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 currently a widely employed commercial technology although there have been attempts at using it since at least 1890.The world's first commercial wave farm is based in Portugal, at the Aguçadora Wave Park, which consists of three 750 kilowatt Pelamis devices.
Oceans cover almost three-fourths of the earth’s surface. The oceans' waters, the air above the oceans, and the land beneath them contain enormous energy resources. These energy resources include non-renewable energy sources such as oil and gas, and renewable energy sources, such as offshore wind energy, wave energy, ocean current energy, offshore solar energy. Offshore renewable resources are the focus of the OCS Alternative Energy Programmatic EIS.
Physical concepts
Waves are generated by wind passing over the sea: 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. Both air pressure differences between the upwind and the lee side of a wave crest, as well as friction on the water surface by the wind shear stress cause the growth of the waves.The wave height increases with increases in (see Ocean surface wave):
wind speed,
time duration of the wind blowing,
fetch — the distance of open water that the wind has blown over, and
water depth (in case of shallow water effects, for water depths less than half the wavelength).…
