Supply risk footprints per unit GHG reduction on low-carbon energy technologies

The life cycle of metal resources begins with mining and proceeds via material processing and product manufacture and use to possible recycling, reuse, remanufacturing, or final disposal. Today, this entire process is rarely... [ view full abstract ]

The life cycle of metal resources begins with mining and proceeds via material processing and product manufacture and use to possible recycling, reuse, remanufacturing, or final disposal. Today, this entire process is rarely completed within a single country, and metal resources move around the globe from the countries where mining takes place through supply chains connected by international trade. Substantial amounts of metal resources are also exported in the form of used products for reuse, recycling, and remanufacturing elsewhere. International trade is thus an inseparable part of the life-cycles of metals including “critical metals” that are essential for the economies of industrialized nations which must change into a low-carbon society.

The Nationally Determined Contributions (NDC) was agreed at the 21st Conference of the Parties (COP 21) held in Paris at the end of 2015. In efforts to achieve Japan’s NDC under the Paris Agreement, which includes a 26% reduction of 2013 greenhouse gas emissions by the year 2030, Japan has to promote development and expansion of low-carbon energy technologies. For certain critical metals, only few countries mine them, and some of these countries may not be economically or politically stable, often leading to instability of metals mining operations and thus a major supply risk to its downstream supply chain. Hence, there is a concern that Japan will be further exposed to supply risk of the critical metals with the reduction of GHG emission through the technological reliance.

Against this background, the study aims to carry out hybrid life cycle assessment (LCA) for comparing the supply risk footprints per unit GHG reduction among low-carbon energy technologies. The hybrid LCA assumes combines process analysis and multiregional input-output analysis (MRIO) and calculates mining risk footprints of the technologies (photovoltaic solar, hydropower, wind power, electric vehicles etc.) with the assumption that they are introduced in Japan. The CEDA integrated scenarios is used to compile the process data on the technologies, and a global-link input-output model (GLIO) is employed as MRIO to ensure a global system boundary and high sector resolution of Japanese commodities. Mining risk is quantified by using the market concentration of output of the metals and political risk of the countries where the metals are mined. The mining risk footprint implies direct and indirect the mining risk affecting a technology through its consumption of the metal. The metals considered in this study are neodymium, cobalt and platinum.