Ocean Wave Energy Harvesting System | Advantages,Disadvantages
This page covers Working of Ocean Wave Energy Harvesting System used to generate electricity. It mentions benefits or advantages of Ocean wave energy conversion (WEC) system and drawbacks or disadvantages of Ocean WEC system.
There are numerous techniques which are used to generate electric energy from natural energy sources around us. For example, Light energy is used in solar cells to produce electric energy using photo-voltaic technique. EM (Electro-Magnetic) energy is used in RF energy harvesting to generate electric energy. Thermoelectric generators are used to convert temperature differences in our environment into electrical voltage in thermoelectric energy harvesting. Kinetic energy is used in piezoelectric, electromagnetic and electrostatic techniques.
What is Ocean Wave Energy Harvesting ?
Ocean waves are produced by the wind when it blows across the sea surface. During this process, wind energy is being transferred to the waves. This wave energy is converted into electric energy using various energy conversion techniques.
Wave power captured from ocean waves has many applications which include electricity generation and distribution, water desalination, pumping of water etc. Many countries inluding USA, UK, Canada, Australia, New Zealand are supporting development of ocean energy based systems.
As shown in the figure, different types of devices are used for ocean wave energy harvesting as per application requirements. This includes surface attenuators, overtopping system, Point absorbers, Oscillating water column, oscillating wave surge converter, tidal energy etc.
Attenuators : These devices are installed perpendicular to length of the sea waves.
Several such sections are connected using joints which allows attenuators to undulate along movement of waves.
Hydraulic cylinders (i.e. pumps) are being pulled due to wave movements which causes compression of fluids.
This action creates electrical current.
Overtopping : This technology is similar to hydro-power dam. The design allows water to be collected at the center called reservoir where water is stored. These water is made to pass through the several hydro turbines. The pressure of the water spins the turbines which causes ocean energy to be converted into electrical energy. Magnetic generator based overtopping system can withstand environmental hazards.
Point Absorber : This technique uses a device called "buoy" which floats above the ocean water and moves up and down as per movement of waves which causes electric power generation. Multiple such units are installed as per electricity requirements.
Working of Ocean wave energy conversion System
Wave energy is created by movement of surface of the ocean back/forth and up/down. This energy is captured and converted to electrical power. This wave energy has capability to provide 10% of energy need of the entire world.
As shown in the figure, as the wind passes over ocean surface, its kinetic energy is transferred to the water which forces water to pass through the turbine generator. The force of water on blades rotates the rotor shafts of this turbine generator. As a result, generator converts mechanical energy (i.e. kinetic energy) to the electrical energy. As described above, various Ocean wave energy conversion devices are used for such wave power based system as per their performances and application requirements.
Benefits or advantages of Ocean wave energy conversion
Following are the benefits or advantages of Ocean wave energy conversion:
➨The energy produced here is renewable as wave energy will never run out unlike fossil fuels.
➨This technique does not create harmful by-products such as waste, gas, pollution etc. It produces very little environmental impact which is not visible from shore.
➨The system is not expensive to maintain.
➨The energy produced is free for use.
➨Wave power is nearly unlimited and more predictable compare to wind and sun based power systems.
➨The wave power system produces great amount of electrical energy which is very useful to the power consumption of the large part of the world population.
Drawbacks or disadvantages of Ocean Wave Energy Harvesting
Following are the drawbacks or disadvantages of Ocean Wave Energy Harvesting:
➨Power plants and areas near the ocean can only benefit using this technique.
➨It will have effect on marine ecosystem.
➨The electricity generation is random and not continuous. Hence ocean wave energy technique requires site where waves are always strong in order to get continuous electricity generation.
➨The system should sustain very rough weather conditions in order to be functional.
The ocean wave energy is better than other renewable energies as it is available 24/7 on 365 days. Wave energy contains about 1000 times kinetic energy of wind. Wave energy has highest energy density among all renewable energy sources. Waves are more predictable compare to winds and waves keep rolling even after wind stops.