Rethinking environmental benefit allocation in industrial symbiosis

Industrial Symbiosis (IS) enables enterprises that typically operate independently to collaborate through the exchange of energy, materials, services, and knowledge. This approach helps reduce reliance on virgin resources, minimize waste, and contribute to climate change mitigation, among other impacts. Recently, the potential of this approach has gained attention, as policymakers are integrating IS into ambitious targets, such as 2050 climate neutrality. Moreover, initially mainly driven by cost savings, now IS is valued for its environmental gains. This shift has sparked interest in quantifying the advantages to both the overall network and individual enterprises. However, a standardized method for assessing these benefits has yet to be established. Most of the current methodologies found in literature and guidelines take a reductionist approach, addressing the multifunctionality issue in IS by isolating one or a few enterprises at a time, thus fragmenting the complex system. This approach, which focuses on identifying 'who benefits' among the enterprises involved in IS, overlooks the complexity of the entire system. To address the tension between the need for a systemic perspective and the desire to quantify each enterprise's contribution and environmental gains, this study proposes a new redistribution approach. This approach ensures that each enterprise improves its score in line with the overall rate of improvement in the industrial symbiosis, compared to a scenario where no symbiotic practices are implemented. This approach is based on the idea that, regardless of the types of products and organizations involved, the environmental benefits of IS are emergent properties of the entire industrial symbiosis network, a composite system. That is why rather than focusing on inputs, this approach redistributes the overall benefits and impacts across the network, shifting the allocation process from the Life Cycle Inventory stage to the Life Cycle Impact Assessment stage.