Foraging for Efficiency
Though short-rotation woody crops such as willow and poplar boast a variety of characteristics that make them attractive as potential bioenergy feedstocks, the real challenges dwell within harvesting and transport logistics, a segment of the supply chain that has taken collaboration from government, academia and equipment suppliers to navigate, and work is still ongoing.
One of the biggest hurdles in mechanizing the harvest of woody biomass crops is variation in cultivation. Doug Otto, New Holland’s senior manager of specialty business units, didn’t hesitate with an answer when posed with the question. With poplar and willow just emerging in the U.S. as commercial bioenergy crops, researchers and growers are still writing the book of best practices, and New Holland is largely serving as a contributing author.
“First, these crops have to be grown in appropriately sized lots so that the machines can get in,” Otto says. “If the rows of trees aren’t planted appropriately, then we suffer considerable machine damage. The harvester really wasn’t intended to be running down rows of trees, and there isn’t enough shielding to avoid the units taking on damage. As we have moved forward with mechanized harvesting, growers have changed and adapted to the kind of cultivation these [crops] require. In the beginning, that was a real challenge.”
Otto has been on the forefront of New Holland’s efforts in working with clients to test how the company’s machines work in fields of short-rotation biomass crops, and tweaking them to maximize performance according to each specific crop’s characteristics.
Another challenge that Otto mentions has been the time of year these crops are harvested. “It’s muddy, so there are issues trying to drive a large machine down in the mud, issues that generally aren’t present when you’re harvesting other kinds of crops,” he says. “Sometimes you can do it when the ground is frozen, and that helps.”
Machine-wise, the actual chopping of the biomass crop—i.e., willow—isn’t difficult, according to Otto, but manipulating the tree so that it’s properly fed into the forage harvester can be, as these trees do not always grow in the desired direction.
Essentially, the forage harvester is a giant paper shredder, Otto explains. “The base unit—the forage harvester—is a giant chopper,” he says. “It has a rotating drum inside that is equipped with rotating knives. The header—the unit in the front—is a machine that is equipped with saw blades at the bottom, which cut the tree off at the ground, and then presents it to the chopper in such a fashion that it can be pulled horizontally into the cutter head. A feed roll pulls materials in, where they are sliced into small pieces.” Beyond the cutter head is an accelerator, or blower, that forces the crop out of a pipe into a wagon.
Success By Trial
Since State University of New York’s College of Environmental Science and Forestry landed a $3.5 million U.S. DOE grant in 2009 to fund an ongoing project that is focused on developing ways to reduce the cost of delivering biomass for refinement, New Holland Agriculture has gone the extra mile to assist. Not only did the company provide SUNY with a FR9080 self-propelled forage harvester with a 130FB coppice header for use during the project, which is focused on short-rotation woody crops like willow—but the company has actually been involved with SUNY since 2004 when the project was first conceived, and worked with SUNY to acquire feedback on what the machine was doing in the field and details on failures. These challenges were taken to New Holland’s Innovations Team, where some different solutions were designed, and, years later, resulted in permanent equipment modifications. “From this real word experience and back and for with them, we drove several changes into the units—it improved the performance of the units that we were selling in Europe as well,” Otto says. “In a niche market like that, it’s what we do. The coppice head was actually initially designed for use in Europe, where the market is much more developed. We took that design and started testing it here with SUNY because of the emerging willow market, and we found that we needed to make some changes.”
Those changes included saw blade modification, in-feed changes and hydraulics tweaks. As Otto points out, saw blades are fairly unique for various wood crops. “When you’re using them to cut poplar, different blade properties work better there than they do with willow.”
Changes related to crop guides affected how the trees are fed into the machine after being cut off. “Some of these [malfunctions] happen because of the differences between species of trees, but in the end, we found that the changes we made were good for everyone,” Otto says. “We also made some hydraulics systems improvements—some changes with feed rolls inside the header—it’s all about getting better feeding from when you cut off the crop to getting it into the chopper.”
SUNY’s research project is still ongoing, and though New Holland is no longer active on-site working to engineer new solutions, it continues to support SUNY’s efforts through the donation of the machine and support for the unit itself. New Holland is also involved in a similar, less-formalized project in Boardman, Oregon, with Greenwood Resources, which uses poplar, a crop that Otto says has integral differences in terms of final product, but isn’t much different than willow in terms of harvesting. “We don’t necessarily have to make changes to the machine for one or the other—it comes down to how they cultivate it, which is what provides the differences. The same header can be used to do both.”
While universities and companies continue moving forward in commercial growth of woody biomass crops, New Holland plans to ride along and assist. “[Woody crops] is a new thing that hasn’t taken off everywhere, so we’re trying to help drive the market,” Otto adds. “We want to show that we can produce equipment for traditional ag uses, but also open up the opportunity for customers to use these machines for alternative means to help pay off the investment.”
Author: Anna Simet
Managing Editor, Biomass Magazine