Source of Electrical Energy full detail.

Source of Electrical Energy

Since electrical energy is produced from energy available in various forms in nature, it is desirable to look into the various sources of energy. These sources of electrical energy are :

(i) The Sun (ii) The Wind (iii) Water (iv) Fuels (v) Nuclear energy.

Out of these sources, the electrical energy due to Sun and wind has not been utilised on large scale due to a number of limitations. At present, the other three sources viz., water, fuels and nuclear energy are primarily used for the generation of electrical energy.

(i) The Sun. 

Sun Energy

The Sun is the primary source of electrical energy. The heat energy radiated by the Sun can be focussed over a small area by means of reflectors. This heat can be used to raise steam and electrical energy can be produced with the help of turbine-alternator combination.
 However, this method has limited application because :

(a) it requires a large area for the generation of even a small amount of electric power.
(b) it cannot be used in cloudy days or at night.
(c) it is an uneconomical method.

Nevertheless, there are some locations in the world where strong solar radiation is received very regularly and the sources of mineral fuel are scanty or lacking. Such locations offer more interest to the solar power plant builders.

(ii) The Wind.

Wind Energy

 This method can be used where wind flows for a considerable length of time. The wind energy is used to run the wind mill which drives a small generator. In order to obtain the electrical energy from a wind mill continuously, the generator is arranged to charge the batteries.
These batteries supply the electrical energy when the wind stops. This method has the advantages that maintenance and generation costs are negligible.
 However, the drawbacks of this method are
(a) variable output,
(b) unreliable because of uncertainty about wind pressure
(c) electrical power generated is quite small.

(iii) Water. 

Water Energy

When water is stored at a suitable place, it possesses potential energy because of the
head created. This water energy can be converted into mechanical energy with the help of water turbines. The water turbine drives the alternator which converts mechanical energy into electrical
energy.
This method of generation of electrical energy has become very popular because it has low production and maintenance costs.

(iv) Fuels. 

The main sources of energy are fuels viz., solid fuel as coal, liquid fuel as oil and gas
fuel as natural gas. The heat energy of these fuels is converted into mechanical energy by suitable prime movers such as steam engines, steam turbines, internal combustion engines etc. The prime mover drives the alternator which converts mechanical energy into electrical energy. 

Although fuels continue to enjoy the place of chief source for the generation of electrical energy, yet their reserves
are diminishing day by day. Therefore, the present trend is to harness water power which is more or less a permanent source of power.

(v) Nuclear energy.

Nuclear Energy

 Towards the end of Second World War, it was discovered that large amount of heat energy is liberated by the fission of uranium and other fissionable materials. It is estimated that heat produced by 1 kg of nuclear fuel is equal to that produced by 4500 tonnes of coal. The heat
produced due to nuclear fission can be utilised to raise steam with suitable arrangements. The stream can run the steam turbine which in turn can drive the alternator to produce electrical energy. 

However, there are some difficulties in the use of nuclear energy. The principal ones are
(a) high cost of nuclear plant
(b) problem of disposal of radioactive waste and dearth of trained personnel to handle the plant.

Compression of electrical energy sources

The chief sources of energy used for the generation of electrical energy are water, fuels and nuclear energy.