A recent UNC alum’s published paper details how electric school buses can strengthen the state’s electrical grid.
By Colton Hartzheim
CHAPEL HILL, N.C. – Melanie Elliott took a risk when she left her job as a Starbucks store manager to study physics and astronomy at UNC-Chapel Hill in 2017, but she refused to stay in a career in which she felt unfulfilled.
Elliott’s classes and research at UNC helped her discover a new passion: sustainability. In her final year as an undergraduate, Elliott worked with her research adviser Noah Kittner, an assistant professor in the Department of Environmental Sciences and Engineering, to study and analyze how electric school buses’ batteries can help meet energy demands in North Carolina.
In their paper, which the journal Sustainable Production and Consumption published in December 2021, Elliott and Kittner found that electric school bus owners can charge and discharge their batteries at strategic times of the day to help power distributors meet energy demands in North Carolina.
When Elliott first came to UNC, she pursued her childhood interest in astronomy by majoring in astrophysics. But when Elliott read about the first picture ever taken of a black hole in April 2019, she found this major astronomical achievement underwhelming.
“It felt like one of the most important astronomical developments in my lifetime, and yet, it felt like it doesn’t really impact our life on Earth,” Elliott said. “It just feels like there are more pressing issues on this planet that we need to get to first.”
Elliott turned her research toward these issues. She realized that she could use her skills in physics to research sustainable energy. To Elliott, working on sustainability seemed to have the most impact on cutting the earth’s greenhouse gas emissions.
Elliott secured an internship for the summer of 2020 with the Electric Power Research Institute, a nonprofit organization that researches environmentally-friendly electricity generation and distribution. It felt as if she was on the right track to finding a fulfilling career. But when the pandemic canceled the internship and everyday life, Elliott had to find a new route. She took a Maymester course on energy policymaking to fill her time.
One day in class, her public policy assistant professor Evan Johnson lectured about charging electric vehicles. Electric vehicle owners charge their batteries by connecting their vehicles to a charging station. Electricity flows from power plants to charging lines to these stations through what is called the power grid. That day, Johnson also taught the class about vehicle-to-grid (V2G) technology, through which electric vehicles discharge energy from their batteries and back into the grid. Elliott found this technology fascinating but confusing.
“What is this vehicle-to-grid stuff?” she asked Johnson one day after class. “How does it benefit anybody?”
She said Johnson told her: “You know, I don’t really know either, but you should check it out and report back to me what you find.”
Elliott did just that. She found through her research that V2G technology stabilizes the grid because it ensures there is more energy readily available whenever local consumers need it. This is especially important when there is high electrical demand. Elliott found free software from Lawrence Berkeley National Lab to model how vehicle-to-grid services work, a useful program amid COVID pushing everything online. She figured this would be an ideal way to fulfill the research required for her to graduate and presented some preliminary research to her research advisor, Noah Kittner.
“It doesn’t look like this COVID thing is going to be clearing up anytime soon,” she told him. “I need to find something that I can do remotely and on my own. What do you think of this?”
Kittner approved, and Elliott continued her work, shifting her focus to electric school buses.
School buses operate on strict schedules, have large batteries and are stationary for most of the midday and summer. Elliott’s research finds that this makes electric school buses great candidates for returning energy to the grid. These fleets of school buses can charge their batteries in the morning when electrical demand is low and discharge to the grid using V2G technology in the afternoon when electrical demand is high. Doing so can provide about 2.6 thousand megawatts of energy to the grid on an average winter weekend day in North Carolina, or about 30% of the total energy the state needs on a day like that.
Jennifer Rennicks, the senior manager of government affairs at the World Resources Institute (WRI), also recognizes how beneficial electric school buses can be to the grid. At UNC’s 2022 Clean Tech Summit on March 29, Rennicks discussed the WRI’s initiative to electrify the United States’ school bus fleet by 2030.
Although less than 1% of the country’s nearly 500,000 school buses are electric, Rennicks is hopeful. With the introduction of North Carolina’s first electric school bus on March 23, Rennicks believes that the state is on track to developing a fully electric fleet whose energy can help during natural disasters.
“When we have the next big hurricane, and we will, we could have evacuation centers that are being powered by these buses and keeping people online and safe,” Rennicks said.
Elliott and Kittner also found health benefits to electrifying school buses. With diesel-powered school buses, fumes are up to 15 times more intense inside the bus than outside the bus, according to Elliott and Kittner’s paper. As a result, students on the bus may develop asthma, cancer or cardiovascular issues. Elliott and Kittner say that electric school buses would be safer for passengers.
Ryan Westrom, the Head of Mobility Engagement for East Coast, City Solutions at Ford Motor Company, agrees. As a panelist at UNC’s 2022 Clean Tech Summit, Westrom spoke about how electric vehicles would not only be better for people’s health but also their communities.
“I remember those diesel fumes, and the smell is not pleasant,” he said. “The noises buses and trucks make are loud noise pollution. Imagine a world where you don’t hear the garbage truck anymore, except for when it’s loading.”
Elliott says she is proud of the paper she and Kittner wrote.
“As a scientist, one of the most important, if not the most important thing that you can achieve is publishing papers so that you can show your work is peer-reviewed,” she said. “I’m really proud that I published a paper because it wasn’t something I ever thought I would achieve.”
Today, Elliott works for UNC as a sustainability analyst for Sustainable Carolina at UNC. She said several teachers throughout North Carolina have read her paper and emailed her saying they are writing to their school districts to implement electric school buses.
“I’m just excited about the buzz that it’s created, and I hope that it’s actually gonna go somewhere.”
This article was written by Colton Hartzheim, a UNC senior journalism major from his attendance at the 2022 UNC Cleantech Summit.