PERC Environmental Audit - Chapter 5 Energy Use

The use of energy at Princeton University has steadily increased throughout this century due to the addition of modern energy-intensive facilities and the growth of the campus population. The university, however, has had a responsible track record with regard to the implementation of energy conservation practices. This has been due for the most part to the economic benefits of conserving energy. Energy conservation also results in a decreased consumption of non-renewable resources and a decrease in the generation of air pollution. Future efforts at energy conservation will continue to provide cost savings for the university as well as lessen the universityís impact on the environment. These efforts should be guided by taking a pro-active approach to adopting energy-conserving policies or technologies whenever feasible and educating the campus community about the simple steps people can take to help the university conserve energy and money. More specific recommendations include 1) placing all new buildings and certain existing buildings on the Central Supervisory Control System (CSCS), including lighting controls on the CSCS, 3) installing compact fluorescent light bulbs in dormitory hallways and rooms, purchasing energy-efficient computers and upgrading currently-used computers to higher efficiency levels, 4) installing motion detectors in strategic areas such as campus bathrooms, 5) improving heating and insulation of dorm rooms through better windows and more careful regulation of overheating, and 6) initiating a student energy conservation competition.

The production and distribution of utilities at Princeton University began in 1876 with the installment of boilers in the basement of old Dickinson Hall as the basis of a heating system for nearby buildings. In 1903, a power plant was built to provide electricity to the campus and exhaust steam for heating academic buildings, although dormitories were still being heated through the use of coal-burning fireplaces. In 1923 a new power plant was built at the southern edge of campus to meet growing electricity and steam needs, and in the late 1950ís a substation was built on Charlton Street to purchase supplemental power from PSE&G. In the early 1960ís, air conditioning was introduced to academic and administrative buildings via a central refrigeration plant and a chilled water distribution system. By 1967, in anticipation of stricter state air pollution laws, the university switched from coal to oil and gas usage.

The energy crisis of the 1970ís woke the nation to an interest in and utilization of energy conservation practices. Princeton University was not exempt from the effects of the oil shortage. In 1973, the university was unable to purchase oil due to the rationing of fuel. As energy costs became an increasingly large portion of the Universityís operating budget and as construction of buildings on campus expanded, the administration sought to institute a cost-savings program of energy management. The first steps were the adoption of a winter heating policy of 65°F and a summer cooling policy of 78°F, installation of time clocks on mechanical systems, removal of lamps, and overall improved preventative maintenance. The next actions improved the utility distribution systems; projects during this period included the installation of a secondary pumping system in campus buildings connected to the chilled water plant, the addition of attic insulation, and additional metering of utilities. More capital intensive projects were also pursued, including the installation of a heat exchanger in the chilled water plant to provide ìfree coolingî in the winter and the installation of an energy management and control system.

After conducting comprehensive feasibility studies of the campus and evaluations of the major vendors of energy management and control systems, the university signed a contract in August 1977 with Hamilton Test Systems. The energy management and control system (Central Supervisory Control System or CSCS), sometimes called a central processing system, consists of a central computer located in MacMillan Building linked to remote buildings by means of direct burial cable, modems, and telephone lines. In the 1980ís the cost of processing dropped and a remote microprocessor data multiplexer (RMDM) was installed in each building. RMDMs transmit temperature readings, status of mechanical equipment, and steam, chilled water, and electrical meter readings to the central processing computer. The central computer wields control over the starting and stopping of mechanical equipment, time of day scheduling, and the optimal start time calculations. Thus, based on criteria entered into the computer, the system can calculate, for example, the appropriate time to start air conditioning systems. This way, if people are arriving to work at 8 a.m., the CSCS will turn on the air conditioning a few hours beforehand so the buildings are cool when people arrive. In a similar fashion, the CSCS will heat a space using the least amount of energy possible. At any point the operator may take manual control of the system -- to start or stop equipment, establish a reference temperature, etc. These features are useful in identifying potential problems with the equipment. In addition to energy management, the CSCS has an added bonus of checking on maintenance; for example, an alarm goes off when filters need to be changed. Also, there is a reduced demand on utilities; the university avoided purchasing a new chiller due to the efficiency introduced by the CSCS.

At present 70 to 75 buildings are on the CSCS system out of the approximately 278 academic, administrative, athletic, dormitory, and graduate housing buildings on the main campus of the University. (The Forrestal Campus is handled separately.) Some buildings may have more than one RMDM; the relatively new Bowen Hall has three. Buildings were selected to be put on the CSCS system on the basis of energy usage. Most academic and administrative buildings are on the system, as well as those most recently renovated. Only one dormitory, Forbes College, is presently on the system. It was decided not to include the vast majority of the dormitories on the CSCS system because the potential savings would be extremely limited.

