Background

The United States Department of Energy (DOE) has supported a research and development program for the establishment of renewable, biomass-derived, liquid fuels for the better part of the last twenty years. These “biofuels ” represent opportunities to respond to uncertainties about our energy security and the future health of our environment. Throughout its history, the Biofuels program has experienced an ongoing fiscal “roller coaster”. Funding has ebbed and flowed with changing political and public attitudes about energy1. The program was initiated in a flood of funding in the late 1970s related to the energy shortages experienced in that period. The flooding turned rapidly to drought as falling oil prices dissipated public concern about energy supplies. In the late 1980s, funding for the program slowly increased, driven by national security issues. Despite its turbulent fiscal history, the Biofuels Program has made tremendous technical progress. The centerpiece of the program is the development of what we refer to as “bioethanol”; ethanol produced from cellulose and hemicellulose contained in grasses, trees and waste biomass. The research and development carried out by DOE over the decade of the 1980s, for example, resulted in a three-fold reduction in the estimated cost of ethanol mad