Harvesting Forestry and Logging Waste Profitably
If one man’s trash is another’s treasure, then harvesting that treasure and transforming it into a saleable resource just got easier. By modifying their field-proven line of mulchers and chippers, Fecon Inc. engineers, working with Joe Roise, an industry leader in forestry from North Carolina State University, have developed a line of biomass harvesters that transform the slash and debris from forestry and logging operations into biomass fuel. These technologies provide another revenue stream for foresters, loggers and contractors who work in the woods and address ecological (and economic) concerns such as sustainable energy, forest fire fuels reduction and wildlife habitat restoration.
Abundance of Opportunity
Woody biomass in North American forests is a concern because the fast-burning underbrush provides a “ladder” for fires to reach tall tree tops, which is the fastest way to spread forest fires. The underbrush also endangers species such as the red-cockaded woodpecker because the brush allows predators easy access to their nests.
At the same time, as a nation we are striving to enhance our production of sustainable energy. Clearly something must be done. Fecon engineers have developed new products to harvest the woody debris that is at the root of the problem, and use it for biomass power generation facilities. The electricity generated would be cleaner—emitting less CO2 into the atmosphere—while reducing our dependence on foreign oil. And the woody debris is carbon neutral because plants are part of the atmospheric carbon cycle.
Currently, 27 states have renewable electricity standards in place—a measure of the importance of renewable and sustainable energy production. Each state has mandated that a certain percentage of their energy must be generated through sustainable means by a target date. For example, Ohio must generate 12.5 percent of its electricity demand through renewable resources by 2025. North Carolina, where Roise lives and works, is more aggressive, targeting 12.5 percent of its retail electricity demand through renewable energy by 2021.
While there are numerous cogeneration facilities around the country that can accept biomass materials, there are nowhere near enough to provide 12.5 percent of the retail electricity demand. That is due to several reasons—not the least of which is supply. Currently, the only way to economically harvest woody material for cogeneration facilities is to harvest mature trees and utilize the tops and branches. Residual biomass is a byproduct of traditional forest product harvesting and much of the cost is supported by saw timber and pulp. Thus the biomass supply will fluctuate with the demand for lumber and paper, which is not ideal for supplying energy to a cogen facility.
Conventional forest harvesting requires workers with specialized equipment, including feller bunchers and whole tree chippers. Add the costs to transport the harvested biomass to a cogen facility (which would be offset by the price the facility pays for clean cogen materials) and it is understandable why the geographic range for these activities is limited.
It is only economically feasible to harvest biomass near cogen facilities. Because conventional methods harvest mature trees and leave the underbrush, the problems with ecosystem degradation and the potential for catastrophic forest fires still exist.
“It is a chicken and egg situation,” Roise says. “Without a supply of material it does not make sense to build the plants – and without a market for the materials, why would you own the equipment?”
But Roise and the Fecon team have a vision to change that by working together to build and test several variations of biomass harvesting 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 $1,000-plus 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.”
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.