Next time you visit university do ask professors what happens when you burn hydrogen. HINT: It's water. 'cause burning is usually when something reacts with oxygen. Hence: 2x H2O + energy (electrical) -> 2x H2 + O2 2x H2 + O2 -> 2x H2O + energy (thermal) if energy in 1st and 2nd equation are not equal - you've just broken US dependency on foreign oil (figures out the way for humanity to survive after the sun burns out, etc) 'cause you can run these two reactions in infinite loop and pocket the difference in energy. sorry for the off-topic.
You actually require as much energy to break H and O than you receive from fusionning them via combustion.... However, there is always energy losses, in both the regular equation and its inverse. Water4gas technology => Hoax Until we find a easier way to get hydrogen than breaking water. A good solution would be to break fuel. Theres alot of H in fuel.