Wave energy is efficient and plentiful
Wave energy is a clean, renewable source of energy, caused by wind blowing over the surface of the ocean. Wind is created by the sun's solar energy. Waves gather, store, and transmit this energy thousands of miles with little loss. As long as the sun shines, wave energy will never be depleted. It varies in intensity, but it is available twenty-four hours a day, 365 days a year. The total power of waves breaking around the world’s coastlines is estimated at 2-3 million megawatts. The west coast of the U.S. and Europe and the coasts of Japan and New Zealand are good sites for harnessing wave energy. Other forms of wave energy have slightly different names and technologies to harness their power: wave power, tidal power and tidal energy.
How is wave energy harnessed?
There are three basic technologies for changing wave energy to electric power:
1.) Float or buoy systems that use the rise and fall of ocean waves to power hydraulic pumps. The structures can be mounted to a floating raft or to a device drilled into the ocean floor. A series of anchored buoys rise and fall with the waves. This relative motion drives electromechanical or hydraulic energy converters. Electricity reaches shore via underwater cables.
2.) Oscillating water columns in which the in-and-out motion of waves at the shore enters a column and forces air to turn a turbine. Water enters through a subsurface opening into a chamber with air trapped above it. The wave action causes the captured water column to move up and down like a piston and turn a turbine. That energy is then harnessed and sent to shore by electrical cable.
3.) “Tapered channel” or “tapchan” systems use structures fixed at the shoreline to channel and concentrate waves, directing them into an elevated reservoir. Water flow out of this reservoir powers a generator, which produces electricity.
Where are the best waves?
Wave power varies widely in different parts of the world. Areas of the world where the power of the waves are very strong include the western coasts of Scotland, northern Canada, southern Africa, Australia and the northwestern coast of the United States.
What is the impact on the environment?
Unlike dams, wave-powered structures have few harmful environmental effects. Wave power is renewable, green, pollution-free, and environmentally invisible. Its net potential (resource minus “costs”) is equal to or better than wind, solar, small hydro or biomass power.
What are some advantages of ocean wave energy?
Because waves originate from storms far out to sea and can travel long distances without significant energy loss, power produced from them is much steadier and more predictable, both day-to-day and season-to-season.
Wave energy contains roughly 1000 times the kinetic energy of wind, allowing much smaller and less conspicuous devices to produce the same amount of power in a fraction of the space.
Unlike wind and solar power, power from ocean waves continues to be produced around the clock, wind velocity tends to die in the morning and at night, and solar is only available during the day in areas with relatively little cloud cover.
Because wave energy needs only 1/200 the land area of wind and requires no access roads, infrastructure costs are less.
Wave energy devices are quieter and much less visually obtrusive than wind devices, which typically run 130-200 feet in height and usually require remote siting with attendant high transmission costs. In contrast, 30-foot high wave energy devices can be integrated into breakwaters in busy port areas, producing power exactly where it is needed.
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