0NobodyInParticular 9 years ago ReplyUpvoteIt requires a very large amount of energy to separate hydrogen from water by electrolysis.After doing that, you have to contain the hydrogen in such a way that the container doesn't run out quickly but also can't explode during an accident.When you burn it in an engine, the hydrogen doesn't give back much of the energy you put into the electrolysis. (Fuel cells are a better way to use it anyway.)So what you're proposing is currently rather wasteful of energy. (If you live in the US, that energy is probably coal.) But it certainly is possible.