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(i) Wind
Wind energy used in wind mills to pump water from wells and low level to high level.
Windmills do not generate electricity but are used to grind grains with large grinding
stones. Today wind is used to make electricity, blowing wind spins the blades on a
wind turbine, which is called wind turbine. The blade of turbine is attached to a hub
i.e. mounted on a turning shaft. The shaft goes through a gear transmission box where
the turning speed is increased. The transmission is attached to a high-speed shaft,
which turn generator that makes electricity. If wind gets too high, turbine has a brake
that will keep blades from turning to fast and being damaged. For efficient working,
wind speeds must be above 12 to 14 miles/hr., to turn the turbines fast enough to
generate electricity. Turbines usually produce 50 to 500 kW of electricity each.
(ii) Wave
Waves are caused by action of winds on sea. Waves can be many meters high and
contain a great deal of energy, which can be harnessed to drive turbines that generate
electricity.
Wave energy can be harnessed in coastal areas, close to shore. There has been one
such device working on the island of Islay in Scotland since early 1990s producing
75 kW of electricity. Wave energy collectors are of 2 main types :
(a) First type directs waves into man-made channels, where the water passes
through a turbine that generates electricity.
(b) Second type uses up and down movement of wave to push air.
Advantages : Non-polluting and don’t affect wild life.
Disadvantages : Turbines can be unsightly and no constant supply of energy. Wave
heights vary.
(iii) Bio fuel:
Bio fuel are transportation fuel like ethanol and bio-diesel that are made from biomass
materials. These are usually blended with petroleum fuels-gasoline and diesel fuel,
but they can also be used on their own. Ethanol and bio-diesel are expensive than
fossil fuels that they replace but are cleaner fuels, producing fewer air pollutants.
Ethanol is an alcohol fuel made from sugars found in grains, such as corn, sorghum
and wheat as well as potato skins, rice etc. Most of ethanol in US is distilled from
corn.
Bio-diesel is a fuel made with vegetable oils, fats or greases such as recycled
restaurant grease. Bio-diesel fuels can be used in diesel engine without changing them. It is fastest growing alternative fuel in US. A safe, renewable, fewer
pollutants,degradable
gregorymasila answered the question on February 22, 2018 at 17:05
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