Cellulosic ethanol production in the United States: Conversion technologies, current production status, economics, and emerging developments

Details of existing conversion technologies for cellulosic ethanol production, both hydrolysis and thermochemical, have been discussed along with their present adoption status. Furthermore, economics of ethanol production by using different conversion technologies has been discussed. Emerging conversion technologies and other developments which might affect the cellulosic ethanol production are also characterized. Based on current estimates, it was found that about 400 million gallons of cellulosic ethanol will be produced in the country in coming years using different conversion technologies. It was noticed that out of several available conversion technologies, thermochemical-based technologies are gaining popularity and it is projected that the use of these conversion technologies will reduce the cellulosic ethanol production cost significantly. Similarly, recent advancements in hydrolysis-based technologies have also helped in reducing the production cost of cellulosic ethanol. However, more resources will be needed in coming years to meet the policy goal of producing 21 billion gallons of cellulosic ethanol by the year 2022. It is expected that this review will be helpful in efficient allocation of resources for facilitating future technology development and in streamlining the whole initiative of cellulosic ethanol production in the United States. (C) 2009 International Energy Initiative. Published by Elsevier Inc. All rights reserved.