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March 14, 2012 Volume 33, No. 24

Biomass-fueled boiler to be operational this year, Campus Facilities officials say


Biomass is a cleaner alternative to coal

Construction is underway on the 100 percent biomass-fueled boiler at MU’s power plant. When operational later this year, the boiler could shrink the plant’s coal usage by a wide margin.

The power plant might be considered the James Brown of the university. Churning up to 66 megawatts of electricity and 1.1 million pounds of steam each hour, it’s undoubtedly the hardest working facility on campus.

As coal-fired plants go, MU’s is more efficient than most. Because it produces thermal heat and electrical power at the same time, the plant burns a third less coal than power-only plants, resulting in about 100,000 fewer tons of greenhouse gas emissions.

The plant’s coal usage could decrease by 25 percent by the middle of this year, when the new boiler goes online. At first, it will burn mostly waste from wood milling operations. Campus Facilities’ Energy Management officials expect to eventually use up to 140,000 tons annually of  sustainable biomass from various sources in Missouri: waste wood; corn cobs and stalks; prairie grasses, such as miscanthus and switchgrass; and fast-growing trees, such as willow and cottonwood.

“For the long term, we’re looking at what some people call closed-loop biomass,” said Gregg Coffin, superintendent of the power plant. “That’s biomass specifically grown to produce energy.”

CAFNR connection

The new boiler will feature what’s called a bubbling fluidized bed. Coffin described it as a large container of sand that heats up to 1,600 degrees Fahrenheit. When hot sand becomes like fluid, the liquid acts as a thermal flywheel that consumes fuels with high moisture content. The heat is turned into steam to generate electricity and thermal energy for the campus.

Coffin and his biomass team, which includes researchers from the College of Agriculture, Food and Natural Resources (CAFNR) and MU Extension, have been exploring alternatives to coal since 1995, when they started burning chipped tires. Corn cobs were added to the mixture in 2006, and a year later the team tested woody biomass from mill waste, development clearing and discarded pallets.

In June 2010, the plant received an Energy Star Combined Heat and Power Award from the Environmental Protection Agency for its efficiency, which lowers greenhouse gas emissions.

Three of the five new silos being constructed will be used to store biomass material.

In 2010, MU was developing plans to replace one of its five coal-fired boilers. Coffin said the university had initially considered a boiler fueled by natural gas or a coal boiler that could take a higher percentage of biomass. Despite the plant’s early success with coal alternatives, there was still a lot to be learned about biomass, including figuring out what Coffin calls “the chicken and egg thing.

“No one is going to develop a biomass source unless someone builds a plant to consume it,” he explained. “But once the plant is operational and consuming the biomass, there will be more and more people interested in developing those sources.”

Crops to burn

One key to the new boiler’s success is located across campus, at the forestry department in the School of Natural Resources and the MU Center for Agroforestry in the Anheuser-Busch Natural Resources Building. Along with extension specialist Hank Stelzer, forestry researchers are identifying and developing viable energy crops, while scouting growing locations such as river bottoms and other land unsuitable for conventional row crops.

They also are exploring ways to tap the state’s 14 million acres of forest. Stelzer has developed an interactive spatial analysis tool that screens locations that might be good sources of sustainable woody biomass. He and other forestry experts are establishing research plots to test various species of trees as energy crops, while developing guidelines that will protect the health of the forests.

“We have set a really high bar in that we will only be taking wood from the forest once there is a management plan in place,” Stelzer said. 

“A professional forester has to be involved not only in the development of the [biomass] plan, but also in the harvesting,” he said. “Following that through and showing it can be done in a sustainable way, that’s going to set a standard for other biomass projects in the state.”

Back at the power plant, Coffin and his operations staff will need to answer some questions of their own. Can the boiler handle 

100 percent switchgrass, or will it be necessary to mix it with an equal amount of woody biomass? What’s the optimum combustion temperature?

Corn cobs and grasses have a high alkaline content compared to wood, which can cause problems with the boiler’s mechanics and impair the efficiency of heat transfer. What are the costs in time and money of maintaining a 100 percent biomass boiler?

“There’s very limited knowledge,” Coffin said. “We’ll have to learn what temperatures, the blend ratios, how often we have to change out the bed material and clean the tube surface.

“That’s something we’ll likely continue to partner with the academic community along with the boiler manufacturer to find out,” he said. “There’s the expertise to work together, to find out what types of these fuels can be consumed and what form do they have to be consumed in. There are some challenges ahead, but we’ll work through them.”

Reducing carbon emisions

Gary Ward, associate vice chancellor for Campus Facilities, said the decision to go with a 100 percent biomass boiler was partly the result of “reading the tea leaves.”

In January 2009, Chancellor Brady J. Deaton joined 650 other higher education leaders in signing the American College and University Presidents’ Climate Commitment. MU’s pledge is to reduce carbon emissions by 20 percent from 2008 levels by 2015, a goal that largely depends on reducing the amount of coal burned at the power plant.

Ward noticed that sustainability was becoming more important to students, faculty and staff. The university announced an official policy in March 2010 that strongly encourages departments to adopt environmentally sustainable practices. And in the past few years, student organizations have launched recycling and composting projects, as well as a program that awards small grants for student projects that demonstrate environmental stewardship.

“The biomass boiler fell right in line with the campus wanting to become a greener campus,” Ward said. “We were starting to see a lot of change within stakeholders of the university and society in general of trying to get away from coal and find some other fuel sources.”

Although it will be some time before other energy sources, such as solar and wind, are viable on a large scale, Coffin and Ward say Campus Facilities is willing to explore those options through demonstration projects. The department has accepted bids to install solar panels on the sloped side of a building at the power plant, and a small windmill is being considered for the grounds of the old Beef Barn at the corner of Stadium Boulevard and Champions Drive.

“As an energy provider, we need to learn how these technologies work because they will get more efficient and may at some point make more economic sense,” Coffin said. “So we need to educate our staff, as well as our students and faculty.”

— Brian J. Wallstin

This article originally appeared in the Winter 2012 edition of MIZZOU, the magazine of the Mizzou Alumni Association.