Sabatier uses hydrogen. As an intermediate, it might be less efficient (and dangerous?) H2O -> H2 + O2| H2 + CO2 -> CH4 +O2 The idea is not new, but it is not

Sabatier uses hydrogen. As an intermediate, it might be less efficient (and dangerous?) H2O -> H2 + O2| H2 + CO2 -> CH4 +O2 The idea is not new, but it is not bad https://en.m.wikipedia.org/wiki/Power-to-gas https://en.m.wikipedia.org/wiki/Power-to-gas