Noone here is planning to inject hydrogen into existing pipelines. If anything, synthesising methane during the transition so that consumers only have to switch their burners once, from nat gas to hydrogen, and not first to nat gas + more hydrogen and then to pure hydrogen. Gotta switch whole municipalities at once doesn’t make sense to duplicate the last-mile gas pipes. If, and that’s not even clear yet, hydrogen pipes will even be a thing for private consumers.