8 Types of Wave Energy Converters and How Each Operates

When wind passes over the open surface of lakes and oceans, waves are created. The energy of ocean waves is enormous. This ocean energy can be harnessed through different types of wave energy converters. A few of the benefits of wave energy are that it is free, sustainable, renewable, and waste-free.

As a result, it might help us lessen our carbon footprint. Being the most concentrated source of renewable energy on the planet with a power density significantly higher than that of wind and solar energy, it is also exceptional.

What is Wave Energy?

A type of energy derived from the ocean or sea waves is known as wave energy, ocean energy, or sea wave energy. Wave energy systems utilize kinetic (motion) energy from the vigorous vertical motion of surface ocean waves to perform useful tasks.

What is wave energy used for?

The wave energy that is captured is put to use for a variety of beneficial tasks, such as the creation of power, the desalination of water, and the pumping of water into reservoirs.

How is Wave Energy Generated?

The up-and-down movement of floating objects positioned on the ocean’s surface generates wave power. In other words, the wind creates the waves, which then create energy. Modern technology uses the natural motions of water currents and swells to generate power as the waves move over the ocean.

What is a Wave Energy Converter?

The kinetic and potential energy associated with a moving ocean wave is transformed into usable mechanical or electrical energy by machines called wave energy converters (WECs).

Wave energy converters can produce clean energy for a variety of uses, including pumping for saltwater desalination or propulsion for underwater vehicles. The amount of ocean energy in this form is the highest estimated worldwide resource.

Types of Wave Energy Converters

The following are some of the different technologies that are utilized for wave energy.

  • Attenuators
  • Point Absorbers
  • Oscillating Wave Surge Converter
  • Oscillation Water Column
  • Overtopping/Terminator Device
  • Submerged Pressure Differential
  • Bulge Wave
  • Rotating Mass

1. Attenuators

An attenuator is a floating object that efficiently rides waves by operating parallel to the wave direction. The relative velocity of the two arms as the wave passes them is used to power these gadgets.

They depend on the flexing of joints to provide power, and their designs are typically (but not always) modular. Imagine two barges joined together to form wings.

These gadgets make an effort to take advantage of a variety of motion translations, including, for instance, surge, sway, and heave. To maximize power from a particular wave environment, the dominant wavelength is a crucial factor in these devices.

2. Point Absorbers

A point absorber is a floating object that moves at or close to the water’s surface and absorbs energy from all directions. It generates electricity from the motion of the bouncy top about the base. Various power take-off systems are possible depending on how the displacers and reactors are set up.

These floating constructions make use of the wave motion at a single location and have a limited horizontal size compared to their vertical dimension. Most point absorber designs resemble a standard buoy, at the very least.

The point absorber is often designed with one end fixed (or at least fixed about the water’s surface) and the other end moving vertically as the wave crests and troughs lift and lower the device.

A linear generator or a fluid pump can be driven by the resulting reciprocating action, which can generate usable power. This device makes use of the up-and-down motion caused by ocean waves. One of the most common design motifs used nowadays in the marine energy industry is point absorbers.

3. Oscillating Wave Surge Converter

Wave surges and water molecule motion are converted into energy by oscillating wave surge converters. In reaction to the movement of the water in the waves, the arm swings back and forth like a pendulum positioned on a pivoting joint.

Almost always entirely submerged, these devices often sit on the seafloor in shallow water, perhaps even in the more hazardous breakwater zones.

The most basic design is a pendulum arm flap that pivots on a hinged joint and oscillates back and forth due to wave motion acting on it. The flap’s movement can be mechanically connected to a generator to generate electricity or a pump to pressurize a fluid because it behaves like a big lever arm.

4. Oscillation Water Column

At the water’s surface, oscillating water columns (OWC) frequently have an ‘L’ form. A hollow, partially submerged structure known as an oscillating water column. It contains a column of air on top of a column of water and is open to the ocean below the water’s surface.

The air column is compressed and decompressed as a result of waves raising and lowering the water column. In this concept, a bidirectional air turbine positioned on top of the platform traps air in a chamber between the water’s surface and it.

