Everything about wave power

Sustainable electricity by harnessing energy from waves

Reading time: 6 min

Wave power is one of the most promising renewable energy sources of this decade. There are three key factors that place wave power as a good candidate to make electricity production more sustainable and environmentally-friendly:

Firstly, it must be highlighted that oceans make up more than 70% of the total surface of our planet. As a result, there is a very large territory in which to operate.
Secondly, water is a liquid with greater density than air, which means that a wave power plant can generate large amounts of energy.
Thirdly, and one of the most important factors, it is a type of renewable energy. In other words, it is obtained from unlimited natural sources that don't produce greenhouse gas (GHG) emissions

What is wave power?

Wave power makes the most of the movement of the waves to generate electricity.

Wave power is kinetic energy and mechanical energy that is transformed into electricity through different techniques, depending on the type of technology that each power plant uses.

It is obtained from natural phenomenons, so it is a renewable and clean energy source. The heating of the water depends on the sun’s radiation, the size of the waves, and the speed of the wind. Furthermore, the methods that are used to extract and transform this energy into electricity are environmentally-friendly.

When we speak about energy from the sea, we can distinguish between two types: wave and tidal power. Wave power makes the most of the force of the waves from the sea to generate electricity, while tidal power uses the difference between high and low tides.

How does a wave power plant work?

Wave power can be generated through different techniques; and each defines the type of power plant. Let’s look at the main technologies of a wave power plant:

Oscillating water column: It is used in areas where the waves are very strong. The mechanism is the following: the wave presses the air in the chambers, which rises upwards passing through the turbines and making them rotate. When the wave withdraws, the air is sucked out and also passes through the turbine. This technology makes the most of the force of the incoming and outgoing wave.

Point absorber buoy: It consists of outer buoys that are fixed to the seabed with a 100-ton anchor. Inside the post that joins the buoy and the foot there is a hydraulic system that compresses the water contained in the structure, which activates the generator that produces the electricity.

Surface attenuator: This technology is similar to point absorber buoys. In this case, they have floating segments connected to one another perpendicularly to the incoming waves. The swell produces a flexing motion that activates the hydraulic pumps that generate the electricity.

floating structure to create wave energy

Archimedes waveswing: This system is formed by a fixed structure and another movable one. The fixed one is anchored to the seabed (at a depth of 40 to 100 meters) with concrete. The air-filled movable structure moves vertically following the swell. The movement generated between the fixed part and the movable part causes the air in the floater to compress and the pressures to equalize. Thanks to the hydraulic system and engine - generator, the mechanical energy is transformed into electricity.

Floating converters: This technology is based on the same principle as oscillating wave converters, only in this case they aren’t submerged but floating. Therefore, electricity is obtained with the rise and fall of the waves. Precisely, as it is not submerged in the water, the advantage it provides is that maintenance and repair are simpler.

Oscillating wave converter: To use this technology, submerged converters are installed that oscillate with the movement of each wave. Electricity is captured from the rise and fall of the waves.

Submerged pressure differential converters: It is a more cutting-edge technology that uses large membranes that separate the water to cause different pressures between the waves and the water, and thereby extract the electricity.

Overtopping devices: Large structures are installed that harness the force and speed of the waves to fill a reservoir at a higher level than the ocean. The energy from the water that remains in the tank is captured by turbines and generates electricity.

Advantages of wave power

You could say that wave power is a relatively new type of energy. The first plant was opened in Perth (Australia) in 2014. However, its great potential makes it one of the most promising energy sources for an emission-free future.

Let’s look at some advantages of wave power:

Clean and safe energy

It doesn't generate greenhouse gas emissions, and does not discharge pollutants into the sea. It is a safe energy, as no combustion is required.

Location

Seas occupy more than 70% of the Earth's surface, so it can be installed in a large percentage of the world.

Efficiency

Water is denser than air, so it generates more energy. It is estimated that for every meter of wave height, 20 to 40 kW can be obtained.

Space

In relation to the space/performance of the facilities, wave power is highly efficient. With a surface of just over 2 kilometers, energy could be produced to supply approximately 20,000 homes.

Supply

Electricity can be produced in a specific geographic area of consumption, which makes it possible to supply areas that are difficult to access, such as islands or boats. This increases the efficiency of the electrical grid and reduces transportation costs.

Hydropower

The energy that harness the force of the water to produce electricity.

Go to Hydropower

Energy transition

Everything about tidal power

Discover all about the energy coming from tides