Wind Power and Wind Turbines

Wind Turbines

Wind turbines rotate when hit by wind at almost any speed. The blades of most turbines will begin to turn at a wind speed of 3-5 meters per second, which is a gentle breeze. The spinning motion of the turbine is what turns a shaft in the nacelle – which is a box-like structure at the top of a wind turbine. There is a generator that is built into the nacelle which turns the kinetic energy of the turning shaft into electrical energy. This then passes through a transformer, which steps up the voltage so it can be transported on the National Grid or used by a local site ("How do wind turbines work?," 2019). Wind power converts into electricity by magnets moving past the stator which are stationary coils of wire. As the magnets pass the stator, AC electricity production occurs. It is then converted into DC electricity ("How a Wind Turbine works: Wind Power: Renewable Energy," n.d.).

(Parts of a wind turbine, n.d.)

One of the earliest devices to harness the power of the wind was the windmill, which was used to pump water and grind grain. A more modern version of the windmill is the wind turbine which also uses propeller - like blades to catch the wind. There are also a number of generators in development that will be used to harness high altitude winds. There are two types of wind turbines; vertical axis and horizontal axis. Some turbines are usually located on lands that receive high altitude winds and the others are located off shore, positioned to catch the wind that runs across lakes and seas. The current generators that are in development will catch the wind in the upper atmosphere and relay the information back to earth via long cables. Vertical axis turbines use a series of rotor blades that rotate around a central axis. Horizontal axis turbines have blades arranged in the shape of a propeller, a similar design to windmills ("Devices Used to Harness Wind Energy," n.d.).

Off shore wind turbines

(offshore wind turbines, n.d.)

Vertical

Horizontal

Vertical & Horizontal axis turbines

(Wind turbine comparison (vertical vs. Horizontal), n.d.)

Wind mill     (Wind mill, n.d.)

Wind turbines transform the kinetic energy of the wind into electrical energy. The steps involved are:   

• Step 1: Moving air pushes against the blades of the turbine, making them rotate. During this process, some of the kinetic energy of the moving air is converted to the mechanical energy of the spinning blades.
• Step 2: The shafts and gears inside the gear box transfer the mechanical energy of the turbine to the generator ("Wind Energy Theory," 2019).

                       (energy transformations that take place in a wind turbine, n.d.)

The amount of electrical power that is produced by a wind turbine not only depends on the speed of the wind, but also how the turbine is built:

• The number of blades                            
• The gears used
• The type of generator used
• The computer system that controls the operation of the turbine and its power output
• The length of the blades
• The shape of the blades
• The weight of the blades                                                  
• The angle of the blades to the wind
• The height of the tower                              

  ("Wind Energy Theory," 2019)

Wind turbines do not always produce electricity. Although the wind may be available, it is not always strong enough to operate the wind turbine at full capacity. A good location for a wind turbine might have a 35% capacity factor. This means that the turbine will produce 35% of its capacity on average over a year. Apart from the wasted energy such as mechanical energy, heat energy and sound energy, wind turbines are quite efficient ("Wind Energy Theory," 2019).

You can install wind turbines on properties, boats or caravans. The average wind speed needs to be above 18 km/h to make installing a wind turbine worthwhile. The most ideal locations for wind turbines are: In the country, on farms or on the coast. The more buildings that surround the installation of the turbine, the less wind there will be ("How a Wind Turbine works: Wind Power: Renewable Energy," n.d.). Wind turbines are commonly located on hilltops or near the ocean. In some countries, turbines have been built in the ocean, either floating on the surface or being extended to the sea floor through giant pylons ("Wind energy," n.d.).

Ocean wind farm

(How are ocean wind farms made?, n.d.)

Hilltop Wind turbines

(Wind turbines on a hilltop, n.d.)

Wind turbines are currently the cheapest source of renewable energy. They generate electricity through the naturally occurring power of the wind. They are renewable resources because wind is  constantly being replaced at the same rate that it is being used meaning that this natural resource will not run out ("Wind," 2018). Wind is generated by the uneven heating of the earth’s atmosphere and surface by the sun. When air is heated, it rises and cooler air flows into the void, creating wind. As long as the sun shines, wind will blow, making it a reliable source of renewable energy ("Pros & Cons of Wind Energy to Solve Global Warming," n.d.).

(How is wind created?, n.d.)

In 2018, Australia’s wind farms produced 33.5% of the country’s clean energy and supplied 7.1% of Australia’s overall electricity. Over 850 MW of wind energy was installed in 2018, making it the best year for installed wind farm capacity ("Wind," 2018).

