The campus of the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) has a very different look this winter than last year. Construction fences went up around PPPL’s main building, the Lyman Spitzer Building, as machines dug holes 500 feet into the ground for geothermal wells that will help heat and cool PPPL’s first new building in decades — the Princeton Plasma Innovation Center (PPIC). 

“This has been a fantastic launch to the project,” said Tim Meyer, chief operating officer and deputy director for operations. “It’s an exciting time, and we’re looking forward to PPIC’s completion in 2027.”
 

Geothermal wells will provide energy-efficient heating and cooling

Work on the geothermal wells began in November 2024 and concluded at the end of February 2025. Contractors first used heavy equipment to dig the wells, which are six inches in diameter. Next, they installed U-bend piping and injected the holes with a special grout to protect a set of pipes within the wall. The grout also helps conduct the heat between the piping and the ground. Each of the wells, around 70 in total, will be connected through underground pipes to become part of a geoexchange system. The system will provide about two-thirds of the heating and cooling for the new building. 

The geoexchange system has been described as a thermal “piggybank.” “You have these bores with the tubing going in and out, then the earth itself acts as a heat sink in the summer and a heat source in the winter,” said Michael Starkey, an energy manager in PPPL’s Facilities & Site Services Department. “It pulls heat out of the building in the summer, injecting it into the ground. In the winter, you’re able to pull the heat out of the ground.” 

VIDEO: Preparing for PPIC by digging geothermal wells

The PPIC building also has numerous other unique features that will help reduce building operational costs. These features include improved and natural lighting, new mechanical systems, passive shading to cool the building and electric boilers for hot water.

Princeton University, which operates PPPL on behalf of the DOE, has invested millions of dollars to install geoexchange systems in new construction projects throughout its main campus. 

The next major phase of the project will be the construction of a concrete foundation in the spring of 2025. Structural steel work will begin in the summer of 2025, and walls will be erected in the late fall of 2025. Construction of the exterior building will be largely complete by spring 2026.
 

Building demolition is complete

At the end of August 2024, large excavators demolished the Theory Wing, which was built in 1978 and home to many well-known theoretical researchers. Most of the adjoining Administration Wing, which dates to 1959, was also demolished. The demolition is complete with the exception of some heating, ventilation and air conditioning (HVAC) equipment. 

The demolition and other site preparations were made possible by $10 million from Princeton University. 

The Laboratory broke ground on the $109.7 million building in May 2024, and construction is expected to conclude in 2027. The building will provide laboratory space and offices for many of PPPL’s researchers and support staff. The Lab has expanded its mission and expertise in plasma beyond developing fusion energy by contributing to fields such as microelectronics and quantum sensors and devices.

“It’s awesome,” said Steve Langish, the project director. “It’s very exciting to see the progress on the project. PPIC has a good safety record, and we’re right on schedule.”

PPIC is envisioned as an iconic building that will become the “town center” of PPPL’s campus. The 68,000-square-foot U-shaped building designed by the SmithGroup has three axes: the first floor of the north wing is a collaborative wing where visitors will enter. Above it are the second and third floors of the north wing, which are set at an angle to overlap the first floor and will be dedicated mostly to office space for around 170 staff members. The laboratory wing to the south has 10 medium-bay laboratories and 13 small-bay laboratories on the ground floor. 

The laboratory wing connector and the north wing intersect at the café, which connects with PPPL’s main office building, the Lyman Spitzer Building. 

Infrastructure project moves forward

Meanwhile, PPPL is also moving forward with the multimillion-dollar Critical Infrastructure Recovery and Renewal (CIRR) project, aimed at renewing the Laboratory’s core utilities on its campus to make those systems more reliable and efficient and support its growing research programs. 

 The project includes upgrading infrastructure for the following:

• Chilled Water Systems: Upgrading the water system, which is used for the HVAC systems and to cool the National Spherical Torus Experiment-Upgrade and other experiments.
   
• Communications Distribution Network: Upgrading the system to allow high-speed internet.
   
• Electrical Distribution and Standby Power: Upgrading the main electrical yard, distribution system and standby power, along with installing additional capacity as needed to provide reliable systems that can better support experiments.
   
• HVAC Systems: Replace heating and air conditioning systems that are 40-60 years old with more cost-efficient, reliable and resilient systems.
   
• Underground Distribution Systems: Replace underground pipes and electrical wires across the site and upgrade the storm-retention basin.
   

The CIRR project will be 90% designed by March 2025. PPPL is seeking the DOE’s approval at that time to purchase long-lead equipment before beginning construction in the spring of 2025. The CIRR upgrades will likely be finished in 2028.