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December 2003 January 2004


Using slash for power

Timberjack is introducing a mobile wood slash compactor, which delivers benefits in fire prevention and produces fuel for power generation, into the Canadian market.

By Tony Kryzanowski

Timberjack’s energy wood harvester is designed around the company’s basic 1410D short frame forwarder, with a special rear frame design.

Every year, thousands of hectares of merchantable timber and—as was seen this past summer in BC’s Southern Interior—even homes are being lost to wildfires. However, the Canadian forest industry now has a new tool to remove slash from the forest and help prevent forest fires. It’s called an energy wood harvester, a piece of equipment that essentially is a mobile wood slash compactor and bundler. The technology was developed and patented by the Timberjack division of John Deere, and has been working in European forests for the past four years. Over 20 units are currently at work in Scandinavia, Spain, Italy and the United Kingdom. In addition to helping prevent forest fires, the use of the energy wood harvester could eventually provide loggers with another income stream. Slash normally piled and burned is already finding a market as feedstock for biomass power generating plants and in the manufacture of biofuels.

The biomass bundles or “logs” manufactured by Timberjack’s energy wood harvester also have potential in erosion control and in fish habitat rehabilitation programs. Whether the energy wood harvester can be run profitably, however, remains to be seen. Alberta logger Robert McRae recently attended a demonstration of the energy wood harvester. He owns Ro-Da-Cor Enterprises, a third generation logging company that was among the first to adopt cut-to-length technology in North America.

Once enough slash material is compacted to achieve a set diameter, a bundling ring spins twine around the “log” to hold the compacted material in place.

McRae logs for Weldwood of Canada in Hinton, Alberta. He says he has been interested in slash bundling technology ever since it became available. He adds, however, that it is really up to the builders of biomass power generators to establish the facilities, and make contracts available for delivery of slash, before contractors can reasonably be expected to invest in an energy wood harvester. Purchasing an energy wood harvester requires an investment of about $600,000. “With power de-regulation here in Alberta and the adoption of the Kyoto agreement, I would say that these are good indications that developing biomass energy plants should take off,” he says. “But the main players like the Weldwoods and Canfors have to push it.” Industry experts who have researched wood energy harvesters say that it could make money in niche applications. For example, within a 100-kilometre radius of an existing biomass power generating plant where there are significant volumes of slash available.

In Finland, slash is sometimes transported from twice that distance, however. Or it could be put to use in areas where large companies or the government redirects a portion of existing forest fire prevention funds toward supporting the use of this new technology as an alternate approach to fire prevention. There are discussions taking place in Alberta regarding an initiative called the Urban Wildfire Interface, where a concerted effort may be made to reduce slash around communities as a fire prevention method. McRae says that there are other well-known and reputable suppliers of slash accumulation and compacting equipment in addition to Timberjack. “However, looking at this piece of equipment and knowing where Timberjack comes from,” says McRae, “I think this energy wood harvester will do the trick. It’s basically electric over hydraulic, and this type of equipment has come a long way over the last 10 years.”

While new to Canada, over 20 of the Timberjack energy wood harvesters are currently at work in Scandinavia, Spain, Italy and the United Kingdom.

Longer term, legislation restricting or banning slash burning could have a major impact on how eager contractors will be to embrace this new technology. They may be forced to find alternate ways of disposing of accumulated slash, and the energy wood harvester may be the answer. Timberjack advanced harvesting team leader for western North America, Dave Wellman, says that interest from people at demonstrations has been phenomenal. They have also attracted representatives from across a wide spectrum of groups. “There have been a lot of people out there that I didn’t expect to see,” says Wellman.

Timberjack’s energy wood harvester is designed around the company’s basic 1410D short frame forwarder, with a special rear frame design. Additional software has been added to the forwarder’s standard Total Machine Control (TMC) system to operate the functions needed to compress and bundle slash. “We’re taking what is normally considered a waste product and somewhat of a fire hazard, compressing it, and making a giant fire log or fuel log that can be burned in co-generation plants that produce electricity,” says Wellman. The energy wood harvester solves the transportation problem of packaging the fuel at the harvesting site in such a way that bundles can be easily stored until needed, and economically transported directly to biomass power plants and chipped or crushed when needed.

The equipment operator uses a grapple to retrieve slash and place it at the receiving end of the energy wood harvester’s compression system. The slash goes through a series of compression processes. The first consists of four rollers, then a fixed compacting unit, and then a third compactor that moves with the bundling ring that contains rolls of twine. Once enough material is compacted to achieve a set diameter, the bundling ring spins twine around the “log” to hold the compacted material in place. When the bundle reaches its programmed length at the discharge end, it is automatically cut off and the process starts all over again. The computer program can be adjusted to change the length of the bundle, the number of twine wraps and the distance between wraps. “It’s possible to manufacture a log every 1.5 minutes if you have enough material and a skilled operator,” says Wellman. “The machine is fast enough to do that.” In Finland, they average between 20 and 30 bundles per hour, depending on the skill of the operator and amount of material available. In many areas where energy wood harvesters are in use, a forwarder gathers the fuel logs and loads them onto standard shortwood log trucks for transport.

Each fuel log weighs about 453 kilograms (1,000 lb.), depending on the dryness of the material. From an energy standpoint, burning the chips derived from 16 of these bundles will provide the electrical needs for the average Canadian family for a year. Looking at it another way, two fuel logs deliver the equivalent energy of a barrel of oil. The energy wood harvester also delivers a number of environmental dividends. The first is reduced soil compaction in the cutblock. “In a lot of areas, the slash is piled with an excavator or log loader, then burned,” says Wellman. “That means more travel on the site and more ground compaction. This machine has very low ground pressure.”

The second environmental benefit is that power is being generated from a new, renewable resource, which will add to the overall amount of power available and reduce the possibility of brownouts and blackouts. Only two-thirds of the slash is removed from the site. One third of the cones and branches are left in the cutblock to leave genetic material behind, to encourage a certain amount of natural regeneration, provide nutrients for the soil and also for wildlife habitat. Finally, the process of gathering, compacting and bundling the slash into fuel logs is considered carbon dioxide neutral from a global warming standpoint.

In other words, no more carbon is released into the atmosphere in the gathering, bundling, and burning process than a tree absorbs during its life cycle. Prevention of wildfires, which can release a considerable amount of heat and carbon into the atmosphere, is also another positive step in the effort to reduce global warming.

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