Indian Ocean and Bay of Bengal serve as potential CO2 sinks: IIT Madras

Chennai: Indian Institute of Technology Madras’ researchers have revealed the Indian Ocean and Bay of Bengal as potential storage sinks for storing large amounts of carbon dioxide (CO2) that decarbonize Industrial Clusters.

The researchers found that CO2 can be stored permanently in the ocean in the form of solid hydrate beyond 500 m of sea depth through the liquid CO2, thereby can be helpful to make our industrial clusters carbon neutral.

The key findings of this research is that it can help devise large-scale CO2 storage and utilize the fullest potential of oceans to decarbonize the world without harming marine ecology. This research can also help India achieve its National decarbonisation and climate change goals.

The stored carbon dioxide can create an eco-friendly ice-like substance called ‘Gas Hydrates’. One cubic meter of gas hydrate can sequester approximately 150-170 cubic meters of CO2 under oceanic conditions beyond 500 meters.

Thus, gas hydrates-based storage has huge potential to decarbonize India’s industrial clusters. This research will pave pathways to develop large-scale sequestration in subsea sediments that help the scientific community to fulfill India’s net-zero targets.

Called ‘CO2 sequestration,’ this process envisages the ocean acting like a storage reservoir for greenhouse gas which will help to decarbonize industrial clusters.

The research was led by Prof. Jitendra Sangwai, Department of Chemical Engineering, IIT Madras, and Mr. Yogendra Kumar Mishra, Research Scholar (Prime Ministers Research Fellow), IIT Madras.

Highlighting the importance of this research to India, Prof. Jitendra Sangwai, Department of Chemical Engineering, IIT Madras, said, “Methane hydrates have been in the ocean for millions of years without affecting the environment. Methane is a more potent greenhouse gas than CO2. This attracts researchers to explore the ocean to store CO2 permanently. Our analysis shows that at above 2,800 m depth, CO2 is denser than seawater, which offers an additional gravitation barrier for CO2 to escape.”

Prof. Jitendra Sangwai added, “Our dependence on fossil fuels will continue for the foreseeable future till we find a reliable source of energy to completely replace fossil fuels. Thus, CO2 capture and sequestration is a very important precursor to achieving net-zero goal”

“Once CO2 is captured from the source, it needs to be sequestered safely. CO2 sequestration in oceans will be beneficial for India as, according to a conservative estimate, the Bay of Bengal alone can be able to sequestrate several hundred giga tonnes of anthropogenic CO2 in oceans and marine sediments, which is equivalent to several years of total GHG (Greenhouse Gas) emission emitted by India. Some countries in Europe (e.g., Norway and Denmark) are working on CO2 storage in the North Sea” he explained.

Once the CO2 is permanently stored as a gas hydrate, it does not allow for any reemission into the atmosphere owing to the gravitational and hydrate permeability barrier in the subsea sediments.