(From Turquoise Energy News #59, Dec
2012 - slightly revised here.)
Simple! Ocean
Wave Power Device
A friend sent me a link to a web/PDF book on free energy
devices: http://www.free-energy-info.co.uk/
. After Christmas I had a brief look. It has a wide variety of
interesting devices
including magnetic and coil energy machines, but one that struck me
almost instantly was
a simple device for extracting ocean wave power:
At a glance the diagram looks "Mickey Mouse" - a toy for a
theoretical demo perhaps. But the simplicity is pure genius! Each
feature is
the essence of the matter boiled down to the simplest and most
effective form.
First and foremost, a lightweight buoy with a concrete
anchor, pulley and rope are
the only pieces in
the corrosive salt water environment. (The pulleys would be on swivels
at both ends of course.) Simple, robust parts can more easily be
designed
to withstand storms than more complex things. A foam filled float that
will submerge without lifting its anchor is little subject to damage
by surging waves. The rest of the structure is on solid ground - and
thus isn't rocking adversely in the same waves the power capture floats
are in. This makes for the best leverage on the waves.
Next, something has to
run from the device in the water to shore, and rope is cheap
compared to heavy electrical cable, especially that made for sub-sea
use.
Thus floats can be placed in deeper water farther from shore without
much extra cost. Waves have more power in deeper water before they
incur bottom friction in the shallows. And they're 'more solid' in the
deep before they
start to break.
Third, forget the hole in the ground: the shore
installation would be an enclosed tower. (at least a tall
pole is
needed for the high voltage lines leading away anyway.) The weights
would have a
long range over which they could rise and fall from the overhead drive
shaft to the ground, so tides would be no problem. In fact, differing
tide levels will even out the back and forth rope/pulley wear over
sections of rope. The ropes will be well overhead.
Finally, the entire system needs just one large generator
and one-way "transmission" that ties
it to all the floats. Instead of a unit associated with each float,
there's just one large mechanism to be mounted, wired and
maintained. This is a huge economy. (Note: The 'ratchet drives' shaft
will have to be
considerably geared up to turn a generator at speeds it'll make power
at. It might well take a two-stage increase. Here again the nearly 99%
efficient flat belt drive of tough modern materials would doubtless
make the
best speed converter with the least friction - and little noise.)
Naturally one would employ a set of floats offset
diagonally from each other and at different distances out to sea,
spanning at least a typical wave length, so that the drive shaft is
being continually driven as the wave passes each float in turn. A
flywheel could help smooth
out
bumps. The maximum power harnessed depends on the volume of the
flotation and the weight of the hanging weights. One person says
sizing the components to resonate with the typical wave frequency will
increase power gained. (I'm somewhat skeptical that the effect will be
pronounced owing to the damping caused by extracting the power, but
even a few percent improvement is an improvement.) My own improvement
idea would be what I've proposed before: longer, thinner, shallower
floats - oval shaped pipes perhaps - that would line up with the waves
to
optimally catch the topmost crests of the most linear meters of
wavefront. (Think of the buoy in
the diagram as being the cross section of a piece of pipe maybe 3 or 4
times as long as the width.)
Any system has its disadvantages as well as advantages.
Ropes would be going back and forth well overhead across the
beach instead of having buried electrical cables, and the tall base
structure wouldn't be intrinsically attractive except in the eyes of
the builders. But most any wave power system is going
to have some basic similarities -
floating components to transfer the power of the waves to a mechanical
or hydraulic system, some sort of shore installation, and power lines
heading for the grid somewhere.
I would think such simple installations could be created
for a
small fraction of the cost of either hydro dams or wind power, and
could indeed satisfy the bulk of our energy needs here
on Vancouver Island. One could build a "Site C Dam" equivalent as
affordable small projects over some years - perhaps for around 3
billion dollars instead of 10. A test installation should surely be
tried out.
I'm not favorably situated to attempt the experiment.
Craig Carmichael
www.TurquoiseEnergy.com
Victoria BC