# WIND POWER What is it How does it work Efficiency U.S. Stats in addition to Examples By:

## WIND POWER What is it How does it work Efficiency U.S. Stats in addition to Examples By:

This Particular University is Related to this Particular Journal

A typical 600 kW wind turbine has a rotor diameter of 43-44 meters, i.e. a rotor area of some 1,500 square meters. The rotor area determines how much energy a wind turbine is able to harvest from the wind. Since the rotor area increases with the square of the rotor diameter, a turbine which is twice as large will receive 22 = 2 x 2 = four times as much energy. To be considered a good location as long as wind energy, an area needs to have average annual wind speeds of at least 12 miles per hour. WINDMILL DESIGN A Windmill captures wind energy in addition to then uses a generator to convert it to electrical energy. The design of a windmill is an integral part of how efficient it will be. When designing a windmill, one must decide on the size of the turbine, in addition to the size of the generator. LARGE TURBINES: Able to deliver electricity at lower cost than smaller turbines, because foundation costs, planning costs, etc. are independent of size. Well-suited as long as offshore wind plants. In areas where it is difficult to find sites, one large turbine on a tall tower uses the wind extremely efficiently.

SMALL GENERATORS: Require less as long as ce to turn than a larger ones, but give much lower power output. Less efficient i.e If you fit a large wind turbine rotor with a small generator it will be producing electricity during many hours of the year, but it will capture only a small part of the energy content of the wind at high wind speeds. LARGE GENERATORS: Very efficient at high wind speeds, but unable to turn at low wind speeds. i.e If the generator has larger coils, in addition to /or a stronger internal magnet, it will require more as long as ce (mechanical) to start in motion. A windmill built so that it too severely interrupts the airflow through its cross section will reduce the effective wind velocity at its location in addition to divert much of the airflow around itself, thus not extracting the maximum power from the wind. At the other extreme, a windmill that intercepts a small fraction of the wind passing through its cross section will reduce the winds velocity by only a small amount, thus extracting only a small fraction of the power from the wind traversing the windmill disk. Modern Windmills can attain an efficiency of about 60 % of the theoretical maximum. P/m^2 = 6.1 x 10^-4 v^3 The power in wind is proportional to the cubic wind speed ( v^3 ). WHY ~ Kinetic energy of an air mass is proportional to v^2 ~ Amount of air mass moving past a given point is proportional to wind velocity (v)

An extra meter of tower will cost roughly 1,500 USD. A typical 600 kW turbine costs about \$450,000. Installation costs are typically \$125,000. There as long as e, the total costs will be about \$575,000. The average price as long as large, modern wind farms is around \$1,000 per kilowatt electrical power installed. Modern wind turbines are designed to work as long as some 120,000 hours of operation throughout their design lifetime of 20 years. ( 13.7 years non-stop) Maintenance costs are about 1.5-2.0 percent of the original cost, per year. The U.S. currently has more than 1,600 MW of installed capacity in addition to produces about 3 billion KWh of electricity each year. This is enough to meet the annual residential needs of 1 million people. More than 90 percent of this power is produced by three wind farms in Cali as long as nia (Altamont Pass, Tehachapi in addition to Palm Springs).