Context: The National Institute of Ocean Technology, an autonomous institute under the Union Ministry of Earth Sciences (MoES) is establishing an Ocean Thermal Energy Conversion(OTEC) plant with a capacity of 65 kilowatts (kW) in Kavaratti, the capital of Lakshadweep.

• The plant is the first of its kind in the world as it will generate drinking water from seawater using indigenous technology, green energy and environmentally friendly processes.

Ocean Thermal Energy Conversion(OTEC)

• Ocean thermal energy conversion(OTEC) is a process or technology for producing energy by harnessing the temperature differences (thermal gradients) between ocean surface waters and deep ocean waters. 

• Especially in tropical regions, surface water can be much warmer than deep water because of the Sun’s heat. 

• This temperature difference can be used to produce electricity and desalinate ocean water.

• Note: OTEC systems use a temperature difference (of at least 77°F) to power a turbine to produce electricity.

Its working

• Warm surface water is pumped through an evaporator containing a working fluid. The vaporized fluid drives a turbine/generator.

• Then the vaporized fluid is turned back to a liquid in a condenser cooled with cold ocean water pumped from deeper into the ocean.

• OTEC systems use seawater as the working fluid and can use condensed water to produce desalinated water.

Advantages of OTEC: Two of the biggest advantages of OTEC are: 

• It produces clean environmentally friendly renewable energy and 

• Unlike solar plants which can’t work at night and wind turbines which only work when it’s windy, OTEC can produce energy at all times.

Disadvantages of OTEC: The disadvantages are that 

• It is economically expensive and

• It only works in a few regions of the world as the required temperature difference is only present in tropical waters.