Modeling of energy efficiency indicator for semiconductor industry

For purposes of energy conservation and environmental protection, the government of Taiwan has set long-term, solid policies to continuously encourage and assist the industry in improving the efficiency of energy utilization. While practical energy saving has been successful to a limited extent due to multiple actions, no strong evidence of improvement in energy efficiency was observed from the energy efficiency indicators (EEI) system, according to annual national energy statistics and survey. In order to answer the question what the role energy efficiency plays in the EEI system, a structural analysis of EEI is absolutely inevitable. The model is developed on the premise that the design parameters of the process are used to compare against the operational parameters for energy differences. Utilization index of production capability and variation index of energy utilization are formulated as two variables in the model to describe the differences between EEIs. An industrial example that produces eight-inch silicon wafer in the semiconductor industry of Taiwan was selected to demonstrate the application of the model. The annual energy utilization efficiency of the process was evaluated and the amount of energy that had been saved or overused in the process was computed as well.