12/04/08
WAVES~~~
Waves are created by the progressive transfer of energy from wind currents passing over the surface of the ocean (as long as the waves propagate slower than the wind speed just above the waves, there is an energy transfer from the wind to the most energetic waves). Waves are formed from turbulence because wind pressure pushes down wave troughs and lifts up wave crests, due to Bernoulli's principle. (will be elaborated in physics principles)
Generally, large waves are more powerful. Specifically, wave power is determined by wave height, wave speed, wavelength, and water density.
The equation here:
View: http://en.wikipedia.org/wiki/Wave_energy#Physical_concepts
where,
P the wave energy flux per unit wave crest length (kW/m),
Hm0 is the significant wave height (meter), as measured by wave buoys and predicted by wave forecast models. By definition, Hm0 is four times the standard deviation of the water surface elevation,
T is the wave period (second),
ρ is the mass density of the water (kg/m3), and
g is the acceleration by gravity (m/s2)
shows the factors affecting the size and power of a wave.
It also states that wave power is proportional to the wave period and to the square of the wave height. When the significant wave height is given in meter, and the wave period in second, the result is the wave power in kW (kilo watt) per meter wavefront length.
--yingshi
22/04/08
WAVES AS A SOURCE OF ENERGY
Renewable energy effectively uses natural resources such as sunlight, wind, rain, tides and geothermal heat, which are naturally replenished. Renewable energy technologies range from solar power, wind power, hydroelectricity/micro hydro, biomass and biofuels for transportation. Therefore, wave energy does have its benefits of being renewable and environmentally friendly. (This is elaborated further below)
Wave power refers to the energy of ocean surface waves and the capture of that energy to do useful work - including electricity generation, desalination, and the pumping of water (into reservoirs). Wave power is a form of renewable energy. Though often co-mingled, wave power is distinct from the diurnal flux of tidal power and the steady gyre of ocean currents. Wave power generation is not a widely employed technology, and no commercial wave farm has yet been established.
The movement of waves and the rising and falling of tides can be harnessed to drive turbines that generate electricity. There are two main types of wave energy collectors. The first type directs waves into man-made channels, where the water passes through a turbine that generates electricity. The second type uses the up and down movement of a wave to push air.
Wave is a powerful source of energy. In fact, it can go up to many metres in height. The total power of waves breaking around the world’s coastlines is estimated to be 2 to 3 million megawatts.
Wave power varies considerably in different parts of the world, and wave energy cannot be harnessed effectively everywhere. Wave-power rich areas of the world include the western coasts of Scotland, northern Canada, southern Africa, Australia, as well as the northwestern coasts of United States.
Good wave power locations have a flux of about 50 kilowatts per metre of shoreline. Capturing 20 percent of this, or 10 kilowatts per metre, is plausible. Assuming very large scale deployment of (and investment in) wave power technology, coverage of 5000 kilometres of shoreline (worldwide) is plausible. Therefore, the potential for shoreline-based wave power is about 50 gigawatts. Deep water wave power resources are truly enormous, but perhaps impractical to capture.
--cassandra
--
08/05/08
BENEFITS OF WAVE ENERGY (brief overview)-- Renewable and environmentally friendly
Wave energy is a renewable and pollution-free energy source that has the potential to contribute with 2,000 TWh per year of the world's energy production.
Wave energy is free. No fuel is needed to generate the energy and thus no waste is produced. Wave energy plays a major role in the world's efforts to prevent climate change. It potentially displaces 1 to 2 billion tonnes of CO2 annually from usual fossil fuel generating sources.
--yingshi
Entire post reviewed and edited by same people who wrote it:
07/06/08
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