STORAGE OF ENERGY

Energy can be stored in many forms. Chemical potential energy is stored in fuels such as coal, wood, and food, or in the chemicals in batteries and fuel cells. Phosphorescent materials store some of the energy they absorb from visible light. After a time delay, they convert this energy back into visible light. Often energy storage involves energy conversions. Winding a music box stores the mechanical energy of motion of our arm’s motion as strain potential energy in the music box spring. Gravitational potential energy is stored by raising an object to a higher level.

Unfortunately, electrical energy cannot easily be stored in large amounts. For this reason, generating plants must produce and transmit electrical energy as consumers require it. It is possible to store electrical potential energy in devices called capacitors. For example, cameras use capacitors to store electrical potential energy and then release the energy quickly to produce a flash. But capacitors are not practical for storing large amounts of electrical energy.