Difference Between Electrical Energy and Electrical Power

Electrical Energy vs Electrical Power
 

Electric energy and electric power are two very important quantities in electricity and electronics. This article will compare the two concepts and present the similarities and differences between these two quantities.

What is Electrical Energy?

Electrical energy is the name given to the work done by the electrical potential energy. Understanding in electrical potential is required to understand the concept of electrical energy. An electric field is said to be produced by all electric charges whether they are moving or stationary. An electric field can also be produced using any time varying magnetic fields. There are several salient factors of electric fields. These are electric field intensity, electric field potential and electric flux density. The electric field intensity is defined as the force on a unit point charge from the electric field. This is given by the formula E = Q/4πεr², where Q is the charge, ε is the electric permittivity of the medium, and r is the distance of the point from the point charge Q. The force on a point charge q placed on that point is equal to F=Qq/4πεr². If q is 1 coulomb, F is equal to the electric field intensity. The electric potential of a point is defined as the energy required to bring a point charge of 1 coulomb from infinity to the point the potential is measured. This energy is equal to the work done on the charge when bringing the charge from infinity to the point. If both the charges are positive, the force that has to be applied to take the test charge from infinity to the point is always equal and antiparallel to the repulsion force between the two charges. Integrating F from infinity to r, with respect to dr, we get the electric potential (V) of the point as Q/4πεr. Since r is always positive, if the charge is negative, the electric potential also is negative. The units of electric potential are joule per coulomb. A static electric field is a conservative field. Therefore, the electric potential of a static electric field is path independent. The electric potential of such field depends only on the position. A free charge placed in an electric field tends to move towards the lowest potential energy possible. This flow of charges would cause the potential of the low potential end to be heightened, thus reducing the potential difference. This reduced potential energy will eventually stop the flow of charges. Electric energy is the energy that is required to keep the potential difference at two points. Electric energy is measured in joules. Electric energy can also be interpreted as the amount of work required to move the charge in the electric field.

What is Electric Power?

Electric power is the rate of generation of electric energy. This is measured in watt or joules per second. Even though electric energy is the more fundamental quantity electric power is the useful quantity in the power system management. Since electric power is the rate of electric energy transmission, this quantity is vital in designing withstanding systems.