Dead standing trees are the ideal fuel for wildfires, but what if they could be used as fuel for something else? Researchers at Brigham Young University have developed a new way to convert decaying, dead trees into biomass fuel that can be used at coal power plants.

According to Andrew Fry, a BYU chemical engineering professor, there are some forests in the western United States where over 70% of trees are dead and standing. One common cause of death for these trees is the bark beetle, a type of small beetle that burrows under the bark of a tree to reproduce, eventually causing the tree to decay and die.

“Using biomass as a fuel isn’t a new concept, it’s something that’s been worked on for many many years,” Fry said. “But it became apparent several years ago that it was a technology that could be leveraged in the western United States and really specifically in the Salt Lake area for both offsetting CO2 emissions from coal-fired utility boilers but also to clean up dead trees in our national forests.”

Fry and his fellow researchers began to work on a way to kill two birds with one stone by reducing the wildfire potential while also offsetting some carbon emissions.

“To create this fuel, Fry used two different approaches. One was to shred the trees down to very small particles and then heat them for a period of time, a process called torrefaction. The other approach, called steam explosion, was used to pressurize the shredded wood material with steam, then release the pressure rapidly,” reads a press release distributed by BYU. “These methods were crucial to the development of the new fuel because they provided a way to break down the lignin structure of the trees — the stranded material that makes wood so strong. Once that structure is broken, the processed biomass can be pressed into pellets and treated like coal.”

In 2019, Fry and his fellow researchers demonstrated the fuel they had created at the Hunter Power Plant in Emery County where, according to the press release, they successfully burned 900 tons of biomass mixed with coal for 24 hours.

“This demonstration was a major milestone, largely because it revealed that there were no significant changes in ash deposition from coal vs. co-fired coal and biomass material and showed that biomass fuel can be safely and effectively used in power plants,” read the press release.

Fry and his fellow researchers will continue working with power plants to make biomass fuel a more plausible option for coal-fired power plants. He hopes that this is part of a bright future for renewable fuels.

“I hope that people can understand that the amount of energy that we can produce and consume is far beyond any one renewable resource,” Fry said. “We need to have a little more open mind about what we are willing to deal with in the future.”

This study was recently published in the journal of Energy & Fuel. Xiaolong Li and Jost O.L. Wendt of the Department of Chemical Engineering and Institute for Clean and Secure Energy at the University of Utah were research collaborators on this project and BYU graduate students Seyedhassan Fakourian and Boden Moyer were co-authors.

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