Initiatives to Help Build a Decarbonized Society





Initiatives to Build a Decarbonized Society

Products and Services that Contribute to Building a Decarbonized Society

For the Group, tackling climate change has been one of its most important management issues for building a decarbonized society. Reflecting this, the Group has been approaching manufacturing with a view to reducing the environmental impact and has developed and promoted the use of renewable sources of energy, such as geothermal energy.

“Fire-Resistant Plastic,” a New Lightweight Fire-Resistant Material That Will Not Burn or Melt When Exposed to Flames

photoMolded fire-resistant plastic

In recent years, lithium-ion batteries (LIBs) for electric vehicles (EVs) have become increasingly dense, increasing the risks in case of LIBs catching fire. At the same time, there are demands for vehicle bodies to be made lighter in order to extend their range.
Plastic materials are used in various products to reduce weight, and today flame-resistant plastics are widely marketed for their fire proof properties. However, conventional flame-retardant plastics have difficulty withstanding hot fires, and metal continues to be used in components where safety is a priority, and this has been hindering progress in weight reductions.
Mitsubishi Materials Corporation has developed a technology that achieves an easily moldable “fire-resistant plastic” that does not burn or melt easily when exposed to flames while being lightweight. When used in components such as the LIB case lid in an EV, it is expected to prevent a fire from spreading in the event of ignition. Going forward, we will pursue the commercialization of products that utilize this technology.

Creation of a High-efficiency Thermoelectric Power Generation Technology, an Innovative Thermal Management Technology

photoThermoelectric power generation module

Thermoelectric power generation technologies* which make effective use of unused and waste heat are expected to undergo widespread adoption to achieve carbon neutrality. To achieve significant greenhouse gas (GHG) reduction effects at a low energy generation cost, thermoelectric power generation elements and modules with a high conversion efficiency are needed.
Mitsubishi Materials Corporation has implemented a unique material design that differs from conventional approaches and used environmentally friendly materials in an effort to create a thermoelectric power generation technology with performance that surpasses conventional approaches while featuring high long-term reliability, and has been pursuing development aimed at achieving a conversion efficiency on par with solar power generation. If this technology is practically implemented, it could be deployed for a wide range of applications from equipment management at factories to vehicles and IoT communications equipment, and is expected to enable functions that have traditionally proven difficult, such as driving electrical equipment and selling electricity to the grid through thermoelectric generation alone. We will continue to pursue business development with the aim of achieving practical utilization of this innovative thermal management technology.

  • Thermoelectric Power Generation Technologies: Technologies that utilize temperature differences to convert thermal energy into electrical energy.
Successfully Synthesizing a New Tin Oxide Exhibiting Photocatalytic Properties in Visible Light

photoCrystalline structure and electron structure of orthorhombic Sn3O4Source: Y.S. Liu, et al., Angew. Chem. Int. Ed. 2023, 62, e202300640

In joint research, a research group led by Professor Miyauchi of the Tokyo Institute of Technology that includes Mitsubishi Materials Corporation and Associate Professor Tanabe of the National Defense Academy successfully synthesized an orthorhombic tin tetraoxide (Sn3O4), a tin with a new crystalline structure, and managed to determine the mechanism of its functional expression by first-principle calculations.
Low cost and stable semiconductors that exhibit photocatalytic properties to absorb visible light are essential for the practical utilization of artificial light synthesis, and monoclinic Sn3O4 had been reported as one such semiconductor. However in this research, the hitherto unreported orthorhombic Sn3O4 was synthesized using a simple hydrothermal method. This orthorhombic Sn3O4 is able to absorb a wider range of visible light than conventional tin oxide, and due to its high conduction band level and strong excited electron reducing capacity, it functions as a photocatalyst able to reduce carbon dioxide. The research also found that control of the hydrothermal synthesis conditions made it possible to create different crystalline polymorphs. This knowledge is expected to lead to the synthesis of crystalline polymorphs and new materials other than as yet unreported tin oxides.

