What is Wind Farm?
A wind farm or wind park also called a wind power station or wind power plant is a group of wind turbines in the same location used to produce electricity. Wind farms vary in size from a small number of turbines to several hundred wind turbines covering an extensive area. Wind farms can be either onshore or offshore.
Wind farms are areas in which many large wind turbines have been grouped together. You “harvest” the power of the wind. These big turbines look a bit like super-tall windmills.
In a large wind farm, hundreds of wind turbines can be distributed over hundreds of kilometers. The land between the turbines can be used for other purposes, such as regular farming. Some wind farms are also located near bodies of water. There they use winds that blow over lakes or oceans.
Did you know that wind energy is actually another form of solar energy? The shape and rotation of the earth affect the uneven heating of the atmosphere by the sun to create winds.
Wind farms are set up in areas that are known to be particularly windy on a regular basis. The winch turns the blades of the turbines. Then the turbines convert the wind’s energy into mechanical power. Generators then convert the mechanical power into electricity. This electricity is then used to power households.
You can think of a wind turbine as the opposite of a fan. A fan uses electricity to generate wind. Wind turbines do the opposite: they use the wind to generate electricity! When the wind turns the blades of a wind turbine, the blades cause a shaft to turn. The rotating shaft is connected to a generator that generates electricity.
If I tell you this, you can generate wind energy at your home. Surprising buts it’s true check out the article: How to Build a Home wind turbine?
Types of Wind Farms
There are two types of wind farm
- Offshore Wind farms
- Onshore Wind Farms
Offshore wind farms
Offshore wind energy or offshore wind energy is the use of wind farms that are built in bodies of water, usually in the ocean, to generate wind energy to electricity generation. Compared to land, higher wind speeds are available offshore, so the electricity generation of offshore wind energy per installed capacity is higher.
Offshore wind energy is the clean and renewable energy that is obtained by harnessing the power of the wind on the high seas, where it reaches a higher and more constant speed than on land due to the lack of barriers.
In order to be able to make optimal use of this resource, megastructures have been installed that sit on the seabed and are equipped with the latest technical innovations. Discover what these real sea giants look like and how they work.
How Offshore Wind Turbines Work Step by Step:
- The force of the wind turns the blades.
- The blades are attached to the nacelle through the hub.
- The low-speed shaft spins at the same speed as the blades (7 – 12 turns per minute).
- The gearbox increases this speed more than 100 times and transfers it to the high-speed shaft.
- The high-speed shaft (+1,500 revolutions per minute) transmits this speed to the generator.*
- The generator transforms the kinetic energy it receives into electricity.
- The electricity produced by the generator is fed down through the inside of the tower.
- The converter converts the direct current into an alternating current.
- The transformer raises the voltage (33 kV – 66 kV) in order to transport it across the wind farm.
- The electricity is transmitted via underwater cables to the substation.
- At the substation, the electricity is converted to high voltage current (+150 kV).
- Electricity is transported through the distribution network until homes.
Types of offshore wind turbines
fixed foundation offshore wind turbines are typically considered technically viable in areas with a water depth of less than 50 meters and an average wind speed of more than 7 meters per second (23 ft/s).
1. Fixed foundation offshore wind turbines
With the exception of a few pilot projects, almost all offshore wind farms currently in operation use turbines with a fixed foundation. Fixed foundation offshore wind turbines have fixed underwater foundations and are installed in relatively shallow waters of up to 50 to 60 meters.
Types of underwater structures include monopile, tripod, and jacketed, with various foundations at the sea floor including monopile or multiple piles, gravity base, and caissons. Offshore turbines require different types of bases for stability, according to the depth of water.
2. Floating offshore wind turbines
For locations with depths of more than 60–80 m, fixed foundations are uneconomical or technically not feasible, and floating wind turbines anchored to the ocean floor are needed.
3. Vertical-axis offshore wind turbines
Although the vast majority of currently installed onshore and all large offshore wind turbines are horizontal axes, vertical axis wind turbines have been proposed for use in offshore installations. Thanks to the offshore installation and its lower center of gravity.
