Harnessing the Deep: Can Ocean-Based CCUS Be India’s Blueprint for Net-Zero? 

Ocean-based Carbon Capture, Utilisation, and Storage (CCUS) presents a strategic decarbonization pathway by leveraging the ocean’s vast capacity to store carbon, offering techniques such as sub-seabed geological storage for long-term containment, Ocean Alkalinity Enhancement (OAE) to accelerate natural CO2 absorption, and the enhancement of blue carbon ecosystems like mangroves.

For a country like India, with its extensive coastline and hard-to-abate industrial sectors, this technology offers a promising route to achieve its net-zero 2070 target by providing durable, large-scale carbon storage, fostering blue economic growth, and enabling the decarbonization of critical industries without halting development. However, the technology remains in early stages, facing significant challenges related to cost, energy requirements, and potential ecological impacts, necessitating substantial investment in research, pilot projects, and rigorous environmental impact assessments before it can be safely and effectively implemented at scale.

Harnessing the Deep: Can Ocean-Based CCUS Be India’s Blueprint for Net-Zero? 

For centuries, the ocean has been the silent, suffering partner in our climate saga, absorbing nearly a third of humanity’s carbon dioxide emissions and acidifying in the process. But what if we could shift its role from a passive sink to an active, engineered solution? This is the bold promise of Ocean-Based Carbon Capture, Utilisation, and Storage (CCUS)—a frontier technology rapidly moving from scientific papers to strategic decarbonisation pathways. For a maritime nation like India, with a vast coastline and towering climate ambitions, this isn’t just a global trend; it’s a potential blueprint for achieving net-zero by 2070 without sacrificing its developmental imperatives. 

The concept is as profound as the depths it utilises. Instead of seeing the ocean as a victim, Ocean-Based CCUS views it as the largest potential ally in our fight against climate change. The process involves capturing CO₂ from industrial point sources—think coal-fired power plants, cement factories, or steel mills—and strategically storing it not on land, but within the marine environment, either in the water column itself, deep beneath the seabed, or by enhancing the ocean’s natural carbon-sequestering abilities. 

The Technical Vanguard: How We Can Engineer the Ocean to Heal Itself 

The term “Ocean-Based CCUS” is an umbrella for a suite of innovative techniques, each with its own mechanism and promise. 

• Sub-Seabed Geological Storage: This is the most mature and direct method. Captured CO₂ is compressed into a dense, liquid-like state and transported via pipeline or ship to offshore sites. There, it is injected into geological formations deep beneath the ocean floor, such as depleted oil and gas reservoirs or saline aquifers. At depths beyond 3,000 meters, the immense pressure and low temperatures create a natural cap, often a layer of impermeable rock, trapping the CO₂ in place for millennia. This method boasts **”durable storage”**—potentially for over 100,000 years—making it one of the most permanent carbon removal solutions on the horizon. 

• Ocean Alkalinity Enhancement (OAE): This is a more nuanced approach that works with ocean chemistry. When CO₂ dissolves in seawater, it forms carbonic acid, leading to ocean acidification. OAE counters this by adding pulverised minerals (like olivine or lime) to the ocean. These substances increase the seawater’s alkalinity, which not only neutralises acidification but also enhances the ocean’s natural capacity to draw down CO₂ from the atmosphere. It’s like giving the ocean an antacid that also supercharges its carbon appetite. Electrochemical methods are also being explored to achieve this without large-scale mining. 

• Ocean Fertilisation: Perhaps the most controversial of the techniques, this involves adding limited nutrients like iron or nitrogen to nutrient-poor but otherwise fertile areas of the ocean. This “fertilisation” triggers massive blooms of phytoplankton, microscopic plants that absorb CO₂ through photosynthesis. When these plankton die, they sink, sequestering the carbon in the deep ocean. While the potential is vast, the ecological risks—including disrupting marine food webs and creating dead zones—are significant and require intense scientific scrutiny. 

• Enhancing Blue Carbon Ecosystems: While not a high-tech engineering solution, protecting and restoring coastal ecosystems like mangroves, seagrasses, and salt marshes is a powerful form of biological ocean-based carbon capture. These “blue carbon” sinks sequester carbon at rates far exceeding terrestrial forests and provide immense co-benefits for biodiversity and coastal protection. 

