INPEX, the largest resource developer, has launched a large-scale project to trap carbon dioxide underground in the Tokyo metropolitan area, in collaboration with Nippon Steel and others. Behind this is the full-scale implementation of CCS (CO2 Capture and Storage) as a “trump card for decarbonization” aimed at achieving the government’s 2030 target.

The Metropolitan Area CCS Project is a grand project that captures carbon dioxide (CO2) emitted from the Keiyo Coastal Industrial Zone along the Tokyo Bay coast and stores it deep underground off the seabed off Sotobo in Chiba Prefecture. To promote this business, on February 28, 2025, INPEX (85% stake) and Kanto Natural Gas Development (15%) established a joint venture called Metropolitan Area CCS Co., Ltd. The main flow of the project is as follows.

• CO2 is separated and captured from Nippon Steel’s East Japan Works Kimitsu area and surrounding factories.

• A trunk pipeline of about 80 km crossing the Boso Peninsula will be laid to transport goods to the Sotobo side.

• CO2 is injected into deep saline layers beneath the seabed off Sotobo in Chiba Prefecture and stored semi-permanently.

The final storage target is set at 5 million tons per year, which corresponds to about 10% of Chiba Prefecture’s total annual emissions. Efforts to store CO2 generated in metropolitan areas near these areas are attracting attention as an advanced model case unprecedented worldwide. Please refer to the business scheme diagram below.

[Background of Management and Strategy] INPEX’s roadmap for decarbonization

In its long-term strategy “INPEX Vision 2035,” announced in February 2025, INPEX has set a goal to balance stable supply of oil and natural gas with decarbonization. The company’s strategic intention to make the CCS business one of its growth engines is to break away from the traditional resource-price-linked business.

The company owns and operates approximately 1,500 km of natural gas pipelines in Japan, and has the strength of directly applying its maintenance technology and underground evaluation and drilling techniques cultivated through years of oil and gas field development to CCS. In the fiscal year ending December 2025, the company has demonstrated strong underlying profitability, securing record-high real profits even against headwinds from falling oil prices, and plans to concentrate this capital on next-generation low-carbon solutions. Of the planned investment of 850 billion yen for 2026, many resources will be allocated to the growth engines of oil, natural gas, and low-carbon sectors, with the Metropolitan Area CCS project positioned as a symbolic initiative.

[Importance as a National Policy] Progress in GX Promotion Strategy and Legal Framework

The Japanese government has approved the “GX (Green Transformation) Promotion Strategy” by fiscal year 2030, aiming to achieve carbon neutrality by 2050, creating an environment that enables private businesses to start CCS. As a pillar supporting this national policy, the “Act on Carbon Dioxide Storage Projects (CCS Business Act)” was enacted in May 2024.

Under this new law, CCS projects will be subject to a permit system, imposing monitoring obligations and security regulations on operators, while establishing “deemed property rights” such as exploration and storage rights to enhance the project’s predictability. Additionally, through the Japan Energy and Metals National Corporation (JOGMEC), nine projects, including the Metropolitan Area CCS Project, were selected as ‘Advanced CCS Projects,’ and a system was launched to provide public support worth trillions of yen for surveys, design, and construction. For companies, government support for cost differentials provides a major boost to overcome profitability challenges and pursue commercialization. Please refer to the conceptual diagram of the CCS long-term roadmap below.

[Technology and Safety] Demonstration Results and Monitoring System for Subsea Storage

The technology to store CO2 underground involves pressing CO2 into a ‘storage layer (such as sandstone)’ at depths of over 1,000 meters, and covering the upper part with a ‘shield layer (such as mudstone)’ to prevent leakage. The safety of this technology has already been proven in large-scale demonstration tests in Tomakomai, Hokkaido.

• At Tomakomai, a cumulative total of 300,000 tons of pressing was successfully completed between 2016 and 2019.

• During the 2018 Hokkaido Eastern Iburi Earthquake (seismic intensity 5 low), no impact on reservoirs or CO2 leakage was detected.

• In addition to 24-hour continuous monitoring of pressure and temperature, CO2 behavior prediction is conducted through elastic wave surveys.

In the Metropolitan Area CCS project as well, Kanto Natural Gas Development will utilize geological data from water-soluble natural gas development that has been accumulated in the Sotobo region since the early Showa period. Furthermore, a strict safety management system will be introduced using the latest technologies such as fiber optic sensing, capturing even the smallest vibrations and changes in strata in real time.

[Social Issues] Local Residents’ Concerns and Transparency in Environmental Impact

On the other hand, local residents remain deeply concerned about the large-scale infrastructure development. In particular, fisheries professionals and coastal residents off the Kujukuri coast, which became a candidate storage site, have expressed concerns about the impact of test drilling and operations on the marine ecosystem and the risk of earthquakes.

International environmental NGOs such as FoE Japan have protested that environmental impact assessments (environmental assessments) are not legally required under the CCS Business Act and that explanations to residents are limited to certain regions. At a resident briefing held in Sodegaura City in July 2025, questions were raised seeking more specific explanations regarding pipeline maintenance responsibilities and compensation systems in the event of natural disasters. The Metropolitan Area CCS Co., Ltd., which is advancing its business, is striving to foster social acceptance through sincere communication, such as publishing the regional newsletter ‘Umito Mirai Tsushin.’ However, further transparency and dialogue are required ahead of the final investment decision at the end of 2026.

[Future Developments & Highlights] Final Investment Decisions in 2026 and the Path to Commercialization

The Metropolitan Area CCS Project is currently in the phases of ‘detailed design’ and ‘storage potential evaluation’ toward commercialization. On July 7, 2026, drilling began for the first test shaft off the coast of Kujukuri, Chiba Prefecture (Kujukuri Offshore J-1). Through this trial drilling, we will obtain actual stratigraphic data and rock samples, and re-verify whether the facility can stably store CO2 over a long period.

Key milestones ahead are as follows:

• End of fiscal year 2026: Based on trial drilling results and detailed design, a final investment decision (FID) will be made to assess the economic and safety of the project.

• From 2027 onward: Infrastructure construction (pipeline laying, press-in equipment construction) will begin.

• Fiscal 2030: Commercial operation will begin, starting with an annual injection capacity of 1.2 million tons.

If this project succeeds, CCS will be established as a practical transition tool in Japan’s core industrial zones, where industries such as steel and chemicals are concentrated in areas where decarbonization is difficult. This challenge, which combines national policy with private technology, holds the potential to significantly transform Japan’s energy structure.

Reference Page

• [Metropolitan Area CCS Project – INPEX] https://www.inpex.com/business/project/metropolitan-ccs.html

• [Metropolitan CCS Co., Ltd.] https://mccs.inpex.co.jp/

• [Regarding the Act on Carbon Dioxide Storage Businesses, etc. – Ministry of the Environment] https://www.env.go.jp/council/06water/y060-72/mat07.pdf

• [Large-scale CCS Demonstration Test in Tomakomai – Ministry of the Environment] https://www.env.go.jp/earth/ccs/m_tomakomai.html

• 【INPEX Vision 2035】https://www.inpex.com/company/midterm.html

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