Progress Towards Reducing Campus Carbon Emissions: Update from ED Thomas Nyquist

An update from Executive Director, Engineering and Campus Energy Thomas Nyquist:

Humanity is in the process of overheating earth much like a greenhouse by using our thin atmosphere as a dumping ground for 51 billion metric tons annually of carbon dioxide and other greenhouse gases.  Storms will get worse, droughts will increase, and sea levels will rise.

Princeton University is actively engaged in many areas of academic research and advocacy to mitigate climate change.  On the administrative side of the university, we need to reduce our campus emissions.

In 2015, at the start of our campus master plan, a committee of faculty members and Facilities staff recommended that the campus be net carbon neutral by 2046. They stipulated that the university cannot use offsets to achieve this goal and we cannot wait for the next generation to act.   Their recommendation was based upon scientific research that showed that global emissions of greenhouse gases must be reduced starting now and all global emissions must be eliminated by 2050.

This campus emissions recommendation was the most significant input into our analysis for our next generation heating and cooling plant.  The university’s existing steam cogeneration plant burns natural gas and fuel oil and had no hope of meeting the carbon target.  Additionally, the old plant did not have extra heating and cooling capacity to handle the future loads created by the university’s current large construction program.  Lastly, portions of our underground steam system date to before World War I and need replacement.  You may have noted steam plumes coming from the underground steam system across campus.  It’s time to start replacing these steam pipes or switching to a new system based upon heating hot water.

Our new heating/cooling system addresses all these concerns.  The new plant consists of heat pumps that provide heat to a new campus wide underground hot water distribution system for our buildings.  Heat pumps concentrate heat.  They work just like your refrigerator.  When you put warm leftovers in the refrigerator, they heat up the air inside the refrigerator from 38 to approximately 42 degrees.  To keep the refrigerator cold, the refrigerator then pumps this heat out of the refrigerator and into the room air.  Thus, warming the kitchen and cooling the air and leftovers inside the refrigerator.  We are doing the same thing with the new plant heat pumps.  The “heat source” is the ground.  There are 1000 new 850-foot deep geoexchange bores under campus with water pipes in each hole.  Water is circulated down these pipes where it heats up to about 58 F.  This water flows into the heat pump and provides the source of the low temperature heat.  The heat pump then concentrates this heat and produces 145-degree hot water for campus heating.  No fossil fuels are burned in the process, and it is up to 4 times more efficient than burning gas.  The heat pumps reduce the ground temperature.  In the summer, we reverse the process and pump heat down into the ground. 

The heat pump motors will be partially powered by carbon free electricity from our campus solar panels with the remaining power coming from cogen or PSEG. In the future, we will use more renewable power as it comes online.  The university’s campus carbon footprint will be greatly reduced with our new geoexchange heat pump system and ultimately carbon free power.

We now have five geoexchange heat pump systems on campus.  The first was installed in 2004 to serve the buildings in the Lawrence Apartments Complex.  The other small systems are at Lakeside Apartments and LCA.  In October, we started producing heating hot water from our new Tiger Plant located near the Stadium Parking garage.  Next month, we will be operating a new CUB heating plant on the Meadows campus.  These new energy plants and the rest of our carbon reduction program show leadership in the very important struggle to minimize global warming.

This hot water conversion program was made possible by solid support from the trustees, the senior administration, faculty, and by Facilities planners, project and program managers in OCP, Engineering and Plant staff, Communications, FF&S, and Operations. I want to take this opportunity to THANK everyone involved in this very significant endeavor.