Another type of ocean energy technology that is reaching maturity
is that referred to as Ocean Thermal Energy Conversion (OTEC),
which has significant potential for countries located in tropical regions.
These plants must be located in an environment where the
warm surface seawater must differ about 20 C from the cold deep
water that is no more than about 1000 m below the surface, and
the shore must be located within 25 km of the ocean region where
the temperature difference occurs. This is normally found in areas
between latitudes 20 North and South of the Equator, as shown in
Fig.