The Peak Oil discussion indicates that a change of worlds energy supply will occure.
Most important renewables are solar and wind power based options, currently available mainly as electricity. Looking at the very limited battery or hydro storage capacities, sector coupling and Power-to-Gas are very likely to become an important part of the energy chain, therewith our pipeline systems are becoming a new role as chemical batteries.
First and most basic step to this new pipeline characteristic is the electrolytic production of hydrogen and infeed into the existing natural gas pipeline grid.
As the existing grid is designed and optimized for natural gas - mainly methan - transport, the specific properties of hydrogen require some adaptions from both gas grid and hydrogen infeed. Methanation may be a perfect adaption by the producer side, but cause extra effort compared to the infeed of pure hydrogen.
It is given an overview of motivation, current state of electrolyser revival (PEM and alkaline) and hydrogen properties which may interfere with the natural gas supply system, technically and by regulation. Coming down to examples of recently realised implementations of hydrogen infeed projects, some solutions are presented.