Biomass Feedstock Storage for Quantity and Quality Preservation - Engineering and Science of Biomass Feedstock Production and Provision - page 182

Fig. 7.9 Outdoor storage of square bales of Miscanthus in Pena, Illinois, 2 years after harvest. The
blue protective tarpaulin breaks down in extreme weather conditions. Photograph courtesy of the
Department of Agricultural and Biological Engineering of the University of Illinois
Outdoor storage of baled biomass (Fig. 7.9 ) is most common. Cundiff et al. [ 45 ]
showed that storing biomass in the field is the most cost-effective for the specific
case they analyzed. However, outdoor storage method makes it impossible to con-
trol biomass quality and losses, or dry the harvested material to reduce its weight
and transport cost. Moreover, baling poses health hazards due to the growth of mold
(Fig. 7.10 ) and self-ignition risks [ 44 ] due to self-heating, which is a function of
moisture content in bales [ 20 ]. Open storage may be acceptable in arid or dry
regions but may be problematic in regions with frequent precipitation events.
Indoor or temperature-controlled storage provides better biomass quality con-
trol. In a case study on cotton stalks and almond tree prunings representing two
types of cellulosic biomass, Rentizelas et al. [ 44 ] compared three storage scenarios:
ambient storage, in a warehouse after drying, and covered without drying
(Table 7.4 ). The results showed that ambient storage caused twice the dry matter
loss as compared to covered storage, and that losses were negligible in dried ware-
housed biomass. However, the investment cost of a biomass warehouse is ten
times that of ambient storage, and the gain is 1 % of dry matter preserved per
month. Rentizelas et al. [ 44 ] demonstrated that using multiple biomass streams
allows maximizing the use of a storage facility and staggering harvest dates. This
increases the cost-eficiency of a drying and storage facility.
Mooney et al. [ 46 ] compared the storage options of baled switchgrass using dif-
ferent combinations of baling technology, covering, and storage methods. They
observed that bale shape (round or square) and cover type impacted the dry matter