Realizing CO2 emission reduction through industrial symbiosis: A cement production case study for Kawasaki

This article is one effort to examine the present and potential performances of CO2 emission reduction though industrial symbiosis by employing a case study approach and life cycle CO2 analysis for alternative industrial symbiosis scenarios. As one of the first and the best-known eco-town projects, Kawasaki Eco-town was chosen as a case study area. First, the current industrial symbiosis practices in this area are introduced. To evaluate the potential of reducing the total CO2 emission through industrial symbiosis, alternative industrial symbiosis scenarios are then designed based on a questionnaire survey of 57 major local industries, to which 35 companies appropriately responded. The main focus of this paper is to calculate the total CO2 emission for different scenarios by adopting a life cycle CO2 analysis method. We then present recommendations on further improvement with consideration of the local realities. Our findings are that industrial symbiosis practices in Kawasaki Eco-town still have room for improvement in that greenhouse gas emissions can be further reduced and natural resources conserved through effective material exchanges, not only between companies, but also with the surrounding area. To encourage material exchanges between the municipality and industry, the city government should introduce a detailed separation program for garbage collection so that wastes can be effectively reused. In addition, the Waste Disposal and Public Cleaning Law needs amending so that industries can effectively use municipal solid waste in their manufacturing.