Diversity and Ubiquity: the antecedents of resilience of industrial symbiosis networks

Industrial symbiosis networks (ISNs) have been recognized as extremely vulnerable to perturbations such as changes in production volumes of the involved firms or in costs for waste disposal and input purchasing. These... [ view full abstract ]

Industrial symbiosis networks (ISNs) have been recognized as extremely vulnerable to perturbations such as changes in production volumes of the involved firms or in costs for waste disposal and input purchasing. These perturbations are able to affect the feasibility conditions of industrial symbiosis (IS) relationships, which negatively affect the amount of economic advantages that firms gain from IS. Since the economic benefit is the main driver pushing firms to form and maintain symbiotic relationships, any reduction of the economic advantages stemming from the IS may be enough to motivate firms to interrupt the symbiotic flows or, in the worst case, to leave the ISN (Mirata, 2004). This might also cause the disruption of the ISN as a result of a domino effect due to the interconnectedness among the firms in the ISN (Zeng et al., 2013). To avoid this critical problem, ISNs should be designed to be resilient. Resilience is related to “the capacity of a system to absorb disturbance and reorganize while undergoing change so as to still retain essentially the same function, structure, identity, and feedbacks” (Walker et al., 2004). A recent review by Meerow and Newell (2015) confirms that resilience has not been a research focus of industrial ecology and more in depth of IS. The literature provided some preliminary contributions about resilience of ISNs, analyzing it in terms of network vulnerability and measuring it by using network theory metrics (Chopra and Khanna, 2014; Li and Xiao, 2017; Li and Shi, 2015; Zeng et al., 2013; Zhu and Ruth, 2013). Despite the usefulness of these contributions, a theoretical understanding of the antecedents of resilience is currently lacking. This paper is aimed to fill this gap. We frame ISNs as the analogous of ecological systems, i.e., as industrial ecosystems made by firms performing specific functions (waste exchanges) (Liwarska-Bizukojc et al., 2009); in doing so, the ISN generates two main services: i) to create economic benefits for firms (organisms); and ii) to create environmental benefits for the collectivity as a whole (external environment). Through a review of the ecological literature, we identified the two antecedents of ecosystems’ resilience: ecosystem’s diversity and organisms’ redundancy. We frame these properties in the IS field, defining the following indices: i) diversity of the ISN; ii) diversity of firm in the role of waste producer; iii) diversity of firm in the role of waste user; iv) ubiquity of waste produced; v) ubiquity of waste used. Basing on these indices, we design a resilience index at the firm level, assessing the extent to which the removal of that firm from the ISN is critical for the ISN’s resilience. We use some case studies to test the application of the proposed index to real analysis. The application of resilience index provides useful indications about how to make ISNs more resilient to perturbations.