Electrical Energy- Definition, Examples, Formula and Units

Well, what is Electrical Energy.? How does it work? To better understand all these concepts of Electrical energy, let us discuss some basics about Energy.
Energy is nothing but the ability to do any work. Where work is done when a force moves an object from one position to another. We use energy every day, which is available in all different forms. Electrical energy is also one of the forms of energy that's stored in the electric field by a charged particle.
Electric fields are simply area surrounding a charged particle. In other words, charged particles create electric fields that exert force on other charged particles within the field.

Electrical Energy Definition

Electrical Energy is defined as the form of energy which is caused by the movement of the electrons from one point to another, then such type of energy is called electrical energy.

In other words, electrical energy is nothing but the work done by the moving electrons or charges in the electric field.

As we explained above Energy is the ability to do work or apply a force to move an object from one position to another. So in the case of electrical energy, that force is electrical attraction or repulsion force between the charged particles.

Electrical energy can be either potential energy or kinetic energy. But it's usually encountered as potential energy, which is energy stored due to the relative positions of charged particles in the electric fields. The movement of charged particles through a conducting medium (conductors or wires) is called Current Electricity.

There is also a concept of Static electricity, which results from the separation of positive and negative charges. Static electricity is a form of electrical potential energy, whereas Current electricity is a form of Kinetic Energy. If sufficient charge builds up, then the electrical energy may be discharged as a spark (or even lightning), which has electrical kinetic energy.

How does Electrical Energy work?

To better understand the concepts of Electrical Energy, it is essential to know How does Electrical Energy work? Basically, electrons and protons are very crucial to make the electricity to work.

So the basic working principle is that electrons in copper wire are free to move. Each electron carries a negative charge. So It’s movement is due to attractive forces between the electron and positive electrical charges (such as protons and positively-charged ions) and repulsive forces between the electron and negative charges (such as other electrons and negatively-charged ions).

In other words, the electric field surrounding a charged particle (an electron, in this case) exerts an attractive or repulsive force on other charged particles, which causes it to move and thus do work. Any charged particles may produce electrical energy, including electrons, protons, atomic nuclei, positively-charged ions, and anions (negatively-charged ions), and so on.

Electrical Energy Formula

To develop Electrical Energy formula, let us consider a simple circuit which contains an energy source (battery), a Resistance and a conducting wire to complete the path for current. 

Let us assume the potential difference between point A  and Point B is V volts. If a charge Q coulomb travels from point A to B in time t sec. then, Current I amp is flowing through resistance R in the circuit.

Then work done by the charge will be V*Q joules.                  

Since Electrical Power is defined as electrical work done per unit time. So in the differential form, we can write as 

Since current (I) = dQ/dt

So we can write Power (P) = V*I  watts

If current I flows through conductor for a time t sec then total work done by the charge Q will be 

E = V*I*t  joules

Hence the formula for Electrical Energy will be 

E = V*I*t  joules

Electrical Energy Units

Basically, the SI unit of the electrical energy is the joule (or watt-second).

If the current of 1 amp flows through the circuit across 1-volt potential difference up to 1 sec time then the electrical energy consumed by the circuit elements will be equal to the one joule (or 1 watt-sec).

But the commercial or practical unit of energy is Watt-hour, kilowatt-hour (kWh), Megawatt-hour (MWh), etc.

Usually, 1 kWh is known as 1 Unit of Electrical Energy.
kWh is also known as the Board of Trade (B.O.T) unit.

1 kWh = 1000*60*60 watt-sec. 

1 kWh = 3600000  joules

Electrical Energy Example

Electrical energy used for working of electrical appliances such as to light a bulb or power a computer is an energy that is converted from electric potential energy. This potential energy is converted into any type of energy (such as heat, light, mechanical energy, etc.). A battery is another source of electrical energy, except the electrical charges may be ions in a chemical solution rather than electrons in a metal.

Biological systems are also using electrical energy. For example, hydrogen ions, electrons or metal ions may be more concentrated on the side of a membrane, setting up an electrical potential that can be used to transmit nerve impulses, move muscles.
Also Read: Concepts of Electrical Power

Here are some specific examples of electrical energy.

Electrical energy is used to power up a light bulb. When a lamp is plugged into a wall outlet. Then current moves from the wall outlet (source) to the light bulb through the conducting wire. Light energy is then created when the electric charges slow down in the filament so it could light the bulb.

Lightning is another example of electrical energy. When the negatively charged particles are separated from the positively charged particles. A charge potential develops from this separation. When the separation is fairly high, then discharge takes place. This leads to the flow of current in the atmosphere. It is the form of lightning also another example of Electrical Energy.

Batteries are also sources of electrical energy. In car batteries, the chemical reaction creates an electron which provides electrical energy to the circuits of the car. Also in phone batteries, the stored chemical energy supplies the power to phone circuit in the form of electrical energy so that the phone operates.

When our bodies break down food to produce ATP energy. Our bodies convert ATP energy into electrical energy. Then the electric charges move through our special nervous system cells to make our heartbeat.

Some other specific examples of electrical energy include alternating current (AC) and direct current (DC), capacitors, and the energy produced by electric eels.