Life Cycle Assessment of Bioethanol Produced from Banana Peduncle

Abstract Biofuel production has been promoted in part to reduce dependency on fossil fuels in transportation due to fewer environmental emissions. Feedstocks for biofuels include agricultural waste and non-edible crops, suggesting that large amounts of waste can be used to produce biofuels such as bioethanol, which is currently being blended with gasoline in the Philippines as transportation fuel. However, shifting from non-renewable fuels to bioethanol and other biofuels as the dominant transportation fuel must consider aspects other than fuel usage. The objectives of this study are to perform cradle-to-grave life cycle analysis on bioethanol produced from banana peduncle and determine the contributions of each stage in the life cycle to different environmental impacts and compare the results with those of other transport fuels. The contributions of each stage in the life cycle of bioethanol are modelled in openLCA software with the ReCiPe impact assessment method. It was identified that electricity use in simultaneous saccharification and fermentation, and sulfuric acid consumption are the main contributors to the different environmental impacts. Comparison of the results of banana peduncle bioethanol production stage to those of the first-generation bioethanol production showed that most of the emissions were lower except for those pertaining to freshwater ecotoxicity, human toxicity, marine ecotoxicity, and metal depletion. Comparing fuel use, environmental impacts of conventional gasoline were slightly lower than those of a 10% mix with bioethanol. But impacts of the 85% mix with bioethanol in climate change and marine eutrophication are higher by 29% and 37%, respectively, than those of conventional gasoline. Overall, increasing the ethanol concentration would reduce the emissions during fuel usage but impacts of production will increase. Potential process improvements for environmental performance of bioethanol from banana peduncle are in the pre-treatment methods and fermentation set-up in bioethanol production, use of renewable power, and ethanol blending concentrations with gasoline.