This mechanical energy can then be used to power machinery like pumps and grinding stones – usually called a windmill.
The mechanical energy can also be converted into electrical energy, and this device is called a wind generator. Because wind turbines today are mainly used for electricity generation, speaking of a wind turbine is synonym to a wind generator.
In Nusa Penida Bali Indonesia have 9 units of wind turbine power station with total capacity 735 kW. They made from Dutch, Denmark and China and can lighting 20 county or same as 4,000 families in Nusa Penida.
Wind speed in Bali is very fluctuating so the electric generating can not maximum like in the Europe country, the wind speed can reach 12 until 14 m/sec. In Indonesia only six areas the wind speed can reach above 6 m/s, there are in Timor, Kupang, South-East of Celebes, Selayar and Sidrap island.
History of Wind Turbines
Wind turbines of machines dates back as early as 200 B.C in Persia. The Romans adopted this technology in 250 A.D, but the first practical windmills were built in Iran from the 7th century. These windmills, made up of long vertical drive shafts and rectangular shaped blades were used to grind corn, and pump water. The wind turbine technology was mainly used in the sugarcane industries.
Wind turbine technology gave its real birth in Europe. Dutch windmills were used to drain areas of the Rhine River delta. Denmark had about 2500 windmills at the end of the 19th century. These wind turbines were used as pumps and mills, and the estimated total wind power generation of all these windmills was estimated to be about 30MW.
The first electricity generating wind turbine or windmill was a battery charging machine – installed in 1887 by James Blyth, from Scotland.
United States adopted Europe’s wind turbine technology, and the first electricity generating windmill was built in Cleveland, Ohio by Charles F Brush in 1888. By 1908 there were 72 electricity generating wind turbines. During the period of the First World War, windmill makers were producing about 100 000 farm windmills each year. Most of these wind turbines were used to for water pumping. The 1930’s saw an increase in windmills for electricity generation, and were a common sight all around the world.
Russia built the first100kW generator in 1931, in the district called Yalta. The wind turbine was mounted on a 30m tower, connected to a 6.3kV distribution system.
The first utility gird connected wind turbine operated in the UK. This wind turbine was built by the John Brown Company in 1954, Orkney Islands.
Usually flat objects connected to a center shaft that converts the push of the wind into a circular motion in a wind turbine. Most wind turbines have three blades. Very small turbines may use two blades for ease of construction and installation. Vibration intensity decreases with larger numbers of blades. Noise and wear are generally lower, and efficiency higher, with three instead of two blades.
Turbines with larger numbers of smaller blades operate at a lower Reynolds number and so are less efficient. Small turbines with 4 or more blades suffer further losses as each blade operates partly in the wake of the other blades. Also, the cost of the turbine usually increases with the number of blades.
One of the strongest construction materials available (in 2006) is graphite-fibre in epoxy, but it is very expensive and only used by some manufactures for special load-bearing parts of the rotor blades. Modern rotor blades (up to 126 m diameter) are made of lightweight pultruded glass-reinforced plastic, smaller ones also from aluminium, or sometimes laminated wood.
Where to Build Wind Turbines?
We already know that wind turbines create electricity from wind energy. That means a wind turbine should be built at a location with constant high wind speeds. Scientists and engineers usually estimate the energy potential of a region with a wind resource assessment.
WPF, or wind power density, is a calculation relating to the effective force of the wind at a specific location. It’s expressed in terms of elevation above ground level over a specific interval or period of time. The two variables used are wind velocity and mass.
After the wind resource assessment has been done, colour coded maps are prepared for the specific region. The results are included in the National Renewable Energy Lab’s database, and referred to as “NREL CLASS”.
Related Link
Nuclear in Indonesia
Geothermal in Indonesia
OTEC in Indonesia
No comments:
Post a Comment