building on campus to at least test its practicality.
The second building that Hamilton installed geothermal heating and cooling in
was a dorm that was being renovated. The dorm has a 21,000 square foot floor plan,
sleeps 51 students, and now receives 100 percent of its heating and cooling from
geoexchange. Each room within the dorm has its own heat pump and thus residents are
54 Tolme, Paul, Universities Lead the Charge to Mine the Heat Beneath our Feet. 55 Bellona, Steve, personal communication
32
able to control their own room temperatures. This is a technology that Colgate should
explore. The entire system cost about $85,000 more than a traditional heating system
would have cost to install, although $80,000 of this cost was due to the cost of drilling 16
wells and Hamilton was able to offset much of this cost with a $48,000 subsidy from
NYSERDA. The college estimates that it will break even on the energy costs of this
building in two to three years. The success of geothermal heating and cooling in this
dorm led Hamilton to begin a similar project in their next construction endeavor, the
Student Union building.56 The achievements of geothermal heating and cooling at
Hamilton lends great credence to the idea that geothermal energy can be successful and
cost efficient here at Colgate.
Figures 17 and 18: Images of a small room on the first floor that contains the only above-ground aspects of Hamilton’s dorm’s geothermal system except for the small heat pumps in each room. Figure 17 shows the 16 well heads as they come in from the ground outside and circulate through the building. Figure 18 is of the glycol solution that circulates through the closed-loop pipe outside.
Potential Funding
Many projects that include renewable energy in renovations or new construction
can receive funding from both local and national organizations. According to Sean 56 Ibid
33
Graham, the Director of Public Works and MUC Civil Defense in the Village of
Hamilton, the Independent Energy Efficiency Projects (IEEP) offers compensation of up
to $10,000 for energy efficient projects such as geothermal systems.57 The New York
State Energy Research and Development Authority (NYSERDA) also offers incentives
for renovations and new construction that incorporate renewable energy systems.58
However, in order to be eligible for NYSERDA funding, Colgate would have to pay the
New York State System Benefits Charge.59 The school’s electricity comes from a
municipal grid as opposed to a state run grid, so it does not pay the New York State
System Benefits Charge and Colgate is ineligible for funding from NYSERDA. The
Regional Greenhouse Gas Initiative (RGGI) is an organization working to reduce
greenhouse gas emissions in the northeastern and mid-Atlantic states through Cap-and
Trade.60 RGGI is also offering incentives for decreases in carbon emissions through
decreases in electricity consumption. The American Recovery and Reinvestment Act of
2009 invested 16.8 billion dollars into energy efficiency and renewable energy. Some of
this money is being distributed through the Department of Energy as grants, with millions
of dollars available for geothermal systems.61 There are many programs that offer
funding for renewable energy projects like geothermal, although a major obstacle to
accessing these funds is electricity use.
57 Graham, Sean, personal communication 58 New York State Energy Research and Development Authority (2004). Incentives. Retrieved from http://www.nyserda.org/incentives.asp 59 New York State Energy Research and Development Authority (2004). Frequently Asked Questions. Retrieved from http://www.nyserda.org/programs/New_Construction/faqs.asp 60 Regional Greenhouse Gas Initiative. (2009) Welcome. http://www.rggi.org/home 61 U.S. Department of Energy (2008, December). Recovery and Reinvestment. Retrieved from http://www.energy.gov/recovery/renewablefunding.htm#GEOTHERMAL
34
Potential Obstacles
All research points to the idea that Colgate should pursue geothermal on campus
and should start with the houses on Broad Street recommended in Table 1. Despite the
feasibility of geothermal on Colgate’s campus, there are some potential roadblocks.
These obstacles will come in the form of the initial costs and also from the potential
regulations by the Village of Hamilton. The financial costs of implementing geothermal
energy are enumerated above, so this section will focus more on the Village’s
regulations.
