The technology used for the plants is the Low Temperature Thermal Desalination (LTTD) Technology that utilizes the temperature difference available between surface water and deep sea water. In this methodology, the warmer surface sea water is evaporated at low pressures and the vapour obtained are condensed using the colder deep sea water. The cost of plant to convert sea water into drinking water would depend on the type of technology, capacity of the plant, location and cost of electricity which varies from place to place. According to the cost estimates made by an independent agency for LTTD technology, the cost per litre of desalinated potable water is about 61 paise for island based plants.
Work has been initiated to set up a prototype LTTD plant with a capacity of generating 2 million litres of potable water per day (2 MLD) at the Tuticorin Thermal Power station, Tamil Nadu by the end of XII plan period. The Lakshadweep Administration requested ESSO-NIOT for setting up similar plants in remaining six islands viz., Amini, Chetlet, Kadamath, Kalpeni, Kiltan and Andrott. ESSO-NIOT has sent a detailed project report to the Lakshadweep Administration in this regard. The proposal has not been approved so far.
This information was given by Minister of Science and Technology and Earth Sciences Dr. Harsh Vardhan in a written reply in Lok Sabha today