2022/01/28 更新

写真a

ジュ イイ
居 乂義
所属
附属機関・学校 高等研究所
職名
講師(任期付)

兼担

  • 社会科学総合学術院   社会科学部

学歴

  • 2016年10月
    -
    2019年09月

    名古屋大学   大学院国際開発研究科  

経歴

  • 2021年04月
    -
    継続中

    早稲田大学   高等研究所   任期付講師

  • 2020年11月
    -
    2021年03月

    東京大学   未来ビジョン研究センター

  • 2019年10月
    -
    2020年10月

    東京大学   未来ビジョン研究センター

所属学協会

  • 2017年04月
    -
    継続中

    環太平洋産業連関分析学会 (PAPAIOS)

  • 2017年04月
    -
    継続中

    環境経済・政策学会 (SEEPS)

 

研究分野

  • 環境政策、環境配慮型社会

研究キーワード

  • 産業脱炭

  • エネルギー・経済統合評価モデル

  • 気候政策

論文

  • An open-source tool for visualization of climate mitigation scenarios: Mipplot

    Yiyi Ju, Masahiro Sugiyama, Diego Silva Herran, Jiayang Wang, Akimitsu Inoue

    Environmental Modelling & Software   139   105001 - 105001  2021年05月

    DOI

  • Industrial decarbonization under Japan’s national mitigation scenarios: a multi-model analysis

    Yiyi Ju, Masahiro Sugiyama, Etsushi Kato, Yuhji Matsuo, Ken Oshiro, Diego Silva Herran

    Sustainability Science    2021年

     概要を見る

    © 2021, The Author(s). Energy-intensive industries are difficult to decarbonize. They present a major challenge to the emerging countries that are currently in the midst of rapid industrialization and urbanization. This is also applicable to Japan, a developed economy, which retains a large presence in heavy industries compared to other developed economies. In this paper, the results obtained from four energy-economic and integrated assessment models were utilized to explore climate mitigation scenarios of Japan’s industries by 2050. The results reveal that: (i) Japan’s share of emissions from industries may increase by 2050, highlighting the difficulties in achieving industrial decarbonization under the prevailing industrial policies; (ii) the emission reduction in steelmaking will play a key role, which can be achieved by the implementation of carbon capture and expansion of hydrogen technologies after 2040; (iii) even under mitigation scenarios, electrification and the use of biomass use in Japan’s industries will continue to be limited in 2050, suggesting a low possibility of large-scale fuel switching or end-use decarbonization. After stocktaking of the current industry-sector modeling in integrated assessment models, we found that such limited uptake of cleaner fuels in the results may be related to the limited interests of both participating models and industry stakeholders in Japan, specifically the interests on the technologies that are still at the early stage of development but with high reduction potential. It is crucial to upgrade research and development activities to enable future industry-sector mitigation as well as to improve modeling capabilities of energy end-use technologies in integrated assessment models.

    DOI

  • Revealing the impact of a projected emission trading scheme on the production technology upgrading in the cement industry in China: An LCA-RCOT model

    Yiyi Ju, Kiyoshi Fujikawa

    Resources, Conservation and Recycling: X   4  2019年12月

     概要を見る

    © 2019 The Author(s) The cement industry in China has been conducting overcapacity elimination through technology upgrading in the past years. Most of the overcapacity elimination policies are in the form of administrative and regulative approaches. However, the cost of overcapacity elimination by implementing command-and-control policies will be increasingly higher, at the same time, the orientation of such technology upgrading remains unknown. Such contradiction creates the necessities to reveal the impact of other policy instruments on the technology upgrading in the cement industry, as well as to clarify the optimal output allocation among all alternative technology choices. In this paper, an LCA-RCOT model (Life Cycle Assessment and Rectangular Choices Of Technologies) is established to provide such optimal technology combination with the constraints from a projected emission trading scheme (ETS). The results show that under an ETS cap with a target of 5% reduction of emission, 10% of subsidy allowances, and one-way linking with another ETS with higher average market price, the optimal solution suggest that 114.5 billion USD of total output in the cement sector should be produced by small dry kilns, while 102.5 billion USD by large dry kilns. In all feasible solutions, the optimal technology combination may shift to fewer shaft kilns and more dry kilns. In the long run, the climate policy instrument, ETS, may promote the upgrading of production technology by decomposing the total emission mitigation costs to the factor inputs of each cement producer.

