Ocean Thermal Energy Conversion:
The National Institute of Ocean Technology, an autonomous institute under the Union Ministry of Earth Sciences (MoES) is establishing an Ocean Thermal Energy Conversion Plant with a capacity of 65 kilowatts (kW) in Kavaratti, Lakshadweep.
- The plant will power the one lakh liter per day low temperature thermal desalination plant, which converts seawater into potable water.
- The plant is the first of its kind in the world as it will generate drinking water from sea water using indigenous technology, green energy and environmentally friendly processes.
- Ocean Thermal Energy Conversion (OTEC) is a process for producing energy by harnessing the temperature differences (thermal gradients) between ocean surface waters and deep ocean waters.
- Oceans are huge heat reservoirs as they cover almost 70% of Earth’s surface.
- Researchers focus on two types of OTEC technologies-
- Closed cycle method – where a working fluid (ammonia) is pumped through a heat exchanger for evaporation and the steam runs a turbine.
- The vapour is turned back to fluid (condensation) by the cold water found at the depths of the ocean where it returns to the heat exchanger.
- Open cycle method – where the warm surface water is pressurized in a vacuum chamber and converted to steam which runs the turbine. The steam is then condensed using cold ocean water from lower depths.
- India initially had planned to set up an OTEC plant way back in 1980, off the Tamil Nadu coast. However, with the foreign vendor closing down its operation, it had to be abandoned.
- India’s OTEC Potential:
- As India is geographically well-placed to generate ocean thermal energy, with around 2000 kms of coast length along the South Indian coast, where a temperature difference of above 20°C is available throughout the year.
- The total OTEC potential around India is estimated as 180,000 MW, considering 40% of gross power for parasitic losses.