A fuel is a substance that provides a form of energy—such as heat, light, electricity, or motion—as the result of a chemical change. This change from one form of energy to another is called energy transformation. used to generate other forms of energy, such as motion or electricity.Energy forms are either potential or kinetic. Potential energy comes in forms that are stored including — chemical, gravitational, mechanical, and nuclear. Kinetic energy forms are doing work — like electrical, heat, light, motion, and sound.