Any purchaser of biomass is interested in the cost of the material as it enters their plant. The plant can be burning the biomass directly to produce heat and power, or it can be using the biomass as a feedstock for some more complex conversion process to produce a high-value product. In this chapter, the term “feedstock” is used to refer to any raw biomass before its chemical structure is modified by a conversion process, be it direct combustion, thermochemical, or biological.

Feedstock cost ($/dry ton) is defined as the cost of the stream of size-reduced material entering the reactor at the bioenergy plant for 24/7 operation. (The reactor is defined as the unit operation where an initial chemical change in the feedstock occurs.) The reason for choosing this end point for the biomass logistics system is twofold:

1. The plants that can operate continuously, 24/7, have an advantage. Maximum production (tons/yr) per unit of capital investment gives a competitive advantage in the market place — the cost to produce the product is lower.

2. Some logistics systems do size reduction with the harvesting machine, while some reduce size at a transfer point between in-field hauling machines and highway hauling machines (perhaps as a prerequisite to a densification step), and some reduce size at the entrance to the processing plant. In order to compare the several systems, it is necessary to have a consistent end point for the system analysis.

The reader should be aware that many studies in the literature select a different analysis end point than used here. A typical end point is the cost of feedstock when a truckload of raw biomass enters the plant gate. This end point is favored because of tradition. Some agricultural (and forest product) industries still pay the producer when the raw material is delivered to their plant. Other industries have moved away from this model.