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W a v e s & W h i s t l e s
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Fossil fuels such as coal and oil are not renewable over the span of
human generations, and their use may be increasingly limited by
environmental concerns over global warming and acid rain. To meet the
energy needs of a growing world population, engineers in coming
decades will be challenged to economically generate power from solar
energy sources.
Ocean waves are a tertiary form of solar energy, in that unequal
heating of the Earth’s surface generates wind, and wind blowing over
water generates waves. Despite the fact that nearly 75% of the Earth’s
surface is covered with water, waves are a largely unexplored source
of energy, compared with the progress that has been made in harnessing
the sun and wind.
Until
recently the commercial use of wave power has been limited to small
systems of tens to hundreds of watts aboard generate power . As the
buoy heaves up and down in waves, the oscillating water column (OWC)
in the centre pipe of the buoy's hull acts like a piston, alternately
pushing air out the top of the pipe and drawing it in. This pneumatic
power can be converted directly to sound through a foghorn, or
indirectly to light by spinning a turbine-generator, which charges an
electrical storage battery (Figure 1)
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Ocean wave
energy conversion for utility scale power generation is now becoming a
commercial technology. A 75 kW shore-based demonstration plant by
Queens University, Belfast, using the OWC process described above has
operated on the Scottish island of Islay for 10 years (Figure 2).
The output
of this plant has allowed significant research and technical
development to take place.
To go onto
the 2nd of 5 pages click on
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Objectives
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