Endorsement of the Ministry of Economy, Trade and Industry (METI)'s GX League Basic Concept

We have endorsed the GX League Basic Concept announced by the Ministry of Economy, Trade and Industry since April 2022, and later in  2023 submitted a note of confirmation aimed at participation in the GX League Emissions Trading Scheme (GX-ETS). The GX League was established as a forum where companies actively engaged in GX (Green Transformation), together with government agencies, universities, public research institutions, financial institutions, and other players taking up the challenge of GX, can work as one to discuss the transformation of the entire economic and social system and to practice the creation of new markets. The GX Forum was established to provide a forum for discussion and practice for the creation of new markets for the transformation of the entire economic and social system. Participating companies are expected to play a leading role in the realization of carbon neutrality, not only through their own efforts to reduce emissions, but also by collaborating with a wide range of actors, including supply chain companies, consumers, and civil society. We are also involved in efforts to reduce emissions, including encouraging companies in our supply chain to do so. In the process of discussions toward the establishment of an emissions trading system (GX-ETS) promoted by the GX League, we are also providing comments and opinions to help make the system even better.


Producing Renewable Energy

We have been developing renewable energy sources to supply the electricity needed for our mines and smelters. To date, we have been promoting the creation of renewable energy sources, mainly geothermal and hydroelectric power generation, in order to provide a stable supply of energy with minimal environmental impact, utilizing the expertise we have accumulated.


Geothermal Power Generation Business

Activities for the Stable Operation of Existing Power Plants

We stably generate environmental loading-reducing electric power through our Onuma Geothermal Plant and Sumikawa Geothermal Power Station (steam supply only, power generated by Tohoku Electric Power Co., Inc.), both in the Hachimantai area of Kazuno, Akita prefecture, as well as the Wasabizawa Geothermal Power Plant (owned by Yuzawa Geothermal Power Corporation, established jointly with Electric Power Development Co., Ltd. and Mitsubishi Gas Chemical Company, Inc.), which began commercial operation on May 20, 2019 in the Takamatsu and Akinomiya areas of Yuzawa, Akita prefecture. In fiscal 2023, we generated a total of 604 GWh of power (including 322 GWh from plants in which we have equity stake, etc.). The operation of our geothermal plants and steam supply systems effectively reduced CO2 emissions by approx. 136,000 tons (calculated based on emissions from Sumikawa Geothermal Power Station of Tohoku Electric Power Co., Inc. and our equity stake in Wasabizawa Geothermal Power Plant of Yuzawa Geothermal Power Corporation).
In geothermal power generation, it is important to understand the unseen underground conditions to ensure a continuous and stable supply of steam. At the Sumikawa geothermal power plant, we will continue to monitor the underground conditions through detailed verification of data since the start of operation and reanalysis of the geological structure in order to improve the amount of electricity generated and continue stable operations at the site. We are working to maintain a geothermal reservoir at the Sumikawa Geothermal Area, with the aim of increasing the amount of power generated in the future. We have been verifying data in detail, and reanalyzing geothermal systems since we started operations at the site, as we continue to focus on maintaining stable operations.

Activities for New Geothermal Development

In addition to operating these geothermal plants, we are currently working on new projects, too. Yuzawa Geothermal Power Corporation, established jointly with Electric Power Development Co., Ltd. and Mitsubishi Gas Chemical Company, Inc. started construction of Wasabizawa Geothermal Power Plant in May 2015 and began commercial operation of this plant on May 20, 2019. In October 2015, we established Appi Geothermal Energy Corporation in conjunction with Mitsubishi Gas Chemical Company, Inc. We were joined by Electric Power Development Co., Ltd. in June 2018. The three companies are promoting commercialization and started construction in August 2019. In August 2021, we launched a survey to quantify the geothermal resources in the Komonomori area (Kazuno), which is located northeast of the Onuma Geothermal Power Station, using subsidies from the Japan Oil, Gas and Metals National Corporation (JOGMEC). Further, we have begun a survey to quantify the geothermal resources in the upstream area of the Appi River (Hachimantai), which is east of the Appi Geothermal Power Plant, in June 2022 using subsidies from JOGMEC. Additionally in May 2022, we invested in Hakodate Esan Geothermal G.K., which is conducting geothermal surveys and development in the Esan area (Hakodate) and are involved in the construction of a geothermal power plant with RENOVA, Inc. and Daiwa Energy & Infrastructure Co. Ltd., which will begin after the resource surveys and environmental impact assessments have been completed. We are also continuing to conduct joint surveys with other companies in the Azuma-Adatara area of Fukushima prefecture.

