A Case Study: Solar Panels at Boston College
Annie Meyer 1, 2014
Farhin Zaman
Elizabeth Norton
GE 580 Environmental Studies Senior Seminar
Boston College
Chestnut Hill, MA April Introduction
Solar Photovoltaic: Background
Solar cells and photovoltaics were first invented in 1954 after a lot of research around photoelectric technologies and beginning to use the sun’s energy for other purposes (“Timeline…”). Now, solar has been around for many decades, and has been proved to consistently work well. Like most other technology, solar has improved immensely over time, gaining more efficiency and becoming a more viable option for homes and businesses. When it was first invented, each cell had a 6% efficiency rate (“Timeline…”). Currently most cells have an efficiency rate of approximately 25% though there are cells being developed with over 40% efficiency (“Stacking the Deck” 2014). That is truly an amazing transformation, and a testament to technology. Solar PV can be difficult to understand, especially when you are thinking about using it for your home or business. There is a long list of things to consider, but the first step is to understand the basic technology behind the panels. Solar panels contain solar cells (mentioned above) that collect heat energy from the sun. Once this energy is trapped, an inverter is used to convert the energy so that it is usable within your home to power things with electricity (EnergySage). Though you may not be able to produce enough energy to meet 100% of the needs for your home, solar PV can still help you save a lot of money. Solar PV is considered ‘clean’ energy because it harnesses energy from a renewable resource: the sun. Our planet is constantly receiving energy from the sun, so why not utilize it? Overall solar is a very environmentally friendly solution in a society that uses colossal amounts of energy. Solar at other Colleges/Universities: Brandeis, Harvard, and Stonehill
By looking at the solar installations at other colleges and universities, we were
able to get solid and successful examples of solar working in different ways at places
similar to BC.
Harvard has solar panel systems on eight of its buildings, the largest of which
produces 590,000 kWh/year. The university also purchases renewable energy from offsite
sources and has a wind turbine mounted on one of its buildings. Combined, 17% of their
electricity comes from renewable sources, while saving them money on the use of fuel
and utilities (“Sustainability…” 2013). Harvard is clearly making a statement about being
green and moving towards cleaner technologies. While we understand that BC hopes to
do the same, the university is also working on a ten year plan to add housing and new
facilities. Taking on one solar project is much more reasonable at the moment.
Stonehill College is currently building one of the nation’s largest college campus
solar fields. It is a 2.7 megawatt field that will contain 9,000 solar panels. The solar field
is expected to save about $185,000 a year on energy costs and account for 20% of the
campus’ electrical usage (“One of Nation’s…” 2014). This array produces such a large
portion of the college’s energy mostly because Stonehill is only a quarter of the size of
BC, making it’s energy use much smaller (“Stonehill College” 2014). In addition, field
arrays have to be built away from the campus, making the use of solar less noticeable.
While we do not propose making solar extremely visible at BC, we think that it is
important that students can physically identify the connection between the panels and
energy use.
Brandeis installed solar on the roofs of two buildings in 2010. At the time, the
project was one of the largest in the state, and these panels currently produce 10% of the
annual energy needed at their sports center (“Campus Sustainability Initiative”).This plan
is what we think should be the closest to our proposed project at Boston College. This
type of system offers energy savings and becomes iconic to the university. This is a good
place to start, and hopefully, if BC falls in love with solar, the administration would then
add more.
Solar at Boston College
Implementing solar panels on Boston College’s campus is an effective and easy
way to introduce clean energy with proven technology. Solar panels offer both an
environmental and economic benefit, especially at universities where energy
consumption is high. With an undergraduate population of over 9,000 students, 2 major
stadiums, 3 major dining locations, and over 20 dormitories, Boston College is always
using large amounts of energy. Our report will outline the thorough investigation of four
different buildings on campus, and what a Solar PV system offers in each situation. The
findings will compare third party ownership with private ownership, giving a
comprehensive plan for Boston College moving forward. Solar PV will help reduce BC’s
electricity bills, protect against rising energy costs, and increase sustainability initiatives.
Our primary objective is to create a realistic plan for the first implementation of solar
panels on campus with the hope that the B.C. administration will accept the idea.
