The biorefinery feedstock supply system encompasses all the unit operations necessary to move biomass feedstocks from the land to the biorefinery (29). An overview of the feedstock supply system is depicted in Figure 2.3. Biomass production is the beginning of the feedstock

supply chain. It involves producing biomass feedstocks to the point of harvest. Production addresses important factors such as selection of feedstock type, land use issues, policy issues, and agronomic practices that drive biomass yield rates and directly affect harvest and collection operations.

Harvesting and collection encompasses all operations associated with getting the biomass from its source to the storage or queuing location. In addition to obvious operations such as cutting (or combining, swathing, or logging) and hauling, this often includes some form of densification such as baling, bundling, or chipping to facilitate handling and storage. Storage and queuing are essential operations in the feedstock supply system. They are used to deal with seasonal harvest times, variable yields, and delivery schedules. The objective of a storage system is to provide the lowest-cost method (including cost incurred from losses) of holding the biomass material in a stable, unaltered form (i. e., neither quality improvements nor reductions) until it is called for by the biorefinery.

Prior to conversion, the feedstock must be preprocessed to physically transform it into the format required by the biorefinery. Preprocessing can be as simple as grinding and preparing the biomass for increased bulk density or improved conversion efficiency, or it can be as complex as improving feedstock quality through fractionation, tissue separation, and blending.

Transportation generally consists of moving the biomass from the storage location to the biorefinery via truck, rail, barge, or pipeline. The system used directly affects how the feedstock is handled and fed into the conversion process. Transporting and handling methods are driven by the format and bulk density of the material; this makes them highly dependent on each other and on all the other operations in the feedstock supply chain.