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Campus Energy


In recent years long-standing energy conservation efforts at Princeton have intensified in response to the global warming challenge. The University is committed to measurable greenhouse gas reduction actions that will meaningfully reduce campus emissions. This goal applies to the central plant facility and purchased power as well as to increasing the efficiency of new construction and renovated facilities. The University will achieve this goal through local verifiable action and no purchase of offsets. 

Figure 1: Greenhouse Gas Emissions Projections
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The University's goal is to reduce carbon dioxide emissions to 1990 levels (95,000 metric tons) by 2020 -- 16 percent or 19,000 metric tons less than the amount it emitted in 2007. If it took no action to reduce emissions, the University would produce 176,000 metric tons of carbon dioxide by 2020 driven by its expanding operations. Click to enlarge.
Figure 2: Greenhouse Gas Emissions History
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For the first time since the cogeneration plant began operating in 1996, on-campus emissions have decreased. This has occurred even with an expansion of nearly 164,000 square feet between July 2008 and July 2009. Click to enlarge.

Goal & Progress

Goal: Reduce greenhouse gas emissions to 1990 levels by 2020 (Figure 1).


  • Even with square footage expansion, emissions are leveling off (Figure 2). While the decrease from July 2008 to July 2009 has been modest (nearly 1 percent), this is a significant step in the right direction, considering that the University added nearly 164,000 square feet to its physical plant during the same time period. Princeton must work to continue this momentum and decrease emissions by 16 percent below 2007 levels. (See update.)
  • Due to conservation efforts, electricity usage by the campus increased only by 2.6 percent from 2007 to 2009, even with the addition of Sherrerd Hall, Lewis Library and Roberts Stadium; the University continues to strive to reduce usage through conservation efforts in the face of a growing physical plant.
  • No purchases of offsets or renewable energy credits have been made or are planned; Princeton is aiming to achieve its emissions reduction goals solely through local verifiable action.
  • The University is investing more than $40 million in the next 10 years to reduce overall utility usage on campus by at least 25 percent, in part by improving the efficiency of the high-performance central cogeneration plant and the buildings it serves (which account for approximately 85 percent of the University's emissions). These initiatives will be coordinated through the development of an Energy Master Plan.
  • In September 2009, a direct heat exchanger was installed in the plant to capture waste heat. This is expected to improve overall plant efficiency between 8 and 10 percent from a baseline of roughly 75 percent. It should avoid more than 4,500 metric tons of CO2 produced each year, reducing campus emissions by more than 3.5 percent.
  • The University has identified 70 percent of the operational strategies needed to achieve its 2020 goal.
  • Princeton has acquired the first permit to run biodiesel in General Electric's LM1600 gas turbine, which is located in the cogeneration plant and provides heat and electricity to the campus.

What's Next

  • Expand light emitting diode (LED) office and outdoor lighting, moving from pilot to specific project implementation.
  • Continue to install motion sensors integrated with lighting as well as room heating and cooling systems.
  • Investigate the feasibility of pursuing local wind power as part of the University's renewable energy portfolio.
  • Identify the remaining 30 percent of the operational strategies needed to achieve the 2020 goal, largely through behavioral change and advancements in technology.
  • Draft a campus Energy Master Plan to provide a coordinated effort to improve the efficiency of the cogeneration plant and the buildings it serves in order to reduce overall utility usage on campus by at least 25 percent.

Well drills
Beneath the Springdale Golf Course driving range lies a treasure that is saving graduate students who live in the nearby Lawrence Apartments more than half on their energy bills. Read more about geothermal wells.

"Our firm designed a ground coupled heat pump system for the new Lawrence Apartments, the first geothermal project undertaken by the University. The system has been in operation for five years and performance has exceeded that predicted in our simulations of the buildings. Based on our positive experience with this design, we have been advocating incorporation of geothermal systems in many of our other projects."
Ira Guterman, Princeton Engineering Group, LLC

Awards & Achievements

The University's cogeneration plant received a U.S. EPA Energy Star CHP (Combined Heat and Power) Award in 2007 for efforts to reduce pollution and improve energy efficiency. In 2009, Princeton received a letter from the CHP Partnership recognizing the University for a project in which equipment was added to the plant to improve the overall system energy efficiency and other measures. "[These] projects serve as examples of leadership in energy management and efficient energy production," the letter stated.

The University recently partnered with Princeton Borough and Township to modify the local exterior lighting ordinance to include the option of installing energy-saving LED lights.

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ֶListen to a student-produced podcast on innovations at the Princeton power facility.

Energy upgrades and innovations
have been implemented across campus. Innovation examples include: using geothermal technology at Lawrence Apartments and Campus Club; installing photovoltaics at the Research Collections and Preservation Consortium (ReCAP) building on the Forrestal Campus and on the new Chemistry Building; and generating more efficient energy with new backpressure turbines on steam lines, the equivalent of heating, cooling and electrifying nine dorms the size of the 93,356-gross-square-foot Little Hall.

Little Hall
Little Hall