What is Carbon Capture, Utilization & Storage (CCUS)? Progress & Roadblocks - Green&Circular Decabonization Solution|MITSUI & CO., LTD.

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Last Update:2025.06.19

What is Carbon Capture, Utilization & Storage (CCUS)? Progress & Roadblocks

This article provides an overview of CCUS—Carbon Capture, Utilization, and Storage—highlighting its environmental benefits and potential to support a sustainable society. It also explores the current status and challenges of CCUS implementation in Japan and abroad.

*日本語でご覧になりたい方は、「CCUSとは?CO2を再利用して排出量削減に導く取り組みを解説!」をご覧ください。

What is CCUS?

CCUS stands for Carbon Capture, Utilization, and Storage. It encompasses technologies that capture carbon dioxide (CO2) from industrial sources, either storing it underground (CCS) or repurposing it for commercial use (CCU).
出典:European Union, Directorate-General for Climate Action (DG CLIMA)
出典:European Union, Directorate-General for Climate Action (DG CLIMA)

What is CCS (Carbon dioxide Capture and Storage)?

CCS is a term that refers to the capture and storage of CO For example, in thermal power generation, which uses fossil fuels such as oil and coal as energy, CO2 is generated during power generation. This is captured by specialized equipment and stored deep underground under pressure. During collection, CO2 is separated from other gases and only CO2 is collected. Instead of dedicated underground tanks, CO2 is stored in porous geological formations such as sandstone reservoirs that have many crevices to hold the gas.

What is CCU (Carbon dioxide Capture and Utilize)?

CCU is a technology that utilizes recovered CO2. It is used as dry ice or as a raw material for concrete, etc. CO2 contributes to greenhouse gas effects only when released into the atmosphere. If CO2 is captured and kept underground or converted into useful products, it effectively reduces emissions.

What is the status of CCUS implementation in Japan and overseas?

CCS in Japan

In Japan, CCS demonstration experiments are currently underway to promote CCUS. The first CCS demonstration in Japan was in Tomakomai, Hokkaido, Japan. After construction and trial operation of the facility, work began in FY2016 to inject and store CO2 under high pressure, and by November 2019 we had succeeded in injecting a cumulative total of 300,000 tons, our storage target. Currently, progress is being monitored using a combination of various methods (e.g., seismic surveys, microvibration observations, etc.) to ensure the safety of CO2 storage.

CCU in Japan

Various efforts are underway in CCU technology to convert CO2 into resources and artificial photosynthesis. Saga City in Saga Prefecture was the first in Japan to install CO2 separation and recovery equipment at a waste incineration plant's waste-to-energy facility, and the recovered CO2 is sold to an algae cultivation company to be commercialized as cosmetics and supplements.

Overseas CCS

Various initiatives are underway overseas, including CO2 storage in depleted oil fields. Japan Australia LNG (MIMI), a joint venture established by Mitsui & Co. and Mitsubishi Corporation (MC), is currently investigating a CCS project in a depleted gas field off the coast of Karratha in northwest Australia, together with four international oil and gas companies (Woodside of Australia, bp of the UK, Shell of the UK, and Chevron of the US).
Mitsui and Shell are also conducting a joint study on the demonstration of CCS and liquefied CO2 carrier in the Asia Pacific region.

Overseas CCU

In the U.S., CO2 is injected into old oil fields to pressure out the remaining crude oil in the oil fields while storing the CO2 underground. Oil fields that have little crude oil remaining will no longer spew crude oil naturally, and utilizing CO2 to properly recover the crude oil leads to increased oil production and contributes to overall CO2 emissions reduction.

What are the challenges to realizing CCUS?

CCS and CCU are very meaningful measures against global warming, but for Japan to realize CCUS, it is necessary to clear three issues: cost, technology, and environment.

Cost of recovering CO2 by separating it from other gases

When storing CO2, it is necessary to separate CO2 from other gases. There are several ways to do this, including using a liquid that absorbs CO2 or using a special membrane to separate only CO2. However, neither method has yet been put to practical use due to technical and cost issues, and both are still in the research stage.
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Technology and cost of reutilizing recovered CO2

While simply storing CO2 from power plants and chemical plants helps reduce emissions, reusing CO2 is more desirable. Carbon recycling technologies convert CO2 into useful products such as synthetic fuels, biofuels, mineralized concrete, and chemicals like urethanes. However, most of these processes require additional energy and materials, such as hydrogen, which is currently expensive. Therefore, reducing these costs is essential for practical application.

Search for geological formations capable of storing sufficient amounts of CO2 for long periods of time

CO2 is stored not in tanks but in large underground geological formations such as porous sandstone layers. Finding suitable formations that can safely store large volumes of CO2 for long periods is critical. In Japan, the Ministry of Economy, Trade and Industry (METI) and the Ministry of the Environment (MOE) are jointly surveying potential storage sites.
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Currently, CCUS is in the experimental stage, and there are still issues to be addressed for its practical application. However, CCUS is attracting attention because if CO2 is utilized as a resource, it will be an initiative that can contribute to CO2 reduction and global warming prevention.

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