By Charlie O’Brien
Baling, storing and transportation logistics may seem
like run-of-the-mill techniques to today’s agricultural producer. But the steps
from the field to the biorefinery are some of the most important in the biomass
supply chain, potentially making or breaking a producer’s crop.
When it comes to harvesting, producers need to weigh the
economic costs with the logistics of what kind of bales they want to produce:
round or square. Both bales’ designs feature unique positive and negative
attributes.
Traditionally the 5-by-6 foot round bale has been the
most popular bale shape for biomass as it is the cheapest to produce, the
easiest to feed livestock with and its round shape helps shed water. Less
popular square bales may offer some practical benefits, both for storage and
transportation.
“We are trying to reconfigure round bales to make them
more logistically efficient,” said Kevin Shinners, professor of agricultural
engineering at the University of Wisconsin-Madison and co-project director for
CenUSA Bioenergy. “By using a square bale we increase the bale’s density, and
the shape is easier to transport.”
Another CenUSA Bioenergy researcher, Stuart Birrell,
professor of agricultural and biosystems engineering at Iowa State University,
sees bale transportation as an economic issue. When typically transported on
flatbed trailers round bales compared to square, are less efficient. Their
curved shape creates gaps, wasted space during transit. Birrell suggests that
if round bales are continued to be used, the industry should consider adopting
specialized trailers from the cotton industry designed specifically to hold
large, 8-by-8-foot, round bales.
To increase transportation efficiency in the biomass
supply chain, both Birrell and Shinners believe increasing density is a key
factor. Round bales are not nearly as dense as square bales, thus causing
producers to not use their trailer’s entire weight limit. In the past, Shinners
has experimented with large cotton balers that create 5,000--pound bales, a far
denser product than the 5-by-6 foot bales that weigh about 1,800 pounds.
“Round bales are also cheaper to produce because its
machinery is cheap, but they create a storage and transportation issue. We just
have to find out if square bales’ benefits can outweigh its costs,” Birrell
said.
In addition to baling logistics, producers need to factor
in storage of any biomass material. Both types of perennial grass bales round
or square, are able to be stored outside rather than indoors. This additional
advantage is due to the crop’s thick natural thatch that sheds water, allowing less
amounts of biomass loss.
As biomass in the energy sector progresses, new
techniques and practices will be developed to streamline costs and maximize the
economic competitiveness of the biofeedstocks. But it’s unlikely that there
will be a one size solution to post-harvest logistics.
“It is hard to make a profit with just one kind of crop. You’re
looking at all different kinds of biomass crops and it will take all of them to
make this a successful industry,” Birrell said.
