Green Energy means not the color of energy. A green energy is that source of renewable energy which you can use again and again without environmental damage.
The renewable energy examples are solar energy, wind power, geothermal energy, nuclear energy, hydroelectric energy etc.
Out of above alternative energy sources, you will get detail information on solar energy from below article.
Recommended Reading: A Comprehensive Guide on Solar Energy you shouldn’t Miss
In last four decades, an extensive research and development on green energy have been done by engineering concerned. These efforts opened hundreds of new technologies that can reduce our dependence on non renewable energy. The non renewable energy examples are coal, oil, and natural gas.
Advance technology in green energy technologies has lowered the cost of wind turbines. Hence nowadays its possible to produce cheap electricity by wind power.
Green energy has potential to replace fossil fuels in all major areas of use including electricity, space heating, and automobile industry.
This guide on green energy source includes all the essential information regarding the generation of electricity utilizing the wind energy. Here you will find the information on the history of wind energy, types of wind turbines, wind power plant, benefits of wind energy, advantages of wind power etc.
So, let’s move further to gain the information on wind power.
History of Wind Energy
People have been using wind energy for thousands of years. Sailboats and sailing ships have been using wind power for at least 5,500 years.
In the 17th century BC, the Babylonian emperor Hammurabi planned to use wind power for his ambitious irrigation project.
The first practical windmills were in use in Sistan, at least by the 9th century and possibly as early as the 7th century.
The use of windmills became widespread across the Middle East and Central Asia and later spread to China and India.
By the 14th century, Dutch windmills were in use to drain areas of the Rhine River delta.
In Greece, windmills were used to mill flour and remained in use until the early 20th century.
To utilize this green energy, the first windmill for electricity production is built by Professor James Blyth in 1887. Three wind turbine design is prepared for the experiments. The last one gave power for 25 years.
In 1887, Professor Charles F. Brush builds a 12kW wind turbine to charge 408 batteries. The turbine used in this experiment runs for 20 years.
The first vertical axis wind turbine, the Darrieus turbine, is invented by Frenchman George Darrieus in 1920.
In 1931, a precursor to the modern horizontal wind generator is used in Yalta, generating 100kW.
The world’s first-megawatt wind turbine is built and connected to the power grid in Castleton, Vermont in 1941.
In 1980, world’s first wind farm consisting of 20 turbines is built in New Hampshire.
What are the different types of wind turbines used to utilize the green energy?
A wind turbine is a machine which is used to convert the kinetic energy of flowing wind into mechanical energy. Wind turbines convert wind energy into electrical energy for distribution.
If the mechanical energy is directly used by pump or grinding stones, the machine is usually known as a windmill.
Wind Turbine is generally classified as horizontal axis wind turbines and vertical axis wind turbines.
Horizontal Axis Wind Turbine (HAWT)
The shaft of a turbine is horizontal to the ground. Hence this turbine is called as the horizontal axis wind turbine.
Horizontal axis wind turbines or HAWT, are the common type of wind turbine used to generate the electricity nowadays.
All the key components of this type of turbine are mounted at top of a tall tower. A Horizontal-axis turbine has three blades like an airplane propeller.
The wind hits the blades of the turbine that are connected to a shaft causing rotation. The shaft is coupled with a gearbox at the end which rotates the generator.
The generator produces electricity to send it into the power grid.
Large turbines generally use a wind sensor coupled with a servo motor to turn the turbine into the wind.
In case of extreme winds, the turbine has a break system to slow down the shaft speed. This will avoid any damage to the turbine in extreme conditions.
Vertical Axis Wind Turbine (VAWT)
The main rotor shaft of a turbine is arranged vertically. Hence this turbine is called as the vertical axis wind turbine.
With a vertical axis, the generator and other primary components can be placed near the ground. So, the tower does not need any support. This arrangement also makes turbine repair easy to wind turbine technician.
The main advantage of this arrangement is that the wind turbine does not need to be pointed into the wind.
For maximum wind energy and minimum wind turbulence, the height of the rooftop mounted turbine tower must be 50% of the building height.
VAWT is subdivided into a darrieus wind turbine and savonius wind turbine.
A savonius wind turbine is a drag type turbine; they are commonly used in cases of high reliability in many things. Savonius are excellent in areas of turbulent wind and self-starting.
Darrieus wind turbines are also known as eggbeater turbines because they look like a giant eggbeater.
As the starting torque of this turbine is very low, they require some external power source to start turning.
How does wind energy work to produce the electricity?
Till now, you might have a question, how does green energy work? So, let’s go further and see how wind energy is utilized to generate the electricity.
To create electricity from wind energy the wind turbines are used.
The shaft of the turbine is connected to a generator. The generator uses the turning motion of the shaft to rotate a rotor which has oppositely charge magnets and is surrounded by copper wire loops.
A rotor spinning inside of the core creates electromagnetic induction. This electromagnetic induction is used to produce electricity.
How Wind Turbines Work?
Wind turbines convert the kinetic energy in the wind into mechanical power. This mechanical power can be used for grinding grain or pumping water. A generator can convert this mechanical power into electricity.
