Energy vs. Power

Difference Between Energy and Power

The power and energy are two terms often used interchangeably. It is very common to see engineers making the mistake of using the power of words and energy interchangeably. The plight of common people and can be easily understood. Although the two terms are very closely related, but are not the same and there are differences between the two. These two terms are easily understood by using a third term called work. Let us see the relationship between the two.


Energy is the ability to do the job. It is a very common word in daily life. It takes energy to do any work. You need energy to move your car. You require energy to heat your home in winter. It is necessary to illuminate the house at night. We use the energy of sunlight to make solar committees. The plants use the suns energy to make food. The energy is present in many forms such as mechanical, thermal, electrical and chemical. Obviously there are nuclear power and nuclear are also used to provide electricity to homes. You can enter any energy source to perform the work. We tap the potential and kinetic energy of water falling from a height to make electricity. In Power plants, coal is burned and chemical energy is converted into electrical energy.

Energy is indestructible and can only change its form. We use the chemical energy of a battery to provide power. To produce the steam we burn coal and other fossil fuels, thereby converting the stored chemical energy into thermal energy. To heat our homes or keep interiors cool, we need to convert electrical energy into thermal energy. The smallest unit of energy is the Joule but insignificant in everyday use which is why we use terms such as watt hour or kilowatt hours.


It is a concept that measures how fast energy is used. So energy is that you deliver and power is the rate at which you deliver. Let us understand this with an example. You are the energy supplied in the form of electricity. The estimated power to different devices tells you how quickly they consume energy. A 100-watt bulb uses energy course at a rate faster than a fluorescent bulb which has an estimated power of 10 watts. So power is the rate at which energy is used. So the unit of power is joules per second.

Speaking of differences, the energy is present in many forms and can be stored while the power cannot be retained. Power only tells how fast energy is consumed rapidly. In different cars, the energy being used is the same but their magnitudes locomotive determines the rate at which energy is used. This is why more small cars have the best fuel efficiency than larger cars.


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