Electricity and its Sources: Electric Charge, Current, Different Sources

Electricity and its Sources: Electricity has become one of the most useful resources for our daily lives. Due to advancements in technology, we can hardly think of any place where electricity is utilized. We convert electrical energy to many other different forms of energy according to our use. For example, in a tube light or a bulb, we convert electrical energy into light energy. In a fan, we convert electrical energy into wind energy. For a heater, we convert electrical energy to energy, etc., and there are many more such examples where we use electricity regularly. Nowadays, electricity is also useful for household work like cooking, washing and even for leisure. This may rightly conclude that electricity has a big impact on our day-to-day lives.

Electric Charge and Electric Current

Electric charge is an intrinsic property of any substance. We cannot create it, nor we can destroy it; we can just transfer it from one object to another object. Due to the presence of an electric charge, the substance or the particle may experience an electric force in the presence of an electromagnetic field. Electric charge is of two types – (1) positive charge and (2) negative charge. A positive charge on any substance is due to a deficiency of electrons which means electrons are removed from the substance in order to generate a positive charge on it. Whereas negative charge on any substance is due to excess of electrons, which means, electrons are added to the substance in order to generate negative charge in it. This means the charge in a substance is all due to electrons only. Hence, the charge is given by the equation:

q=Ne

Here,
N is the number of electrons added or removed,
e is the charge of an electron e=1.6×10-19 C

Electric current is the flow of electric charge with respect to time. It flows through conductors like copper wires and helps in the transmission of electricity. At our home, electric current flows through the wires, which is then transmitted to our devices. Thus, electric current through a conductor is given by:

i=qt

Electricity

Electricity and electric current are not the same quantities. Electric current is a part of electricity. Electricity is, in turn, a broader concept. Let us first look at electrical energy. It is an energy associated with the flow of electric charge. Let us understand this by looking at a conductor.

Since a conductor is made of metal, there are many electrons present in it. 

These electrons perform random motion inside the conductor and lose energy while reaching its end. When the battery is connected to the conductor, as shown in the diagram, the de-energized electrons get attracted to the positive terminal of the battery. The battery provides energy to these electrons, which is known as electrical energy, and along with that energy, they enter back into the conductor, again start performing the random motion, collide with other electrons and finally lose their energy again and continue the cycle. Thus, energized electrons flow through a conductor generating electricity inside the conductor with the help of a battery.

So, electricity is basically the flow of electrical energy which the electrons carry throughout the conductor. Or else, we can also call electricity electrical power. So basically, whenever we talk about the generation or transmission of electricity, we actually talk about the generation or transmission of electrical power.

Sources of Electricity

Here, we are going to discuss about the seven basic sources of electricity and how exactly is electricity is generated using them.

1. Rubbing

This was actually the very first attempt to generate electricity which dated back during BCE. When we rub a glass rod on a silk cloth or an amber bar on tanned skin, they produce a small attractive force towards each other which wasn’t present earlier. This gave rise to static electricity, and the whole concept was to be known as electrostatics, where the study of charges began. What exactly happened in the process is that when the silk cloth is rubbed against the glass rod, electrons from the glass rod gets transferred to the cloth. Due to this, a negative charge is generated on the glass rod, and a positive charge is generated on cloth, and hence an attractive force between negative and positive charges occurs. This phenomenon can even be observed when you rub your bare feet against the carpet multiple times, and someone unknowingly touches your skin. They might feel a slight shock from your body.

2. Chemical Reaction

Chemical reactions are the source of electricity in batteries. A battery contains electrodes and electrolytes, as shown in the diagram.  Here, as you can see that one of the electrodes (Cu electrode) acts as an anode and the other electrode (Zn electrode) acts as a cathode. Positive and negative charges get accumulated from the electrolyte (sulphuric acid) on anode and cathode, respectively, and a potential difference is built up between them. Due to this potential difference, when we connected a load across the electrodes, a current flowed between them. This complete structure forms a battery, and such batteries are used to avail direct current in smaller circuits.

3. Solar Energy

Technology to use solar energy to generate electricity is increasing rapidly. Huge investments are made on this technology because it uses a renewable source of energy. It basically uses a solar cell to generate electricity, as shown in the diagram. The solar cell is made up of semiconductor material which is doped silicon. Sunlight is absorbed by the semiconductor material of the cell. The energy of electrons in the semiconductor increases, and they are excited to conducting state. Due to this, the solar cell gets forward biased, and a potential difference is induced across the external load which is shown in the diagram, due to this potential difference, a current flow through it. This technology is an emerging technology, and huge investments are being made after it.