    DOI

  • EMF 35 JMIP study for Japan’s long-term climate and energy policy: scenario designs and key findings

    Masahiro Sugiyama, Shinichiro Fujimori, Kenichi Wada, Ken Oshiro, Etsushi Kato, Ryoichi Komiyama, Diego Silva Herran, Yuhji Matsuo, Hiroto Shiraki, Yiyi Ju

    Sustainability Science   16 ( 2 ) 355 - 374  2021年

     概要を見る

    © 2021, The Author(s). In June, 2019, Japan submitted its mid-century strategy to the United Nations Framework Convention on Climate Change and pledged 80% emissions cuts by 2050. The strategy has not gone through a systematic analysis, however. The present study, Stanford Energy Modeling Forum (EMF) 35 Japan Model Intercomparison project (JMIP), employs five energy-economic and integrated assessment models to evaluate the nationally determined contribution and mid-century strategy of Japan. EMF 35 JMIP conducts a suite of sensitivity analyses on dimensions including emissions constraints, technology availability, and demand projections. The results confirm that Japan needs to deploy all of its mitigation strategies at a substantial scale, including energy efficiency, electricity decarbonization, and end-use electrification. Moreover, they suggest that with the absence of structural changes in the economy, heavy industries will be one of the hardest to decarbonize. Partitioning of the sum of squares based on a two-way analysis of variance (ANOVA) reconfirms that mitigation strategies, such as energy efficiency and electrification, are fairly robust across models and scenarios, but that the cost metrics are uncertain. There is a wide gap of policy strength and breadth between the current policy instruments and those suggested by the models. Japan should strengthen its climate action in all aspects of society and economy to achieve its long-term target.

    DOI

  • アジアの脱炭素化のためのエネルギー・モデル連携に向けて

    杉山昌広, 居乂義, 滕飛, Yong-Gun Kim, 蘇斌

    環境経済・政策研究   13 ( 2 ) 85 - 88  2020年09月

  • The potential and trend of end-of-life passenger vehicles recycling in China

    Yang Li, Kiyoshi Fujikawa, Junbo Wang, Xin Li, Yiyi Ju, Chenyi Chen

    Sustainability (Switzerland)   12 ( 4 ) 1 - 13  2020年02月

     概要を見る

    © 2020 by the author. The contradiction between limited resources and rapid development in the automobile industry has been driving society to seek the supply of recyclable resources from End-of-Life Vehicles (ELVs). It has become an urgent need for vehicle recycling policymakers to have an overall understanding of the end-of-life (EoL) vehicle population, as well as for vehicle producers to note what and how they can benefit from ELV recycling. This paper estimated the potential population of EoL passenger vehicles, all recyclable resources from them, as well as the economic values of these recyclable resources. The results show that in 2030, with a lighter-weight trend of passenger vehicles, more than 26.3 million passenger vehicles will be retired with 19.1 million tons of recyclable steel and 6.2 million tons of plastics. The theoretical economic value of all recyclable resources will reach 101.3 billion yuan ($14.4 billion) in 2030, which is an average of approximately 2.4 thousand yuan ($341.8) for each EoL passenger vehicle. It is time for the vehicle producers to shift to a manufacturing mode considering such large potential of ELV recycling. The scenario analysis suggests that in the context of a light-weighting trend, ELV resource recovery in the future calls for improvement in the recycling and reuse technologies of plastics and rubbers.

