The Sustainability Action Plan is a guiding document, published by Princeton University in 2019, that sets seven key sustainability goals and metrics for 2046, the University’s 300th anniversary. One of our major goals is to achieve net-zero carbon emissions by 2046. The University plans to achieve this goal in several ways:

1. Improving existing buildling envelopes and constructing new buildings to tighter standards,
2. Converting the campus’ energy systems from natural gas and steam to electric heat pumps, geo-exchange, and district hot water.
3. Utilizing in-house solar arrays and other renewables.
4. Innovative solutions.

Business as usual would see Princeton’s annual emissions rise to 128,000 tons per year by 2046. When completed, the combination of the items listed above will reduce emissions by 96% to 5,000 tons per year. The remaining 4% is anticipated to be reduced by implementing innovative solutions (mentioned above) that will be developed over the next two decades.

Princeton University’s geo-exchange system, when completed, will be among the largest systems in higher education. There are six components to consider when discussing geo-exchange and how our campus infrastructure will be transformed to reach net-zero by 2046.

1. New Energy Facilities - TIGER & CUB - These buildings house the heat pumps and electrical equipment necessary to convert and expand the geo-exchange heating and cooling systems.
2. Geo-Exchange bore fields - More than 2,000 bores, drilled 850 feet into the ground, are essential for heat storage and act as a thermal piggy bank for the system.
3. Thermal distribution piping campus-wide - More than 13 miles of old steam pipes are being replaced with new, better insulated hot water pipes.
4. Building heating & cooling system conversions - Every building on campus will be converted to the new hot water heating system. New buildings will not use steam except to meet specialized research needs. 
5. Solar Expansion - We’ve more than doubled our previous solar photovoltaic (PV) generating capacity from about 5.5% to 19% of campus electric energy use.
6. Building Renovations to increase energy efficiency - We are performing renovations on many of our historic buildings to reduce energy consumption, such as new windows, insulation, and lighting sensors. 

The geo-exchange and hot water conversion projects are a major component to achieving net-zero carbon emissions. When completed, the efforts will reduce campus emissions by 96%. The remaining 4% is anticipated to be reduced by implementing innovative solutions that will be developed over the next two decades.

Princeton University’s geo-exchange system will have little or no measurable impact on the local environment. The closed-looped geo-exchange piping means that the water never contacts the ground itself. The bedrock beneath campus, typically stable at 57 degrees Fahrenheit, will rise to 85 degrees Fahrenheit by late summer and will drop to 38 degrees Fahrenheit in late winter. The variation in temperature will have no impact on local plant and animal life. All geo-exchange bores and associated piping are located below the frost line and they have less influence on the ground surface temperature than the outside air temperature. The boreholes will not affect groundwater quality. 

Mass Timber is a strong building material composed of laminated, glued, or doweled wood. Mass Timber, considering extraction, manufacturing, and transport, has a lower carbon footprint than similar quantities of concrete and steel. Because of this, Princeton has elected to utilize mass timber where it is most appropriate, with concrete and steel to supplement where needed. When choosing materials for building, the University considers cost, vibration, use of space to ensure projects have the lowest carbon footprint possible. 

The new buildings utilizing mass timber include:

• Frist Health Center
• Class of 1986 Health and Wellness Center
• Princeton University Art Museum
• Hobson College
• ES & SEAS
• Schmidt Hall

Congratulations on taking the first and most important step towards building a sustainable future - deciding to get involved. The first thing to do is sign up for the Office of Sustainability’s monthly newsletter, emailed the last Tuesday of each month, where you will receive the latest sustainability news and opportunities to take action on campus. 

• Does your department/student organization host events with food?
  • If yes, consider taking advantage of the Office of Sustainability’s Compost Support Program. 
• Want to hear more about Office of Sustainability projects and progress toward Sustainability Action Plan goals?
  • Attend a Princeton Sustainability Committee (PSC) monthly meeting. 
• Does your department have a Sustainability Staff Ambassador?
  • Learn more about our Staff Ambassador program, and get access to trainings, workshops, sustainability tours, and more for you and your work group.