“Things you know that ain't so - wave power will soon provide substantial low-cost generation.” The first wave power machine was made in the early 1900s. It was mechanically complex and was a commercial and technical failure.
With
the OPEC oil crisis in the 1970s, there was a resurgence of interest in wave
power. The most notable of the of the prototypes was “Salter's Duck” that had a
number of segments shaped floats rotating central axis. In theory, it looked
really good. But Prof Norman Bellamy, who built a prototype and tested it,
reported that the mechanical complexity was greater than expected and the power
output was about one third of expected. He went on to develop a new device
consisting of floating hinged steel tubes that faced into the waves and
generated electricity from hydraulic rams at each hinge as the wave passed
along the device. Prototype tests on Loch Ness revealed serious problems with
designing and manufacturing a device that could withstand a storm and still
generate useful amounts of power under normal wave conditions. So he abandoned
that option and switched to a system with air bags that was much more
promising. A prototype was built and was quite promising that he eventually
abandoned it to pursue more attractive options.
When
the global warming scare convinced many governments that renewable energy might
be a way of solving the carbon dioxide problem, lots of money was made
available for wave power development. One organisation revived Bellamy's hinged
steel tube concept and spent millions of dollars trying to make it work. They
went into administration a few months ago. Another organisation carried out
further development on Prof Bellamy's airbag system but, it seems, without any
prospect of generating electricity at a cost anywhere near conventional
generation.
A
New Zealand organisation has developed yet another device that is more robust
than most and may well have a use providing small amounts of electricity for
offshore installations and, possibly, small communities where diesel power is
seriously expensive. But, as with the other prototypes the tonnage of steel required
per kilowatt of output is simply far too great.
Over
the last few years Prof Bellamy has developed an entirely new concept based on
a rubber tube with an internal diaphragm. It is moored head onto the waves and
as a wave passes along it pumps air at a steadily increasing pressure from one
end to the other. The compressed air is then piped to shore where it drives an
air turbine generator. This system has a huge advantage that much of the
expensive equipment is onshore and if the tube is lost in a storm, it is
relatively cheap and easy to replace it. If the remaining technical and
economic problems can be overcome, it could be producing commercial power in 5
-10 years time.
As
with solar, wind and tidal power, it will need to feed power into a large system
that can cope with the fluctuations in output or it will need substantial and
very expensive energy storage systems.
The
conclusion is that all but one of the systems now under development have severe
mechanical and economic problems. If Prof Bellamy’s system is successful, all
the other systems will be obsolete overnight.
The
chances that wave power will produce a substantial amount of low-cost power in
the foreseeable future are extremely small because, almost certainly, nuclear
power and fossil fuels can provide a continuous supply of electricity at an
equivalent or lower cost. (As the world has not warmed for the last 18 years,
we can be confident that man-made carbon dioxide does not cause dangerous
global warming.)
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