    DOI

  • Scenario analysis of the recycled copper supply in China considering the recycling efficiency rate and waste import regulations

    Junbo Wang, Yiyi Ju, Minxi Wang, Xin Li

    Resources, Conservation and Recycling   146   580 - 589  2019年07月

     概要を見る

    © 2019 Elsevier B.V. The rapid economic growth and industrialization in China has induced a large copper demand since 1990, of which only approximately 40% is met by domestic ore deposits. However, a high dependence on imported copper ores, refined copper, or copper scrap can pose great risks to the sustainable copper resource supply and economic development of one country. An assessment of the in-use stock of refined copper is essential to estimate the potential supply of recycled copper, especially for countries with a high external dependence, such as China. A scenario analysis may further evaluate such a supply under different development pathways in the context of the increasingly strict import regulation of copper-containing end-of-use products. We introduced Material Flow Analysis and the Weibull lifetime distribution to estimate the in-use stock of refined copper from 1990 to 2035 in China based on the time-series data for sectoral refined copper consumption. The results show that the amount of generated copper scrap has been increasing from 1990 and reached 3.67 Tg in 2016, with 34.4% from the home appliances sector (mainly air-conditioning)and 26.6% from the power infrastructure sector. In 2035, the total would reach 17.7 Tg, with 42.8% from the power infrastructure sector and 19.7% from the home appliances sector. A scenario analysis was conducted considering different consumption growth rates, waste import regulation standards, and domestic recycling efficiency growth rates. The results show that under both scenarios, a total ban and limited imports of metal-containing scraps, the growth of the domestic recycling efficiency may improve the refined copper supply, which would be 0.867 Tg (67.4%)and 1.04 Tg (80.9%), respectively. With an adequate in-use stock of refined copper and an increasing recycling efficiency rate, domestic recycled secondary copper can cover the shrinking import source of copper scrap and become an essential source to meet the needs of the booming refined copper consumption in China.

    DOI

  • Modeling the cost transmission mechanism of the emission trading scheme in China

    Yiyi Ju, Kiyoshi Fujikawa

    Applied Energy   236   172 - 182  2019年02月

     概要を見る

    © 2018 Elsevier Ltd The national emission trading scheme (ETS) in China, CHN-ETS, was established in 2017 following the start of its regional pilot markets in 2013. It will start with a coverage of electricity supply sector and eight pilot regions. Due to a highly regulated dispatch and pricing system in the electricity supply sector, the additional emission abatement costs brought by the ETS cannot be automatically conveyed between consumers and producers in all regions. This paper modeled the cost transmission of ETS in three scenarios based on the quantification results of regional and sectoral emission flows in the electricity supply sector under consumption-based accounting. The results show that the emissions transferred into pilot cities outweighed the emissions transferred out, not only through direct electricity uses but also through the indirect emissions embodied in other sectors that required intermediate inputs from electricity supply sectors in the pilot cities. Through the cost transmission mechanism, the additional abatement cost caused by the national ETS drove the increases in the household consumption of several energy-intensive sectors, including the metal mining sector in Hebei, the petroleum and gas sector in Heilongjiang, and the nonmetal mining sector in Sichuan, with a sensitive increase of 10.1%, 9.9%, and 3.5%, respectively. However, most sectors (745 of the 810) would suffer an increase rate below 0.1%. As long as the household welfare would be ensured, there is still room for the current average market price in the pilot cities to be further increased toward the official guidance price in the nation-wide market.

    DOI

  • Revealing the bilateral dependencies and policy implication of food production of Japan and China: From the perspective of Food-Energy-Water nexus

    Yiyi Ju

    Ecological Modelling   391   29 - 39  2019年01月

     概要を見る

    © 2018 Elsevier B.V. The world food price crisis in 2007/08 has aroused worldwide attention to the global food price volatility and food self-sufficiency issues. This paper modelled the entire environment of food production and transaction from a holistic view by a Food-Energy-Water (FEW) nexus in order to reveal the hidden connections related to the food self-sufficiency issue, including the interdependencies of food production with its restraining factors (hybrid energy, hybrid water), other production sectors, and international exchanges. This paper mapped all direct and indirect flows in the FEW nexus and projected a potential Emission Trading Scheme (ETS) to figure out the impacts of policies on FEW nexus flows, nexus robustness, total input of all sectors, and household expenditures in Japan and China. The results show that the pattern of food-related extraction flows was more imbalanced than the pattern of hybrid energy flows, due to the high dependence of Japan on the food supply of China (16.11% of total food-related extractions). An ETS may increase Japan's total household expenditure on imported goods from China in the fields of sugar refining (1.3096%), processing vegetable oils and fats (0.1164%), processing of meat cattle (0.1010%), as well as slightly decrease the system robustness of the total nexus.

