Sometimes the right thing to do just hits a person over the head … literally.
That might be how Mike Thatcher, vice president, generation, explains Corn Belt Power Cooperative’s decision to replace the exhaust stack at the Webster City Combustion Turbine, Webster City.
Last year, when Thatcher was onsite and the unit was operating, a relatively large piece of rusted metal broke loose from the stack. It flew out and hit Thatcher on top of his hard hat, serving not only as a reinforcement of the importance of personal safety devices, but also as an indicator the 1970s original stack was due to be replaced.
“We’ve been monitoring it through the years, and the stack was no longer structurally sound,” Thatcher explains. “The baffles were misaligned and the brackets that held them were deteriorated. It was beyond its useful life.”
The Webster City Combustion Turbine is a reserve unit that rarely runs. It is called on to operate for testing about four times a year and runs only once or twice a year to cover generating needs. Thatcher explains that keeping the unit operational contributes to the needed amount of generation reserves.
“It provides dispatchable power supply and necessary generation reserves. Other plants that operate all of the time must come down for maintenance or they may have an unexpected outage that needs to be covered,” he says.
Although the unit is owned by the City of Webster City, Corn Belt Power operates and maintains the plant through a long-term contract. Its capacity is 25 megawatts in the winter and 20 megawatts in the summer.
B&W Universal, Wisconsin, was awarded the bid to manufacture and install a new 48-foot-tall stack. The turnkey project was completed in October, at a cost of approximately $400,000. Webster City personnel assisted with removal of a fence for the project.
With the new stack installed, Thatcher says the unit will be ready to operate when called upon. “New controls were added to the unit a few years ago, so now with the new stack, we should get another 10 years out of the plant.”