Offshore China boasts huge potential for carbon capture and storage, but how to translate that possibility to reality will require concerted efforts among major carbon dioxide emitters such as power utilities and offshore oil and gas operators and contractors.

The latest survey by upstream watchdog the Ministry of Natural Resources (MNR), shows that offshore China has the potential to store up to 2.58 trillion tonnes of CO2.

According to the survey, offshore China hosts many vast sedimentary basins featuring thick strata and stratigraphic traps with stable crust, which are suitable for CO2 storage.

It identified geologic formations for potential storage in Bohai Bay, the East China Sea and the South China Sea through validated modelling, simulation and monitoring tools.

The MNR will further appraise these structures and look for target areas for pilot offshore CCS projects based on the survey.

The survey provides an offshore CCS alternative to achieve China’s targets for CO2 emissions peak in 2030 and carbon neutrality in 2060.

However, even though the offshore offers additional capacity, China will need first to address the technical issues for permanent storage by pumping CO2 into deep saline aquifers or depleted oil and gas fields offshore.

Industry officials said that if China is serious in pursuing offshore geological carbon storage, thousands of wells will need to be drilled and storage operations must abide by strict environmental protection rules.

China now operates about 40 onshore CCS projects in 19 provinces, with CO2 capture capacity of 3 million tonnes per year.

Of the total, 13 are related to power generation and cement production, with CO2 capture capacity of 860,000 tpa.

Eleven are involved with oil and gas production, with a capacity of 1.82 million tpa, including 1.54 million tpa used in enhanced oil recovery projects.

Most of these projects capture CO2 from industrial sources such as plants producing gas-fired power, petrochemicals, coal-based chemicals or iron and steel.

China National Offshore Oil Corporation (CNOOC) has also rolled out plans to develop a number of CCS hubs in southern China’s Guangdong province, where only one offshore project is under development.

In Guangdong, CNOOC has mapped out a phased development for CCS, beginning with its first offshore CCS project at the Enping oilfield in the Pearl River Mouth basin, to be followed by a few more schemes in the Beibu Gulf of the South China Sea.

CNOOC says the Enping project will be expanded to capture CO2 from petrochemical and power operations in the Daya Bay area of Guangdong, 76 kilometres from Hong Kong, and reinject it into geological formations offshore China, but the use of CO2 for EOR at ageing oil wells is also planned.

By 2025, CNOOC intends to capture 1 million tpa of CO2 through this first scheme, but it is not clear if this figure is on a net basis, or if the estimate takes into account the increase in emissions from EOR-related output.

CNOOC’s initiative is supported by supermajors Shell and ExxonMobil under a joint study agreement, which commits the trio and local Guangdong authorities to evaluate the potential for world-scale CCS projects to reduce greenhouse gas emissions in the Daya Bay area.

The International Energy Agency recently said that CCS projects being planned worldwide will be able to capture and store 7.6 billion tonnes of CO2 by 2050.

In China, the energy industry is responsible for 73% of the country’s total CO2 emissions, which now stand at 10 billion tpa, accounting for 30% of the world’s total.

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