Hydrogen combines with oxygen when it is burned and produces water as a by-product. Insignificant amounts of nitric oxides are also formed in areas around the combustion zone.
Water can be readily split into hydrogen and oxygen using electricity. This process is known as electrolysis. The hydrogen captured in this process can be burned, where it combines with oxygen from the air and becomes transformed into water once again. This process can be repeated in an ongoing cycle, as long as there is a constant input of electricity into the system. However, it takes more electricity to split the water into its component parts than could be produced by burning the hydrogen.