Fuel is any material that's burned or altered to obtain energy and to heat or to move objects. Fuel releases its energy either through a chemical reaction means, such as combustion, or nuclear means, such as nuclear fission or nuclear fusion. An important property of a useful fuel is that its energy can be stored to be released only when needed, and that the release is controlled in such a way that the energy can be harnessed to produce work. Examples: Methane, Petrol and Oil. All carbon-based… (More on Fuel)