Indian Ocean & Bay of Bengal potential CO2 sinks: IIT Madras study

Chennai: The Indian Ocean and the Bay of Bengal are potential sinks for storing large amounts of carbon dioxide (CO2), according to a study by the Indian Institute of Technology (IIT) Madras released on Monday.

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”.

Called CO2 sequestration, this process envisages the ocean acting like a storage reservoir for greenhouse gas which will help to decarbonise industrial clusters, without harming marine ecology.

The research findings can also help India achieve its national decarbonisation and climate change goals.

“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,” said Prof. Jitendra Sangwai, Department of Chemical Engineering, IIT Madras.

“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,” Prof. Jitendra added.

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.

The findings were published in several research papers in reputed peer-reviewed journals including Energy Fuels and Fuel.