Shigemi Kagawa

A Structural Decomposition of Energy Consumption Based on a Hybrid Rectangular Input-Output Framework: Japan's Case

This paper proposes an I-O SDA model, based on a commodity technology assumption, to identify the sources of changes in the energy demand structure, the non-energy input structure, the non-energy product-mix and the non-energy final demand of embodied energy requirements. The model contains two features. First, the hybrid rectangular input-output framework expressed in both monetary and physical terms is introduced to relax the effects of different energy prices among industrial sectors on the input structure in physical terms. Second, the demand structure of the input-output system is decomposed into the structure of energy sectors and other sectors by applying the hierarchy system with feedback loops of non-energy sectors. We identify the sources of the changes in Japans energy use structure between 1985 and 1990. The major findings are that the total energy requirement has increased, mainly because of the changes in the non-energy final demand, while the product-mix changes have opposite effects, that is, energy savings.

Industrial ecology and input-output economics: an introduction

Abstract Industrial ecology aims at closing material cycles within industrial systems by developing symbiotic functions among system components. How industrial systems are structured and how they transform, use and discard natural resources is, therefore, the key focus of industrial ecology. As an introduction to this issue of Economic Systems Research, which is themed around industrial ecology, the current paper aims to provide a background on industrial ecology, highlighting the role of and contributions from input–output economics. A brief history of industrial ecology and input–output economics is presented, focusing on a number of specific areas where the two disciplines overlap. The role of input–output economics in industrial ecology is discussed in terms of how input–output economics has been, and is being, utilized in industrial ecology. Finally the papers that are presented in this issue are briefly introduced.

Global flows of critical metals necessary for low-carbon technologies: The case of neodymium, cobalt, and platinum

This study, encompassing 231 countries and regions, quantifies the global transfer of three critical metals (neodymium, cobalt, and platinum) considered vital for low-carbon technologies by means of material flow analysis (MFA), using trade data (BACI) and the metal contents of trade commodities, resolving the optimization problem to ensure the material balance of the metals within each country and region. The study shows that in 2005 international trade led to global flows of 18.6 kt of neodymium, 154 kt of cobalt, and 402 t of platinum and identifies the main commodities and top 50 bilateral trade links embodying these metals. To explore the issue of consumption efficiency, the flows were characterized according to the technological level of each country or region and divided into three types: green (“efficient use”), yellow (“moderately efficient use”), and red (“inefficient use”). On this basis, the shares of green, yellow, and red flows in the aggregate global flow of Nd were found to be 1.2%, 98%, and 1.2%, respectively. For Co, the respective figures are 53%, 28%, and 19%, and for Pt 15%, 84%, and 0.87%. Furthermore, a simple indicator focusing on the composition of the three colored flows for each commodity was developed to identify trade commodities that should be prioritized for urgent technical improvement to reduce wasteful use of the metals. Based on the indicator, we discuss logical, strategic identification of the responsibilities and roles of the countries involved in the global flows.

Estimates of embodied global energy and air-emission intensities of Japanese products for building a Japanese input-output life cycle assessment database with a global system boundary.

To build a life cycle assessment (LCA) database of Japanese products embracing their global supply chains in a manner requiring lower time and labor burdens, this study estimates the intensity of embodied global environmental burden for commodities produced in Japan. The intensity of embodied global environmental burden is a measure of the environmental burden generated globally by unit production of the commodity and can be used as life cycle inventory data in LCA. The calculation employs an input–output LCA method with a global link input–output model that defines a global system boundary grounded in a simplified multiregional input–output framework. As results, the intensities of embodied global environmental burden for 406 Japanese commodities are determined in terms of energy consumption, greenhouse-gas emissions (carbon dioxide, methane, nitrous oxide, perfluorocarbons, hydrofluorocarbons, sulfur hexafluoride, and their summation), and air-pollutant emissions (nitrogen oxide and sulfur oxide). The uncertainties in the intensities of embodied global environmental burden attributable to the simplified structure of the global link input–output model are quantified using Monte Carlo simulation. In addition, by analyzing the structure of the embodied global greenhouse-gas intensities we characterize Japanese commodities in the context of LCA embracing global supply chains.

A Spatial Structural Decomposition Analysis of Chinese and Japanese Energy Demand: 1985–1990

This paper proposes a spatial structural decomposition analysis to measure the effects of the changes in intra- and inter-country linkages on the embodied energy demand in the concerned country. For the empirical analysis, we have used the China- Japan inter-country input–output tables for 1985 and 1990, expressed in constant prices of 1990. The empirical results reveal that (1) at least for the period between 1985 and 1990, the effects of the non-competitive input structural changes in China on the primary energy requirements of Japan were negligible, and (2) the contribution of the Japanese final demand shifts on the total change in Chinese primary energy demand was 40 times larger than that of the Chinese final demand shifts on the primary energy requirements of Japan. The Japanese policy makers should concentrate on the energy impacts of the changes in the domestic production structure rather than the changes in the Chinese production structure.

