2. Methods & Approaches

References: 1. “PVWatts Calculator,” NREL, http://pvwatts.nrel.gov/pvwatts.php.2. “Building Energy Data”, Office of Campus Sustainability,

http://sustainability.umich.edu/ocs/building-energy.3. “Greenhouse Gas Calculator”, EPA,

https://www.epa.gov/energy/greenhouse-gases-equivalencies-calculator-calculations-and-references.

4. Mark Lindquist, “Draft Image for Solar Carport Model”, University of Michigan, 2018.

Acknowledgements: We thank the University of Michigan Earth and Environmental Science Department, the University of Michigan Energy Institute, Adam Simon, Susan Fancy, Nick Soberal, Peter Knoop, Mark Lindquist, Andy Berki, Andrew Horning, Ken Keeler, Steve Skerlos and the rest of the Clean Wolverines for providing support and feedback on this research.

1. IntroductionSolar power is the use of the sun’s energy and photovoltaic cells to generate electricity. This

process provides electricity without emitting harmful greenhouse gases, and is economically

efficient as the photovoltaic cells are a one time purchase for upwards of 30 years of free

electricity. The Clean Wolverines believe that the use of solar photovoltaic cells on campus is a

way to advance the University of Michigan’s (U-M) sustainability goal of reducing greenhouse

gas emissions by 25% from 2006 levels by 2025 and help reach their eventual goal of carbon

neutrality. The Clean Wolverines have modeled how the use of solar arrays on U-M’s campus

could put U-M closer to their goals. To show this, the available area of 36 building rooftops, and

26 parking lots and parking structure spaces were modeled using ArcMap, a type of Geographic

Information System mapping software. From these calculations, the available area of the space,

solar output of each space, total installed system capital costs and the mitigated greenhouse

gases were calculated. Through these calculations, the Clean Wolverines have come to the

conclusion that investing in solar technology carports for parking lots and structures across

campus is the most cost effective and worthwhile way to incorporate solar energy into U-M’s

energy mix.

8. Conclusions

The Fe and O stable isotope data for magnetite at El Laco indicate that the ore forming fluids were sourced from a magmatic reservoir, and preclude the necessity of an isotopically unique melt. The wide range of O and H isotopic values suggest isotopic fractionation among magnetite textures as well as post-deposition alteration. Further, these data are in agreement with historical O isotope data from Rhodes and Oreskes (1999) and Tornos et al. (2016). The stable isotopes of El Laco are readily comparable to Chilean IOAs (as well as IOCGs) from both the Mesozoic and Cenozoic.

3. GIS Study

GIS (Geographic Information System Mapping Technology) is a computer software and web

application by Esri that allows you to gather and analyze data on the rooftop or ground area of a

building, parking structure or parking lot.

The bulk of the data collection was done using ArcMap, a GIS software by Esri. We collected the

data by drawing 62 polygons that represented rooftops or land space on the University of

Michigan’s south, central, medical and north campuses. Polygons are spatial drawings of vector

data in a single plane that represent the usable area (in square meters) of a space on a map of

Ann Arbor and U-M’s campus. They were drawn on south-facing rooftops while avoiding any

obvious rooftop obstacles such as HVAC systems or uneven ground. They were also drawn on

parking lots and parking structures. From the usable area (in square meters) measurements

acquired from ArcGIS, analyses were performed to determine the usable square meterage of the

space, solar output if each space was converted to solar arrays, the DC system size, total installed

system capital costs and the quantity of greenhouse gases mitigated.