These turbines can in principle be built larger than horizontal-axis turbines, with proposed designs of up to 20 MW of capacity per turbine. This could improve the economies of scale of offshore wind farms. However, there are currently no large-scale demonstrations of this technology.
What Are The Advantages Of Offshore Wind Energy?
- Offshore wind energy is renewable, unlimited and environmentally friendly.
- There are more wind resources offshore than on land (up to twice as many as in a medium-sized onshore wind farm).
- If you are offshore, the visual and acoustic impact is very small, so much larger areas can be used. Thanks to this, offshore wind farms usually have an installed capacity of several hundred megawatts.
- The ease of maritime transport, with few restrictions on cargo and dimensions compared to land transport, has enabled offshore wind turbines to achieve much larger unit capacities and sizes than onshore wind turbines
Onshore Wind Farms
Onshore wind farms are infrastructures that generate electrical energy, with the wind occurring in terrestrial locations. To do this, we first design and build devices that can convert kinetic energy from the wind into electricity, and then convert it into usable electricity before sending it to the distribution grid.
Wind energy is generated by converting the movement of air currents into electrical energy. In order to use the wind produced on land, huge wind farms are being built that are able to draw maximum electricity from this clean, renewable resource. Let’s explain how it works.
How Does An Onshore Wind Farm Work?
Electrical energy is generated in a wind turbine. This is a structure supported by reinforced concrete foundations for stability and functionality. It has a controller that starts and stops the turbine based on weather conditions and a mechanism that determines the wind direction to allow for correct alignment. The tower, the height of which depends on the characteristics of the land, has a beacon system with specific lights and colors that make it highly visible to air traffic for maximum safety.
The force of the wind turns the blades, which are designed to capture maximum kinetic energy: they can move from as little as 11 kilometers per hour even in very light winds. The blades are connected to the turbine via the hub, which in turn is connected to the low-speed shaft, which rotates at the same speed as the blades (between 7 and 12 revolutions per minute).
A gearbox increases this speed by more than 100 times and transfers it to the high-speed shaft, which moves at more than 1,500 revolutions per minute. This power is transferred to the generator (some technologies use low-speed generators coupled directly to the slow shaft) where the kinetic energy is converted into electrical energy. From here it goes to the converter, which converts it into alternating current.
The electrical energy produced is low voltage and is therefore transported to a transformer that increases the voltage (between 20 and 66 kV) that is to be transported through the farm. It is then transported to the substation, which converts it into high-voltage electricity (more than 132 kV). This electricity, which is now suitable for consumption, is transmitted via the evacuation line (usually overhead) via a system connected to the distribution network, which leads it to the households.
Where Can Offshore Wind Farms Be Installed?
Wind farms are usually located in unpopulated rural areas far from towns and cities, to prevent the noise they make from disturbing inhabitants.
There are several factors to take into consideration when deciding where to build a wind farm:
- Environmental impact.
- The energy potential of the area.
- The spacial, time and vertical wind variations over the years.
- The geological and geotechnical conditions of the site.
- Environmental, legal and territorial viability, and the accessibility of the location.
There are meteorological tools and models that make it possible to determine the best locations for the installation of wind turbines and to estimate its production capacity throughout its useful life before the wind farm is built.
What Are The Benefits Of Onshore Wind Farms?
- They are an inexhaustible source of clean, secure, renewable energy.
- They reduce fossil fuel consumption, which helps to prevent climate change and to process towards the energy transition.
- There is virtually no waste and they produce neither toxic gas nor radiation.
- They are mobile installations, which means that the site can be recovered once the farm is dismantled.
- The maintenance costs of wind turbines are minimal.
- Wind farms do not interfere with agriculture or livestock farming around the facilities.
- They create jobs. According to the report Wind energy in Europe: scenarios for 2030 by WindEurope, published in September 2017, the wind power industry will create 569,000 jobs by 2030.