The main concerns of the village, according to Sean Graham, are keeping the
drinking water safe and keeping electricity prices stable. If an open-loop system were
ever to be considered, Colgate would need to supply the town with a detailed engineering
report; a geologic survey; and a survey showing how the system would affect
landowners, groundwater, and drinking water; Colgate would also need to comply with
annual inspections of the system.62 A backflow valve would also need to be installed on
all pipes. There are no village regulations for digging or installing a closed-loop system
that does not affect groundwater. The potential problem is that groundwater is located
very close to the earth’s surface on Colgate’s campus and thus the school would have to
spend time, money, and energy to fill out forms and make sure that every precaution was
taken to protect the distribution system of the village’s potable water.
The village is also very concerned with rising electricity costs that could come
with geothermal energy use, as these systems could require higher levels of electricity
consumption. The town is allotted ten megawatt hours of hydroelectric energy per month
62 Graham, Sean, personal communication
35
at a price of one dollar per megawatt hour. When the town consumes more than this
allotment, the price jumps drastically to $7.99 per megawatt hour.63 Hydroelectric power
allows the electricity costs for the village to remain around four cents per kilowatt hour
and this could rise if geothermal energy was used.
Overall, the town does not have any regulations against geothermal. However, it
does have certain rules to protect drinking water and requires permits that need to be
obtained prior to digging.64
A Condensed List of the Potential Barriers of Geothermal at Colgate:
1) The initial costs of installing a geoexchange system and digging exploratory wells
is high.
2) Regulations from the Village of Hamilton in the form of protecting drinking water
and keeping electricity consumption down may provide some resistance.
3) Geoexchange systems have the potential to increase electricity consumption.
Next Steps:
In order for Colgate to take geothermal energy into serious consideration there are
certain steps that must be taken immediately. First and foremost Colgate must evaluate
its true commitment to sustainability and realistically define what it is working toward. If
Colgate decides to follow through with geothermal energy, a second important step will
be to hire an engineer to construct a proposal for the location and depth of the wells for
the Broad Street houses recommended in this paper. Despite our recommendations to use
63 Graham, Sean personal communication 64 Ibid
36
a close-loop vertical system, the same engineer should also determine the most effective
technologies and the exact capacity that the system will require. Determining the most
effective technologies for each location will be a pivotal decision as it will have a large
impact on the success of the system. In order for this to be determined, a test well will
need to be drilled on a proposed site for thermal response testing. This test will
determine how deep the geothermal wells will need to be as well as exactly how many
wells will need to be dug to sufficiently heat and cool the building. Once a proposal has
been written, Colgate will need to work closely with the Village of Hamilton to comply
with regulations associated with digging the wells as well as consider issues associated
with electricity consumption.
Conclusions:
The adoption of geothermal energy at Colgate is an expensive investment in the
short term. The costs to install the new technologies will be high, especially if a fully
functioning heating system exists. However, the long-term environmental, economic, and
social payback of an investment in geothermal energy is large. Cutting out the use of fuel
oil #2 will reduce greenhouse gas emissions and, therefore, Colgate’s carbon footprint.
For a large percentage of fuel oil #2 buildings and especially those on Broad Street,
geothermal will be cost effective and begin saving Colgate money within thirty years of
installation. Finally, having a geothermal system on campus will provide future
educational opportunities as well as increased environmental awareness. There are many
examples of colleges and institutions in the northeast that have invested in geoexchange
systems, and it seems that this is a logical next step for Colgate to pursue. We
37
recommend that initial systems be installed along Broad Street where the payback is
shortest and the space for wells is available.
Acknowledgements
We would like to thank Peter Darby, Thomas Myers, Steve Bellona, Sean
Graham, Bruce Selleck, John Pumilio, and Bob Turner for their help with this project.
Each served as excellent resources for data, information, and firsthand experience. The
latter two were excellent advisors to the research and writing processes. Thank you all!
38
39
Appendix I:
Location Building Sq. Ft.
