Wood Biomass Harvesting: Delivering Efficiencies

Innovations in biomass harvesting, hauling and transport are reducing raw material costs for end users. From large-scale harvests to small-scale logging, foresters are pairing smart technique with novel equipment to get jobs done more efficiently.
By Ron Kotrba | May 09, 2020

Feedstock costs for biomass power plants and combined-heat-and-power systems represent a significant percentage of operational expenses, and harvesting, hauling and transportation costs constitute a vast majority of feedstock costs. Innovations upstream, therefore, may ultimately play a big role to reduce the cost of biomass to the end user. “That makes perfect sense,” says Tom Gallagher, a professor of forest operations at Auburn University. “The problem is, there are so many limitations on what we can do. Biomass is a low-value commodity. The market is significantly worse than it used to be.” Gallagher says in the “heyday,” biomass deliveries were fetching $28 a ton, even for “dirty” chips. “Now they’re lucky to get $20,” he says. “They can [barely] afford to make it for that, so there are limitations on what efficiencies can do.”

One efficiency Gallagher sees as crucial to lowering costs is moving more biomass at once. To do this, trailers can be adapted to accommodate greater loads. But first, regulations must be updated.

“We have great roads in the U.S., but we also have the lowest weight vehicles in the world,” Gallagher says. “In Europe, the weight limit is 132,000 pounds. We are at 80,000 pounds. Where does that limit come from? It was chosen in 1953 with the launch of the interstate system when we had bias-ply tires, trailers with no suspension, and drum brakes. Now we have steel-belted radials, trailers with airbag suspension systems and airbrakes.” Gallagher says discussion is ongoing in Washington, D.C., to eventually permit trucks to haul more weight. If and when this happens, it could be a gamechanger for the wood and biomass industries.

Gallagher says Auburn has been part of a larger USDA Forest Service grant project with other schools, including North Carolina State University and the University of Tennessee, to investigate more efficient movement of biomass. The study involved utilizing timber processing depots to relocate the processing of tree limbs and crowns from in-woods logging sites to a central location. “By processing all of the timber at one central location, researchers believe they can optimize the amount of biomass fuel material yielded from each tree by reducing the amount of usable biomass fuel material that is left behind on the harvesting site, and by reducing the ash content of the biomass fuel material to produce a higher-quality energy fuel product,” the researchers write. However, for this to work, unprocessed whole trees must be delivered to the site, which requires trailer modifications.

Two designs were conceived for the modification of the log trailers: a swinging guide design and an extendable bolster design. Total weight, load force analysis, ease of attachment and detachment, modification cost and overall feasibility were considered before choosing one modification over the other for payload capacity utilization testing. The swinging guide design was chosen, and Gallagher says UT and NCSU are still running the economics of the study. “We’re on the tail end of that study right now,” he says. “I’m a harvesting guy, a forester by trade. My part of the picture was to develop the trailer design to handle whole trees, tops and all. This was one way we feel is the best opportunity for efficiency gains across the system. One could argue it allows for the hauling of biomass down the road for free, while transporting pulpwood, saw logs or whatever. Personally, I was not a big fan of the depot idea. [NCSU and UT] came up with that, and they’re having a hard time making the economics work. Biomass is a low-value commodity, and it’s economically challenging to move once, let alone twice.”

Hydex LH45
U.K.-based Hydex Solutions Ltd. says its LH45 Log Hauler with Trailer has been specifically designed to transport harvested logs easily and safely from the stump or logging site to a processing area. “Due to the high flotation of this type of machine, the LH45 can run infield in areas of timber harvesting operations saving material handling and processing operations,” reads the spec sheet.

The Hydex LH45 is built on the Caterpillar 745C long wheelbase chassis utilizing the Caterpillar C18 engine rated at 496 horsepower, and it features a top speed of 30 miles per hour for faster cycle times. The company says its automatic traction control eliminates wheel slip for maximum traction and increased productivity. The LH45 trailer bunk dimensions allow safe transportation of maximum harvested loads, according to Hydex. The trailer’s sliding hitch setup allows for up to a 50-degree turn while loaded, and the LH45 combination truck and extension trailer can accommodate logs up to 60 feet long.

