Yeah, imagine you have whole lot of hydrogen and no oxygen to get it to burn. You are going to freeze to death while moving nowhere. About the only good thing

Yeah, imagine you have whole lot of hydrogen and no oxygen to get it to burn. You are going to freeze to death while moving nowhere. About the only good thing it could be used for is reaction mass. But you can use almost anything as reaction mass as long as you have a source of energy, you can exhaust any particles to propel yourself forward, doesn't have to be hydrogen.