The Gothic architecture of several dormitories, while quaint and picturesque, is not energy efficient. Many buildings are without storm windows and have poor insulation. Further problems result from the inefficient heating system. Heat is delivered to university dorms and offices by means of steam or hot water systems. Because a minimum temperature of 68°F must be maintained during the winter in the coldest portion of the building, as stipulated by state policy, occupants of other portions of the dormitory building often complain of overheating. This inequality of room temperatures results in both an uncomfortable environment and wasted energy. In addition, some dorms are unnecessarily heated during winter breaks, despite the fact that they are unoccupied. The steam is shut off to the heating system in April.

In the winter the university burns oil and gas for fuel. Princeton University is an ìinterruptible customer,î meaning that at notice from PSE&G, the university will switch to gas, which is purchased on the spot market by the universityís brokers. Departments pay their own energy bills, and conservation programs are funded by the Facilities Department budget. Table 4.1 lists campus energy consumption statistics for the last fiscal year:

Total Steam Consumed	830,083,650 lbs
Total Chilled Water Produced	19,147,899 ton/hr
Total Electric Energy Used	92,288,000 kWh
Steam Sold to Chilled Water Plant	181,658,600 lbs
Steam Sold to Turbine Room	0
Electricity to Boiler House	2,195,200 kWh
Electricity to Chilled Water Plant	8,604,720 kWh

The general trend has been one of fairly steady increases with sharper increases associated with the additions of new buildings such as Bowen Hall, Marx Hall, and Schultz Laboratory. It is difficult to gauge the effectiveness of a particular energy conservation project based on meter readings of overall electricity usage, since there are only two reliable meters on campus. Less accurate meter readings are available for individual buildings of campus. Spreadsheets of these meter readings are available upon request; contact PERC for further details.

Most conservation projects require a payback period of four years or better, meaning that the savings generated by implementation of the project must equal the cost of implementation after a maximum of four years. One such conservation measure that has been implemented is the CSCS. It cost $3,000,000 to install and has a savings of $1,000,000 per annum, a three year payback.

The campus electricity bill totaled approximately $6.5 million for the 1994 fiscal year. An electrical energy conservation program begun in 1990 has yielded savings of about $400,000 per year. Most of the effort has been focused on upgrading old lighting systems. About 1500 of 3000 incandescent lamps in exit signs have been replaced with 25-year LEDs, yielding savings of about 1335 man-hours of labor per year in avoided replacement time in addition to electricity savings. Replacement of over 5000 incandescent lamps (1000-hour lifetime) with compact fluorescent lamps (10,000-hour lifetime) has cut lighting demand and saved in maintenance and cooling costs. Another significant energy-saving measure has been the installation of motion and daylight sensors in classrooms, auditoriums, and hallways (e.g. Fine Hall and the Engineering Quadrangle). These sensors, which automatically shut off the lights if they do not perceive motion for a designated period of time, result in an approximate 50% reduction in classroom lighting and 20-25% reduction in hallway lighting demands. These electricity conservation measures have a significant effect on lessening the environmental impact of the university. Specifically, the amount of CO2 for which the university is responsible was reduced by 2200 tons/yr., the amount of SO2 by 15,000 kg/yr., and the amount of NOx by 5700 kg/yr.

Princeton has signed on to the voluntary EPA Green Lights Program as a Green Lights Partner as of July 1, 1994. The Green Lights Program seeks to increase awareness about the possibilities of increasing lighting efficiency without sacrificing the quality of light. As a Partner, the university will perform lighting surveys in 100% of eligible buildings and upgrade 90% of eligible square footage, where profitable, within five years. Also, all new construction or renovation projects require energy-efficient lighting to meet university conservation requirements.

Projects for the near future include continuation of retrofitting of exit signs and replacement of incandescent lamps with compact fluorescents, upgrades to more efficient fluorescent lighting, and devices to shut off computer monitors when they are not in use. A PSE&G Demand Side Management rebate program is being considered. This program would offer a rebate to the university if it could meet the project goal of a 200 kW (about 1%) reduction in demand.

Cogeneration is the process of producing electric and thermal power simultaneously. In the mid-80ís, the Facilities Department pursued options for the replacement of its aging central steam plant. In 1985, the university considered the construction of a coal-fired fluidized boiler which seemed economically attractive. In 1987 the plan was dropped in favor of a gas-turbine cogeneration plant. It was decided the plant would incorporate a natural gas-fired gas turbine, which would generate electricity, and a heat recovery boiler, which would recapture waste heat from the turbine to generate steam. Facilities made a presentation to the Building and Grounds Committee for the Board of Trustees in December 1991. In February 1992 a request was submitted for the authorization of funds, and the Trustees approved funds of $1.5 million for the cogeneration project. In the spring of 1992, bids for the gas turbine package were received and reviewed; European Gas Turbines (EGT) was selected to supply the equipment. The EGT proposal was used to prepare an air emissions permit application to the New Jersey Department of Environmental Protection (NJDEP). In December 1993, the NJDEP informed Facilities that the project met their criteria. In early 1994, the Facilities group briefed the Princeton Regional Planning Board on the cogeneration plant. Facilities should break ground on the project shortly and expects to complete the plant, which will be located by the chilled water plant, by the summer of 1996.

