One way to produce electricity in a sustainable way is by harnessing the force of the wind. Windmills are a type of electrical generator that transforms the kinetic energy of the wind particles into electricity.
This type of clean energy is called wind power and is considered a renewable energy source. Wind installations are often complemented with photovoltaic panels to compensate for one of the disadvantages of solar energy: the production of energy when there is no solar radiation.
What Is Eolic Energy?
Wind energy is a source of energy that is fed by the force of the wind. Wind systems take advantage of the kinetic energy of the wind generated by the effect of air currents to transform it into electricity or other forms useful for human activities.
Why Is Wind Energy Important?
Wind energy is important because it is renewable energy that represents an alternative to fossil fuels.
Wind systems do not emit greenhouse gases, therefore they do not contribute to Earth's climate change. In addition, this source of energy offers many other advantages: it is abundant, renewable and clean. For this reason, it is considered a type of green energy.
Origin of Wind Energy, How Is the Wind Produced?
The origin of wind energy is the wind and the wind is generated by solar radiation, the Sun.
Wind energy is indirectly dependent on solar energy. When the Sun heats up the air it changes density. The difference in density between different air masses causes an upward and downward movement of these air masses. Dense (cold) air weighs more and tends to go down.
When the air rises, it leaves an empty space that is immediately filled with another mass of air that is next to it, generating a horizontal movement. This movement is due to the pressure difference, that is, when the air rises and leaves an empty space, it generates a depression.
The sum of these vertical and horizontal movements generate air currents, that is, the wind. These air currents can occur locally, but sometimes more globally. The origin of the wind is the heat generated by the Sun, but the Sun can only heat half of the Earth.
The Importance of the Oceans in the Wind
Between 1 and 2% of the energy coming from the Sun turns into wind. During the day, the air masses over the oceans, seas, and lakes remain cold relative to neighboring areas on the continental masses.
The continents absorb a smaller amount of solar radiation and, therefore, the air above the earth expands, becomes lighter and rises. The colder and heavier air that comes from the seas, oceans and great lakes is set in motion to take the place left by the hot air.
How Is the Wind Transformed into Energy?
In order to take advantage of wind energy in an efficient way, it is convenient to study some data. It is important to know:
The diurnal and nocturnal and seasonal variations of the winds
The variation of the wind speed with respect to the height above the ground
The entity of the bursts in short periods of time, and maximum values that occurred in historical data series with a minimum duration of 20 years.
The maximum speed of the wind. To be able to use the energy of the wind, it is necessary that it has a minimum speed of 12 km / h, and that it does not exceed 65 km / h. Wind turbines have a maximum capacity that, if exceeded, must be stopped for safety.
Wind energy is used through the use of wind machines (or wind turbines). These machines are capable of transforming wind energy into rotating mechanical energy.
The kinetic energy of the wind moves a propeller and by means of a mechanical transmission system, the rotor of a generator, usually an alternator, is rotated, which produces electrical energy.
In the latter case, the conversion system, which comprises a kinetic generator with its control and connection systems to the electrical grid, is known as a wind turbine.
What Are Wind Farms?
Wind farms consist of several wind turbines implanted in the territory connected to a single power line.
The low energy density of wind power per unit area, has as a consequence the need to install more machines to take advantage of available resources.
How Can We Harness the Energy of the Wind?
Historically, the energy of the wind has been harnessed since ancient times to move sail-powered ships or run windmill machinery by moving their blades.
However, the most common use is the generation of electricity through wind turbines or wind turbines that can be horizontal or vertical axis.
Small Wind Turbines
These are small plants with a nominal power between 20 kW and 200 kW. These wind generators are suitable for domestic use or to integrate the electricity consumption of small economic activities.
These plants generally consist of horizontal axis wind turbines with a rotor diameter of 3 to 20 meters and a hub height of 10 to 20 meters.
Horizontal Axis Wind Turbines
A wind turbine with a horizontal axis of rotation on the ground is made up of a steel tower tower with heights between 60 and 100 meters. At the top is a nacelle containing an electric generator driven by a rotor with blades between 20 and 60 meters long.
This generator generates a very variable power, which can range from a few kW to 5-6 MW, depending on the local wind and the weather.
High Altitude Wind Turbines
There is a relationship between the intensity of the wind and the height, the higher the height the wind speed is greater.
There are numerous projects for the exploitation of wind energy at high altitude. These projects aim at a reduction in energy production costs compared to traditional wind systems.
A high altitude windmill is a design concept for a wind turbine that sits in the air without a tower. In this way, the wind turbine benefits from the higher and almost constant wind speed at high altitude.