Carbon accounting group quantifies U-M emissions


Achieving carbon neutrality at U-M means reducing emissions across a number of different areas — from improving building energy efficiency standards to electrifying U-M vehicles to providing more sustainable food options.

And while such efforts seem fairly distinct from one another, emissions resulting from campus activities, purchased power and indirect sources all add up to U-M’s total carbon footprint.

One research group is working on aggregating them all into a scenario planning model for the President’s Commission on Carbon Neutrality to use in shaping its coming recommendations.

“Our work is to build a greenhouse gas emissions model that evaluates the current baseline greenhouse gas emissions for the University of Michigan campuses, forecasts a ‘business-as-usual’ case through 2050, and then finally, evaluates scenarios to achieve carbon neutrality,” said Gregory Keoleian, a PCCN member and director of the Center for Sustainable Systems.

“Our goal is ultimately to inform the development of carbon neutrality pathways, goal years, and policies.”

Keoleian leads the commission’s carbon accounting subgroup, which initially set out to evaluate methane leakage and other upstream emissions from natural gas consumption.

Currently, the group focuses on bringing together otherwise disparate emissions data — from direct U-M energy sources, from the commission’s internal analysis teams, and from utility firms that serve U-M operations.

Carbon accounting work is nothing new for Keoleian, who advised a 2002 master’s project that proposed a framework to better measure campus sustainability across various environmental, social and economic metrics. The project involved input from more than 30 units on the Ann Arbor campus.

This subgroup’s push, however, goes beyond previous carbon accounting efforts by covering U-M’s footprint beyond Ann Arbor, accounting for indirect “Scope 3” emissions categories, and modeling carbon neutrality scenarios and pathways.

“People are most interested in when we are going to achieve carbon neutrality — what our goal year is,” Keoleian said. “This model will allow us to simulate alternate reduction pathways and provide the commission with a basis to make recommendations.”

“Part of the modeling effort was to build in different strategy options, whether electrifying vehicles, reducing food waste, or various other options,” said Nick Kemp, a recent master’s degree graduate of the School for Environment and Sustainability who is currently assisting the subgroup with its modeling work.

Kemp received his undergraduate degree from the College of Engineering and joined the subgroup with experience in the manufacturing and biomedical engineering sectors. His thesis work covered connected and automated SUVs and vans, and he has led the group’s effort to gather emissions data relating to vehicle fleets, commuting and university travel.

“Coming from an engineering background, the model is similar to a control room,” Kemp said. “There is a user interface, where we can make decisions about which carbon-reduction strategies to enact. Those decisions drive the inner workings of the model, which then generate simulated emissions trajectories.”

The subgroup’s process has not been without its share of challenges. Inputs into the model are not static. Utilities have their own emissions reduction goals, and vehicle fleets are expected to increasingly become more electric. The model had to account for these trends.

Moreover, taking data from disparate sources and standardizing it in a tangible way is no small feat. The carbon accounting model includes more than 100,000 data points and more than 500 carbon-reduction strategy input parameters. It simulates greenhouse gas emissions for 29 carbon-reduction strategies.

The model also calculates U-M’s progress toward carbon neutrality relative to the Intergovernmental Panel on Climate Change’s target of 1.5 degrees Celsius of warming.

Team members note that once the data are all in one place, emissions reduction opportunities are clearly visible.

“Reducing emissions from heating and cooling buildings is the most important step,” said Geoffrey Lewis, a subgroup member and research specialist at the Center for Sustainable Systems.

“Some emissions sources, like food and campus transportation, account for smaller fractions of total university emissions, and may have easier or less costly reduction options. But the challenge of addressing larger emissions sources should not be demotivating. Everyone needs to be involved to get us to neutrality.”

With any technical project, buy-in is key to success, Kemp said.

“Understanding the technical aspects of sustainability is important because you want to know where you’ll get the most return on investment,” he said. “We also need to have people on board and an encouraging culture on campus that includes students, professors, and especially people who aren’t actively immersed in the technical work behind carbon neutrality.”

The carbon accounting subgroup also includes Stephen Hilton, Nate Hua and Michael Mazor, all of the School for Environment and Sustainability.

The carbon commission expects to make its draft recommendations available for public comment this fall and deliver its final report in February 2021.


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