The University of Arizona is a small ìcityî of 50,000 with a utility bill of over $15 million a year. One million dollars have been saved annually since the school adopted conservation projects three years ago, despite an increase in electricity use by 15.8% and campus growth by 17.7% over the past five years. Its participation in Tucson Electric Powerís rebate program returned over $87,000 in 1993 following the installation of energy-saving light ballasts and updated fluorescent lights. The campusís computerized energy management system shuts down many air handlers on weekends and holidays ($100,000 was saved during a ten-day holiday campus shutdown in December of 1993). Many rooms are also installed with movement-sensitive light switches that automatically shut off after fifteen minutes of no movement. The University of Arizonaís Student Union and Residence Life also encourage energy conservation through separate metering. A contest held by Residence Life rewarded the most energy-conserving hall a television set and thus created an added incentive for residence halls to reduce energy use.

The University of Michigan Ann Arbor Campus has a student, faculty, and staff population of over 50,000 as well. Its central power plant (CPP) produces half the energy needed by the 205 major buildings in addition to the 221 buildings designed for family housing. The cogeneration system runs on natural gas, which is a lot cleaner than the coal burners used at other universities such as Michigan State and Purdue University. Spending for FY 1990-91 totaled $52,803,807.33 for 22,377,175 square feet of space. Efforts to conserve energy have worked through ECAP, the Energy Cost Avoidance Project organized by the school. Plans include baseline models based on outdoor air temperatures, nighttime ventilation, daylight photosensors, and possibly an integrated lighting and air-conditioning control system. The utilities department is currently working on updating pneumatic temperature controls, laboratory fume hoods, separate energy managers of larger, more inefficient buildings, and carbon dioxide sensors.

Most schools have a cogeneration plant and computerized energy management system in addition to other energy conservation practices. Princeton University has implemented a fair amount of laudable energy-saving measures, but there are more steps that could be taken before it will be considered to be a model of sound energy use.

The CSCS system is extremely well managed and regulated by the Universityís Facilities Department. The only specific recommendation that applies here is to put more buildings on line. Presently, most of the academic buildings on campus use the system, but few of the dorms employ CSCS. The more modern dormitories, such as Brown, Dod, Edwards, and all of Wilson and Butler Colleges should be put on line to tackle the problem of heating inequality and inefficiency. And naturally, all future buildings should be automatically placed on the CSCS system following completion. It might also be cost-effective, beyond simply regulating the provision of heat, to add simple measures such as storm windows and insulation to currently-existing buildings in order to reduce heating requirements. A cost-benefit analysis of such a measure remains to be performed.

Lighting (i.e., electricity) should also be included on the CSCS system. Some buildings, such as Nassau Hall and New South, are unoccupied at night, yet the lights are often left on. It seems that such administrative buildings, which are used on a regular work-day schedule, would not necessarily need motion detectors to regulate their lighting. Simply ensuring that these lights are turned off, whether by central computer control or Tiger Patrol, after employees have gone home for the day would represent a significant cost savings for the university.

The university has been replacing old showerheads with low-flow models as the old ones break. Full replacement should take place immediately, as there is no question that low-flow showerheads pay for themselves in avoided water heating costs in less than a year and usually less than six months.

5.4 Install compact fluorescent light bulbs in dormitory hallways and rooms.

As mentioned before, the amounts of energy consumed and, consequently, the pollution produced by incandescent lighting are much greater than that associated with fluorescent lighting by a factor of three to four. The same amount of light can be provided by a compact fluorescent for 75% less energy than would be required through the use of an incandescent. Even though a compact fluorescent bulb has a higher initial cost, it lasts about ten times longer than an incandescent bulb, so that incandescent bulbs cost more over an equivalent lifetime; this is especially true when one factors in the avoided costs associated with installation labor and maintenance. Thus, it makes financial and environmental sense not only to retrofit the lighting in public corridors of dormitory buildings to compact fluorescents, but also to address the manner of lighting inside dorm rooms.

The lighting of dormitory rooms has been identified as a prime area for conservation measures to be implemented. Students currently purchase 300 or 500 watt halogen lamps to compensate for the poor dorm room lighting. This has caused a sharp increase in dorm energy use. The university should urge students to switch from halogen use to compact fluorescents, or at least emphasizing task lighting over the inclination to light an entire room. This problem is primarily an issue of student awareness; thus, the university should investigate the environmentally-friendly lighting options that are readily available in the area and make the information available to first-year students. The Student Lamp Agency, which currently supplies halogen lamps exclusively based upon perceived student demands, would be a valuable ally in this endeavor.

