This article attempts to list pseudoscientific inventions wherein common water is used to either augment or generate a fuel to power an engine, boiler or other source of power. This is not to be confused with legitimate inventions (such as hydroelectricity) in which the kinetic energy of flowing water is used for power.
The electrolysis of water splits water into hydrogen and oxygen, producing a usable fuel, which, when burned, turns back into water. However, the energy required for electrolysis is greater than the energy released by burning this fuel, so this is not a viable way to manufacture energy. Nonetheless, several people have claimed to create devices that do exactly this.
Ruggero Maria Santilli's "Magnegas" recyclers, which use an underwater carbon arc to gasify bio-contaminated liquid into a clean-burning gas. [7]
Water is claimed to be transformed into a fuel itself, by the addition of some ingredient. This may be either a highly concentrated addition, or a catalyst (i.e. not consumed in use).