The effect of environmental and social value objectives on optimal design in industrial energy symbiosis: A multi-objective approach

Industrial symbiosis can play a prominent role in greening existing industrial networks by reducing the costs of raw material and energy exchanges, as well as decreasing the environmental impact of businesses. Energy symbiosis, a key component of industrial symbiosis, could reduce the need for fossil fuels and contribute to the circular economy by recovering waste energy throughout production processes. There are currently gaps in the literature regarding the social aspects of industrial symbiosis, including in the selection of energy partners. This paper presents a novel mixed-integer linear programming (MILP) model incorporating the key sustainability pillars in the optimal design of an energy symbiosis network, which also accounts for the fluctuation of energy demand in different seasons. It also shows, using a case study, that the model applies to a real-life situation and could be a useful decision-making tool to firms interested in promoting energy symbiosis. The results show that the economic and environmental objectives promote a similar energy exchange network. Social value preference, however, could encourage more symbiotic connections, which, as the results suggest, does not decrease the economic and environmental effect of the symbiotic network. The research provides a new perspective on the role of social objectives individually or combined with other sustainability pillars in designing optimal energy symbiosis networks.