Improving The Completeness Of Product Carbon Footprints Using A Global Link Input-Output Model: The Case Of Japan

This paper is concerned with the main activities of Japans ‘Disclosure of CO2 emissions’ programme, aimed at illustrating the CO2 emissions associated with consumer products as a ‘carbon footprint’ (CF). Although the current, provisional guidelines for calculating product carbon footprints specify that only the bottom-up approach is to be used for this purpose, this paper presents useful applications of input–output analysis that can improve the reliability of the method considerably, by taking full advantage of the strengths of input–output analysis. To this end, we first estimated the global carbon footprint (GCF) of food and consumables in Japan, using a global link input–output (GLIO) model comprising 804 economic sectors in Japan and 230 foreign countries and regions. By visualizing the GCF on a world map, the global distribution (including Middle East and African countries) of the induced CO2 emissions of each of the Japanese sectors were identified. To investigate the scope for reducing the data collection burden for CF practitioners, GCFs were compared with CFs obtained using a single-region input–output model. This showed that there are certain commodity groups with a CF equating to 70% to over 90% of the corresponding GCF, even if the imported goods used for producing a Japanese domestic product are considered environmentally equivalent to their domestically produced counterparts. Furthermore, it was identified which data should preferably be collected by the bottom-up approach to secure CO2 emissions coverage greater than a certain predefined level and keep data and labour costs at a minimum.

MaTrace: Tracing the Fate of Materials over Time and Across Products in Open-Loop Recycling

Even for metals, open-loop recycling is more common than closed-loop recycling due, among other factors, to the degradation of quality in the end-of-life (EoL) phase. Open-loop recycling is subject to loss of functionality of original materials, dissipation in forms that are difficult to recover, and recovered metals might need dilution with primary metals to meet quality requirements. Sustainable management of metal resources calls for the minimization of these losses. Imperative to this is quantitative tracking of the fate of materials across different stages, products, and losses. A new input-output analysis (IO) based model of dynamic material flow analysis (MFA) is presented that can trace the fate of materials over time and across products in open-loop recycling taking explicit consideration of losses and the quality of scrap into account. Application to car steel recovered from EoL vehicles (ELV) showed that after 50 years around 80% of the steel is used in products, mostly buildings and civil engineering (infrastructure), with the rest mostly resided in unrecovered obsolete infrastructure and refinery losses. Sensitivity analysis was conducted to evaluate the effects of changes in product lifespan, and the quality of scrap.

Finding environmentally important industry clusters: Multiway cut approach using nonnegative matrix factorization

Abstract This paper proposes an optimal combinatorial method for finding groups of industries with relatively large CO 2 emissions through industrial relations. Using an economic input–output table, we estimated a non-symmetric matrix describing how much CO 2 is emitted in producing the commodity of industry i , which was purchased to produce commodity of industry j , to meet the final demand for a specific commodity. A symmetric strength of relations matrix describing the CO 2 emissions associated with the industrial relations was further estimated using the non-symmetric matrix. The strength of relations matrix can be viewed as a representation of the supply-chain network of the final commodity. In this study, we estimated the strength of relations matrix associated with the final demand for automobiles and applied the multiway cut approach using nonnegative matrix factorization to the matrix in order to find environmentally important industry clusters in the Japanese automobile supply chain. According to our empirical results, the optimal number of industry clusters is 19, and 4 industry clusters are playing a key role in CO 2 emission reduction.

A Simple Multi-Regional Input–Output Account for Waste Analysis

The present paper provides a simple multiregional input–output model for waste analysis with which to estimate intraregional and interregional effects of industrial wastes embodied in regional final consumptions. The empirical analyses using 1995 nine-regions input–output tables reveals the regional properties of the interregional linkage effects. The Kanto and Kinki regions remarkably control the industrial waste emissions and waste landfills within their own regions by importing waste-intensive intermediate goods and services from the other regions. The Chugoku and Shikoku regions greatly contributed to the production of the waste-intensive goods and services for the other regions, considering the waste emissions and waste landfills relative to the commodity production levels. We also find that the household consumption behaviour in other regions indirectly plays a more important role in waste emissions than the municipal waste disposal behaviour in the region in question at least in 1995.

Global Mining Risk Footprint of Critical Metals Necessary for Low- Carbon Technologies: The Case of Neodymium, Cobalt, and Platinum in Japan

Meeting the 2-degree global warming target requires wide adoption of low-carbon energy technologies. Many such technologies rely on the use of precious metals, however, increasing the dependence of national economies on these resources. Among such metals, those with supply security concerns are referred to as critical metals. Using the Policy Potential Index developed by the Fraser Institute, this study developed a new footprint indicator, the mining risk footprint (MRF), to quantify the mining risk directly and indirectly affecting a national economy through its consumption of critical metals. We formulated the MRF as a product of the material footprint (MF) of the consuming country and the mining risks of the countries where the materials are mined. A case study was conducted for the 2005 Japanese economy to determine the MF and MRF for three critical metals essential for emerging energy technologies: neodymium, cobalt and platinum. The results indicate that in 2005 the MFs generated by Japanese domestic final demand, that is, the consumption-based metal output of Japan, were 1.0 × 10(3) t for neodymium, 9.4 × 10(3) t for cobalt, and 2.1 × 10 t for platinum. Export demand contributes most to the MF, accounting for 3.0 × 10(3) t, 1.3 × 10(5) t, and 3.1 × 10 t, respectively. The MRFs of Japanese total final demand (domestic plus export) were calculated to be 1.7 × 10 points for neodymium, 4.5 × 10(-2) points for cobalt, and 5.6 points for platinum, implying that the Japanese economy is incurring a high mining risk through its use of neodymium. This countrys MRFs are all dominated by export demand. The paper concludes by discussing the policy implications and future research directions for measuring the MFs and MRFs of critical metals. For countries poorly endowed with mineral resources, adopting low-carbon energy technologies may imply a shifting of risk from carbon resources to other natural resources, in particular critical metals, and a trade-off between increased mining risk and deployment of such technologies. Our analysis constitutes a first step toward quantifying and managing the risks associated with natural resource mining.