The Difference Between Windmills and Wind Energy
It's common to hear the terms windmills and wind energy mentioned in conversation today. Many people refer to the big towers topped with wind turbines as a windmill because it's the only other concept we have of using wind energy.
Windmills and wind energy installation have big propeller blades in common and both are meant to harness the wind blowing around the blades and turn the wind into usable energy.
Windmills
Human beings have been looking for a way to use wind energy for centuries. Ancient versions were windwheels used for various purposes from the 4th century. By the 17th century, windwheels were being building in an attempt to provide wind powered irrigation.
The first windwheels were horizontal wheels that rotated around a vertical axis. Their invention is credited to Persia in the 9th century but there is some argument as development of windmills was widespread.
The earliest horizontal versions had six to twelve sails and were used to grind grain or draw water from wells. The Industrial Revolution led to the same horizontal type windwheels in Europe for a time. Very few were built but these were the first examples of windmills in modern times.
The vertical windmill design development in European countries. The purpose of the structures was to grind grain. The earliest version was called the post mill as the main part of the windmill was balanced on large upright post. This allowed the moving wheel to rotate to face the changing direction of the wind.
Next came the hollow-post mill where the mounting post was hollow and a drive shaft could be used down the interior of the post. This was a common element of the landscape in the Netherlands for centuries where the hollow-post mills were outfitted with scoop wheels to drain wetlands.
An expanding European economy led to larger and more table sources of power. Thus the tower mill was build where the windmill and wheel are fixed in direction with a cap that can be turned into the wind.
This fixed structure allowed much larger and taller windmills to be built. Later, smock mills became commonly seen throughout Europe and may be the design that comes to mind when you think of windmills and wind energy.
The large sails of a windmill are used to catch the wind energy and transmit it to a grist wheel or other mechanical component. Milling grain was the most common goal of building windmills but they were also used for drainage and to provide power for other processes like threshing, processing wool and paper mills.
At the peak of popularity, there were about 200,000 windmills in Europe. During the same period water produced energy that used water to power a wheel was more popular than windmills.
The introduction of the steam driven engine and the internal combustion engine led to the decline of the windmill as a power source. In the 1800s there were 10,000 windmills gracing the landscape of the Netherlands but today only about 1000 are still standing.
Wind Turbine
The wind turbine is what we think of in the U.S. when someone refers to a "new windmill". Windmills and wind energy are used in a different way through a wind turbine but are capturing the kinetic energy from the wind just as the bulky windmills did for centuries.
A wind turbine converts the wind to electricity. The first wind turbines were built over one hundred years ago and by the 1930s windmills were often used in the U.S. to generate electrical power. This provided electricity to areas of the country where the power grid had not yet expanded.
The ability to power homes with electricity was a modern marvel and power grids were quickly established in cities across the country. For smaller communities in less populated areas it took years for the power lines to spread over the land.
Wind turbines were used to create electricity for local areas and even the less than perfect designs of the time showed promise for power generation. The demand for electric power was immediate and grew rapidly.
Fossil fuels were readily available and inexpensive and for many years the concept of using wind turbines to generate electricity were confined to isolated areas where power was unavailable or unreliable.
Rising concerns over use of fossil fuels in the 21st century were based on the pollution they release when processed and used, on the damage to the environment in mining those fuels and on the possibility the fossil fuels might be used up in the near future.
New restrictions to maintain the land and provide some level of safety for the environment combined to greatly increase the cost of electricity for all of us. Not surprisingly, many engineers turned a fresh eye on windmills and wind energy and the results are impressive.
Awkward windmills and short wind towers have been replaced with tall, birdlike towers topped with long, slender propels and huge wind turbines. With dozens of these new style windmill and wind energy turbines placed in wide open spaces as wind farms, you could say we are beginning to grow our own electricity.