7. University Recommendations

4. Results

Total of all 62 Polygons1. Usable Area: 145,000 square meters 2. Solar Output: 25,000,000 kWh/yr3. DC System Size: 21,700 kW4. Current CO

2 Emissions: 136,000 MTCO

2/yr

5. CO2 Mitigated: 18,600 MTCO

2e/yr

All Buildings1. Usable Area: 40,200 square meters 2. Solar Output: 7,200,000 kWh/yr3. DC System Size: 6,300 kW4. Current CO

2 Emissions: 131,000 MTCO

2/yr

5. CO2 Mitigated: 5,360 MTCO

2e/yr

All Parking Lots and Parking Structures1. Usable Area: 98,300 square meters2. Solar Output: 16,700,000 kWh/yr3. DC System Size: 14,800 kW4. Current CO

2 Emissions: 4900 MTCO

2/yr

5. CO2 Mitigated: 12,400 MTCO

2e/yr

Top 5 Parking Lots1. Usable Area: 44,300 square meters2. Solar Output: 7,360,000 kWh/yr3. DC System Size: 6,650 kW4. Current CO

2 Emissions: 0 MTCO

2/yr

5. CO2 Mitigated: 5,470 MTCO

2e/yr

Implementing solar energy at the University of Michigan is feasible, and it is economical to construct solar carports on top of large parking lots owned by the university. The Clean Wolverines used GIS technology to map areas to place solar panels, and have found high returns on campus parking lots on the North, Medical and South campuses. Including solar panels at these areas will help the University of Michigan strive to meet the 2025 sustainability goal of 25% reduction in greenhouse gas emissions and the eventual future goal of university carbon neutrality.

6. Implications

In 2011, the University of Michigan created 2025 sustainability goals, one of which is to reduce greenhouse gas emissions 25% below 2006 levels. In 2006, U-M produced 680,000 MTCO

2e and in 2017 produced 636,956 MTCO

2e, which is roughly a 5% reduction in emissions

in 10 years (See Figure 1). The implementation of solar energy on U-M’s campus has the potential to help power the university and reduce overall greenhouse gas emissions. For implementing solar energy at all 62 spaces analyzed, 18,601.9807 MTCO

2e per year of

greenhouse gas emissions would be avoided, which is approximately 3.16% of U-M’s current total greenhouse gas emissions (See Table 1).

Additionally, implementing solar energy as solar carports on top of the five largest parking lots analyzed: NC51, M71, SC4 and SC5, SC7, and NC37, would mitigate 5,472.84 MTCO

2e per year

of greenhouse gas emissions, which is estimated at 0.93% of U-M’s current total greenhouse gas emissions (See Table 1). Reducing greenhouse gases is a sustainability priority for the University of Michigan and implementing solar carports is the best option for solar energy on campus to reduce emissions and promote renewable energy on campus.

1. GIS spatial analysis on ArcMap - Mapped the area (in square meters) of 62 buildings, parking lots, and parking structures on the University of MIchigan campus (See detailed description below in section 3).

2. Excel data compilation of results from ArcMap to calculate DC system size, solar output (conservative and optimal), current energy use per year, current carbon-dioxide emissions per year, carbon-dioxide emissions mitigated by solar energy (conservative and optimal), and various all-in upfront costs of solar arrays:a. DC System Size (kW) - calculated using PV-Watts calculator through NREL1 to measure

overall capacity of the solar arrays. Assumptions from NREL include 15% module efficiency for standard crystalline silicon solar panels.

b. Solar Output (kWh/yr) - calculated 50% usable area (in square meters) for parking lots and structures, and 30% (conservative) and 62.5% (optimal) usable square areas for buildings. 166 kWh/m^2/year assumption for solar panels on carports at a 7-degree tilt, 179 kWh/m^2/year assumption for solar panels on roofs at a 34-degree tilt.

c. Current Energy Use Per Year (kWh/yr) - numbers obtained from U-M Office of Campus Sustainability Building Energy Data2.

d. Current Carbon Dioxide Emissions Per Year (MTCO2e/yr) - numbers obtained from U-M Office of Campus Sustainability Building Greenhouse Gas Emissions Data2.

e. Carbon Dioxide Emissions Mitigated by Solar Energy - calculated by multiplying the solar energy output for conservative and optimal levels with the conversion factor = 0.000744, which is the emissions factor for carbon dioxide that is mitigated by renewable energy from the EPA4 .

f. All-In Upfront Costs - include capital costs for solar carports priced at a range of $2.25 - $2.50 per watt capacity for solar carports. Assumptions were obtained from Wayne Appleyard and Michigan State University’s implementation of solar carports.

