Transportation - Engineering and Science of Biomass Feedstock Production and Provision - page 152

6.4.1 Truck Transport

Green biomass such as sugar cane is perishable and needs to be processed ideally
within a few hours after harvest. Therefore, in this case, short-distance truck transport
is effective but not necessarily efficient. Since green biomass can have a moisture
content of over 50 %, the weight limit is typically reached before the volume limit.
Flatbed trailers are often used for bale transport, and by taking into account vol-
ume and weight limits, the maximum density of the bales is 223.5 kg m −3 [ 35 ]. This
value is achievable using modern baling technology.
Transloading is defined as the operation that moves goods from one form of
transportation to another such as from a truck to a railcar or barge or vice versa.
Each transloading operation can incur losses and damage, therefore the logistics
system needs to be designed to minimize the number of transloading operations.
Transloading of biomass in bale or containerized form can be achieved using tradi-
tional equipment such as cranes, forklifts, stackers, and bulldozers. Pelletized mate-
rial can be conveyed using belts, augers, and chutes, while powdered material can
be conveyed pneumatically.
Specialty trucks such as concrete carriers and dump trucks have an exempt status
in terms of weight limit, but biomass is not likely to reach densities that warrant the
use of such equipment.

6.4.2 Rail Transport

Short-distance transport of biomass using trucks is well suited to the achievable
density of bales. However, the rail to truck fuel efficiency ratio of gondola-type
railcars (such as those used for coal transport) ranges from 2.3 to 4 [ 39 ], making rail
transport more efficient than truck transport. This is especially valid for long-
distance transportation for which rail transport has lower operating (variable) costs
than truck transport; this reduction offsets the higher capital (fixed) cost associated
with rail transport. For straw and corn stover, in North America, the minimum eco-
nomic rail shipping distance (MERSD), the point where rail transport becomes
more economical than truck transport, is 170 km. The value for boreal forest harvest
residue wood chips is 145 km due to its higher density [ 40 ].

6.4.3 Water Transport

The same issues associated with rail transport are present in water transport using
barges and even ocean-going vessels. Any material in bulk form can be transported
using railcars or ships, but only efficiently if the bulk density of the material is such