# Math Students Try to Find Solutions to a Range of Environmental Challenges

June 1, 2018

In spring 2018, students in Professor of Mathematics Victor Donnay’s course Math Modeling and Sustainability learned how to analyze problems of environmental sustainability using mathematics. This was a Praxis course with the students working in teams to assist a community partner in examining a sustainability problem.

The Comcast Team (Ingrid Bethuel '18, Madeline Cherniack '19, Adele Hu '18, and Sohini Maniar '18) partnered with Bryn Mawr math alumna Alexandra (Allie) Wiegel '16 who works in Comcast’s sustainability division. The division is headed by Chief Sustainability Officer Susan Jin Davis '86, a trustee of the College. Comcast’s sustainability team is constantly exploring opportunities to reduce the company’s impact on the environment while also improving the communities where they serve and their customers' experiences. For this project, students helped Comcast understand the financial implication of moving to a fully electric fleet. Comcast has one of the largest fleets in the country, producing large quantities of greenhouse gas. For this project, students outlined how switching to an electric fleet, which would produce fewer harmful emissions, would also make financial sense. A key finding was that operating an electric vehicle is much less expensive (\$672/year) than a gas powered vehicle (\$3,247/year).

The EQUAT Team (Hee-Eun Kim '19, Charlotte Lin '19, Maia Rabinowitz '20, and Nithya Sivakumar '19) worked with Bi-Co alumni Ryan Leitner (HC '16) and Ben Safran (HC '13). EQUAT stands for Earth Quaker Action Team and is a social justice organization. EQUAT is engaged in a campaign to get the PECO energy company to increase the amount of energy it generates from renewable sources, presently at four percent, to 20 percent by 2025. The students were asked to calculate the “social cost” of PECO’s energy portfolio, where social cost is a measure of the negative impact that CO2 emissions have on society (estimated by the EPA to be roughly \$40 per metric ton of CO2 emissions). The students estimated that if PECO does not change its energy mix (which currently includes 31 percent coal, 31 percent natural gas, four percent renewables plus nuclear), the social cost in the decade 2025-2035 would be \$6.5 billion. If PECO increased their renewables to 20 percent and decreased their coal use by a corresponding amount, the social cost to society over that decade would drop to \$2.9 billion, a savings of \$3.5 billion.

The Freight Farm Team (Leah Baker '19, Jill Li '18, Natalie Meacham '19, and Bisma Naqvi '18) worked with student Mary Cuigini ’20 to examine the costs and benefits of having a freight farm system on campus. A freight farm is an upcycled shipping container repurposed to grow produce using hydroponics. The team proposed using the system to grow fresh produce for the dining halls, thereby reducing the College’s purchasing costs as well as reducing its carbon footprint, since produce would not have to be trucked from far away. Although the initial cost of the freight farm system was high (\$85,000), the students made the case that the savings over time combined with the less quantifiable benefits (educational opportunities for students who would use the farm as a living laboratory and raising the College’s sustainability profile) would make the freight farm a positive investment.

The Solar Team—Shannon Fischer '20, Hezel Gadzikwa '18, Henry Nye (HC '20), and Kaitlin Reese (HC '20)—worked with Mardi Dietze and Paul Clee from Philadelphia’s Office of Sustainability. As part of its GreenWorks sustainability master plan, Philadelphia is committed to reducing its carbon footprint and is eager to develop more renewable energy. The students’ project was to determine which city-owned buildings would be most suitable to be equipped with solar panels. Interestingly, the majority of the buildings in their top 10 list turned out to be correctional facilities. They projected that solar panels on their #1 building, the Philadelphia Detention Center, could produce a savings of \$170,000 per year in electricity costs.

The Storm Water Team ( Namrata Basu '19, Amelia McCarthy '19, Maria Minaya '19, and Emily Shinault '18) worked with  local environmental engineer Derron LaBrake to investigate flooding in the Chatham Glen area of Havertown. They examined whether the installation of rain gardens in peoples’ yards, uphill from the flood-prone region, would significantly reduce the flooding. They found that rain gardens alone, even if one were placed in every yard in the area, would not divert enough water to prevent flooding. However, if one combined the rain gardens with mitigation efforts on Township-owned land, then the risk of flooding would be significantly reduced.

This summer, Donnay will continue building on the relationships he has developed with Philadelphia's Office of Sustainability. He will work with math major Meagan Murray-Bruce '20 who will be carrying out a cost-benefit analysis of converting street lights in Philadelphia to LED bulbs. She will be analyzing data collected by the city's Streets Department.