More than 900 years ago, medieval Europe became the first large civilization not to be run by human muscle power. Thousands and thousands of windmills and waterwheels, backed up by animal power, transformed industry and society radically. It was an industrial revolution entirely powered by renewable energy – something that we can (and do) only dream of today. Wind and water powered mills were in essence the first real factories in human history. They consisted of a building, a power source, machinery and employees, and out of them came a product.
A windmill is a structure or machine that converts wind into usable energy through the rotation of a wheel made up of adjustable blades. Traditionally, the energy generated by a windmill has been used to grind grain into flour. Windmills are designed by skilled craftsmen and can be constructed on site using hand tools. Windmills developed steadily over the centuries and achieved their most prominence in Europe during the eighteenth century. They were largely replaced as a power generating structure when steam power was harnessed during the nineteenth century. Today, windmill technology is experiencing a renaissance and the wind turbine promises to be an important alternative to fossil fuels in the future.
The earliest use was most likely as a power source for sail boats, propelling them across the water. The exact date that people constructed windmills specifically for doing work is unknown, but the first recorded windmill design originated in Persia around A.D. 500-900. This machine was originally used for pumping water then it was adapted for grinding grain. It had vertical sails made from bundles of lightweight wood attached to a vertical shaft by horizontal struts. The design, known as the panemone, is one of the least efficient windmill structures invented. It should be noted that windmills may have been used in China over 2,000 years ago making it the actual birthplace for vertical-axis windmills. However, the earliest recorded use found by archeologists in China is A.D. 1219.
The European windmills may have been influenced by the water wheels that had a horizontal axis. The water wheel had been known in Europe for long before this. Also, the horizontal axis design was more efficient and worked better. In general, these mills had four blades mounted on a central post. They had a cog and ring gear that translated the horizontal motion of the central shaft into vertical motion for the grindstone or wheel which would then be used for pumping water or grinding grain.
Initially, the only applications of windmills were the grinding of grain and (to a lesser extent) the pumping of water and the draining of lowland areas (for which they were connected to a waterwheel working in reverse – the scoopwheel - or to an Archimedean screw). Bread and oats were the staple diet of the Middle Ages (meat, fish and vegetables were only available to the rich) and all that grain had to be crushed or ground. It took one person with a hand mill two hours a day to grind enough flour for an average family. This “real-world” application of grinding of grain remained the most important use of windmills - as late as 1900, the entire wheat harvest of Northern Europe was ground by windmills in the Netherlands, Denmark and Germany.
Besides food production, two other major applications of windmill technology were the production of paper (using ropes and sails from ships as a raw material) and the sawing of wood. Windmills were also crushing chalk (to make cement), grinding mortar, draining mines, ventilating mineshafts (and even a prison), polishing glass and making gunpowder.
Textiles were another industry in which wind power came to the rescue: windmills were crushing seeds from flax (to make linen), preparing hemp fibers (to produce ropes and sailcloth), fulling cloth (to create soft wool), making paint and tanning and dying animal skins.
Not all regions were suited for watermills. The reasons could be that they did not have sufficient water resources (like Spain), that they were too flat and their rivers did not have enough flow (like the Netherlands and the downlands of England) or that rivers generally froze during winter (like in Scandinavia, Russia and parts of Germany). In these countries, windmills appeared in the 13th century, possibly earlier, and spread fast. Later, also regions that had abundant water resources constructed windmills, to relieve the pressure on rivers and streams.
The decline of the windmill was slow, especially in the Netherlands - the Dutch even preferred windmills with auxiliary steam engines over fully steam powered mills. More than 6 million wind powered water pumps (with annular sails) would be built in the United States between the 1850s and the 1930s, but elsewhere few windmills were erected after 1900. The attention shifted to wind turbines generating electricity, and that has remained so ever since.
Windmills have changed little over the last hundred years. In fact, one basic design conceived in the 1870s is still sold today. The major improvements have come in the types of materials used in construction. This trend will likely continue in future windmill products. However, the future of harnessing wind power is not in traditional windmills at all. The United States government has spent millions of dollars researching and developing wind turbines for electricity generation. In California, numerous wind farms are already in operation. Various other states and cities have plans for creating similar wind farms. In the future, wind power promises to be an environmentally friendly substitute for fossil fuels.
These days, wind turbines are turned into the wind automatically by means of electronic equipment. When the wind becomes too strong, the electronics turn the blades out of the wind so they are not blown to smithereens. Medieval millwrights had no microchips and so they had to find another solution. A wind turbine is a windmill-like structure specifically developed to generate electricity. They can be seen as the next step in the development of the windmill. 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)
As the 21st century began, rising concerns over energy security, global warming, and eventual fossil fuel depletion led to an expansion of interest in all available forms of renewable energy. Worldwide, many thousands of wind turbines are now operating, with a total nameplate capacity of 194,400 MW. Europe accounted for 48% of the total in 2009.
Education for Wind Turbine Technicians
According to AWEA (American Wind Energy Association), an estimated 85,000 Americans are currently employed in the wind power industry and related fields. Many workers are found on wind farms, which are frequently located in the Midwest, Southwest, and Northeast regions of the United States. Texas, Iowa, and California are the leading States in wind power generating capacity, but many other States—including Illinois, Indiana, Oregon, and Washington—are in the process of substantially increasing their wind-generating capacity.
Most windtechs learn their trade by attending technical schools or community colleges, where they typically complete certificates in wind energy technology, although some workers choose to earn an associate's degree. Many technical schools have onsite wind turbines that students can work on as part of their studies. In addition to lab coursework, other areas of focus that reflect the various skill sets needed to do the job include the following:
•Rescue, safety, first aid, and CPR training
•Mechanical systems, including blade inspection and
•Computers and programmable logic control systems
In addition to their coursework, windtechs typically receive more than 12 months of on-the-job training related to the specific wind turbines they will maintain and service. Part of this training is manufacturer training. Other training may include an internship with a wind turbine servicing contractor. Although not mandatory, professional certification can demonstrate a basic level of knowledge and competence. Some employers prefer to hire workers who are already certified in subjects such as workplace electrical safety, tower climbing, and self-rescue. There are many organizations who offer certifications in each of these subjects, and some certificate and degree programs include these certifications. Windtechs, are projected to grow 96% over the next ten years, much faster than the average for all