Comprehensive Analysis of External Dependency in Terms of Material Criticality by Employing Total Material Requirement: Sulfuric Acid Production in Japan as a Case Study

Securing stable material supply is of paramount importance since materials are fundamental to the economy and human well-being. The domestic production to consumption ratio has conventionally been utilized as a main index for external dependency in terms of material supply security and its criticality. However, the conventional approach confines its application to raw materials, which potentially risks reaching short-sighted conclusions in the policy-making process. Beyond the conventional analysis of external dependency, the development of a more applicable approach for every material is of paramount importance to consider the diversification of external dependency more comprehensively and to aid the analysis of overall material criticality. As such, this paper establishes a new methodology for analyzing external dependency related to every material and product by using the concept of total material requirement (TMR). Applying the methodology, the external dependency of sulfuric acid production in Japan is evaluated as a case study. Previously unexamined elements associated with external dependency in the conventional approach are revealed by this new comprehensive approach. The new approach may be of use to policymakers in designing more sophisticated and well-grounded material securement policy.