    DOI

  • City-level features of energy footprints and carbon dioxide emissions in Sichuan province of China

    Junbo Wang, Liu Chen, Lu Chen, Xiaohui Zhao, Minxi Wang, Yiyi Ju, Li Xin

    Energies   12 ( 10 )  2019年

     概要を見る

    © 2019 by the authors. Licensee MDPI, Basel, Switzerland. The sustainable development of the western region of China has always been essential to the national development strategy. The Western region has undertaken an industrial transfer from the Eastern and Central regions. Therefore, the CO2 emission intensity in the western region is higher than those of the Eastern and Central regions of China, and consequently its low-carbon development pathway has an important impact for China as a whole. Sichuan Province is not only the province with the highest CO2 emissions, but also the most economically developed province in Western China in 2018. In order to promote low carbon development in the western region, it is important to understand the features of emissions in Sichuan Province and to formulate effective energy strategies accordingly. This paper uses the IPCC regional emission accounting method to calculate the carbon emissions of 15 cities in Sichuan province, and to comply with the city-level emission accounts. The results show that the total carbon emissions of Sichuan province over the past 10 years was 3258.32 mt and reached a peak in 2012. The smelting and pressing of ferrous metals, coal mining and dressing were the leading sectors that contributed to the emissions, accounting for 17.86% and 15.82%, respectively. Raw coal, cleaned coal, and coke were the most significant contributors to CO2 emissions, accounting for 43.73%, 9.55%, and 6.60%, respectively. Following the above results, the Sichuan provincial government can formulate differentiated energy structure policies according to different energy consumption structures and carbon emission levels in the 15 cities. By controlling the level of total emissions and regulating larger industrial emitters in Sichuan province, some useful information could be provided as an essential reference for low-carbon development in Western China, and contribute to the promotion of emissions mitigation from a more holistic perspective.

    DOI

  • Tracking the PM2.5 inventories embodied in the trade among China, Japan and Korea

    Yiyi Ju

    Journal of Economic Structures   6 ( 1 ) 1 - 16  2016年

     概要を見る

    © The Author(s) 2017. Due to its long-term negative health effects and increasing emissions, the PM2.5 issue has caused rising concerns in recent years. Although official media from East Asian countries tend to avoid blaming PM emission sources on their neighboring countries, researches have proved the existence of pronounced long-range trans-boundary particulate matters transported by nature force and by human activities. In this con-text, this paper included the structural path analysis (SPA) to quantify trans-boundary PM2.5 at sector level, track its transaction paths and figure out the linkages between consumption and production responsibilities of China, Japan and Korea. Based on the results and policy reviews of current environmental cooperation mechanisms, this paper found that: Considering the China–Japan and China–Korea trades, China’s net exportation of embodied PM2.5 emissions has exceeded the importation rates over 10 times (CHN → JPN, 56.53 kt, JPN → CHN, 3.58 kt; CHN → KOR, 59.19 kt, KOR → CHN, 5.31 kt). Japan and Korea benefited from importing raw materials with high emission intensity from China to meet domestic consumption needs and keep a low national emission level. China, the largest emitter in the world, should first take the responsibility to mitigate its huge domestic PM2.5 emission. However, the relocated emissions from its neighboring countries should not be ignored. For Japan or Korea, due to the close economic interdependence and geographical position, any contribution to the reduction of the trans-boundary emissions or to the solution of atmosphere problems within China also helps those countries themselves. In the long run, all three countries would benefit from enhancing subregional environmental cooperation.

    DOI

▼全件表示

書籍等出版物

  • China’s Carbon-Energy Policy and Asia’s Energy Transition Carbon Leakage, Relocation and Halos

    Edited By Akihisa Mori( 担当: 共著,  担当範囲: Chapter 11., Generating or receiving carbon leakages?: An examination of China in Asia Le Tuyet Vo and Yiyi Ju)

    Routledge  2021年12月

共同研究・競争的資金等の研究課題

  • 石炭投融資撤退による環境・経済・経営持続性への移行:アジアの事例分析

    日本学術振興会  科学研究費助成事業 基盤研究(A)

    研究期間:

    2021年04月
    -
    2025年03月
     

    森 晶寿

 

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