Methods
Picking the location
Over the course of this project our team used process of elimination to determine the best location for a solar PV system on Boston College properties. Through meetings with two of our mentors -­‐ John MacDonald the BC Energy Manager, and Bob Pion the BC Sustainability Director -­‐ we were given advice on how to decide which locations would be feasible and most beneficial to the school. We examined the multitude of buildings that Boston College maintains on several properties -­‐ Main campus, Newton campus, Brighton campus, and the Weston Observatory. From these options, building choices were narrowed down based on a series of criteria, an overview of which can be seen in Figure 1. The basic variables involved were aesthetics, BC’s ten year plan, and annual energy use. Figure 1: Flow chart outlining the process of elimination for solar system locations.
The initial proposal of this project was to implement solar panels on the roof of the Commonwealth Ave Parking garage. We ruled this option out due to aesthetics. Its proximity to St. Mary’s means that the Jesuit residents would directly overlook the panels on top of the garage. We ruled out all of middle campus because it consists of buildings with gothic architecture, which is the aesthetic that the BC administration is most dedicated to in regards to the campus’ appearance. This group includes buildings such as Devlin, Lyons, Gasson, Fulton, and Stokes Hall. It also includes buildings in close proximity to gothic architecture, like McGuinn, as well as buildings in view of middle campus, such as Conte Forum (the roof of which is also taken up mostly by skylights, leaving little area left for solar panels). Next, our team was shown the 10-­‐year construction plan for Boston College’s campus which revealed several buildings and structures that will be knocked down in the near future, including Edmond’s Hall and Carney. Our team decided not to propose installing solar panels on any buildings that will be built in the near future, such as the new Plex athletic building, because the construction plans for them are not yet fully concrete and we want this proposal to be applicable in real time. A couple of buildings, like the Brighton Campus Dance Studio building, were removed from our list because they are simply too small to hold a valuable number of solar panels. The remaining buildings were reviewed based on their year-­‐round energy use. Buildings that are not used throughout the entire year (i.e. not used very much during the summer) were also eliminated since solar panels are most efficient and useful in places where energy is used all the time. This group included all dormitories, including all those on Newton Campus, upper Main campus, and lower Main campus.
All of main campus runs on one energy meter, which makes it more difficult to involve another type of energy generating system on one of the main campus buildings. The energy offset from the panels would come out of the campus’ total energy use rather than out of just the energy use of the building it is installed on. Though it would be possible to have the system in place on a single building while having it hooked up to the school’s net metering system, our team agreed that since we are proposing installing solar panels at Boston College for the first time, it would be best to make this a contained system on a single building. This way the administration can look at the project and decide how to move forward. This process of elimination narrowed down our choices to four locations -­‐ Cadigan Alumni Center (Figure 2a), 129 Lake Street (Figure 2b), the Beacon Street Garage (Figure 2c), and St. Clement’s Hall, the campus data center (Figure 2d). All four of these buildings we have flat roof tops, which means that solar panels could be set at the proper angle and direction for best possible production. The Beacon St Garage is large, which would allow it to accommodate a very large solar panel system. Unfortunately, it has parking spots on its roof, so a canopy structure would have to be built to accommodate the panels. This is a fairly standard procedure but it can be costly. Though we did not calculate the expense of building these solar canopies on top of the garage, it would be an added expense on top of the cost of buying and installing a system at this location. Unlike the Beacon Street Garage (and all buildings on main campus for that matter), the three other buildings, all on Brighton Campus, run on their own individual meters. This would make it easy for the solar panel system to directly offset the energy use of the building on which it is installed.
Figure 2: Aerial views of the four buildings that were considered as the location for a solar panel system, with roof areas mapped out in blue (a. Cadigan Alumni center, b. 129 Lake Street, c. Beacon Street Garage, and d. St. Clement’s Hall).