Avg.Electric Use
(kwh/yr) (‘07-‘09)
Avg.Electric Costs ($/yr)
(‘07-‘09)
Avg. Cost
Fuel Oil #2 ($/yr) (‘07-‘09)
Number of
Heating Units
Required
Rounded to
Nearest Whole
Number
Total Cost of Heating Units ($)
Number of Wells
Required
Rounded to
Nearest Even
Number
Total Cost of
Wells ($)
Total Mechanical
System Costs
Current Total
Heating Cost ($/yr)
Potential First Year
Geothermal Costs ($/yr)
Potential Costs of Geothermal
Thereafter ($/yr)
49 Broad 8344.00 28425.00 1279.13 12835.07 16.69 17.00 42500.00 6.42 8.00 42496.00 239000.00 14114.20 325275.13 1279.13
68 Broad 13050.00 85280.00 3837.60 6760.42 26.10 27.00 13500.00 10.04 12.00 63744.00 358500.00 10598.02 439581.60 3837.60
70 Broad 6244.00 22870.00 1029.15 6213.09 12.49 13.00 32500.00 4.80 6.00 31872.00 179250.00 7242.24 244651.15 1029.15
80 Broad 8770.00 93930.00 4226.85 12875.18 17.54 18.00 45000.00 6.75 8.00 42496.00 239000.00 17102.03 330722.85 4226.85
84 Broad 19000.00 84780.00 3815.10 16447.55 32.90 33.00 82500.00 14.62 16.00 84992.00 478000.00 20262.65 649307.10 3815.10
92 Broad 13698.00 58660.00 2639.70 24116.75 48.23 49.00 122500.00 10.54 12.00 63744.00 358500.00 26756.45 547383.70 2639.70
94 Broad 10830.00 69729.00 69729.00 16498.46 21.66 22.00 55000.00 8.33 10.00 53120.00 298750.00 19636.27 410007.81 1045.94
102 Broad 6722.00 49166.00 2212.47 6872.50 13.44 14.00 35000.00 5.17 6.00 31872.00 179250.00 9084.97 248334.47 2212.47
116 Broad 4700.00 17940.00 807.30 5326.86 9.40 10.00 25000.00 3.62 4.00 21248.00 119500.00 5326.86 165748.00 807.30
118 Broad 8770.00 93930.00 4226.85 12875.18 17.54 18.00 45000.00 6.75 8.00 42496.00 239000.00 17102.03 330722.85 4226.85 Chapel House 10830.00 69729.00 3137.81 16498.46 21.66 22.00 55000.00 8.33 10.00 53120.00 298750.00 19636.27 410007.81 3137.81
Conant House 5483.00 52475.00 2361.38 4164.53 10.97 11.00 27500.00 4.22 6.00 31872.00 179250.00 6525.91 240983.38 2361.38
Cultural Center 5617.00 57040.00 2512.80 8961.99 11.23 12.00 30000.00 4.32 6.00 31872.00 179250.00 11474.79 243634.80 2512.80
French / Italian House
4100.00 25625.00 1153.13 5472.08 8.20 10.00 25000.00 3.15 4.00 21248.00 119500.00 6625.21 166901.13 1153.13
Preston Hill
Apartments 5040.00 16967.00 763.52 6845.48 10.08 10.00 25000.00 3.88 4.00 21248.00 119500.00 7608.99 166511.52 763.52
Sanford Field House 67000.00 67000.00 3015.00 34445.27 134.00 134.00 335000.00 51.54 52.00 276224.00 1553500.00 37460.27 2167739.00 3015.00
Seven Oaks Club House 6835.00 157600.00 7092.00 3671.85 7.34 8.00 20000.00 5.26 6.00 31872.00 179250.00 10763.85 238214.00 7092.00
Seven Oaks Maint Bldg 1476.00 19135.00 861.08 2325.80 2.95 4.00 10000.00 1.14 2.00 10624.00 59750.00 3186.88 81235.08 861.08
Sigma Chi 13886.00 139232.99 6265.48 22564.72 27.77 28.00 70000.00 10.68 12.00 63744.00 358500.00 28830.20 498509.48 6265.48 Watson House 5518.00 20000.00 900.00 5565.53 11.04 12.00 30000.00 4.24 6.00 31872.00 179250.00 6465.53 242022.00 900.00
79 Hamilton 2783.00 11926.84 536.71 3598.70 7.20 8.00 20000.00 2.14 4.00 21248.00 119500.00 4135.41 161284.71 536.71
59 Hamilton 8375.00 11945.00 537.53 5304.60 10.61 11.00 27500.00 6.44 8.00 42496.00 239000.00 5842.13 309533.53 537.53
88 Hamilton 2545.00 55030.00 2476.35 5628.41 5.09 6.00 15000.00 1.96 2.00 10624.00 59750.00 8104.76 87850.35 2476.35
13 East Kendrick 4507.00 17440.00 784.80 8385.01 9.01 10.00 5000.00 3.47 4.00 21248.00 119500.00 9169.81 146532.80 784.80
Table 2 displays the costs for heating and cooling all buildings on campus currently using fuel oil #2 and the potential costs if those were retrofitted for geothermal heating and cooling instead. The square footage, average electricity use, and average costs for fuel oil #2 were all collected from Colgate’s Buildings and Grounds. Current fossil fuel prices are assumed to continue indefinitely. The cost of electricity was created by multiplying the consumption (in kWh) by .045 because the average cost of electricity in Hamilton is around 4 cents. The numbers of heat pumps, wells, and other mechanicals supplies as well as their respective costs were calculated