Cornell can use circular resource management to achieve its goal of carbon neutrality by 2035, according to a recent study, published in the Journal of Cleaner Production, by Fah Kumdokrub grad, a third-year Ph.D. student in the Systems Engineering department.
Using the campus as a “living laboratory,” Kumdokrub tracked resource flows in three sectors — construction, energy and food waste — and proposed sustainable alternatives that do not require much oversight to implement.
Resource circularity prevents materials and energy from becoming waste. As resource consumption increases, the need for circularity increases in order to prevent a corresponding rise in waste. This is especially pertinent when it comes to the energy sector, which accounts for two-thirds of the University’s carbon footprint and is projected to expand in the future.
Cornell has implemented several renewable energy projects in an effort to replace nonrenewable sources. In 2000, the University installed Lake Source Cooling, which replaced energy-intensive refrigeration equipment with a system that utilizes the deep cold waters of nearby Cayuga Lake.
Despite these efforts to incorporate renewable energy sources for cooling, Kumdokrub’s research shows that the University still heavily relies on natural gas for electricity and heating. Her research recommended that Cornell fully commit to more renewable alternatives, which the University is currently exploring.
In June 2022, the University drilled a two-mile deep borehole near the Veterinary College, allowing scientists to determine the viability of heating the campus with geothermal energy. If proven feasible, geothermal energy could fulfill the majority of heating and electric demand and eliminate the reliance on natural gas supply, according to Kumdokrub’s study.
The energy sector also accounts for emissions produced by daily building operations such as electricity, air conditioning and lighting. However, it neglects the emissions created by the construction of the buildings themselves, also known as “embodied emissions,” which refer to the way a building is constructed rather than how it is used.
“The [buildings themselves] carry a lot of embodied emissions, which we don’t consider as part of Cornell’s total emissions,” Kumdokrub said. “If we want to truly achieve carbon neutrality then we should also start to look at these kinds of issues, as well.”
Kumdokrub suggests implementing policies for low-to-carbon-positive building materials to scale back on construction waste.
However, construction and energy waste cannot always be effectively converted back into raw materials. Similarly, food waste inevitably includes inedible scraps such as peels and bones. In such situations, waste can be converted into energy and enhance circularity.
According to Kumdokrub, Cornell’s current approach to food waste involves sending waste directly to compost fields. Although this is a more sustainable alternative to landfill disposal, traditional composting still releases greenhouse gasses and misses a key energy recovery opportunity. Kumdokrub’s research suggests a more sustainable solution known as anaerobic digestion, which the Environmental Protection Agency ranks above traditional composting for food recovery efforts.
Instead of sending food waste straight to the compost field, anaerobic digestion passes the waste through a digester, separating it into renewable gas and a solid byproduct known as digestate. The gas can be used for electricity and heat generation while the digestate can be sent to the compost field as an organic fertilizer.
Kumdokrub sees the potential to leverage an existing digester at the Ithaca Wastewater Treatment Plant, eliminating the need for new infrastructure. According to her study, digestive composting could save $90K to $400K a year due to lower composting costs and higher revenue from the fertilizer produced.
However, digestive composting presents some challenges, including the digester’s restricted capacity to handle agricultural waste and the need for official safety verification for the use of digestate as a fertilizer.
Despite its limitations, Kumdokrub’s analysis of resource flow on Cornell’s campus serves as an example for other universities looking to identify their most energy-inefficient sectors. The study suggests renewable energy sources to daily operations but also underscores the importance of considering building construction over operation alone.
“Cornell is already getting a start in terms of renewable energy,” Kumdokrub said. “I just want to point out that the structural part is also important. It’s not really common for other institutional settings [to track] because it’s a really complex issue, but it’s an interesting problem that should be studied more.”
Ellie VanHouten can be reached at [email protected].