Incorporated into the LH45 is the Hydex Weight Monitoring System, which weighs the loads on the LH45 and trailer separately with load cells. An in-cab display shows weights for the LH45 and the trailer individually, and combined. This information can be printed using an in-cab printer and be stored on the LH45’s heavy duty USB storage key. Hydex says this saves operators time and money by eliminating the need to use a weigh bridge, while increasing safety at the site.

“The LH45 came across from knowledge of the market, our good friends, and once the idea was made, we started to construct the machine,” says Luke Plume, sales manager with Hydex. Plume tells Biomass Magazine that Hydex began production of the LH45 three years ago. “We saw a gap where we could save companies a lot of money in operating costs,” he says.

According to Plume, the largest benefit provided by the LH45 over conventional forwarders is the strength of the machine. “Our competitors have real problems with the trailer bending when overloading the machine,” he says. “The machine we have put together is a cut above the rest. We tested our equipment, against other manufacturers for quality and we believe we are the best for quality and price.”

When asked how innovations in harvesting, hauling and transport by companies like Hydex ultimately reduce the cost of biomass to the end user, Plume says, “Our aim to reduce costs for the biomass end customer lies in the forest. The costs of chopping down the trees, logging to roadside and to the sawmill is very expensive, if done wrong. This is where Hydex comes in with our log hauler to help, as it takes the responsibility of multiple machines.”

Columbia Timber Co.
Jib Davidson is a certified forester. In the late 1980s, he and another forester, Norman McRay, founded Columbia Timber Co. The firm is multifaceted and encompasses land management, logging, real estate and, more recently, biomass harvesting. Today Columbia Timber has three biomass crews. “We started harvesting biomass when the biomass power plant was built in Gainesville, Florida,” Davidson says. The Gainesville Renewable Energy Center—one of the largest biomass power facilities in the U.S. at more than 100 MW of generating capacity—began operating in 2013. In 2017, it was sold to Gainesville Regional Utilities for $750 million. “We are currently their largest supplier of biomass,” Davidson says. “It’s been good business for us, and for them.”

Columbia Timber’s clients are varied, and with Davidson and McRay’s land management and real estate development focuses, moving into the harvesting of biomass was a natural fit. “Before the land goes on the market, we harvest the biomass by cleaning up the property of oak thickets and brush to make it look nice,” he says. “The biomass plant benefits—they get a cheap source of fuel—we benefit, and the seller benefits because it increases the value of their land, and it looks better.”

Originally, GREC had its biomass fuel procurement divided into two baskets—urban and forestry wood, according to Davidson. “We were on the forestry side of things,” he says. “Because of our land management practices and timber procurement, we produce treetops, limbs and branches that can go into the chipper and be sold as biomass fuel. We’re sending the roundwood to the local pulp mills and we’re providing site preparation for landowners, who no longer have to pay the costs of raking, piling and burning the biomass residues. We take all that stuff.”

Some common forestry practices make foresters like Davidson cringe. “One of the worst things we do as foresters when we’re logging is, we have a ramp and we take the skidder blade and push all the debris into a giant pile,” he says. “What this does is push all the topsoil into a giant pile. We shouldn’t be removing topsoil. This should stay on the ground. So, when we (Columbia Timber) remove tops and branches, we don’t produce big piles by the skidder. And in the next phase, during site prep, we don’t need a rake, as we do no piling or windrowing and, henceforth, no burning, and we leave the topsoil where it is. We may leave behind small twigs and branches, which makes this a better site from both sustainability and nutrient retention perspectives. That’s a big deal if you’re a forester.”

The new name of Gainesville’s biomass power plant is the Deerhaven Renewable Generating Station, and Davidson says if running at full steam, the facility can consume 1 million tons of biomass a year. “Currently we take about 5,000 tons a week, or between 200,000 and 250,000 tons per year,” he says. “They run an ash content test on every load that goes into it, and of course a major component of ash is sand, and we’ve never once been dinged on a single load for high ash content.”

