Klein E. Ileleji, Shahab Sokhansanj, and John S. Cundiff

Abstract

This chapter presents the logistics of delivering cellulosic biomass feedstock from the farm gate to the plant gate. Unlike the more familiar starchy feedstock and oilseed such as corn and soybean, which can be cost-effectively delivered to the plant gate for processing at the commercial scale, cellulosic biomass presents unique handling challenges at the commercial scale, which make them expensive to utilize. In the Introduction section of this chapter we discuss the essential components of the logistics chain and the unique logistical needs of lignocellulosic biomass as compared with starchy grain feedstocks. Then we discuss on-farm logistics of biomass harvest and delivery, which include biomass availability and distribution, harvest and collection, preprocessing operations, transport, economic, energy inputs, and carbon emissions. After that we discuss the logistics of handling feedstock at the plant gate, we examine the operations used in grain elevators, and we discuss the envisaged parallel operations that would occur in a biorefinery processing lignocellulosic biomass. Next we discuss related agricultural logistics operations (cotton harvest logistics, sugarcane harvest logistics, and fuel chip harvest logistics) and their application to biomass. A comparison of herbaceous fiber and grain logistics chain is also presented. The last section briefly presents a systems approach to feedstock logistics, discussing some unique opportunities to save cost and energy by integrating unit operations throughout the logistics chain.

Introduction

Lignocellulosic feedstocks from plant biomass such as grain plant residues (corn stover, wheat straw, rice straw, etc.), energy crops (switchgrass, canary reed grass, miscanthus, etc.), and wood (residues, wood chips, hybrid poplars and willows, etc.) are currently being inves­tigated for use in the production of second- generation advanced fuels (cellulose ethanol, FT-diesel, etc.) and for biopower either fired alone or co-fired with coal. As compared to

Biofuels from Agricultural Wastes and Byproducts Edited by Hans P. Blaschek, Thaddeus C. Ezeji and Ju rgen Scheffran 117 © 2010 Blackwell Publishing. ISBN: 978-0-813-80252-7

corn-grain-for-ethanol, their utilization for energy production does not compete with the demand for agricultural feedstocks such as grain for food and feed production. The increased production of corn ethanol in the United States has raised a number of concerns in recent times, the major one being the moral and social consciousness of using a food crop for fuel that could potentially drive up world food prices and create a hunger crisis in poor regions of the world. Another obvious reason for the use of lignocellulosics is because it would be practically impossible to produce the mandated fuel ethanol volumes with grain crops alone, even if the entire grain crop produced in the United States were converted to ethanol. Additionally, the Energy Independence and Security Act of2007 (WhiteHouse News Releases 2007) sets a mandatory Renewable Fuels Standard (RFS) for the production of 36 billion gallons of fuel ethanol by 2022, of which 15 billion must be produced from cellulose. While there is no commercial scale cellulose ethanol plant, there are commercial power plants in North America, Europe, and Asia that have some experience using biomass on a large scale.

Commercial scale utilization of lignocellulosic biomass is not a trivial task and is quite different from the use of grain. The logistics and handling cost of feedstock can be very expensive and is one of the major reasons for the high cost of producing liquid fuels and power from lignocellulosic feedstocks. In corn stover to ethanol production, feedstock and handling cost together can make up as much as 36% of the production cost (Ruth et al. 2002). The three diverse types of biomass mentioned previously, while chemically the same, are quite different in their times of harvest/collection, method, and physical characteristics. This means that the unique differences of these feedstocks need to be considered when designing an effective biomass logistics system. Once the feedstock is ready for harvest and collection, field machinery must be scheduled for harvesting the feedstock within a narrow window of opportunity usually from a few weeks to 3 months. Harvest is followed by transportation to on-farm storage, preprocessing, or biorefinery plants. Sustainable supply of feedstock from on farm storage must be delivered to the biorefinery year round to meet about 350 days of production schedule while maintaining an average of at least 10 days inventory at the biore­finery. The logistics of all these operations must be coordinated with the goal of delivering the least cost feedstock of the specified quality at the plant gate.

The design and operation of efficient feedstock delivery systems are vital to reducing the cost of feedstock/handling for commercial bioenergy production from lignocellulosics. Feedstock handling involves field harvest and collection, storage, preprocessing, transporta­tion and handling/delivery at the biorefinery. In the next two sections, we will discuss these operations in two segments: (1) field harvest/collection, preprocessing, and transport to the biorefinery and (2) handling/delivery of inbound feedstocks at the biorefinery. The third section will present the principles required for an efficient logistic system for biomass, illus­trated by several commercial operations making use of existing systems in U. S. agriculture. Finally, a systems integration approach will be presented as a way of approaching feedstock delivery by integrating it within the production system of the bioenergy conversion process.