Wind energy: how does an onshore wind farm work?

Wind energy is based on harnessing the force of the wind to generate electricity, but do you know what is behind this whole process and how an onshore wind farm works?

Everyone has seen one of these wind-powered devices that we wrongly call “windmills”; whether in their surroundings, on an endless car journey full of horizons to discover, or through a screen. Wind turbines, which is what those in charge of transforming the designs of Aeolus into an inexhaustible source of renewable energy for our use are really called, are technologically advanced devices that bear many aesthetic similarities to the mills that have historically populated the landscapes of many countries (mainly dedicated to grinding grain thanks to a mechanical action resulting from harnessing the wind); Although the use of energy and its conversion into electricity, in addition to many other things that we will see later, makes them very different in turn. So, let’s see how an onshore wind farm works and who are the actors behind this type of green energy.

To understand how wind energy works, the first thing to remember is that a wind turbine is not an individual element, but rather part of a larger and more complex entity: a wind farm. While individual wind turbines do exist in the case of small consumers, that’s another story. This wind turbine is connected, both from an electrical point of view and from the point of view of sending and receiving information, with the rest of the wind turbines and elements of different kinds that make up a farm. Thus, at all times the company operating said park is aware, thanks to the sensors and intercommunication of the different elements, of the real-time status of each wind turbine: mechanical problems, generated energy, electronic problems, technical stops…

This is why, for the entire set to function properly, an onshore wind farm is made up of the following elements:

Main parts of a wind farm Land-based

• Wind turbine: This generates electricity through the physical action of the wind on the blades, which are connected to the rotor by an element called a hub. Each wind turbine can have a power that varies from 0.5 to 7 MW, depending on its size. The generated energy is already output at medium voltage thanks to the medium voltage transformer and cells housed inside in most cases, or at the foot of the wind turbine in exceptional cases.
• Medium voltage electrical grid: These are the arteries of the wind farm through which the electricity flows on its way out to consumption.
• Substation or connection point: This element is responsible for raising the generation voltage to the transport voltage and pouring the generated energy into the transport or distribution electrical grid.
• Transmission or distribution lines: Highly recognizable actors, thanks to their distinctive towers, and which are responsible for transporting green energy to our homes.

In this way, once the wind turbine starts operating, through the rotational movement, it causes the generator installed in the nacelle, produces electrical energy by transforming mechanical energy into electrical energy. In turn, the transformer raises the voltage to avoid electrical losses, and the energy is dumped into the medium-voltage grid, where it runs through underground wiring (in some countries like the USA or Brazil this route is aerial) along with the energy generated by other wind turbines. At this point, the electrical energy reaches the transformer substation to be raised to high voltage and facilitate its evacuation to the transmission or distribution network; distributed to the final consumer thanks to the role of the high and medium voltage transmission lines located in the electrical towers.

What parts does a wind turbine consist of?

Now that we know the basic operation of the onshore wind farm, it is time to zoom in on the wind turbine as an individual element, since its operation explains, at its core, how the energy generated by the wind is first converted into mechanical and then into electrical energy. To do this, let’s first look at the parts that make up these modern rivals of Don Quixote.

Wind energy: Main elements of a wind turbine

1. Blades: They are the visible protagonists that collect the energy of the wind and transform it into mechanical energy that drives the rotor. Its dimensions are gigantic, ranging between 40 and 165 meters in diameter depending on the model.
2. Rotor: This element, similar to the rotor of an airplane with a propeller, is formed by the hub, which is the connection point for the blades, joining them in a set of pieces, and allowing the movement of the wind to be transmitted to the interior of the gondola.
3. Gondola: Far from being a Venetian boat, this part is a sort of room that contains complex elements, essential for converting the mechanical energy of rotation into electrical energy.
   1. The gearbox: It is mainly responsible for generating speed changes within the machine to pass the mechanical energy to the generator.
   2. The generator: It is responsible for converting the kinetic energy of the wind into electrical energy.
4. Tower: In addition to being a simple giant pole on which the structure of the blades and the gondola is erected, This large cylinder contains essential elements for the correct distribution of electricity:
   1. Wiring: It runs inside the tower and transports the newly created electrical energy through the internal elements.
   2. Transformer: This element, which can be inside or outside the tower itself, is responsible for raising the electricity to medium voltage to avoid losses.
   3. Medium voltage cell: It is a critical element similar to a domestic switch; it is a mechanical switching device (opening and closing) that allows the generated current to be transported or its flow to be interrupted both under normal circumstances and under specific abnormal conditions. Its fundamental function is to protect the transformer from potential problems.
5. Foundation: This is the element that supports the weight of the entire wind turbine assembly, anchoring it to the ground.
6. Medium voltage network: The arteries that run through the entire installation and allow the generated renewable electrical energy to be evacuated.

Do you have any questions about how wind energy reaches your home? Take a look at this video: