Sure, but if you want hydrogen in order to burn it wit oxygen and make heat and water in large scale then getting hydrogen from water is obviously not an option because of thermodynamics 101.
If you need hydrogen for something else, or if you need it to burn it with oxygen in some special application (e.g. rocket propulsion), then it may an option.
is obviously not an option because of thermodynamics 101
It is a perfectly good option if you need hydrogen as energy carrier and not as energy source.
Epic work, it's always fascinates me when author explores the topic so deep, that doesn't know where to begin, so finally starts with the whole history of the universe or the existence of human race.
http://waitbutwhy.com/2015/08/how-and-why-spacex-will-colonize-mars.html