Net Energy Analysis of Molasses Based Bioethanol Production in Indonesia

Abstract

Molasses is mostly used as feedstock for the bioethanol production in Indonesia. Bioethanol industries has the potential to be more developed if the mandate of blending gasoline with 5% bioethanol is implemented. However, some previous studies abroad have shown that mostly the net energy for producing bioethanol is negative. The main purpose of this research is to analyze the net energy requirement if a bioethanol conversion plant from scenario of a bioethanol producer in East Java. Bioethanol conversion processes inside the plant are pre-fermentation, fermentation, evaporation, distillation and dehydration. Method which was used in this research are modelling and calculation made on monthly basis for plant capacity of 30,000 KL/ year ethanol of 99.5% purity. The result shows that the total energy required to produce 1 L of ethanol is 4.55 MJ. The energy content of 1 L ethanol is 23.46 MJ. The largest energy requirement is for evaporation process (62%) followed by distillation process (33%). Thus, the net energy requirement for bioethanol production process is positive.