Energy is the building block of all activities in the universe. Anything we do requires energy. As such, it is important to understand what exactly energy conversion means, how it works and what are the consequences of it.

The law of Conversion of Energy

The law of conversion of energy is one of the fundamental laws of Physics. It states that energy can neither be created, nor destroyed. It is merely transferred from one form to another. It implies that in a closed system, the net total energy will always remain constant.

The production of light from a bulb is one of the examples of energy conversions from one form to another. Here, electric energy is transformed into light and heat energies.

Energy transformation or energy conversion is the process of changing one form of energy to another form of energy. In physics, the term energy describes the capacity to produce certain changes within any system, without regard to limitations in transformation imposed. Changes in total energy of systems can only be accomplished by adding or removing energy from them, as energy is a quantity which is conserved (unchanging), as stated by the first law of thermodynamics. Mass-energy equivalence, which rose up from special relativity, states that changes in the energy of systems will also coincide with changes (often small in practice) in the system’s mass, and the mass of a system is a measure of its energy content. The process of something happening (forming).

Types of energy conversions

In theory, any kind of energy can be converted into any other kind. The various types of energies are listed  below:

  • Sound energy ( from sound waves)
  • Mechanical energy (walking, running)
  • Electrical energy (from the movement of electrons in an atom)
  • Light energy
  • Nuclear energy (nuclear fusion and fission)
  • Thermal energy ( from heat)
  • Chemical energy (fuel, gas, battery)


Energy in many of its forms may be used in natural processes, or to provide some service to society such as heating, refrigeration, light, or performing mechanical energy to operate machines. For example, an internal combustion engine converts the potential chemical energy in gasoline and oxygen into thermal energy which, by causing pressure and performing work on the pistons, is transformed into the mechanical energy that accelerates the vehicle (increasing its kinetic energy). A thermal or heat energy converts the chemical energy into mechanical energy that can then be used in a party.

There are many different machines and transducers that convert one energy form into another. A short list of examples follows:

  • Thermoelectric (Heat → Electric energy)
  • Geothermal power (Heat→ Electric energy)
  • Heat engines, such as the internal combustion engine used in cars, or the steam engine (Heat → Mechanical energy)
  • Ocean thermal power (Heat → Electric energy)
  • Hydroelectric dams (Gravitational potential energy → Electric energy)
  • Electric generator (Kinetic energy or Mechanical work → Electric energy)
  • Fuel cells (Chemical energy → Electric energy)
  • Battery (electricity) (Chemical energy → Electric energy)
  • Fire (Chemical energy → Heat and Light)
  • Electric lamp (Electric energy → Heat and Light)
  • Microphone (Sound → Electric energy)
  • Wave power (Mechanical energy → Electric energy)
  • Windmills (Wind energy → Electric energy or Mechanical energy)
  • Piezoelectrics (Strain → Electric energy)
  • Friction (Kinetic energy → Heat)
  • Electric heater (Electric energy → Harsh)