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MODERN ENERGY CONCEPTS WIND FARMS
But ideal areas for wind farms installation are generally near mountain sea or a river banks. Wind farms comprising propeller-type units have first started in Hawaii, California, and New Hampshire. Average electricity production capacities range of each wind turbine was in early days from 10 to 500 kilowatts per unit. During 1984 the total output of all U.S. wind farms exceeded 150 million kilowatt per hour. This was a great break through as this amount of electricity produced by the substantial, method of wind farms was a major chunk of the total electric power generated in the United States. Wind Power Efficiency Wind Mills are quite effective and suitable for the sustainable production of electricity for a house, for a street or a remote village or even an entire City. If a greater number of units are installed in a certain area. At a lower speed we need a greater number of high capacity wind turbines. An average Wind Farm can have an average 15-20 wind turbines installed but in some large wind farms in Europe they have installed thousand of wind turbines at a time for a high volume of electricity production. Wind Turbines Development
Adopting the ideas gained
from airfoil and aircraft propeller designs, windmill designers
and manufacturers began to replace broad windmill sails with a few
slender propeller-like blades. In 1931 the first propeller wind
turbine was erected in the Crimea. From the 1940s, experimental
twin-blade turbines were constructed in the United States and later
in Scotland and France. In The Netherlands a few old-fashioned mills
were adapted to generate electricity. Today, wind turbines for electric
power generation are most commonly used machines for the electricity
production all over the World. Latest Trends and Concepts
Modern wind turbines extract energy from the wind to produce electricity, by rotation of a propeller-like set of blades that drive a generator through appropriate shafts and gears. The older term windmill is often still used to describe this type of device, although electric power generation rather than milling has become the primary application. As was noted earlier, windmills, together with waterwheels, were widely used from the Middle Ages to the 19th century during the course of which they were supplanted by steam engines and steam turbines. Though they continued to be used for pumping water in rural areas, wind turbines practically disappeared in the 20th century as the internal-combustion engine and electricity provided more reliable and usually less expensive power. Interest in wind turbines for electricity generation was rekindled by the oil crisis of the mid-1970s. High initial costs, intermittent operation, and maintenance costs, however, have prevented wind turbines from becoming a significant factor in commercial power production. In the early part of this century, windmill production in the United States was in its prime. In 1900, half the market for windmills was supplied by the Aermotor Company in Chicago which claimed, at one point, to have 800,000 mills in service in the U.S. with more than half in operation for 40 years or more. In a time when electricity was not available in rural areas, windmills were ideal for pumping water, and producing electricity. In the late 1800's, when electricity was first being introduced as a viable power source, the high cost of rural electric transmission lines directed much effort into the design of windmills capable of producing electric power. In fact, the first electricity generating windmill in the U.S. was designed, in 1888, by Charles F. Brush in Cleveland, Ohio. With the development of extensive transmission line networks and a seemingly endless supply of cheap electricity from hydroelectric and fossil fuel burning power plants, the development of wind resources effectively came to a halt. However, the climate for wind energy is changing. Wind remains one of our most abundant and economical renewable resources, and technological advances in wind turbine design and rising fossil fuel costs should make wind a viable electrical generating alternative. Modern wind turbines bear little resemblance to the windmills that still dot the landscape in rural areas. With a few notable exceptions, such as the 1941 1.25 MW Smith Putnam wind turbine operated near Rutland, Vermont, the majority of wind turbines built before 1970 were small units designed for water pumping, and battery charging. Although a broad small windmill market still exists, modern, strong, lightweight materials have allowed development of very large, 300 kW to 1.5 MW, reliable, wind turbines which can generate and deliver, power directly to the electrical grid. Wind turbines today come in two basic forms, horizontal axis wind turbines (HAWTs), such as the Altamont Pass turbines, and vertical axis wind turbines (VAWTs), also called Darrieus turbines after their French inventor, G.M. Darrieus (and sometimes eggbeaters for obvious reasons). For a variety of reasons, most large wind turbines in production today are 3 bladed HAWTs. Modern, reliable (available 98% of the time) wind turbines are designed to use about 30% of the available wind energy. Theoretically, the amount of wind energy available in the United States is about 30 times the annual U.S. energy consumption. Of course, only a small part of this energy resource can be practically used, but the potential is still enormous. Worldwide wind power generation exceeded 13,400 megawatts in 1999, with a majority of recent sales going to Europe. Wind power can currently be produced for about 3 - 5 cents per kilowatt hour. The Department of Energy is supporting new developments in wind turbine technology.
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A wind farm is a group of wind
turbines erected next to each other in a location where there is
sufficient wind to turn the blades of wind turbines/wind mills.
The wind turbines are normally extremely light and easy to turn
even in the areas where there is little wind.
The development of the electric
generator aroused some interest in the wind as a "free"
power source. The first windmill to drive a generator was built
in 1890 by P. LaCour in Denmark, using patent sails and twin fantails
on a steel tower.
By 1940, single
turbine units with a power capacity of 100,000 kilowatts were common.
Ever-larger turbines (with higher efficiencies) have been constructed
during the last half of the century, largely because of the steadily
rising cost of fossil fuels. This required a substantial increase
in steam generator pressures and temperatures. Some units operating
with supercritical steam at pressures as high as 34,500 kilopascals
gauge and at temperatures of up to 650º C were built before
1970. Reheat turbines that operate at lower pressures (between 17,100
to 24,100 kilopascals gauge) and temperatures (540-565º C)
are now commonly installed to assure high reliability. Steam turbines
in nuclear power plants, which are still being constructed in a
number of countries outside of the United States, typically operate
at about 7,580 kilopascals gauge and at temperatures of up to 295º
C to accommodate the limitations of reactors. Turbines that exceed
one-million-kilowatt output require exceptionally large, highly
alloyed steel blades at the low pressure end. More efficient units
with a power capacity of more than 1.3 million kilowatts may eventually
be built.