The History of Wind Energy
Since early recorded history, people have recognized the opportunities presented by this natural resource, and have been harnessing the energy of the wind. Wind energy was the "fuel" for ancient sailing ships on the ocean and propelled watercraft along the Nile river as early as 5000 B.C. By 200 B.C., simplistic windmills were used to pump water in China, while vertical-axis windmills with woven reed sails were grinding grain in Persia and the Middle East.
New ways of using the energy of the wind eventually spread around the world. By the 11th century, people in the Middle East were using windmills extensively for food production; returning merchants and crusaders carried this idea back to Europe. The Dutch refined the windmill and adapted it for draining lakes and marshes in the Rhine River Delta. In Denmark by the year 1900 there were about 2500 windmills for mechanical loads such as pumps and mills, producing an estimated combined peak power of about 30 MW. When settlers took this technology to the New World in the late 19th century, they began using windmills to pump water for farms and ranches, and later, to generate electricity for homes and industry. In the American midwest between 1850 and 1900 an estimated six million small windmills were installed on farms to operate irrigation pumps.
By the 1930s windmills were widely used to generate electricity on farms in the United States where distribution systems had not yet been installed. Used to replenish battery storage banks, these machines typically had generating capacities of a few hundred watts to several kilowatts. Beside providing farm power, they were also used for isolated applications such as electrifying bridge structures to prevent corrosion. The most widely-used small wind generator produced for American farms in the 1930s was a two-bladed horizontal-axis machine manufactured by the Wincharger Corporation. It's blade speed was regulated by curved air brakes near the hub that deployed at excessive rotational velocities, and it produced a peak energy output of 200 watts. These machines were still being manufactured in the United States as recently as the 1980s.
Industrialization both overseas and following shortly thereafter in the United States, combined with the increasingly widespread use of the steam engine, led to a gradual decline in the use of windmills. In the 1930s, the "Rural Electrification Administration's" programs brought inexpensive electric power to many rural areas in the United States. The industrialization movement was also a catalyst for the development of larger windmills to generate electricity, commonly called wind turbines. In the 1940s the largest wind turbine of the time began operating on a Vermont hilltop known as "Grandpa's Knob". This turbine, which generated approximately 1.25 megawatts in winds of about 30 mph, fed electric power to the local utility network for several months during World War II.
Not surprisingly, the popularity of utilizing wind energy has maintained a correlation to the current price of fossil fuels. When fuel prices fell after World War II, interest in wind turbines lagged. But when the price of oil skyrocketed in the 1970s, so did worldwide interest in wind turbine generators. Research and development of wind turbine technology following the oil embargo(s) of the 1970s resurrected previous ideas and introduced new ways of converting wind energy into useful power. Many of these approaches have been demonstrated in "wind farms" or wind power plants — groups of turbines that feed electricity into the utility grid — in the United States and Europe.
Modern windmills are very different to their old fashioned relations, which were large stone or brick buildings using wooden sails today the sails of a windmill are made from light alloys and are very aerodynamic.
As the 21st century dawned, fossil fuel was still relatively cheap, but rising concerns over energy security, global warming, and fossil fuel depletion led to renewed interest in all available forms of clean, green energy. The commercial wind power industry began expanding at a robust growth rate of about 30% per year, stimulated by the broader availability of wind resources, and falling production costs attributable to advancing technology and wind farm management. The steady run-up in oil prices after 2003 led to increasing fears that peak oil was imminent, further increasing interest in commercial wind power. Even though wind power generates electricity rather than liquid fuels, and thus is not an immediate substitute for petroleum in most applications (especially transport), and fears over potential fossil fuel shortages only added to the urgency to expand wind power. Earlier oil shortage concerns had already caused many utility and industrial users of petroleum to shift to coal or natural gas. Natural gas began having its own supply problems, and wind power showed potential for replacing natural gas in electricity generation.
How will history look back at where we are now, in 2008? Right now, growth of wind energy is being driven by the commitment from many industrialized nations, including the United States, to reduce greenhouse gases. The cost of wind energy has gradually fallen, as technology has improved. The annual wind energy that could potentially be supplied is equal to 20 billion barrels of oil per year. Unlike oil fields, wind energy is a renewable, clean, green resource. We can only hope history reflects that the industrialized world embraced this free, inexhaustible renewable resource to it's full potential.