4. Thermal Energy

Sources like coal, oil, natural gas, etc., which are used to generate heat, can also be used to generate electricity through heat. The steam after burning coal is pressurized and passed on to a turbine. This turbine is rotated, which is connected to an electrical generator. As the generator rotates, it generates its own electricity. This method is to convert thermal energy to electrical energy, and this method is the most commonly used method to generate electricity because the initial cost to set up a power plant is low, and coal is also available easily at not so higher rate. Its storage and transportation are also easier comparatively. But its main drawback is that it is a non-renewable source which means coal once used cannot be used back, and it is decreasing at a higher rate. Apart from this, it also emits smoke which makes it not suitable to place it near a habituated area.

5. Magnetism

This is one of the most important parts of any power plant. Whenever there is a disturbance in a magnetic field, electricity is generated. This process is known as electromagnetic induction, which means inducing electricity by using magnetism. This was first discovered by Michael Faraday, where he noticed that when a magnet is moved in the vicinity of a coil, electric current is induced in it, and hence he demonstrated that electric current could be produced using a magnetic field. Finally, the concept of electromagnetism arose, and now every power plant uses it. The generator, which is rotated through a turbine, has a shaft inside it covered with a coil which is rotated inside a strong magnetic field, generating a high amount of electric current.

6. Piezo-electricity

It is the method to accumulate electric charge in a certain solid material like crystals, certain ceramics, DNA, etc. Certain material is known as a piezoelectric material generally made up of quartz, is used, which is shown in the diagram. When the material as shown is mechanically deformed or compressed continuously, a small amount of charge gets accumulated on the metal plates connected to the material. These metal plates are connected to an external circuit or a measuring device which is the case shown in the diagram.

The more continuous compression and expansion more is the more electricity generated. In some places, this method is used to generate electricity in small amount and store it. Piezoelectric material is placed under a speed breaker on the road. Whenever a vehicle passes through it, it gets compressed and then expanded, which in turn generates electricity. In such a way, when a huge amount of vehicles passes from the speed breaker, it generates a continuous high amount of electricity. 

7. Hydroelectricity

Electricity generated due to a continuous flow of water is considered to be hydroelectricity. The power plants which are used for such purposes are known as hydroelectric power plants. The diagram here shows the basic portion of a hydroelectric power plant. This plant can be installed wherever there is a huge reservoir of water, for example, a dam.

So, water from a height comes down a penstock, as shown in the diagram towards the power station. Penstock is like a huge pipe that controls the opening and flow of water inside it. When the water reaches the power station, it directly falls on a huge turbine with high pressure. The valve house and surge tank control the intake of water from the dam, and the pressure tunnel gives a direction to the flow of water. This type of plant has many advantages that its maintenance is very less, and it uses renewable sources of energy, and it also has no pollution. But the only disadvantage is that it can be only installed at places where there is an ample amount of water available, and its one-time installation cost is also very high.

Summary

Reading this article, we came to know about the electric charge, which is an intrinsic property of a matter due to which it experiences a force when placed in an electromagnetic field. We studied about the positive charge and negative charge. Then we looked into electric current, which is the flow of electric charge. Further, we studied electrical energy and electricity. Electricity is nothing but simply the flow of electrical energy which is carried by electrons inside a conductor.

After these basics, we went through different sources of electricity, discussed about their working, advantages as well as disadvantages. The seven different sources of electricity are – (1) rubbing, (2) chemical reaction, (3) solar energy, (4) thermal energy, (5) magnetism, (6) piezoelectricity and (7) hydroelectricity. Every source has its own importance, advantages and disadvantages and generates electricity by different methods.

Frequently Asked Questions

Q.1. What is the largest source of electricity?
Ans: Currently, the largest source of electricity is a thermal power plant, a type of non-renewable source.

Q.2. What are the seven sources of electricity?
Ans: The seven sources of electricity are (1) rubbing, (2) chemical reaction, (3) solar energy, (4) thermal energy, (5) magnetism, (6) piezoelectricity and (7) hydroelectricity.

Q.3. What is a good source of electricity?
Ans: A good source of electricity must be cost-efficient, convenient, pollution-free, easily accessible and cheap.

Q.4. What are the three types of fuels?
Ans: The three types of fuels are coal, natural gas and oil.

Q.5. What is hydroelectricity?
Ans: Hydroelectricity is the electricity generated due to the pressure of the water falling on the turbine. It is a clean source of electricity as compared to the thermal power plant.

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