Energy balance and global warming potential of corn straw-based bioethanol in China from a life cycle perspective

Abstract

<p>As the second largest corn producer in this world, China has abundant corn straw resources. The study assessed the energy balance and global warming potential of corn straw-based bioethanol production and utilization in China from a life cycle perspective. The results revealed that bioethanol used as gasoline and diesel blend fuel could reduce global warming potential by 10%–97% and 4%–96%, respectively, as compared to gasoline and diesel for transport. The total global warming potential, net global warming potential, net energy, and Net Energy Ratio per MJ ethanol generated from corn straw-based bioethanol system are estimated to be 0.20 kg CO₂-eq, 0.012 kg CO₂-eq, 0.60 MJ, and 1.87, respectively. By using sensitivity analysis, we found that the collected coefficient and compressing density of straw have a more obvious influence on energy balance; transportation distance has a more obvious influence on global warming potential emission factor. The by-products may be utilized as fertilizer, animal feed, cement replacement, or high-value lignin chemicals, which make a contribution to offsetting 0.28 MJ per MJ ethanol of energy consumption.</p