Harris.Hoy.Fall.2009.energywiki

=Wind Power=



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 * __Introduction__**

The idea of wind power has been used for the last 5,000 to 6,000 years. It has been used for things such as propelling sailboats, irrigation pumping, and milling grain, all of which have grown and evolved with the changes in time. Even though the technology had changed tremendously, the basic concept of using wind to power things that we wish to use has not. The wind mill first started being used in sailing and milling grain, but as the threat of oil depletion started becoming an ever increasing threat the use of wind to power homes and business became more realistic. In July 1887, a Scottish academic by the name of Professor James Blyth began experimenting with the use of wind powered machine. By the winter of 1887 he was able to create such machines which could power his house and laboratory. Since then small wind units were used for lighting isolated rural buildings but it wasn’t until the late 1970’s that the modern wind power industry began. By 1980’s a Danish scientist and inventor Poul la Cour was able to use the electricity generated by the wind to produce hydrogen.

Wind power shows a general evolution from the use of simple, light devices driven by aerodynamic drag forces; to heavy, material-intensive drag devices; to the increased use of light, material-efficient aerodynamic lift devices in the modern era. The earliest known use of wind power is the sail boat, and this technology had an important impact on the later development of sail-type windmills. The first windmills were developed to automate the tasks of grain-grinding and water-pumping and the earliest-known design is the vertical axis system developed in Persia about 500-900 A.D. Grain grinding was the first documented wind mill application. The grinding stone was affixed to the same vertical shaft and was enclosed in a building, which also featured a wall or shield to block the incoming wind from slowing the side of the drag-type rotor that advanced toward the wind. Windmills were also used in China, which is often claimed as their birthplace.  

With the increase need for safe and efficient transportation of people and goods came the advent of the sail boat. The boat used wind to move the boat from place to place. This was a step up from the original row boats which at the time was the best means of water transportation but used manpower. Sail powered boats required fewer people to man them and were therefore more efficient for cargo purposes. Also, as in the case of a ship being used to transport troops, the troops wouldn’t be worn out from rowing everywhere, as the wind took care of that for them. Along with the use of boats came the use of mills to help with the harvesting of water and milling grain. The use of this decreased labor time and increased profit for all farmers.



In order to construct a wind farm many things are taken into consideration such as the location of the farm, the amount and the consistent of the wind and the migration patterns of animals. Many years or research have to be done in order for a wind farm to be constructed. Flight patterns of birds, wind patterns, temperature fluxuation and local interest all have to be taken into consideration. Towers generally vary in height from 30 to 60 meters. The towers primarily are guyed steel-pipe structures which are left to collect data for one to two years and then disassembled. Data is collected by a data logging device which stores and transmits data for analysis. Great attention must be paid to the exact positions of the turbines because a difference of 30 meters can nearly double energy production. Studies also have to be done to look at how many rows and columns of mills can be placed on one farm to still have a sufficient production of power. The "wind park effect" refers to the loss of output due to mutual interference between turbines. As a general rule, wind generators are practical if wind speed is 10 mph or greater. An ideal location would have a near constant flow of non-turbulent wind throughout the year with a minimum likelihood of sudden powerful bursts of wind. An important factor of turbine sitting is also access to local demand or transmission capacity.  Since most wind power can’t be stored the power generated has to be used right away or it is lost. This posts a problem where most power is needed during the day and not at night meaning that most of the power generated at night goes to waste. One major problem is that wind energy from a particular turbine or wind farm does not have as consistent an output as fuel-fired power plants; utilities that use wind power provide power from starting existing generation for times when the wind is weak thus wind power is primarily a fuel saver rather than a capacity saver. The strength of wind varies, and an average value for a given location does not alone indicate the amount of energy a wind turbine could produce there. To assess the frequency of wind speeds at a particular location, a probability distribution function is often fit to the observed data.



When selecting a location for a wind farm the main consideration is the wind. A farm can be placed in land, along a shore or off shore. With the stead wind from the seas an off shore farm is often ideal for energy production. One problem with off shore farms is the integrity of the wind mills. Erosion of the mills is a major problem along with the obstruction of shipping lanes. 





 A wind turbine is a rotating machine which converts the kinetic energy of wind into mechanical energy. If the mechanical energy is used directly by machinery, such as a pump or grinding stones, the machine is usually called a wind mill. If the mechanical energy is instead converted to electricity the machine is called a wind generator, wind turbine , or an aerogenerator. <span style="font-family: 'Cambria','serif'; mso-ascii-theme-font: major-latin; mso-hansi-theme-font: major-latin;">