Energy gap method (EGM) to increase energy efficiency in industrial processes: Successful cases in polymer processing

A novel strategic decision methodology to increase energy efficiency in industrial processes, the Energy Gap Method (EGM), is presented. For this methodology, six different specific energy consumption levels are proposed; four of them are based on historical plant data and measurements in production processes, and the other two levels are based on benchmark references and thermodynamic minimum estimations. Five gaps or differences between specific energy consumptions can be calculated: production, quality, process, technological, and R&D gaps. Actions aiming at the reduction of the largest gaps are prioritized, taking into account the required resources and payback analyses. Four successful industrial case studies applying EGM in polymer processing are presented. In the first study, a blow molding process was diagnosed and the interventions obtained a specific energy consumption (SEC) reduction of 14%. For the second study, the same process used in the first study was employed to intervene in a second machine, obtaining an SEC reduction of 65%. For the third and fourth studies, an automotive part injection molding process was diagnosed and improved, obtaining SEC savings of 16% for the part production and around 7% for the whole production plant. EGM is not limited to polymer processing plants, and it could be adapted to other mass production processes.