Through torrefaction, vegetative waste–or biomass–is heated without oxygen to temperatures between 250 and 300 degrees Celsius. The result is a cleaner-burning, energy-dense renewable energy source that RFT calls BioCoal.
“We recognize that it’s going to be important to be involved in biomass work. Often, the slash from logging or the residue from fuel reduction cuts just gets burned. It’s a waste of energy and it adds to pollution,” says Schatz Lab co-director Peter Lehman. “But when biomass is wet and green, it’s often not worth the time and energy to take it out of the forest.”
The torrefier that researchers will be working with, the RFT BioCoal Processor, is a prototype, but the hope is Schatz Lab’s involvement will help RFT design a commercially viable system that is also self-sustaining.
The benefit of a self-sustaining torrefier would be its portability. “It can be put on a trailer and taken out to the woods to be used in a remote location where utility services aren’t available,” Lehman says. However, to do that, Schatz Lab researchers must find a way to use the machine itself to produce all the heat and electricity needed to run it and also produce BioCoal. This heat and electricity can come from torrgas–a gaseous renewable energy byproduct of torrefaction.
“They’re aiming to get to a point where they can get up to one ton of torrefied wood per hour from a stand-alone system,” Lehman says.
Schatz Lab researchers and student research assistants will torrefy woods of different types and moisture contents for different amounts of time. Their results will help inform design aspects for a final commercial product.
An improved design will benefit local communities as well as RFT. In discussions with local energy industry leaders, Schatz Lab researchers have found that there is a potential market for torrefied biomass. “People are willing to pay a premium for dry, clean burning fuel,” says Lehman. “Torrefied biomass is an obvious way to achieve this sustainably.”
Although not directly related to the work with RFT, another Schatz Lab venture could help Humboldt County make use of torrefied biomass. The Renewable Energy Secure Communities (RESCO) project, a partnership between the Schatz Lab, the California Energy Commission, and Redwood Coast Energy Authority, has created a strategy to meet 75 percent of Humboldt County’s energy needs with renewable energy. Forest biomass, already used to generate 40 percent of the county’s electricity, will play an even more important role in the future envisioned by RESCO.
“Torrefaction is an important opportunity to achieve the as-yet-unrealized biomass potential in Humboldt County that RESCO has identified,” says Schatz Lab senior research engineer Richard Engel.