When Princeton released its first comprehensive Sustainability Plan in 2008, the University outlined quantifiable targets for reducing its use of energy and other resources by 2020. A new report released last month cites several improvements, including reductions in water use and carbon-dioxide emissions.

“We are showing measurable progress toward [the 2020] goals, and in some cases, we’re exceeding our own expectations of what we thought we could achieve,” said Shana Weber, manager of the Office of Sustainability.  

In annual dormitory water use, Princeton has seen a 24 percent decrease since 2006, the baseline year for the ­sustainability office’s 2020 goal of a 25 percent reduction. Weber said that relatively inexpensive retrofits — dual-flush toilets and low-flow showerheads and sink aerators — were responsible for the change. With the residential improvements nearing their goal ahead of schedule, the University has begun making similar changes in other high-use areas like the showers at athletics and fitness facilities.

Princeton’s carbon-dioxide emissions declined for the second consecutive year, dropping by about 1.5 percent from fiscal year 2009. Electricity usage has increased in the last two years, but the University has been able to provide energy, heat, and air-conditioning with lower emissions by implementing new technologies, including a system that recovers heat from the steam exhaust at the campus cogeneration plant.  

Through 2017, Princeton plans to spend $45 million on measures aimed at reducing campus energy use by 25 percent. One idea under consideration is a solar collector field on some of the University’s land in West Windsor. Specific projects are outlined in a new “energy master plan.”  

To reach its goal of reducing emissions to 1990 levels by 2020, the University will need to continue its rate of reduction for the next 10 years — a significant challenge as the campus energy grid adds facilities such as the new Frick Chemistry Laboratory and the forthcoming building for neuroscience and psychology. But after a decade of increasing emissions, Weber said, officials are “starting to feel comfortable that we’re actually turning the corner.”

Many of Princeton’s sustainability efforts conserve resources through automation. For example, common areas in new buildings are equipped with sensors that measure carbon dioxide in the air and activate ventilation based on the number of people in the room. Other initiatives rely on individual choices, like the “print less” program, which cut paper use by 34 tons in 2009-10, and recycling of household waste, which has increased from 38 percent to 43 percent in the last three years.  

Beyond campus, Princeton has earned high marks for its sustainability efforts, most recently from the Sustainable Endowments Institute, which gave the University an overall grade of A- on its College Sustainability Report Card, released in late October. Princeton was one of 52 schools in the United States and Canada to reach the A range.

To read the full sustainability report, visit www.princeton.edu/reports/2010/sustainability