University power plant operates close to maximum efficiency

Every time a University student takes a shower, enjoys air conditioning in the library or makes instant noodles, it helps make one of the most efficient power plants in the United States even more efficient. The University cogeneration plant, though small in size, plays a critical role in the life of every undergraduate. Located below the tennis courts and run solely by the University, the plant generates most of the electrical power used on campus.

The University's use of power is strikingly more efficient than that of the surrounding area. The Mercer Generating Station, which serves the Princeton area, was cited in a recent Environmental Protection Agency report as the second most polluting power source out of 616 in New Jersey.

Edward Borer, the University's Manager of Mechanical Systems, explained that while the Mercer plant operates at 25-30 percent efficiency, at the University's plant, "we recover most of the waste heat to heat dormitories in winter and warm water."

Borer explained that this type of plant is called a "cogeneration" plant because it simultaneously produces both heat and power.

"Essentially from one fuel input, we are doing two different things. The Mercer plant is probably just generating electricity," he said.

"It's not that these utilities are capriciously wasting energy," Borer said, "they just don't have customers for the low-grade waste heat."

Mercer burns coal or natural gas to make steam, which is used to turn turbines and make electricity, Borer said.

Relative to the Mercer plant, "our plant is closer to 80 percent efficiency in terms of the fuel we purchase versus energy delivered" he said. "We are making correspondingly less environmental impact in both pollutants and thermal waste."

"Because of the fuel efficiency of this new plant, we are able to make electricity more cheaply than we can buy it," he said.

Even in summer, the University puts the excess heat from its plant to good use.

"In the summer, we use the heat to make steam to drive steam turbines to drive chillers that we use to air condition the campus," Borer said.

"The University's plant is as environmentally friendly as you can get," said electrical engineering professor Sigurd Wagner, who teaches a freshman seminar entitled "How Cities Work."

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The University needed to build its own plant because scientific laboratories require extremely dependable, uninterrupted electricity, Wagner explained.

Having decided to build a plant, the administration wanted to make sure that it would be as environmentally sound as possible, he said.

Wagner added that the University sells power to the surrounding community at times of the day when demand on campus is low, such as late at night. Conversely, he said, the University buys power to supplement the output of its plant at peak times, such as the middle of the day.