Study identifies gaps in second-generation biofuels

By Timothy Charles Holmseth | July 08, 2008
Web exclusive posted August 1, 2008 at 11:16 a.m. CST

A U.S. DOE international study conducted to identify research gaps in transportation fuels has been published by the International Energy Agency. "Gaps in the Research of Second-Generation Transportation Biofuels" was initiated by Larry Russo of the DOE's Office of Biomass Program and led by Michael Ladisch of Purdue University.

International participants in the project - internally called Task 41, Project 2 - were the United States, Finland, the Netherlands, Sweden, United Kingdom, and the European Commission.

"Given the wide range of efforts that will hopefully continue to expand, it might appear that research gaps would be difficult to identify. However, on the contrary, this project team found a number of very important gaps," the report said.

"In the long-term, it is essential to promote the economic feasibility of second-generation biofuels," it said. "This publication has identified gaps within these areas which must be addressed to more quickly move the product from the laboratory to the billion gallon scale that represents the daily international consumption of liquid transportation fuels currently derived from petroleum."

Research gaps identified were found in bio-processing and thermo chemical conversion. "The bioprocessing of cellulosic material has significant potential, but key impediments exist for the economical attractive implementation of procession technology that would convert a solid cellulosic feedstock into a liquid fuel," according to the report.

One specific gap identified was cellulose pretreatment and the cost of enzymes, fermentation of a range of substrates to ethanol, and reduction of capital, as well as operating expenses. "While a number of research initiatives are examining the effect of hydrolysis on cell-wall structure, research on pretreatment that economically modifies this structure to improve downstream processing is needed," the report said.

Research gaps were also found in thermal processing and exist in the post-reaction processing of gases or oil from gasification and pyrolysis systems respectively. "The feedstocks created by the process is a first step and could lead to a catalytic conversion process that generates liquid transportation fuels," the report said. A recent paper published by McKeough and Kurkela in 2007 indicates that this type of liquid fuel could be produced for approximately $2.65 per gallon.

The 20-page report utilized and cited nearly 100 external resources and references. It assesses the possibilities of bioethanol, biomethane, methanol, dimethyl, biodiesel, green pyrolysis diesel, P-series fuels, synthetic diesel, and hybrid fuels.

The report can be viewed in its entirety at