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Wave Energy Devices

Devices that Harness the Energy of the Waves

wave energy iconWe have seen previously that Wave Energy is a non-polluting and renewable source of energy, created by natural transfer of wind energy above the oceans, which itself is created by the effects of the suns solar energy. As the wind blows across the oceans surface, moving air particles transfer their energy to the water molecules that they touch.

As the wind continues to blow more and more of its kinetic energy is transferred to the oceans surface and the waves grow bigger. These larger waves are called gravity waves because their potential energy is due to the gravitational force of the Earth. There is a lot of potential energy in the waves generated by the wind, to the point were large storm waves can lift ships high out of the water.




  • 1. Wave Profile Devices These are wave energy devices which turn the oscillating height of the oceans surface into mechanical energy.
  • 2. Oscillating Water Columns These are wave energy devices which convert the energy of the waves into air pressure.
  • 3. Wave Capture Devices These are wave energy devices which convert the energy of the waves into potential energy.

Wave Profile Devices



If the physical size of the wave profile device is very small compared to the periodic length of the wave, this type of wave energy device is called a “point absorber”. If the size of the device is larger or longer than the typical periodic wavelength, it is called a “linear absorber”, but more commonly they are collectively known as “wave attenuators”.




Wave Profile Devices

Wave Energy Devices

The pitching and heaving of the waves causes a relative motion between an absorber and reaction point. The left hand wave energy device above, uses a heavy ballast plate suspended below the floating buoy. The buoy is prevented from floating away by a mooring line attached to a sea-floor anchor. This mooring line allows the point absorber to operate offshore in deeper waters.



The Pelamis Wave Energy Converter

Watch the Video to Learn More.

This method of wave energy conversion is currently being used by a device called the Pelamis Wave Energy Converter developed by the “Pelamis Wave Power” company (please watch the video for more information). One advantage of the Pelamis design is that several offshore devices can be connected together and linked to the shoreline through a single submersible underwater cable.

Oscillating Water Column



Oscillating Wave Column

Oscillating Wave Column





Wave Capture Device

A Wave Capture Device also known as a Overtopping Wave Power Device, is a shoreline to near shore wave energy device that captures the movements of the tides and waves and converts it into potential energy. Wave energy is converted into potential energy by lifting the water up onto a higher level. The wave capture device, or more commonly an overtopping device, elevates ocean waves to a holding reservoir above sea level.

The overtopping wave energy converter works in much the same way as an impoundment type hydroelectric dam works. Sea water is captured and impounded at a height above sea level creating a low head situation which is then drained out through a reaction turbine, usually a Kaplan Turbine generating electricity as shown.

Wave Capture Device

Wave Capture Device

The basic impoundment structure can be either fixed or a floating structure tethered to the sea bed. The wave overtopping device uses a ramp design on the device to elevate part of the incoming waves above their natural height.

As the waves hit the structure they flow up a ramp and over the top (hence the name “overtopping”), into a raised water impoundment reservoir on the device in order to fill it. Once captured, the potential energy of the trapped water in the reservoir is extracted using gravity as the water returns to the sea via a low-head Kaplan turbine generator located at the bottom of the wave capture device.


We now know how wave energy works and one of the main advantages of “wave energy devices”, is that besides the generating turbine there are no moving parts. Unfortunately, shoreline overtopping schemes have a relatively low power output due to their low head and are only suitable for sites where there is a deep water shoreline and a low tidal range of less than about a metre. To overcome some of these limitations, floating offshore capture devices have been developed, but they too require sufficient wave power to fill the impoundment reservoir.

We have seen above, some of the wave energy devices which are currently being used to extract electrical energy from wave energy. Mother nature provides a large supply of renewable wave energy every day and the technology already exists for extraction of this free energy but there are many technical challenges to be solved with the main barrier preventing wave energy from being a common form of power generation is the actual energy carrier itself: “the sea”.

The capture of wave energy has to face various problems. For example, wave energy devices are exposed to hard weather conditions, with some devices already been destroyed by the forces of tides and strong storms. Accessibility, maintenance and repair can also be costly, with the typical efficiency of a wave energy device at the moment being only about 30%.

However, if the technology and efficiencies are improved offshore wave energy can provide many advantages compared to other forms of renewable energy sources. One of its main advantages is that wave energy is generally considered to provide a clean source of renewable energy with limited negative environmental impacts with very low or zero CO2 emissions.

Sea waves have high energy densities, the highest among renewable energy sources with the natural seasonal variability of wave energy following the electricity demand in temperate climates securing energy supplies in remote regions. Wave energy also has negligible land use and large scale implementation of wave power technologies could help stimulate declining shipbuilding and dockyard industries that could help fabricate these metal bodied wave energy devices.



10 Comments » for Wave Energy Devices
  1. Aedan Aedan says:

    thanks, there’s not alot of these types of websites with solutions to climate change that involve using sea energy. all tho there are some things missing like…

    – Eco wave power
    – Wave roller

    you should probably update this website… :0
    but this is good material and this helps me with my project 🙂

  2. George Alan Busby George Alan Busby says:

    The most efficient way to capture and store wave energy is by building reservoirs at sea that have one way openings in their sides. The pressure from the incoming wave forces water into the reservoir through the openings. This will raise the water level in the reservoir above sea level. The resultant head of water can be used to generate electricity. As the reservoirs block the forward motion of waves they are also effective breakwaters

  3. mabrouk alajeli mabrouk alajeli says:

    the only hope for human beings to countinue their life on the earth is to use clean energy sources

  4. mabrouk alajeli mabrouk alajeli says:

    if we use sea waves power effectively and transfer this huge amount of energy to the land we will save our planet so all countries of the world must direct to this kind of energy to save our environment to secure new generations future

  5. LuckGems LuckGems says:

    can you explain ore and can tell e how can i calcuate it

  6. Andra Andra says:

    Could you tell me where I can found some information about the wave-height in the NW part of Black Sea for the last 6 years? I want to do a study about the wave-height and I don-t know where I can find information/databases.
    Thank You!
    Andra T.

  7. Cosma Vasile Cosma Vasile says:

    Cosma Vasile Romania.

    – Ocean energy: Wave energy | Climate TechWiki

    Link for patent “Dynamic Engine”


    it gave me good ideas for my project to complete effectively and efficiently.

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