The waves’ reciprocating motion acts like a piston on the air in the chamber as they pass underneath the apparatus, increasing and decreasing the pressure there.

Air is compressed and pressure is increased in the chamber as a result of the rising water level and wave crest, which causes the turbine to spin.

When the water level recedes from the wave’s trough, it generates a little vacuum inside the chamber and draws air through the turbine from the outside, spinning it once more.

The primary shaft of the bi-directional turbine spins in a single direction, allowing it to move a vehicle even though the turbine blades on either end may spin in opposite directions.

5. Overtopping/Terminator Device

Waves breaking into a storage reservoir are captured by devices that overtop it. After producing power, a normal low-head turbine, the water is then returned to the sea. ‘Collectors’ may be used by an overtopping device to concentrate the wave energy.

This converter raises a volume of water to a height above the ocean’s surface to make use of a difference in potential energy. These gadgets mimic the wave activity that you could normally see on a beach.

Waves are focused by floating, extending arms so that they increase in height as they go closer to a man-made “beach” in the middle of the apparatus. The waves that crash into the man-made beach run up a ramp and into a storage reservoir that is elevated above the surrounding sea level.

Gravity helps the fluid flow back down from here, and the flow is then used to drive a turbine. These designs resemble hydroelectric dam construction techniques in several ways.

Be aware that for maximum effectiveness, these wave energy converters must calibrate themselves to the height of the approaching waves. Although several of these gadgets have been modified for usage offshore, they are most frequently found close to the shore.

6. Submerged Pressure Differential

Devices for measuring submerged pressure differences are usually fixed to the seabed close to the coast. The gadget experiences a pressure differential as a result of the wave’s velocity, which causes the sea level above it to increase and fall. The system’s fluid is circulated by alternating pressure to produce electricity.

There are two varieties of this type of wave energy converter. One kind of device lays on or near the seafloor and uses pressure changes caused by waves to squeeze a fluid and bend a pliable material, like an air bladder, to power a turbine or other power take-off device.

The other kind is submerged and resembles a point absorber. This kind uses waves to move a buoyant, submerged float, and a linear generator to turn the reciprocating motion into energy.

7. Bulge Wave Technology

Bulge wave technology uses a water-filled rubber tube that is tethered to the ocean floor and directed toward the waves. Water enters through the stern, and when waves pass by, the pressure inside the tube changes, resulting in a bulge.

The bulge expands as it moves through the tube, accumulating energy that can be utilized to power a typical low-head turbine at the bow, where the water is subsequently pumped back into the water.

8. Rotating Mass

Rotating mass wave energy converters are typically surface riders that power a rotational alternator with an internal weight rotating about a fixed position. The apparatus moves in waves, heaving and swaying in two directions, capturing energy in the process.

Precession is caused by this motion driving either an eccentric weight or a gyroscope. Both times, the movement is connected to a power source inside the device.

The rotating mass spins about its axis to locate a new center point as the vessel’s trim and pitch fluctuate as a result of the shifting center of buoyancy and center of gravity caused by the rocking action of ocean waves.

Waves cause the device to roll and sway repeatedly, which causes the mass to rotate constantly to find equilibrium while simultaneously producing electricity.


Why has wave energy not yet taken off?

One issue is simply that the ocean is a highly harsh environment; installing and subsequently maintaining a device in the ocean is difficult and expensive. For the same reason, it is challenging to create a wave energy capture system that will have a long enough lifetime to justify the initial outlay of capital.

Another problem is that, unlike other renewable energy sources, there isn’t yet a single “favorite” design, therefore resources are being dispersed among a wide range of extremely diverse technologies.

However, wave energy capture has a lot of potential because it is not only a reliable source of energy but also has the highest energy density of all renewable sources. For this reason alone, we believe wave energy will eventually play a significant part in the sustainable supply of energy for the entire planet.


Editor at EnvironmentGo! | providenceamaechi0@gmail.com | + posts

A passion-driven environmentalist by heart. Lead content writer at EnvironmentGo.
I strive to educate the public about the environment and its problems.
It has always been about nature, we ought to protect not destroy.

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