In this study, energy analysis was conducted for the production of biodiesel in a spiral reactor using supercritical tert-butyl methyl ether (MTBE). This study aims to determine the net energy ratio (NER) and energy efficiency for the production of biodiesel using supercritical MTBE and to verify the effectiveness of the spiral reactor in terms of heat recovery efficiency. The analysis results revealed that the NER for this process was 0.92. Meanwhile, the energy efficiency was 0.98, indicating that the production of biodiesel in a spiral reactor using supercritical MTBE is an energy-efficient process. By comparing the energy supply required for biodiesel production between spiral and conventional reactors, the spiral reactor was more efficient than the conventional reactor. (C) 2015 Elsevier Ltd. All rights reserved.