From 2026, Ocean Thermal Energy to provide clean water for Lakshadweep

The Ocean Thermal Energy Conversion (OTEC) plant designed and developed by the Indian Government's National Institute of Ocean Technology (NIOT) would commence operations in 2026, delivering clean energy that would help provide clean water. Situated in Kavaratti, Lakshadweep archipelago, off the Indian mainland's west coast, the OTEC plant is expected to generate up to 60 kilowatts of power from ocean water, and use that power for running a desalination plant that would provide 150,000 litres of desalinated water (seawater converted into potable water) every day. NIOT Director Prof. Balaji Ramakrishnan revealed this on the occasion of NIOT's 32nd Foundation Day.

What is OTEC technology?

In simple terms, OTEC technology is a means of generating power using the difference in temperature between ocean surface water and ocean water from the depths. In tropical climates, there is a significant difference in temperature between ocean surface water and water extracted from a 1,000-meter depth. With increasing depth, the water gets colder.

For operating an OTEC, warm water from the ocean surface is taken in to heat up a special fluid like ammonia, which boils easily. When fluid ammonia boils, it turns into a gas, which is used to spin a turbine, which is connected to a generator that produces electricity. Likewise, cold water from deep in the ocean is pumped to cool the ammonia gas, turning it back into a liquid. This perpetual heating-cooling cycle enables power generation via the OTEC. Because of the endless supply of warm surface water and cold water from the depths, this is a sustainable energy source and it can be used day and night.

Multiple desalination plants are operating in Lakshadweep; however, they are all powered by diesel generators. The OTEC is an attempt at delivering clean water from a clean energy source, Prof. Balaji told WION.

Further, as part of the Foundation Day, NOT unveiled "MANAS 1.1", an indigenously developed autonomous surface craft that is to be used for near-shore surveys. Measuring barely 4 feet in length, the battery-powered craft can be used for oceanographic surveys near the coast, thereby reducing dependence on motorised boats. Using its onboard sensors, it can measure salinity, ocean current, and carry out seabed mapping. At present, NIOT teams are testing the vessel at lakes, and it will be gradually tested in different sea conditions. The vessel is meant to operate up to 5,000 meters away from the shores, via satellite or radio frequency link, said Prof. Balaji. He added that some elements of autonomous underwater navigation technology are also being tested using "MANAS1.1".