|
OTEC utilizes the temperature
different between warm (26 C) surface waters of
low latitude tropical oceans and the cool deep
waters (5-10 C) lying below a depth of a few
hundred meters to run a turbine and a generator
via a heat exchanger and a suitable medium (e.g.
ammonia or low pressure steam). OTEC is a method
of using solar energy stored as a temperature
difference in the oceans.
The earth’s oceans absorb solar radiation the
major part of which they store as thermal energy
in the warm surface waters. On the other hand,
cold water layers move slowly from polar regions
towards the equator at depths of less than 100 m.
Thus, a vertical temperature difference of up to
25 C exists throughout the year at many tropical
locations According to the fundamental laws of
thermodynamics, this temperature gradient can be
exploited as an energy source. The ocean thermal
gradient does not vary significantly from day to
night and hence can be regarded as a steady source
of energy. It does have however, a seasonal
variation which increases with the distance from
the equator.
The natural power potential of the thermal
gradient energy is estimated to be as large as 10
W (10 TW). Obviously it is not technically
feasible to extract all this energy. A fair
estimation would be approximately 10 W as against
the world installed electrical generation capacity
of the order of 10 W.
In India activities in this area are coordinated
by the OTEC Cell at Indian Institute of
Technology, Madras. A feasibility study of setting
up a 5 to 8 MW pilot R & D OTEC plant off the main
Anandman Islands is ready and a proposal for a
feasibility study for installation of a 100 MW
OTEC plant off Madras is under consideration. |
