Major Construction Underway for New Geo-Exchange Energy System

Princeton University is investing hundreds of millions of dollars below our feet, digging holes 600 and 850 feet deep for two new state-of-the-art geo-exchange systems. They make up one of the biggest components of the University’s plan to achieve net-zero carbon emissions from campus by Princeton’s 300th anniversary in 2046. 

Currently, the University runs a steam distribution plant and a cogeneration system within the central energy plant to produce electricity and steam for the campus, but some parts predate World War I. Rather than rebuilding what is now considered mediocre technology, the University sought out something newer and better. 

Enter geo-exchange. Thousands of holes, or bores, are being dug underneath the south side of campus near Fitzrandolph Road and across Lake Carnegie at the new Lake Campus. Once the bores are in place, long tubes bent in a U-shape will be inserted and filled with water to capture and store heat in the ground. That stored heat, along with heat pumps and thermal energy storage tanks, will be used to heat and cool buildings. Also underway is the conversion of campus buildings to utilize this hot-water system rather than steam.

The Thermally Integrated Geo-Exchange Resource (TIGER) facility on Fitzrandolph is expected to be completed in May 2023, while the Central Utility Building (CUB), which will distribute hot and cold water to the new Lake Campus buildings, should be finished this fall. The Lewis Center for the Arts, Lakeside Graduate Housing, and the Lawrence Apartments are already operating on geo-exchange. 

The systems are extremely energy efficient, and, since most of the equipment is housed underground, the land above can be used for other purposes, including athletic fields and a parking garage. Part of a burgeoning trend of geo-exchange systems in higher education, Princeton’s system is one of the largest, according to a February article on the Energy News Network website.

“We always talk about Princeton as a lighthouse institution that people pay attention to,” said Forrest Meggers, an associate professor of architecture and the Andlinger Center for Energy and the Environment, who also serves as co-chair of the Princeton Sustainability Committee. As a result, the University was “willing to take the more expensive pathway, because it’s important.”

An exact figure for Princeton’s new systems was unavailable, according to Thomas Nyquist, executive director of facilities engineering, though he said it was “hundreds of millions of dollars.” 

This doesn’t mean the old infrastructure is going away, according to Ted Borer, Princeton’s energy plant manager, who noted that having on-site power generation during Superstorm Sandy in 2012 was vital.

Meanwhile, students and faculty are testing and measuring the old and new systems as part of the Campus as Lab initiative, which uses Princeton’s campus for sustainability research and experiential learning. Meggers’ research was key in determining the depth at which to dig for the most efficient and cost-effective geo-exchange bores.

“Some of my colleagues complained about how noisy the geo-thermal drilling was in the summer. And I’m like, ‘Are you kidding me? Do you know how important this is to carbon emissions?’” Meggers said. “I think there needs to be a little more ‘we’re going to save the world’ attitude about the project.”

Not all of the University’s neighbors agree. Last July, Helen Nissenbaum, a local resident, filed a lawsuit to prevent the construction of the TIGER facility due to noise concerns and zoning issues. The plaintiff’s complaint was dismissed by the Mercer County Superior Court, which upheld the Princeton Planning Board’s decision on March 29. 

After the ruling, University spokesman Michael Hotchkiss said, “The University looks forward to using the TIGER geo-exchange facility in its commitment to sustainability by meeting campus energy needs without using fossil fuels.”

With the new system in place, Princeton will be on track to achieve net-zero by 2046, according to a November article on the University homepage. By that milestone 300th anniversary, Princeton expects to require roughly one-fifth or one-sixth of the energy it used last year to heat and cool its buildings, even as the campus expands. 

This story was updated to include the adjudication of the lawsuit against the University and the Princeton Planning Board.