Logistic Constraints in Developing Dedicated Large-Scale Bioenergy Systems in the Southeastern United States

Multiple biomass-for-energy feedstock resources have been proposed and many or all of these may ultimately be needed. This paper focuses on perennial lignocellulosic feedstocks. In the United States, Perlack and colleagues estimated that by 2050 1.3 billion Mg of biomass could be sustainably harvested annually. However, over half of the herbaceous biomass in their estimate was derived from crop residues, a source that presents numerous concerns. Availability of land resources and the economic prospects for diverting land from food to energy production is further clouded by unknown variables such as the impact of increased human populations and higher living standards. Much effort is currently being given to corn and other starch or grain crops that can be readily converted to ethanol. Although these crops have served to jumpstart the fuel ethanol industry, they have much less potential to meet the growing demand, much greater potential for negative environmental impacts, and their use feeds the "food versus fuel" debate. The 2007 Energy Bill mandated annual production of 136 billion L of fuel (ethanol, etc.) from renewable feedstocks by 2022, a goal that will greatly impact U. S. agriculture. From 2009, all increases in renewable fuel production are to come from nonstarch sources, yet production of "cellulosic ethanol" is currently limited by the conversion technologies. In addition to conversion constraints, all bioenergy technologies will require equipment systems that can cost effectively collect, store, and deliver bulky distributed biomass to the bioenergy plant. These systems will emulate commercial systems that move herbaceous crops (e. g., cotton and sugarcane) to processing plants; however they must be fine tuned to address the requirements of the crop and the constraints of the land base. Important interactions occur between each component of the supply chain-agronomy, logistics, and processing-that are best not studied in isolation. Significant social issues also stand to influence landowner decisions regarding market entry and these will affect the function and profitability of a bioenergy plant. The business plan must provide a "win-win" for both the feedstock supplier and the plant owner. Other large questions about the development of bioenergy resources reside outside the system, e. g., bioenergy systems may be more cost competitive if the policy allows them to benefit from the potential ecosystem services they provide such as sequestering carbon.