Wave Power

Wave Power the perpetual energy source

What is ocean wave power?

Wave power is the energy from the sun transformed into wind that blows across the surface of the ocean. Waves gather, store, and convey this energy thousands of miles with little loss. Wave energy is constantly available although it varies in intensity. Renewable energy experts believe there is enough energy in the ocean waves to provide up to two trillion watts of electricity.

Where are the best waves found?

Wave power can’t be harnessed everywhere. Some of the best places in the world to harness wave energy are southern Africa, Australia, northern Canada, and the northeastern and northwestern coasts of the United States.

Wave power technologies

There are offshore and onshore systems which can tap the ocean’s wave energy.

Offshore systems are located more than 130 feet deep. Some of these systems use hoses connected to floats that bounce on the waves. The up and down motion of the float stretches and relaxes the hose, which pressurizes the water, which turns a turbine. The Slater Duck uses the bobbing motion of the waves to run a pump that generates electricity. Floating platforms that funnel waves through internal turbines and discharge the water back into the ocean can also create electricity.

Onshore systems harness the energy in breaking waves; they are built near the shoreline.

Pendulor devices are made up of a rectangular box, which is open to the ocean on one side. A flap is hinged over the opening and wave motion causes the flap to swing back and forth. The motion powers a hydraulic pump and a generator.

Oscillating water columns are made up of partly submerged concrete or steel structures that have an aperture to the ocean below the waterline. It encloses a pillar of air above a pillar of water. As the waves enter the air pillar, they cause the water pillar to go up and down. This alternately compresses and depressurizes the air pillar. As the wave retreats, the air is drawn back through the turbine because of reduced air pressure on the ocean side of the turbine.

Tapchan or tapered channel systems are a tapered channel, which corrals waves into a reservoir built on cliffs above sea level. The tapering of the channel make the waves grow taller as they move toward the cliff face. The waves topple over the walls of the channel into the reservoir and this collected water is then used to power a turbine.

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Source:  US Department of Energy - Wave Power