Wave power, a form of renewable energy in which electricity is generated by harnessing the up-and-down motion of ocean waves. Wave power is typically produced by floating turbine platforms or buoys that rise and fall with the swells. However, wave power can be generated by exploiting the changes in air pressure occurring in wave capture chambers that face the sea or changes in wave pressure on the ocean floor. For instance, the world’s first operational wave power generator is located off the coast of Aguçadora, Portugal, producing as much as 2.25 megawatts from three huge jointed tubes that float on the surface of the Atlantic Ocean; individual power generators are located at the tubes’ joints and activated by wave motion. In addition, a large potential for wave power systems exists in the British Isles and the Pacific Northwest of the United States. Estimates of the annual wave energy potential along the continental shelf of the U.S. coasts range between 1,170 and 2,640 terrawatt-hours, equivalent to 33–65 percent of U.S. electricity demand in 2015.
Wave energy technology
Several different wave energy technologies currently exist. They are designed to harness wave energy in different environments.
A point absorber is a floating buoy that absorbs energy through the movement of the waves at the water’s surface.
An oscillating wave surge converter is mounted on the seabed in shallower water, and harnesses wave energy with an oscillating flap.
An oscillating water column is a partially submerged, hollow structure which is open to the sea water below the surface and connects to an air turbine above through a chamber. As the waves rise and fall, the air in the chamber is pushed back and forth through the air turbine, generating power.
Wave Power
Wave power is the capture of energy of wind waves to do useful work for example, electricity generation, water desalination, or pumping water. A machine that exploits wave power is a wave energy converter (WEC). Waves are generated primarily by wind passing over the sea's surface and also by tidal forces, temperature variations, and other factors. As long as the waves propagate slower than the wind speed just above, energy is transferred from the wind to the waves. Air pressure differences between the windward and leeward sides of a wave crest and surface friction from the wind cause shear stress and wave growth
The world's largest untapped source of energy
With a staggering global resource, wave energy has the potential to be the largest source of energy from our seas. The Intergovernmental Panel on Climate Change (IPCC) puts the potential annual global production at 29,500 TWh. This is almost ten times Europe’s annual electricity consumption of 3,000 TWh.
Wave energy can provide utility-scale power production, and works very well in tandem with other renewables such as wind. It is also a clean, effective alternative to polluting and expensive diesel for remote islands and offshore industries, such as fish farms or oil & gas platforms.
Today, scaled and full-size wave energy prototypes are being tested at sea. The most advanced device developers are planning and building the first multi-device wave energy farms around Europe, most notably in the UK, Portugal, Spain and Italy.
Once built, these pilot farms will serve as a basis for commercialising wave energy technology and building a new European industry.
History
The first known patent to extract energy from ocean waves was in 1799, filed in Paris by Pierre-Simon Girard and his son. An early device was constructed around 1910 by Bochaux-Praceique to power his house in Royan, France. It appears that this was the first oscillating water-column type of wave-energy device. From 1855 to 1973 there were 340 patents filed in the UK alone. Modern pursuit of wave energy was pioneered by Yoshio Masuda's 1940s experiments. He tested various concepts, constructing hundreds of units used to power navigation lights. Among these was the concept of extracting power from the angular motion at the joints of an articulated raft, which Masuda proposed in the 1950s. The oil crisis in 1973 renewed interest in wave energy. Substantial wave-energy development programmes were launched by governments in several countries, in particular in the UK, Norway and Sweden.