Financial Analysis
a. Building and System Estimates
At this point in the process we began a financial analysis of a potential system on each of the four buildings. This was made possible by the information provided to us by John MacDonald. The estimate involved finding the system size (in kilowatts per hour -­‐kWh) that would be able to fit on the roof of the building in question, as well as the cost of purchasing that sized system. In order to get the most well-­‐rounded estimate possible our team employed three different sources for these calculations. After finding three different values, we took an average to obtain the most accurate numbers. The first source was our team’s own calculations. We used the tools on Google Earth to measure out the roof area of the four buildings. We then deduced how many panels would be able to fit on that sized roof by dividing the area by the size of a standard sized solar panel, which is 19.5 square ft (“Timeline…”). Since a standard sized panel produces 250 watts per hour, we multiplied the number of panels by 0.25 kilowatts per hour to calculate the system size in kWh (Aggarwal, 2014). These types of systems generally cost $2.50 per watt, so in order to calculate the cost of purchasing the panels, we multiplied the system size by the price for kWh ($2,500). The error involved in this calculation is the fact that solar panels are often tilted meaning that the roof may fit more or less than the exact number that fit inside the initial roof area. The second source was the solar energy calculator on the PV Watts website. Using their program, we again mapped out the roof area of each building, and were provided with the system size in kWh. We then calculated the cost using the given system size, using the method mentioned previously. When using this method, tracing the building area was difficult. We could not be sure that the area we traced was the viable area on each building. The last source was a website called Energysage. On their program we selected each building on a map by pinning the roof and were provided with an estimate of cost and savings. Personnel at the company were kind enough to give us the system size they calculated using their own tools. Because you pin the building on EnergySage, it is hard to tell whether it will calculate the right parts of the roof. For example, Cadigan Alumni Center has skylights that we did not want included as part of the panel area. Since the three sources we used had some measure of error involved, we took the average of all three in order to provide the BC administration with the best estimate possible. Additionally, while the two websites take into consideration several factors that we were not able to -­‐ such as factoring in the amount of shading on each roof as well as accounting for the tilt of the panels when placed on the roof -­‐ they have their faults. These programs spat out numbers without us being able to see their calculations, and as mentioned above, we had different concerns with each. We took an average system size from our three estimates to see how much energy a system on each of these roofs would produce and how much of that building’s energy use would be able to be offset by that particular system size. b. Pro forma Calculations
Our mentors at the green energy company First Wind gave us a pro forma model for excel. This model provided us with a basic outline of how much energy a solar system could possibly produce on main campus and the potential savings for BC. We wanted to compare the costs and savings between private (BC) ownership and 3rd party ownership of the system in order to deduce the most financially sound conclusion. In order to come to this conclusion we had to tailor the pro forma by creating four different proformas -­‐ one for each of the four final buildings. We input data we received from the Boston College energy manager, John MacDonald, in order to calculate the financial aspects of installing solar panel systems on each of the four buildings. This analysis was based on the buildings’ annual energy uses, annual energy costs, and the campus energy rates from NSTAR. Results
Building and System Estimates
Table 1: The annual electrical use and bill for each building chosen. Annual electrical use (kWh)
Annual Bill
Cadigan Alumni Center
528,538
$71,881.17
129 Lake St.
261,544
$35,569.98
Beacon St. Garage
1,576,800
$214,444.80
St. Clements Hall
4,091,784
$556,482.62
Table 2: The number of panels, the size of those panels in kWh, and the net cost of that system as calculated from the area by using aerial shots of each building on Google Earth.
Net Cost of Panels
Our Our Area
Sq. Ft
# of System size ($2.50 per Calculations
(sq. ft)
per Panel
Panels
(kWh)
panel)
Center
12,432
19.25
646
161.5
$403,750.00
129 Lake St.
20,785
19.25
1080
270
$675,000.00
39,406
19.25
2047
511.75
$1,279,375.00
17,965
19.25
933
233.25
$583,125.00
Cadigan Alumni Beacon St. Garage
St. Clements Hall
Table 3: The number of panels, the size of those panels in kWh, and the net cost of that system as calculated by the PV Watts website energy system calculator. PV Watts # of System size Calculations
Panels
(kWh)
