¦TECHNOLOGY Simple Concept, Difficult Delivery The Bio-Harvester started out as an adaptation to the Fecon line of mulchers, which are used to clear rights-of-way for utilities, remove underbrush to mitigate forest fuels loading and general land clearing for development and habitat restoration projects. Until now, the shredded material was left on the ground. With the Bio-Harvester, however, the shredded materials are collected and blown into an attached collection wagon called a hopper. When full, the hopper is emptied into a truck for transport to a cogeneration facility. Materials are handled once by a single operator, making it simpler and more economical to harvest. While the concept is simple, the devil is in the details. For starters, the rotor which contains the teeth that shred the woody materials is flipped so that it rotates backwards, discharging materials upward rather than downward. Previously the design used the ground as an anvil to help tear woody materials apart—now the upward rotation simplifies collection but at a cost (smaller diameter materials are targeted). A second technology—fitting a drum chipper onto a tracked carriage—is also being developed for harvesting biomass. So far, initial testing of both methodologies is promising. Operators are able to tweak the machines’ performance, bringing them closer to providing a machine that will increase the range of harvesting biomass further from cogeneration facilities.
Processing Parameters, Operator Preferences When the team designed and built the first prototype Bio-Harvester they were striving to produce 10 tons per hour of shredded green waste that could be harvested by a single operator. “The machine is designed for materials less than 8 inches in diameter at breast height,” says Mark Ferguson, Fecon product manager. “It is designed to gather materials that are not practically harvested by any other method.”
Fecon has also developed the RTC-22, a disc chipper mounted to a tracked machine called a forwarder, which chips waste material from logging operations and other forestry applications. This tracked carrier is equipped with a grapple to feed the woody debris into the chipper. The RTC can handle materials up to 22 inches in diameter, and has a processing speed of 35 to 40 tons per hour. “Each technology addresses a different need,” says Brian Sellers, RTC product manager. “The RTC is ideal for chipping of debris left from cut-to-length logging operations. If material is stacked and ready at a landing site, we can process 35 to 40 tons per hour of good quality fuel chips.” These production rates take into account the assumption that cogen facilities will pay $18 to $28 per ton for materials (the rates at time of initial testing). Naturally, if the price increases over these rates, then the operations have more leniencies in terms of their production rate, operating costs or profit margins. Additionally, some states (including Texas) have matching funds to supplement the price of biomass and help develop markets, or ensure an adequate supply of material. Also the federal Biomass Crop Assistance Program program will provide matching funds to biomass producers who deliver to a processing facility. These numbers do not take into account the fact that landowners currently pay $500 to $1,000plus per acre to mulch brush and hazardous fuels.
Fuels Reduction Potential In addition to the potential for developing sustainable energy and reducing dependence on coal or oil, the Bio-Harvester also shows potential for fuels reduction in forests, which are clogged with underbrush due to what could be considered the law of unintended consequences. “In the past 60 years or so we have been very successful in suppressing fires,” Roise says. “Unfortunately that has allowed the growth of brush to continue unchecked— creating an unprecedented buildup of flammable materials in the forest.”
58 BIOMASS POWER & THERMAL | NOVEMBER 2010
While eliminating this nuisance is important, using the materials for a beneficial purpose is why Roise and the Bio-Harvester team are excited about their success. Another unintended consequence of the growth of underbrush in our forests is that it alters ecosystems. Take the endangered red-cockaded woodpecker, for example. When forest fires would naturally maintain the growth of brush, the red-cockaded woodpecker was relatively safe in its nests. As brush grows higher, though, its habitat becomes more undesirable as natural predators such as snakes can slither through the brush, giving easy access to the woodpeckers’ nests. Disappearing habitat has catapulted the red-cockaded woodpecker onto the list of endangered species. A Bio-Harvester test in North Carolina successfully re-established habitat for the red-cockaded woodpecker by removing the hazardous fuel load and clearing the way for lower intensity prescribed fire treatments. As various states and the country as a whole seek to increase the percentage of electricity generated from renewable resources, biomass power generation is poised to provide more electricity to the grid. Until now, a stumbling block has been the supply of clean green waste to burn. One reason for that shortage is because operators using multiperson crews are limited to a short distance from the cogen facilities. This technology allows a single operator to profitably process materials for cogeneration or wood waste power plants. Seeing this equipment in action is an example of sustainability and keeping Americans employed making the equipment that allows contractors to work in the woods. More importantly, it is an example of turning trash into treasure—clean, sustainably generated electricity—that we can all enjoy. Authors: John Heekin President, Fecon Inc. (800) 528-3113 www.fecon.com