If this is HHO gas, it's quite real with respect to welding and replacing oxy acetylene. And it will enhance the combustion of gasoline. Now, weather or not the energy used to create the gas is less than the energy gained in your engine is the real question. I would think if someone actually designed an ICE to take advantage of HHO injection, and optimized the on board manufacturing of the gas, you may see overall gains. Or perhaps manufacturer it at home (with cheaper electricity) and store it in a vehicle? Kind of like a bottle of nitrous oxide.

It gets late early out there. - Yogi