WAVE POWERMADE BY: Saqib Rasool

Roll No: 13-MCT-11

How Waves Form ?

Differential warming of the earth causes pressure differences in the atmosphere, which generate winds.

As winds move across the surface of open bodies of water, they transfer some of their energy to the water and create waves.

A few factors determine how strong an individual wave will be. These include: Speed of wind: The faster the wind is traveling, the bigger a wave

will be. Time of wind: The wave will get larger the longer the length of

time the wind is hitting it. Distance of wind: The farther the wind travels against the wave

(known as fetch), the bigger it will be.

Wave Power

Wave power is the transport of energy by ocean surface waves, and the capture of that energy to do useful work – for example, electricity generation, water desalination, or the pumping of water (into reservoirs).

What is Wave Energy? Some of the kinetic (motional) energy in the wind is

transformed into waves once the wind hits the ocean surface.

Wind energy ultimately forms due to solar energy and its influence on high and low pressure.

The density of the energy that is transported under the waves under the ocean surface is about five times higher compared to the wind energy 20 meter (about 65 feet) above.

In other words, the amount of energy in a single wave is very high.

History The first known patent to use energy from ocean waves dates

back to 1799 and was filed in Paris by Girard and his son. An early application of wave power was a device constructed

around 1910 . From 1855 to 1973 there were already 340 patents filed in

the UK alone. Modern scientific pursuit of wave energy was pioneered by

Yoshio Masuda's experiments in the 1940s. A renewed interest in wave energy was motivated by the oil

crisis in 1973. In the 1980s, a few first-generation prototypes were tested at

sea. In 2008, the first experimental wave farm was opened in

Portugal.

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Advantages of wave energy Renewable: The best thing about wave energy is that it will

never run out. Unlike fossil fuels, which are running out.The waves flow back from the shore, but they always return.

Environment Friendly: Also unlike fossil fuels, creating power from waves creates no harmful byproducts such as gas, waste and pollution

The energy is free - no fuel needed, no waste produced. 

Not expensive to operate and maintain. 

Can produce a great deal of energy.

It is a reliable source

Easily predictable

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Disadvantages of Wave Energy Suitable to Certain Locations:The biggest disadvantage

to getting your energy from the waves is location. Only power plants and towns near the ocean will benefit directly from it.

Effect on marine Ecosystem :As clean as wave energy is, it still creates hazards for some of the animals near it

Depends on the waves - sometimes you'll get loads of energy, sometimes almost nothing. 

Needs a suitable site, where waves are consistently strong. 

Weak performance in rough weather. Maintenance and weather effects Noisy

Harnessing Techniques

In order to extract this energy, wave energy conversion devices must create a system of reacting forces, in which two or more bodies move relative to each other, while at least one body interacts with the waves.

There are many ways that such a system could be configured.

Three Basic Kinds of Systems Offshore (deals with swell energy not breaking waves)

Near Shore (maximum wave amplitude)

Embedded devices (built into shoreline to receive breaking wave – but energy loss is occurring while the wave is breaking)

Wave Energy Devices

Wave Profile Devices: They turn the oscillating height of the oceans surface into mechanical energy.

Oscillating Water Columns: They convert the energy of the waves into air pressure.

Wave Capture Devices: They 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“.

WorkingThe waves energy is absorbed using

Vertical motion (heave)

Horizontal motion in the direction of wave travel (surge)

Angular motion about a central axis parallel to the wave crests (pitch)

or, angular motion about a vertical axis (yaw)

or a combination of all four The energy being generated by reacting these different movements

against some kind of fixed resistance called a reaction point.

Wave Attenuators As the waves pass along the

length of the device, they cause the long cylindrical body to sag downwards into the troughs of the waves and arch upwards when the waves crest is passing.

Connecting joints along the body of the device flex in the waves exerting a great deal of force which is used to power a hydraulic ram at each joint.

The hydraulic ram drives oil through a hydraulic motor which drives a generator, producing the electricity.

Oscillating Water Column (OWC)

The Oscillating Water Column, (OWC) is a popular shoreline wave energy device normally positioned onto or near to rocks or cliffs which are next to a deep sea bottom.

They consist of a partly submerged hollow chamber fixed directly at the shoreline which converts wave energy into air pressure.

OWC- Working As the incident waves outside enter and exit the chamber, changes in

wave movement on the opening cause the water level within the enclosure to oscillate up and down acting like a giant piston on the air above the surface of the water, pushing it back and forth.

This air is compressed and decompressed by this movement every cycle.

The air is channeled through a wind turbine generator to produce electricity

500 kW offshore OWC, Port Kembla,Australia

Oceanlinx’s world's first 1MW wave energy converter unit 'greenWAVE, Australia

Wave Capture Device A Wave Capture Device also known as a Overtopping Wave

Power Device, is a shoreline to nearshore 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.

It require sufficient wave power to fill the impoundment reservoir.

Working 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.

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Oscillating Wave Surge ConverterThese devices typically have one end fixed to a structure or the seabed while the other end is free to move. Energy is collected from the relative motion of the body compared to the fixed point.

These capture systems use the rise and fall motion of waves to capture energy. Once the wave energy is captured at a wave source, power must be carried to the point of use or to a connection to the electrical grid by transmission power cables.

Tapered Channel (TAPCHAN) The TAPCHAN is designed by a company called Norwave, and

a 350kW prototype commenced operation in 1985 on a small Norwegian island.

The principle behind the design is to capture waves in a raised reservoir (about 3 metres above the mean sea level) and then extracting useful work as the water is allowed to flow back to the sea.

Benefits of Ocean Wave Energy Why better than other

renewable energies Available 24/7 on 365 days -

therefore power produced from them is much steadier and more predictable – waves can be accurately predicted 48 hours in advance and therefore forecast energy output (BUT irregularity in wave ampitude, and direction)

Good data on waves from wave monitoring bouys

Wave energy contains 1000 times the kinetic energy of wind (can produce the same amount of power in less space)

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THANK YOU