An analysis of net energy production and feedstock availability for biobutanol and bioethanol

In this study, the potential of biobutanol was evaluated as an alternative to bioethanol which is currently the predominant liquid biofuel in the US. Life-cycle assessments (LCAs) suggest that the net energy generated during corn-to-biobutanol conversion is 6.53 MJ/L, which is greater than that of the corn-derived bioethanol (0.40 MJ/L). Additionally, replacing corn with lignocellulosic materials in bioethanol production can further increase the net energy to 15.90 MJ/L. Therefore, it was interesting to study the possibility of using domestically produced switchgrass, hybrid poplar, corn stover, and wheat straw as feedstocks to produce liquid biofuels in the US. By sustainable harvest based on current yields, these materials can be converted to 8.27 billion gallons of biobutanol replacing 7.55 billion gallons of gasoline annually. To further expand the scale, significant crop yield increases and appropriate land use changes are considered two major requirements.