Windmills use wind power to pump water, grind grain, and generate electricity - an ancient technology people have been harnessing for millennia.
The windmills of the 19th century replaced steam engines for farm power because they could be built anywhere with access to fresh air. These windmills atop wooden, iron, or steel towers were found throughout North America.
Today, wind turbines are becoming bigger and more complex, with taller towers and longer blades, as they are aimed at producing more energy.
Origin
Windmills are machines that harness the wind's power to do work, such as grinding grain into flour or pumping water. A windmill consists of three main parts: a tower with sails, a rotating body (millstones or pump), and a stationary wheel/gears. Windmills have been in use for thousands of years, marking one of humanity's oldest examples of human creativity as well as one of its most efficient machines ever devised.
Windmills' precise roots remain unclear, although archeological evidence points towards their use for more than 2,000 years in ancient China. Their invention likely resulted from two separate developments: wind power and the technique for grinding grain between stones to make flour. The first windmills were likely designed purely as devices to harvest wind power to grind grain and pump water; when these proved successful other uses surfaced for this device.
Early windmills were vertical, with sails attached to a central shaft connected by an axle for driving millstones or pumps. These early windmills provided a cost-cutting alternative to more costly waterwheels; typically located near water sources like streams or rivers to take advantage of its flow; they could even be found in desert regions.
Later, England and France saw the development of smock windmills. These windmills were designed to be more flexible than their post mill counterparts, allowing sails to be adjusted according to wind direction for maximum effectiveness. Taller than traditional post mills, smock windmills could even operate effectively in low winds.
Another design innovation was the rotary or fan mill, which enabled sails to turn automatically with the wind direction, enabling a single person to operate it without constant adjustment. A later improvement included using hinged shutters and chains as part of a self-regulating system to automatically luff sails when wind conditions change.
Steel windmills became more widely popular during the nineteenth century. These machines could operate under lower wind speeds and required less maintenance than earlier models; as a result, they helped transform millions of acres into productive farms while even providing running water in homes. When steam power became popular, however, these elegant structures gradually fell out of favor but many can still be found today as a testament to human ingenuity.
Function
Windmills' primary function is to convert wind energy into other forms, typically electricity. They're also useful for turning grain into flour or pumping water - something most mills don't do efficiently enough. Horizontal and vertical-axis mills exist, with horizontal-axis models having sails that collect wind from multiple directions, moving the sails in turn causing a shaft to rotate which connects either directly to a millstone or more recently turbines, an electric generator to produce energy for electricity production.
Windmills have long been used to produce mechanical energy without necessarily using electricity; from grinding grain, power saws, pulp wood for paper production and other tasks that require mechanical force but not necessarily electricity. King Hammurabi referenced windmills for mechanical energy generation in his codex (reign 1792-1750 BC). Iran, Afghanistan, and Pakistan saw their first windmills appear sometime during the 9th century.
With an expanding global population and agricultural production increasing exponentially, people needed more and more energy for daily living needs - wind-powered devices were essential in providing both food and electricity production - by the 1920s there were over six million mechanical windmills operating worldwide!
Later on, windmill use began to diminish due to cheaper oil and coal alternatives; however, with the Oil Crisis of the 1970s coinciding with an emerging environmental movement, people once more began favoring renewable sources of energy, including wind power.
At this time, large-scale wind farms began being established. Windmills were often installed miles offshore where winds tend to be stronger; this location is chosen in order to maximize energy production. Windmills that generate electricity through rotors consist of three or more blades mounted on a hub which are connected directly to a main shaft which connects with an electricity generator for the production of energy.
One major concern surrounding renewable energy sources such as wind turbines is their effect on migrating birds and bats, particularly birds with long, curved wings such as bats. Concerns exist that wind turbines' longer blades could cause collisions between bird or bat species and the structure or with each other - though proper siting of wind farms can reduce collision risks considerably.
Benefits
Wind energy provides an environmentally-friendly alternative to fossil fuels with minimal environmental impacts. Furthermore, it's a renewable resource - unlike traditional energy sources like natural gas which need replacing regularly. Furthermore, wind power can be relatively economical than other forms of power.
Windmills are flexible machines that can be tailored to a range of uses, from grinding grains and pumping water, to producing electricity and creating income for their owners. Windmills can even generate substantial returns that can fund energy-saving measures and local projects.
Windmills have been around for 3700 years, evidence of early ones found in Persia and along the Mediterranean coast dating back as far. Modern windmills are created through advances in design and construction techniques; these allow larger sails, more machinery ancillaries, as well as increasing surface area available for power production.
Windmill blades can also be adjusted to match different weather conditions. Longer blades generate more power - similar to how a bike chainring can be expanded for greater speed and power output.
Windmills may provide many advantages, but in the long run, they cannot replace the Ogallala Aquifer (a massive subterranean reservoir located across several states that is being depleted faster than it can be replenished), leading to land conversion to agriculture and desertification.
Future trends suggest that wind energy could move away from large-scale turbines towards small community-owned wind turbines, providing communities with income from their projects while protecting local landscapes and protecting the environment.
Costs
Windmills are structures that convert wind energy into rotational energy, known as windmills. A windmill typically consists of multiple blades connected to a box called the nacelle with an integral shaft. When exposed to any form of breeze, these blades begin to move, creating kinetic energy which in turn turns a generator and produces electricity. They're typically situated 100 feet or higher above ground to take advantage of higher winds.
As demand for renewable energy continues to increase, costs associated with building and operating wind farms have become less costly; however, initial investments still represent a substantial initial expense. There are ways of mitigating this cost; local authorities could use money received from commercial wind power projects for investment into other energy-saving and renewable energy initiatives.
Step one in building a windmill involves selecting an appropriate location. This requires selecting an open site with good access to wind and no obstructions. Next, either a dirt mound or concrete base must be built so as to raise it above the ground and capture more wind.
Windmills can be used for grinding grain, powering saws, or pumping water - in the past Dutch engineers and farmers relied on windmills as drainage for low-lying areas known as polders to expand arable land - while in today's era, they're mostly employed to generate electricity.
Windmill blades must be long to maximize energy from the wind; longer blades provide more surface area upon which to exert force and higher rotational speeds, thus producing maximum output from its energy sources.
Windmills only produce electricity if the wind blows at an ideal speed and direction, so for optimal electricity generation, a wind farm must be constructed in an area with consistent wind speeds of at least 8 meters per second and taking climate change into consideration when selecting its location is essential.