USA — It has been said that one mans trash is another mans treasure. That could well be the driving force behind a new product development effort at Fecon. Here design engineers are working to adapt their proven mulching technology to harvest (rather than merely mulch) the woody biomass that is cluttering much of the forested lands in North America. Early indications are that this new technology will be a winner not only from a sustainable energy production standpoint, but also from the viewpoint of wildland fire control, environmentalists, and from the viewpoint of the forest service contractors who serve these diverse groups.
Our forested lands are choking with underbrush, and that is causing real problems when fires reach these areas. Unchecked growth of underbrush also wreaks havoc with ecosystems. At the same time, as a country we are striving to enhance our production of sustainable energy. Clearly something must be done. One solution, says, NC State University Professor Joe Roise PhD, is so clear that were literally tripping over it.
His idea is to harvest the woody debris which is causing such problems, and then use it for biomass power generation facilities. This would rid the forests of the underbrush which threatens the ecosystem as well as posing a fire hazard. The electricity generated would also be cleaner dumping less CO2 into the atmosphere while reducing our dependence on foreign oil. And unlike burning oil or coal, the woody debris is carbon neutral because plants are part of the atmospheric carbon cycle.
Renewable and sustainable energy production is an important element for the 27 states that have Renewable Energy Standards in place as well as for the country as a whole. Each of these states has mandated a different level (percentage) of their energy which must be generated through sustainable means by a target date. North Carolina, where Dr. Roise lives and works, for example, must supply 12.5% of its retail electricity demand through renewable energy by 2021. That means that within just 11 years a significant portion of NC electric demand must be met through solar energy, wind energy, hydropower, geothermal energy, ocean current or wave energy, or biomass resources. Energy efficiency and conservation measures are also permitted to reach the target.
While there are currently numerous co-generation facilities around the country which can accept biomass materials, there are nowhere near enough to provide 12.5% 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 co-generation facilities is to harvest mature trees and utilize the residual, trees, tops and branches. Residual biomass is a byproduct of traditional forest product harvesting and much of the cost of harvesting is supported by sawtimber and pulp. Thus, the residual supply of biomass will go up and down with the demand for lumber and paper, which is not good for supplying energy to a co-gen facility.
Conventional forest harvesting requires crews of workers and multiple pieces of specialized equipment including feller bunchers and whole tree chippers. In addition to the massive amount of capital equipment that is required, there are also numerous workers needed to operate them. Add to this the costs to transport the harvested biomass to a co-gen facility (which would be offset by the price which the facility pays for clean co-gen materials) and it is easy to understand why the geographic range for these activities is so limited. It is only economically feasible to harvest biomass close by the co-gen facilities. And since 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 says Dr. Roise. 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 Dr. Roise had a vision to change that. Armed with his idea, and fortified by his knowledge of the state and national renewable energy portfolio requirements, Joe Roise approached Lebanon, OH based forestry equipment manufacturer Fecon. As luck would have it, their design engineers were already working towards a similar solution. Since then, the two parties have worked together to build and test several variations of the Bio-Harvester technology.
Simple Concept, Difficult Delivery
The basic principle of the Bio-Harvester is simple. Fecon already makes a full line of mulchers which are used across the world 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 to serve as an erosion preventative (and add nutrients and organic matter back to the soil when the mulch decomposes). With the Bio-Harvester, however, the shredded materials are collected and blown into an attached hopper. When full, the hopper is then emptied into a waiting truck for transport to a co-generation facility. Materials are handled once and by a single operator making it simpler and more economical to harvest what was once waste material.
While the concept is simple enough, 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 upwards rotation simplifies collection but at a cost (smaller diameter materials are targeted).
Within the first five minutes of the first test we learned something says Dr. Roise. That was in the spring of 2008 since then, each successive test or demonstration of the equipment has given the team new insights. Those insights have manifested themselves into the second (and third?) generation Bio-Harvester technology. Each change is bringing them closer to the realization of their dream of providing a machine that will significantly increase the range of harvesting biomass further from the co-generation facilities. And that brings them closer to realization of the dream of providing more of the countrys electricity through biomass. Roise also dreams about being able to reduce the wildfire fuel loads in California and have it be profitable.
When the team designed and built the first prototype Bio-Harvester they were striving to produce 10 tons per hour (tph) of shredded green waste which could be harvested by a single operator. The materials had to be of sufficient quality so that they could be sold to co-generation facilities that meant no dirt and a decent mix of materials (not too many fines but no large chunks either).
The machine is designed for materials less than 8-inches in diameter at breast height says Fecon product manager Mark Ferguson. It is designed to gather materials that are not practically harvested by any other method continues Ferguson.
