Productivity and energy efficiency assessment of existing industrial gases facilities via data envelopment analysis and the Malmquist index

The current trend towards improving energy efficiency in industry calls for advanced decision-support tools for quantifying the level of efficiency of industrial facilities. This work applies Data Envelopment Analysis (DEA) to assess the performance of a set of 34 Air Separation Units (ASUs) producing industrial gases via air distillation. We identify the best ASUs according to energy efficiency and productivity criteria and define improvement targets for the units found inefficient. Furthermore, we analyze the temporal evolution of the efficiency scores using the Malmquist Productivity Index (MPI), which is calculated from real data of a gas company operating ASUs around the world. Our results provide insight on how to improve the efficiency of existing plants by identifying sources of inefficiency and reference facilities that could be used for benchmarking.