based on numbers used by Hamilton College. For every 500 sq ft of building, one ton of heating capacity is required (you can get heat pumps in the one ton variety and place them in each room or have bigger pumps with heat ducts) and each ton of heating capacity costs around $2,500. For every 1,300 sq ft of building, one well is required and when this is calculated it must be rounded up to the nearest even number because for every well that goes down another must come up. This means that each building will have more capacity to heat then necessary. For each well, the digging costs around $5,312 but this will be very dependent on the location. Finally the mechanical costs of the system, including piping, the glycol solution, labor, etc., will cost about $29,875 per well.
Appendix II:
Recommendation for the Implementation of a Geoexchange System in the Fitness Center Construction Project
(Edited version of the document presented to Lyle Roelofs, Interim President of Colgate
University, on November 20, 2009)
In its most basic form, geothermal energy is energy that originates in the earth and
flows naturally up into the atmosphere. Natural sources of geothermal energy include
volcanoes, hot springs, and geysers. Most naturally occurring sources of geothermal
energy in the United States are located on the west coast because of the amount of plate
tectonic activity that is required to force geothermal energy to the surface. Technology
has also allowed humans to extract this energy through shallow or deep well systems.
Humans can use high temperature geothermal resources to generate power or directly
heat buildings or we can capitalize on the temperature differential between the subsurface
and the air to heat or cool buildings using heat exchange technology. At depth the earth is
warmer because heat energy is created within the core as radioactive particles in rocks
40
constantly decay. Closer to the surface, the aquifers and the earth are at a constant
temperature that does not vary seasonally because it is heated by radiation from the
earth’s core but is insulated from above surface temperature variations.
Geothermal heat exchange technology currently exists that allows us to use this
natural difference to our advantage. As global climate change increases environmental
pressures across the world, and reliance on foreign oil continues to place political and
economic pressures on the United States and other western countries, geothermal
solutions are becoming more attractive energy alternatives. As a clean, renewable,
reliable, and domestic source of energy, there is great potential for the use of geothermal
energy across the United States, but also at Colgate University.
Installing geothermal heating and cooling capabilities in the newly planned fitness
center could be a great step toward creating a greener Colgate. As signatory to the
American College and University Presidents' Climate Commitment (ACUPCC), Colgate
has committed itself to carbon neutrality and geothermal heating and cooling could aid in
this attempt. Geothermal heating and cooling would also be a huge advantage if the goal
of the fitness center were to attain LEED certification. The alternative plan would be to
connect the new fitness center to the central heating plant, which is powered by
woodchips. While this source is technically considered carbon neutral, the validity of the
plant's neutrality is questionable. When the temperature drops below 35-40 degrees the
plant must supplement heating with fuel oil # 6. This temperature threshold, already well
within normal temperature ranges for central New York, would almost certainly raise if
the fitness center were added to the system as prior to construction of the Ho Science
Center the temperature threshold was as low as 30 degrees. Furthermore, through basic
41
economics, we can expect prices for woodchips to rise as becoming "green" becomes
more popular in central New York. As the central plant already accepts up to 33 tons of
woodchips per day, this cost could be significant.