Net Cost of Panels
Center
713
178.2
$445,500.00
129 Lake St.
1016
254.4
$636,000.00
Beacon St. Garage
2680
670
$1,675,000.00
St. Clements Hall
800
200
$500,000.00
Cadigan Alumni Table 4: The number of panels, the size of those panels in kWh, and the net cost of that system as calculated by the Energy Sage website instant solar estimator. System Energy Sage # of size Net cost of system
Calculations
Panels
(kWh)
($2.50 per panel)
473.6
118.4
$296,000
129 Lake St.
642.94
160.74
$401,850
Beacon St. Garage
3876.2
969.05
$2,422,625
St. Clements Hall
666.164
166.54
$416,350
Cadigan Alumni Center
Table 5: List of the system sizes of each of the four buildings in kWh, averaged from the results listed in Tables 2, 3, and 4, along with the cost of that averaged system size. Cost Average System size (kWh) (private ownership)
Cadigan Alumni 152.7
$381,750.00
129 Lake St.
228.4
$571,000.00
Beacon St. Garage
625.9
$1,564,750.00
St. Clements Hall
200
$500,000.00
Center
Pro forma Calculations
The financial costs and benefits are a major part of whether an institution, like BC, would consider implementing solar panels and the type of system that would be used. An important tool in our analysis was the use of pro forma financial statements, which present the anticipated results of a certain project/ transaction. In our case, Matt Marino from First Wind, provided a pro forma model that outlined the 3rd party ownership of the solar system through a Power Purchase Agreement (PPA). In a PPA, BC would have to pay a discounted rate per kWh for the energy produced by the solar panels. In our case, a solar company, like First Wind, would charge BC $0.12 per kWh for the energy produced by the solar system, which is a lower rate than $0.136 per kWh that is currently charged by NSTAR. First Wind would charge BC for the energy produced by the solar panels at a reduced rate and then BC would pay for the rest of their electrical needs through NSTAR. As a result, BC’s annual energy bill would be lower from their average annual bill with NSTAR. The pro forma outlines the costs and savings in Tables 6-­‐9 for the respective buildings in our study. For example, in Table 6, the pro forma model for Cadigan Alumni Center uses the building’s annual electrical usage and utility bill that were calculated in Table 1. From there, we used the average system size, calculated in Table 5, to estimate the energy production of the panels and the amount BC would save. We did not calculate the costs of the solar PV system under 3rd party leasing because BC would not be responsible for the installation and maintenance costs under this system. In Table 6, the estimated solar project size (1 MW) and percentage of energy production provided for BC (15%) was given to us by First Wind. To calculate the amount of energy produced by the solar system for Cadigan, we took 15% of the amount of energy produced annually, which would be 79280.7 kWh annual solar energy produced and BC would pay a discounted rate for that energy. The energy bill for Cadigan would save $10,782.18 on it’s usual bill. Cadigan’s current bill, calculated in Table 1, is $71,881.17 per year, but with the solar system, the new bill would be $61,098.99. If this value is carried throughout the life of the solar system, which is around 20 years, then BC would save $25,369.82 in that amount of time for just one building. If BC decided to purchase the solar panels and own the system and reap benefits like Solar Renewable Energy Credits (SRECS), then the financial projections are a bit different. Unlike the 3rd party leasing system, BC would have to pay significant upfront costs for the installation of the panels. In the same example from Table 6 of Cadigan Center, we used our estimate of the solar system size (152.7 kWh) that BC could install on the roof of the building. From there, we calculated the potential annual production that a 152.7 kWh solar system could produce throughout the year, which is 1,231,372.8 kWH of energy. However, based estimates from EnergySage, a solar system on top of Cadigan could only produce 10% of the potential energy. Using that information, we predicted that Cadigan Center would only be able to use 123137.82 kWh of energy from the panels, but would still save $16,746. 67 on their current utility bill. Over the course of 20 years, this would amount to $334,933.40 in savings. However, this number is not entirely accurate since BC would first have to break even on the investment of the solar system, which we calculated would cost around $381,750.00, as shown in Table 5. The time for BC to break even on the investment could take several years and is based on calculations that we did not have time to explore in the scope of this project. Despite the initial costs of installing a solar system, there are a few benefits that BC should consider such as the use of SRECS. In Table 6, we had predicted that the solar system would only be able to produce about 10% of what the system can potentially produce. However, if the system was able to produce excess energy, outside of Cadigan’s utility needs, then BC could lower the bill even more by using net metering. In addition, all