Beginning today, a new, environmentally-friendly Cogeneration (Co-Gen) system within the University’s Central Power Plant will allow the plant to produce electricity for the first time. Although the plant’s three boilers supplied and distributed compressed steam for heating and chilled water for air conditioning purposes, the $3.5 million project will provide the plant with the ability to produce an estimated 81 percent of the University’s yearly electricity consumption.
The Co-Gen system runs off of gas, producing 2.4 megawatts of electricity and using the excess heat from combustion to make steam and hot water. By harnessing this excess heat, the system is projected to operate at around 80 percent efficiency, in contrast to the 30 percent efficiency found in many conventional power plants.
This increased efficiency is projected to save the University around $5,000 a day on electricity—or around $750,000 a year after maintenance costs—according to Alan Rubacha, Consultant for Construction Services at Physical Plant.
Even with these built-in savings, it will take several years to cover the project’s $3.5 million price tag. Those involved in the project’s planning, however, say the Co-Gen system’s long-term financial and environmental benefits will speak for themselves.
“It’s a win-win situation, because we are saving money and supporting sustainable energy,” said Barry Chernoff, Director of the Environmental Studies Certificate Program.
Chernoff, a member of the Sustainability Advisory Committee, added that the plan to install the Co-Gen system had the full support of the Committee.
The costs of the Co-Gen system—which took nearly nine months to install—include around $4.6 million for the purchase of the system, design and testing fees, and costs of installation. The University received a $1.1 million rebate from the state of Connecticut, under a state-sponsored program to support sustainable energy, lowering the net cost to $3.5 million. The University’s annual electricity spending is approximately $8.5 million a year.
The Co-Gen system utilizes most of the heat from the combustion of fuel, making for a more efficient process than a regular power plant. The exhaust from the generator passes through pipes to a Selected Catalytic Unit, or a “scrubber,” that breaks down the harmful nitrogen oxides and hydrocarbons into relatively benign gases, such as nitrogen, oxygen and carbon dioxide. While carbon dioxide does cause a greenhouse effect, the nitrogen oxides and hydrocarbons that would otherwise be released are significantly more harmful to the environment. The scrubber also removes sulfur dioxide, a chief cause of acid rain.
The cleaned exhaust then goes through a large pipe that acts in the same way as a boiler—turning water into steam that can then be used for heating purposes—before being released into the air through a smokestack, constructed this past fall.
The Co-Gen reactor runs similarly to a car engine with a motor, and, like a car engine, requires water to keep it from overheating. This water will not be put to waste either—it will be used to heat High Rise and Low Rise.
The University’s decision to independently produce its own electricity came about through a combination of economic and environmental concerns. Connecticut had previously outlawed private energy production, until a 1998 restructuring of state laws. Even then, relatively cheap fixed electricity rates kept electric costs low, making it not feasible for the University to attempt private energy production. When regulatory changes caused electricity prices to significantly increase in 2004, the University created plans to begin producing electricity on campus. They turned to Peter Staye, Associate Director of Utilities Management at Physical Plant, who, having worked on two Co-Gen projects before, submitted a proposal to install one on campus. The project took off in 2006.
Staye praises the Co-Gen system in comparison to other, more antiquated models.
“This [Co-Gen plant] is so much better than a coal plant,” he said. “This is so much better than an oil plant. This is more efficient.”
Just because electricity produced on campus is cheaper than other forms of electricity, however, doesn’t mean that students and administration should expect to pay nothing.
“It’s not cheap, still,” he said. “And it is most definitely not free.”
The Co-Gen system will produce around 3,500 pounds of steam and around 6 million British thermal units (BTUs) an hour. It takes 10,000 BTUs to air condition 800 square feet, so 6 million BTUs could cool 480,000 square feet.
The power plant currently has three boilers that produce steam—two large ones can produce up to 50,000 pounds of steam an hour, and a “low load” boiler that can produce 25,000 pounds per hour. The University’s heat consumption varies greatly throughout the year—with amounts as high as 50,000 pounds of steam per hour in the winter, and lows closer to 5,000 pounds in the summer.
Unobtrusively situated underground, the power plant is the lowest point on campus. As such, the steam, which is lighter than air, gravitates upwards through pipes to get to campus buildings. When it has exhausted its energy and condensed into water, it flows back into the power plant through different pipes, creating a closed loop system.
The boilers can burn natural gas and, depending on the boiler, they can also burn either number six oil—which resembles crude oil—or number two oil, which is closer to diesel fuel. The fuel used in a boiler varies depending on different factors.
“We select our fuel choice based on economics with a very strong eye to emissions,” Staye said. “We are under an air permit here—we report our emission annually, and our fuel selection will affect our emissions.”
The University brought in outside consultants to design the setup for the system, which includes an engine, a generator, emissions control systems, gas compression, and a heat recovery boiler. With the exception of a couple of components available in the United States, all of the project’s physical elements were purchased from Austria. Given the relatively advanced state of European power systems compared to American ones, this comes as little surprise. Countries such as Denmark, the Netherlands and Finland produce up to 55 percent of their power through Co-Gen plants. In the U.S., the number is closer to 8 percent.
Chris Goy ’09, Chair of the Student Budget Committee (SBC), heralded the construction of the Co-Gen system as a push towards the future.
“This is the type of decision I really respect, making long-term decisions that may not be palatable in the short run,” he said. “It’s a clear indication of a concerted effort to break with the past in many ways—an agenda that moves Wesleyan forward.”
Margaux Weisman ’09 expressed similar sentiments regarding the University’s support for the project.
“This is a concrete and cognizant example of the way in which Wesleyan cares,” she said. “This is something students can understand and learn from.”
In order to be compatible with the New England power grid, a sophisticated system has been set up in the power plant to assure that no damage ensues.
“The Vine Street substation is our gateway to the New England system,” Rubacha said. “You need to integrate your generator into the larger electrical system.”
According to Staye, however, the University’s power system will now be operating at a greater level of efficiency than many other plants within the grid.
“The New England power grid is not a healthy grid,” he said. “If the Wesleyan power plant can run at higher efficiency, it can replace the need for another, more environmentally damaging power plant to run.”
The generator will produce 4150 volts—enough to kill a person twenty times over—and if not integrated properly, the generator could easily explode.
It is partially for this reason that Central Power Plant Foreman David Pompei and other workers at the Central Power Plant will go through a week of training in how to use the new equipment and what to do in case of emergency.
“[The Co-Gen System] is different in a lot of regards from what we already have here,” Pompei said. “Every situation is going to be different.”
The generator will run eight hours a day for the next week to make sure that everything is running properly. Following a test to check compliance with emissions regulations, it will run continuously.
“It’s a big investment, a lot of time, a lot of effort,” Rubacha said. “A lot of power.”