Wood chips could be UNCs replacement for coal

As the University reviews the results from its first large-scale biomass test in its quest to become coal free, new materials to test have appeared on the horizon.

An Energy Services draft report, due to be finalized in the spring, says dried wood pellets burned well when co-fired with coal during March tests.

“There were no showstoppers identified in the testing,” said Ray DuBose, director of the Energy Services department.

One problem encountered in the tests was that the boilers at the Cogeneration Plant could only be loaded to 75 percent capacity because of the nature of the fuel.

Woody biomass fuels are lighter than coal and can blow away from the conveyor belt that loads them into the boilers, DuBose said.

If the University uses a wood biomass product to fulfill obligation of using 20 percent alternative fuel in the Cogeneration Plant by 2015, it will have to invest in new equipment to solve those loading problems.

“The more testing we do, the more certainty we have about what we can do,” he said.

With dried wood pellet tests behind it, UNC is looking to additional forms of wood biomass for its future.

Phil Barner, cogeneration systems manager for Energy Services, said the department has been testing samples of dried wood chips in preparation for possible large-scale tests in the spring.

Dried wood chips differ from dried wood pellets in that they haven’t been compressed into pellet form. Barner said wood chips cost about 20 percent less than pellets, but produce roughly 6 percent less energy.

Both fuels differ from torrefied wood pellets because they haven’t undergone the torrefaction process that removes moisture from wood.

In addition to dried wood chips, the University is testing samples from New Biomass Energy, a torrefied wood supplier in Mississippi. The news comes after two attempts to secure the fuel failed during the summer.

The market for woody biomass is a small one, and Energy Services has had trouble finding reliable suppliers.

DuBose said he did not know why New Biomass Energy missed both summer deadlines. The company did not immediately respond to an email request for comment Friday.

Still, Barner said he has confidence that a bid for both fuels could be issued by February.

“They’ve both got a high probability of happening,” he said.

Stewart Boss, co-chairman of the group that lobbied UNC to reduce its coal use, the Sierra Student Coalition, was encouraged by the announcement of new biomass tests.

“We’re excited to see them moving in the right direction,” Boss said.

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