| Harnessing the vast power of the oceans' waves has | | | | takes advantage of vertical motion is called an |
| recently gained popularity as a form of renewable | | | | attenuator, also known as surface-following |
| energy that does not contribute to global warming. | | | | technology. Pelamis devices have cornered this |
| Seventy percent of the world's electricity needs are | | | | section of the market, and virtually no other |
| met by burning fossil fuels such as coal or natural | | | | technologies are available. These generators derive |
| gas, and these methods generate vast quantities of | | | | their name from Pelamis platuris, a yellow-bellied sea |
| greenhouse gasses. Hydropower has long been | | | | snake, a fitting name considering the generator's long, |
| considered a renewable alternative, but the current | | | | narrow design, and its oscillating movements. The |
| technique for harnessing that power, namely | | | | machine consists of long, buoyant tubes connected |
| damming rivers, can be extremely damaging to | | | | by two arms at movable joints. As the waves |
| ecosystems, and nearly all of the suitable locations in | | | | change the angle of two tubes with respect to each |
| the world have already been tapped. Now scientists | | | | other, hydraulic pumps are compressed and |
| and engineers are learning to harness the unending | | | | stretched, driving hydraulic generators. These Pelamis |
| power of ocean waves, promising electricity | | | | generators are being used in the world's first |
| generation with minimal environmental effects. None | | | | commercial wave farm, the Aguçadora Wave |
| of the current wave power technologies create | | | | Park off Portugal, and also in the 3MW wave farm |
| greenhouse gasses or pollution. | | | | off the coast of Scotland. |
| Many different technologies have been developed to | | | | The remaining wave-harnessing technologies, referred |
| convert waves into electricity. Two of the most | | | | to as terminators, take advantage of the horizontal |
| promising technologies take advantage of the vertical | | | | motion of waves. The oscillating water column design |
| motion of waves. The first of these is a buoy or | | | | uses the motion of a wave-driven piston to drive |
| point-absorber generator. These designs contain a | | | | pressurized air through a turbine, which in turn drives |
| fixed component and a floating component. Waves | | | | a generator. Overtopping is suggested for use either |
| move the floating component up and down in relation | | | | on or offshore, and involves funneling wave water |
| to the fixed component, driving one of several types | | | | into elevated reservoirs. Gravity then pulls water |
| of systems. An arm protruding from the buoy can be | | | | back downward, where it is funneled to drive a |
| attached to a crank, which then turns a mechanical | | | | turbine, much as in hydropower dams. The most |
| generator. Similarly, self-contained hydraulic pumps | | | | famous of this type is the Wave Dragon off the |
| can be driven by the motion of the buoy, then | | | | coast of Denmark. The Wave Dragon includes two |
| driving a hydraulic motor. Yet another system uses | | | | arms that funnel and amplify the waves before |
| the motion to pump pressurized sea water. This | | | | driving the water into the reservoir. Two very |
| pressurized sea water can then be pumped through a | | | | innovative designs, the Oyster and the Neptune, |
| turbine or even pumped onshore to drive osmotic | | | | have been developed by Aquamarine Power. The |
| desalination processes. Buoy generators are currently | | | | oyster is a large plate mounted to the sea floor, |
| being used in several locations. Finavera has projects | | | | whose back-and-forth motion is resisted by hydraulic |
| in waters off Portugal, Africa, and the North Pacific | | | | arms which run a hydraulic generator. The Neptune |
| waters of the US and Canada. Oregon State | | | | uses underwater, bi-directional turbines to harness |
| University has a pilot project off the coast of | | | | tidal energy. |
| Reedsport, and CETO, has a project running off | | | | To learn more about different alternative energy |
| Western Australia. The second type of design that | | | | solutions, visit the alternative energy weblog. |