In countries where there is a natural gas network, <i>in theory</i> you could co-transport hydrogen with mixed the methane, and pay around 1% energy cost to extract pure hydrogen (assuming a 20% hyrogen mix). That seems to me to be the simplest way to deploy hydrogen infrastructure - you don't need to build much, and people are already looking at mixing the hydrogen into the natural gas anyway to reduce CO2 output. Eventually you switch over to pure hydrogen and drop the natural gas, saving the extraction cost.<p>But that 1% energy cost is assuming thermodynamically optimal extraction. I don't know how close we get in practice.<p>(I doubt it would be safe to actually have a hydrogen gas pump at everyone's house, either, even if there is a gas line going there, although it would be kind of cool)