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The geothermal system is an underground roller coaster of pipes that transports water around campus and through the college’s central heating plant in order to heat and cool buildings and provide hot water. Creating the closed-loop system involved digging 850 geothermal wells beneath one of the practice fields on north campus. These wells, which drop 600 feet into the Earth, allow water in the pipes to pull heat from the Earth in winter and shed it in the summer. No matter the season, the temperature of the Earth remains the same, so the water leaving this field is approximately 55 degrees Fahrenheit. The central heating plant then uses heat pumps to chill or warm the water, which circulates through campus before reaching the field, where the loop repeats.

Geothermal energy is one of several sustainable energy sources 91ֱ�� is using to reduce emissions; for example, the college also has multiple solar arrays. While McTiernan stresses that a small amount of greenhouse gas emissions are inevitable even with alternative energy—among other things, you might still need to use backup generators in extreme weather—91ֱ�� has been successful using infrastructure to neutralize its carbon output. All told, the college has reduced roughly 90 percent of campus’s total emissions by switching to alternative energy sources.

“[91ֱ�� has] taken on the hardest part of the work by actually reimagining some of the most greenhouse gas-intensive systems in their footprint and fundamentally redoing them in such a way that deeply decreases emissions,” McTiernan says. “That is the way to do it.”

To reach 100 percent carbon neutrality, institutions typically purchase carbon offsets, a transaction that involves paying another entity to reduce or remove a quantifiable amount of greenhouse gas emissions. Making sure that the offsets are high-quality is essential, says Claire Jahns ’03, whose background is in climate economics. “Offsets should be quantifiable, measurable, and verifiable; otherwise, they’re not good offsets.”

91ֱ�� partnered with its natural gas supplier to purchase high-quality offsets from a third party to cover things like gas used for on-campus buildings not connected to SIP. To account for things like employee travel (e.g., business trips and daily commutes) that contribute to the college’s total emissions, 91ֱ�� chose the offsets provider Tradewater, which captures and destroys potent greenhouse gases like refrigerants and plugs up abandoned oil and gas wells that leak methane gas. In other words, these offsets are actively, permanently removing carbon emissions.

Thanks to the college’s extensive, up-front infrastructure work, 91ֱ�� had to purchase only a very small number of carbon offsets—far fewer than many other colleges and universities that have reached carbon neutrality. This impressed Bridget Flynn, a former sustainability officer at the college, now a climate programs senior manager at Second Nature, a nonprofit that works with 91ֱ�� and other higher education institutions on carbon neutrality and resilience. “91ֱ�� is an example that other campuses will be able to use, demonstrating tangible decarbonization on campus is possible.”

Further analysis indicates that 91ֱ��’s geothermal system not only reduces carbon emissions, but also saves 5 million gallons of water and 4 million gallons of sewage simply because steam isn’t leaking from old pipes. That’s another reason a major infrastructure project like this is so important, says Gavin Platt ’06, vice president of design at Acuity, which creates sustainable building management systems.

“Physical buildings and their supporting infrastructure don’t change very often,” Platt says. “How we manage our buildings and optimize their performance is usually the biggest and only lever we’ve got.” Greater change is possible when you have more levers, he adds: “Sustainability is both technical and cultural. It’s about infrastructure and policy, but it’s also about people and behavior.”

A town-gown partnership

A great example of that is the relationship between the college and the city of 91ֱ��. “The city’s climate action plan is, in effect, the college’s climate action plan,” says Chris Norman, the college’s senior director of energy and sustainability. The college contributes about 25 percent of the city of 91ֱ��’s total greenhouse gas emissions, so the two entities have been intentionally working together on sustainability projects for decades. Among other things, this included the 91ֱ�� Project, an early—and catalytic—town-gown partnership on sustainability; additionally, the city sold all of its renewable energy credits to the college in 2005.

Committing to green energy has required taking risks; for example, in 2008, 91ֱ�� City Council voted down a new coal plant contract and started sourcing contracts for alternative energy. “Doing the SIP and getting to carbon neutrality would have been really difficult without the city’s carbon-free electricity,” says Heather Adelman, the college’s sustainability manager and an associate director of the 91ֱ�� Project. “The leadership it took on the part of the city, where they made long-term commitments to green energy, was crucial.”

That relationship is key, says Brian Pugh ’08, the mayor of Croton-on-Hudson, New York, a village about the size of 91ֱ��, which he has led to become the No. 1 clean energy community in New York state. “The fact that a village of a little over 8,000 people is able to do things like this shows that it can be done,” Pugh says, “91ֱ�� would probably say the same thing—if a small liberal arts college in the Midwest can do this, maybe some of the mighty universities of the East and West with multibillion-dollar endowments could do the same.”