All of Columbia Timber’s equipment is operated in the woods. The company relies on chippers from Bandit Industries Inc. “We settled on Bandit because of their service, and we feel they do a good job with a minimum amount of complexity—the simpler, the better. As soon as you bring in any complications, the crews begin to have problems, and we don’t want that.” Columbia Timber owns and operates three inline horizontal whole tree chippers, one 2590 model with a 22-inch capacity and two 3590 models with 36-inch throats. “We did production studies with our 3590,” he says. “We got ourselves in position with perfect conditions—the wood lined up and the loader man rocking—and we can blow an entire van (trailer) in eight minutes. That’s 28 tons. Clearly that is ideal conditions, but more realistically, we can do four loads an hour per chipper. We hot load. We can’t drop the trailer—that takes too long.”

Loading 28 tons of biomass chips into a trailer in eight minutes seems quite efficient, but when Davidson is asked how innovations in harvesting, hauling and transport by companies like his ultimately reduce the cost of biomass to the end user, he says, “I wish I had a great magic wand to create things to be more innovative. I go to association meetings, events and check out other crews to see what they do, and I’ve not found any great new wonder pill.”

Davidson says if done right, a logging or biomass crew can be run with five people. This includes one to two skidder operators, an operator manning the “cut down machine” or feller buncher, a deck hand, and a loader operator. “The loader operator loads the roundwood and runs the chipper,” he says. “The chipper is operated through remote control by the loader operator. He’s doing a lot throughout the day, and it’s important to do the job right.”

The chipper is controlled remotely via Bluetooth technology. “The more computerized Bandit makes its chippers, the happier we are,” Davidson says. “The loader monitors the chipper, so if he can load, chip and log separate at the same time, we’ve got a great situation.”

Remote control chipping is “common nowadays,” Gallagher says. “It’s not hard to have a remote-control chipper, but it still requires a manual start. That technology is 10 to 15 years old. Back in the day, when people were doing more biomass harvesting, a lot of crews were running these.”

Columbia Timber only utilizes aluminum trailers since they are lightweight. “We wear out standard trailers quickly,” Davidson says. “We don’t want steel trailers. We like the lightweight aluminum trailers.” The company owns the trailers and has historically contracted haulers who supply their own trucks.

“We tried to depend on independent contract haulers because it keeps us out of the trucking business,” Davidson says. “We’re not truckers, we’re foresters.” The problem, he says, is reliability. “If we can come up with a solution to the trucking problem, that’d be wonderful,” Davidson says. “But we recently acquired three trucks, owned and operated by Harrison Logging. We formed a partnership with them. Maybe it costs more to have these trucks, but on the other hand, with Harrison employees and Harrison trucks, because Harrison Logging manages our entire logging crews, perhaps we can do better with reliability.”

Gallagher has reached out to Davidson and plans to monitor his operations as part of a new study involving a number of universities and regions. “Jib’s making it work, but he recognizes he can’t just harvest biomass,” Gallagher says. “He’s harvesting stands, taking off the sawtimber and pulpwood, and to finish up the job, he throws the residuals in the chipper. We’ve been doing that for a long time. In the mid-2000s, this was very popular. Between the Great Recession and cheap natural gas, the markets are all gone. But there’s a strong market in Gainesville with the biomass plant.” 

One advantage for Columbia Timber, Gallagher says, is “he makes his job look nice. When he’s done, it’s a bare site—a clean field. Most loggers without biomass markets leave piles of limbs and tops, and it’s worthless to them so they light a match and it all goes away. He’s got a market for that material, and it looks like a ballpark when he’s done. Most others can’t do that.”

Ongoing Research
About a decade ago, Gallagher was instrumental in the development of a trailer-mounted slash bundler. “We put together the machine and it was successful, and once it was completed, the biomass market collapsed,” he says. “We can’t justify the costs associated with that—maybe if the market returns. But now, it’s a dead issue.”

A new project Gallagher is currently working on is a unique feller buncher. “We want to put one of those on a small boom-type machine that can efficiently go down, reach into the stand and cut small-diameter trees for a small skidder to take out,” he says. “We put this on a boom machine, so it doesn’t have to be driven around so much. And we want to use smaller equipment.”

