M3-IS-LCA: A Methodology for Multi-level Life Cycle Environmental Performance Evaluation of Industrial Symbiosis Networks

Abstract In industrial symbiosis networks (ISNs), there are multiple stakeholders involved that require different levels of environmental performance insight for specific organizational goals. Life cycle assessment (LCA) has been widely applied to holistically evaluate the environmental benefits of ISNs and identify burden shifts. Representing ISNs in LCAs is complex due to resource flows with multiple sources and sinks and inter-company waste-to-resource exchanges. Furthermore, existing LCA methodologies face challenges in using one model for multi-level analysis to provide the network, entity, and resource flow-level perspectives of LCA results. To address these challenges, this study introduces M3-IS-LCA, a methodology for multi-level matrix-based modeling and analysis of the life cycle environmental impacts of ISNs. A formalism is outlined for constructing the model and analyzing the model so that LCA results can be provided at the levels of the network, individual company, and specific resource flows. M3-IS-LCA is tested through an LCA case study that evaluates a potential food waste valorization ISN in Singapore. The case study demonstrated that the methodology can analyze the environmental performance of an entire ISN. Through manipulation of the demand vector in the model, the network-level results can be disaggregated to the levels of individual companies and resource flows. In flow-level analysis, M3-IS-LCA can isolate the environmental impacts of recycling processes to determine their contribution to the environmental impacts of specific companies or the network. M3-IS-LCA can be applied to industrial symbiosis collaboration platforms to evaluate the environmental performance of existing or prospective waste-to-resource exchanges.