Research Identifies Potential for Large-Scale CO2 Storage Using Ocean Depths
Researchers at the Indian Institute of Technology Madras (IIT Madras) have identified a promising approach for large-scale carbon dioxide (CO2) storage, utilizing the Indian Ocean and Bay of Bengal as potential repositories. This method, known as CO2 sequestration, could significantly contribute to India’s decarbonization goals.
The team’s research focuses on storing CO2 permanently in the form of solid hydrates, achieved by injecting liquid CO2 below 500 meters in depth. This technique offers a path towards carbon neutrality for industrial clusters.
“Our analysis shows that CO2 becomes denser than seawater at depths exceeding 2,800 meters,” explained Prof. Jitendra Sangwai, Department of Chemical Engineering, IIT Madras. “This added gravitational barrier further restricts CO2 escape.”
The research highlights the potential for the Bay of Bengal alone to sequester hundreds of giga tonnes of anthropogenic CO2, equivalent to several years of India’s total greenhouse gas emissions. This approach aligns with efforts in Europe, where countries like Norway and Denmark are exploring CO2 storage in the North Sea.
IIT Madras researchers emphasize the importance of safe CO2 storage. Once converted into gas hydrates, the CO2 becomes trapped beneath the ocean floor due to gravitational and permeability barriers within the sediments, preventing re-emission into the atmosphere.
The study’s key findings include:
- CO2 becomes denser than seawater at depths exceeding 2,800 meters.
- Below this depth, CO2 can be permanently stored as liquid pools and solid hydrates.
- Subsea sediments with high clay content enhance the mechanical and thermal stability of gas hydrates, promoting long-term CO2 storage.
- CO2 storage in subsea sediments offers minimal ecological impact compared to shallow-water injection.
“There are various methods for CO2 sequestration,” said Mr. Yogendra Kumar Mishra, a Research Scholar at IIT Madras. “While the ocean presents a viable storage solution, directly injecting CO2 into shallow waters can harm marine life. Our research explores permanent storage options at greater depths.”
The team’s observations suggest that hydrate formation is significantly improved by the presence of clay in seawater. Additionally, promoters like tetrahydrofuran (THF) can further accelerate hydrate formation, paving the way for large-scale CO2 storage in subsea sediments.
IIT Madras’ research offers valuable insights for optimizing CO2 storage strategies. By analyzing factors like clay concentration, additive properties, and local ocean floor characteristics, researchers can determine the most effective methods for subsea CO2 sequestration.
This breakthrough research from IIT Madras holds immense promise for India’s fight against climate change. By harnessing the potential of the Indian Ocean and Bay of Bengal for CO2 storage, India can move closer to achieving its decarbonization targets and create a more sustainable future.