Wasabizawa Geothermal Power PlantWasabizawa Geothermal Power Plant (Akita prefecture)
Main business operator: Yuzawa Geothermal Corporation
Operation commenced in May 2019
Output: 46,199kW

Appi Geothermal Power PlantAppi Geothermal Power Plant (Iwate prefecture)
Main business operator: Appi Geothermal Energy Corporation
Operations scheduled to commence in April 2024
Output: 14,900kW

Participation in a New Geothermal Development Project in the Esan Area, Hakodate City, Hokkaido

In May 2022, we have invested in Hakodate Esan Geothermal LLC (Esan Geothermal) as a new business partner of RENOVA, Inc. (Chuo-ku, Tokyo; Founding CEO, Yosuke Kiminami) and Daiwa Energy & Infrastructure Co. Ltd. (Chiyoda-ku, Tokyo; President, Morimasa Matsuda). Since its establishment in 2016, Esan Geothermal has moved ahead with business development with the aim of developing a new geothermal power plant in the Esan area of Hakodate City, Hokkaido.
We are utilizing the abundant experience and high technological capabilities we have cultivated over many years through our development and management of coal and metal mines for hydroelectric and geothermal power generation. In relation to geothermal power generation, since Onuma Geothermal Power Plant (Akita Prefecture) started operation in 1974, we have played a central role in the construction and operation of Sumikawa Geothermal Power Plant (Akita Prefecture, operation started in 1995), Wasabizawa Geothermal Power Plant (Akita Prefecture, operation started in 2019), and Appi Geothermal Power Plant (Iwate Prefecture, operation scheduled to start in 2024).
We have been working on the "development and promotion of the use of renewable energies such as geothermal energy" and intend to engage in this project by making use of our experience and technological capabilities through investment to contribute to the success of the project.

photoAn excavation survey

Hydroelectric Power Generation Businesses

We have a long history of generating hydroelectric power, dating back to 1898, when we built seven hydroelectric power plants in Akita prefecture, for the purpose of supplying enough power to run Osarizawa Mine (opened as a gold mine, later operated as a copper mine, closed in 1978) and homes in the local area. We were compensated for one of those power plants when a dam was built and the plant was submerged in 2000. The remaining six however are still operating today, selling all of the power that they generate to a power company. Since 2014, we have successfully completed upgrades at three hydroelectric power plants, in an effort to deal with aging facilities. We also completed updates at Oyu Hydroelectric Power Plant (Kazuno) in March 2018. In addition, in May 2019, we began to construct the New Komatagawa Hydroelectric Power Plant in the Komata River system in Kita-Akita City, Akita. It is the first new hydroelectric power plant since the No. 4 Komatagawa Hydroelectric Power Plant, which was completed in 1953. The new plant is scheduled to start operating in December 2022. We also began investigations in multiple places since fiscal 2022, with the goal of constructing new small-scale hydropower plants with an output of around 1,000 kW each.
In fiscal 2023, the combined total of power generated by all six hydroelectric power plants was 92 GWh. Our operation of hydroelectric power plants effectively reduced CO2 emissions by approx. 40,000 tons.