As the world becomes increasingly environmentally conscious and with the wide
acceptance of LEED certification standards, it becomes more difficult for a non-profit
institution such as Colgate to construct a new building without getting it LEED certified.
If Colgate decided to make the fitness center LEED certified, using geothermal energy
would aid this process. A geothermal heat exchange system would make the building
much more efficient and therefore much more eligible for LEED certification. The way
LEED certification works, each building is assessed on a point system with points
awarded for certain "green" aspects such as light pollution reduction and use of recycled
materials. When it comes to energy efficiency, LEED awards up to 35 possible points. A
geothermal heat exchange system has the potential to receive up to 19 points for
optimized energy efficiency, up to 7 points for on-site renewable energy, and 2 points for
green power. Biomass is considered a carbon neutral, renewable energy source, however
in the end the points earned by geothermal will end up being much higher than those
earned from the utilization of our current heating plant because of the need to use fuel oil
# 6 in the winter months to supplement the woodchips. Fuel oil #6 emits large amounts of
greenhouse gases. By eliminating its use to heat the new fitness center we could make the
building truly carbon neutral and optimize the building's energy performance.
Not only could the use of geothermal in general, and specifically with the fitness
center, aid in Colgate’s carbon neutral initiative, it could also have nonmonetary benefits
including educational benefits. In the face of large budget cuts, tensions may be high
42
among faculty and staff with the announcement of a new fitness center. Improving the
efficiency of the building and advertising its environmental benefits has the potential to
improve this reaction. Furthermore, academic classes in the geology and geography
departments could take field trips to the site and learn more about renewable energy.
Space on a wall in the lobby could also be dedicated to explaining the geothermal system,
which could encourage increased interest about the environment and renewable energy
sources in the general student population.
Along the same lines, installing geothermal heating and cooling in the fitness
center could be good for Colgate's national reputation and appeal to prospective students.
It would also allow us to catch up in terms of sustainability with some neighboring
colleges such as Hamilton. Hamilton College currently has geothermal heating and
cooling in two buildings and is installing a third system in its newly renovated student
center. The first installation occurred in the atrium of their science building and the
second system is in a residential house and provides 100 percent of the heating and
cooling for the building. The geology of the two schools is very similar, thereby showing
that geothermal heating and cooling could also work at Colgate. While the system in the
atrium of their science building was a trial run and will not become economically
practicable for at least a hundred years, it allowed them to test the system and be sure of
its effectiveness. We recommend that Colgate make a similar decision for the fitness
center. While it may not be economically viable in the short run, because of its proposed
location near the heating plant, it would be a great trial run of the technology at Colgate.
Estimates show that a geothermal heat exchange system would require a
significant upfront investment of about $100,000 more than the cost of connecting the
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building to the central heating plant (see table 3). The cost of internal piping and
ventilation infrastructure will be comparable to the alternative. If the system is
implemented correctly we can expect reduced annual energy costs to pay back this initial
investment.
Heating Unit Prices Well System Prices Total Additional Cost
Geothermal Heating and Cooling $50,000 $42,496 $92, 496
Table 3: The cost of geothermal heating and cooling in the proposed fitness center. The price for heating units and the well system were estimated using the proposed heatable square footage and the costs for materials at Hamilton per square foot. To potentially make the new fitness center more economically efficient with geothermal heating and cooling, we recommend the use of lower ceilings to reduce the area that requires heating.
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Appendix III: The calculations shown in Figures 8 and 9 of the paper are based on simplifying
assumptions that this appendix explores further by taking more carefully into account
four factors: rising fuel prices, financing costs, future operating costs, and nonmonetary
benefits. Taking account of each of these factors requires making an assumption about an
uncertain future, so this appendix presents alternative scenarios.
