A problem with making methane is some will leak, and in the short to medium term methane is a very powerful greenhouse gas.
A step before making methane is making hydrogen. If you can get away with just using hydrogen, it will be more efficient than going through the extra steps to make methane.
A step before making methane is making hydrogen. If you can get away with just using hydrogen, it will be more efficient than going through the extra steps to make methane.