*3.2. Energy E*ffi*ciency*

**Process unit** The ratio of energy outputs to inputs in the process is defined as energy efficiency [32]. The energy outputs involve the energy available in biodiesel, bioethanol, and glycerol as well as produced heat. The energy inputs comprise the energy available in raw materials as well as steam, electricity, and fuel.

The energy consumptions of the scenarios are presented in Figure 6. The lower heating values are used to calculate the energy content of raw materials and products. The energy efficiency of scenarios 1 and 2 are 64.8% and 64.1%, respectively. In scenario 2, the energy consumption of the biodiesel production unit is more than that in scenario 1. On the other hand, the energy content of biodiesel is higher than that of ethanol, and in scenario 1, the amount of produced biodiesel is considerably higher than scenario 2. Thus, for the production of a higher amount of energy, transesterification with ethanol is preferred.