As a preliminary step, Princeton Environmental Action (PEA) has been contacted about conducting an extensive student room lighting survey to get an accurate assessment of the extent of halogen use in the dormitories and so that an estimate can be made of the potential energy savings involved in eliminating the use of halogen lamps. The basic questions would ask the occupancy of each room and the number and wattage of halogen lamps compared to the number and wattage of incandescent or fluorescent lamps in the room. An informal survey of this nature was conducted under the auspices of the Ad Hoc Environmental Committee two years ago, the results of which confirmed suspicions about the general extent of halogen use and identified this area as a prime target for reform. This survey could also be used to investigate student opinion of dorm room over- and under-heating in the winter.

The lights in dormitory bathrooms are rarely, if ever, shut off. In several buildings (e.g., Pyne and 1903 Halls) light switches do not even exist in the bathrooms. Motion and daylight sensors, like those already installed in E-Quad classrooms and hallways, could be used to reduce this waste of electricity. A simpler and cheaper, if less certain, action would be to invest in small ìturn off lights when not in useî signs to be displayed prominently over bathroom light switches.

Computers, like lighting, represent a large portion of campus energy consumption. A standard computer monitor uses at least as much energy as a 100 watt light. Thus, the devices being considered to shut off monitors of idle cluster computers will likely result in substantial savings, both in electricity and in cluster cooling, since the unused monitors will not be producing excess heat.

In the future, the EPAís Energy Star program computers should be strongly considered when purchasing new equipment and replacements for old equipment, since Energy Star computers power down to under 30 watts when idle. A recent study estimated there to be at least 7000 computers on campus, including those belonging to faculty and staff and students as well as the 500 or so computers found in CIT and other computer clusters, which typically remain on 24 hours a day. Table 4.2 demonstrates the savings that can be made through the use of Energy Star systems. In performing these calculations, the average private computer was estimated to be on for 8 hours a day but actually used for only 4 hours a day, and public computers were assumed to be on 24 hours a day and not used for 16 of those hours. Using the assumption that a standard computer runs at 150 watts, at 8 cents/kWh, we can arrive at the direct electricity savings presented below (reduced cooling costs are not considered here):

	Cost/yr. (1 computer)	Savings/yr. (1 computer)	Savings/yr. (7000 computers)
Private computer, on 8 hours per day	$35	--	--
Energy Star computer, on 8 hrs, asleep 4 hrs	$21	$14	$98,000
Public computer, on 24 hours per day	$105	--	--
Energy Star computer, on 24 hrs, asleep 16 hrs	$49	$56	$28,000 (500 computers)

Table 4.2 Estimated savings generated through the use of Energy Star computer systems.

Obviously, the computer clusters operated by CIT and University departments will be much more easily converted to these energy-saving computers than privately-owned machines. But since many students purchase their computers through CITís Microcomputer Distribution Center, the university still has a direct avenue of influence there.

A campus wide survey could be done to see which particular dorm rooms are being over-heated and which are being under-heated, to see where attention needs to be focused. This survey could be combined with the dorm lighting survey, for convenience. If it is found, as we suspect, that every dormitory is overheated, the heat supply to the dorms should be decreased accordingly.

Since there are only two reliable energy meters on campus, one for portions of the university west of Elm Drive and one for the east half, any energy conservation competition between residential colleges or individual dormitories may be difficult to judge quantitatively. The cost of installing accurate electricity use metering devices on individual buildings has been quoted as quite prohibitive. Money would be better spent on retrofits and the other energy-saving measures mentioned above. However, such a competition effort would be valuable in both improving student awareness of campus energy issues and displaying support for sound campus environmental practices. The effort would not be monetarily expensive; however, it would require strong degrees of organization and commitment from concerned university members, students, faculty, or administrators.

The concept of passive solar design is to design buildings so they take maximum advantage of sunlight for heating and lighting and do the best possible job of avoiding overheating during the summer. Passive solar design should seriously be taken into account for future construction, since it will reduce energy bills and improve the indoor environment in almost any building. The features to look for as signs of a design that will work with the environment include southern exposure and glazing, overhangs, daylighting, high insulation levels, and good ventilation systems. For more details, please refer to the New Facilities chapter of this audit.

This material may be used for educational and non-profit use. Commercial use of this information is prohibited without written consent. Copyright © 1995, Princeton Environmental Reform Committee, Princeton University.

Princeton Environmental Reform Committee (PERC) Environmental Audit of Princeton University

Chapter 5 - Energy Use