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Wind Power

Wind Energy- in the winds of change we will find our true direction

Wind Energy

In layman’s terms, moving air is called wind. The wind has always been there since the existence of air on earth and humans have been feeling its power all along in form of storms. The wind is formed by the uneven heating of the earth’s surface by the sun. The reason behind this uneven heating is the multifariousness of the earth’s surface which is made up of various land and water formations that absorb the sun’s radiation unevenly. The part of the earth’s surface that receives direct sunlight or the part that absorbs maximum heat gets warmer than the one that receives indirect sunlight. Along with the earth’s surface, the air surrounding it gets warm too. The warmer air is lighter than the colder air and starts rising, making air pressure low at that area, while the colder one starts moving from the high-pressure area towards the low-pressure zone, left by warmer air, to fill it. This movement of air results in formation of wind. The speed is determined by the rate of air pressure change, or gradient, between the two pressure areas. The greater the pressure difference, the faster the winds.

Humans started harnessing wind energy as early as 5000 BC, using it to propel sailboats to navigate the Nile and later the Mediterranean. The earliest representation of a ship under sail on a painted disc found in Kuwait, dating between 5500-5000 BC, suggests that the Egyptians were the first builders of sailing ships, thus becoming the first people to harness wind energy. The earliest known wind-powered grain mills and water pumps were used by the Persians in A.D. 500-900. The first windmills, as recorded by Persian geographer Estakhri in the 9th century- being operated in Khorasan (Eastern Iran and Western Afghanistan), were panemone windmills, made of six to 12 sails covered in reed matting or cloth material that used to rotate around a vertical axis, around a horizontal plane. These are also known as horizontal windmills. The vertical windmills were developed in the 12th century in north-western Europe. The earliest of the vertical windmills were called ‘post mills’ because their structure was balanced on a large upright post, enabling it to rotate to face the wind direction. By the end of the 13th century, the masonry tower mill, on which only the cap is rotated rather than the whole body of the mill, had been introduced. These mills were better than their predecessor because unlike post mills, only the cap of the tower mill turned into the wind, which allowed the main structure to be made much taller. With a tall structure the sails were made longer, enabling them to provide useful work even in low winds.

These windmills reached their peak in 1850 when the total number of windmills is estimated to have been around 200,000 in Europe. The wind turbine was a major development in wind-powered technologies. A wind turbine is a windmill-like structure, designed to generate electricity. The rotation of the blades of a wind turbine further spins the rotor. The rotor connected to the generator, either directly or through a shaft, and a series of gears that speed up the rotation, rotate it, generating electricity. The first wind turbines were built by the end of the nineteenth century by Prof James Blyth in Scotland (1887), Charles F. Brush in Cleveland, Ohio (1887–1888), and Poul la Cour in Denmark (1890s). Poul la Cour’s turbine’s diameter was 17 meters (50 feet), it had 144 rotor blades made of cedarwood, and it generated about 12 kilowatts (kW) of power, and it later became the local powerplant of the village named Askov.

Although, industrial revolution and first use of coal came as a hindrance for wind energy and its use declined again by 1930s, but 1970s energy crisis due to fossil fuel shortage made the world shift to alternative energy sources, like wind and water. Today, along with other renewable sources of energy, wind energy has reached new heights. Global installed wind-generation capacity onshore and offshore has increased by a factor of almost 75 in the past two decades, jumping from 7.5 gigawatts (GW) in 1997 to some 564 GW by 2018. In 2019, wind supplied 1430 TWh of electricity, which was 5.3% of worldwide electrical generation, with the global installed wind power capacity reaching more than 651 GW. According to World Wind Energy Association, this capacity reached to 710 GW in 2020. There are over 380,000 wind turbines on the planet, with an average onshore wind turbine rated at 2.5 – 3 megawatts capable of producing 6 million kWh every year and a 3.6 MW offshore turbine producing double of that. As of 2020, the wind turbine efficiency leader is the large, three-blade, horizontal-axis design, which is why more than 300,000 have been deployed. The aerodynamic blades generate more electricity than any other design, both because the lift produced moves the blades faster, and each blade is moving through “clean” air.

China is the current world leader in wind energy with a installed capacity of 221 GW, over a third of the world’s capacity. It led the world’s biggest ever increase in wind power capacity as developers built almost 100GW worth of windfarms last year enough to power all the homes in United Kingdom. It also has the world’s largest onshore wind farm with a capacity of 7,965 megawatt. China is followed by US in second place- with 96.4 GW of installed capacity and Germany in third place- with 59.3 GW of installed capacity. India, with a capacity of 35 GW, has the fourth highest capacity in the world and second highest in Asia. It has the third- and fourth-largest onshore wind farms in the world — the 1,500-MW Muppandal wind farm in Tamil Nadu and the 1,064-MW Jaisalmer Wind Park in Rajasthan.

Wind energy, along with all other renewable energies, is expected to make 30 percent of world energy by 2024. With the world more concern about diminishing fossil fuels and environmental crisis, a shift to renewable sources of energy seems to be the only valid move. The DOE’s Wind Vision Report says that wind could potentially support more than 600,000 jobs by the year 2050 in manufacturing, installation, maintenance, and supporting services and help avoid 12.3 gigatonnes of greenhouse gases.

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