Electricity From Ocean WaveElectricity From Ocean Wave

IntroductionIntroductionOcean energy is replenished by the sun and through tidal Ocean energy is replenished by the sun and through tidal

influences of the moon and sun gravitational forcesinfluences of the moon and sun gravitational forcesNear-surface winds induce wave action and cause wind-Near-surface winds induce wave action and cause wind-

blown currents at about 3% of the wind speedblown currents at about 3% of the wind speedTides cause strong currents into and out of coastal basins Tides cause strong currents into and out of coastal basins

and riversand riversOcean surface heating by some 70% of the incoming Ocean surface heating by some 70% of the incoming

sunlight adds to the surface water thermal energy, causing sunlight adds to the surface water thermal energy, causing expansion and flowexpansion and flow

Wind energy is stronger over the ocean due to less drag, Wind energy is stronger over the ocean due to less drag, although technically, only seabreezes are from ocean energyalthough technically, only seabreezes are from ocean energy

Wave ParametersWave Parameters

Causes Of WavesCauses Of Waves

WindWind

Submarine disturbanceSubmarine disturbance

Gravitational attraction of sun and moonGravitational attraction of sun and moon

Category Of Ocean WavesCategory Of Ocean Waves

Deep Water WavesDeep Water Waves

Shallow Water wavesShallow Water waves

Deep Water WavesDeep Water Waves

Waves do NOT interact with the seafloor. Waves do NOT interact with the seafloor.

Orbits of the water molecules are Orbits of the water molecules are circularcircular

Shallow Water WavesShallow Water Waves

Waves DO interact with the seafloor.Waves DO interact with the seafloor.

Orbits of the water molecules become Orbits of the water molecules become ellipticalelliptical..

Ocean Wave Energy Converted Ocean Wave Energy Converted To ElectricityTo Electricity

Distance from shore—Wave energy devices may Distance from shore—Wave energy devices may convert wave power at the shoreline, near to the shore convert wave power at the shoreline, near to the shore (defined as shallow water where the depth is less than (defined as shallow water where the depth is less than one half of the wavelength ), or offshore.one half of the wavelength ), or offshore.

Bottom mounted or floating – Wave energy devices Bottom mounted or floating – Wave energy devices may be either bottom –mounted or floating.may be either bottom –mounted or floating.

Devices Used To Generate the Devices Used To Generate the ElectricityElectricity

Point AbsorberPoint AbsorberOscillating water columnOscillating water columnOvertopping terminatorOvertopping terminatorAttenuatorAttenuator

Point AbsorberPoint Absorber

This is a bottom –mounted or floating structure that This is a bottom –mounted or floating structure that absorbs energy in all direction .absorbs energy in all direction .

The power take off system may take off number of The power take off system may take off number of forms depending on the displaces.forms depending on the displaces.

Pressure differences on the top of float set the upper Pressure differences on the top of float set the upper floater into motion.floater into motion.

Oscillating Water ColumnOscillating Water Column

At the shoreline this could be a cave with a blow At the shoreline this could be a cave with a blow hole and on air turbine/generator in the blow hole that hole and on air turbine/generator in the blow hole that and chamber developed.and chamber developed.

Wave entered and exit the chamber, the water column Wave entered and exit the chamber, the water column moves up and down and act like a piston.moves up and down and act like a piston.

The air is channeled through a turbine/generator to The air is channeled through a turbine/generator to produce electricity.produce electricity.

Overtopping TerminatingOvertopping Terminating

The head of collected water turns the turbine it flow back out The head of collected water turns the turbine it flow back out to sea and turbine are coupled to produce electricity.to sea and turbine are coupled to produce electricity.

Floating structure arms to focus the wave energy. It Floating structure arms to focus the wave energy. It has both ramp and reservoir so that as wave arrivehas both ramp and reservoir so that as wave arrive

This is a floating reservoir structure with a ramp, over which This is a floating reservoir structure with a ramp, over which the waves topple and hydro turbine/generating through which the waves topple and hydro turbine/generating through which the water returns to the sea.the water returns to the sea.

AttenuatorAttenuator

Attenuator structure that is oriented parallel to the Attenuator structure that is oriented parallel to the wave. This is called a linear absorber.wave. This is called a linear absorber.

The structure is composed of multiple section in pitch The structure is composed of multiple section in pitch & yaw related to each other.& yaw related to each other.

This motion is used to pressurize a hydraulic piston This motion is used to pressurize a hydraulic piston arrangement & turn a hydraulic turbine/ generator to arrangement & turn a hydraulic turbine/ generator to produce electricity produce electricity

Properties of Ocean WavesProperties of Ocean Waves

An ocean wave is an undulation of the sea surface.An ocean wave is an undulation of the sea surface.Wave crestWave crestWave troughWave troughWave heightWave heightWave lengthWave lengthWave periodWave period

Progressive wavesProgressive waves move across the sea surface.move across the sea surface.Standing wavesStanding waves oscillate about a fixed pointoscillate about a fixed point

AdvantagesAdvantages

Wave energy are:Wave energy are:

Free renewable energyFree renewable energyMore profitable that wind energyMore profitable that wind energyNon-polluting energyNon-polluting energy

ConclusionConclusion

Renewable but not profitable.Renewable but not profitable.This marginal system show that the sea is a vast space This marginal system show that the sea is a vast space

whose resources are not exploited.whose resources are not exploited.