Environmental Engineering Reference
In-Depth Information
rate cost and the lost value cost due to deterioration of biomass during storage. This is where
the biorefinery plant can use an intermediate depot to avoid such costs. However, offsetting the
advantages of using an intermediate depot is the fact that the biomass will need to be loaded/
unloaded from the vehicles multiple times, and special loaders/unloaders designed for different
vehicle types may be required. The types of loading/unloading systems and the time spent loading/
unloading vehicles will ultimately affect transportation costs (Allen et al. 1998; Sokhansanj and
Fenton 2006; Eksioglu et al. 2009; Frisk et al. 2010).
An integrated, uniform format solid feedstock
supply system would address many of these concerns (Hess et al. 2009).
7.9 Paths ForWard
This chapter reviews biomass harvest, storage, and densification technology; logistics system char-
acteristics; and the inherent tradeoffs that underscore the importance of a holistic system view
of logistics management. Although it is important to have innovative, effective technology and
appropriate strategies at the unit operation level, it is also equally important that these individual
operations interact as a whole. The objective has to be to operate the whole system effectively,
not just the individual parts. In this respect, Coyle et al. (2008) accentuate an important aspect of
logistics management: that logistics decisions must be made with an understanding that multiple
levels of optimality must be considered and that some levels of suboptimization may occur. An
organization may achieve organizational optimality by balancing various elements of logistics
systems (e.g., harvest and transportation versus warehousing and inventory and customer service)
as well as against other subsystems of the organization (e.g., logistics versus marketing, production,
and finance). At the next level, the organization may achieve supply-chain optimality by trading
off the effects that its decisions have on the other members within the supply chain, and vice versa,
to optimize the operation of the entire supply chain. This will be particularly important in bio-
mass supply chains, which are likely to be highly decentralized with limited vertical or horizontal
integration. Finally, operated in a society, a supply chain has imposed upon it, by society, various
constraints under social, political, and economic influences. For the biomass industry, this would
clearly include environmental sustainability and rural economic development, but also issues of
environmental health and social equity. At this level of societal optimality, decisions must be made
that optimize the organization and the supply chain subject to the requirements of society. Given
the multiple levels of optimality that are critical to logistics decisions, it is clear that each success-
ful organization in a biomass supply chain must understand all of the constituencies affected by its
activities and then optimize at the levels that are appropriate.
Sustainability criteria will be an increasingly important factor in this optimization, requiring
source identification and chain-of-custody documentation throughout the supply chain to satisfy
societal and organizational goals and constraints. Voluntary certification programs are developing
multidimensional criteria and standardized metrics, whereas governmental agencies set their own
criteria to meet mandates for low-carbon fuels. As specific sustainability targets emerge, they will
drive innovation to reduce energy losses, greenhouse gas emissions, nutrient losses, and other
negative effects of biomass harvest and logistics. Since transport contributes a much larger fraction
of the overall greenhouse gas effects of lignocellulosic biomass than it does for grains and oilseeds,
more efficient harvest, densification, and delivery systems are clearly required.
With increased understanding of how different biomass characteristics perform during
downstream conversion processes, one can also expect optimization of biomass quality/performance
relationships. It will be important to track the intrinsic qualities of biomass that result from
special crop varieties or production practices as well as postharvest exposure to moisture, heat, or
biodegradation. Tracking these characteristics and exposures will also require source identification
and chain-of-custody documentation as well as new biomass quality measurement tools. This
optimization will also drive research and innovation to develop integrated supply-chain strategies
that improve product quality and performance at an affordable cost.
