Hydrogen

• Hydrogen gas can be produced from water, by running an electrical charge through the water to separate the hydrogen and oxygen molecules. Hydrogen burns cleanly, producing only water as a byproduct.
  
  

Fuel Cells

• Hydrogen fuel cells certainly exist; they are used in high-technology settings, like aerospace. You can build a fuel cell at home to demonstrate this principle. Hydrogen fuel conversion kits and plans allow you to convert your car to run on hydrogen gas instead of gasoline.
  
  

Warning

• Though you can theoretically construct a hydrogen fuel cell and convert your car to run on hydrogen, actually running your auto on hydrogen is not feasible at this time due to a lack of infrastructure to supply hydrogen for auto fuel. Hydrogen requires more energy to produce from water than it can provide, creating further obstacles.