Wind energy is one of Australia’s main sources of renewable energy. At the end of 2018, there were 94 operating wind farms across Australia. Wind has been an established part of electricity generation in Australia for many years ("Wind energy," n.d.). Cooper’s gap wind farm, in Queensland, will be the largest operating wind farm in Australia once completed at the end of this financial year. This wind farm is located in the darling downs region to the north-west of Brisbane. It began generating in June and currently has 50 turbines which is nearly half of the 123 turbines planned for the facility ("AGL shows off what will be Australia’s largest wind farm," 2019). There are 10 main wind farms in New South Wales, 10 in Victoria, 7 in Queensland, 10 in South Australia, 10 in Western Australia and 4 in Tasmania ("Wind Farms in Australia | State-by-State Guide ? Canstar Blue," 2019).

(Coopers gap wind farm, n.d.)

Wind turbines are used all around the world for generating electricity as a large scale renewable energy resource. The top 10 countries that have the highest wind capacity in the world are China, Germany, India, Spain, United Kingdom, France, Brazil, Canada and Italy. China is the world leader in the production of wind energy, with an installed capacity of 221 GW. Germany has the highest installed wind capacity in Europe with 59.3 GW. India has the second highest wind capacity in Asia with a total capacity of 35 GW. Spain has the fifth highest installed capacity at 23 GW. The United Kingdom is the third European country on the list with a total capacity of 20.7 GW. France is seventh on the list with a capacity of 15.3 GW, followed by Brazil which has the largest wind capacity in South America with 14.5 GW. Canada’s renewable energy capacity stands at 12.8 GW and Italy has reached just over 10 GW in wind energy capacity ("Wind energy by country: Top 10 in the world ranked by capacity," 2019). Not all countries use wind turbines to generate electricity because countries such as Iceland do not have much wind, meaning that wind power is hard to come by and installing a wind farm would not be worthwhile (Daniel Van Boom, 2018).

Wind energy offers many advantages, which explains why it is one of the fastest growing energy sources in the world. These advantages include that:

• Wind power is cost effective
• It can support more than 600,000 jobs in manufacturing, installation and maintenance
• They do not pollute the air like power plants such as coal or natural gas do
• It is a domestic source of energy as wind supply is abundant and never ending

("Advantages and Challenges of Wind Energy," n.d.).

• They are a renewable energy resource
• They do not emit greenhouse gases or any other forms of pollution
• They are more energy efficient than most power stations that burn fossil fuels
• They are cheaper to run compared to other energy resources
• They can be established in remote areas where other energy resources cannot be used

("Wind Energy Theory," 2019).

Wind power is a clean energy source that we can rely on for the long-term future. One wind turbine can be sufficient enough to generate energy for an entire household ("How a Wind Turbine works: Wind Power: Renewable Energy," n.d.). Wind power has the potential to reduce global warming. The electricity generated by wind in the United States in 2012 avoided the release off 79.9 million metric tons of carbon dioxide into the atmosphere, which is the equivalent to 14 million cars off the road. The conversion of wind energy to electricity does not contribute to global warming at all ("Pros & Cons of Wind Energy to Solve Global Warming," n.d.).

(Green vs. Coal, n.d.)

Wind energy workers are exposed to many hazards can that result in death and serious injuries. Many incidents involve falling, severe burns from electrical shocks and crushing injuries ("Green Job Hazards: Wind Energy," n.d.). People who live near wind turbines describe the flickering effect caused by the shadows cast by the wind turbines, the audible sounds and the sub audible sound pressure levels as annoying. They claim that the turbines negatively impact their quality of life ("Does living near wind turbines negatively impact human health?," 2018). Some residents report symptoms such as:

• Nausea
• Sleep disorders
• Fatigue 
• Increased stress as a result of living near wind turbines

("Can Wind Turbines Make You Sick?," n.d.).

The top 5 hazards associated with wind turbines are:

• Falling
• Confined spaces inside the turbine
• Electrocution
• Fires
• Moving parts

("Wind Turbine safety – Top 5 Hazards," 2019).

There are many environmental concerns associated with wind turbines including the potential to reduce habitat for wild life, fish and plants and the fact that the spinning turbine blades can pose a huge threat to flying wildlife such as birds and bats ("Environmental Impacts and Siting of Wind Projects," n.d.). Modern wind turbines can be very large machines, affecting the visual look of the landscape. Some wind turbines have caught fire, whilst other have leaked oily fluids. They can contribute the decline in populations of flying wildlife. They can use rare earth minerals, where the mining of these minerals can have a negative effect on the environment. Producing metals and other material that are used in the construction of wind turbines require energy that has been produced by fossil fuels ("Wind energy and the environment," 2018).

(effect of wind turbines on wildlife, n.d.)

Wind power continues to be one of the most promising renewable energy resources. Over the last decade, wind farms have popped up all over the world and the wind industry has seen a huge growth. It has been indicated that we will be seeing a lot more wind turbines in the future, in many more regions across the globe. It stands to reason that in regions with vast potential for clean power generation, wind farms are almost certain to take root. The future will be filled with wind turbines as they are growing larger and more efficient ("In the future, will wind turbines be everywhere?," 2012).

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