News Desk
NEW DELHI — India is advancing a homegrown desalination technology that could provide a lifeline for water-scarce nations across the Global South. The country’s low-temperature thermal desalination (LTTD) system, developed by the National Institute of Ocean Technology (NIOT), leverages the natural temperature gradient between warm surface seawater and cold deep-sea water to produce fresh, potable water.
Unlike energy-intensive reverse osmosis (RO) plants, LTTD operates with minimal power requirements and a lower environmental footprint. It has already transformed water access in India’s island territories, and now, officials are positioning the technology for broader adoption in Indo-Pacific nations and small island developing states (SIDS).
India’s first LTTD plant was commissioned in 2005 in Kavaratti, Lakshadweep, supplying 100,000 liters of drinking water per day at a cost of ₹50 million ($922,000). Since then, NIOT has expanded operations to Amini and Kalpeni islands, where plants inaugurated in 2023 now produce 150,000 liters per day. A floating offshore plant off Chennai further demonstrated scalability.
The principle is straightforward: warm surface water, typically around 28°C, is evaporated at low pressure, and the vapor is condensed using deep-sea water at 12-15°C, yielding fresh water. The process consumes significantly less power than conventional desalination—around 1-2 kWh per cubic meter, compared to 3-4 kWh for RO.
With climate change worsening water scarcity, LTTD presents an affordable, sustainable alternative for many coastal and island nations. Countries like the Maldives, Seychelles, and Pacific island nations have the right oceanic conditions for deployment. Experts also see potential in African coastal states, where desalination is often prohibitively expensive due to high energy costs.
Dr. G.A. Ramadass, Director of NIOT, highlighted LTTD’s strategic advantage: “This is a sustainable solution for water-stressed regions that struggle with energy access. By integrating renewable power, we can make LTTD entirely emission-free.”
India’s push to market LTTD aligns with its broader diplomatic outreach in the Indo-Pacific. Under initiatives like the Forum for India-Pacific Islands Cooperation (FIPIC), New Delhi has promoted the technology as a low-cost, sustainable alternative to imported desalination systems. Industry experts estimate that with scaling, production costs could fall to ₹30-60 ($0.36-$0.72) per cubic meter, making LTTD competitive with traditional methods.
Beyond technology exports, India sees LTTD as a tool for strengthening regional ties. “Water security is a critical issue in the Global South, and India is uniquely positioned to offer a viable, eco-friendly solution,” said a senior official in the Ministry of Earth Sciences.
While LTTD has proven effective, it has limitations. Its water recovery rate, around 10% compared to RO’s 50-60%, means larger volumes of seawater are needed. But for nations with abundant coastlines, the trade-off in energy efficiency and maintenance costs makes it attractive.
NIOT is now working on scaling up LTTD for high-capacity offshore installations, with a 10,000 m³/day plant planned off the Chennai coast. If successful, it could pave the way for commercial adoption in Africa, Latin America, and island nations struggling with freshwater shortages.
With a growing global focus on sustainability, India’s LTTD innovation is poised to reshape desalination strategies worldwide. As water scarcity intensifies, this homegrown technology may emerge as a game-changer for the Global South.
