Wave energy takes advantage of the movement of ocean waves to generate electrical energy.
The energy carried by waves on the water's surface can be used to do valuable jobs: generating electricity, desalinating water, and pumping water into tanks. In addition, wave energy is a renewable energy source.
This type of energy is considered clean energy, but it carries a particular environmental impact since it modifies the coastal landscape and alters the ecosystem of the seabed.
The excitation power is estimated in kW per linear meter, that is, in kW / m. Wave energy has a much higher power density than wind and solar energy.
As a rule, the average electrical energy production of the seas and oceans exceeds 15 kW / m; with a wave height of 2 m, the power reaches 80 kW / m. That is, by developing the surface of the oceans, there can be no shortage of energy. But of course, only a part of the excitation power can be transformed into mechanical and electrical energy, but for water, the conversion coefficient is 85% higher than for air.
Generating electricity from wave energy is not a common practice. Currently, only experimental research is being carried out in this area.
In this article, we discuss what is ocean wave energy, how wave energy plants work to produce electricity, and the advantages and disadvantages of wave energy.
What is wave power?
Wave power is a type of renewable energy that harnesses the energy of waves to generate electricity. Wave power is a promising renewable energy source because it is abundant, clean, efficient, and environmentally friendly.
Wave power uses the motion of the waves of the sea to drive a turbine connected to an electrical generator.
How does wave energy work?
The different technologies to take advantage of wave energy are:
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Oscillating water column devices: This system is based on taking advantage of the pressure differences in the flow of mara water to compress air. When the compressed air is released, it drives a wind turbine that is the one that generates electricity.
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Articulated mobile devices: The water drives a hydraulic system coupled to an electric generator in these systems. With the movement of the waves, this system pumps oil at high pressure to a hydraulic motor.
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Oscillating devices: These work with a hydraulic turbine and a linear electric generator.
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Wave collectors: the collectors are fixed to the bottom of the sea. They have a water tank located at a surface higher than the water level. The action of the waves fills this reservoir and, when they return to the sea, they pass through hydraulic turbines connected to an electric generator.
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Floating structure - Wave Dragon: This system's operation principle is similar to wave collectors.
Advantages of wave power
Wave power has many advantages over other forms of renewable energy. First, wave power is a consistent energy source, as waves are created by the wind blowing over the water's surface. This means that wave power can be generated 24 hours a day, seven days a week.
A wave energy device is also a very efficient way to generate electricity. One study found that wave power can convert up to 80% of the kinetic energy from the waves into electricity. This is much higher than the efficiency of other renewable energy sources, such as solar and wind power.
Another advantage of wave power is that it does not require any fuel to generate electricity. This means that there are no emissions such as dioxide of carbon and other greenhouse gases from wave power plants, making it a very environmentally friendly form of energy.
It is an alternative to fossil fuels, reducing dependence on coal, oil, and natural gas.
Finally, wave power is a very scalable form of energy. Wave energy can be generated on a small scale (such as for powering homes) or on a large scale (such as for powering an entire city).
Disadvantages of wave power
Wave power has several potential disadvantages, which must be carefully considered before investing in this technology.
Firstly, wave power is a relatively new technology that needs to be proven on a commercial scale. There are many pilot projects worldwide, but it remains to be seen whether wave energy can be captured efficiently and economically on a large scale.
Secondly, wave power is intermittent by nature - waves only occur when the wind blows, so there is no guarantee of a constant energy supply. This means that wave power would need to be supplemented by other forms of generation, such as wind or solar, in order to provide a reliable source of electricity.
Thirdly, wave power plants can have an environmental impact on marine life in terms of their construction and operation. For example, they can interfere with shipping lanes and coastal ecosystems. Careful consideration must therefore be given to the location of any proposed wave power plant.
Finally, like all forms of renewable energy, wave power is subject to the vagaries of the weather - if the waves are not big enough, then no energy will be generated. This invests wave power somewhat riskier than other solar or wind technologies.
The cost
The biggest problem with wave power is cost.
In 1987, the Marine Science and Technology Center of the Ministry of Education, Culture, Sports, Science, and Technology conducted joint research with the International Energy Agency (IEA), with the participation of the United States, United Kingdom, Ireland, Norway, and Sweden. As a result, 1,000 kW was researched and developed. However, the power generation cost at this time was 63.2 yen/kWh, and there was absolutely no business viability.
Since then, solar and wind power have continued to be at a standstill as the cost of power generation has been steadily reduced, and a British study in 2017 concluded that commercialization is far away.
Wave Energy Technology has a price of 5 to 7 yen/kWh, and it is said to have superiority in other renewable energy and thermal power generation.
What is the difference between tidal energy and wave energy?
Wave energy is different from tidal energy.
Tidal energy harnesses the movement of the tides by converting the potential energy of water at high tide to generate electricity.
On the other hand, wave energy harnesses the power of wave motion on the ocean surface.
The energy obtained with ocean waves is much more significant than that obtained with tidal power. The dispersion of the tides caused by the influence of the Moon's gravity is of the order of 2.5 TW.
Countries with long coastlines and constant strong winds, such as the UK and Ireland, can generate up to 5% of their electricity demand from waves.
