Breakthrough technology helps reduce greenhouse gas emissions

In the context of the Earth's climate warming due to CO2 emissions causing the greenhouse effect, the development of technologies to reduce the amount of CO2 emitted into the atmosphere is attracting special attention from the world.

A corner of the CCS technology experimental plant in Tomakomai seen from above. (Photo: Nguyen Tuyen/Vietnam+)

CO2 capture and storage (CCS), a technology that separates and recovers CO2 from emissions from factories and then stores it in an underground system under the seabed, is being evaluated by scientists as one of the technologies with potential to achieve this goal.

The Japanese government included CO2 capture and storage in its April 2014 Strategic Energy Plan and hopes that the technology will help reduce CO2 emissions from thermal power plants that burn fossil fuels such as coal and from steel mills, cement plants, chemical plants and many other industries.

With the goal of making CO2 capture and storage a common technology by 2020, in April 2012, the Japanese Ministry of Economy, Trade and Industry commissioned the Japan CO2 Capture and Storage Corporation (established in August 2008 with funding from companies involved in fields such as electric power, natural gas and petroleum) to conduct a pilot project on CO2 capture and storage.

Japan's first large-scale CO2 capture and storage experimental project, the Tomakomai CO2 Capture and Storage Experimental Center, was established with about 100 employees and a total operating capital of 243 million yen.

To implement this project, 35 enterprises participated as shareholders, including electricity, engineering, petroleum, cement, iron, steel, gas, metal, etc.

The project aims to test CO2 capture and storage technology to verify safety issues such as earthquakes will not affect the safety of CO2 storage, CO2 injection will not cause geological tremors, stored CO2 will not leak, etc.

A CO2 injection site into a reservoir is 3-4km from the mainland. (Photo: Nguyen Tuyen/VNA)

The Tomakomai CO2 Capture and Storage Project was carried out with local cooperation and received international attention for its advanced CO2 capture and storage technology applications such as reducing the energy used to separate and capture CO2, injecting CO2 directly from land to offshore reservoirs, and monitoring geological changes in the ocean through an underground measurement system.

Offshore reservoirs can be porous geological layers through which air can pass, such as aquifers, sandstone structures, or oil and gas fields at depths below 1,000m.

After being pumped into underground tanks, CO2 will be prevented from leaking back up by thick, impermeable layers of rock (limestone, mudstone) to ensure that CO2 will be stored safely and stably.

Therefore, geological structure including porous rock layers suitable for CO2 storage and overlapping layers of gypsum or limestone to prevent CO2 from leaking back up is a mandatory factor in choosing a site to build a CO2 capture and storage plant.

This is the reason why, from more than 115 proposed locations, Tomakomai was chosen as the site for Japan's CO2 capture and storage project, thanks to comprehensive investigations showing that the structure and geological formation of the land are completely suitable.

According to estimates by the Earth Innovation Technology Research Institute, Japan could store 146.1 billion tons of carbon, equivalent to 100 years of emissions.

The CO2 injection into offshore tanks was carried out from April 2016 with a volume of 300,000 tons of CO2 injected into one of two tanks at a depth of 1,000 to 2,000 meters below the seabed, off the port of Tomakomai.

CO2 injection is expected to be conducted over three years until 2018 and monitored for five years until 2020.

Scientists say CO2 capture and storage technology could reduce 5.5 billion tons of CO2, equivalent to 16% of the amount of CO2 needed to limit the Earth's temperature increase to below 2 degrees Celsius compared to pre-industrial temperatures.

CO2 recovery system. (Photo: Nguyen Tuyen/Vietnam+)

Several large-scale CO2 capture and storage projects are underway in countries such as Norway, Canada, the US and Brazil.

According to the International Energy Agency, CO2 capture and storage is expected to reduce global CO2 emissions by 13% by 2050.

Therefore, CO2 capture and storage technology is expected to be one of the potential solutions to address climate change.

According to Vietnam+