Komatagawa New Power PlantKomatagawa New Power Plant (Akita prefecture)
Main business operator: Mitsubishi Materials Corporation
Operation commenced in December 2022
Output: 10,326kW

Solar Power Businesses

Since 2013 we have been working on a new solar power business, making effective use of idle Group land. By 2017 we had built power plants in five locations as part of a joint venture with Mitsubishi HC Capital Inc. We are currently operating plants in Makabe (Ibaraki prefecture), Fukui, Torigoe (Fukuoka prefecture), Irigama (Miyagi prefecture), and Yabuki (Fukushima prefecture). In fiscal 2023, the combined total of power generated by all five solar power plants was 28 GWh (including 14 GWh from power plants in which we have equity stakes). The operation of these power plants (in which we have equity stakes) effectively reduced CO2 emissions by approx. 10,000 tons.

Irigama Solar Power StationIrigama Solar Power Station (Miyagi prefecture)
Main business operator: LM Sun Power CO., Ltd.
Operation commenced in January 2015
Output: 6,930kW

Biogas Power Generation Business

We conduct power generation using biogas obtained from the processing of food waste at New Energy Fujimino Co., Ltd., a consolidated subsidiary established in 2018. The power generation has an output of 550 kW. In the fiscal year 2023, the electricity generated through biogas power generation amounted to 2 GWh (of which our share was 2 GWh).


Renewable Energy's Effect on the Reduction of CO2 Emissions

Reduction in CO2 Emissions Using Renewable Energy (reflecting our equity in power plants)


  • Recalculated based on the CO2 emission factor for commercial electric power defined by METI

Renewable Energy Power Generation Targets and Results


  • Steam supply to geothermal power plants (steam sales converted by electric energy volume)


Ground Source Heat Pump Systems (GSHP)

Helping to Build of a Decarbonized Society by Promoting Ground Source Heat Utilization, Which is Renewable Energy Heat.

In 2000, Mitsubishi Materials Techno Corporation entered the business of ground-source heat, which is heat from a renewable energy source, as a provider of total engineering solutions. The company has been providing services in the process from project proposal through investigation, design, construction, and maintenance.
The company has continued its R&D efforts and acquired patented technologies through projects commissioned by the government and others, aiming to become the No.1 company in geothermal technologies. As a result, the company has succeeded in building infrastructure using ground-source heat by developing commercial systems with various heat exchange methods, including not only the common borehole method but also its patented foundation pile method as well as horizontal and earth retaining wall methods. At present, Mitsubishi Materials Techno Corporation is promoting sales of these technologies as systems for using ground-source heat utilized through urban infrastructure, aiming to contribute to smart cities in the future.
Approx. 130 systems from the company have been installed. Since 2020, the large-scale utilization of ground-source heat has been increasing. For example, the company completed one of the largest projects in Japan, which combines the borehole method (100 m in depth x 120 boreholes) and the horizontal method (nine units x approx. 100 m long trenches), at a city hospital in Hachimantai. It also completed one of the largest projects in the Tokyo metropolitan area, which applied the foundation pile method (66 cast-in-place piles) at the Yokohama City Hall. In May 2022, Mitsubishi Materials Techno Corporation, the Yokohama City Government, Takenaka Corporation, and other companies received the 60th Gakkai-sho Gijutsu-sho (academic society award and technology award) in the building equipment category from the Society of Heating, Air-Conditioning and Sanitary Engineers of Japan for the implementation of the Yokohama City Hall environmental and facility plans. The company will continue to help establish a decarbonized society by expanding the use of ground-source heat as renewable energy.

Overview of the System for Using Ground-Source Heat Utilized through Urban Infrastructure

Heat Exchange Systems and Examples of Projects Which Adopted Them


Carbon dioxide Capture, Utilization and Storage (CCUS)

For Carbon dioxide Capture, Utilization and Storage (CCUS)

Concerning carbon dioxide capture and storage, we invested in Japan CCS Co., Ltd., which was established in May 2008. Through Japan CCS, we are participating in the Large-scale CCS Demonstration Project in Tomakomai and Investigation of Potential Sites for CO2 Storage. Regarding carbon dioxide capture and utilization, we have launched a demonstration test recovering carbon dioxide emitted from the Group’s plant. (See the link below for details.)

  • This data is only available in Japanese on the website.