energy produced by solar is eligible for SRECs (solar renewable energy credits), We estimated that if the solar system worked to it’s full potential, and SRECS were bought for $0.30 per kWh produced, then BC could possibly earn $332,470.66 in one year. This process of estimations and calculations were repeated for 129 Lake St., Beacon St. Garage, and St. Clements Hall. In Table 7, we analyzed the financial projections of 129 Lake St and see that the 3rd party system could save BC around $627.71 a year from the current utility bills. Over the 20 year life of the solar system, BC could possibly save $12,554.71 in total. For private ownership, BC would be able to save $35,569.98 annually and $711,399.68 over the life of the system. However, the initial cost of the system would be around $571,000.00 that would see a return on investment of around five to seven years. There is also the possibility of earning around $474,082.08 in SRECs. In Table 8, we observe the costs and savings of Beacon Street Garage. Under the 3rd party lease, the garage has the potential to save BC around $3,784.32 a year and $75,686.40 over the life of the system. With private ownership, both the Beacon Street Garage and 129 Lake St. are unique because EnergySage had predicted that both solar systems would be capable of producing 100% of the energy needed by both buildings. Therefore, the annual savings would be the value of the current energy bill itself, which, for the Beacon St. Garage, is $214,444.80 a year and around $4,288,896.00 over the life of the system. The initial cost of the system is predicted to be around $1,564,750.00 with the possibility of earning $1,041,137.28 in SRECs.
Our final analysis was on St. Clements Hall, also known as the data center on Brighton Campus. In Table 9, we predicted that 3rd party ownership would save BC around $9,820.28 annually and around $196,405.63 for the life of the system. For private ownership, EnergySage had predicted that the solar system would be able to produce around 5% of the energy used by St. Clements Hall. Even with this small percentage of energy production, the system would be able to save BC around $10,967.04 a year and $219,340.80 over the life of the system. The initial cost to the system is around $500,000 with the possibility of earning $1,203,343.20 in SRECs if the system was able to produce energy at full capacity. Table 6: The estimated pro forma model for Cadigan Alumni Center.
Table 7: The estimated pro forma model for 129 Lake St.
Table 8. The estimated pro forma model for Beacon St. Garage
Table 9. The estimate pro forma model for St. Clements Hall
Discussion/Analysis
Mention some errors in analysis to be rectified in the future
There are some imperfections in the pro forma financial estimates that need to be addressed for future analysis on such a case study. Many of the values used on the pro forma were based on generalizations of data that we had been given or research done online and may not be specific to the buildings we studied. For example, we used two different system sizes to compare 3rd party ownership and private ownership. The system size used in the pro forma for 3rd party ownership (1 MWh) was provided to us by First Wind and based on the net metering cap for non municipal and public customers. We also assumed that the solar energy company would only provide 15% of the energy produced by each building, but this value could change between solar companies and the different sizes of the system. We also estimated that the solar energy company would provide BC energy at a discounted rate of $0.12 per kWh, but this could also vary amongst different energy companies. These factors could alter the value of the savings calculated for 3rd party ownership per year and over the life of the system. The pro forma also analyzes private ownership but only provides basic costs and savings associated with owning a system. We stated the cost of the overall system for BC and the annual savings on utility bills and over the 20 year life span of the system. These basic statistics, however, are oversimplified. The annual savings under private ownership would only be experienced by BC once the entire system had been paid off, which usually varies between five to seven years depending on the size and capacity of the system. Therefore, the gross savings presented in the current pro formas could vary for each building. Further analysis of private ownership could be done through an economic cost benefit analysis to produce more accurate values on the net present value of each project. Such an analysis would provide a clearer picture on the investment in private ownership. Conclusions
Based on our findings, the most optimal location for solar panels at Boston College is St. Clement’s Hall. Even though these panels will only produce 5% of the building’s annual energy, this significantly lowers the energy bill, and means more savings over time. In addition, the carbon offset is ~521,702lbs per year. This is the equivalent to the amount of carbon 10,869 trees can absorb in a year or is the same as taking 46 cars off the road for the year (Tree Facts, 2014; Greenhouse Gas, 2011).
