Figure 1—The 25-kilowatt mobile BioMax system at MTDC closed for storage or travel (top) and open for operation (bottom).
If you can't see the electricity for the trees, you're not considering the potential of biomass gasification.
When wood chips are heated in special vessels, known as gasifiers, the chips produce a variety of gases that can power an internal combustion engine and generate electricity (or power an automobile in Europe, Asia, and Australia during World War II).
Since 2008, the University of Montana's Bioenergy Program has operated a mobile 25-kilowatt BioMax system (figure 1) in cooperation with the Missoula Technology and Development Center (MTDC).
The $500,000 system was purchased through a U.S. Department of Agriculture and U.S. Department of Energy collaborative Biomass Research and Development Initiative grant.
When the BioMax system is not being used for a demonstration, it's stored at MTDC. The BioMax system is unused much of the time its at MTDC because the amount of electricity that it generates does not cover the cost of someone to operate the system.
When the system is operating, the electricity it generates is fed into MTDC's office building.
The BioMax system also generates 200,000 British Thermal Units of heat an hour (about enough heat for two 2,300 square-foot homes in Montana's climate).
Figure 2—Wood chips (left) are a desirable fuel for gasification because their shape and size are uniform. Shreddings (right) can cause uneven heating and can jam the equipment.
Waste heat generated by the system (more than half of the total energy generated) now dries the wood chips used as fuel. Fully using the waste heat is key to economical operation of the system.
Each hour, the BioMax system uses 50 pounds of wood chips (figures 2 and 3). Fifty pounds of wood chips is the energy equivalent of 3.3 gallons of gasoline. The system has also been operated using wood pellets, coconut shells, chicken litter, coffee husks, corn, and soybeans.
Figure 3—This grate screens out chips that are too small or too large as fuel is fed into the BioMax system.
Additional information on the BioMax system at MTDC and similar systems at the Winn Ranger District in Winnfield, LA, and at Auburn University is in the tech tip, "The Promises and Pitfalls of Using Wood To Produce Electricity" (http://www.fs.fed.us/t-d/pubs/htmlpubs/htm10732315, username: t-d, password: t-d).
To learn more about the University of Montana's BioEnergy project, go to http://www.um-bioenergy.org or contact Brian Kerns (firstname.lastname@example.org).
More information on the grant for the BioEnergy project can be found at http://www.nrcs.usda.gov/technical/grants.html.
The BioMax systems are produced by the Community Power Corp. in Littleton, CO (http://www.gocpc.com/).