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.


About Pedro Ney Stroski

1 thought on “Wave power generation

  1. The power of leverage is an incredible force explained by ARCHIMEDES himself:
    “Give me a lever long enough and a fulcrum on which to place it, and I shall move the world.”

    I have a toy at home, and by using the same principle we could speed up a flywheel for free. It is called: “ HEX ROBOTICS ZIP FLYER”.

    The toy only need someone to pull a lever to activate the flying disc. Imagine a bigger and sturdier device that would be anchored in an area where waves are common. Instead of pulling a lever the lever could be push by a panel that would be facing the coming waves and the flying disc would be replace with a heavy flywheel. When the flywheel reach a certain RPM, we could connect it to a generator. Most of the power structures would be away from the elements, (salt water for example) except the panels that receive the waves.

    The panel could be attached to a lever that could be long or shorter, depending of the force or the RPM required to activate the flywheel. A gear shift similar to the one use for a bicycle could also be use to activate the flywheel.

    I know that the waves intensity varies from day to day but the generations station could be use for electrolysis (extracting hydrogen from water). I believe that, in the near future, we will have vehicles and motors operated with hydrogen not electricity. Japan is now working on the exact principle that use hydrogen to run a motor.
    I live in Canada, we have 5 Great Lakes and 2 oceans and 1 frozen most of the time but disregard that one, we should make that a reality.

    I want to save our planet and ours grandkids, I don’t have the money to attack such a project and I’m afraid that our government would put hurdles to cancel such a project since it would not bring enough money in their pockets.

    Thank you for reading me,

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