If fuel prices rise at annual percentage rate p (measured in decimals), then an
annual fuel expenditure of $E would in t years rise to $E(1+p)t, so for example if fuel
prices rise 5% per year then 10 years from now the annual fuel expenditures at 92 Broad
would be $24,000(1.05)10 = $39,100. Once an annual percentage rate is chosen for future
fuel price increases, it’s straightforward to compute the series of future fuel expenditures
(assuming no change in behavior—such as energy conservation—or external forces such
as weather).
Accounting for financing costs is a little more complicated. If funds to pay the
initial costs of installing geothermal systems are borrowed, the financing costs in a
particular future year depend on the interest rate, the amount borrowed, how many years
have gone by, and the term of the loan (how fast the principal has to be repaid). One way
to simplify the analysis is to compute the present discounted value (PDV) of future (net)
benefits of geothermal and compare that PDV to the initial investment costs. The PDV of
a benefit of $X sometime in the future is the amount that would have to be set aside (and
invested) now so that it would accumulate in the future to just equal $X. Because the
investment would earn (compound) interest, the PDV of $X in the future is less than $X
by an amount that depends on the interest rate and how far in the future the benefit of $X
would be received. If the annual interest rate (assumed for convenience to be constant) is
45
i then a benefit of $X t years in the future has a PDV of $X/(1+i)t. For example, in order
to finance the future fuel costs of $39,100 10 years from now, if the interest rate is 5%
then $39,100/(1.05)10 = $24,000 would need to be invested. The interest rate used in the
calculation of a PDV is sometimes called the discount rate and 1/(1+i)t is called the
discount factor since when multiplied by any future (net) benefit it yields the PDV. The
appropriate discount rate is one that measures the opportunity cost of using Colgate funds
to invest in geothermal instead of using the funds for something else. Reasonable
candidates for the appropriate discount rate include the interest rate Colgate would have
to pay to borrow funds externally, the rate of return on Colgate’s endowment, and the rate
of increase of student charges. Once a discount rate is chosen, by calculating the PDV of
each future year’s fuel expenditure savings and then summing them the PDV of the
benefits of geothermal can be calculated and compared to geothermal’s initial investment
costs.
Taking account of both rising fuel prices and the opportunity costs of using funds
for geothermal instead of something else, the PDV of future fuel expenditure savings due
to investment in geothermal can be calculated as ( )T
t t
t=1
$E 1 p / (1 )i+ +∑ where T is the
number of years that fuel savings will be realized (that is, the useful life of the
geothermal system). This formula can be simplified, however, since ( ) is
very closely approximated by (
t t1 p / (1 )i+ +
)t1 p i+ − . Therefore instead of making separate
assumptions about fuel price inflation and the discount rate, the relevant calculation can
be made with a single assumption about the difference between the two. This makes
46
modeling much easier and also points out that the calculations used in the body of the text
are correct if the discount rate equals the rate of increase of fuel prices.
A spreadsheet is available1 that computes the cumulative PDV of fuel price
savings for each Colgate building studied in this project, using a range of assumptions
about the difference between the fuel price inflation rate and the discount rate. For
example, if fuel prices rise at a rate that is 3 percentage points higher than the discount
rate, the payback period for 92 Broad Street is 18 years; if fuel prices rise at a rate that is
only 1 percentage point higher than the discount rate, the payback period is 21 years. The
following table presents selected payback period calculations; full details are available in
the spreadsheet. The 0% column corresponds to the calculations in Tables 8 and 9.
Table III.1 Payback periods (years) for geothermal investing
Difference between fuel price inflation rate and discount rate (p – i)
Building -1% 0% 1% 3%
68 Broad >100 66 50 36
92 Broad 26 23 21 18
94 Broad 29 25 23 19
118 Broad 30 26 23 19
Sigma Chi 26 23 20 17
88 Hamilton 18 16 15 13
13 East Kendrick 20 18 17 14
1 http://www.colgate.edu/academics/departments/environmentalstudies/studentresearch.html; the spreadsheet can also be obtained from Professor Robert W. Turner at [email protected] .
