Biomass Feedstock Storage for Quantity and Quality Preservation

Biomass feedstock must be stored between the time of harvest and its conversion to bioenergy products such as ethanol to ensure year-round, continuous supply of quality feedstock to conversion plants. Storage of biomass entails conserving both its dry matter content and its carbohydrate content which may be converted to ethanol. Moreover, it also entails preparing the biomass in terms of its composition, particle size, and pH for the pretreatment stage where cellulose is hydrolyzed into C6 sugars and later fermented into alcohol. The goal of this chapter is to provide an overview of these aspects related to biomass feedstock storage. Various storage options, ranging from open storage without any protection to highly sophisticated controlled environment, are first reviewed to highlight their advantages and limitations. The feedstock properties important from a storage perspective are then discussed. Potential alternatives to reduce dry matter losses during storage are discussed. Mathematical relationships correlating dry matter loss with its various causes are reported. These include drying, compaction, sealing, and freezing. The factors affecting the reduction in biomass recalcitrance are then presented, and their impact on quality parameters relevant to processing is discussed. The reduction of dry matter recalcitrance to prepare biomass for further processing is discussed with the options of incorporating those in storage facilities. Guidelines to select a storage method that may be used by design engineers or managers are also presented. The review showed that the importance of storage in the value chain is being realized, leading to greater interest on developing alternatives to improve storage efficiency.