The development team figures that if the machinery is able to process the 10 tph of material, and do so at an average cost per ton of $10 to $12 /green ton, then the concept is commercially viable. All of these targets are built upon the assumption that co-gen facilities will pay $18-28 per ton for materials (the rates at time of initial testing). Naturally, if the price increases over these rates, then the operation has more leniency in terms of its 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 new federal BCAP program will provide matching funds to biomass that producers deliver to a processing facility. These numbers do not take into account the fact that landowners currently pay $500 to $1000+ per acre to mulch brush and hazardous fuels.
Site conditions have an impact on production rates and operating costs. To see how the Bio-Harvester performs in all manner of environments, the development team ran it in a wide range of applications. One was a forest site where we were trying to get control of small diameter woody biomass growth between the rows of a plantation. Another was in the wildland urban interface where we were clearing underbrush close to home sites, recalls Roise. We also worked in a traditional development site, and in a brush dominated ecosystem, and another was all woody brush 20-feet high and densely packed together.
Company officials report that the highest production rates were achieved while performing pre-commercial thinning in a Louisiana pine timber plantation. The long rows allow the machinery to spend a maximum amount of time processing the debris while minimum time is devoted to maneuvering around obstacles. It is not unlike large scale agricultural implements in this regard – long straight row rows are the most efficient way to harvest.
Feedback from the paper mill officials who witnessed the demonstration was favorable. The Bio-Harvester technology certainly cleared the way to allow the timber harvesting equipment unfettered access to their keeper trees.
While pre-commercial plantation thinning allows the highest productivity, there are other applications which might provide greater income potential for the brush clearing side of the equation. Among those, the leading candidate would be fuel load reduction for forested areas.
Operators, knowing that they will sell the shredded product for $18-28 per ton, can live with lower productivity due to the maneuverability issues inherent when moving a large (or more precisely a long) machine through the woods. Company officials said that under these circumstances production may be closer to 8 tph.
The development efforts seem to be paying dividends in terms of production and operating costs. The initial testing yielded rates of approximately 7.2 tons per acre, but after tweaking the collection and blower systems and making adjustments to shoe height and rotor speed, the second generation was achieving 10-15 tph. Company officials are confident that this technology is robust enough to work in the woods because it is, after all, a variation of their other proven woodland equipment.
All Fired Up Over Fuels Reduction Potential
In addition to the potential to develop sustainable energy and reduce dependence on coal or oil, this technology also shows tremendous potential for fuels reduction in our nations forests. The fact that our forests are clogged with underbrush is due to what scientists refer to as the Law of Unintended Consequences.
In the past 60 years or so we have been very successful in suppressing fires says Dr. Roise. Unfortunately that has allowed the growth of brush to continue unchecked creating an unprecedented buildup of flammable materials in the forest. Unfortunately this small diameter woody debris has no commercial value to virtually anyone else in the forest services industry or else it would already be harvested for that commercial purpose. So the buildup continues and as it does, so does the chance for a catastrophic fire.
That is because a 20-foot tall section of overgrown brush, when topped with a 20-foot flame (not uncommon in forest fires), can easily spread the fire to treetops which is the fastest way to spread forest fires.
So eliminating this nuisance is important. Eliminating it while using the materials for a beneficial purpose is precisely why Dr. Roise and the Bio-harvester team are so excited about their success here.
Harvesting Small Diameter Woody Biomass Improves Ecosystems
Another unintended consequence of the growth of underbrush in our forests is that it is dramatically altering ecosystems. Take the endangered Red Cockaded Woodpecker as a case in point. When forest fires would naturally maintain the growth of brush, the red cockaded woodpecker was relatively safe in its nests. As brush grows ever higher, though, their habitat becomes more undesirable for a variety of reasons, such as natural predators like snakes can slither through the brush, giving easy access to the woodpeckers nests. Disappearing habitat has catapulted the Red Cockaded Woodpecker onto an undesirable list that of endangered species.
One 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. Habitat for a native bat was successfully re-established with a test in Kentucky. So clearly, the technology shows promise from an environmental viewpoint as well helping to return ecosystems to their natural state and ensuring the biological diversity of the forest creatures.
A Winning Proposition On All Fronts
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 power to the grid. Up to now a stumbling block has been the supply of clean green waste to burn. One reason for a shortage of supply is that operators using multi-person crews are effectively tethered to a leash, a short distance from the co-gen facilities.
But this new technology aims to significantly increase that range. If a single operator with a single machine can profitably process materials for co-generation or wood waste power plants, surely that will impact the supply side of the equation. And when that happens, it will mark a dream come true for Dr. Roise, Mark Ferguson, and the development team that has shepherded this technology from concept to completion. More importantly, it will be an example of turning trash into treasure a treasure (clean, sustainably generated electricity) that we can all enjoy.