ASABE Technical Library - Abstract

Abstract. The expansion of the renewable fuels industry in the US requires advances on a number of focus areas to ensure a reliable production and feedstock delivery system. The US DOE published a strategic analysis that estimates if the US agriculture and forest resources have the capability to produce at least one billion dry tons of biomass annually, in a sustainable manner. The Billion Ton Study (BT2) provides a means to predict the development of the biofuels industry. The estimates of potential biomass were obtained through the Policy Analysis System (POLYSYS) agricultural modeling framework and, were based on numerous assumptions about current and future inventory, production capacity, availability, and technology. The objective of this study is to assess the underlying assumptions for the range of conditions across a nation and determine their influence on total biomass predicted. Particularly, we look at the following assumptions: the production of perennial grasses is limited to rain-fed lands classified as cropland, cropland pasture and permanent pasture, and all conversion from pastureland to perennial grasses is limited to counties east of the 100th Meridian. The biomass predictions for the states bisected by the 100th Meridian were questioned based on the knowledge of local conditions. In collaboration with the Oak Ridge National Laboratory, we have carried out additional simulations in the POLYSYS framework, using the annual average precipitation data as a bound for land conversion to perennial grasses. We concluded that the potential perennial grass production in the US, and particularly in Texas, was overestimated by allowing cropland in regions with less than 635 mm (25 in.) precipitation to be converted into perennial grasses. The perennial grass production was reduced in the US and Texas by 7.7 % and 86.8%, respectively under the farmgate price of $60 per dry ton scenario.