CELLULOSIC ETHANOL PRO & CON

FOR:
- In Louisiana: Bagasse is ethanol from cellulosic sugar products.
- In Pennsylvania: Corn-based cellulosic ethanol.
- In Massachusetts: Pure research into the microbial breakdown of cellulosic biomass for ethanol (funded by Silicon Valley venture capitalist Vinod Khosla).

ADAMANTLY OPPOSED: John R. Benemann, Don C. Augenstein, Don J. Wilhelm and Dale R. Simbeck of the Institute for Environmental Management, Inc. (Palo Alto) at The Oil Drum:
- An independent analysis identified many problems with the currently proposed processes, including the relatively high costs of biomass delivered to commercial-scale plants (which would need to be 200 million liters per year output, or greater, for economics of scale), the problems with pretreatment, the low rates and yields of sugars from enzymatic cellulose hydrolysis, the resulting low sugar and ethanol concentrations, and the overall high energy consumption of the overall process. In addition to not tolerating high ethanol concentrations, genetically engineered organisms developed for combined hexose-pentose fermentations are subject to contamination, which will require prohibitively expensive containment systems.

- Even ignoring, as most studies do, such major problems, and using available corn stover and enzymatic hydrolysis, the currently favored biomass resource and process, our techno-economic analysis estimated a cost of ethanol twice as high as that of ethanol from corn. Forest residues and wastes, biomass crops, and municipal wastes are even less promising. The conclusions of this assessment are that none of the existing processes are ready for commercial applications in any foreseeable time frame and that continuing fundamental and applied R&D is required. Some opportunities may exist for near-term applications of cellulose conversion technologies to some specific, modest-scale, agricultural wastes.