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Tides are generated
through a combination of forces exerted by the
gravitational pull of the sun and the moon and the
rotation of the earth. The relative motion of the
three bodies produces different tidal cycles which
affect the range of the tides. In addition, the
tidal range is increased substantially by local
effects such as shelving, funnelling, reflection
and resonance.
Energy can be extracted from tides by creating a
reservoir or basin behind a barrage and then
passing tidal waters through turbines in the
barrage to generate electricity. Tidal energy is
extremely site specific requires mean tidal
differences greater than 4 metres and also
favourable topographical conditions, such as
estuaries or certain types of bays in order to
bring down costs of dams etc.
Since India is surrounded by sea on three sides,
its potential to hamess tidal energy has been
recognised by the Government of India. Potential
sites for tidal power development have already
been located. The most attractive locations are
the Gulf of Cambay and the Culf of Kachchh on the
west coast where the maximum tidal range is 11 m
and 8 m with average tidal range of 6.77 m and
5.23 m respectively. The Ganges Delta in the
Sunderbans in West Bengal also has good locations
for small scale tidal power development. The
maximum tidal range in Sunderbans is approximately
5 m with an average tidal range of 2.97 m. The
identified economic tidal power potential in India
is of the order of 8000-9000 MW with about 7000 MW
in the Gulf of Cambay about 1200 MW in the Gulf of
Kachchh and less than 100 MW in Sundarbans. The
Kachchh Tidal Power Project with an installed
capacity of about 900 MW is estimated to cost
about Rs. 1460/- crore generating lectricity at
about 90 paise per unit. The techno-economic
feasibility report is now being examined. |
