Energy, Mechanics, New technology, Power systems, Renewable energy, Sustainability

Wave power generation

This post’s subject is wave power generation from sea. This is an alternative of clean and renewable power source which can complement with other renewable power sources.

Energetic potential

Sea waves are generated by winds, which by its turn are caused by pressure difference due to unequal incidence of solar light. Therefore, wave energy is a type of solar energy. In the figure below, the purple arrow is the wind direction from high to low pressure.

The wave energy’s potential is estimated in the total of 18,000 (TWh) (79 exaJ). One terawatt is 1\cdot 10^{12} Watts and one exaJoule is 1\cdot 10^{18} Joules. The energy density from waves is much higher than from wind. When bigger the wave’s height, bigger the potential energy. The height is determined by speed and duration of wind and deep sea`s topology.

Types of generators

Exist many types of wave power generators. In this generator, sea water enters by a duct, forming a water column which acts like a piston. This water column compress and decompress the air, turning the turbine linked to a generator.

This video shows an oscillating water column working and generating electrical energy.

This other type of generator has a floater linked to a mechanical arm, the wave motion moves the arm, which trigger the hydraulic pump in the other extremity of arm.

The hydraulic pump injects fresh water in a hydropneumatics accumulator, which is an accumulator tank of water and air.

Then the water go to a hyperbaric (high pressure) chamber as showed below.

A strong water jet is released in the output, turning a turbine.

This is Pelamis, a type of generator which remembers a serpent.

The Pelamis bend itself with sea waves and your joints have hydraulic cylinders.

The hydraulic rams pump oil to an accumulator and a hydraulic motor linked to a generator. Submarine wires link the generator to electric grid.


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About Pedro Ney Stroski

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