Wind energy is one of the most abundant and cleanest types of renewable energy available anywhere, but is wind energy renewable? Moreover, it is considered to be the cleanest energy on the planet.
Is wind energy renewable? Why?
Yes, it is. As it uses the wind to generate power, it’s is considered a renewable source of energy since the wind will always exist and wind turbines don’t burn any natural resource to create eletricity.
Therefore, wind energy is a great alternative to fight climate change.
Renewable energy sources
The energy sources that belong to this group are considered inexhaustible, because their quantities are constantly renewed as they are used.
Examples of renewable sources are:
- hydro (energy from river water);
- solar (energy from the sun)
- wind (energy from the wind),
- biomass (energy from organic matter),
- geothermal (energy from the Earth’s interior)
- ocean (tidal and wave energy).
Wind energy: how it works
The term wind power describes the process by which wind is used to generate mechanical energy or electricity. People have used wind energy for more than 2000 years in grain milling and water pumping activities in order to minimize the expenditure of human and animal motive power.
Different types of turbine are deployed to meet the specific needs of consumers, including agricultural, industrial, commercial, government, institutional, and residential. Just one 4.8 W turbine is capable of supplying the consumption to supply 7,500 homes.
Brazil, for example, is one country that has a great energetic potential for wind power generation. Moreover, if external factors such as air quality, human toxicity or climate change are taken into account, wind energy is cheaper than energy produced with coal, gas or nuclear power.
Depending on where the wind turbines are installed, the wind energy produced can be either onshore or offshore.
- Onshore wind energy produces electrical energy using the wind from wind farms located on land.
- Offshore wind energy, on the other hand, is obtained from the force of the winds produced offshore.
Globally, Scotland has the largest floating offshore wind farm in the world. The Kincardine Offshore Windfarm is capable of supplying 55,000 homes. In Brazil, although there are already some projects, this market is still under regulation.
Types of wind energy systems: isolated, hybrid or grid-connected systems
One of the pioneers when it comes to wind energy is Denmark. It was the first country to install an onshore wind farm, which was the Vindeby wind farm near Lolland.
Furthermore, Denmark’s onshore wind energy is among the best in the world. Wind energy plays such an important transformational role in the country that Denmark will no longer be dependent on fossil fuels by 2050.
The wind system also has 3 forms of applications, and can consist of:
- stand-alone systems
- hybrid systems
- grid-connected systems.
Isolated systems are small and are commonly used to supply regions where grid extensions are not feasible. The hybrid system, on the other hand, uses more than one source to generate energy, such as solar and wind power.
The hybrid system is generally used in places where the number of inhabitants is larger. Finally, the grid-connected system uses a large number of aerogenerators (turbines), constituting a wind farm.
In this way, all the energy produced is distributed directly to the electric grid.
The principle of operation of aerogenerators or wind turbines
The aerogenerators (wind turbine or wind generation system) are the equipment known as the giants of renewable energy, responsible for transforming the kinetic energy of the wind into electrical energy.
Their working principles consist of a wind turbine that transforms wind energy into electricity using the aerodynamic force of the rotor’s wind blades.
They work like the rotor blade of a helicopter, lowering the air pressure on the other side of the blade when the wind flows between them.
The blades capture the wind, converting its power to the center of the rotor. In this way, the force of sustentation of the tower, the element that supports the rotor, is greater than the drag, and this enables the engine to turn.
One tower is capable of supporting the weight of up to 15 adult elephants, such is its structural component.
The heaviest component of the system is the nacelle, which is fitted with brakes that allow the movement of the blades to be stopped when no electricity is needed and is installed at the top of the tower.
The rotor, which is a fastening element for the blades, transmits the rotational motion to the axis of movement through the gearbox and connects to the electrical generator.
The electrical generator converts mechanical energy into electrical energy.
This connection between the rotor and the generator can be either directly, through a drive turbine, or through a shaft and a series of gears (gearbox or multiplication/transmission gearbox) that accelerate the rotation and allow for a physically smaller generator.
The proper positioning of the turbines (or wind turbines) is done with the aid of the anemometer, which measures the instantaneous local wind speed, and the windstorm, which is a meteorological item that sits next to the anemometer and is able to measure the instantaneous wind direction of the incident wind, which ensures full operation and optimization for energy production of the machine.
At the end, is this process that makes wind power a green energy source, wind energy carbon footprint is one of the best for the environment.
Wind turbines: how are their components manufactured?
Here you can find how wind turbines are made:
Blades and wind turbines
Wind turbine blades are commonly made of composite materials, such as fiber-reinforced polymers (plastics). The most commonly used materials in the manufacture of wind turbine blades are fiberglass-reinforced polyester or epoxy.
Another material used as reinforcement is carbon fiber or aramids. These materials are light and strong, however they are more expensive than steel wind blades.
The high recycling rate of steel has led companies to create steel wind blades, which cost up to 90% less than wind blades made from fiber-reinforced polymers.
This type of material is used in blades for small wind turbines and are made entirely from formed metal, and are significantly more environmentally friendly since much of the steel can be recycled.
The materials used in each of their components play a fundamental role in their performance. Generally they are built using metal, fibers and even wood, while other small generators use aluminum or composite materials, such as fiberglass.
Main components for tower construction
The towers are built of steel and concrete, and can reach an average height of 110 to 130 meters. It supports a giant weight, so it must go through an adequate construction process.
They are composed of several rings, also known as staves. These rings get smaller as it gets closer to the top of the tower.
Inside the rings, ensuring structural stability, there is a rebar steel reinforcement. There are also prestressing channels, used to connect the staves (rings) and make them monolithic, i.e., behave as a single rigid system, giving rise to prestressed concrete.
The latest technology for tower construction comes from Sweden, where researchers at the Swedish Wind Energy Technology Center are building the first wind tower out of wood. This major breakthrough will make the wind turbine completely carbon-neutral. What’s more, they are significantly cheaper than steel and concrete towers.