Of course it's possible.
"To understand how these water-fuel systems work, it helps to begin by realizing that ordinary water is actually a "battery" containing vast amounts of energy. Water is H2O — two parts hydrogen combined with one part oxygen. And, as President Bush says, hydrogen is an excellent fuel.
The amount of energy in the water molecule is thus vast, and has absolutely nothing to do with the amount of energy it takes to break down that molecule. This is an extremely important point, as so many people — even scientists — are unclear on this concept. And yet if we can find an economical means to break down the water molecule, our energy problems are over."