The Strategic Imperative: Why India Must Dive Into Ocean-Based CCUS 

The benefits of this technology portfolio align perfectly with India’s unique challenges and opportunities. 

• Vast, Untapped Storage Capacity: The most compelling argument is scale. The ocean is the planet’s largest active carbon sink, already holding 50 times more carbon than the atmosphere. For a country with an energy-hungry, industrialising economy, finding a place to put billions of tons of CO₂ is a monumental challenge. The Northern Indian Ocean and the Bay of Bengal offer a potential vast, domestic storage solution, reducing reliance on complex land acquisition and onshore geological uncertainties. 

• A Pragmatic Path for “Hard-to-Abate” Sectors: India’s core industries—cement, steel, chemicals, and fertilisers—are the backbone of its economy and also its most stubborn emission sources. They are “hard-to-abate” because their processes, not just their energy, release CO₂. Ocean-Based CCUS offers a pathway to decarbonise these sectors without forcing their shutdown, preserving economic growth and jobs while cleaning up their act. This is not about prolonging the life of fossil fuels indefinitely, but about managing the inevitable transition and dealing with legacy emissions. 

• Synergy with a Blue Economy: India’s “Sagarmala” initiative and its focus on a sustainable blue economy can be powerfully complemented by Ocean-Based CCUS. Investing in this technology can spur innovation in offshore engineering, port infrastructure, and maritime logistics. It can create high-skill jobs and position India as a leader in a nascent global industry. Furthermore, Carbon Utilisation—turning captured CO₂ into green hydrogen, biofuels, or even building materials—can foster new, sustainable domestic industries. 

• Achieving Net-Zero by 2070: The Intergovernmental Panel on Climate Change (IPCC) has made it clear that simply reducing future emissions is insufficient; we must also remove historical CO₂ from the atmosphere to meet Paris Agreement goals. Ocean-Based CCUS, particularly OAE and fertilisation, are among the few proposed methods with the gigaton-scale potential to achieve this. For India, integrating this into its long-term strategy provides a crucial hedge, ensuring it has the tools to balance its emission budget as the 2070 deadline approaches. 

Navigating the Chasm: From Promise to Reality 

Despite its promise, the path forward is fraught with challenges. The technology is in its “infancy,” and the costs are currently prohibitive without a strong carbon price or significant government subsidy. The energy required for capture, compression, and transport can be substantial, potentially creating a “parasitic” energy load. 

More critically, the environmental and governance risks are profound. Leakage from sub-seabed stores, while considered low-risk, could acidify local marine environments. Large-scale OAE or fertilisation could have unintended and widespread ecological consequences. A robust, international legal framework under conventions like the London Protocol is still evolving to govern these activities responsibly. 

The Way Forward for India: A Cautious but Determined Pilotage 

India cannot afford to be a bystander in this technological race. The government’s move to finalise a CCUS mission roadmap is a positive first step. The focus now must be on: 

• Strategic R&D Investment: Directing public and private funds towards targeted research, particularly in understanding the biogeochemical impacts of OAE in the tropical Indian Ocean context. 

• Pilot Projects and Testbeds: Following the model of the on-land CCU testbeds for the cement sector, India should initiate small-scale, meticulously monitored offshore pilot projects. Collaborations with countries like Norway, Japan, and the USA, which are already advancing in this field, are crucial. 

• Rigorous Impact Studies: Conducting detailed, transparent Environmental Impact Assessments (EIAs) and life-cycle analyses to ensure that the cure is not worse than the disease. 

• Building a Skilled Workforce: Integrating marine carbon management into the curricula of engineering and oceanography institutes to build a future-ready talent pool. 

The ocean has always been a source of life, trade, and sustenance for India. Now, it holds the potential to be a source of climate resilience. Ocean-Based CCUS is not a silver bullet, but it is a vital piece of the complex climate solution puzzle. By embracing a strategy of cautious innovation, India can navigate the depths of this new frontier, turning its blue waters into a powerful force for a secure, prosperous, and net-zero future.