The Power of the Oceans
Author: Peter Young
Date Published: 2005-09-07
Tidal energy.
Thanks to our orbiting moon, twice a day the world’s oceans create
powerful water currents and the rise and fall of tides. Humans have
studied and used the tremendous power of water for over a thousand
years. 10th century millwheels harnessed the energy of rivers to grind
wheat into flour. 40 years ago, the first tidal dams were constructed,
converting the tidal energy into electricity.
Today, new energy technologies that produce power from tidal currents
could help supply as much electricity as the largest hydroelectric dam,
or nuclear / fossil fuel generating power plants without negative side
effects on our environment.
Science confers, huge advantages.
There are enormous advantages on this potential energy resource.
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The natural occurrence of the earth’s tides is a free renewable and reliable (FIRM)
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By Virtue of the physical characteristic of sea
water’s density (832 time that of air) and it’s non compressibility.
Its energy producing potential is far higher that of wind. For
example a body of water moving at 8 knots has a wind speed equivalent
of 390km/hour.
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Our environment is not damaged by greenhouse gas emissions.
Early tidal power plants.
As early as the 1930’s countries have been using tidal power with
differing success and power output levels but what is notable is that
all of these projects have stood the test of time the marine
environment and still exist.
La Rance Tidal Brige France.
In the 1960’s France began the construction of this Project. The system
consists of a 330 meter long dam across a 22 square kilometre basin
with an 8 meter tidal range. It was completed in 1967 and 24 5.5 meter
wide turbines rated at 10MW were added to the 225kV French transmission
network.
Using barrage bulb turbines, developed by Electricite de France allows this dam to generate power on both ebbs of the tide.
Marine Turbines
These could be described as underwater wind farms and have the
advantage of being much cheaper to build than tidal barrages. They also
do not have the environmental problems that a tidal barrage would bring
and there are many more suitable sites.
These underwater turbines, which are generally rated at 750 to 1500kW
per unit, (depending on the local tidal patterns and peak tidal
velocities), are grouped in arrays or "farms" below the surface.
The rotors turn slowly (about 10 – 20 RPM) so risk to marine life is
minimal as virtually all creatures which choose to swim in areas with
strong currents have excellent perceptive powers and agility.
The Future.
With the obvious effects of global warming and climate change due to
continued pumping of co2 gases into the atmosphere, marine turbines and
tidal power are an indisputably clean renewable energy resource. We
need to start now to help these alternative energies develop and for
governments to harness the power of the oceans.
Written by Peter Young
Water Well - Watering the Future
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