MU Fires Up Biomass Boiler
The long-awaited boiler will use sustainably sourced biomass.
After roughly four years of analysis and design, two years of construction and road closures, more than 150 contractor employees and $75 million of equipment and labor, Gregg Coffin will be happy to see MU’s new biomass boiler operating at full capacity.
“In the course of a project, you’re always excited when you get close to the end,” Coffin, the plant superintendent, says. “It’s a relief to start seeing [contractors] leave and things get finished so we can work our way back to normal.”
He’s almost there.
The lining of the new 85-feet-tall boiler finished curing in late November, which allowed Coffin to start burning biomass gradually. The boiler uses natural gas during its startup phase, but Coffin hopes to be running solely on biomass starting this week.
It’s an incremental process to bring the boiler to full capacity. Workers will add fuel, adjust the oxygen levels to calibrate the burn, then add a little more fuel, recalibrate, and so on. They’ll be making usable energy by the end of the year, but the ramping-up process will likely continue into February. At that point, they’ll test to make sure they’re meeting the capacity, emissions and efficiency standards promised by the manufacturer.
The work is the final phase of a project that started in 2007 when the university decided to replace one of the power plant’s old and increasingly unreliable coal-fired boilers. A design team researched options and found that a biomass boiler, while more expensive to purchase, offered the lowest ownership cost for installation, maintenance, operation and fuel over the equipment’s 30-year lifespan.
The boiler’s $75 million price tag is being financed primarily through bonds that are being repaid from power plant revenue (the plant charges campus units for steam and electricity usage).
Because the biomass boiler will produce more steam and electricity than the coal boiler it is replacing, the new boiler will be able to take some work away from the remaining four coal boilers. Coffin expects the plant’s coal usage will decline by more than 25 percent. And by using sustainably sourced biomass, the new boiler will reduce the power plant’s emissions and shrink the university’s carbon footprint. Coffin contends the project is the biggest sustainable energy project on any major American university campus.
Overall, the power plant can produce 66 megawatts of electricity and 1.1 million pounds of steam an hour — enough to service more than 13 million square feet of campus buildings.
The biomass boiler will use 100,000 tons of biomass a year, which will be delivered by a dozen or more semitrailers a day and stored in three large covered silos.
At first, the biomass will be wood waste from mills, managed forestry and clearing for development. MU signed a six-year agreement with Foster Brothers Wood Products of Auxvasse, Mo., to supply biomass to the plant. But the boiler is flexible. It uses a “fluidized bed” — a layer of heated sand that bubbles like boiling liquid — that is able to ignite a host of fuels with a range of moisture contents. So if prices change and other fuel sources — switchgrass, corn stover or other agricultural residues — become cheaper, the boiler can follow the market.
Cerry Klein, LaPierre Professor of Engineering, says the new boiler will be a boon for campus research.
“I think it’s a tremendous asset,” Klein says. “Our plant scientists … will be able to do test burns in this boiler and see exactly what particulates come out based on different plants and how they genetically modify them, and also what burns better and what gives us a better return on BTU for our money. That is an advantage to us because in most places you can’t do that.”
Coffin says he hopes researchers and their students can develop a deep bench of backup fuel sources that he can call on when the price game changes. “It does make a good opportunity to partner with our academic community … to help them and them help us develop new sources of biofuel that can be used in the plant,” Coffin says.
Shibu Jose, H.E. Garrett Professor of Agroforestry, studies biomass production and how it can be done sustainably and economically.
“There are all sorts of questions surrounding the logistics of producing the biomass and getting that biomass to the end user,” he says, including how the biomass is produced, harvested, stored, transported and processed. “These are all topics we can research to make sure it’s the most cost-effective way of procuring the biomass for the boiler — and perhaps an economically viable opportunity for the landowners involved.”
Coffin hopes that operating a biomass boiler will help stoke the biomass fuel market and create local jobs. The power plant’s coal and natural gas all come from out of state — Illinois, Texas and Oklahoma — but Foster Brothers is a Missouri company creating Missouri jobs. “That’s good for Missouri,” he says.