No comments | Tuesday, March 05, 2013
Energy sources of world:
A century ago, few homes had electricity and cars were a rare sight. Today, much of the world's energy is turned into electricity for homes to power equipment in factories and to fuel our cars, buses, aircrafts and other transport. These are some of the main sources of this energy.


Energy sourceThe first  oil wells were drilled less than 150 years ago but oil, and petroleum which comes from it, has become the most important energy source. Almost 40 percent of the world's energy supply comes from oil. Most oil is found in the Middle East and has to be taken by tankers or pipelines to places where it is used around the world.


Flowing water has been used as a power source since the Middle Ages and water mills were once a common sight. Modern hydropower uses water flowing through turbines in dams to produce electricity.

Solar energy-

The Sun's warmth can be stored to produce energy. In ancient times, glass and mirror were utilized to collect heat, but the first houses to use solar heating didn't construct until 1955. Solar energy is becoming more famous and the technology is improving all the time. The world's largest solar energy generating plants are in the Mohave Desert, California (USA). They are designed to use the Sun's rays to heat oil which drives a generator. It creates enough electricity for a small town.


Coal is the world's second most important source of energy. It makes up about 27 percent of the total. Coal is a fossil fuel and is made from plants that lived and died in swamps 300 million years ago. The world's coal reserves will last about another 192 years. This is nearly three times as long as gas (67 years) and almost five times as long as oil (41 years).

Natural gas-

The third main source of power comes from gas that occurs naturally beneath the Earth's surface. It accounts  for 23 percent of the world total. The gas is mainly methane, with some ethane, propane and other gases. It it collected and taken to where it is needed by pipelines and has replaced the highly polluting coal gas that used to be made by burning coal.

Nuclear power-

The fourth most important power source about 7% of the world total is nuclear power. A nuclear reaction releases huge amounts of heat which in turn heats water or other liquid and drives a turbine to produce electricity. The first nuclear power station to produce electricity for public use was Calder Hall, UK which opened in 1956.

Tidal energy-

Using waves and marine currents to release energy is expensive and as yet small-scale. The first and largest tidal power station on the Rance river, St Malo, France, was completed in 1967. 120,000 households got power every year from this power station which produce enough energy.

Wind energy-

In the 7th century windmills were used in Persia (now Iran) and in Europe since the 12th century, but they first used for making electricity in the late 19th century. Today, world's leading area for wind-generated electricity is California, (USA). Tehachapi Wind Resource (California) creates as much wind energy as the rest of the USA added. 

How much energy?:
All electrical appliances use energy. The amount depends on their size and purpose: an electric heater might use ten times as much energy as a single light bulb. The energy an appliance uses is measured in watts. These are named in honour of Scottish engineer James Watt (1736-1819) who first worked out how to measure energy.

Appliance Watts
Air Conditioner   2500-3000
Central heating pump   800
Computer   400
Deep freeze   1000-2000
Dishwasher   2000-2500
Electric kettle   2200-3000
Electric razor   6
Fan   50-100
Fluorescent light   60
Food mixer   4500
Hair dryer   1000-1500
Iron   1000-1500
Light bulb   100
Microwave oven   1500
Photocopier   1500
Printer   350
Radio, CD player   40-200
Refrigerator   1000
Sewing machine   100
Toaster   750-1500
TV (colour)   250
Vacuum cleaner   800-1400
Washing machine   3000-4000


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