Loggers typically focus on economies of scale, Gallagher says, but with forest fragmentation increasing as older-generation landowners bequeath parcels of land to children divided up into smaller segments, it becomes harder for loggers to justify activity on small, segmented lands. “They don’t want to move but once a month, so the loggers don’t want to [touch] these smaller-acreage stands,” he says. “If we develop an efficient way to cut and remove smaller volumes using smaller machines, this gives landowners the option to grow timber, and small-scale harvesting can be employed. It’s a limited-area feller buncher that allows more nimble movement.” 

Gallagher is a big believer in small-scale harvesting. Another idea of his is to change silvicultural practices, particularly in the Southeast. “Once a lot is clearcut, instead of replanting with 500 trees per acre, plant 1,000 per acre,” he says. “Now, instead of coming in after 13 years and harvesting the pulpwood trees and leaving 200 standing for another 10 years for sawtimber, after eight years you could go in and harvest half for biomass, leaving 500 trees for pulpwood and timber. You could get a biomass commodity off the same track of land in less time.”

The nimble feller buncher Gallagher is developing could help make this vision a reality.

Ag Biomass
The world of biomass is often dominated by woody materials, but significant gains have been made over the years in harvesting, hauling and transport of agricultural residues and dedicated energy crops. Genera Inc. is depending on those innovations to make the economics work for its new ag fiber facility under construction right now. The company closed financing in July and shortly afterward began retrofitting a brownfield facility near its headquarters in eastern Tennessee. The plant will consume 50,000 tons per year of switchgrass and sorghum to produce ag fiber, half of which will be sold into the market as nonwood fiber, while the other half will be molded onsite into various sustainable containers—compostable and biodegradable bowls, plates, takeout containers and consumer packaging. The pulping technique employed is different than the Kraft process. “It’s more mechanical than chemical,” says Sam Jackson, vice president of business development for Genera. “It’s a sustainable process that uses dramatically less water and energy than the Kraft process.” Genera’s ag fiber facility is expected to come online by end of year.

“The supply chain is at the heart of what we do,” says Jackson, who is also a forester. “Transportation eats you up. It’s a challenge. Over the past 10 or 12 years, we have participated in grant-funded research on supply chains, how to improve harvesting at the field, how to improve the logistics of overall systems, and how handle the material in more bulk format. There has been significant improvement made over time, but there’s always still gains to be had. By no means is it a perfect system, but there have been lots of improvements.”

The agronomic understanding of dedicated energy crops and residues has improved significantly, Jackson says. “Things like how to best utilize nutrient inputs to minimize cost and encourage good growth for high yields,” he says. “The more yield per acre, the more effective our harvesting is.”

Notable gains have also been made in harvesting by ag equipment manufacturers. “Round and square balers, those have come a long way,” Jackson says. “Today, balers pack the bales at much higher densities—10 pounds per cubic foot, and some are getting up to 15 pounds. When you improve the density, you improve logistics. For our plant in eastern Tennessee, we want to use mostly round bales. This isn’t optimal for transport, but it’s good for storage. They shed water, so when they’re out on the field edge, there’s not a lot of degradation. Square bales must be covered. Round bales fit the climate and equipment people already have here. In other areas that have lower rainfall, large square bale systems may fit better.”

Despite the appreciable gains in ag biomass understanding, growth, harvesting and hauling, Jackson says there is more to be had. “We’ve been at this a short period of time in the grand scheme of things compared to corn or beans, where they’ve had decades of breeding and selection,” he says. “There’s still a lot we can do with the crops themselves to increase efficiencies.”

Another key area that can be better addressed is enhancing long-term storage of ag biomass to prevent degradation. “This is biological material, so when you store it, you’re going to lose quality and dry matter material—even in the best scenario,” he says. “So, we need to look at what we can do to improve the lifespan or durability of this feedstock through storage, such as adding preservatives to extend shelf life.”

Jackson says preliminary work has been done to this end, but the concept has yet to be commercialized for biomass. “If we can extend the shelf life, this provides the downstream user flexibility.” He says alfalfa is sometimes treated with chemicals to preserve the integrity of the feed for overseas shipping. “We can use something like that in biomass feedstock to give us longer shelf life, so the material will be more durable in open storage,” he says. “There’s a significant cost to using tarps or covered, open buildings. If we can maintain preservation uncovered, this would reduce the overall cost.”

Author: Ron Kotrba
Senior Editor, Biomass Magazine