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One of the uncertainties about investing in geothermal systems at Colgate is that
the systems will require more electricity use (mainly for pumps), but it’s unknown how
much more. Obviously, the higher are those future operating costs, the less worthwhile is
the investment in geothermal. If the future operating costs were known, or if Colgate was
comfortable making an assumption about their size, it would be easy to incorporate them
into the analysis: the benefits of future reductions in heating fuel expenditures would be
reduced by the amount of new spending on electricity. Modeling of benefits and costs
could also include assumptions about the rate at which electricity costs would rise
through time, which would probably be different than the rate at which heating fuel costs
will rise.
As discussed in the body of this report, investing in geothermal is likely to yield
several nonmonetary benefits: the good feelings generated by reducing Colgate’s carbon
emissions, educational benefits, and positive public relations and reputation effects,
which might among other things help in Colgate’s recruitment and admissions efforts.
While at least some of these benefits might be in principle measured in monetary terms,
their size is unknown. As with operating costs, if the size of these benefits were known or
if Colgate was comfortable making an assumption about their magnitude, it would be
easy to incorporate them into our analysis. They would simply be added to the future fuel
price savings in computing the benefits of investing in geothermal. Assumptions could
also be made about whether these benefits grow over time and, if so, at what rate.
As a starting point for incorporating operating costs and nonmonetary benefits
into the analysis, we point out that if the two exactly offset each other, the previous
analysis is accurate. So, for example, Figures 8 and 9 and Table III.1 are accurate if
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future operating costs just equal the future nonmonetary benefits. We can also recalculate
payback periods based on different assumptions about the relative magnitudes of the
future nonmonetary benefits and operating costs. We do so in two ways: Tables III.2 and
III.3 recalculate the payback periods shown in Table III.1 based on annual nonmonetary
benefits being, respectively, $5000 and $40,000 more than annual operating costs. Table
III.4 shows how large the annual difference between nonmonetary benefits and operating
costs would have to be to make the payback period for each building equal 15 years;
these can be compared other possible expenditures by Colgate, for example the cost of
providing full financial aid to one more student. The spreadsheet referenced earlier
provides the details behind these tables and allows other scenarios to be investigated.
Table III.2 Payback periods (years) for geothermal investing
if annual nonmonetary benefits exceed annual operating costs by $5000 Difference between fuel price inflation
rate and discount rate (p – i)
Building -1% 0% 1% 3%
68 Broad 42 38 34 29
92 Broad 21 19 18 16
94 Broad 21 20 18 16
118 Broad 20 18 17 15
Sigma Chi 20 19 17 15
88 Hamilton 9 9 9 8
13 East Kendrick 12 11 11 10
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Table III.3 Payback periods (years) for geothermal investing
if annual nonmonetary benefits exceed annual operating costs by $40,000 Difference between fuel price inflation
rate and discount rate (p – i)
Building -1% 0% 1% 3%
68 Broad 10 10 10 10
92 Broad 9 9 9 9
94 Broad 8 8 8 7
118 Broad 7 7 6 6
Sigma Chi 9 8 8 8
88 Hamilton 2 2 2 2
13 East Kendrick 4 4 4 3
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Table III.4 Amount by which annual nonmonetary benefits have to exceed annual operating costs in order for a 15-year payback period
Difference between fuel price inflation rate and discount rate (p – i)
Building -1% 0% 1% 3%
68 Broad $23,061 $22,545 $21,978 $20,672
92 Broad $14,218 $12,376 $10,353 $5,692
94 Broad $12,096 $10,835 $9,452 $6,263
118 Broad $9,426 $8,315 $7,087 $4,228
Sigma Chi $12,393 $10,669 $8,777 $4,416
88 Hamilton $658 $228 ($244) ($1,332)
13 East Kendrick $2,024 $1,384 $681 ($940)
Note: numbers in parentheses indicate that the payback period would be 15 years even if annual operating costs exceeded nonmonetary benefits by that amount.
51
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