Through our GIS exploration of solar potential for U-M’s buildings, parking structures and parking lots, we found that the optimal and most feasible course of action for U-M regarding on-campus photovoltaic installation is to install solar carports on five of U-M’s largest parking lots. We conclude that the five largest lots are North Campus 51, South Campus 4 and 5, Medical Campus 71, South Campus 7, and North Campus 37, in order largest to smallest.

Placing solar carports on top of the five largest parking lots with the greatest solar potential would enhance the university's renewable energy portfolio, and provide additional protection from Michigan weather for cars and vehicles that park in the lots, without compromising the number of parking spaces. This investment would lead to the installation of 11 acres of solar glass on U-M’s Ann Arbor campuses, thus demonstrating to students, alumni and the Ann Arbor community that U-M is committed to its sustainability goals, supportive of renewable energy technologies, and looking towards the future.

Figure 1

Table 1

The 62 polygons shown here represent all the U-M buildings, parking structures and parking lots that we chose to include in our GIS analysis. This scenario is not feasible because it is not economical to put solar on all buildings and parking lots. These results can be used as a thought experiment to show what could happen on U-M’s campus if all 62 structures had solar panels installed.

The 26 polygons analyzed represent all the parking lots and structures on U-M’s campus that we chose to include in our GIS analysis. The current greenhouse gas emissions from these structures are minimal and placing solar on all parking lots and structures would mitigate almost 3 times the greenhouse gas emissions currently produced by these parking lots and structures.

The top 5 parking lots were spaces on the north, medical and south campuses of U-M. They would produce roughly 1.5% of the university’s total electricity consumption if solar carports were placed at these sites. Currently there is no greenhouse gas emissions from the parking lots and placing solar carports at each site would mitigate 5,470 MTCO

2e/yr of the university’s total

greenhouse gas emissions.

The 36 polygons analyzed for roof space were for buildings that had optimal south-facing roofs for solar panels. Placing solar panels on rooftops at U-M is not entirely feasible because of the historical significance of most of the buildings and the load of solar panels could jeopardize roof integrity. Analyzing the potential for solar panels on U-M roofs shows the theoretical possibility of implementation at the university.

For the top 5 parking lots with the highest potential for producing solar energy, solar carports present an opportunity to incorporate more renewable energy while also mitigating greenhouse gas emissions at the University of Michigan. The carports would increase the university's renewable energy consumption while also mitigating greenhouse gas emissions.

To cite industry specialists, the all-in upfront cost for solar carports is approximately $2.25 per watt capacity to $2.50 per watt capacity. These costs reflect construction and cost of the silicon crystalline panels, but do not reflect operation and maintenance costs.

Benefits of Solar Carports1. Space saving solution in urban city pressed for space2. Solar carports will not decrease the number of

parking spaces in any of the lots.3. Panels provide increased coverage for vehicles from

inclement weather like sun, rain, and snow.4. Panels provide increased coverage for the parking

lot itself from inclimate weather thus decreasing maintenance costs over time.

5. Electric vehicles could plug in directly at parking lots and access truly renewable energy on site.

6. Act as a visual demonstration of the university's efforts to implement renewable energy on campus.

Challenges for Ground-Level Solar Panels1. Additional costs associated with leveling the ground

and deforestation.2. Land used for ground-level panels takes away land

that could be used for other university development.

3. Visibility by the Ann Arbor community is not guaranteed for panels that are on ground-level.

GIS Solar Analysis for University of Michigan Campus

Lydia Whitbeck1, Elena Essa2, Adam Simon3, Susan Fancy4

University of Michigan Dept. Program in the Environment1, University of Michigan Dept. of Statistics2, University of Michigan Dept. of Earth and Environmental Sciences3, University of Michigan Energy Institute4

3-D visualization of solar carports

5. Solar Carports