A group of researchers from the UW–Madison Office of Sustainability, the La Follette School of Public Affairs, and the Nelson Institute for Environmental Studies have partnered with two student organizations to assess potential locations on campus that might be suitable for solar panels.
“People frequently ask our office about rooftop solar,” said Josh Arnold, campus energy advisor at the Office of Sustainability. “We wanted to answer a theoretical question about how much clean electricity could be produced by campus rooftops if there were no other constraints.”
Using Google Solar API, study participants were able to visualize campus rooftops to provide a starting point for future conversations about solar feasibility. The results showed that, in theory, rooftop solar could supply much more electricity than renewables currently do on campus: between 15 and 24% of electricity could be generated using UW-Madison’s rooftops — about 3.6 million square feet of them.
As of spring 2024, renewable energy supplies 14% of UW-Madison’s electricity needs. These include solar panels installed at Gordon Dining and Event Center, the UW Arboretum, and several bus shelters over the last five years. However, the vast majority of this 14% is derived from off-campus sources such as the O’Brien Solar Field. The authors report that less than 0.1% of campus electricity usage is generated from renewables on UW’s main campus facilities, such as rooftops.
The university has conducted solar studies in the past, including for bus shelters; a high-level study of a potential solar array for the Frances Street Parking Garage; and an evaluation of a field in the Kegonsa Research Campus for building an agrivoltaic array. However, the new study is the first to assess buildings on the main Madison campus as a whole.
When the Office of Sustainability began the study, there were no active institutional sustainability goals at UW-Madison. Then, in February 2024, Chancellor Jennifer L. Mnookin announced a major initiative focused on environmental sustainability. In this context, the rooftop solar study represents an important new step in the university’s commitment to clean energy, though it is just one piece of a larger net-zero emissions strategy.
“From the start, we knew that [rooftop solar] wasn’t going to be enough to decarbonize electricity usage or achieve net-zero emissions on its own,” said Jaime Garibay Rodriguez, a postdoctoral research assistant in Professor Morgan Edward’s Climate Action Lab and lead author on the study. Rodriquez’s comments referenced the university’s goal to be 100% renewable by 2030 and reach net-zero carbon emissions by 2048 or earlier, which is two years sooner than the state of Wisconsin’s 2050 goal 100% carbon-free energy consumption.
By adding new campus-based solar projects, UW–Madison could increase the visibility and awareness of renewable energy while responding to widespread campus interest in clean energy solutions to the university’s carbon footprint.
Visualizing Possibility through Partnerships
The researchers used a state-of-the-art cloud-based tool, Google Solar API, to access the rooftop solar potential of 197 facilities across the campus. According to Rodriguez, UW–Madison was one of the first campuses to use the tool, which was released around the same time as the study implementation period.
As part of his engineering background, Rodriguez specializes in data analysis, modeling, and coding. Using algorithms to extract the data, Rodriguez and the team were able to use the most up-to-date information to capture realistic estimates of the solar potential.
The research was also the product of key partnerships, including with the Office of Sustainability interns and two student groups, Campus Leaders for Energy Action Now (CLEAN) and Helios.
Hannah Stahmann, a member of CLEAN and an intern at the Office of Sustainability, focused on translating the data into digestible language for the report, as well as promoting it at conferences and the Office of Sustainability’s annual Sustain-a-Bash events.
According to Stahmann, who is an undergraduate studies in environmental studies, she not only felt fulfillment in working on a passion project, but she was also able to increase her technical skillset.
“I hadn’t really worked much with quantitative data before,” she said. “So, it was really cool way to learn those skills without the pressure of being in a class and getting a grade for it.”
From Potential to Action
More research is necessary to evaluate whether rooftop solar is a good fit for particular locations.
“Many campus facilities are highly complex and support critical operations or long-term research that cannot be disrupted,” said Arnold. “At any given facility, we would have to account for important factors, such as the age of the facility, existing rooftop equipment or other factors, such as historic preservation requirements, as part of a determination about whether it is feasible to consider installing solar panels.”
However, by identifying the maximum technical potential, the researchers were able to answer a frequently asked question and highlight priority buildings that the university could consider for future action as it works toward its sustainability goals.
“This study is not only about focusing on one particular part of campus,” said Rodriguez. “It’s having a potential list of facilities that could be used. And then, if someone comes along and says ‘I think out of these 10 facilities, these 5 would not work because of X, Y, and Z,’ then we can look at the next 10 facilities and the next 10, and so on.”
This way, Rodriguez said, decision-makers can have a clear view of the overall picture to make informed decisions as the university works toward its net-zero emissions future.
By: Miquéla Thornton