Sustainable life cycle and energy management of discrete manufacturing plants in the industry 4.0 framework

Industry 4.0 (I4.0), through the digitalization and interconnection of manufacturing processes, can offer opportunities to improve production systems' sustainability. Despite the increasing number of scientific review papers related to I4.0 and production sustainability, most approaches and tools for sustainability evaluation lack of a tangible implementation framework. The paper presents a framework that originated from the plant metabolism concept, a simplified version of industrial metabolism. It is based on Energy Material Flow Analysis (EMFA) and Life Cycle Assessment (LCA) tools for production plants' economic and sustainability assessment, using the I4.0 enabling technologies. A Multi-Criteria Decision Making (MCDM) method combines the two sustainability pillars for aiding companies in optimizing their production processes towards a reduction of energy/material flows. The combination of EMFA, LCA and MCDM tools into a plant metabolism-based model is the main novelty of this paper. The framework consists of three main phases. The first phase allows to model the manufacturing system by defining the plant layout, the assets, and the input/output flows. The second phase allows gathering information from the manufacturing plant to assess environmental and economic Key Performance Indicators (KPIs) following the LCA principles. The third phase consists of post-processing results, minimizing specific KPIs for establishing the optimal production scenario. A washing machine plant has been chosen as a case study to demonstrate the proposed method's capability in authentic contexts. Besides, the effectiveness in supporting companies in the analysis, identifying criticalities, and the proper energy and material flows management of production plants has been verified. Plant managers could use this framework for managing the production plans. From the scientific standpoint, the proposed method positively contributes to integrating the existing state of the art studies concerning the I4.0-related framework for the sustainability assessment and energy/material flows minimization of production systems.