That precludes reusing existing infrastructure at the same pressures as today, though. For the same pressure, H2 will leak worse than natural gas.

And it's not just a pressure problem, either: embrittlement will happen at room temperature and pressure, just through diffusion.

Embrittlement is a problem at high pressure because the stuff being embrittled has to be strong to contain pressure. Take away the pressure, and it only needs to not have holes in it.

For decades, lamp gas -- carbon monoxide and hydrogen - was piped to homes, factories, offices, and ... street lamps, in cast -iron pipes. Then they switched to methane, same cast-iron pipes. They started out pretty brittle, really. Still in use, though.

Higher pressure is necessary to keep costs down, smaller pipes and higher pressure is what makes sense for vast majority of liquids and gases.

There will be no need to pipe H2 long distances. It can be made locally from wired in power.

Where a large amount must be handled, underground caverns at low pressure and LH2 tanks at ambient pressure will be favored.