A Salt Lake manufacturing company creatively manipulates woody biomass into wood pellets, which can be used as fuel for heating homes and other buildings, as fuel for producing electricity, and also as animal bedding. ArborPellet LLC is part of the growing international wood pellet industry which is conscientious about decreasing pollution and greenhouse gas emission and also about promoting a renewable energy source.
While working for 24 years in urban forestry, the founder of ArborPellet, Brian Getzelman, saw the decisions society had been making regarding the use of its residual tree products or urban wood waste. Wood waste was either buried wastefully in landfills or ground into compost or mulch. In 2007 and 2008 he built a wood pellet manufacturing plant to help provide society with a better option. The wood pellet industry began in the 1930’s, expanded in the 1970’s following the energy crisis, and spurted in the last decade as fossil fuel costs have risen. In fact, wood pellet production capacity in North America increased from 1.1 million metric tonnes in 2003 to 4.2 million in 2008, according to research done on North America’s wood pellet sector by the U.S. Forest Service’s Forest Products Laboratory.
Getzelman largely makes his wood pellets out of fiber from urban wood waste, generally in the form of wood pallets used for shipping. He does not use urban wood in the form of green tree waste because its high moisture content makes it unusable without undergoing a drying process which would require the purchase of more expensive equipment. He also uses some fiber from secondary manufacturing facilities like cabinet and furniture makers, using their high quality scrap cutoffs.
Small mountains of wood pallets and scrap wood can be seen at his Salt Lake City plant. Getzelman said that wood pallets are made from a large variety of wood types and that “the number one use of wood in the country is for wood pallets. Wood pallets are often designed and built to ship a specific product. Once that product gets shipped it’s not cost effective to save that pallet and ship it back and reuse it just because shipping costs are so expensive.” While grocery pallets are an exception to the rule because they are generally rebuilt and reused, the broken boards being replaced with new boards, Getzelman said that he still gets “a lot of those broken boards from some pallet rebuilders. And we grind that up and make wood pellets.”
The Forest Products Laboratory identified at least 111 operating or nascent wood pellet producers in North America in 2009. Getzelman knows of five wood pellet manufacturers in Utah and one in Evanston, Wyoming. ArborPellet is rather unique in its exclusive use of urban wood waste and cutoff scraps from secondary manufacturing facilities instead of sawmill residues or green material.
The Forest Products Laboratory found that only about 1% of the fiber used to produce wood pellets in North America in 2008 came from urban or salvage wood and only about 14% came from secondary manufacturing facilities. Moreover, 69% of North America’s wood pellet fiber was sawmill residues and 16% was green material from pulpwood or logging residues. Most wood pellet plants depend on fiber from sawmill residues and, consequently, are located near mills. Getzelman sees some potential for utilizing some of these wetter materials (e.g., sawdust or urban tree waste) in summer pellet production by mixing them with his drier scrap wood which is too dry in the summer to be properly used in making wood pellets without the addition of supplementary moisture to the fiber.
Around 1 million U.S. homes are being heated by wood pellets, according to the Pellet Fuels Institute (PFI), a North American trade association promoting the wood pellet industry. Wood pellets are being used in freestanding stoves and fireplace inserts or in furnaces and boilers. They also have the potential to be used in larger public and commercial buildings. “What I’d like to see is the BLM and the Forest Service take all their offices and facilities that use propane and switch them over to wood pellets. That would really help our industry,” said Getzelman.
Although there is a significant market for wood pellets in the U.S., the biggest market for wood pellets is in Europe. Nations within the European Union are ambitiously attempting to meet 20% of their energy needs by means of renewable sources by the year 2020. According to Getzelman, “Europe is like the black hole for wood pellets. They just can’t get enough of them.” He has found that shipping beyond the neighboring states is not economical for him. Regardless, people in Europe regularly contact him, requesting that he ship some of his product to them in Europe.
Because wood pellets are derived from raw wood, which is carbon neutral and renewable, using wood pellets as a fuel is an attractive alternative to using fossil fuels such as coal, natural gas, propane, and heating oil. Moreover, heating with wood pellets is sometimes less expensive than heating with fossil fuels, relative to the heat output. For example, in smaller communities where natural gas is unavailable and propane is commonly used, burning wood pellets is a way to save money.
Although wood pellets probably should only be classified as a partially renewable energy source because their production can require large amounts of electricity, heating with wood pellets has a number of advantages over heating with raw firewood. First, burning wood pellets instead of firewood reduces the emission of harmful particulates because pellets burn hotter and more completely due to lower moisture content – an appealing option in regions prone to inversions like Cache Valley and the Wasatch Front. Second, wood pellets are cleaner to burn than firewood, making wood pellet stoves easier to clean because PFI’s new quality standards encourage low inorganic ash content for pellets of a higher grade. Third, burning wood pellets is more effective or efficient than burning firewood because pelletization densifies the wood, making the energy content per unit volume higher – near the energy content of coal. Fourth, the higher bulk density of wood pellets makes hauling them more economical than firewood. Finally, their consistent, small size allows for more user convenience because the fuel feed in pellet burning stoves can be automated.
In addition to their utility as a heating fuel, wood pellets are also being used for animal bedding. Getzelman said “we do make wood pellet animal bedding. That’s turned out to be a pretty big percentage of our sales.” Instead of burning the pellets, animal owners use it for bedding and then can collect and compost the resulting mix of wood and manure.
Another potential use for wood pellets is electricity production. Utah State University installed a new Central Energy Plant in 2002. The Central Energy Plant uses natural gas to produce steam, which then heats buildings on campus, and also to produce some of campus’ electricity. Getzelman thinks that USU should have built the plant to run on wood pellets or wood chips instead of natural gas. He said, “You could basically do the same thing with wood. You could take wood chips or wood pellets, turn that into a wood gas, and then run that gas through the turbine and do the same thing; and then the byproduct would be biochar, which could be used as a soil amendment.” If the university had installed such an energy plant, it could have become even more of a leader in promoting the use of alternative, renewable fuels. In any case, Getzelman and the growing number of other advocates for the use of woody biomass as an energy source would have been appreciative.