Wave Power
DEFINITION & TYPES OF STRATEGIES
Ocean wave energy is the energy that is transferred from the wind to the ocean.The wind blows over the ocean and the air-sea interaction transfers energy from the wind to the water, forming waves that store the energy as:
- Potential energy : the water body displaces from the mean sea level.
- Kinetic energy: the water particles motion.
The size and period of the waves depend on:
- Wind speed: the amount of energy that is transferred.
- Length of time the wind blows.
- Length of ocean over which the wind blows.
Most energetic waves can be found between 30º and 60º latitudes by extra-tropical storms. The largest power levels occur off the west coasts of the continents in temperate latitudes, where wind is the most energetic.
POINT ABSORBERS
A point absorber buoy is a device that could potentially provide a large amount of power in a relatively small device, compared to other technologies. This device floats on the surface of the water, held in place by cables connected to the seabed. Point absorbers are small compared to wave length, and may be bottom mounted or floating structures.The vertical motion of the buoy is utilized to alternate the compression of a gas or liquid in some form of container, converted into rotational movement of the power generator, or converted in other similar ways. The relative motion between the wave-activated float on the sea surface and the seabed structure activates a power takeoff system.
SURFACE ATTENUATOR
Surface attenuator is similar to point absorber buoys with the difference of having multiple floating segments connected to one another and oriented perpendicular to incoming waves. A flexing motion is created by swells that drive hydraulic pumps to generate electricity.
OSCILLATING WATER COLUMNS (OWC)
OWCs are devices that generate energy from the rise and fall of water caused by waves and tides.
Basic OWC Components are:
- Collecting Chamber: has a wide bottom that is open in the ocean and submerged.
- Power-Take-Off. It converts airflow going into energy. It has bidirectional turbines.
- Wells Turbine. Well turbine a bidirectional turbine that uses symmetrical airfoils. Wells turbines are most efficient at low speed wind.
- Overtopping devices