mention any two limitation in obtainig the energy from the oceans?what is OTEC?

OTEC-ocean thermal energy conversion

Ocean thermal energy conversion(OTEC) is a method for generating electricity which uses the temperature difference that exists between deep and shallow waters to run a heat engine.

The limitations obtained from oceans are --

1. Weather conditions may not be suitable all the time.

2. The initial cost of construction of the apparatus is very high.