For a small town, having a large stakeholder like a college interested in purchasing green energy creates essential financial backing for sustainability projects. Pugh’s village works with Columbia University; 91ֱ�� College, meanwhile, was that anchor for the city of 91ֱ��’s first renewable energy credits. It’s a mutually beneficial relationship: The college ensured that its electricity came from a renewable source; in turn, this helped the city invest in long-term renewable energy contracts for electricity.

Jahns had been pushing for renewable energy credits decades ago while still a student. She was at 91ֱ�� right after the signing of the Kyoto protocol, the first international agreement for nations to reduce carbon emissions. In response, Jahns formed a student activist group, Climate Justice, and worked with the campuswide sustainability group to get the college to reduce emissions.

“One of my final memories of 91ֱ�� is when I graduated in 2003,” she says. “I walked across the stage to accept my diploma, and I shook [then-91ֱ�� president] Nancy Dye’s hand, and she said to me—while handing me my diploma—‘We’re going to go ahead and buy those renewable energy credits,’ which is something Climate Justice had been really pushing for.”

Jahns, who founded the climate change strategy consulting firm Scale, is impressed with how the college has continued that commitment, which had seemed almost “pie in the sky” then. That 91ֱ�� partially funded SIP using green energy bonds—becoming only the second higher education institution approved to use them to fund sustainable infrastructure—impresses her even more.

“91ֱ�� can teach other small and medium-sized institutions about how to leverage investor interest and climate finance to make really clear and permanent emission reductions possible,” Jahns says. “To see this massive investment in infrastructure—really transformational for the college’s infrastructure, period, but also for student life—the contributions that can have to student educations at 91ֱ�� and careers afterwards is monumental.”

On-campus support

The impact of what happens next at 91ֱ�� is hard to quantify, but having this project physically on campus is important, says Justin Mog ’96, director of sustainability initiatives at the University of Louisville. “On-campus things always have to be the first priority,” he says. “That’s where you discover these things and learn to care about them. It’s not just about the infrastructure of the campus; it’s the infrastructure of our minds.”

One of his memories of 91ֱ�� is the smell from the facilities plant. “Especially on cold nights, I remember I could taste the sulfur in my mouth from the coal burning on campus,” Mog says. At the same time, he was in the design charrettes for what became the AJLC, dreaming of a building that produced more energy than it consumed. “To see how far the college has come since then is really so inspiring, and I’m not surprised to see that 91ֱ�� is leading the way on sustainability.”

Mog emphasizes that having buy-in over time from the college administration also helped the college achieve carbon neutrality. “It makes all the difference in the world,” he says, although he also credits the constant push of 91ֱ�� students toward sustainability as one thing that shapes how the college reached its goals.

As a student, Gavin Platt was integral to the development of the technology that now drives the Environmental Dashboard, a campuswide energy monitoring system that shows electricity and water usage in real time.

“The overall idea was to make energy use more visible so students could connect their daily choices to 91ֱ��’s broader sustainability goals,” he says, noting that this experience led to his career in sustainable management systems. “It taught me that even small shifts in awareness can ripple outward and support larger systemic changes. As a student, I didn’t fully understand just how difficult these things were to pull off, and it’s humbling now to know how slow change could be. Looking back, I’m glad to have played a small part in it.”

Current students can take a course with Professor of Psychology and Environmental Studies Cindy Frantz called Advanced Methods in Community-Based Social Marketing. As part of the class, students design and evaluate programs to promote sustainable behaviors like using cold water to wash clothes and taking shorter showers. Their research has led to tangible, campuswide programs, Adelman says, like stickers explaining when it’s efficient to have windows open, and a ban on single-use plastic water bottles.

Moving forward, 91ֱ�� has more work to do with the geothermal system, including connecting additional buildings and optimizing the system for efficiency. In the future, the college plans to transition the rest of the maintenance fleet to electric vehicles and imagine campus landscaping for biodiversity and resilience in extreme weather. Meanwhile, the city of 91ֱ�� is talking about building an eco-industrial park with a geothermal system built in from the start.

Starting in mid-October, UL Verification Solutions (UL Solutions) also embarked on a third-party review of 91ֱ��’s carbon-neutral status for 2025. This verification ensures the college continues to be on track with its sustainability goals—and going forward will be a model for other places to replicate.

“91ֱ�� is a laboratory for the future,” Platt says. “Smaller institutions like 91ֱ�� can be test beds for innovation. That’s what we did there. And as it turns out, what happens on campus doesn’t stay on campus. Students carry those lessons into the world, and other schools and communities notice.”

And, as Florini notes, having real-world examples makes all the difference —“especially in responding to people who say it can’t be done,” she says. “The best response is to say, ‘Well, actually—we just did it.’”

This article originally appeared in the .

Dyani Sabin ’14 is a freelance science journalist, an author of speculative fiction, and one of the first residents of the Kahn Sustainable Living dorm.