Third party ownership makes the most sense for Boston College because it means immediate savings rather than an initial deficit. The annual savings for private ownership are much higher but because a system is expensive to own, it would take years to pay off the initial deficit. By putting a solar PV system on St. Clement’s, BC will save almost 10,000 dollars on energy each year. Because BC would not own the panels, it would not be responsible for maintenance or other costs the panels might require. Solar is the perfect way for BC to improve sustainability while saving quite a bit of money! Acknowledgements
We would like to thank our many mentors who have supported us throughout our project’s duration: Vikram Aggarwal for aiding us with solar statistics and mathematical configurations, Peter Sullivan and Matt Marino for a pro forma that assisted us in calculating the cost of solar at different locations, and John MacDonald and Bob Pion for their advice on BC’s energy use and policy. We must also thank Professor David who gave valuable feedback and guided us through the process. References
Aggarwal, Vikram. “Solar Panel Statistics.” E-­‐mail Interview. 26 April. 2014. "Campus Sustainability Initiative." Solar Electricity. N.p., n.d. Web. 01 May 2014. <http://www.brandeis.edu/campussustainability/energy/solar.html>.
Digital image. Perth Solar Panels. Solar Panels Perth | Affordable & High Quality Solar Power Systems, 2014. Web. 27 Apr. 2014.
"Greenhouse Gas Emissions from a Typical Passenger Vehicle."Environmental Protection Agency. Dec. 2011. Web. 27 Apr. 2014. <http://www.epa.gov/otaq/climate/documents/420f11041.pdf>.
"Instant Estimate." EnergySage. Web. 27 Apr. 2014. <http://www.energysage.com/>.
MacDonald, John. "BC Energy Use Discussion." Personal interview. 10 Mar. 2014.
Marino, Matt, and Peter Sullivan. "Pro Forma Specifics." E-­‐mail interview. 14 Mar. 2014.
"One of Nation's Largest College Campus Solar Fields Being Built at Stonehill." · News & Media · Stonehill College. N.p., 6 Jan. 2014. Web. 01 May 2014. <http://www.stonehill.edu/news-­‐media/news/details/one-­‐of-­‐nations-­‐largest-­‐
college-­‐campus-­‐solar-­‐fields-­‐being-­‐built-­‐at-­‐stonehill/>. Shahan, Zachary. "Which Solar Panels Are Most Efficient?"CleanTechnica. N.p., n.d. Web. 01 May 2014. <http://cleantechnica.com/2014/02/02/which-­‐solar-­‐
panels-­‐most-­‐efficient/>.
"Solar Panel Array." N.p., n.d. Web. 26 Apr. 2014. <"St. Clement's Hall." N.p., n.d. Web. 26 Apr. 2014. .>.
"SOLAR RESOURCE DATA." PVWatts Calculator. Web. 01 May 2014. <http://pvwatts.nrel.gov/pvwatts.php>.
"Stacking the Deck." The Economist. The Economist Newspaper, 22 Feb. 2014. Web. 01 May 2014. <http://www.economist.com/news/science-­‐and-­‐
technology/21596924-­‐way-­‐double-­‐efficiency-­‐solar-­‐cells-­‐about-­‐go-­‐mainstream-­‐
stacking>.
"St. Clement's Hall." Web. 26 Apr. 2014. <http://eypaedesign.com/resources/img/projects/boston-­‐college-­‐st-­‐clements-­‐
hall-­‐4.jpg>.
"Stonehill College." U.S. News & World Report. N.p., n.d. Web. 01 May 2014. <http://colleges.usnews.rankingsandreviews.com/best-­‐colleges/stonehill-­‐
college-­‐2217>.
"Sustainability; Energy and Emissions." Harvard University. The President and Fellows of Harvard College, 2013. Web.
"The EnergySage Marketplace." EnergySage. EnergySage, Inc., 2014. Web.
"Timeline of Solar Cells." Wikipedia. Wikimedia Foundation, 30 Apr. 2014. Web. 01 May 2014. "Tree Facts." American Forests. Web. 27 Apr. 2014. <https://www.americanforests.org/discover-­‐forests/tree-­‐facts/>.