Wind turbines operate on a simple principle.
The process of converting the wind power into mechanical energy starts with the turbine blades. There are two different types of blade designs, lift-type, and drag type.
Lift type is a common type of the modern horizontal axis wind turbine blade that you see at all the big wind farms.
As the air blows on both side of the blade, it takes the air long to travel across the leading edge. This creates a lower air pressure and higher air pressure on the trailing edge.
The difference in pressure, pull and push the blade around. Lift type blades have much higher rotational speeds hence they are well suited for generating electricity.
A drag type blade normally creates a slower rotational speed with a higher torque than a lift type design.
Drag type of wind turbine uses the force of the wind to push the blade. The wind is resisted by the blade and the wind’s force on it pushes it around.
This design has been used for centuries for milling, sawing, and pumping. A drag type wind turbine is not suitable for electricity on large scale.
The rotating blades are connected to a shaft which is connected to a generator. As blades start rotating because of wind power, it starts rotating the connected shaft. This central shaft, give rotational power to the generator, and the generator starts producing electricity. This is the simplest way to convert green energy into electricity.
Wind Turbine Parts and its Functions
You can transform green energy into electricity using wind turbines. The wind turbine is an assembly of some small and large parts. So, let’s move further for detail information on wind turbine parts.
Wind Turbine Blades
Most wind turbines have either two or three blades. A curved blade has a curved surface on top. They are very similar to a long airplane wing.
Wind turbine blades work by generating lift due to their curved shape.
Flat blades are cheap and easy to make but have high drag forces making them slow and inefficient.
A wind turbines rotor blade length determines how much wind power can be captured.
Wind Turbine Gearbox
The gearbox is a heavy and costly part of the wind turbine. It increases rotational speed from a low-speed rotor to a higher speed electrical generator.
Wind Turbine Tower
It is made from tubular steel or steel lattice. The tower supports the structure of the turbine. So, taller towers enable turbines to capture more energy and generate more electricity.
The rotor is connected to the main shaft, which spins a generator to create electricity. The gearbox is placed at the other end of the main shaft.
A wind turbines main shaft requires a reliable bearing for operation.
A generator is a pretty simple device. It uses the properties of electromagnetic induction to produce electrical voltage. So generating voltage is in effect generating current.
When the rotor spins the shaft, the shaft spins the assembly of magnets, generating a voltage in the coil of wire.
That voltage drives electrical current out through power lines for distribution.
Measures the wind speed and transmits wind speed data to the controller.
Wind Turbine Brake
It stops the rotor mechanically, electrically, or hydraulically, in emergencies.
To ensure the wind turbine is producing the maximal amount of electric energy at all times, the yaw drive is used to keep the rotor facing into the wind as the wind direction changes.
Starts up the machine at wind speeds of about 8 to 16 miles per hour (mph) and shuts off the machine at about 55 mph.
Wind Farm to Capture Electricity from Green Energy
When it comes to producing huge electricity from green energy sources, a wind farm is an ultimate choice. A Wind Farm or wind power plant is a group of wind turbines in the same location used to produce electricity.
Depending upon the requirement of electricity, a wind farm may consist of several hundred individual wind turbines.
As a general rule, to set up a wind farm, the wind speed must be above 16 km/hour. An ideal location would have a near constant flow of non-turbulent wind throughout the year. Local electricity demand or transmission capacity should also be taken into consideration while setting up the wind farm.
In general, a distance of 7 × Rotor Diameter of the Wind Turbine is set between each turbine in a fully developed wind farm.
Individual wind turbines are interconnected with a medium voltage (usually 34.5 kV) power collection system and communications network.
At a substation, this medium-voltage electric current is increased in voltage with a transformer for connection to the high voltage transmission system.
Construction of a land-based wind farm requires an installation of the collector system and substation, and possibly access roads to each turbine site.
A difference of 30m could potentially double the output, hence the exact position of each turbine is very important.
The world’s first wind farm was 0.6 MW, consisting of 20 wind turbines rated at 30 kilowatts each, installed at New Hampshire in December 1980.
Gansu Wind Farm in China is the largest wind farm in the world. It has a goal of 20,000 MW electricity by 2020.
A wind farm can also be located offshore. 630 MW London Array in the UK is the largest offshore wind farm in the world.
Advantages of Wind Power
- The wind is the free source of green energy. With modern technology, it can be captured efficiently to produce clean electricity.
- This form of green energy does not produce greenhouse gases or other pollutants.
- The land in between wind turbines can be used for agricultural or any other useful activity.
- Remote areas that are not connected to the electric power grid can use wind turbines to produce their own power.
- Wind power has a huge potential for the job market.
Disadvantages of Wind Power
- Wind turbines are noisy.
- The wind turbines do not produce the same amount of electricity all the time.
- Installation cost of a wind farm to produce the electricity is much more compared with other green energy sources.
Besides this information, you are suggested to read something more from below engineering books
To get the more details about the topic, I further recommended reading
- Wind Energy Basics: A Guide to Home and Community-Scale Wind Systems
- The Wind Energy: Theory and Practice
- Wind Power Basics
- Wind Energy Engineering
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