Providing efficient heating, cooling is a changing game
The arctic air masses that swept through Illinois this winter have given Abbott Power Plant a workout. Abbott provides the steam that heats most campus buildings and that generates a portion of the campus’s electricity with steam-driven turbines through the process of cogeneration.
“The cogeneration process is more efficient, and as a result costs less and produces less pollution than a commercial power plant,” said Mike Larson, director of utility operations.
The power plant uses a variety of fuel sources – natural gas, fuel oil, and coal – to produce heat for workplaces, residences, classrooms and the myriad other environments that make up the university campus.
With the bitterly cold temperatures that the campus experienced during January and early February, “peak steam production with the subzero temperatures was around 660,000 pounds an hour,” Larson said. “When we get numbers in that range, we start to lose some of the redundancy” provided by having multiple boilers using a variety of fuel sources. “We could handle a little bit more load, but as we add more load we lessen the amount of backup systems that are able to support the campus in the event something should happen,” Larson said.
During the summer months, steam production may dip to about 300,000 pounds an hour. When the temperatures are soaring outdoors, steam powers some of the chillers that provide air conditioning. The campus has about 30,000 tons of chiller capacity provided by five plants – on Oak Street in Champaign, the North Campus Chiller Plant east of Beckman Institute, at the Main Library, in the Animal Sciences building, and at the Veterinary Medicine complex. The Oak Street plant was constructed as part of a $45 million expansion and upgrade project that centralized the system a few years ago.
“We’re in the process of getting the controls and data at the chiller plants into a common digital control system,” which is expected to take about two years, Larson said.
Since Abbott was built in 1941, the fuel source for the plant’s boilers has changed several times as the university sought to operate the plant as economically as possible. Abbott’s boilers were all fired by coal when the plant began operating in 1941, but in the early 1970s the campus discontinued burning coal and switched to natural gas, which was to be provided by Illinois Power Co. But when Illinois Power didn’t receive a sufficient allocation to meet the UI’s energy needs, Abbott had to burn fuel oil instead.
In 1978, Illinois Gov. Jim Thompson asked the UI to convert Abbott back to coal to boost the state’s coal industry by demonstrating that the high-sulfur coal mined in Illinois could be burned safely. The plant uses electrostatic precipitators to remove particulates and a wet scrubber to remove potentially hazardous sulfur dioxide, which can cause respiratory problems, from the plant’s flue gases before they are released into the atmosphere. “The wet scrubber technology that we have for flue gas scrubbing is one of, if not the, best available today, and it has been in place for about 20 years,” Larson said.
“The university has an air permit from the Environmental Protection Agency that regulates how we operate the plant,” Larson said. “On our coal boilers, we have continuous emission monitoring equipment online at all times. If we stray out of the permit-operating parameters, we have to react and report that to the EPA.”
All of the energy-production equipment in Abbott can be monitored and/or controlled online through different software systems.
When fuel oil prices rose as a result of the nation’s oil embargo that began in 1973, three boilers were converted in 1979 so they could run on natural gas or fuel oil, providing the flexibility to take advantage of the best market prices. “Coal has been the cheapest fuel source by far in recent history,” Larson said. “If that changes, we have the flexibility to go either way” with the other fuel sources. “With coal boilers, there are times when you have to take them offline for a week or two for maintenance, and we need some kind of backup in order to do that.”
