Question

Ocean thermal energy is due to:

• A. temperature difference at different levels in the ocean
• B. pressure difference at different levels in the ocean
• C. energy stored by waves in the ocean
• D. tides arising out in the ocean

Answer 1

The correct option is A

temperature difference at different levels in the ocean

The water at the surface of the sea or ocean is heated by the Sun while the water in deeper sections is relatively cold. This difference in temperature is exploited to obtain energy in ocean-thermal-energy conversion plants. These plants can operate if the temperature difference between the water at the surface and water at depths up to 2 km is 20 K (20°C) or more. The warm surface-water is used to boil a volatile liquid like ammonia. The vapours of the liquid are then used to run the turbine of generator. The cold water from the depth of the ocean is pumped up and condenses vapour again to liquid.