Hydrogen is bound in both compounds - you need to expand energy to extract it. As in our oxidizing atmosphere natural gas is a source of (chemical) energy, you

Hydrogen is bound in both compounds - you need to expand energy to extract it. As in our oxidizing atmosphere natural gas is a source of (chemical) energy, you can burn it to provide the energy needed to extract the hydrogen. This is the steam reforming reaction. Since water is not a source of energy, you need to add (expensive) electrical energy in order to extract the hydrogen. This is the electrolysis reaction.