Cheap, green hydrogen would be a massive breakthrough in clean energy... Methane (CH4) is the primary fossil fuel used to produce hydrogen now. When it reacts with water (H2O) at a high temperature, both H2 and CO2 are produced. However, through a different heating process that happens in the absence of oxygen, called pyrolysis, it’s possible to separate the hydrogen atoms and leave just solid carbon—think of the lead in a pencil.
