For some time there has been interest in developing technology to generate electricity from the power inherent in ocean waves. It is actually wind or solar energy in a different form, given the fact that solar heat induces storm winds that create irregular complex waves. These die down to produce relatively smooth waves that retain much of the energy of the original storm waves. Certain coastlines, notably offshore Oregon, Washington, California and Rhode Island, as well as Portugal, Australia and elsewhere have been considered good locations to conduct experiments to determine whether wave energy can be usefully converted to electricity at an acceptable cost.
Ocean Power Technologies, a New Jersey company, is about to start up, offshore Oregon, a commercially licensed grid-connected wave energy device. If results are promising, up to ten generators will be installed to power about 1000 homes.
Several types of devices have been proposed to capture the wave energy. So- called terminator devices are columns with trapped air where a water column fed by the wave compresses the air and forces it into a turbine. A unit of this type was installed in Australia and evaluated by the Electric Power Research Institute. Variations of this approach use magnets and electric coils.
Attentuators are long, multisegment floating structures where waves cause flexing of the segments that is reflected by hydraulic pumps. A different form of this has pontoons that move up and down with a hydraulic fluid that drives a motor generator.
Then, there are conceptual ”Overtopping” devices, which have reservoirs that are filled by impinging waves to levels above the normal ocean level. The reservoir then releases the water by letting it flow through a turbine.
It has been estimated that with time and experience, some of these approaches could generate power at 10-12 cents/kwh. This would be commercially attractive in some parts of the world, though doubtful for the U.S., except for specialized locations There are also environmental issues such as unsightliness and interference with fishing and marine life. However, these are probably not insurmountable.
Alternative energy sources (not including nuclear) are now responsible for over ten percent of total US power generation. However, hydroelectric power accounts for most of this. With cheap natural gas likely to be available for a long time, it will be difficult for solar, wind, and now wave energy to make much of a dent in the total picture. In Europe and Asia it’s a somewhat differeent story.
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