Overall Rating Gold - expired
Overall Score 65.52
Liaison Gina Talt
Submission Date Feb. 28, 2018
Executive Letter Download

STARS v2.1

Princeton University
OP-5: Building Energy Consumption

Status Score Responsible Party
Complete 3.59 / 6.00 Thomas Nyquist
Executive Director
Engineering and Campus Energy
"---" indicates that no data was submitted for this field

Figures needed to determine total building energy consumption:
Performance Year Baseline Year
Grid-purchased electricity 287,744 MMBtu 268,700 MMBtu
Electricity from on-site renewables 26,228 MMBtu 0 MMBtu
District steam/hot water (sourced from offsite) 0 MMBtu 0 MMBtu
Energy from all other sources (e.g., natural gas, fuel oil, propane/LPG, district chilled water, coal/coke, biomass) 1,245,901 MMBtu 1,469,670 MMBtu
Total 1,559,873 MMBtu 1,738,370 MMBtu

Start and end dates of the performance year and baseline year (or 3-year periods):
Start Date End Date
Performance Year July 1, 2016 June 30, 2017
Baseline Year July 1, 2005 June 30, 2006

A brief description of when and why the building energy consumption baseline was adopted (e.g. in sustainability plans and policies or in the context of other reporting obligations):

The baseline was adopted because this timeframe was prior to the inception of the University’s Sustainability Plan in 2007-2008.


Gross floor area of building space:
Performance Year Baseline Year
Gross floor area of building space 9,232,747 Gross Square Feet 8,158,600 Gross Square Feet

Source-site ratio for grid-purchased electricity:
3.14

Total building energy consumption per unit of floor area:
Performance Year Baseline Year
Site energy 0.17 MMBtu / GSF 0.21 MMBtu / GSF
Source energy 0.24 MMBtu / GSF 0.28 MMBtu / GSF

Percentage reduction in total building energy consumption (source energy) per unit of floor area from baseline:
16.90

Degree days, performance year (base 65 °F / 18 °C):
Degree days (see help icon above)
Heating degree days 5,018 Degree-Days (°F)
Cooling degree days 1,093 Degree-Days (°F)

Floor area of energy intensive space, performance year:
Floor Area
Laboratory space 3,123,383 Square Feet
Healthcare space 0 Square Feet
Other energy intensive space

EUI-adjusted floor area, performance year:
17,215,942 Gross Square Feet

Building energy consumption (site energy) per unit of EUI-adjusted floor area per degree day, performance year:
14.83 Btu / GSF / Degree-Day (°F)

Documentation (e.g. spreadsheet or utility records) to support the performance year energy consumption figures reported above:
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A brief description of the institution's initiatives to shift individual attitudes and practices in regard to energy efficiency (e.g. outreach and education efforts):

Emails are sent out to students reminding them to unplug and shut off their appliances and lights before they leave campus for extended breaks. Select buildings on campus, such as the Andlinger Center for Energy and the Environment, contain informational signage that explain the energy-efficiency measures in the building.

Additionally, the University partnered with a company called Wattvison to develop a real-time campus energy dashboard called Tiger Energy which continuously tracks and compares residential colleges by their energy usage. Although the platform enables year-round comparisons and includes energy-saving tips, a month-long energy reduction competition among the colleges in the spring is a specific outreach effort to raise awareness about energy-efficient practices while encouraging energy-saving behaviors.


A brief description of energy use standards and controls employed by the institution (e.g. building temperature standards, occupancy and vacancy sensors):

The University uses full distributed digital control (DDC) systems in about 150 buildings on campus, which includes all of the heaviest energy-use buildings. Each building’s spaces have schedules each day to ensure that systems are off for spaces that are unoccupied.

The University uses a variety of occupancy sensor technologies, including dual technology, vacancy sensors, wireless sensors, and light level (i.e. daylight harvesting) sensors.

Digital thermostats, sensors, and radiant panel heating systems adjust heating and cooling temperatures according to various factors, such as occupancy and conservation targets of heating to 68°F in the winter and cooling to 78 °F in the summer. Buildings such as Frick Chemistry have been designed to facilitate cascading air flows which allow laboratories and office areas to be cooled while minimizing use of air conditioning.


A brief description of Light Emitting Diode (LED) lighting and other energy-efficient lighting strategies employed by the institution:

Before the campus-wide LED conversion, the University used LEDs for street lighting, conference rooms, audiovisual rooms, wall washing, and downlighting.


A brief description of passive solar heating, geothermal systems, and related strategies employed by the institution:

Princeton's first ground source heat (“geothermal”) pump system installed in 2003 was one of the most extensive in New Jersey, serving 200 units at Lawrence Apartments. Three other locations, Campus Club, Lakeside Graduate Housing complex, and the new Lewis Center for the Arts complex are also heated and cooled in this way.


A brief description of co-generation employed by the institution, e.g. combined heat and power (CHP):

The electric generator, powered by a General Electric LM-1600 gas turbine that burns natural gas or diesel fuel, is a cogeneration facility. What would normally be wasted exhaust heat from the turbine is recovered to heat water and make steam. Through cogeneration and other waste heat recovery, the efficiency of Princeton’s plant rises to the range of 80 percent vs. 25-40 percent for a typical utility energy plant. The cogeneration plant can generate 15 megawatts of electricity, about equal to Princeton’s average electricity needs on a given day. The Princeton turbine was the first of its kind in the world to earn certification to operate on bio-diesel fuel.


A brief description of the institution's initiatives to replace energy-consuming appliances, equipment and systems with high efficiency alternatives (e.g. building re-commissioning or retrofit programs):

The University has a commitment to replace energy-consuming appliances, equipment, and systems with high-efficiency alternatives when possible. For example, the University has already replaced many of its campus dishwashers and laundry machines with high-efficiency alternatives and is currently replacing most of its campus lighting with LED bulbs. The Princeton energy plant is also being upgraded with more energy-saving technologies such as pumps with variable frequency drivers.


The website URL where information about the programs or initiatives is available:
Additional documentation to support the submission:
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Additional Links:
Tiger Energy: https://tiger-energy.appspot.com/demand/res-colleges

Grid-purchased electricity represents purchased electricity for all areas reported by the University in its CO2 footprint.
Electricity generated from on-site renewables represents energy from the University’s 4.5 MW AC solar PV system. Note that the University accounts for this output as grid-average emissions, not zero CO2, since the University currently sells the SRECs produced by the system.

Since the baseline year (FY 2006), Princeton University's campus square footage has grown by over 1 million square feet. Despite this growth, Princeton's total building energy consumption is nearly the same as it was in FY 2006 due to campus-wide efficiency improvements, which are described further in this section.

The information presented here is self-reported. While AASHE staff review portions of all STARS reports and institutions are welcome to seek additional forms of review, the data in STARS reports are not verified by AASHE. If you believe any of this information is erroneous or inconsistent with credit criteria, please review the process for inquiring about the information reported by an institution or simply email your inquiry to stars@aashe.org.