Express News Service

CHENNAI: Chennai-based National Institute of Ocean Technology (NIOT) will soon start working to build the world’s first self-powered desalination plant using Ocean Thermal Energy Conversion (OTEC) at Kavaratti Island in Lakshadweep. NIOT officials told Express tenders have been called for and bids will be finalised in two months.

OTEC is an eco-friendly method to generate power using the difference in temperatures of the surface and the deep sea. As we go deeper and deeper in the sea, the temperature get lower. In tropical countries like India, the temperature gradient is more or less constant throughout the year, thus ensuring constant power generation potential. The process involves vaporising a low-boiling-point fluid like ammonia or water under vacuum using the surface warm sea water and condensing the vapour thus generated using deep-sea cold water. The vapour generated would drive a turbine connected to a generator, thus generating power. This cycle can be continued without breaks, and is fully renewable.

NIOT head (energy and fresh water group) Purnima Jalihal said that the Kavaratti plant, which has a capacity to produce one lakh litres of fresh portable water, will be the world’s first prototype of a OTEC-powered desalination plant and would pave the way for future large-scale plants.

“The main advantage of OTEC is that it’s completely environment friendly. NIOT had installed Low Temperature Thermal Desalination (LTTD) plants in Kavaratti in 2005 and subsequently at Agatti and Minicoy Islands. The pumps used in these plants are run using the diesel generator grid on the islands. Transportation of diesel is difficult especially during monsoon. It is also better if we adopt clean and green energy sources for the islands’ delicate ecosystem,” she said. NIOT officials also noted that there are many challenges in this project since it is being carried out for the first time ever. 

Responding to a query, Minister of State (Independent Charge) for Ministry of Science and Technology and Earth Sciences Jitendra Singh told the Parliament on Friday that NIOT is working towards installing the first-ever OTEC-powered desal plant in Lakshadweep. Also, the Geological Survey of India had mounted six cruises around Andaman and Nicobar Islands and offshore domains off AP and TN coast to find suitable sites for installation of OTEC plants.

“Based on the preliminary feasibility and assessment of the seabed and the temperature profile across the seawater column, favourable locations were identified in the offshores of Havelock Island, Little Andaman Island and Car Nicobar Island, Krishnapatnam, Andhra Pradesh and also the Puducherry coast,” the minister added.