Total hypothetical situtation (so, there's no need to yell at me).
You have a methane digester in your home producing CH4. The CH4 is piped to a kitchen stovetop, oven and then burns in a radiant heat flooring furnace. Excess CH4 from say, ten different homes is then piped to a diesel genset converted to burn methane. Generator can run a
grand total of say, two hours, maybe. Generator recharges deep cycle batteries in the homes for 2 hours.
System has a 12 volt wind turbine on the porch that also charges the batteries.
Let's load the system. Cold weather hits, furnace needs to run more often and CH4 is quickly depleted and takes several hours to fill back up. Not enough CH4 to run the generator, probably not enough to keep the furnace running.
Now, in this case, and this case only, would it be practical to produce
the single most inefficient fuel gas in the world---hydrogen? To have a
hydrogen generator connected to the batteries in order to convert surplus energy from the generator and wind turbine into hydrogen gas? Then, when the CH4 isn't enough, to burn the hydrogen (yes, I know it needs different fittings, it's just hypothetical) at least in the furnace? Or is hydrogen so inefficient to generate and compress it's just not worth the time? Would it just be cheaper to run the stove off electricity----another energy hog?
Just go out and buy a bottle of liquid natural gas?