Biomass Feedstock Production and Provision: Overview, Current Status, and Challenges - Engineering and Science of Biomass Feedstock Production and Provision - page 8

in Europe, is the self-propelled forage harvester (SPFH). With an SPFH, the biomass
is harvested and immediately chopped into smaller particles, which are then loaded
onto a wagon moving alongside the SPFH.
For the energy crops, a two-cut system has also been proposed. In this system,
the crops are harvested once midway into the growing season and again at the end
of the season. It has been argued that such a system will increase the total biomass
output. However, studies confi rming this advantage have been limited. Moreover,
high moisture content of the biomass and the nutrients removed along with the bio-
mass harvested during the fi rst cut will be problematic. Therefore, as per the current
understanding, a single-cut system will be employed.

1.3.3 Storage

The bales would normally be stored at the edge of the farm in the open. The ground
may be paved or it may consist of gravel pad. It is being argued that setting up a
covered storage facility on the farm may not be cost-effective given the low bulk
density of the biomass. If the expected duration of the storage is long, or if the
weather is not very conducive (high rainfall, stiff winds), then the bales might be
covered with tarpaulin. The moisture content of the material at the time of harvesting
and baling may also have an impact on the storage method. The use of an SPFH for
harvesting creates problems for storage because the chopped biomass cannot be
stored in the open. Closed structures, such as a shed or a silo, will be required for
long-term storage of chopped biomass. An SPFH, therefore, may be preferred only
in cases in which the chopped biomass is directly delivered to the conversion facility.
The idea of storing of biomass at dedicated storage facilities is not widely accepted
at this stage. There is, therefore, an increasing interest in incorporating some form of
preprocessing along with storage at these facilities. These are often referred to as
storage and preprocessing depots or centralized storage and preprocessing facilities.
However, such facilities do not currently exist, even for agricultural residues.

1.3.4 Transportation and Preprocessing

The transportation of biomass would be by road using trucks and trailers. It is
believed that the maximum feasible collection distance of biomass for a biorefi nery
would be about 150-200 km. Beyond this distance, the cost and energy consump-
tion associated with transportation will increase substantially. Therefore, truck
transportation would be most appropriate because it provides the necessary fl exibil-
ity. This fl exibility is essential since it allows collection of biomass from diverse
locations, in relatively smaller quantities, and its delivery at the biorefi nery. There is
some concern about the possible traffi c congestion at the biorefi nery site given the
number of truck deliveries required every day. This might have implications on the
site selection as well as the size of the biorefi nery.